[FFmpeg-devel] libavformat and video4linux2 acquire problems

[Levente Novák]

On Tue, 2007-05-08 at 16:14 +0200, Sandro Cavazzoni wrote:
> Hi Luca,
> 
> On 08/mag/07, at 13:28, Luca Abeni wrote:
> 
> > Hi Sandro,
> >
> > Sandro Cavazzoni wrote:
> >> Hi to all,
> >> In this days i started to develop an application based on libavformat
> >> and libavcodec, but i run into problems.
> >> Is this the right mailing list about development with libavformat and
> >> libavcodec?
> > If you found a bug, I think it is ;-)
> >
> >> i'm trying to acquire a video from an acquisition board with a FUSION
> >> 878A chip.
> >>
> >> I open the device with the next code:
> >>
> >> 	AVFormatParameters	formatParameters;
> >> 	
> >> 	formatParameters.device = inputDevice; 			// /dev/video0
> >> 	formatParameters.channel = 0;						// It's video composite input on
> >> my board
> >> 	formatParameters.standard = "pal";
> >> 	formatParameters.width = 768;						// 768 - 384
> > This looks a strange width. Most of the capture cards I have tried  
> > work
> > well with width=720, but may behave strangely with width=768...
> 
> Hmm... the original windows software for this board work with 768x576
> 

I had the exact same problem last week. The v4l2 driver resetted the
card from 720x576 to 640x576, while it used to work OK until at least
april this year. It seems it tries to impose an NTSC horizontal
resolution even for PAL content. I think it is libavcodec at fault, as I
don't remember having recompiled the kernel or bttv inbetween.

Levente

PS: I did not try grabbing with Ffmpeg or MEncoder since then.