> From [EMAIL PROTECTED]  Thu Sep  4 10:45:39 2003
> 
> > Based on the values I used to encode the mpeg2 files I've been
> > testing with "dvdview", it seems that the reported value of bitrate
> > is always 2.5 times the value I encoded at.  So if I set the
> > max bitrate at 10000, the reported value is 25000.  Which means,
> > I can easily figure out the actual value, but I'm still very
> > curious as to why the number is multiplied.
> Usually the bitrate reported by a mpegplayer is the maximal bitrate. Set
> somewere in the header. 

Which now leaves me with two questions:

1) why is the value 2.5 times what I set as the maximum rate?

2) why would the bitrate (and other values which really didn't
        change much) either a) be stored in the mpeg-2 file
        every 15 frames or so, or b) why would dvdview printout
        the SequenceHeader every fifteen frames, if it was only
        stored at the beginning of the mpeg-2 file?

> > And, I'd also like to know what some of the other values reported
> > with each SequenceHeader are:
> >         VBV buf.size -- generally reported as 112, except from
> >                 an mpeg-1 trailer I downloaded, which reported 3.
> >         aspect code -- always seems to be 2 for mpeg2enc output
> >                 (including an SVCD), and 1 for an mpeg-1 file
> >                 I have.
> >         constrained -- no idea.  It was always false except the
> >                 mpeg-1 trailer.
> >         profile -- don't know, but possible values are: Simple,
> >                 Main, SNR, Spatial and High.
> >         level -- don't know, but possible values are: Low, Main,
> >                 High and High1440.
> I guess that the aspect code is directly compareabel with the mpeg2enc
> -a display aspect ratio codes. And 2 would mean 4:3. 
> The level/profile option look like it has something to do with HD-TV. 
> I have no idea about the other values. 

Okay, thanks for the help.
 
> Berni the Chaos of Woodquarter

        Bill

/*************************************************************************/
/* Bill Sherman  ([EMAIL PROTECTED])                                */
/* National Center for Supercomputing Applications                       */
/* University of Illinois at Urbana-Champaign                            */
/*     Og - "You want to do mankind a real service?  Tell funnier jokes" */
/*  Spinner - "but facts don't always reveal the truth"                  */
/*      Robin - "Yeah, but I always figure that's the writers' fault"    */
/*************************************************************************/



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