[MPlayer-dev-eng] [PATCH] new mpeg muxer

[Joey Parrish]

On Thu, Feb 24, 2005 at 12:57:38AM -0500, D Richard Felker III wrote:
> On Wed, Feb 23, 2005 at 11:00:13PM -0600, Joey Parrish wrote:
> > > - i seem to occasionally get weird out-of-order glitched frames during
> > >   really high motion scenes. is this due to buggy reordering of some
> > >   sort in the muxer, failure to enforce closed gops, or something
> > >   else? i think i can extract small samples that exhibit the problem
> > >   if you want to see one.
> > 
> > I've noticed this in some of my home-made DVDs.  I dug through the
> > source MPEGs, and the problem lies there.  The source is interlaced NTSC
> > MPEG2 from a Tivo, and there are (rarely, but noticably) missing fields.
> > Any correct way to deal with that other than a blurring deinterlace
> > filter?  I've never really liked the way those look.
> 
> Missing fields?? What do you mean?
> This is a different problem from what I was experiencing.

According to an MPEG parser in my DVD authoring app, the frames are:
  X+0. top
  X+1. bottom
  X+2. top
  X+3. top
  X+4. bottom

within the same GOP.  I have no clue what this is about, I'm only now
learning about MPEG internals of out neccessity over the past few
months.

> > I'm having compilance issues with dvd format, too.  I specified
> > format=dvd under mpegopts, but my dvd authoring app doesn't like the
> > streams.  Doesn't say why, mind you... :(
> 
> You also have to use the right parameters to the mpeg video encoder..

Yes, keyint=15 fixed that.  Thanks.

> > Also, mencoder wants to screw up audio sync pretty badly from my Tivo
> > recordings.  After an hour, I'm a whole scene off.  The story is:
> > 
> > -ovc lavc -lavcopts vcodec=mpeg2
> >   complains that "2997 / 100" is not a valid framerate for mpeg.
> >   which is stupid, because the source file is an mpeg.  it's upset
> >   over rounding and conversion errors introduced by the mplayer core
> >   itself.  (somewhere)  I'm not able to fix this off-hand.
> 
> Try -ofps 30000/1001
> 
> > -ovc lavc -lavcopts vcodec=mpeg2 -ofps 30000/1001
> >   encodes, but with massive audio sync problems.
> [...]
> > And I still can't help but feel like I'm missing something very
> > fundamental and important.  Am I just mad, or is this really hard?
> 
> OK, you did. Also use harddup as the last filter in your filter chain.
> If you're not using it and seeing any "duplicate frame" messages
> whatsoever, a/v sync is being horribly ruined in your output file.

I've been trying with/without harddup, with/without noskip, with/without
audio re-encoding, etc.  I still can't get any better than what I've
listed above.  Noticable (less than 1 sec) desync after 30-60 minutes.

--Joey

-- 
"I can read it better than you can read it with your eyes closed." --Gu