[FFmpeg-user] Question about v4l2 controls and ffmpeg, also dts muxer problems

Carl Eugen Hoyos cehoyos at ag.or.at
Sat May 5 09:09:24 CEST 2012

Goetz Dapp <goetz.dapp <at> googlemail.com> writes:

> ffmpeg -f video4linux2 -framerate 30 -video_size hd720 -input_format
> mjpeg -fflags igndts -an -i /dev/video0 -c:v copy -an /HDD2/test1.mjpeg

> I am curious though if there is any way of controlling the v4l2 control
> ids through ffmpeg, i.e. things like V4L2_CID_WHITE_BALANCE_TEMPERATURE,

No, but I believe it should be straight-forward to implement, see 
v4l2_set_parameters() and options[] in libavdevice/v4l2.c

> The autofocus particularly kicks in during recording and messes things up.

> I also have another problem, namely that I am getting tons of errors
> "/Application provided invalid, non monotonically //increasing dts to muxer"

Complete, uncut console output missing.

> If I tell it to save it as an .avi file it crashes immediately

Crashes are important, please provide the missing information 
as explained on http://ffmpeg.org/bugreports.html

> with the mjpeg it seems to record relatively OK. Is there a
> way of solving this?

> Or, at the least, to turn off the error messages?

-loglevel xx ?

Carl Eugen

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