[MEncoder-users] Howto fix audio delay

[Oded Shimon]

On Mon, Jul 04, 2005 at 10:07:58AM -0400, The Wanderer wrote:
> According to the man page, that doesn't work with negative delay values,
> meaning that while you can use it to correct for audio which is played
> too early it won't help with audio which is played too late.
> 
> I don't personally know of any reason why it would not be theoretically
> possible to simply pad the beginning of either the audio stream (in the
> case of "audio played too early") or the video stream (in the case of
> "audio played too late") with 'blank' frames during the encoding stage,
> such that in the former case no sound would be played and in the latter
> case no video would be output, to correct for the mis-synchronization,
> but since no one has attempted to implement such a seemingly obvious
> thing I suppose there might be a technical obstacle I'm not aware of.

Yes, the obstacle is -oac copy and -ovc copy.
Since all frames (both video and audio frames) are compressed, you can't 
just pad them with "nothing", you have to pad them with a legally 
compressed "silence" or "blackness". this is impossible if you can't fake 
the original encoder...

- ods15