[MEncoder-users] cat /dev/video0 | mencoder - ...

[Reimar Döffinger]

On Tue, Jul 27, 2010 at 08:39:27AM -0400, Bob Tennent wrote:
>  >|You could try -tv noaudio (or read the manual to find the correct
>  >|incantation to
>  >|record audio, for me - using btaudio - it's -tv alsa=1:adevice=hw.2).
> 
>   -tv noaudio
> 
> produces 
> 
>   v4l2: ioctl request buffers failed: Invalid argument
>   v4l2: 0 frames successfully processed, 0 frames dropped.
>   ============ Sorry, this file format is not recognized/supported =============
>   === If this file is an AVI, ASF or MPEG stream, please contact the author! ===
>   Cannot open demuxer.
> 
> I don't understand why this is so complicated.  
> 
>    cat /dev/video0 > file.mpg
> 
> produces a perfectly good mpg that mencoder can process, even while it's
> being created. Why isn't a simple buffer or pipe sufficient?  

What's the problem with
mplayer /dev/video0
?
Either way you'll probably want a large -cache value to avoid some issues.