[Ffmpeg-devel] Problem using ffmpeg with v4l

Flavio Pimentel Duarte flaviop
Fri Jan 6 20:08:51 CET 2006

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.


PS: I forgot to mention that all my tests were performed using cvs 

On Fri, 6 Jan 2006, Flavio Pimentel Duarte wrote:

> I am having problems to capture from USB webcam model Creative Notebook, but 
> I think this problem is not restricted to this model. Capturing movies using 
> this webcam generates a very dark movie. I've made several tests using both 
> mplayer and motion programs and during the tests I noticed that starting 
> mplayer using the webcam as source prior to use ffmpeg sometimes solves this 
> problem. This particular behavior made me think it should be an 
> initialization problem. The program motion also generates dark pictures with 
> the default configuration, but the option auto_brightness seems to fix the 
> problem.
>   Does anyone have suggestions to deal with this problem ?
> Flavio
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