On Tue, 24 Aug 2004, Selva Nair wrote:
> I do not understand why multiplex rate should affect playback, that's why
> I left it for your experimentaion instead of spamming the list
> with my half-baked conclusions ;)
It doesn't - at least I've never had it. Lowering the bitrate
of the video will produce something that will make your eyes hurt
but won't cause audio stuttering.
> By the way, later (> 1.6.1 release?) versions of mplex can be forced to
> use a lower bitrate than the default of 10.08Mbps with -f 8. That may be
> another way to multiplex low bit-rate streams.
> I really do not know whether its important to keep the mplex rate not too
> much higher than the actual video+audio rate.
Doesn't make any difference. All you need to be is over
the point at which mplex gives underrun errors. 1 bit/sec over is
all that's needed ;) As long as the final total bitrate's less
than 10.08 (and this includes any peaks/spikes - not just the
"Average"!) you could put anything in the MPEG header. I've seen
DVDs flagged as 9800kbit/sec for the video but on closer examination
were closer to 6500 - the multiplexing just stuffed in the largest
permitted DVD value.
> Also is there a practical lower limit for dvd bitrate?
That's between you and your eyeballs ;)
Much depends on the source and the amount of filtering done of course.
Since DVDs are allowed to use the 352x480 (or 352x576) resolution
you can give up some spatial resolution but then use a higher bitrate
to avoid blockiness.
For fullframe size with good material clean material and a modest
amount of filtering you can get by with ~5000 kbits/s at a reasonable
quality. At the 1/2 D1 resolution a bitreate closer to 4000 or less
will produce quite a long playing time at a very acceptable quality.
> Even if the issue was with the mplex rate, that much fine tuning should
> not be required. I never had any audio problem with mpeg2enc/mplex
Nor have I. I have had audio playback issues with mplayer due to
broken/miscompiled audio decoders but that wasn't mplex/mp2enc/mpeg2enc
related.
> although I haven't used used extreme values of bit rates. Possibly
> something is wrong with xine too: if you run xine with --verbose you may
> get some messages on audio drifts, if any.
That's a good idea. If xine is having to stop/start the audio in an
attempt to maintain a/v sync that would could cause the audio problems.
Cheers,
Steven Schultz
-------------------------------------------------------
SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285
_______________________________________________
Mjpeg-users mailing list
[EMAIL PROTECTED]
https://lists.sourceforge.net/lists/listinfo/mjpeg-users
