[MEncoder-users] Problem encoding raw video output of mencoder

[R.L. Horn]

On Tue, 20 May 2008, Bram wrote:

> Taking a good look at the patch, it seems that this is the culprit:

Yep, that's it, I believe.

> Not being an expert on raw video formats, I figured this header was used
> by mencoder to determine the raw video properties, but it appears not to
> be the case (so it really expects just raw data).

That's correct.

>> But why patch mencoder to accomplish the above anyway?

> I can't get at just the audiostream without the patch. Is it possible?

   mplayer -vc null -vo null -ao pcm:fast:nowaveheader:file=fifo

Unfortunately, -vc null only appears to work with MPEG PS and avi at the 
moment, which may carry over to mencoder (I know mencoder doesn't cope 
well with Matroska input, for example).

A better approach all around might be to use ffmpeg.  To extract and 
decode an audio stream, you could use:

   ffmpeg -i VIDEO_FILE -ac CHANNELS -f s16le - > fifo