[FFmpeg-user] V4L2 recording results in invalid data & buffer still owned errors.

[YoureSquidNow]

I hope it is okay to dig up a 9 months old thread. Also, this is my first
time on such a mailing list, so please bear with me.

I too have a problem with getting the Magewell XI100DUSB-HDMI capture device
to communicate with ffmpeg properly. I ran into the same 'The v4l2 frame is
0 bytes' issue as described above. My goal is to stream Wii U game footage
to twitch.

Now, while I have zero in-depth knowledge of ffmpeg, it struck me that
Magewell advertises that the dongle provides the resolution/fps you want it
to. While I have no idea how this works, this might explain this odd
behavior. Just before the dongle can adjust, ffmpeg already gives up on it.

Someone stated that it works once after rebooting - I found out that
disconnecting the dongle does the same. In my case, the very first try then
yields a 82944 bytes frame - 720x576 (which might be what the Wii U streams,
but I doubt it).
In other words, this command line sucessfully records video right after
plugging the dongle in:
ffmpeg -f v4l2 -framerate 60 -s 720x576 -i /dev/video0 output.mkv

What I will try now is to reset the USB connection through command line and
work with this resolution.

I hope however that someone with in-depth knowledge has an idea on how to
make ffmpeg 'give the dongle a chance' before aborting.

Thank you!




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