Re: MPEG-2 Problems

Hi

On Fri, Feb 24, 2006 at 10:37:51PM +0100, Erik Slagter wrote:
> On Fri, 2006-02-24 at 15:31 -0600, Brian Brice wrote:
> 
> > This works great and looks as I expected.  Now this leads to another
> > question.  What about using the mpeg2video output format?
> > 
> >      ffmpeg -i sample.mpg -f mpeg2video -vcodec mpeg2video test.m2v
> 
> I don't know the subtleties between "vob" and "mpeg2video".

MPEG-PS vs. MPEG-ES 


> 
> > When specifying an output file with the m2v extension, it guesses the
> > mpeg2video output format and mpeg2video codec, but something in the
> > output seems "off".  I downloaded a few m2v videos to test the players I
> > was using to see if they showed way off durations and that was not the
> > case.  Here are some durations reported with the 5 second clip, ffmpeg
> > MPEG2 file:
> > 
> >      Windows Media Player: 40865:59:01
> >      DivX Player: -300212:-29:-15
> >      Real Player: 18:03:13:24
> > 
> > In other clips I found, all 3 players showed the same duration for
> > these.  Viewing the m2v files in a hex editor showed they all start with
> > the video sequence header (0x000001b3) instead of a program stream pack
> > header.
> 
> That I cannot comment upon, I do know that mpeg ps does not store the
> video length in any way, so I guess it's rather pointless for an
> application to show it, or it has to go through the complete file to
> count all frames.

WMP & co. assume MPEG* to be CBR if thats false they mess up to various
amounts ...
try a true CBR file (maxrate=minrate and some non zero bufsize) i guess
duration should be correc then

[...]

-- 
Michael