Re: MPEG-2 Problems

Erik Slagter wrote:
> On Thu, 2006-02-23 at 17:16 -0600, Brian Brice wrote:
> > Greetings, I've been testing some code for outputting MPEG-2 videos
> >  and I've been having some problems.  First I checked what was 
> > wrong with my code, then tried to verify things with the main 
> > ffmpeg program.  It seems the program does the same.  The problem 
> > that I'm getting is that the MPEG-2 video format that ffmpeg 
> > outputs doesn't seem to be correct.  In all of the players I've 
> > tested with, the duration time of the video is WAY off (such as 
> > really huge or even a negative number), and others can't even play
> >  it.  Here's a sample invocation of ffmpeg that I've used:
> >
> > ffmpeg -i ffmpeg-sample.mpg test.m2v
> >
> > The "ffmpeg-sample.mpg" is the file produced by the output_example 
> > program, but the problem persists with any kind of input video.  I 
> > did try converting the file with:
> >
> > ffmpeg -i ffmpeg-sample.mpg -vcodec mpeg2video test.mpg
> >
> > This used the mpeg output format and mpeg2video codec, which the 
> > regular mpeg output format seems to be for MPEG-1.
> >
> > Anyone else experience this?  Any solutions?  Is the mpeg2video 
> > output format "complete" or what?  Thanks in advance.  :-)
>
> You might want to supply the CONTAINER, which in this case should be 
> vob (mpeg2 program stream). If you don't, mpeg1 systems stream will 
> be used.

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

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.

--
Brian Brice
In order to know recursion, you must first know recursion...