Merge pull request #411 from saimn/video-thumbnail

Fix video thumbnail creation when delay > video length

.github/workflows/python-tests.yml

@@ -28,6 +28,7 @@ jobs:
         python-version: ${{ matrix.python-version }}
     - name: Install FFmpeg
       run: |
+        sudo apt update
         sudo apt install ffmpeg
         ffmpeg -version
     - name: Install Tox

docs/changelog.rst

@@ -11,6 +11,7 @@ Released on 2020-xx-xx.
 - Catch warnings when reading EXIF data.
 - Avoid crash when thumbnail cannot be generated [:issue:`401`].
 - Replace deprecated usage of `imp`.
+- Fix video thumbnail creation when delay > video length [:issue:`411`].
 
 Version 2.1.1
 ~~~~~~~~~~~~~

sigal/video.py

@@ -136,10 +136,21 @@ def generate_thumbnail(source, outname, box, delay, fit=True, options=None,
 
     # dump an image of the video
     cmd = [converter, '-i', source, '-an', '-r', '1',
-           '-ss', delay, '-vframes', '1', '-y', tmpfile]
+           '-ss', str(delay), '-vframes', '1', '-y', tmpfile]
     logger.debug('Create thumbnail for video: %s', ' '.join(cmd))
     check_subprocess(cmd, source, outname)
 
+    # Sometimes ffmpeg fails with returncode zero but without producing an
+    # output file Thus, we need to check if an output file was created. If
+    # not, assume ffmpeg failed
+    if not os.path.isfile(tmpfile):
+        logger.debug('Thumbnail generation failed. Likely due to very short '
+                     'video length.')
+        cmd = [converter, '-i', source, '-an', '-r', '1',
+               '-ss', '0', '-vframes', '1', '-y', tmpfile]
+        logger.debug('Retry to create thumbnail for video: %s', ' '.join(cmd))
+        check_subprocess(cmd, source, outname)
+
     # use the generate_thumbnail function from sigal.image
     image.generate_thumbnail(tmpfile, outname, box, fit=fit, options=options)
     # remove the image

tests/sample/sigal.conf.py

@@ -3,6 +3,7 @@ title = 'Sigal test gallery ☺'
 source = 'pictures'
 thumb_suffix = '.tn'
 keep_orig = True
+thumb_video_delay = 5
 
 links = [('Example link', 'http://example.org'),
          ('Another link', 'http://example.org')]

tests/test_video.py

@@ -3,7 +3,8 @@ import os
 import pytest
 
 from sigal.settings import Status, create_settings
-from sigal.video import generate_video, process_video, video_size
+from sigal.video import (generate_thumbnail, generate_video, process_video,
+                         video_size)
 
 CURRENT_DIR = os.path.dirname(__file__)
 TEST_VIDEO = 'example video.ogv'
@@ -17,6 +18,12 @@ def test_video_size():
     assert size_src == (0, 0)
 
 
+def test_generate_thumbnail(tmpdir):
+    outname = str(tmpdir.join('test.jpg'))
+    generate_thumbnail(SRCFILE, outname, (50, 50), 5)
+    assert os.path.isfile(outname)
+
+
 def test_process_video(tmpdir):
     base, ext = os.path.splitext(TEST_VIDEO)
 
@@ -48,7 +55,7 @@ def test_generate_video_fit_height(tmpdir, fmt):
 
     assert size_dst[0] == 80
     # less than 2% error on ratio
-    assert abs(size_dst[0]/size_dst[1] - size_src[0]/size_src[1]) < 2e-2
+    assert abs(size_dst[0] / size_dst[1] - size_src[0] / size_src[1]) < 2e-2
 
 
 @pytest.mark.parametrize("fmt", ['webm', 'mp4'])
@@ -66,7 +73,7 @@ def test_generate_video_fit_width(tmpdir, fmt):
 
     assert size_dst[1] == 50
     # less than 2% error on ratio
-    assert abs(size_dst[0]/size_dst[1] - size_src[0]/size_src[1]) < 2e-2
+    assert abs(size_dst[0] / size_dst[1] - size_src[0] / size_src[1]) < 2e-2
 
 
 @pytest.mark.parametrize("fmt", ['webm', 'mp4', 'ogv'])