[Ffmpeg-devel] Problem using ffmpeg with v4l

Flavio Pimentel Duarte flaviop
Mon Jan 9 19:37:49 CET 2006

On Sun, 8 Jan 2006, Erik Slagter wrote:

> On Fri, 2006-01-06 at 17:08 -0200, Flavio Pimentel Duarte wrote:
> > We've track down the problem to the grab.c in libavformat directory. It 
> > seems that the call in line 138
> > ret = ioctl(video_fd,VIDIOCGMBUF,&s->gb_buffers);
> > is failing. Changing it to a simple "ret = -1" make everything work fine.
> >  	I still wondering if I am doing something wrong or if it is really 
> > a bug. Anyway it would be very good if this issue was fixed.
> Probably your webcam does not support the import format ffmpeg expects.
	Now I understand how v4l works. I read the V4L documentation I 
realized that ffmpeg was not setting things when mmap is used. I will send 
a patch in my next email.


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