Merge pull request 'push-xvuyuzpqnxzs' (#91) from push-xvuyuzpqnxzs into main

Reviewed-on: #91
2026-04-09 11:21:59 +02:00
parent 4c70a939cd 9dee193947
commit 35e2e037f0
27 changed files with 2146 additions and 260 deletions
--- a/.kilo/plans/1775631632458-happy-cactus.md
+++ b/.kilo/plans/1775631632458-happy-cactus.md
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+# Audit PMO Control - Optimisation Playlist OpenHome
+
+## Résumé Exécutif
+
+L'utilisateur rapporte des lenteurs significatives lors de la manipulation de playlists de ~1000 titres avec les renderers OpenHome. Les renderers Chromecast et UPnP (avec queue interne) ne sont pas affectés.
+
+## État des Optimisations Deja Implémentées
+
+Le precedent plan dans `Blackboard/Todo/enorme_playlist.md` a deja été partiellement implémenté:
+
+| optimisation | Statut | Emplacement |
+|-------------|-------|------------|
+| MAX_BATCH = 256 pour ReadList | ✅ FAIT | `openhome.rs:1015` |
+| Élimination double queue_snapshot() | ✅ FAIT | `replace_queue_with_pivot()` et `replace_queue_standard_lcs()` |
+| LCS préfixe/suffixe (lcs_flags_optimized) | ✅ FAIT | `openhome.rs:869` |
+| Polling adaptatif (is_active) | ✅ FAIT | `musicrenderer.rs:325-374` |
+| Consolidation invalidation caches | ✅ FAIT | `openhome.rs:222-235` |
+
+## Contraintes Protocolaires Découvertes
+
+L'action `Insert` **ne supporte PAS l'insertion par lot** - chaque appel prend un seul Uri/Metadata.
+
+## Nouvelles Optimisations (Contre-propositions Utilisateur)
+
+### OPT-1: Fast Path pour 99% des cas de sync_queue
+
+**Observation**: 99% des changements de playlist sont:
+- Insertion de nouvelles tracks en **fin de queue**
+- Délétion de tracks en **début de queue**
+- Rarement des changements nécessitant un vrai alignement LCS
+
+**Solution**: Ajouter une détection de pattern avant d'appeler LCS:
+
+```rust
+fn smart_sync(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
+    let current_ids = self.track_ids()?;
+    
+    // Cas 1: Append only (insertion en fin)
+    if items.starts_with(&current_ids) {
+        // Fast path: juste ajouter les nouveaux items
+        return self.append_only(items.skip(current_ids.len()));
+    }
+    
+    // Cas 2: Delete from beginning
+    if current_ids.starts_with(&items) {
+        // Fast path: supprimer de la fin
+        return self.delete_from_beginning(current_ids.len() - items.len());
+    }
+    
+    // Cas 3: Full LCS only for complex reorderings
+    return self.replace_queue_standard_lcs(items);
+}
+```
+
+**Impact**: 99% des sync_queue passent de O(N²) à O(N)
+
+---
+
+### OPT-2: Queue FIFO pour Opérations OpenHome (Thread Background)
+
+**Concept**: Une file d'attente FIFO des opérations SOAP exécutée dans un thread dédié.
+
+```rust
+pub struct OpenHomeOpQueue {
+    queue: Arc<Mutex<Vec<OpenHomeOp>>>,
+    worker_handle: Option<JoinHandle<()>>,
+}
+
+pub enum OpenHomeOp {
+    Insert { uri: String, metadata: String, after_id: u32 },
+    Delete { track_id: u32 },
+    DeleteAll,
+    SeekId { id: u32 },
+    Play,
+    Pause,
+    Stop,
+    SetVolume { volume: u16 },
+    // Meta operations
+    UpdateMetadata { track_id: u32, metadata: String },
+}
+
+impl OpenHomeOpQueue {
+    /// Push operation to the FIFO queue
+    pub fn push(&self, op: OpenHomeOp) {
+        self.queue.lock().unwrap().push(op);
+    }
+    
+    /// Push with priority (volume, play, stop - need fast response)
+    pub fn push_first(&self, op: OpenHomeOp) {
+        self.queue.lock().unwrap().push_front(op);
+    }
+    
+    /// Clear all pending operations (client can flush)
+    pub fn clear(&self) {
+        self.queue.lock().unwrap().clear();
+    }
+    
+    /// Worker thread consumes operations
+    fn worker_loop(&self) {
+        loop {
+            let op = self.queue.lock().unwrap().pop_front();
+            match op {
+                Some(op) => self.execute(op),
+                None => thread::sleep(Duration::from_millis(10)),
+            }
+        }
+    }
+}
+```
+
+**Benefits**:
+- UI non-bloquante (les operations sont lancées et exec en background)
+- Batching naturel (plusieurs operations sont executes en sequence)
+- Priorité via `push_first()` pour play/stop/volume
+- `clear()` permet d'annuler les operations en attente (ex: playlist changée)
+
+**Implémentation suggérée**:
+1. Créer `src/queue/openhome_op_queue.rs` avec la structure
+2. Intégrer dans `OpenHomeQueue` ou `OpenHomeRenderer`
+3. Thread de worker lancé au démarrage du control point
+
+---
+
+### OPT-3: Métadonnées en Tâche de Fond
+
+**Observation**: L'appli utilise-t-elle vraiment les métadonnées de la queue OpenHome, ou un cache local?
+
+Si le control-point maintient son propre cache (plus probable):
+- Les mises à jour de métadonnées peuvent être traitées en background
+- Pas besoin de sync immédiate des métadonnées
+
+**Solution**: Queue séparée pour les operations de métadonnées:
+
+```rust
+// Haute priorité (opérations critiques)
+let high_priority_queue: OpenHomeOpQueue;
+
+// Basse priorité (métadonnées)
+let metadata_queue: OpenHomeOpQueue;
+```
+
+**Implémentation**:
+1. Séparer les operations critiques (play/stop/seek/volume) de metadata
+2. Metadata update traités en background avec délais
+3. Le cache local du control-point est mis à jour indépendamment
+
+---
+
+### OPT-4: Connection Pooling HTTP
+
+Chaque appel SOAP crée une nouvelle connexion. Avec 1000 insertions:
+- Overhead TCP: ~10-50ms par appel
+- Total: 10-50 secondes overhead réseau
+
+**Solution**: Agent HTTP static avec connection reuse:
+
+```rust
+// soap_client.rs
+static HTTP_AGENT: Lazy<ureq::Agent> = Lazy::new(|| {
+    Agent::config_builder()
+        .timeout_global(Some(Duration::from_secs(30)))
+        .build()
+});
+```
+
+---
+
+## Plan d'Implémentation Proposé
+
+### Phase 1: Fast Path LCS (Priorité Haute)
+
+1. Ajouter `detect_sync_pattern()` dans `openhome.rs`
+2. Implémenter `append_only()` et `delete_from_beginning()`
+3. Tester avec playlists réelles
+
+### Phase 2: Queue FIFO Opérations (Priorité Haute)
+
+1. Créer `src/queue/openhome_op_queue.rs`
+2. Implémenter `push()`, `push_first()`, `clear()`
+3. Thread worker avec loop de consommation
+4. Intégrer dans `OpenHomeRenderer`
+
+### Phase 3: Séparation Métadonnées (Priorité Moyenne)
+
+1. Créer queue séparée pour metadata
+2. Implémenter batch processing
+
+### Phase 4: Connection Pooling (Priorité Basse)
+
+1. Modifier `soap_client.rs` pour agent static
+
+---
+
+## Questions pour Clarification
+
+1. **Cache Métadonnées**: Le control-point utilise-t-il vraiment les métadonnées de la queue OpenHome, ou maintient-il son propre cache qui est alimenté indépendamment?
+
+2. **Priorité des Opérations**: Pour `push_first()`, quelles opérations nécessitent une réponse rapide?
+   - Volume (immédiat)
+   - Play/Pause/Stop (immédiat)
+   - Seek (rapide)
+   - Insert (peut être différé)
+
+3. **Comportement en cas de conflit**: Si le client fait `clear()` et que le worker est en train d'exécuter une opération:
+   - Annuler l'opération en cours? ( risky - peut laisser le renderer dans un état inconsistent)
+   - Laisser finir l'opération en cours? (plus sur)
+
+---
+
+## Tests Recommandés
+
+```bash
+# Compiler
+cargo build -p pmocontrol
+
+# Benchmark LCS fast paths
+# - Cas: append 100 tracks to 900 = O(N)
+# - Cas: delete 100 from 900 = O(N)  
+# - Cas: reorder = O(N²) avec LCS
+```
+
+---
+
+*Plan mis à jour avec contre-propositions utilisateur*
+*Date: 2026-04-08*
--- a/Blackboard/Todo/enorme_playlist_step2.md
+++ b/Blackboard/Todo/enorme_playlist_step2.md
@@ -0,0 +1,235 @@
+# Optimisation Playlist OpenHome — Étape 2
+
+**Contexte**: Suite de `enorme_playlist.md`. Les optimisations de base (MAX_BATCH=256, LCS prefixe/suffixe, polling adaptatif, caches TTL) sont faites. Les lenteurs persistent sur les grandes playlists (~1000 titres). Les renderers Chromecast et UPnP sont moins affectés mais bénéficieront également de certaines optimisations.
+
+**Contrainte architecturale fondamentale**: La queue OpenHome est la **source de vérité unique**. Un miroir local persistent a été tenté et abandonné — impossible à maintenir en sync quand d'autres control points (BubbleUPnP, Linn, etc.) modifient la queue. Toute optimisation doit respecter cette contrainte.
+
+**Note sur le LCS**: `lcs_flags_optimized` (openhome.rs:869) gère déjà le cas dominant (préfixe/suffixe communs). Pour un append de 100 tracks à 900 existants, le LCS est O(1) — ce n'est pas le goulot. Le coût réel est les appels SOAP : connexions TCP × (RTT + handshake) et les `ReadList` pour reconstruire le snapshot.
+
+---
+
+## Analyse des Goulots Réels
+
+Pour un `sync_queue` "append 100 tracks à 900 existants" aujourd'hui :
+
+| Étape | Appels SOAP | Coût estimé |
+|-------|------------|-------------|
+| `id_array()` | 1 | ~5ms |
+| `read_list()` — 4 batches × 256 | 4 | ~20ms |
+| 100 × `insert()` | 100 | ~100 × (RTT + **TCP handshake**) |
+| **Total TCP handshakes** | 105 | **105 × 10-50ms = 1-5 secondes** |
+
+Les deux leviers : (1) éliminer les handshakes TCP, (2) éliminer les `ReadList` quand inutiles.
+
+---
+
+## Plan d'Implémentation
+
+### Phase 1 — Connection Pooling (1-2h, PRIORITÉ MAXIMALE)
+
+**Fichier**: `pmocontrol/src/soap_client.rs`
+
+**Problème**: lignes 65-72 créent un nouvel `ureq::Agent` à chaque appel SOAP = nouvelle connexion TCP à chaque fois.
+
+**Solution**: Agent statique partagé via `OnceLock`.
+
+```rust
+use std::sync::OnceLock;
+
+static SOAP_AGENT: OnceLock<ureq::Agent> = OnceLock::new();
+
+fn get_soap_agent() -> &'static ureq::Agent {
+    SOAP_AGENT.get_or_init(|| {
+        ureq::Agent::config_builder()
+            .http_status_as_error(false)
+            .timeout_global(Some(Duration::from_secs(30)))
+            .build()
+            .into()
+    })
+}
+```
+
+Dans `invoke_upnp_action_with_timeout()`, remplacer la construction de l'agent par :
+
+```rust
+// Cas normal : réutiliser l'agent partagé (keep-alive, connection pooling)
+// Cas custom timeout : agent dédié (rare — timeout global suffit en pratique)
+let agent_owned;
+let agent: &ureq::Agent = if timeout.is_some() {
+    agent_owned = ureq::Agent::config_builder()
+        .http_status_as_error(false)
+        .timeout_global(timeout)
+        .build()
+        .into();
+    &agent_owned
+} else {
+    get_soap_agent()
+};
+```
+
+**Vérifier** que `ureq::Agent` maintient bien un pool de connexions HTTP/1.1 keep-alive entre les appels (comportement documenté de ureq v3 — l'agent est conçu pour être réutilisé).
+
+**Impact**: Élimine les TCP handshakes répétés pour tous les renderers (OpenHome, UPnP, Chromecast). Pour 100 inserts : 99 handshakes économisés × 10-50ms = **1-5 secondes récupérées**.
+
+---
+
+### Phase 2 — Fast Path Session (2-3h, PRIORITÉ HAUTE)
+
+**Concept**: Sans miroir persistant (abandonné), on peut quand même éviter les `ReadList` dans le cas dominant en maintenant un état **éphémère de session** — valable uniquement entre deux `sync_queue` consécutifs, et invalidé dès qu'on détecte une incohérence.
+
+**Principe**: Après chaque `sync_queue`, mémoriser :
+- la liste d'IDs résultante (déjà dans `track_ids_cache` TTL 1s)
+- le `after_id` du dernier insert (pour pouvoir appender sans `id_array`)
+
+Au prochain `sync_queue`, tenter de détecter le pattern sans `ReadList` :
+
+```rust
+fn try_fast_path(&self, new_items: &[PlaybackItem]) -> FastPathResult {
+    // Récupérer les IDs actuels (cache ou 1 appel id_array)
+    let current_ids = self.track_ids()?;
+    let current_len = current_ids.len();
+    let new_len = new_items.len();
+
+    // Fast path 1: append only
+    // Condition: new_items a plus d'items, et les current_len premiers de new_items
+    // ont les mêmes didl_id que les items actuels (vérifiable depuis id_array + metadata_cache local)
+    if new_len > current_len {
+        let prefix_matches = self.check_prefix_matches(&current_ids, &new_items[..current_len]);
+        if prefix_matches {
+            return FastPathResult::AppendOnly { items: &new_items[current_len..] };
+        }
+    }
+
+    // Fast path 2: delete from end
+    if new_len < current_len {
+        let prefix_matches = self.check_prefix_matches(&current_ids[..new_len], new_items);
+        if prefix_matches {
+            let to_delete = &current_ids[new_len..];
+            return FastPathResult::DeleteFromEnd { ids: to_delete };
+        }
+    }
+
+    // Cas général: fallback ReadList + LCS
+    FastPathResult::NeedFullSync
+}
+```
+
+**`check_prefix_matches`** : compare `current_ids[i]` avec `new_items[i]` en utilisant le `metadata_cache` local (déjà en mémoire) pour résoudre les URIs/didl_ids des IDs connus. Si un ID n'est pas en cache → fast path impossible → fallback.
+
+**Clé**: Cette vérification utilise uniquement le `metadata_cache` local (HashMap en mémoire, nano-secondes) et `id_array()` (déjà caché TTL 1s). Zéro appel `ReadList` dans le cas heureux. Si la vérification échoue (incohérence détectée, cache manquant) → fallback propre vers `ReadList` + LCS, source de vérité OpenHome préservée.
+
+**Fichier**: `pmocontrol/src/queue/openhome.rs`, ajouter `try_fast_path()` et l'intégrer en début de `sync_queue()`.
+
+---
+
+### Phase 3 — Queue FIFO Async (8-12h, PRIORITÉ MOYENNE)
+
+**Prérequis**: Phases 1 et 2 complétées.
+
+**Concept**: Exécuter les opérations SOAP dans un thread dédié pour rendre `sync_queue()` non-bloquant du point de vue de l'appelant.
+
+**Contrainte technique**: Les `insert()` sont chaînés — chaque appel retourne un `new_id` utilisé comme `after_id` du suivant. Le worker doit maintenir cet état interne.
+
+**Fichier à créer**: `pmocontrol/src/queue/openhome_op_queue.rs`
+
+```rust
+pub enum OpenHomeOp {
+    /// Insert séquentiel — after_id géré en interne (last_inserted_id)
+    InsertAtEnd { uri: String, metadata: String, didl_id: String },
+    /// Insert après un ID connu (ex: après le pivot)
+    InsertAfter { after_id: u32, uri: String, metadata: String, didl_id: String },
+    DeleteId { track_id: u32 },
+    DeleteAll,
+    SeekId { id: u32 },
+    Play,
+    Pause,
+    Stop,
+    SetVolume { volume: u16 },
+}
+
+pub struct OpenHomeOpQueue {
+    sender: mpsc::Sender<OpenHomeOp>,
+    last_error: Arc<Mutex<Option<ControlPointError>>>,
+    completion: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl OpenHomeOpQueue {
+    pub fn push(&self, op: OpenHomeOp) { ... }
+    /// Opérations critiques passent devant (play/stop/volume)
+    pub fn push_priority(&self, op: OpenHomeOp) { ... }
+    /// Vider la file d'attente (ex: nouvelle playlist demandée avant fin de sync)
+    pub fn clear_pending(&self) { ... }
+    /// Attendre que toutes les opérations soient exécutées
+    pub fn wait_completion(&self) { ... }
+    /// Récupérer la dernière erreur (non-bloquant)
+    pub fn take_error(&self) -> Option<ControlPointError> { ... }
+}
+```
+
+**Comportement en cas d'erreur**: vider la file d'attente, signaler l'erreur via `last_error`, invalider les caches OpenHome (forcer re-sync depuis source de vérité au prochain appel).
+
+**Comportement en cas de `clear_pending()` pendant exécution**: laisser l'opération en cours se terminer (plus sûr — évite de laisser le renderer dans un état inconsistant), vider le reste.
+
+**Intégration dans `OpenHomeQueue`**: remplacer les appels directs `playlist_client.insert()` / `playlist_client.delete_id()` par des `op_queue.push()`. Les opérations qui ont besoin d'une réponse synchrone (ex: `current_track()`, `queue_snapshot()`) continuent d'appeler directement le `playlist_client` — mais doivent d'abord attendre la complétion de la file (`wait_completion()`).
+
+---
+
+### Phase 4 — Throttle des replace_item (2-3h, PRIORITÉ BASSE)
+
+**Contexte**: `replace_item()` (openhome.rs:1315) fait `delete_id` + `insert` pour mettre à jour une piste. Sur un stream radio qui change de morceau, la durée est mise à jour fréquemment → paires SOAP inutiles car le `metadata_cache` local est déjà la source pour l'UI.
+
+**Solution**: Ne pas envoyer le `delete_id` + `insert` OpenHome si une mise à jour pour ce `track_id` a déjà été envoyée dans les N dernières secondes. Le `metadata_cache` local est mis à jour immédiatement (pour l'UI), et l'opération OpenHome est différée ou ignorée.
+
+```rust
+fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
+    let track_id = self.track_ids()?[index];
+
+    // Toujours mettre à jour le cache local immédiatement (pour l'UI)
+    self.cache_metadata(track_id, item.metadata.clone());
+
+    // Throttle: si replace OpenHome récent pour ce track, sauter l'opération SOAP
+    if self.is_recent_replace(track_id, Duration::from_secs(5)) {
+        return Ok(());
+    }
+    self.mark_replace_time(track_id);
+
+    // Opération SOAP (delete + insert)
+    // ... code existant ...
+}
+```
+
+Ajouter `last_replace_times: Mutex<HashMap<u32, SystemTime>>` dans `OpenHomeQueue`.
+
+---
+
+## Ordre d'Implémentation
+
+```
+Phase 1 → mesurer gain TCP → Phase 2 → mesurer gain ReadList → Phase 3 → Phase 4
+```
+
+Tester chaque phase avec des playlists réelles (~1000 tracks) avant de poursuivre. Ne pas combiner les phases pour pouvoir isoler les régressions.
+
+## Tests
+
+```bash
+# Phase 1 — vérifier connexions TCP réutilisées
+# tcpdump -i lo port 60000 -c 200  (ou port du renderer)
+# Avant: SYN à chaque appel SOAP
+# Après: SYN unique, flux keep-alive
+
+# Phase 2 — vérifier fast path activé
+# RUST_LOG=debug cargo run ... 2>&1 | grep "fast path"
+# Cas append 100 → "fast path: AppendOnly, 100 inserts"
+# Cas delete 100 → "fast path: DeleteFromEnd, 100 deletes"
+# Cas reorder   → "fast path: NeedFullSync, falling back to ReadList+LCS"
+
+# Phase 3 — vérifier non-blocage
+# sync_queue() doit retourner en <1ms (les 100 inserts continuent en background)
+```
+
+---
+
+*Contrainte architecturale intégrée: miroir local abandonné (désynchronisation avec autres control points). Toutes les phases respectent OpenHome comme source de vérité unique.*
+
+*Date: 2026-04-08*
--- a/Blackboard/Todo/enorme_playlist_step3.md
+++ b/Blackboard/Todo/enorme_playlist_step3.md
@@ -0,0 +1,642 @@
+** Ce travail devra être réalisé en suivant scrupuleusement les consignes listées dans le fichier [@Rules_optimal.md](file:///Users/coissac/Sync/maison/Petite_maisons/src/pmomusic/Blackboard/Rules_optimal.md) **
+
+# Async Queue Refresh — Étape 3
+
+**Contexte**: `refresh_attached_queue_for()` dans `control_point.rs` est appelé de 3 endroits
+et bloque son thread pendant toute la synchronisation (browse media server + 100+ opérations
+SOAP/mémoire). L'objectif est de factoriser le mécanisme async au niveau de la couche queue
+(`MusicQueue`), qui est déjà l'abstraction agnostique du backend. `control_point.rs` ne doit
+plus connaître les threads ni les tokens d'annulation.
+
+**Principe architectural**: la couche queue sait *comment* syncer (mémoire ou SOAP) et donc
+aussi *comment* annuler et *quand* signaler que la lecture peut démarrer. `control_point.rs`
+sait seulement *quoi* syncer (browse + conversion PlaybackItem). Les deux responsabilités
+restent séparées.
+
+---
+
+## Vue d'ensemble des changements
+
+```
+AVANT
+  control_point.rs
+    refresh_attached_queue_for()
+      → browse()
+      → sync_queue(items)   ← bloquant 1-5s
+
+APRÈS
+  control_point.rs
+    do_queue_refresh_work()  ← interne, fait le browse + conversion
+  MusicQueue (couche queue)
+    schedule_sync(items, callbacks)  ← non-bloquant, retourne immédiatement
+      → thread "queue-sync-{renderer_id}"
+           → QueueBackend::sync_queue(items, cancel_token, on_ready)
+```
+
+---
+
+## Fichiers à modifier / créer
+
+| Fichier | Action |
+|---------|--------|
+| `pmocontrol/src/errors.rs` | Ajouter variante `SyncCancelled` |
+| `pmocontrol/src/queue/backend.rs` | Modifier signature `sync_queue()` |
+| `pmocontrol/src/queue/interne.rs` | Adapter signature `sync_queue()` |
+| `pmocontrol/src/queue/openhome.rs` | Adapter + points de vérification cancel + on_ready |
+| `pmocontrol/src/queue/music_queue.rs` | Ajouter champs async + méthode `schedule_sync()` |
+| `pmocontrol/src/queue/mod.rs` | Exporter `SyncScheduleOutcome` |
+| `pmocontrol/src/model.rs` | Ajouter événements `QueueReadyToPlay`, `QueueSyncCancelled` |
+| `pmocontrol/src/sse.rs` | Sérialiser les deux nouveaux événements |
+| `pmocontrol/src/control_point.rs` | Remplacer les 3 call sites bloquants |
+
+---
+
+## Étape 1 — Nouvelle variante d'erreur (`errors.rs`)
+
+**Fichier**: `pmocontrol/src/errors.rs`
+
+Ajouter après la ligne 51 (`ControlPoint`) :
+
+```rust
+#[error("Queue sync cancelled (superseded by a newer request)")]
+SyncCancelled,
+```
+
+Cette variante est retournée par `sync_queue()` quand le `cancel_token` passe à `true`.
+Elle est **non-fatale** — le coordinator la traite comme un comportement normal, pas une
+erreur à logger en `warn!`.
+
+---
+
+## Étape 2 — Modifier la signature de `sync_queue()` dans le trait (`backend.rs`)
+
+**Fichier**: `pmocontrol/src/queue/backend.rs`, ligne 110
+
+```rust
+// AVANT
+fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError>;
+
+// APRÈS
+use std::sync::{Arc, atomic::AtomicBool};
+
+fn sync_queue(
+    &mut self,
+    items: Vec<PlaybackItem>,
+    cancel_token: &Arc<AtomicBool>,
+    on_ready: Option<Box<dyn FnOnce() + Send>>,
+) -> Result<(), ControlPointError>;
+```
+
+**Sémantique des paramètres** :
+- `cancel_token` : si `true` au moment d'une opération, retourner `Err(SyncCancelled)` immédiatement
+- `on_ready` : callback one-shot appelé quand la lecture peut démarrer (voir logique ci-dessous)
+
+---
+
+## Étape 3 — Adapter `InternalQueue::sync_queue()` (`interne.rs`)
+
+**Fichier**: `pmocontrol/src/queue/interne.rs`
+
+Trouver la méthode `sync_queue()` et adapter la signature. Le corps reste identique,
+avec deux ajouts :
+
+**1. Vérification du pivot (early start)** : si une piste est en cours de lecture
+(un `current_index` est défini dans le snapshot courant), appeler `on_ready` immédiatement
+avant toute opération — la piste courante sera préservée.
+
+**2. Si pas de pivot** (queue vide ou aucune piste en cours) : appeler `on_ready` après
+avoir inséré le premier item.
+
+**3. Vérification cancel** : après chaque item inséré/supprimé (en pratique `InternalQueue`
+est rapide mais le principe doit être cohérent) :
+
+```rust
+fn sync_queue(
+    &mut self,
+    items: Vec<PlaybackItem>,
+    cancel_token: &Arc<AtomicBool>,
+    mut on_ready: Option<Box<dyn FnOnce() + Send>>,
+) -> Result<(), ControlPointError> {
+    use std::sync::atomic::Ordering::SeqCst;
+
+    // Early start si pivot présent
+    let has_current = self.current_index()?.is_some();
+    if has_current {
+        if let Some(f) = on_ready.take() { f(); }
+    }
+
+    // ... logique existante de sync_queue() ...
+    // Dans la boucle d'insertions, après le 1er insert :
+    if on_ready.is_some() {
+        if let Some(f) = on_ready.take() { f(); }
+    }
+    // Après chaque opération :
+    if cancel_token.load(SeqCst) {
+        return Err(ControlPointError::SyncCancelled);
+    }
+
+    Ok(())
+}
+```
+
+---
+
+## Étape 4 — Adapter `OpenHomeQueue::sync_queue()` (`openhome.rs`)
+
+**Fichier**: `pmocontrol/src/queue/openhome.rs`
+
+### 4.1 Signature (ligne ~1277)
+
+```rust
+fn sync_queue(
+    &mut self,
+    items: Vec<PlaybackItem>,
+    cancel_token: &Arc<AtomicBool>,
+    mut on_ready: Option<Box<dyn FnOnce() + Send>>,
+) -> Result<(), ControlPointError>
+```
+
+### 4.2 Early start — logique pivot
+
+Au début de `sync_queue()`, **avant** toute opération SOAP, détecter si un pivot est présent :
+
+```rust
+// Après la récupération du snapshot (ligne ~1323), avant les branches if/else :
+let has_pivot = playing_info.is_some();
+if has_pivot {
+    // Le pivot sera préservé — on peut démarrer la lecture immédiatement
+    if let Some(f) = on_ready.take() { f(); }
+}
+```
+
+Si pas de pivot (nouvelle playlist via `delete_all` + inserts depuis 0) : appeler `on_ready`
+après le **1er insert réussi** dans `replace_queue()` et dans `replace_queue_standard_lcs()`.
+
+### 4.3 Points de vérification cancel
+
+Ajouter `if cancel_token.load(SeqCst) { return Err(SyncCancelled); }` aux endroits suivants :
+
+- Dans `delete_marked_items()` (ligne ~458) : après chaque `delete_id_if_exists()`
+- Dans `rebuild_playlist_section()` (ligne ~494) : après chaque `insert()`
+- Dans `replace_queue_preserve_current()` (ligne ~419) : après chaque `delete_id_if_exists()` et `insert()`
+- Dans `replace_queue_standard_lcs()` (ligne ~693-745) : après chaque delete et insert
+- Dans `replace_queue()` (ligne ~1118) : après chaque insert dans la boucle
+- Dans le fast path `AppendOnly` (ligne ~1318) : après chaque insert
+- Dans le fast path `DeleteFromEnd` (ligne ~1336) : après chaque delete
+
+### 4.4 Propagation du cancel_token aux helpers
+
+Les méthodes helper privées qui font des boucles doivent recevoir le token :
+
+```rust
+fn delete_marked_items(
+    &mut self,
+    old_ids: &[u32],
+    keep_flags: &[bool],
+    position_label: &str,
+    cancel_token: &Arc<AtomicBool>,
+) -> Result<(), ControlPointError>
+
+fn rebuild_playlist_section(
+    &mut self,
+    // ... params existants ...
+    cancel_token: &Arc<AtomicBool>,
+    on_ready: &mut Option<Box<dyn FnOnce() + Send>>,
+) -> Result<u32, ControlPointError>
+```
+
+---
+
+## Étape 5 — Adapter `MusicQueue` (dispatch enum) (`music_queue.rs`)
+
+**Fichier**: `pmocontrol/src/queue/music_queue.rs`
+
+### 5.1 Adapter le dispatch `sync_queue()` (ligne ~98)
+
+```rust
+fn sync_queue(
+    &mut self,
+    items: Vec<PlaybackItem>,
+    cancel_token: &Arc<AtomicBool>,
+    on_ready: Option<Box<dyn FnOnce() + Send>>,
+) -> Result<(), ControlPointError> {
+    match self {
+        MusicQueue::Internal(q) => q.sync_queue(items, cancel_token, on_ready),
+        MusicQueue::OpenHome(q) => q.sync_queue(items, cancel_token, on_ready),
+    }
+}
+```
+
+### 5.2 Ajouter l'état async dans `MusicQueue`
+
+`MusicQueue` passe de simple enum de dispatch à une struct qui **encapsule** l'enum backend
+et l'état de synchronisation async :
+
+```rust
+// AVANT
+pub enum MusicQueue {
+    Internal(InternalQueue),
+    OpenHome(OpenHomeQueue),
+}
+
+// APRÈS
+pub struct MusicQueue {
+    backend: MusicQueueBackend,
+    // État async de synchronisation
+    sync_in_progress: Arc<AtomicBool>,
+    sync_pending: Arc<AtomicBool>,
+    sync_cancel_token: Arc<AtomicBool>,
+}
+
+// L'enum devient privée
+enum MusicQueueBackend {
+    Internal(InternalQueue),
+    OpenHome(OpenHomeQueue),
+}
+```
+
+**Note**: le changement de `enum` en `struct` implique de mettre à jour toutes les
+utilisations de `MusicQueue::Internal(...)` et `MusicQueue::OpenHome(...)` dans le reste
+du code (essentiellement `music_queue.rs` lui-même et `mod.rs`). Les callers externes
+utilisent `MusicQueue` via `QueueBackend` et `QueueFromRendererInfo` — ils ne sont pas
+impactés si l'API publique est préservée.
+
+### 5.3 Enum résultat et méthode `schedule_sync()`
+
+```rust
+pub enum SyncScheduleOutcome {
+    /// Thread spawné, sync en cours.
+    Scheduled,
+    /// Sync déjà en cours — annulée et nouvelle sync programmée en pending.
+    AlreadyRunning,
+}
+```
+
+```rust
+impl MusicQueue {
+    /// Lance une synchronisation asynchrone de la queue.
+    ///
+    /// - Si aucune sync n'est en cours : spawne un thread, retourne `Scheduled`.
+    /// - Si une sync est en cours : l'annule, note une sync pending, retourne `AlreadyRunning`.
+    ///   Le thread en cours finira l'opération courante, détectera le cancel, puis
+    ///   relancera la sync avec les nouveaux items via `pending_items_fn`.
+    ///
+    /// `pending_items_fn` : closure appelée dans le worker pour re-fetcher les items
+    ///   en cas de pending. Elle doit être Send + 'static car elle s'exécute dans un thread.
+    ///
+    /// `on_ready` : appelé dès que la lecture peut démarrer (pivot préservé ou 1er insert).
+    ///
+    /// `renderer_id` : utilisé uniquement pour nommer le thread de travail.
+    pub fn schedule_sync(
+        &self,  // &self car l'état async est derrière Arc<AtomicBool>
+        renderer_id: &str,
+        items: Vec<PlaybackItem>,
+        pending_items_fn: Box<dyn Fn() -> Result<Vec<PlaybackItem>, ControlPointError> + Send + 'static>,
+        on_ready: Option<Box<dyn FnOnce() + Send + 'static>>,
+    ) -> SyncScheduleOutcome
+```
+
+**Problème de `&mut self` vs `&self`** : `sync_queue()` dans le trait prend `&mut self`
+car les backends mutent leur état. Mais `schedule_sync()` veut spawner un thread qui détient
+le backend. Solution : le backend est déjà derrière `Arc<Mutex<MusicQueue>>` dans
+`MusicRenderer` (ligne 124 de musicrenderer.rs — c'est le `queue` field). Le thread worker
+clone cet `Arc` et acquiert le lock pour appeler `sync_queue()`.
+
+**Signature révisée** :
+
+```rust
+/// Doit être appelé avec un Arc<Mutex<Self>> pour permettre le spawn du thread worker.
+pub fn schedule_sync(
+    queue_arc: &Arc<Mutex<MusicQueue>>,
+    renderer_id: &str,
+    items: Vec<PlaybackItem>,
+    pending_items_fn: Box<dyn Fn() -> Result<Vec<PlaybackItem>, ControlPointError> + Send + 'static>,
+    on_ready: Option<Box<dyn FnOnce() + Send + 'static>>,
+) -> SyncScheduleOutcome {
+    use std::sync::atomic::Ordering::SeqCst;
+
+    let (sync_in_progress, sync_pending, sync_cancel_token) = {
+        let q = queue_arc.lock().unwrap();
+        (
+            Arc::clone(&q.sync_in_progress),
+            Arc::clone(&q.sync_pending),
+            Arc::clone(&q.sync_cancel_token),
+        )
+    };
+
+    if sync_in_progress.swap(true, SeqCst) {
+        // Sync en cours : annuler et noter pending
+        sync_cancel_token.store(true, SeqCst);
+        sync_pending.store(true, SeqCst);
+        return SyncScheduleOutcome::AlreadyRunning;
+    }
+
+    // Pas de sync en cours : initialiser et spawner
+    sync_cancel_token.store(false, SeqCst);
+    sync_pending.store(false, SeqCst);
+
+    let queue_arc = Arc::clone(queue_arc);
+    let thread_name = format!("queue-sync-{}", renderer_id);
+
+    thread::Builder::new()
+        .name(thread_name)
+        .spawn(move || {
+            // Guard: libère in_progress à la sortie même en cas de panic
+            struct Guard(Arc<AtomicBool>);
+            impl Drop for Guard {
+                fn drop(&mut self) { self.0.store(false, SeqCst); }
+            }
+            let _guard = Guard(Arc::clone(&sync_in_progress));
+
+            let mut current_items = items;
+            let mut current_on_ready = Some(on_ready);
+
+            loop {
+                sync_pending.store(false, SeqCst);
+                sync_cancel_token.store(false, SeqCst);
+
+                let result = {
+                    let mut q = queue_arc.lock().unwrap();
+                    q.backend.sync_queue(
+                        current_items,
+                        &sync_cancel_token,
+                        current_on_ready.take().flatten(),
+                    )
+                };
+
+                match result {
+                    Err(ControlPointError::SyncCancelled) => {
+                        // Annulé normalement — vérifier si pending
+                    }
+                    Err(e) => {
+                        warn!("queue-sync error: {}", e);
+                    }
+                    Ok(()) => {}
+                }
+
+                if !sync_pending.load(SeqCst) {
+                    break; // Pas de nouvelle sync en attente → terminer
+                }
+
+                // Nouvelle sync demandée pendant l'exécution → re-fetcher et relancer
+                match pending_items_fn() {
+                    Ok(new_items) => {
+                        current_items = new_items;
+                        current_on_ready = Some(None); // pas de on_ready pour les re-syncs
+                    }
+                    Err(e) => {
+                        warn!("queue-sync pending re-fetch error: {}", e);
+                        break;
+                    }
+                }
+            }
+            // _guard libère sync_in_progress = false
+        })
+        .expect("Failed to spawn queue-sync thread");
+
+    SyncScheduleOutcome::Scheduled
+}
+```
+
+---
+
+## Étape 6 — Nouveaux événements SSE
+
+### 6.1 `model.rs`
+
+Localiser l'enum `RendererEvent` et ajouter :
+
+```rust
+/// Émis dès que la queue peut être lue (pivot préservé ou 1er track inséré).
+QueueReadyToPlay {
+    id: DeviceId,
+},
+/// Émis quand une sync est annulée car une nouvelle a été demandée.
+QueueSyncCancelled {
+    id: DeviceId,
+},
+```
+
+### 6.2 `sse.rs`
+
+Localiser le match de sérialisation des `RendererEvent` et ajouter les deux variantes.
+Suivre le pattern existant de `QueueRefreshing` (ligne ~152) :
+
+```rust
+RendererEvent::QueueReadyToPlay { id } => {
+    // sérialiser avec type = "queue_ready_to_play"
+}
+RendererEvent::QueueSyncCancelled { id } => {
+    // sérialiser avec type = "queue_sync_cancelled"
+}
+```
+
+---
+
+## Étape 7 — Modifier `control_point.rs`
+
+### 7.1 Extraire la logique de browse
+
+Renommer `refresh_attached_queue_for()` en deux fonctions :
+
+**`fetch_queue_items_for()`** (nouvelle, interne) : fait le browse + conversion, retourne
+`Vec<PlaybackItem>`. C'est la `pending_items_fn` passée à `schedule_sync()`.
+
+**`schedule_queue_refresh_for()`** (remplace l'ancienne) : appelle `fetch_queue_items_for()`,
+puis `MusicQueue::schedule_sync()`.
+
+```rust
+fn fetch_queue_items_for(
+    registry: &Arc<RwLock<DeviceRegistry>>,
+    renderer_id: &DeviceId,
+) -> Result<Vec<PlaybackItem>, ControlPointError> {
+    // Browse media server + conversion PlaybackItem
+    // (logique actuellement dans refresh_attached_queue_for() lignes ~1593-1670)
+}
+
+fn schedule_queue_refresh_for(
+    registry: &Arc<RwLock<DeviceRegistry>>,
+    renderer_id: &DeviceId,
+    event_bus: &RendererEventBus,
+    auto_play_cb: Option<Box<dyn FnOnce(&DeviceId) -> Result<(), ControlPointError> + Send + 'static>>,
+) -> SyncScheduleOutcome {
+    let items = match fetch_queue_items_for(registry, renderer_id) {
+        Ok(items) => items,
+        Err(e) => { warn!(...); return SyncScheduleOutcome::Scheduled; /* ou erreur */ }
+    };
+
+    // on_ready : déclenche auto_play si demandé + émet QueueReadyToPlay SSE
+    let rid = renderer_id.clone();
+    let bus = event_bus.clone();
+    let on_ready: Option<Box<dyn FnOnce() + Send + 'static>> = Some(Box::new(move || {
+        bus.broadcast(RendererEvent::QueueReadyToPlay { id: rid.clone() });
+        if let Some(cb) = auto_play_cb {
+            if let Err(e) = cb(&rid) {
+                warn!("auto-play callback failed: {}", e);
+            }
+        }
+    }));
+
+    // pending_items_fn : re-fetcher depuis le media server si pending
+    let registry2 = Arc::clone(registry);
+    let rid2 = renderer_id.clone();
+    let pending_fn = Box::new(move || fetch_queue_items_for(&registry2, &rid2));
+
+    // Récupérer l'Arc<Mutex<MusicQueue>> du renderer depuis le registry
+    let queue_arc = {
+        let reg = registry.read().unwrap();
+        reg.get_renderer_queue_arc(renderer_id)? // méthode à ajouter dans DeviceRegistry
+    };
+
+    // Émettre QueueRefreshing avant de lancer
+    event_bus.broadcast(RendererEvent::QueueRefreshing { id: renderer_id.clone() });
+
+    let outcome = MusicQueue::schedule_sync(&queue_arc, &renderer_id.0, items, pending_fn, on_ready);
+
+    if matches!(outcome, SyncScheduleOutcome::AlreadyRunning) {
+        event_bus.broadcast(RendererEvent::QueueSyncCancelled { id: renderer_id.clone() });
+    }
+
+    outcome
+}
+```
+
+### 7.2 Call site 1 — thread "cp-media-server-event-worker" (l.270)
+
+```rust
+// AVANT
+let _ = refresh_attached_queue_for(&registry, &renderer_id, &event_bus, None);
+// APRÈS
+schedule_queue_refresh_for(&registry, &renderer_id, &event_bus, None);
+```
+
+### 7.3 Call site 2 — thread "cp-playlist-periodic-refresh" (l.340)
+
+```rust
+// AVANT
+let _ = refresh_attached_queue_for(&registry_for_periodic, &renderer_id, &event_bus_for_periodic, None);
+// APRÈS
+schedule_queue_refresh_for(&registry_for_periodic, &renderer_id, &event_bus_for_periodic, None);
+```
+
+### 7.4 Call site 3 — `attach_queue_to_playlist_async()` (l.1264)
+
+```rust
+pub async fn attach_queue_to_playlist_async(
+    &self, renderer_id: &DeviceId, server_id: &DeviceId, container_id: &str, auto_play: bool,
+) -> Result<(), ControlPointError> {
+    // 1. Enregistrer la liaison (synchrone, ~1ms)
+    self.registry.write().unwrap()
+        .set_playlist_binding(renderer_id, server_id, container_id);
+
+    // 2. Construire le callback auto-play si demandé
+    let cp = self.clone();
+    let rid = renderer_id.clone();
+    let auto_play_cb: Option<Box<dyn FnOnce(&DeviceId) -> Result<(), ControlPointError> + Send + 'static>> =
+        if auto_play {
+            Some(Box::new(move |id| cp.play_current_from_queue(id)))
+        } else {
+            None
+        };
+
+    // 3. Lancer le refresh async — retourne immédiatement
+    schedule_queue_refresh_for(&self.registry, renderer_id, &self.event_bus, auto_play_cb);
+
+    Ok(())  // La webapp sera notifiée via SSE (QueueRefreshing → QueueReadyToPlay → QueueUpdated)
+}
+```
+
+### 7.5 Fin de sync — émettre `QueueUpdated`
+
+L'événement `QueueUpdated` (avec `queue_length`) est actuellement émis à la ligne ~1718
+dans `refresh_attached_queue_for()`. Il doit être émis à la fin du worker thread dans
+`MusicQueue::schedule_sync()`, après le `sync_queue()` réussi.
+
+Passer un `on_complete` callback à `schedule_sync()` (en plus de `on_ready`) :
+
+```rust
+pub fn schedule_sync(
+    queue_arc: &Arc<Mutex<MusicQueue>>,
+    renderer_id: &str,
+    items: Vec<PlaybackItem>,
+    pending_items_fn: Box<dyn Fn() -> Result<Vec<PlaybackItem>, ControlPointError> + Send + 'static>,
+    on_ready: Option<Box<dyn FnOnce() + Send + 'static>>,
+    on_complete: Box<dyn Fn(usize) + Send + 'static>,  // NOUVEAU — reçoit queue_length
+) -> SyncScheduleOutcome
+```
+
+Dans le worker, après `Ok(())` du `sync_queue()` :
+
+```rust
+Ok(()) => {
+    let queue_len = queue_arc.lock().unwrap().len().unwrap_or(0);
+    on_complete(queue_len);
+}
+```
+
+Dans `schedule_queue_refresh_for()` :
+
+```rust
+let bus3 = event_bus.clone();
+let rid3 = renderer_id.clone();
+let on_complete = Box::new(move |queue_len: usize| {
+    bus3.broadcast(RendererEvent::QueueUpdated {
+        id: rid3.clone(),
+        queue_length: queue_len,
+    });
+});
+```
+
+---
+
+## Étape 8 — Accès à `Arc<Mutex<MusicQueue>>` depuis le registry
+
+`schedule_queue_refresh_for()` a besoin d'accéder à l'`Arc<Mutex<MusicQueue>>` du renderer.
+Localiser dans `DeviceRegistry` comment les renderers et leurs queues sont stockés, et ajouter
+une méthode :
+
+```rust
+pub fn get_renderer_queue_arc(
+    &self,
+    renderer_id: &DeviceId,
+) -> Result<Arc<Mutex<MusicQueue>>, ControlPointError>
+```
+
+(Ou équivalent selon la structure réelle du registry.)
+
+---
+
+## Ordre d'implémentation
+
+```
+Étape 1 (errors.rs)          ← 5 min
+Étape 2 (backend.rs)         ← 10 min, casse la compilation → à faire avant les autres
+Étape 3 (interne.rs)         ← 30 min
+Étape 4 (openhome.rs)        ← 1-2h (nombreux points de vérification cancel)
+Étape 5 (music_queue.rs)     ← 2-3h (changement struct + schedule_sync)
+Étape 6 (model.rs + sse.rs)  ← 30 min
+Étape 7 (control_point.rs)   ← 1h
+Étape 8 (registry)           ← 30 min selon la structure
+```
+
+Après l'étape 2, `cargo build` cassera jusqu'à l'étape 5 incluse — c'est attendu.
+Faire les étapes 3, 4, 5 dans la même session sans interrompre.
+
+## Tests
+
+```bash
+cargo build -p pmocontrol
+
+# Vérifier les scénarios :
+# 1. Attach playlist → QueueRefreshing SSE immédiat, QueueReadyToPlay après 1er insert,
+#    QueueUpdated après fin complète
+# 2. Attach 2e playlist pendant sync en cours → QueueSyncCancelled + nouveau refresh repart
+# 3. Piste en cours de lecture pendant sync → QueueReadyToPlay immédiat (pivot préservé)
+# 4. Refresh périodique (60s) ne bloque plus son thread
+
+RUST_LOG=debug cargo run 2>&1 | grep -E "queue.sync|SyncCancelled|Scheduled|AlreadyRunning|on_ready|on_complete"
+```
+
+---
+
+*Date: 2026-04-09*
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,7 +4,7 @@ version = 4

 [[package]]
 name = "PMOMusic"
-version = "0.3.39"
+version = "0.3.41"
 dependencies = [
 "axum 0.8.7",
 "console-subscriber",
--- a/PMOMusic/Cargo.toml
+++ b/PMOMusic/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "PMOMusic"
-version = "0.3.40"
+version = "0.3.41"
 edition = "2024"

 [dependencies]
--- a/pmoapp/webapp/package-lock.json
+++ b/pmoapp/webapp/package-lock.json
@@ -1609,9 +1609,9 @@
      "license": "MIT"
    },
    "node_modules/vite": {
-      "version": "7.3.1",
-      "resolved": "https://registry.npmjs.org/vite/-/vite-7.3.1.tgz",
-      "integrity": "sha512-w+N7Hifpc3gRjZ63vYBXA56dvvRlNWRczTdmCBBa+CotUzAPf5b7YMdMR/8CQoeYE5LX3W4wj6RYTgonm1b9DA==",
+      "version": "7.3.2",
+      "resolved": "https://registry.npmjs.org/vite/-/vite-7.3.2.tgz",
+      "integrity": "sha512-Bby3NOsna2jsjfLVOHKes8sGwgl4TT0E6vvpYgnAYDIF/tie7MRaFthmKuHx1NSXjiTueXH3do80FMQgvEktRg==",
      "dev": true,
      "license": "MIT",
      "dependencies": {
--- a/pmoapp/webapp/src/components/unified/ServerDrawer.vue
+++ b/pmoapp/webapp/src/components/unified/ServerDrawer.vue
@@ -51,6 +51,7 @@ const searchInput = ref('');
 const isSearchMode = computed(() => searchQuery.value !== '');

 async function handleSearch() {
+    console.log('[ServerDrawer] handleSearch called, currentServer:', currentServer.value?.id, 'searchInput:', searchInput.value);
    if (!currentServer.value || !searchInput.value.trim()) return;
    await searchServer(currentServer.value.id, searchInput.value.trim());
 }
--- a/pmoapp/webapp/src/composables/useMediaServers.ts
+++ b/pmoapp/webapp/src/composables/useMediaServers.ts
@@ -216,6 +216,7 @@ export function useMediaServers() {

  // Recherche dans un serveur
  async function searchServer(serverId: string, query: string) {
+    console.log(`[useMediaServers] searchServer called: serverId=${serverId}, query=${query}`);
    if (!query.trim()) {
      searchResults.value = null
      searchQuery.value = ''
@@ -226,8 +227,10 @@ export function useMediaServers() {
      loading.value = true
      error.value = null
      searchQuery.value = query
+      console.log(`[useMediaServers] Calling API searchServer for server ${serverId}`);

      const data = await api.searchServer(serverId, query)
+      console.log(`[useMediaServers] Search returned ${data.entries.length} entries, total=${data.total_count}`);
      searchResults.value = {
        container_id: 'search',
        entries: data.entries,
--- a/pmocontrol/src/control_point.rs
+++ b/pmocontrol/src/control_point.rs
@@ -26,7 +26,7 @@ use crate::openapi::{
    CurrentTrackMetadata, FullRendererSnapshot, QueueItem, QueueSnapshotView, RendererBindingView,
    RendererStateView,
 };
-use crate::queue::{EnqueueMode, PlaybackItem, QueueSnapshot};
+use crate::queue::{EnqueueMode, PlaybackItem, QueueSnapshot, SyncScheduleOutcome};
 use crate::registry::DeviceRegistry;

 /// Control point minimal :
@@ -267,19 +267,12 @@ impl ControlPoint {
                                    "Triggering queue refresh for bound playlist"
                                );

-                                if let Err(err) = refresh_attached_queue_for(
+                                let _ = schedule_queue_refresh_for(
                                    &registry_for_media_worker,
                                    &renderer_id,
                                    &event_bus_for_media_worker,
                                    None,
-                                ) {
-                                    warn!(
-                                        renderer = renderer_id.0.as_str(),
-                                        server = server_id.0.as_str(),
-                                        error = %err,
-                                        "Failed to refresh queue from playlist container"
-                                    );
-                                }
+                                );
                            }
                        }
                        MediaServerEvent::Online { server_id, info } => {
@@ -337,18 +330,12 @@ impl ControlPoint {
                            "Periodic refresh triggered for bound playlist"
                        );

-                        if let Err(err) = refresh_attached_queue_for(
+                        let _ = schedule_queue_refresh_for(
                            &registry_for_periodic,
                            &renderer_id,
                            &event_bus_for_periodic,
                            None,
-                        ) {
-                            warn!(
-                                renderer = renderer_id.0.as_str(),
-                                error = %err,
-                                "Periodic refresh failed for bound playlist"
-                            );
-                        }
+                        );
                    }
                }
            })?;
@@ -1182,19 +1169,25 @@ impl ControlPoint {
            binding.auto_play_on_refresh = auto_play;
            renderer.set_playlist_binding(Some(binding));

-            let mut auto_start_cb = |rid: &DeviceId| self.play_current_from_queue(rid);
-            let callback: Option<&mut dyn FnMut(&DeviceId) -> Result<(), ControlPointError>> =
+            let callback: Option<Box<dyn FnOnce(&DeviceId) -> Result<(), ControlPointError> + Send + 'static>> =
                if auto_play {
-                    Some(&mut auto_start_cb)
+                    let reg = Arc::clone(&self.registry);
+                    Some(Box::new(move |rid: &DeviceId| {
+                        let renderer = reg.read().unwrap().get_renderer(rid).ok_or_else(|| 
+                            ControlPointError::ControlPoint(format!("Renderer {} not found", rid.0))
+                        )?;
+                        renderer.play_current_from_queue()
+                    }))
                } else {
                    None
                };
-            return refresh_attached_queue_for(
+            let _ = schedule_queue_refresh_for(
                &self.registry,
                renderer_id,
                &self.event_bus,
                callback,
            );
+            return Ok(());
        }

        // CRITICAL: When attaching a new playlist to a renderer, we must UNCONDITIONALLY
@@ -1247,21 +1240,25 @@ impl ControlPoint {
        // Note: BindingChanged event is emitted automatically by MusicRenderer::set_playlist_binding()

        // For initial attach with auto_play, force playback start (don't check if idle)
-        let mut auto_start_cb = |rid: &DeviceId| {
-            debug!(
-                renderer = rid.0.as_str(),
-                "Attach callback: forcing playback start (not checking if idle)"
-            );
-            self.play_current_from_queue(rid)
-        };
-        let callback: Option<&mut dyn FnMut(&DeviceId) -> Result<(), ControlPointError>> =
+        let callback: Option<Box<dyn FnOnce(&DeviceId) -> Result<(), ControlPointError> + Send + 'static>> =
            if auto_play {
-                Some(&mut auto_start_cb)
+                let reg = Arc::clone(&self.registry);
+                Some(Box::new(move |rid: &DeviceId| {
+                    debug!(
+                        renderer = rid.0.as_str(),
+                        "Attach callback: forcing playback start (not checking if idle)"
+                    );
+                    let renderer = reg.read().unwrap().get_renderer(rid).ok_or_else(|| 
+                        ControlPointError::ControlPoint(format!("Renderer {} not found", rid.0))
+                    )?;
+                    renderer.play_current_from_queue()
+                }))
            } else {
                None
            };

-        refresh_attached_queue_for(&self.registry, renderer_id, &self.event_bus, callback)
+        let _ = schedule_queue_refresh_for(&self.registry, renderer_id, &self.event_bus, callback);
+        Ok(())
    }

    /// Detach a renderer's queue from its associated playlist container.
@@ -1760,6 +1757,199 @@ fn refresh_attached_queue_for(
    Ok(())
 }

+fn fetch_queue_items_for(
+    music_server: &Arc<crate::media_server::MusicServer>,
+    container_id: &str,
+) -> Result<Vec<PlaybackItem>, ControlPointError> {
+    const MAX_BROWSE_ATTEMPTS: usize = 3;
+    const BROWSE_RETRY_DELAY_MS: u64 = 200;
+    const BROWSE_PAGE_SIZE: u32 = 64;
+
+    let entries = {
+        let mut all_entries = Vec::new();
+        let mut offset = 0u32;
+        loop {
+            let mut attempt = 1;
+            let page = loop {
+                match music_server.browse_children(container_id, offset, BROWSE_PAGE_SIZE) {
+                    Ok(e) => break e,
+                    Err(err) => {
+                        if attempt >= MAX_BROWSE_ATTEMPTS {
+                            return Err(err);
+                        }
+                        thread::sleep(Duration::from_millis(
+                            BROWSE_RETRY_DELAY_MS * attempt as u64,
+                        ));
+                        attempt += 1;
+                    }
+                }
+            };
+            let fetched = page.len() as u32;
+            all_entries.extend(page);
+            if fetched < BROWSE_PAGE_SIZE {
+                break;
+            }
+            offset += fetched;
+        }
+        all_entries
+    };
+
+    let new_items: Vec<PlaybackItem> = entries
+        .iter()
+        .filter_map(|entry| playback_item_from_entry(music_server.clone(), entry))
+        .collect();
+
+    Ok(new_items)
+}
+
+fn schedule_queue_refresh_for(
+    registry: &Arc<RwLock<DeviceRegistry>>,
+    renderer_id: &DeviceId,
+    event_bus: &RendererEventBus,
+    after_refresh: Option<Box<dyn FnOnce(&DeviceId) -> Result<(), ControlPointError> + Send + 'static>>,
+) -> SyncScheduleOutcome {
+    // Step 1: Get renderer from registry
+    let renderer = {
+        let reg = registry.read().unwrap();
+        reg.get_renderer(renderer_id)
+    };
+
+    let renderer = match renderer {
+        Some(r) => r,
+        None => {
+            debug!(
+                renderer = renderer_id.0.as_str(),
+                "schedule_queue_refresh_for: renderer not found"
+            );
+            return SyncScheduleOutcome::Scheduled;
+        }
+    };
+
+    // Check if there's a binding
+    let (server_id, container_id) = {
+        let binding = match renderer.get_playlist_binding() {
+            Some(b) => b,
+            None => {
+                debug!(
+                    renderer = renderer_id.0.as_str(),
+                    "schedule_queue_refresh_for: no binding present"
+                );
+                return SyncScheduleOutcome::Scheduled;
+            }
+        };
+        (binding.server_id.clone(), binding.container_id.clone())
+    };
+
+    // Step 2: Get server from registry
+    let music_server = {
+        let reg = registry.read().unwrap();
+        reg.get_server(&server_id)
+    };
+
+    let music_server = match music_server {
+        Some(s) => s,
+        None => {
+            warn!(
+                renderer = renderer_id.0.as_str(),
+                server = server_id.0.as_str(),
+                "schedule_queue_refresh_for: server not found in registry"
+            );
+            return SyncScheduleOutcome::Scheduled;
+        }
+    };
+
+    if !music_server.is_online() {
+        debug!(
+            renderer = renderer_id.0.as_str(),
+            server = server_id.0.as_str(),
+            "schedule_queue_refresh_for: server offline, skipping refresh"
+        );
+        return SyncScheduleOutcome::Scheduled;
+    }
+
+    // Emit QueueRefreshing
+    event_bus.broadcast(RendererEvent::QueueRefreshing {
+        id: renderer_id.clone(),
+    });
+
+    // Get the queue Arc
+    let queue_arc = {
+        let reg = registry.read().unwrap();
+        match reg.get_renderer_queue_arc(renderer_id) {
+            Some(q) => q,
+            None => {
+                warn!("schedule_queue_refresh_for: could not get queue arc");
+                return SyncScheduleOutcome::Scheduled;
+            }
+        }
+    };
+
+    // Build the pending_items_fn for re-fetching
+    let registry_clone = Arc::clone(registry);
+    let server_id_clone = server_id.clone();
+    let container_id_clone = container_id.clone();
+    let pending_fn = Box::new(move || {
+        let music_server = {
+            let reg = registry_clone.read().unwrap();
+            reg.get_server(&server_id_clone)
+        };
+        match music_server {
+            Some(s) => fetch_queue_items_for(&s, &container_id_clone),
+            None => Err(ControlPointError::MediaServerError("Server not found".to_string())),
+        }
+    });
+
+    // Build on_ready callback
+    let rid = renderer_id.clone();
+    let bus = event_bus.clone();
+    let after_cb = after_refresh;
+    let on_ready: Option<Box<dyn FnOnce() + Send + 'static>> = Some(Box::new(move || {
+        bus.broadcast(RendererEvent::QueueReadyToPlay { id: rid.clone() });
+        if let Some(cb) = after_cb {
+            if let Err(e) = cb(&rid) {
+                warn!("auto-play callback failed: {}", e);
+            }
+        }
+    }));
+
+    // Build on_complete callback
+    let rid2 = renderer_id.clone();
+    let bus2 = event_bus.clone();
+    let on_complete = Box::new(move |queue_len: usize| {
+        bus2.broadcast(RendererEvent::QueueUpdated {
+            id: rid2.clone(),
+            queue_length: queue_len,
+        });
+    });
+
+    // First fetch
+    let items = match fetch_queue_items_for(&music_server, &container_id) {
+        Ok(items) => items,
+        Err(e) => {
+            warn!("schedule_queue_refresh_for: failed to fetch items: {}", e);
+            return SyncScheduleOutcome::Scheduled;
+        }
+    };
+
+    // Call schedule_sync
+    let outcome = crate::queue::MusicQueue::schedule_sync(
+        &queue_arc,
+        &renderer_id.0,
+        items,
+        pending_fn,
+        on_ready,
+        on_complete,
+    );
+
+    if matches!(outcome, SyncScheduleOutcome::AlreadyRunning) {
+        event_bus.broadcast(RendererEvent::QueueSyncCancelled {
+            id: renderer_id.clone(),
+        });
+    }
+
+    outcome
+}
+
 fn didl_item_from_playback_item(item: &PlaybackItem) -> DidlItem {
    let metadata = item.metadata.as_ref();
    let title = metadata
--- a/pmocontrol/src/errors.rs
+++ b/pmocontrol/src/errors.rs
@@ -49,6 +49,8 @@ pub enum ControlPointError {
    SnapshotError(String),
    #[error("Error on ControlPoint: {0}")]
    ControlPoint(String),
+    #[error("Queue sync cancelled (superseded by a newer request)")]
+    SyncCancelled,
 }

 impl ControlPointError {
--- a/pmocontrol/src/model.rs
+++ b/pmocontrol/src/model.rs
@@ -437,6 +437,12 @@ pub enum RendererEvent {
    QueueRefreshing {
        id: DeviceId,
    },
+    QueueReadyToPlay {
+        id: DeviceId,
+    },
+    QueueSyncCancelled {
+        id: DeviceId,
+    },
    BindingChanged {
        id: DeviceId,
        binding: Option<PlaylistBinding>,
--- a/pmocontrol/src/music_renderer/arylic_tcp.rs
+++ b/pmocontrol/src/music_renderer/arylic_tcp.rs
@@ -1,26 +1,26 @@
-use std::sync::{Arc, Mutex};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};
 use std::time::Duration;

 use serde::Deserialize;
 use tracing::debug;

-use crate::DeviceIdentity;
 use crate::arylic_client::{
-    ARYLIC_TCP_PORT, DEFAULT_TIMEOUT_SECS, send_command_no_response, send_command_optional,
-    send_command_required,
+    send_command_no_response, send_command_optional, send_command_required, ARYLIC_TCP_PORT,
+    DEFAULT_TIMEOUT_SECS,
 };
 use crate::errors::ControlPointError;
 use crate::linkplay_client::extract_linkplay_host;
 use crate::model::{PlaybackState, RendererInfo};
-use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::music_renderer::capabilities::{
    PlaybackPosition, PlaybackPositionInfo, PlaybackStatus, QueueTransportControl, RendererBackend,
    TransportControl, VolumeControl,
 };
 use crate::music_renderer::musicrenderer::MusicRendererBackend;
 use crate::music_renderer::time_utils::{format_hhmmss, ms_to_seconds, parse_hhmmss_strict};
+use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::queue::MusicQueue;
 use crate::queue::{EnqueueMode, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::DeviceIdentity;

 /// Raw response from Arylic MCU+PINFGET command
 #[derive(Debug, Deserialize)]
@@ -409,8 +409,16 @@ impl QueueBackend for ArylicTcpRenderer {
            .replace_queue(items, current_index)
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().sync_queue(items)
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        _cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        self.queue
+            .lock()
+            .unwrap()
+            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
--- a/pmocontrol/src/music_renderer/chromecast_renderer.rs
+++ b/pmocontrol/src/music_renderer/chromecast_renderer.rs
@@ -11,6 +11,7 @@
 //! are wrapped in sync calls using smol::block_on for compatibility with
 //! the existing sync trait interfaces.

+use std::sync::atomic::AtomicBool;
 use std::sync::{Arc, Mutex, Once};
 use std::thread::JoinHandle;

@@ -906,8 +907,16 @@ impl QueueBackend for ChromecastRenderer {
            .replace_queue(items, current_index)
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().sync_queue(items)
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        _cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        self.queue
+            .lock()
+            .unwrap()
+            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
--- a/pmocontrol/src/music_renderer/linkplay_renderer.rs
+++ b/pmocontrol/src/music_renderer/linkplay_renderer.rs
@@ -1,24 +1,24 @@
 use std::fmt;
-use std::sync::{Arc, Mutex};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};
 use std::time::Duration;

 use ureq::Agent;

-use crate::DeviceIdentity;
 use crate::errors::ControlPointError;
 use crate::linkplay_client::{
-    LinkPlayStatus, build_agent, extract_linkplay_host, fetch_status_for_host, percent_encode,
+    build_agent, extract_linkplay_host, fetch_status_for_host, percent_encode, LinkPlayStatus,
 };
 use crate::model::{PlaybackState, RendererInfo};
-use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::music_renderer::capabilities::{
    PlaybackPosition, PlaybackPositionInfo, PlaybackStatus, QueueTransportControl, RendererBackend,
    TransportControl, VolumeControl,
 };
 use crate::music_renderer::musicrenderer::MusicRendererBackend;
 use crate::music_renderer::time_utils::parse_hhmmss_strict;
+use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::queue::MusicQueue;
 use crate::queue::{EnqueueMode, PlaybackItem, QueueBackend, QueueSnapshot};
+use crate::DeviceIdentity;

 const DEFAULT_HTTP_TIMEOUT_SECS: u64 = 3;

@@ -287,8 +287,16 @@ impl QueueBackend for LinkPlayRenderer {
            .replace_queue(items, current_index)
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().sync_queue(items)
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        _cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        self.queue
+            .lock()
+            .unwrap()
+            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
--- a/pmocontrol/src/music_renderer/musicrenderer.rs
+++ b/pmocontrol/src/music_renderer/musicrenderer.rs
@@ -976,6 +976,12 @@ impl MusicRenderer {
        Ok(snapshot)
    }

+    /// Get a clone of the queue Arc (for async sync operations).
+    pub fn queue(&self) -> Arc<Mutex<MusicQueue>> {
+        let backend = self.lock_backend_for("queue");
+        crate::music_renderer::capabilities::RendererBackend::queue(&*backend).clone()
+    }
+
    /// Get the current queue item without advancing.
    /// Returns the item and count of remaining items after current.
    pub fn peek_current(&self) -> Result<Option<(PlaybackItem, usize)>, ControlPointError> {
@@ -1372,7 +1378,16 @@ impl MusicRenderer {
    /// - If the current track is NOT in the new items, it's preserved as the first item
    /// - If there's no current track, the queue is simply replaced
    pub fn sync_queue(&self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        // Mark renderer as active for adaptive polling
+        self.sync_queue_with_callback(items, None, None)
+    }
+
+    /// Synchronize the queue with new items with optional cancel token and on_ready callback.
+    pub fn sync_queue_with_callback(
+        &self,
+        items: Vec<PlaybackItem>,
+        cancel_token: Option<&Arc<AtomicBool>>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
        {
            let mut watched = self
                .watched_state
@@ -1382,7 +1397,9 @@ impl MusicRenderer {
        }

        let mut backend = self.lock_backend_for("sync_queue");
-        backend.sync_queue(items)?;
+        let dummy_token = Arc::new(AtomicBool::new(false));
+        let token = cancel_token.unwrap_or(&dummy_token);
+        backend.sync_queue(items, token, on_ready)?;
        drop(backend);
        self.emit_queue_updated();
        Ok(())
@@ -2283,14 +2300,21 @@ impl QueueBackend for MusicRendererBackend {
        }
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
        match self {
-            MusicRendererBackend::Upnp(r) => r.sync_queue(items),
-            MusicRendererBackend::OpenHome(r) => r.sync_queue(items),
-            MusicRendererBackend::LinkPlay(r) => r.sync_queue(items),
-            MusicRendererBackend::ArylicTcp(r) => r.sync_queue(items),
-            MusicRendererBackend::Chromecast(cc) => cc.sync_queue(items),
-            MusicRendererBackend::HybridUpnpArylic { upnp, .. } => upnp.sync_queue(items),
+            MusicRendererBackend::Upnp(r) => r.sync_queue(items, cancel_token, on_ready),
+            MusicRendererBackend::OpenHome(r) => r.sync_queue(items, cancel_token, on_ready),
+            MusicRendererBackend::LinkPlay(r) => r.sync_queue(items, cancel_token, on_ready),
+            MusicRendererBackend::ArylicTcp(r) => r.sync_queue(items, cancel_token, on_ready),
+            MusicRendererBackend::Chromecast(cc) => cc.sync_queue(items, cancel_token, on_ready),
+            MusicRendererBackend::HybridUpnpArylic { upnp, .. } => {
+                upnp.sync_queue(items, cancel_token, on_ready)
+            }
        }
    }

--- a/pmocontrol/src/music_renderer/openhome_renderer.rs
+++ b/pmocontrol/src/music_renderer/openhome_renderer.rs
@@ -1,4 +1,4 @@
-use std::sync::{Arc, Mutex};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};
 use std::time::SystemTime;

 use crate::music_renderer::capabilities::{
@@ -182,9 +182,8 @@ impl OpenHomeRenderer {
    /// Retourne les IDs des pistes de la playlist OpenHome.
    /// Plus rapide que snapshot_openhome_playlist() car ne récupère pas les métadonnées.
    pub(crate) fn openhome_playlist_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        // Use the queue's cached track_ids() instead of direct id_array() call
        let queue = self.queue.lock().unwrap();
-        if let MusicQueue::OpenHome(oh_queue) = &*queue {
+        if let Some(oh_queue) = queue.as_openhome() {
            oh_queue.track_ids()
        } else {
            Err(ControlPointError::QueueError(
@@ -209,9 +208,8 @@ impl OpenHomeRenderer {
        let insert_after = match after_id {
            Some(id) => id,
            None => {
-                // Use the queue's cached track_ids() instead of direct id_array() call
                let queue = self.queue.lock().unwrap();
-                if let MusicQueue::OpenHome(oh_queue) = &*queue {
+                if let Some(oh_queue) = queue.as_openhome() {
                    oh_queue
                        .track_ids()?
                        .last()
@@ -413,7 +411,7 @@ impl PlaybackPosition for OpenHomeRenderer {

        // Get track ID from queue (uses cached data)
        let queue_guard_for_id = self.queue.lock().unwrap();
-        if let MusicQueue::OpenHome(oh_queue) = &*queue_guard_for_id {
+        if let Some(oh_queue) = queue_guard_for_id.as_openhome() {
            match oh_queue.current_track() {
                Ok(id_opt) => track_id = id_opt,
                Err(err) => debug!(
@@ -696,11 +694,16 @@ impl QueueBackend for OpenHomeRenderer {
            .replace_queue(items, current_index)
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
        self.queue
            .lock()
            .map_err(|_| ControlPointError::QueueError("Queue mutex poisoned".into()))?
-            .sync_queue(items)
+            .sync_queue(items, cancel_token, on_ready)
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
--- a/pmocontrol/src/music_renderer/upnp_renderer.rs
+++ b/pmocontrol/src/music_renderer/upnp_renderer.rs
@@ -1,13 +1,13 @@
-use std::sync::{Arc, Mutex};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};

 use crate::errors::ControlPointError;
 use crate::model::PlaybackState;
-use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::music_renderer::capabilities::{
    PlaybackPosition, PlaybackPositionInfo, PlaybackStatus, QueueTransportControl, RendererBackend,
    TransportControl, VolumeControl,
 };
-use crate::music_renderer::musicrenderer::{MusicRendererBackend, build_didl_lite_metadata};
+use crate::music_renderer::musicrenderer::{build_didl_lite_metadata, MusicRendererBackend};
+use crate::music_renderer::RendererFromMediaRendererInfo;
 use crate::queue::{EnqueueMode, MusicQueue, PlaybackItem, QueueBackend, QueueSnapshot};
 use crate::upnp_clients::{
    AvTransportClient, ConnectionInfo, ConnectionManagerClient, PositionInfo, ProtocolInfo,
@@ -318,8 +318,16 @@ impl QueueBackend for UpnpRenderer {
            .replace_queue(items, current_index)
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        self.queue.lock().unwrap().sync_queue(items)
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        _cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        self.queue
+            .lock()
+            .unwrap()
+            .sync_queue(items, &Arc::new(AtomicBool::new(false)), on_ready)
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
--- a/pmocontrol/src/queue/backend.rs
+++ b/pmocontrol/src/queue/backend.rs
@@ -28,7 +28,8 @@
 //!   - This identity is used by the sync helpers to preserve the current
 //!     track across queue rebuilds when the MediaServer content changes.

-use crate::{PlaybackItem, QueueSnapshot, errors::ControlPointError};
+use crate::{errors::ControlPointError, PlaybackItem, QueueSnapshot};
+use std::sync::{atomic::AtomicBool, Arc};

 /// High-level enqueue mode.
 ///
@@ -107,7 +108,12 @@ pub trait QueueBackend {
    /// corresponds to the old current index track.
    /// If the old current index track is absent from the new queue,
    /// it is kept as the first item and the new items are appended after it.
-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError>;
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError>;

    /// Returns the item at `index`, if it exists.
    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError>;
--- a/pmocontrol/src/queue/interne.rs
+++ b/pmocontrol/src/queue/interne.rs
@@ -20,6 +20,7 @@ use crate::{
    queue::{MusicQueue, PlaybackItem, QueueBackend, QueueFromRendererInfo, QueueSnapshot},
    DeviceId, DeviceIdentity, RendererInfo,
 };
+use std::sync::{atomic::AtomicBool, Arc};

 /// Internal/local queue implementation.
 ///
@@ -269,25 +270,43 @@ impl QueueBackend for InternalQueue {
        Ok(())
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        use tracing::debug;
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        mut on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        use std::sync::atomic::Ordering::SeqCst;

-        if items.is_empty() {
-            return self.replace_queue(Vec::new(), None);
+        if cancel_token.load(SeqCst) {
+            return Err(ControlPointError::SyncCancelled);
+        }
+
+        let has_current = self.current_index().ok().flatten().is_some();
+        if has_current {
+            if let Some(f) = on_ready.take() {
+                f();
+            }
+        }
+
+        if items.is_empty() {
+            let _ = self.replace_queue(Vec::new(), None);
+            return Ok(());
        }

-        // Protéger les durées des streams contre la diminution
        let updated_items = self.protect_stream_durations(items);

-        // Récupérer l'item actuel
        let current = self.current_index.and_then(|idx| {
            self.items
                .get(idx)
                .map(|item| (idx, item.uri.clone(), item.didl_id.clone()))
        });

+        if cancel_token.load(SeqCst) {
+            return Err(ControlPointError::SyncCancelled);
+        }
+
        if let Some((_current_idx, current_uri, current_didl_id)) = current {
-            // Chercher l'item actuel dans la nouvelle liste (par URI d'abord, puis par didl_id)
            let new_idx = updated_items
                .iter()
                .position(|item| item.uri == current_uri)
@@ -298,34 +317,25 @@ impl QueueBackend for InternalQueue {
                });

            if let Some(new_idx) = new_idx {
-                // Item trouvé dans la nouvelle liste
-                debug!(
-                    renderer = self.renderer_id.0.as_str(),
-                    current_uri = current_uri.as_str(),
-                    new_idx,
-                    "sync_queue: current item found in new playlist"
-                );
-                self.replace_queue(updated_items, Some(new_idx))
+                self.replace_queue(updated_items, Some(new_idx))?;
            } else {
-                // Item pas trouvé - cela ne devrait pas arriver si la playlist n'a pas changé
-                // Loguer pour diagnostic
-                debug!(
-                    renderer = self.renderer_id.0.as_str(),
-                    current_uri = current_uri.as_str(),
-                    current_didl_id = current_didl_id.as_str(),
-                    new_items_count = updated_items.len(),
-                    "sync_queue: current item NOT found in new playlist, preserving as first item"
-                );
                let current_item = self.items[self.current_index.unwrap()].clone();
                let mut new_items = Vec::with_capacity(updated_items.len() + 1);
                new_items.push(current_item);
                new_items.extend(updated_items);
-                self.replace_queue(new_items, Some(0))
+                self.replace_queue(new_items, Some(0))?;
            }
        } else {
-            // Pas d'item actuel
-            self.replace_queue(updated_items, None)
+            self.replace_queue(updated_items, None)?;
        }
+
+        if !has_current {
+            if let Some(f) = on_ready.take() {
+                f();
+            }
+        }
+
+        Ok(())
    }

    fn enqueue_items(
@@ -502,6 +512,6 @@ impl QueueFromRendererInfo for InternalQueue {
    }

    fn to_backend(self) -> MusicQueue {
-        MusicQueue::Internal(self)
+        MusicQueue::from_internal(self)
    }
 }
--- a/pmocontrol/src/queue/mod.rs
+++ b/pmocontrol/src/queue/mod.rs
@@ -7,20 +7,23 @@ mod snapshot;
 use std::sync::{Arc, Mutex};

 pub use backend::{EnqueueMode, QueueBackend};
-pub use music_queue::MusicQueue;
+pub use music_queue::{MusicQueue, SyncScheduleOutcome};
 pub use snapshot::{PlaybackItem, QueueSnapshot};

 // Internal queue implementations - not part of the public API
 pub(crate) use interne::InternalQueue;
 pub(crate) use openhome::OpenHomeQueue;

-use crate::{RendererInfo, errors::ControlPointError};
 use crate::music_renderer::time_utils::parse_time_flexible;
+use crate::{errors::ControlPointError, RendererInfo};

 /// Returns true if `new_dur` < `old_dur` (both parseable as HH:MM:SS/MM:SS/SS).
 /// Used to protect stream durations from decreasing for the same track.
 pub(super) fn stream_duration_decreased(old_dur: &str, new_dur: &str) -> bool {
-    match (parse_time_flexible(old_dur).ok(), parse_time_flexible(new_dur).ok()) {
+    match (
+        parse_time_flexible(old_dur).ok(),
+        parse_time_flexible(new_dur).ok(),
+    ) {
        (Some(old_secs), Some(new_secs)) => new_secs < old_secs,
        _ => false,
    }
@@ -28,7 +31,10 @@ pub(super) fn stream_duration_decreased(old_dur: &str, new_dur: &str) -> bool {

 /// Returns true if `new_dur` > `old_dur` (both parseable as HH:MM:SS/MM:SS/SS).
 pub(super) fn stream_duration_increased(old_dur: &str, new_dur: &str) -> bool {
-    match (parse_time_flexible(old_dur).ok(), parse_time_flexible(new_dur).ok()) {
+    match (
+        parse_time_flexible(old_dur).ok(),
+        parse_time_flexible(new_dur).ok(),
+    ) {
        (Some(old_secs), Some(new_secs)) => new_secs > old_secs,
        _ => false,
    }
--- a/pmocontrol/src/queue/music_queue.rs
+++ b/pmocontrol/src/queue/music_queue.rs
@@ -3,84 +3,297 @@ use crate::queue::{
    EnqueueMode, InternalQueue, OpenHomeQueue, QueueBackend, QueueFromRendererInfo,
 };
 use crate::{PlaybackItem, QueueSnapshot, RendererInfo};
+use std::sync::{
+    atomic::{AtomicBool, Ordering::SeqCst},
+    Arc, Mutex,
+};
+use std::thread;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SyncScheduleOutcome {
+    Scheduled,
+    AlreadyRunning,
+}

 #[derive(Debug)]
-pub enum MusicQueue {
+enum MusicQueueBackend {
    Internal(InternalQueue),
    OpenHome(OpenHomeQueue),
 }

+#[derive(Debug)]
+pub struct MusicQueue {
+    backend: MusicQueueBackend,
+    sync_in_progress: Arc<AtomicBool>,
+    sync_pending: Arc<AtomicBool>,
+    sync_cancel_token: Arc<AtomicBool>,
+}
+
 impl MusicQueue {
    /// Creates a queue appropriate for the given renderer.
    /// This is the factory method used by QueueFromRendererInfo trait.
    pub fn from_renderer_info(info: &RendererInfo) -> Result<MusicQueue, ControlPointError> {
-        if info.capabilities().has_oh_playlist() {
-            Ok(MusicQueue::OpenHome(OpenHomeQueue::from_renderer_info(
-                info,
-            )?))
+        let backend = if info.capabilities().has_oh_playlist() {
+            MusicQueueBackend::OpenHome(OpenHomeQueue::from_renderer_info(info)?)
        } else {
-            Ok(MusicQueue::Internal(InternalQueue::from_renderer_info(
-                info,
-            )?))
+            MusicQueueBackend::Internal(InternalQueue::from_renderer_info(info)?)
+        };
+
+        Ok(MusicQueue {
+            backend,
+            sync_in_progress: Arc::new(AtomicBool::new(false)),
+            sync_pending: Arc::new(AtomicBool::new(false)),
+            sync_cancel_token: Arc::new(AtomicBool::new(false)),
+        })
+    }
+
+    /// Creates a MusicQueue from an InternalQueue backend.
+    pub fn from_internal(queue: InternalQueue) -> MusicQueue {
+        MusicQueue {
+            backend: MusicQueueBackend::Internal(queue),
+            sync_in_progress: Arc::new(AtomicBool::new(false)),
+            sync_pending: Arc::new(AtomicBool::new(false)),
+            sync_cancel_token: Arc::new(AtomicBool::new(false)),
        }
    }
+
+    /// Creates a MusicQueue from an OpenHomeQueue backend.
+    pub fn from_openhome(queue: OpenHomeQueue) -> MusicQueue {
+        MusicQueue {
+            backend: MusicQueueBackend::OpenHome(queue),
+            sync_in_progress: Arc::new(AtomicBool::new(false)),
+            sync_pending: Arc::new(AtomicBool::new(false)),
+            sync_cancel_token: Arc::new(AtomicBool::new(false)),
+        }
+    }
+
+    /// Returns true if this is an OpenHome backend.
+    pub fn is_openhome(&self) -> bool {
+        matches!(self.backend, MusicQueueBackend::OpenHome(_))
+    }
+
+    /// Returns a reference to the OpenHome queue if this is an OpenHome backend.
+    pub fn as_openhome(&self) -> Option<&OpenHomeQueue> {
+        match &self.backend {
+            MusicQueueBackend::OpenHome(q) => Some(q),
+            MusicQueueBackend::Internal(_) => None,
+        }
+    }
+
+    /// Returns a mutable reference to the OpenHome queue if this is an OpenHome backend.
+    pub fn as_openhome_mut(&mut self) -> Option<&mut OpenHomeQueue> {
+        match &mut self.backend {
+            MusicQueueBackend::OpenHome(q) => Some(q),
+            MusicQueueBackend::Internal(_) => None,
+        }
+    }
+
+    pub fn len(&self) -> Result<usize, ControlPointError> {
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.len(),
+            MusicQueueBackend::OpenHome(q) => q.len(),
+        }
+    }
+
+    pub fn schedule_sync(
+        queue_arc: &Arc<Mutex<MusicQueue>>,
+        renderer_id: &str,
+        items: Vec<PlaybackItem>,
+        pending_items_fn: Box<
+            dyn Fn() -> Result<Vec<PlaybackItem>, ControlPointError> + Send + 'static,
+        >,
+        on_ready: Option<Box<dyn FnOnce() + Send + 'static>>,
+        on_complete: Box<dyn Fn(usize) + Send + 'static>,
+    ) -> SyncScheduleOutcome {
+        let (sync_in_progress, sync_pending, sync_cancel_token) = {
+            let q = queue_arc.lock().unwrap();
+            (
+                Arc::clone(&q.sync_in_progress),
+                Arc::clone(&q.sync_pending),
+                Arc::clone(&q.sync_cancel_token),
+            )
+        };
+
+        if sync_in_progress.swap(true, SeqCst) {
+            sync_cancel_token.store(true, SeqCst);
+            sync_pending.store(true, SeqCst);
+            return SyncScheduleOutcome::AlreadyRunning;
+        }
+
+        sync_cancel_token.store(false, SeqCst);
+        sync_pending.store(false, SeqCst);
+
+        let queue_arc = Arc::clone(queue_arc);
+        let thread_name = format!("queue-sync-{}", renderer_id);
+
+        thread::Builder::new()
+            .name(thread_name)
+            .spawn(move || {
+                struct Guard(Arc<AtomicBool>);
+                impl Drop for Guard {
+                    fn drop(&mut self) {
+                        self.0.store(false, SeqCst);
+                    }
+                }
+                let _guard = Guard(Arc::clone(&sync_in_progress));
+
+                let mut current_items = items;
+                let mut current_on_ready = Some(on_ready);
+                let mut on_complete = Some(on_complete);
+
+                tracing::debug!(thread = %std::thread::current().name().unwrap_or("?"), "queue-sync thread started");
+
+                loop {
+                    sync_pending.store(false, SeqCst);
+                    sync_cancel_token.store(false, SeqCst);
+
+                    // Extract the real on_ready BEFORE locking the queue.
+                    // on_ready may call play_from_queue() which re-locks the queue,
+                    // so we must NOT call it while holding queue_arc.
+                    let real_on_ready = current_on_ready.take().flatten();
+                    let on_ready_triggered = Arc::new(AtomicBool::new(false));
+                    let proxy_on_ready: Option<Box<dyn FnOnce() + Send + 'static>> =
+                        real_on_ready.as_ref().map(|_| {
+                            let flag = Arc::clone(&on_ready_triggered);
+                            Box::new(move || {
+                                flag.store(true, SeqCst);
+                            }) as Box<dyn FnOnce() + Send + 'static>
+                        });
+
+                    tracing::debug!(
+                        thread = %std::thread::current().name().unwrap_or("?"),
+                        items = current_items.len(),
+                        has_on_ready = real_on_ready.is_some(),
+                        "queue-sync: calling sync_queue"
+                    );
+
+                    let result = {
+                        let mut q = queue_arc.lock().unwrap();
+                        <MusicQueue as QueueBackend>::sync_queue(
+                            &mut q,
+                            current_items,
+                            &sync_cancel_token,
+                            proxy_on_ready,
+                        )
+                    };
+                    // Queue lock is released here.
+                    // Now safe to call on_ready (which may re-lock the queue).
+                    if on_ready_triggered.load(SeqCst) {
+                        tracing::debug!(
+                            thread = %std::thread::current().name().unwrap_or("?"),
+                            "queue-sync: on_ready triggered, calling callback"
+                        );
+                        if let Some(f) = real_on_ready {
+                            f();
+                        }
+                    } else if real_on_ready.is_some() {
+                        tracing::debug!(
+                            thread = %std::thread::current().name().unwrap_or("?"),
+                            "queue-sync: on_ready not triggered (cancelled or skipped)"
+                        );
+                    }
+
+                    match result {
+                        Err(ControlPointError::SyncCancelled) => {
+                            tracing::debug!(
+                                thread = %std::thread::current().name().unwrap_or("?"),
+                                "queue-sync: cancelled"
+                            );
+                        }
+                        Err(e) => {
+                            tracing::warn!("queue-sync error: {}", e);
+                        }
+                        Ok(()) => {
+                            tracing::debug!(
+                                thread = %std::thread::current().name().unwrap_or("?"),
+                                "queue-sync: completed successfully"
+                            );
+                            if let Some(cb) = on_complete.take() {
+                                let queue_len = queue_arc.lock().unwrap().len().unwrap_or(0);
+                                cb(queue_len);
+                            }
+                        }
+                    }
+
+                    if !sync_pending.load(SeqCst) {
+                        break;
+                    }
+
+                    match pending_items_fn() {
+                        Ok(new_items) => {
+                            current_items = new_items;
+                            current_on_ready = Some(None);
+                        }
+                        Err(e) => {
+                            tracing::warn!("queue-sync pending re-fetch error: {}", e);
+                            break;
+                        }
+                    }
+                }
+
+                tracing::debug!(thread = %std::thread::current().name().unwrap_or("?"), "queue-sync thread done");
+            })
+            .expect("Failed to spawn queue-sync thread");
+
+        SyncScheduleOutcome::Scheduled
+    }
 }

 impl QueueBackend for MusicQueue {
    // Primitives
    fn len(&self) -> Result<usize, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.len(),
-            MusicQueue::OpenHome(q) => q.len(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.len(),
+            MusicQueueBackend::OpenHome(q) => q.len(),
        }
    }

    fn track_ids(&self) -> Result<Vec<u32>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.track_ids(),
-            MusicQueue::OpenHome(q) => q.track_ids(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.track_ids(),
+            MusicQueueBackend::OpenHome(q) => q.track_ids(),
        }
    }

    fn id_to_position(&self, id: u32) -> Result<usize, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.id_to_position(id),
-            MusicQueue::OpenHome(q) => q.id_to_position(id),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.id_to_position(id),
+            MusicQueueBackend::OpenHome(q) => q.id_to_position(id),
        }
    }

    fn position_to_id(&self, id: usize) -> Result<u32, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.position_to_id(id),
-            MusicQueue::OpenHome(q) => q.position_to_id(id),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.position_to_id(id),
+            MusicQueueBackend::OpenHome(q) => q.position_to_id(id),
        }
    }

    fn current_track(&self) -> Result<Option<u32>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.current_track(),
-            MusicQueue::OpenHome(q) => q.current_track(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.current_track(),
+            MusicQueueBackend::OpenHome(q) => q.current_track(),
        }
    }

    fn current_index(&self) -> Result<Option<usize>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.current_index(),
-            MusicQueue::OpenHome(q) => q.current_index(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.current_index(),
+            MusicQueueBackend::OpenHome(q) => q.current_index(),
        }
    }

    fn queue_snapshot(&self) -> Result<QueueSnapshot, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.queue_snapshot(),
-            MusicQueue::OpenHome(q) => q.queue_snapshot(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.queue_snapshot(),
+            MusicQueueBackend::OpenHome(q) => q.queue_snapshot(),
        }
    }

    fn set_index(&mut self, index: Option<usize>) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.set_index(index),
-            MusicQueue::OpenHome(q) => q.set_index(index),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.set_index(index),
+            MusicQueueBackend::OpenHome(q) => q.set_index(index),
        }
    }

@@ -89,30 +302,35 @@ impl QueueBackend for MusicQueue {
        items: Vec<PlaybackItem>,
        current_index: Option<usize>,
    ) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.replace_queue(items, current_index),
-            MusicQueue::OpenHome(q) => q.replace_queue(items, current_index),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.replace_queue(items, current_index),
+            MusicQueueBackend::OpenHome(q) => q.replace_queue(items, current_index),
        }
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.sync_queue(items),
-            MusicQueue::OpenHome(q) => q.sync_queue(items),
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.sync_queue(items, cancel_token, on_ready),
+            MusicQueueBackend::OpenHome(q) => q.sync_queue(items, cancel_token, on_ready),
        }
    }

    fn get_item(&self, index: usize) -> Result<Option<PlaybackItem>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.get_item(index),
-            MusicQueue::OpenHome(q) => q.get_item(index),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.get_item(index),
+            MusicQueueBackend::OpenHome(q) => q.get_item(index),
        }
    }

    fn replace_item(&mut self, index: usize, item: PlaybackItem) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.replace_item(index, item),
-            MusicQueue::OpenHome(q) => q.replace_item(index, item),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.replace_item(index, item),
+            MusicQueueBackend::OpenHome(q) => q.replace_item(index, item),
        }
    }

@@ -121,59 +339,59 @@ impl QueueBackend for MusicQueue {
        items: Vec<PlaybackItem>,
        mode: EnqueueMode,
    ) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.enqueue_items(items, mode),
-            MusicQueue::OpenHome(q) => q.enqueue_items(items, mode),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.enqueue_items(items, mode),
+            MusicQueueBackend::OpenHome(q) => q.enqueue_items(items, mode),
        }
    }

    // Optimized helpers
    fn clear_queue(&mut self) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.clear_queue(),
-            MusicQueue::OpenHome(q) => q.clear_queue(),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.clear_queue(),
+            MusicQueueBackend::OpenHome(q) => q.clear_queue(),
        }
    }

    fn is_empty(&self) -> Result<bool, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.is_empty(),
-            MusicQueue::OpenHome(q) => q.is_empty(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.is_empty(),
+            MusicQueueBackend::OpenHome(q) => q.is_empty(),
        }
    }

    fn upcoming_len(&self) -> Result<usize, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.upcoming_len(),
-            MusicQueue::OpenHome(q) => q.upcoming_len(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.upcoming_len(),
+            MusicQueueBackend::OpenHome(q) => q.upcoming_len(),
        }
    }

    fn upcoming_items(&self) -> Result<Vec<PlaybackItem>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.upcoming_items(),
-            MusicQueue::OpenHome(q) => q.upcoming_items(),
+        match &self.backend {
+            MusicQueueBackend::Internal(q) => q.upcoming_items(),
+            MusicQueueBackend::OpenHome(q) => q.upcoming_items(),
        }
    }

    fn peek_current(&mut self) -> Result<Option<(PlaybackItem, usize)>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.peek_current(),
-            MusicQueue::OpenHome(q) => q.peek_current(),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.peek_current(),
+            MusicQueueBackend::OpenHome(q) => q.peek_current(),
        }
    }

    fn dequeue_next(&mut self) -> Result<Option<(PlaybackItem, usize)>, ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.dequeue_next(),
-            MusicQueue::OpenHome(q) => q.dequeue_next(),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.dequeue_next(),
+            MusicQueueBackend::OpenHome(q) => q.dequeue_next(),
        }
    }

    fn append_or_init_index(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
-        match self {
-            MusicQueue::Internal(q) => q.append_or_init_index(items),
-            MusicQueue::OpenHome(q) => q.append_or_init_index(items),
+        match &mut self.backend {
+            MusicQueueBackend::Internal(q) => q.append_or_init_index(items),
+            MusicQueueBackend::OpenHome(q) => q.append_or_init_index(items),
        }
    }
 }
--- a/pmocontrol/src/queue/openhome.rs
+++ b/pmocontrol/src/queue/openhome.rs
@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use std::sync::{Arc, Mutex};
+use std::sync::{atomic::AtomicBool, Arc, Mutex};
 use std::time::SystemTime;
 use std::usize;

@@ -170,6 +170,8 @@ pub struct OpenHomeQueue {
    /// Permet de maintenir des métadonnées à jour même si le service OpenHome
    /// ne permet pas de les modifier directement.
    metadata_cache: Mutex<HashMap<u32, Option<crate::model::TrackMetadata>>>,
+    /// Cache URI by track ID for fast path matching
+    uri_by_id: Mutex<HashMap<u32, String>>,
    /// Cache for track IDs to avoid redundant IdArray SOAP calls
    track_ids_cache: Arc<Mutex<TrackIdsCache>>,
    /// Cache for current track ID to avoid redundant Id SOAP calls
@@ -178,6 +180,16 @@ pub struct OpenHomeQueue {
    read_list_cache: Arc<Mutex<ReadListCache>>,
 }

+/// Fast path result for queue sync optimization
+enum FastPathResult {
+    /// New items are an append to the current queue
+    AppendOnly { new_items: Vec<PlaybackItem> },
+    /// Items were deleted from the end
+    DeleteFromEnd { delete_ids: Vec<u32> },
+    /// No fast path possible - need full LCS sync
+    NeedFullSync,
+}
+
 impl OpenHomeQueue {
    pub fn new(
        renderer_id: DeviceId,
@@ -191,6 +203,7 @@ impl OpenHomeQueue {
            info_client,
            product_client,
            metadata_cache: Mutex::new(HashMap::new()),
+            uri_by_id: Mutex::new(HashMap::new()),
            track_ids_cache: Arc::new(Mutex::new(TrackIdsCache::new())),
            current_track_id_cache: Arc::new(Mutex::new(CurrentTrackIdCache::new())),
            read_list_cache: Arc::new(Mutex::new(ReadListCache::new())),
@@ -229,6 +242,117 @@ impl OpenHomeQueue {
        self.track_ids_cache.lock().unwrap().invalidate();
        self.read_list_cache.lock().unwrap().invalidate();
        self.current_track_id_cache.lock().unwrap().invalidate();
+        self.uri_by_id.lock().unwrap().clear();
+    }
+
+    /// Tries to detect a simple append-only or delete-from-end pattern without ReadList.
+    ///
+    /// This is a fast path optimization that avoids the expensive ReadList calls when:
+    /// 1. New items are an append to existing queue (only inserts needed)
+    /// 2. Items were deleted from the end (only deletes needed)
+    ///
+    /// Returns `FastPathResult::NeedFullSync` if the pattern doesn't match or
+    /// if cache data is insufficient to verify.
+    fn try_fast_path(&self, new_items: &[PlaybackItem]) -> FastPathResult {
+        let current_ids = match self.track_ids() {
+            Ok(ids) => ids,
+            Err(e) => {
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    error = %e,
+                    "try_fast_path: failed to get current IDs, falling back to full sync"
+                );
+                return FastPathResult::NeedFullSync;
+            }
+        };
+
+        let current_len = current_ids.len();
+        let new_len = new_items.len();
+
+        if new_len > current_len {
+            let prefix_matches = self.check_prefix_matches(&current_ids, &new_items[..current_len]);
+            if prefix_matches {
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    current_len, new_len, "try_fast_path: detected append-only pattern"
+                );
+                return FastPathResult::AppendOnly {
+                    new_items: new_items[current_len..].to_vec(),
+                };
+            }
+        } else if new_len < current_len {
+            let prefix_matches = self.check_prefix_matches(&current_ids[..new_len], new_items);
+            if prefix_matches {
+                let delete_ids: Vec<u32> = current_ids[new_len..].to_vec();
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    current_len,
+                    new_len,
+                    delete_count = delete_ids.len(),
+                    "try_fast_path: detected delete-from-end pattern"
+                );
+                return FastPathResult::DeleteFromEnd { delete_ids };
+            }
+        }
+
+        debug!(
+            renderer = self.renderer_id.0.as_str(),
+            current_len, new_len, "try_fast_path: no fast path detected, falling back to full sync"
+        );
+        FastPathResult::NeedFullSync
+    }
+
+    /// Checks if the prefix of the new items matches the current queue items.
+    /// Uses local metadata cache or falls back to URI comparison.
+    fn check_prefix_matches(&self, current_ids: &[u32], new_items: &[PlaybackItem]) -> bool {
+        if current_ids.len() != new_items.len() {
+            return false;
+        }
+
+        let metadata_cache = match self.metadata_cache.lock() {
+            Ok(cache) => cache,
+            Err(_) => return false,
+        };
+
+        let uri_cache = match self.uri_by_id.lock() {
+            Ok(cache) => cache,
+            Err(_) => return false,
+        };
+
+        for (idx, new_item) in new_items.iter().enumerate() {
+            let current_id = current_ids[idx];
+
+            // First check if we have cached metadata for this track_id that matches
+            if let Some(cached_metadata) = metadata_cache.get(&current_id) {
+                if let Some(cached) = cached_metadata {
+                    // Compare using title + artist as identity (for streams)
+                    if let Some(ref new_metadata) = new_item.metadata {
+                        let same_title = cached.title.as_ref() == new_metadata.title.as_ref();
+                        let same_artist = cached.artist.as_ref() == new_metadata.artist.as_ref();
+                        if same_title && same_artist {
+                            continue;
+                        }
+                    }
+                }
+            }
+
+            // No metadata match - fall back to URI comparison using uri_by_id cache
+            if new_item.uri.is_empty() {
+                return false;
+            }
+
+            // Compare against cached URI for this track_id
+            if let Some(cached_uri) = uri_cache.get(&current_id) {
+                if cached_uri == &new_item.uri {
+                    continue;
+                }
+            }
+
+            // No match found - fall back to full sync
+            return false;
+        }
+
+        true
    }

    /// Met à jour les métadonnées d'un item de la queue à l'index spécifié.
@@ -250,7 +374,7 @@ impl OpenHomeQueue {
        metadata: Option<crate::model::TrackMetadata>,
    ) -> Result<(), ControlPointError> {
        let track_id = self.position_to_id(index)?;
-        self.cache_metadata(track_id, metadata);
+        self.cache_metadata(track_id, metadata, "");
        Ok(())
    }

@@ -260,8 +384,19 @@ impl OpenHomeQueue {
    /// chanson donc toute durée est acceptée.
    /// Pour les fichiers normaux (non-streams), les métadonnées sont acceptées telles quelles.
    /// Cette fonction est le SEUL point d'entrée pour modifier le cache.
-    fn cache_metadata(&self, track_id: u32, new_metadata: Option<crate::model::TrackMetadata>) {
+    fn cache_metadata(
+        &self,
+        track_id: u32,
+        new_metadata: Option<crate::model::TrackMetadata>,
+        uri: &str,
+    ) {
        let mut cache = self.metadata_cache.lock().unwrap();
+        let mut uri_cache = self.uri_by_id.lock().unwrap();
+
+        // Update URI cache
+        if !uri.is_empty() {
+            uri_cache.insert(track_id, uri.to_string());
+        }

        // Vérifier s'il y a déjà des métadonnées en cache
        if let Some(cached_meta) = cache.get(&track_id) {
@@ -366,7 +501,7 @@ impl OpenHomeQueue {
                );
                drop(cache); // Libérer le lock avant d'appeler cache_metadata
                             // Mettre en cache pour éviter les oscillations sur les flux radio
-                self.cache_metadata(entry.id, fresh.clone());
+                self.cache_metadata(entry.id, fresh.clone(), entry.uri());
                fresh
            }
        };
@@ -397,7 +532,7 @@ impl OpenHomeQueue {
            .insert(after_id, &item.uri, &metadata_xml)?;

        // Enregistrer les métadonnées dans le cache
-        self.cache_metadata(new_id, item.metadata);
+        self.cache_metadata(new_id, item.metadata, &item.uri);

        Ok(new_id)
    }
@@ -409,32 +544,44 @@ impl OpenHomeQueue {
        &mut self,
        new_items: Vec<PlaybackItem>,
        playing_id: usize,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: &mut Option<Box<dyn FnOnce() + Send>>,
    ) -> Result<(), ControlPointError> {
-        // Get current track IDs from OpenHome
+        use std::sync::atomic::Ordering::SeqCst;
+
        let current_track_ids = self.track_ids()?;

-        // Delete everything except the currently playing item
-        // Using delete_id_if_exists() to handle cases where another control point
-        // may have already modified the playlist
        for &track_id in current_track_ids.iter().rev() {
+            if cancel_token.load(SeqCst) {
+                return Err(ControlPointError::SyncCancelled);
+            }
            if track_id as usize != playing_id {
                self.playlist_client.delete_id_if_exists(track_id)?;
                self.metadata_cache.lock().unwrap().remove(&track_id);
            }
        }

-        // Insert new items after the currently playing track
        let mut previous_id = playing_id as u32;
+        let mut first_insert_done = false;
        for item in new_items {
+            if cancel_token.load(SeqCst) {
+                return Err(ControlPointError::SyncCancelled);
+            }
            let metadata = build_metadata_xml(&item);
            let new_id = self
                .playlist_client
                .insert(previous_id, &item.uri, &metadata)?;

-            // Enregistrer les métadonnées dans le cache
-            self.cache_metadata(new_id, item.metadata);
+            self.cache_metadata(new_id, item.metadata, &item.uri);

            previous_id = new_id;
+
+            if !first_insert_done && on_ready.is_some() {
+                first_insert_done = true;
+                if let Some(f) = on_ready.take() {
+                    f();
+                }
+            }
        }

        debug!(
@@ -442,7 +589,6 @@ impl OpenHomeQueue {
            "Gentle sync completed: preserved playing track as first item (not in new playlist)"
        );

-        // Invalidate cache after playlist modifications
        self.invalidate_track_caches();

        Ok(())
@@ -454,8 +600,13 @@ impl OpenHomeQueue {
        old_ids: &[u32],
        keep_flags: &[bool],
        position_label: &str,
+        cancel_token: &Arc<AtomicBool>,
    ) -> Result<(), ControlPointError> {
+        use std::sync::atomic::Ordering::SeqCst;
        for (idx, &track_id) in old_ids.iter().enumerate().rev() {
+            if cancel_token.load(SeqCst) {
+                return Err(ControlPointError::SyncCancelled);
+            }
            if !keep_flags[idx] {
                debug!(
                    renderer = self.renderer_id.0.as_str(),
@@ -480,8 +631,11 @@ impl OpenHomeQueue {
        keep_old_flags: &[bool],
        mut previous_id: u32,
        position_label: &str,
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: &mut Option<Box<dyn FnOnce() + Send>>,
    ) -> Result<u32, ControlPointError> {
-        // Collect IDs of kept items (in order)
+        use std::sync::atomic::Ordering::SeqCst;
+
        let remaining_ids: Vec<u32> = old_ids
            .iter()
            .enumerate()
@@ -489,16 +643,18 @@ impl OpenHomeQueue {
            .collect();

        let mut remaining_idx = 0;
+        let mut first_insert_done = false;

-        // Rebuild section
        for (idx, item) in new_items.iter().enumerate() {
+            if cancel_token.load(SeqCst) {
+                return Err(ControlPointError::SyncCancelled);
+            }
            if keep_new_flags[idx] {
                let existing_id = remaining_ids[remaining_idx];
                remaining_idx += 1;
                previous_id = existing_id;

-                // Mettre à jour les métadonnées de l'item existant conservé
-                self.cache_metadata(existing_id, item.metadata.clone());
+                self.cache_metadata(existing_id, item.metadata.clone(), &item.uri);

                debug!(
                    renderer = self.renderer_id.0.as_str(),
@@ -513,8 +669,7 @@ impl OpenHomeQueue {
                    .playlist_client
                    .insert(previous_id, &item.uri, &metadata)?;

-                // Enregistrer les métadonnées du nouvel item
-                self.cache_metadata(new_id, item.metadata.clone());
+                self.cache_metadata(new_id, item.metadata.clone(), &item.uri);

                debug!(
                    renderer = self.renderer_id.0.as_str(),
@@ -526,6 +681,13 @@ impl OpenHomeQueue {
                    new_id
                );
                previous_id = new_id;
+
+                if !first_insert_done && on_ready.is_some() {
+                    first_insert_done = true;
+                    if let Some(f) = on_ready.take() {
+                        f();
+                    }
+                }
            }
        }

@@ -542,6 +704,8 @@ impl OpenHomeQueue {
        pivot_id: usize,
        snapshot: &QueueSnapshot,
        current_track_ids: &[u32],
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: &mut Option<Box<dyn FnOnce() + Send>>,
    ) -> Result<(), ControlPointError> {
        // Find the pivot index in our current state
        let pivot_idx = current_track_ids
@@ -570,10 +734,15 @@ impl OpenHomeQueue {
        let (keep_old_before, keep_new_before) = lcs_flags_optimized(&old_before, new_before);

        // Delete items marked for deletion in AFTER part (reverse order)
-        self.delete_marked_items(&old_ids_after, &keep_old_after, "AFTER pivot")?;
+        self.delete_marked_items(&old_ids_after, &keep_old_after, "AFTER pivot", cancel_token)?;

        // Delete items marked for deletion in BEFORE part (reverse order)
-        self.delete_marked_items(&old_ids_before, &keep_old_before, "BEFORE pivot")?;
+        self.delete_marked_items(
+            &old_ids_before,
+            &keep_old_before,
+            "BEFORE pivot",
+            cancel_token,
+        )?;

        // Rebuild the playlist: [BEFORE, PIVOT, AFTER]
        // Rebuild BEFORE part (we don't need the returned previous_id)
@@ -584,13 +753,19 @@ impl OpenHomeQueue {
            &keep_old_before,
            OPENHOME_PLAYLIST_HEAD_ID,
            "BEFORE pivot",
+            cancel_token,
+            on_ready,
        )?;

        // PIVOT keeps its ID and position - it's the anchor point
        let previous_id = pivot_id as u32;

        // Mettre à jour les métadonnées du pivot
-        self.cache_metadata(previous_id, new_items[pivot_idx_new].metadata.clone());
+        self.cache_metadata(
+            previous_id,
+            new_items[pivot_idx_new].metadata.clone(),
+            &new_items[pivot_idx_new].uri,
+        );

        debug!(
            renderer = self.renderer_id.0.as_str(),
@@ -609,6 +784,8 @@ impl OpenHomeQueue {
            &keep_old_after,
            previous_id,
            "AFTER pivot",
+            cancel_token,
+            on_ready,
        )?;

        debug!(
@@ -630,7 +807,11 @@ impl OpenHomeQueue {
        items: Vec<PlaybackItem>,
        snapshot: &QueueSnapshot,
        current_track_ids: &[u32],
+        cancel_token: &Arc<AtomicBool>,
+        on_ready: &mut Option<Box<dyn FnOnce() + Send>>,
    ) -> Result<(), ControlPointError> {
+        use std::sync::atomic::Ordering::SeqCst;
+
        debug!(
            renderer = self.renderer_id.0.as_str(),
            current_count = snapshot.items.len(),
@@ -656,32 +837,22 @@ impl OpenHomeQueue {
            "LCS computed: minimizing OpenHome playlist operations"
        );

-        // Get current playing track ID BEFORE any modifications
        let current_track_id = self.playlist_client.id().ok().filter(|&id| id != 0);

-        // Check if the currently playing track is in the new playlist
-        // If so, we should NOT use delete_all() - we must preserve it
        let current_track_in_new_playlist = current_track_id.and_then(|current_id| {
            items
                .iter()
                .position(|item| item.backend_id as u32 == current_id)
        });

-        // If we're replacing everything (keep=0), use delete_all() BUT only if
-        // there's no currently playing track, OR if the current track is not in the new playlist.
-        // If current track IS in new playlist, we must preserve it using insert/delete operations.
        if items_to_keep == 0 && items_to_delete > 0 {
            if current_track_in_new_playlist.is_some() {
-                // Current track is in new playlist - use insert/delete instead of delete_all
-                // to preserve playback
                debug!(
                    renderer = self.renderer_id.0.as_str(),
                    current_track_in_playlist = true,
                    "Preserving currently playing track - using insert/delete instead of delete_all"
                );
-                // Fall through to selective deletion below
            } else {
-                // No current track or not in new playlist - safe to use delete_all
                debug!(
                    renderer = self.renderer_id.0.as_str(),
                    "Using delete_all() for complete replacement (safe - no current track or not in new playlist)"
@@ -690,19 +861,18 @@ impl OpenHomeQueue {
                self.metadata_cache.lock().unwrap().clear();
            }
        } else {
-            // Selective deletion when keeping some items
            for idx in (0..current_track_ids.len()).rev() {
+                if cancel_token.load(SeqCst) {
+                    return Err(ControlPointError::SyncCancelled);
+                }
                if !keep_current[idx] {
                    let track_id = current_track_ids[idx];
-                    // Use delete_id_if_exists() to handle cases where another control point
-                    // may have already modified the playlist
                    self.playlist_client.delete_id_if_exists(track_id)?;
                    self.metadata_cache.lock().unwrap().remove(&track_id);
                }
            }
        }

-        // Rebuild by inserting new items
        let remaining_ids: Vec<u32> = current_track_ids
            .iter()
            .enumerate()
@@ -717,8 +887,12 @@ impl OpenHomeQueue {

        let mut remaining_idx = 0usize;
        let mut previous_id = OPENHOME_PLAYLIST_HEAD_ID;
+        let mut first_insert_done = false;

        for (idx, item) in items.into_iter().enumerate() {
+            if cancel_token.load(SeqCst) {
+                return Err(ControlPointError::SyncCancelled);
+            }
            if keep_desired[idx] {
                if remaining_idx >= remaining_ids.len() {
                    return Err(ControlPointError::OpenHomeError(format!(
@@ -729,19 +903,23 @@ impl OpenHomeQueue {
                remaining_idx += 1;
                previous_id = existing_id;

-                // Mettre à jour les métadonnées de l'item existant conservé
-                // La fonction cache_metadata gère la protection contre la diminution de durée
-                self.cache_metadata(existing_id, item.metadata);
+                self.cache_metadata(existing_id, item.metadata, &item.uri);
            } else {
                let metadata = build_metadata_xml(&item);
                let new_id = self
                    .playlist_client
                    .insert(previous_id, &item.uri, &metadata)?;

-                // Enregistrer les métadonnées du nouvel item
-                self.cache_metadata(new_id, item.metadata);
+                self.cache_metadata(new_id, item.metadata, &item.uri);

                previous_id = new_id;
+
+                if !first_insert_done && on_ready.is_some() {
+                    first_insert_done = true;
+                    if let Some(f) = on_ready.take() {
+                        f();
+                    }
+                }
            }
        }

@@ -751,7 +929,6 @@ impl OpenHomeQueue {
            )));
        }

-        // Invalidate cache after playlist modifications
        self.invalidate_track_caches();

        Ok(())
@@ -1124,7 +1301,7 @@ impl QueueBackend for OpenHomeQueue {
                .insert(previous_id, &item.uri, &metadata)?;

            // Enregistrer les métadonnées dans le cache
-            self.cache_metadata(new_id, item.metadata);
+            self.cache_metadata(new_id, item.metadata, &item.uri);

            previous_id = new_id;
        }
@@ -1135,10 +1312,20 @@ impl QueueBackend for OpenHomeQueue {
        Ok(())
    }

-    fn sync_queue(&mut self, items: Vec<PlaybackItem>) -> Result<(), ControlPointError> {
+    fn sync_queue(
+        &mut self,
+        items: Vec<PlaybackItem>,
+        cancel_token: &Arc<AtomicBool>,
+        mut on_ready: Option<Box<dyn FnOnce() + Send>>,
+    ) -> Result<(), ControlPointError> {
+        use std::sync::atomic::Ordering::SeqCst;
+
        self.ensure_playlist_source_selected()?;

-        // DIAGNOSTIC: Log current track state before any modifications
+        if cancel_token.load(SeqCst) {
+            return Err(ControlPointError::SyncCancelled);
+        }
+
        let pre_current_track = self.playlist_client.id().ok();
        tracing::warn!(
            renderer = self.renderer_id.0.as_str(),
@@ -1154,10 +1341,8 @@ impl QueueBackend for OpenHomeQueue {
            );
            self.playlist_client.delete_all()?;
            self.metadata_cache.lock().unwrap().clear();
-            // Invalidate caches after delete_all (clears queue and current track)
            self.invalidate_all_caches();

-            // DIAGNOSTIC: Log state after delete_all
            let post_current_track = self.playlist_client.id().ok();
            tracing::warn!(
                renderer = self.renderer_id.0.as_str(),
@@ -1167,9 +1352,58 @@ impl QueueBackend for OpenHomeQueue {
            return Ok(());
        }

-        // Synchronize local state with the actual OpenHome playlist before computing
-        // differences. Without this, any drift between our cache and the renderer
-        // (e.g., manual edits from another control point) would keep the stale items.
+        match self.try_fast_path(&items) {
+            FastPathResult::AppendOnly { new_items } => {
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    new_items_count = new_items.len(),
+                    "sync_queue: fast path - append-only detected"
+                );
+                let current_ids = self.track_ids()?;
+                let mut after_id = current_ids
+                    .last()
+                    .copied()
+                    .unwrap_or(OPENHOME_PLAYLIST_HEAD_ID);
+                let mut uri_cache = self.uri_by_id.lock().unwrap();
+                for item in &new_items {
+                    if cancel_token.load(SeqCst) {
+                        return Err(ControlPointError::SyncCancelled);
+                    }
+                    let metadata = build_metadata_xml(item);
+                    let uri = item.uri.as_str();
+                    let metadata_xml = metadata.as_str();
+                    after_id = self.playlist_client.insert(after_id, uri, metadata_xml)?;
+                    if !item.uri.is_empty() {
+                        uri_cache.insert(after_id, item.uri.clone());
+                    }
+                }
+                drop(uri_cache);
+                self.invalidate_track_caches();
+                return Ok(());
+            }
+            FastPathResult::DeleteFromEnd { delete_ids } => {
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    delete_count = delete_ids.len(),
+                    "sync_queue: fast path - delete-from-end detected"
+                );
+                for id in delete_ids.iter().rev() {
+                    if cancel_token.load(SeqCst) {
+                        return Err(ControlPointError::SyncCancelled);
+                    }
+                    self.playlist_client.delete_id(*id)?;
+                }
+                self.invalidate_all_caches();
+                return Ok(());
+            }
+            FastPathResult::NeedFullSync => {
+                debug!(
+                    renderer = self.renderer_id.0.as_str(),
+                    "sync_queue: fast path not applicable, proceeding with full sync"
+                );
+            }
+        }
+
        let snapshot = self.queue_snapshot()?;

        debug!(
@@ -1180,9 +1414,6 @@ impl QueueBackend for OpenHomeQueue {
            "sync_queue: snapshot vs new items comparison"
        );

-        // Note: current_index may point to an index that doesn't exist in items
-        // if the OpenHome renderer is in an inconsistent state (e.g., IdArray returns
-        // IDs but ReadList returns empty TrackList). We must bounds-check here.
        let playing_info = snapshot.current_index.and_then(|idx| {
            if idx < snapshot.items.len() {
                Some((
@@ -1209,8 +1440,14 @@ impl QueueBackend for OpenHomeQueue {
            "OpenHome playlist state"
        );

+        let has_pivot = playing_info.is_some();
+        if has_pivot {
+            if let Some(f) = on_ready.take() {
+                f();
+            }
+        }
+
        if let Some((playing_idx, playing_id, playing_uri, playing_didl_id)) = playing_info {
-            // Find if the currently playing item is in the new playlist (by URI first, then by didl_id)
            let new_playing_idx = items
                .iter()
                .position(|item| item.uri == playing_uri)
@@ -1230,8 +1467,6 @@ impl QueueBackend for OpenHomeQueue {
            );

            if let Some(pivot_idx) = new_playing_idx {
-                // CASE 2: Currently playing item IS in the new playlist
-                // Use gentle double-LCS strategy: preserve the pivot and sync before/after separately
                debug!(
                    renderer = self.renderer_id.0.as_str(),
                    playing_idx,
@@ -1248,22 +1483,24 @@ impl QueueBackend for OpenHomeQueue {
                    playing_id,
                    &snapshot,
                    &current_ids_for_pivot,
+                    cancel_token,
+                    &mut on_ready,
                )?;
            } else {
-                // CASE 1: Currently playing item NOT in the new playlist
-                // Keep it as first item and append the new playlist after it
                debug!(
                    renderer = self.renderer_id.0.as_str(),
                    playing_idx,
                    "Gentle sync: currently playing item not in new playlist, preserving as first item"
                );

-                self.replace_queue_preserve_current(items, playing_id)?;
+                self.replace_queue_preserve_current(
+                    items,
+                    playing_id,
+                    cancel_token,
+                    &mut on_ready,
+                )?;
            }
        } else {
-            // No currently playing item or can't determine it - use standard LCS
-            // BUT first check if this is because the OpenHome device returned empty playlist
-            // This could cause the queue to be cleared incorrectly
            if snapshot.items.is_empty() && !items.is_empty() {
                tracing::warn!(
                    renderer = self.renderer_id.0.as_str(),
@@ -1271,8 +1508,6 @@ impl QueueBackend for OpenHomeQueue {
                    new_items = items.len(),
                    "OpenHome playlist appears empty - possible stale cache or device issue, NOT clearing queue"
                );
-                // Don't call replace_queue_standard_lcs with empty snapshot - it would clear our queue
-                // Instead, just add the new items without deleting existing ones
                return self.enqueue_items(items, crate::queue::EnqueueMode::AppendToEnd);
            }

@@ -1282,10 +1517,15 @@ impl QueueBackend for OpenHomeQueue {
            );
            let current_ids_for_lcs: Vec<u32> =
                snapshot.items.iter().map(|i| i.backend_id as u32).collect();
-            self.replace_queue_standard_lcs(items, &snapshot, &current_ids_for_lcs)?;
+            self.replace_queue_standard_lcs(
+                items,
+                &snapshot,
+                &current_ids_for_lcs,
+                cancel_token,
+                &mut on_ready,
+            )?;
        }

-        // DIAGNOSTIC: Log state after sync completes
        let post_current_track = self.playlist_client.id().ok();
        let post_ids = self.track_ids();
        tracing::warn!(
@@ -1344,7 +1584,8 @@ impl QueueBackend for OpenHomeQueue {

        // Mettre à jour le cache avec les nouvelles métadonnées
        self.metadata_cache.lock().unwrap().remove(&track_id);
-        self.cache_metadata(new_id, item.metadata);
+        self.uri_by_id.lock().unwrap().remove(&track_id);
+        self.cache_metadata(new_id, item.metadata, &item.uri);

        if ci == Some(index) {
            self.playlist_client.seek_id(new_id)?;
@@ -1503,6 +1744,6 @@ impl QueueFromRendererInfo for OpenHomeQueue {
    }

    fn to_backend(self) -> MusicQueue {
-        MusicQueue::OpenHome(self)
+        MusicQueue::from_openhome(self)
    }
 }
--- a/pmocontrol/src/queue/snapshot.rs
+++ b/pmocontrol/src/queue/snapshot.rs
@@ -1,4 +1,4 @@
-use crate::{DeviceId, model::TrackMetadata};
+use crate::{model::TrackMetadata, DeviceId};

 /// Canonical representation of a track in a renderer queue.
 ///
--- a/pmocontrol/src/registry.rs
+++ b/pmocontrol/src/registry.rs
@@ -136,6 +136,14 @@ impl DeviceRegistry {
        self.devices.get(id)?.as_music_renderer().ok()
    }

+    pub fn get_renderer_queue_arc(
+        &self,
+        id: &DeviceId,
+    ) -> Option<std::sync::Arc<std::sync::Mutex<crate::queue::MusicQueue>>> {
+        let renderer = self.get_renderer(id)?;
+        Some(renderer.queue())
+    }
+
    pub fn get_server(&self, id: &DeviceId) -> Option<Arc<MusicServer>> {
        self.devices.get(id)?.as_music_server().ok()
    }
--- a/pmocontrol/src/soap_client.rs
+++ b/pmocontrol/src/soap_client.rs
@@ -1,12 +1,30 @@
+use std::sync::Arc;
+use std::sync::OnceLock;
 use std::time::Duration;

 use anyhow::{Context, Result};
-use pmoupnp::soap::{SoapEnvelope, build_soap_request, parse_soap_envelope};
+use pmoupnp::soap::{build_soap_request, parse_soap_envelope, SoapEnvelope};
 use tracing::{debug, trace, warn};
 use ureq::Agent;

 use crate::errors::ControlPointError;

+static SOAP_AGENT: OnceLock<Arc<Agent>> = OnceLock::new();
+
+fn get_soap_agent() -> Arc<Agent> {
+    SOAP_AGENT
+        .get_or_init(|| {
+            Arc::new(
+                Agent::config_builder()
+                    .http_status_as_error(false)
+                    .timeout_global(Some(Duration::from_secs(30)))
+                    .build()
+                    .into(),
+            )
+        })
+        .clone()
+}
+
 /// Result of a SOAP call:
 /// - HTTP status code
 /// - raw XML body (always)
@@ -62,21 +80,20 @@ pub fn invoke_upnp_action_with_timeout(

    trace!(body = body_xml.as_str(), "SOAP request body");

-    let mut builder = Agent::config_builder();
-    builder = builder.http_status_as_error(false);
-    if let Some(duration) = timeout {
-        builder = builder.timeout_global(Some(duration));
-    }
+    let request = if let Some(duration) = timeout {
+        let config = Agent::config_builder()
+            .http_status_as_error(false)
+            .timeout_global(Some(duration))
+            .build();
+        let agent: Agent = config.into();
+        agent.post(control_url)
+    } else {
+        get_soap_agent().post(control_url)
+    };

-    let config = builder.build();
-    let agent: Agent = config.into();
-
-    // 3. SOAPAction header
    let soap_action_header = format!(r#""{}#{}""#, service_type, action);

-    // 4. HTTP POST
-    let mut response = agent
-        .post(control_url)
+    let mut response = request
        .header("Content-Type", r#"text/xml; charset="utf-8""#)
        .header("SOAPAction", &soap_action_header)
        .send(body_xml)
--- a/pmocontrol/src/sse.rs
+++ b/pmocontrol/src/sse.rs
@@ -153,6 +153,14 @@ pub enum RendererEventPayload {
        renderer_id: String,
        timestamp: chrono::DateTime<chrono::Utc>,
    },
+    QueueReadyToPlay {
+        renderer_id: String,
+        timestamp: chrono::DateTime<chrono::Utc>,
+    },
+    QueueSyncCancelled {
+        renderer_id: String,
+        timestamp: chrono::DateTime<chrono::Utc>,
+    },
    BindingChanged {
        renderer_id: String,
        server_id: Option<String>,
@@ -293,6 +301,14 @@ async fn renderer_event_to_payload(
            renderer_id: id.0,
            timestamp,
        },
+        RendererEvent::QueueReadyToPlay { id } => RendererEventPayload::QueueReadyToPlay {
+            renderer_id: id.0,
+            timestamp,
+        },
+        RendererEvent::QueueSyncCancelled { id } => RendererEventPayload::QueueSyncCancelled {
+            renderer_id: id.0,
+            timestamp,
+        },
        RendererEvent::BindingChanged { id, binding } => RendererEventPayload::BindingChanged {
            renderer_id: id.0,
            server_id: binding.as_ref().map(|b| b.server_id.0.clone()),
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.3.40
+0.3.41
@@ -1 +1 @@
 .3.40
 .3.41