[MPlayer-users] MJPEG Streams on MacOS, Linux, Windows

[Reimar Döffinger]

On Mon, May 13, 2019 at 06:17:28PM -0400, Kevan Hashemi wrote:
> ffmpeg -i Mouse.mp4 -f mpeg tcp://127.0.0.1:8888?listen
[...]
> kevan$ ./mplayer -cache 1000 ffmpeg://tcp://10.0.0.235:2222
> MPlayer SVN-r38017-4.2.1 (C) 2000-2018 MPlayer Team
> Playing ffmpeg://tcp://10.0.0.235:2222.
> libavformat version 58.3.100 (internal)
> Cache fill: 19.20% (196608 bytes)
> Cannot seek backward in linear streams!
> Cannot seek backward in linear streams!
> libavformat file format detected.
> Cannot seek backward in linear streams!
> [mjpeg @ 0x1043d7630]Found EOI before any SOF, ignoring
> [lavf] stream 0: video (mjpeg), -vid 0
> VIDEO:  [MJPG]  820x616  0bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> libavcodec version 58.9.100 (internal)
> Selected video codec: [ffmjpeg] vfm: ffmpeg (FFmpeg MJPEG)
> ==========================================================================

The "found EOI before SOF" hints at issues already.
But the "-f mpeg" to FFmpeg and MJPEG codec...
Are you putting MJPEG into a MPEG container?
Or is it a typo and it's raw MJPEG?
Either is quite a horrible format.
As far as I know, basically all MPlayer versions will
fail to properly auto-detect that and hang randomly,
and what you are seeing is probably some versions handling
it better than others.
I would most strongly recommend to pick some other format
(e.g. mkv, nut or such), but if you have to use this,
try to help MPlayer out a bit by e.g. specifying
-demuxer lavf and maybe even -lavdopts format=mpeg
(I don't think that is quite the right format name
to use, but something like that)