Ajout d'un decodeur ogg et opus vers pcm

This commit is contained in:
2025-10-27 19:25:51 +01:00
parent 6b52b6ffee
commit b7661b5767
10 changed files with 1280 additions and 203 deletions

413
pmoflac/src/opus.rs Normal file
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//! # Ogg/Opus Decoder Module
//!
//! Streaming decoder for Ogg-wrapped Opus audio. This reuses the common async
//! ingestion/producer pattern established for the other decoders while staying
//! 100% streaming (no seeking or buffering entire files).
use std::{
io::{self, Read},
pin::Pin,
task::{Context, Poll},
};
use opus::{Channels, Decoder as OpusDecoder, Error as OpusError};
use tokio::{
io::{AsyncRead, ReadBuf},
sync::{mpsc, oneshot},
};
use crate::{
common::ChannelReader,
decoder_common::{
spawn_ingest_task, spawn_writer_task, CHANNEL_CAPACITY, DUPLEX_BUFFER_SIZE,
},
pcm::StreamInfo,
stream::ManagedAsyncReader,
};
/// Maximum number of samples per Opus frame at 48 kHz (120 ms).
const MAX_FRAME_SAMPLES: usize = 5760;
/// Errors that can occur while decoding Ogg/Opus data.
#[derive(thiserror::Error, Debug, Clone)]
pub enum OggOpusError {
#[error("I/O error ({kind:?}): {message}")]
Io {
kind: io::ErrorKind,
message: String,
},
#[error("Ogg/Opus decode error: {0}")]
Decode(String),
#[error("internal channel closed unexpectedly")]
ChannelClosed,
}
impl From<io::Error> for OggOpusError {
fn from(err: io::Error) -> Self {
OggOpusError::Io {
kind: err.kind(),
message: err.to_string(),
}
}
}
impl From<OpusError> for OggOpusError {
fn from(err: OpusError) -> Self {
OggOpusError::Decode(err.to_string())
}
}
impl From<String> for OggOpusError {
fn from(value: String) -> Self {
OggOpusError::Decode(value)
}
}
/// An async stream that decodes Ogg/Opus audio into PCM samples.
pub struct OggOpusDecodedStream {
info: StreamInfo,
reader: ManagedAsyncReader<OggOpusError>,
}
impl OggOpusDecodedStream {
/// Returns metadata about the decoded stream.
pub fn info(&self) -> &StreamInfo {
&self.info
}
/// Consumes the stream and returns its components.
pub fn into_parts(self) -> (StreamInfo, ManagedAsyncReader<OggOpusError>) {
(self.info, self.reader)
}
/// Waits for the decoding pipeline to finish.
pub async fn wait(self) -> Result<(), OggOpusError> {
self.reader.wait().await
}
}
impl AsyncRead for OggOpusDecodedStream {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.reader).poll_read(cx, buf)
}
}
/// Decodes an Ogg/Opus stream into PCM audio (16-bit little-endian).
pub async fn decode_ogg_opus_stream<R>(reader: R) -> Result<OggOpusDecodedStream, OggOpusError>
where
R: AsyncRead + Unpin + Send + 'static,
{
let (ingest_tx, ingest_rx) = mpsc::channel(CHANNEL_CAPACITY);
spawn_ingest_task::<_, OggOpusError>(reader, ingest_tx);
let (pcm_tx, pcm_rx) = mpsc::channel(CHANNEL_CAPACITY);
let (pcm_reader, pcm_writer) = tokio::io::duplex(DUPLEX_BUFFER_SIZE);
let (info_tx, info_rx) = oneshot::channel::<Result<StreamInfo, OggOpusError>>();
let blocking_handle = tokio::task::spawn_blocking(move || -> Result<(), OggOpusError> {
let channel_reader = ChannelReader::<OggOpusError>::new(ingest_rx);
let mut packet_reader = StreamingPacketReader::new(channel_reader);
let header_packet = packet_reader
.next_packet()?
.ok_or_else(|| OggOpusError::Decode("missing OpusHead packet".into()))?;
let header = OpusHead::parse(&header_packet)?;
let tags_packet = packet_reader
.next_packet()?
.ok_or_else(|| OggOpusError::Decode("missing OpusTags packet".into()))?;
let _tags = OpusTags::parse(&tags_packet)?;
let channels_enum = match header.channels {
1 => Channels::Mono,
2 => Channels::Stereo,
other => {
return Err(OggOpusError::Decode(format!(
"unsupported channel count: {}",
other
)))
}
};
let mut decoder = OpusDecoder::new(48_000, channels_enum)?;
if header.output_gain != 0 {
decoder.set_gain(i32::from(header.output_gain))?;
}
let info = StreamInfo {
sample_rate: 48_000,
channels: header.channels,
bits_per_sample: 16,
total_samples: None,
max_block_size: MAX_FRAME_SAMPLES as u16,
min_block_size: 0,
};
if info_tx.send(Ok(info.clone())).is_err() {
return Ok(());
}
let channels = header.channels as usize;
let mut pcm_buffer = vec![0i16; MAX_FRAME_SAMPLES * channels];
let mut pcm_bytes = Vec::new();
let mut pre_skip = header.pre_skip as usize;
let mut produced_audio = false;
while let Some(packet) = packet_reader.next_packet()? {
if pcm_buffer.len() < MAX_FRAME_SAMPLES * channels {
pcm_buffer
.resize(MAX_FRAME_SAMPLES * channels, 0);
}
let decoded_frames =
decoder.decode(&packet, &mut pcm_buffer[..MAX_FRAME_SAMPLES * channels], false)?;
if decoded_frames == 0 {
continue;
}
let mut start_frame = 0;
if pre_skip > 0 {
let drop = pre_skip.min(decoded_frames);
pre_skip -= drop;
start_frame = drop;
if start_frame == decoded_frames {
continue;
}
}
let start_index = start_frame * channels;
let end_index = decoded_frames * channels;
pcm_bytes.clear();
pcm_bytes.reserve((end_index - start_index) * 2);
for sample in &pcm_buffer[start_index..end_index] {
pcm_bytes.extend_from_slice(&sample.to_le_bytes());
}
if pcm_bytes.is_empty() {
continue;
}
produced_audio = true;
let chunk = pcm_bytes.clone();
if pcm_tx.blocking_send(Ok(chunk)).is_err() {
break;
}
}
if !produced_audio {
return Err(OggOpusError::Decode(
"stream contained no decodable Opus packets".into(),
));
}
Ok(())
});
let writer_handle = spawn_writer_task(pcm_rx, pcm_writer, blocking_handle, "ogg-opus");
let info = info_rx.await.map_err(|_| OggOpusError::ChannelClosed)??;
let reader = ManagedAsyncReader::new("ogg-opus-writer", pcm_reader, writer_handle);
Ok(OggOpusDecodedStream { info, reader })
}
/// Parsed OpusHead metadata.
struct OpusHead {
channels: u8,
pre_skip: u16,
output_gain: i16,
}
impl OpusHead {
fn parse(data: &[u8]) -> Result<Self, OggOpusError> {
if data.len() < 19 {
return Err(OggOpusError::Decode("OpusHead packet too short".into()));
}
if &data[0..8] != b"OpusHead" {
return Err(OggOpusError::Decode("invalid OpusHead signature".into()));
}
let version = data[8];
if version == 0 || version > 15 {
return Err(OggOpusError::Decode(format!(
"unsupported Opus version: {}",
version
)));
}
let channels = data[9];
if channels == 0 {
return Err(OggOpusError::Decode("Opus channel count must be > 0".into()));
}
let pre_skip = u16::from_le_bytes([data[10], data[11]]);
let _input_sample_rate = u32::from_le_bytes([data[12], data[13], data[14], data[15]]);
let output_gain = i16::from_le_bytes([data[16], data[17]]);
let channel_mapping = data[18];
if channel_mapping != 0 {
return Err(OggOpusError::Decode(
"non-default Opus channel mapping is unsupported".into(),
));
}
Ok(Self {
channels,
pre_skip,
output_gain,
})
}
}
/// Minimal parsing of OpusTags (metadata). We only validate the signature.
struct OpusTags;
impl OpusTags {
fn parse(data: &[u8]) -> Result<Self, OggOpusError> {
if data.len() < 8 || &data[0..8] != b"OpusTags" {
return Err(OggOpusError::Decode("invalid OpusTags header".into()));
}
Ok(OpusTags)
}
}
/// Streaming Ogg packet reader reused for Opus packets.
struct StreamingPacketReader<E>
where
E: std::error::Error + std::fmt::Display,
{
reader: ChannelReader<E>,
current_packet: Vec<u8>,
pending_packets: std::collections::VecDeque<Vec<u8>>,
finished: bool,
stream_serial: Option<u32>,
}
impl<E> StreamingPacketReader<E>
where
E: std::error::Error + std::fmt::Display,
{
fn new(reader: ChannelReader<E>) -> Self {
Self {
reader,
current_packet: Vec::new(),
pending_packets: std::collections::VecDeque::new(),
finished: false,
stream_serial: None,
}
}
fn next_packet(&mut self) -> Result<Option<Vec<u8>>, OggOpusError> {
loop {
if let Some(packet) = self.pending_packets.pop_front() {
return Ok(Some(packet));
}
if self.finished {
return Ok(None);
}
self.read_page()?;
}
}
fn read_page(&mut self) -> Result<(), OggOpusError> {
let mut header = [0u8; 27];
if !read_exact_or_eof(&mut self.reader, &mut header)? {
self.finished = true;
return Ok(());
}
if &header[0..4] != b"OggS" {
return Err(OggOpusError::Decode("invalid Ogg capture pattern".into()));
}
if header[4] != 0 {
return Err(OggOpusError::Decode("unsupported Ogg version".into()));
}
let header_type = header[5];
let bitstream_serial = u32::from_le_bytes([header[14], header[15], header[16], header[17]]);
if let Some(serial) = self.stream_serial {
if serial != bitstream_serial {
return Err(OggOpusError::Decode(
"multiple logical Ogg streams are unsupported".to_string(),
));
}
} else {
self.stream_serial = Some(bitstream_serial);
}
let page_segments = header[26] as usize;
let mut segment_table = vec![0u8; page_segments];
read_exact_checked(&mut self.reader, &mut segment_table)?;
let data_len: usize = segment_table.iter().map(|&v| v as usize).sum();
let mut data = vec![0u8; data_len];
read_exact_checked(&mut self.reader, &mut data)?;
if header_type & 0x01 != 0 && self.current_packet.is_empty() {
return Err(OggOpusError::Decode(
"continuation flag set without existing packet".into(),
));
}
if header_type & 0x01 == 0 && !self.current_packet.is_empty() {
return Err(OggOpusError::Decode(
"expected continuation flag for unfinished packet".into(),
));
}
let mut offset = 0usize;
for &seg_len in &segment_table {
let len = seg_len as usize;
let end = offset
.checked_add(len)
.ok_or_else(|| OggOpusError::Decode("segment length overflow".into()))?;
if end > data.len() {
return Err(OggOpusError::Decode("segment exceeds page data".into()));
}
self.current_packet.extend_from_slice(&data[offset..end]);
offset = end;
if seg_len < 255 {
let packet = std::mem::take(&mut self.current_packet);
self.pending_packets.push_back(packet);
}
}
if offset != data.len() {
return Err(OggOpusError::Decode("page data not fully consumed".into()));
}
if header_type & 0x04 != 0 && self.current_packet.is_empty() {
self.finished = true;
}
Ok(())
}
}
fn read_exact_or_eof<R: Read>(reader: &mut R, buf: &mut [u8]) -> io::Result<bool> {
let mut read = 0;
while read < buf.len() {
match reader.read(&mut buf[read..])? {
0 if read == 0 => return Ok(false),
0 => {
return Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
"unexpected EOF while reading",
))
}
n => read += n,
}
}
Ok(true)
}
fn read_exact_checked<R: Read>(reader: &mut R, buf: &mut [u8]) -> Result<(), OggOpusError> {
if !read_exact_or_eof(reader, buf)? {
return Err(OggOpusError::Decode("unexpected EOF in Ogg stream".into()));
}
Ok(())
}