[MPlayer-users] "Too many video packets in the buffer" playing a merged file

[D Richard Felker III]

On Sun, Oct 03, 2004 at 01:47:03AM -0700, Loren Merritt wrote:
> On Sun, 3 Oct 2004, D Richard Felker III wrote:
> >On Sat, Oct 02, 2004 at 10:54:44PM +0100, Alessandro Di Rubbo wrote:
> >>P.S. To rich. You wrote: "NEVER EVER use -nosound unless you actually 
> >>intend for the final movie to have no sound!!!",
> >>but if I want to create a Matroska (mkvmerging
> >>a SINGLE .avi and an external .ogg) can I use -nosound option? As
> >>I've said already, I've notice no problem doing that.
> >
> >No, you cannot. It may work with some dvds, but a/v sync might be
> >slightly off, and with many it will be VERY wrong. Absolutely NEVER
> >use -nosound when encoding unless you intend for your FINAL movie to
> >have no sound (and thus no need for any sync). If you're going to
> >mkvmerge, you MUST keep audio with the file while processing it with
> >mencoder, due to the fact that mencoder sucks. Either use -oac copy or
> >-oac pcm with very low samplerate so it doesn't take up so much space
> >or cpu time.
> 
> What does mencoder's sucking have to do with that? If you retain all the 
> video frames and all the audio samples, how could the rip have any worse 
> synch than the original?

the original has timestamps mapping the two streams together.

> If you're saying that the video isn't quite 24000/1001 fps, or that the 
> audio isn't exactly 48000 Hz, then I could imagine a/v desynch.

no, they're both exact. the problem is that many dvds are _missing_
some audio frames, especially at chapter boundaries. or at least
that's what we seem to have found from experience...

the correct way to deal with this would be to insert silence in these
segments to "repair" the broken audio stream. but mencoder, in all its
stupidity, just drops some video frames here. better than causing
desync at least, though...

> But in practice, length of the soundtrack is always equal to the length 
> of the video to within one frame's duration, and I've never seen desynch 
> in the middle.

always? how many dvds have you checked? maybe this is true, and
mplayer's demuxer layer is just doing something idiotic that makes it
lose audio frames at some points. that's certainly not out of the
question. what tool did you use to extract the audio? did you extract
it as raw ac3, or pcm?

> Note: I don't use "mencoder -nosound", but rather I filter video through 
> Avisynth, which happens to discard the sound. Is that any different?

perhaps. i don't know how avisynth works.

rich