def _get_repr_html_ffmpeg(images: List[PilImage]) -> str:
"""Runs ffmpeg to get the mp4 encoded <video> str."""
# Find number of digits in len to give names.
num_digits = len(str(len(images))) + 1
with tempfile.TemporaryDirectory() as video_dir:
for i, img in enumerate(images):
f = os.path.join(video_dir, f'img{i:0{num_digits}d}.png')
img.save(f, format='png')
ffmpeg_args = [
'-framerate', str(_VISU_FRAMERATE),
'-i', os.path.join(video_dir, f'img%0{num_digits}d.png'),
# Using native h264 to encode video stream to H.264 codec
# Default encoding does not seems to be supported by chrome.
'-vcodec', 'h264',
# When outputting H.264, `-pix_fmt yuv420p` maximize compatibility
# with bad video players.
# Ref: https://trac.ffmpeg.org/wiki/Slideshow
'-pix_fmt', 'yuv420p',
# Native encoder cannot encode images of small scale
# or the the hardware encoder may be busy which raises
# Error: cannot create compression session
# so allow software encoding
# '-allow_sw', '1',
]
video_path = utils.as_path(video_dir) / 'output.mp4'
ffmpeg_args.append(os.fspath(video_path))
utils.ffmpeg_run(ffmpeg_args)
video_str = utils.get_base64(video_path.read_bytes())
return (
f'<video height="{THUMBNAIL_SIZE}" width="175" '
'controls loop autoplay muted playsinline>'
f'<source src="data:video/mp4;base64,{video_str}" type="video/mp4" >'
'</video>'
)
def make_video_repr_html(ex, *, use_colormap: bool):
"""Returns the encoded `<video>` or GIF <img/> HTML."""
# Use GIF to generate a HTML5 compatible video if FFMPEG is not
# installed on the system.
images = [_create_thumbnail(frame, use_colormap=use_colormap) for frame in ex]
if not images:
return 'Video with 0 frames.'
# Display the video HTML (either GIF of mp4 if ffmpeg is installed)
try:
utils.ffmpeg_run(['-version']) # Check for ffmpeg installation.
except FileNotFoundError:
# print as `stderr` is displayed poorly on Colab
print('FFMPEG not detected. Falling back on GIF.')
return _get_repr_html_gif(images)
else:
return _get_repr_html_ffmpeg(images)
def _ffmpeg_decode(self, path_or_fobj):
if isinstance(path_or_fobj, type_utils.PathLikeCls):
ffmpeg_args = ['-i', os.fspath(path_or_fobj)]
ffmpeg_stdin = None
else:
ffmpeg_args = ['-i', 'pipe:0']
ffmpeg_stdin = path_or_fobj.read()
ffmpeg_args += self._extra_ffmpeg_args
with tempfile.TemporaryDirectory() as ffmpeg_dir:
out_pattern = os.path.join(ffmpeg_dir,
f'%010d.{self._encoding_format}')
ffmpeg_args.append(out_pattern)
utils.ffmpeg_run(ffmpeg_args, ffmpeg_stdin)
frames = [ # Load all encoded images
p.read_bytes()
for p in sorted(utils.as_path(ffmpeg_dir).iterdir())
]
return frames
