[MPlayer-users] mencoder, x264, vorbis, matroska - bad a/v sync problems

[matthew.garman at gmail.com]

[ I reordered your remarks slightly ]
On Wed, Feb 14, 2007 at 12:08:22PM -0800, RC wrote:
> > What's wrong with the framerate?  That number is 24000/1001
> > rounded...
> 
> It shouldn't be the cause of your problem, but it might result in
> a very slow gradual desync.

Hmm, I'm not sure if MP4Box can take a "fractional" representation
(24000/1001) like mencoder or not.  All the examples on the web show
it being used with a rounded float value (not that that makes it
right ;)

I don't think that's the problem, though, as my sync problems are
pretty abrupt.

> > I've just assumed so far that bframes=4 is best for quality with
> > x264,
> 
> It probably is.  But b-frames are often a cause of a/v sync
> issues.
> 
> > Is the only way to test this to try with other players, such as
> > Xine and (shudder) Windows Media Player?
> 
> To find out for sure, yes.  Though some option can often fix sync
> issues. You could try MPlayer with -mc 0/10/0.0001, and -autosync
> 1/30.

I still have yet to try those suggestions, but I was wondering if
you (or anyone) happen to have a script (or equivalent) you'd be
willing to share that you use for encoding and muxing x264+vorbis
into a matroska or ogm or mp4?

I don't mean to sound sarcastic or cynical, but I'd like to take
someone's known-to-work x264+vorbis process and test it on my
source.  Maybe my source material is really just *that bad*?

Although, FWIW, I've had no sync problems with -of avi -oac copy
-ovc x264 and just leaving it at that (i.e. use only mencoder).[1]
<shrug>


Thanks again,
Matt



[1] I should probably leave well-enough alone but (1) I didn't want
    to be creating nonstandard (>2GB) AVIs and (2) started to
    realize how much space I was wasting with -oac copy (when oggenc
    -q7 or even flac can save a tremendous amount of space at little
    to no quality loss).

    Just for kicks, I'm now trying doing everything in mencoder, but
    using -of faac instead of -of copy.  I expect this to work,
    although I'd rather not use AAC (would rather use one of the
    "free" formats).