[MPlayer-users] accurate VBR info, and more ... with midentify ?

[Juri Mianovich]

Hello,


--- Nico Sabbi <Nicola.Sabbi at poste.it> wrote:

> > When I run 'midentify' against a VBR clip (mpeg,
> or
> > h.264) I often see either an incorrect number, or
> a
> > "0" in the video bitrate.
> > 
> > Why is this ?
> > 
> > I would like to know three things about a
> particular
> > VBR video file:
> > 
> > - average bitrate
> > - peak bitrate
> > - low/minimum bitrate
> > 
> > I realize that midentify does not show me the
> average
> > (not sure what it is showing me, when it shows
> > something >0) and I know that I will need to,
> > essentially, play the entire clip through in order
> to
> > get the peak/minimum bitrates (and probably to get
> the
> > average as well).
> > 
> > Is there a command line that will tell my system
> to
> > play the clip as fast as the CPU will allow it,
> > without any actual video playback (like midentify)
> so
> > that I can get those three numbers as fast as
> possible
> > ?
> > 
> > Also, out of curiousity, when midentify shows me a
> VBR
> > birate of >0, what is it showing me, exactly ?
> > 
> > Finally, a lot of clips are giving me either
> > drastically wrong, or "0.00" for the:
> > 
> > ID_LENGTH
> > 
> > field in midentify ... is there any mplayer
> command
> > line that will show me an accurate length reading
> for
> > _all_ video clips?
> > 
> > thanks.
> > 
> 
> mencoder -ovc copy -oac copy -o /dev/null file.mpg


Thank you.  When I run this, I get this at the
beginning:

VIDEO:  MPEG2  1280x720  (aspect 3)  59.940 fps 
19000.0 kbps (2375.0 kbyte/s)

So the 19000.0 kbps is just the wrong number I get out
of midentify ... but I wonder, where does that 19000.0
kbps come from ?

When your command finishes, I get:

Video stream: 17164.721 kbit/s  (2145590 B/s)  size:
5733057996 bytes  2672.019 secs  160135 frames

So is the 17164.721 number the average bitrate ?

If so, how can I get the peak and minimum bitrate
numbers ?

Finally, why does midentify show:

ID_LENGTH=2573.38

but your command shows:

2672.019 secs

Why two different lengths ?

Thanks.


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