[vlc-devel] Re: V4L Stalling on one Linux machine

James MacLean macleajb at ednet.ns.ca
Mon Apr 4 00:32:53 CEST 2005

James MacLean wrote:

> James MacLean wrote:
>> Hi Folks,
>> In modules/access/v4l/v4l.c in the function Demux I see
>>    if( p_sys->fd_audio < 0 || !( p_block = GrabAudio( p_demux ) ) )
>>    {
>>        /* Try grabbing video frame */
>>        p_es = p_sys->p_es_video;
>>        if( p_sys->fd_video > 0 ) p_block = GrabVideo( p_demux );
>>    } else {
>> GrabVideo() is never getting called from here. I expect it because I 
>> see GrabAudio is never returning 0.
>> If I stick a GrabVideo in the else, I get my video fine, but there is 
>> no audio....
>> Any suggestions as to what I am doing wrong :)?
>> thanks,
>> JES
> I must have some odd hardware interaction as I have not seen this 
> _yet_ on 2 other V4L machines. Is there some reason why the audio 
> would not be opened correctly in that it keeps returning data but that 
> data does not seem to be coming out as sound :)? Almost as if my igain 
> is at 0 which it is not. Mencoder continues to work as expected....
> To sumerize, if I add, in the above else, to do a GrabVideo, I can 
> finally see the video every time I start to stream. Problem remains, 
> that even doing this, I get no sound...
> As a sidebar, I was also able to freeze the video when it was started 
> with something like :
> vlc v4l:/dev/video0:channel=0:norm=ntsc:size=640x480
> just by repositioning the video window a few times.

Tried upgrading my ALSA drivers/libs to 1.0.9rc2. Seems to work more 
often, but not often enough :(.

Anyone shed some light on why the reading of the audio is not fast 
enough? Or why it is always returning data and not allowing and video to 
be catpured :) ?


This is the vlc-devel mailing-list, see http://www.videolan.org/vlc/
To unsubscribe, please read http://developers.videolan.org/lists.html

More information about the vlc-devel mailing list