On Fri, 31 Dec 2004, Adam Gautier wrote:
> > Ok, "generic MPEG-1" at a 1Mb/s rate. That does seem a bit low
> > for 800x600.
>
> Should I raise it?
Well, consider that "VCD" resolution (352x240) typically uses about
1100 I'd think that 800x600 would need a few more bits to look good :)
> > mplex -f 0 -r 1200 -o 3mintest.mpg final.m1v final.mp3
> >
> I tried both 1200 and 1300 no luck...
>
> The bit rate for the mp3 is interesting becuase I thought it was rendered
> as 256(Kbs), Thoughts?
Not really ;)
How was the MP3 file created (if you already mentioned that then I
forgot ;)). While MPEG-1 video and "MP3" audio is an unusual
combination it should work for playback on a computer.
The other very interesting thing which I didn't catch at first is the
"Vbv buffer size":
> $ mplex -f 0 -r 1300 -o 3mintest.mpg final.m1v final.mp3
> INFO: [mplex] mplex version 1.6.2 (2.2.3 $Date: 2004/01/13 20:45:26 $)
> INFO: [mplex] File final.m1v looks like an MPEG Video stream.
> INFO: [mplex] File final.mp3 looks like an MPEG Audio stream.
> INFO: [mplex] Found 1 audio streams and 1 video streams
> INFO: [mplex] Selecting generic MPEG1 output profile
> INFO: [mplex] Multiplexing video program stream!
> INFO: [mplex] Scanning for header info: Video stream e0 (final.m1v)
> INFO: [mplex] VIDEO STREAM: e0
> INFO: [mplex] Frame width : 800
> INFO: [mplex] Frame height : 600
> INFO: [mplex] Aspect ratio : 1:0.6735
> INFO: [mplex] Picture rate : b reserved
> INFO: [mplex] Bit rate : 1000000 bits/sec
> INFO: [mplex] Vbv buffer size : 1222656 bytes
My goodness that's HUGE! Even HDTV (~14Mb/s) only needs 488KB but
here we have a supposedly 1Mb/s stream that mplex says needs over
a megabyte!
Hmmm - the other very interesting thing is the "Picture rate". What
kind of frame rate is "b reserved"?
mplex is getting some weird (probably very high) frame rate which is
confusing/breaking the other calculations that go into multiplexing
a stream.
It's beginning to look like the video stream is bogus somehow.
I have no idea what cinelerra (sp) is doing for the encoding - but it
appears to be causing a really strange stream to be output.
Steven Schultz
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