On Mon, Jul 20, 2020 at 09:18:19PM +0100, Michael wrote: > I don't have this webcam so I don't know if it will or won't play nicely with > Linux, but at least ffmpeg seems to contain the requisite mjpeg codec: > > $ ffmpeg -hide_banner -codecs | grep mjpeg > DEVIL. mjpeg Motion JPEG (encoders: mjpeg mjpeg_vaapi ) > D.VIL. mjpegb Apple MJPEG-B > D.A.L. adpcm_ima_smjpeg ADPCM IMA Loki SDL MJPEG
MJPEG seems fully supported in FFmpeg; it is the Logitech H.264 "internal"
streams in the key and delta frames (APP0 field) that are causing the trouble.
FFmpeg has no idea how to interpret them, and thus throws loads of warnings.
> Again, I don't know what VLC can do with this. :-/
I have a feeling that the VLC issue is different. As mentioned in my original
e-mail, it almost crashes (infinite UI-blocking loop) when trying to load these
bloody files. When I record a video with OBS (Open Broadcaster Software) using
the separate x264 encoding module, the video is obviously no longer MJPEG, and
VLC plays it fine. (Nonetheless, I would like to play native Logi MJPEG files.)
VLC is supposed to have an MJPEG-demultiplexing module [1, 2], and it seems to
be able to find it:
$ vlc --list | grep mjpeg
VLC media player 3.0.10 Vetinari (revision 3.0.10-0-g7f145afa84)
mjpeg M-JPEG camera demuxer
... But when I specify `--demux=mjpeg` on the command-line, it cannot be found:
$ vlc --demux=mjpeg mjpeg-test.mp4
main demux debug: looking for demux module matching "mjpeg": 46
candidates
main demux debug: no demux modules matched
[1] https://git.videolan.org/?p=vlc.git;a=blob;f=modules/demux/mjpeg.c#l49
[2] https://wiki.videolan.org/Documentation:Modules/mjpeg/#Demux
--
Ashley Dixon
suugaku.co.uk
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