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

Georgi Chorbadzhiyski gf at unixsol.org
Tue Dec 16 11:25:27 CET 2014

On 12/16/2014 11:07 AM, Peter Rabbitson wrote:
> On 12/15/2014 06:49 PM, Carl Eugen Hoyos wrote:
>> 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 -

I've used Logitech C920 and noticed that the camera drops it's frame rate
without signaling it. So what happened was that I was seeing stuttering
in high resolutions and only when I dropped the camera resolution to 640x480
I was able to get steady input fps.

The lowering of frame rate occurred when the camera lens do not receive
enough light.

You are may be seeing similar problem.

Georgi Chorbadzhiyski | http://georgi.unixsol.org/ | http://github.com/gfto/

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