[MEncoder-users] Telecine and B frames for DVD

[Rich Felker]

On Thu, Feb 14, 2008 at 07:07:56PM -0200, Walter R. G. Hachmann wrote:
> On Tue, 12 Feb 2008 21:19:21 -0500, Rich Felker wrote:
> 
> 
> 
> > > Do we have a mpeg muxer bug here???
> >   
> 
> > Probably.. Can you try with max_b_frames=1 and any other variants you
> > can think of?
> > 
> > Rich
> 
> 
> Hi, Rich
> 
> I repeated the tests with vmax_b_frames=1, 2, 3, 4, 5 and 6. The 
> interesting thing is that the problem arises with 2, 4 and 5 B frames, 
> but not with 1, 3 and 6. With 6, I start to have additional problems 
> when muxing (mplex error messages). I also tested it again with 
> vmax_b_frames=2 and mbd=2, but the same problem happened again.

OK, I suspect the mpeg muxer was only tested with 1 B frame...
Hopefully nico or someone will pick up on this report and fix the
issue but for now I think your best bet is to stick to 1. IIRC this is
what most commercial discs do anyway and it might even be part of the
(not-so-strictly-followed) DVD spec. Most of the old PSNR tests done
with mencoder also showed the best results with only 1 B-frame, I
think.

Rich