[FFmpeg-user] Help needed to work around incorrect DTS when capturing H264 from a Logitech C920

Carl Eugen Hoyos cehoyos at ag.or.at
Mon Dec 15 18:49:22 CET 2014

Peter Rabbitson <rabbit+list <at> rabbit.us> writes:

> ffmpeg -r 30 -f v4l2 -s 1920x1080 -vcodec h264 

I believe -r 30 does not do what you think it does 
and it may be the reason for the issues you see.
Is there a problem if you remove it?

> -i /dev/v4l/by-id/*HD_Pro_Webcam_C920* \
>    -c:v copy -f matroska -

Since matroska is really the wrong format for this 
task: Does it make a difference if you write a raw 
stream? The advantage is that if the issue is still 
reproducible, you can use "-r 30" in a second run 
to smooth the timestamps.

Carl Eugen

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