On Mon, 8 Dec 2003 [EMAIL PROTECTED] wrote:
> I am trying to encode one of my commercial DVDs onto a XVCD using dvd::rip.
>
> The DVD title is 132 minutes. Using the following settings for mpeg2enc
Whew - that's a lot to try and get any quality from and still
fit on a CD-R.
Are you using the standard VCD frame size (352x240 or 352x288)?
> -K kvcd -q 8 -N 1.0 -b 2000
Leave out the -N if you're using -K kvcd. The kvcd tables already
have the high frequencies "rolled off" (not the right term actually -
sampled to less detail might be better) and -N amplifies that effect.
> Most of it is good, but some sequences are blocky and there are many
> artifacts i.e. halos around people, letters (subtitles rendered with
> transcode's extsub), etc.
How did you scale the DVD data to the VCD size? With y4mscaler or
some other method? Depending how the scaling is done can cause
increased halo/ghosting. If you're using y4mscaler 0.5.0 then
"-S option=sinc8lan" will probably give the highest quality, if you're
using y4mscaler 0.6.1 (which was released this weekend) then that
becomes "-S option=sinc:8" (unless I forgot the new syntax already ;)).
-q 8 will produce more blockiness than -q 6.
> If I bump -q down to -q 6, I get mplex buffer underruns. If I take out
> the -K kvcd, the filesize shoots up to twice.
Then specify the correct bitrate to mplex. When you're creating
nonstandard (XVCD/XSVCD/genericMPEG) formats you have to give mplex
a better idea of the maximum bitrate. Either give an arbitrarily
large value (knowing it will never be approached) or add the video
rate and audio rate and multiply by 1.03. "-r 3000" should work
fine. Or take the 2000 you specified to mpeg2enc, add in 224 for
the audio and then a couple percent for overhead - 2224*1.03 = ~2300
Oh, you'll probably also need '-V' to mplex to tell it that the
bitrate is variable rather than constant (be nice if mplex could
figure that out for itself ;)).
Depending how big the image ends up being you might try '-K tmpgenc'
to use the TMPGEnc tables - the bitrate won't be quite as low as
with kvcd but the quality will be better (hopefully).
> Any magic incantations to mpeg2enc to get the optimal quality at lowest filesize? Or
> is it pretty much trial and error?
Yes.
;)
If you're using the cvs version of mpeg2enc you can also try adding
"-E -10" to the options - for clean source (such as from a DVD)
that option can be quite valuable. Might save enough bits that you
could use a lower -q (and odd values of -q are allowed - you could
try -q 7 if desired).
Good Luck.
Steven Schultz
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