Hi!
Over the last couple days I've made the best looking DVDs yet (one
in particular I'm quite proud of - amazingly good looking) and
thought others might find the information useful as a starting point
for experimentation. Average bitrate was right on target at around
5500Kb/s or so - fitting a 99minute movie on a DVD without too much
space left available.
The captures were from a laserdisc player via a Canopus ADVC-100
(of course :)).
Couple variables I set at the top of the script are the filename
and "-q" value for the encoder:
N=ltad
Q=4
then "smil2yuv -i 2" and "y4mscaler -O chromass=420_MPEG2" are used
to convert the raw DV data into YUV4MPEG2 420:
smil2yuv -i 2 -a $N.wav ../$N.smil | \
y4mscaler -O sar=src -O chromass=420_MPEG2 | \
I always seem to need a small shift (usually 4 but occasionally 6
pixels to the right) to center the data within the 720 sized frame:
y4mshift -n 4 | \
moderate yuvdenoise'ing is then done and the left+right borders (where
the noise/junk pixels show up) are turned to black. I determine the
size of the black area by taking a frame (smil2yuv -f 1 -o 3000 |
y4mtoppm -L > /tmp/foo) and looking at it with a 16x zoom via the GIMP.
yuvdenoise -S 0 -r 24 -t 6 -l 2 -b 12,0,696,480 | \
next I use the median filter BUT only on the 'chroma' and not the
'luma' portion - this avoids the sometimes excessive softening/blurring
that has been mentioned but does clean up the colors (and dark scenes
improve a bit), lot faster too since it's not doing as much work.
yuvmedianfilter -t 0 -T 2 | \
lastly I want the center 704 pixels (704x480 and 704x576 are valid
DVD resolutions) so as to not have large black borders show up when the
movie is played - 'y4mscaler' to the rescue again, it automagically
grabs the center 704 pixels with:
y4mscaler -v 0 -O size=704x480 -O sar=src | \
then it's off to the encoder with a 'bfr' stage in front to help
keep him busy:
bfr -b 10m | \
mpeg2enc -N -M 2 -f 8 -q $Q -4 2 -2 1 -o $N.m2v
The -q value at 4 is low, for some material I'll drop back to 5 or 6
but so far 4 has worked out quite well - the highest bitrate I've
seen over the last couple DVDs is about 6500Kb/s (89 minute movie fit
with about 100MB left :)).
The entire pipeline looks like this:
smil2yuv -i 2 -a $N.wav ../$N.smil | \
y4mscaler -O sar=src -O chromass=420_MPEG2 | \
y4mshift -n 4 | \
yuvdenoise -S 0 -r 24 -t 6 -l 2 -b 12,0,696,480 | \
yuvmedianfilter -t 0 -T 2 | \
y4mscaler -v 0 -O size=704x480 -O sar=src | \
bfr -b 10m | \
mpeg2enc -N -M 2 -f 8 -q $Q -4 2 -2 1 -o $N.m2v
The toolame and mplex, and dvd authoring commands are left as a exercise
for the reader :)
Oh, if you're after extended play time you can change the sequence to:
smil2yuv -i 2 -a $N.wav ../$N.smil | \
y4mscaler -v 0 -O sar=src -O chromass=420_MPEG2 | \
y4mshift -n 4 | \
yuvdenoise -S 0 -r 24 -t 6 -l 2 -b 12,0,696,480 | \
y4mscaler -v 0 -O size=704x480 -O sar=src | \
yuvmedianfilter -t 0 -T 2 | \
y4mscaler -v 0 -O size=352x480 -S option=cubicB | \
bfr -b 10m | \
mpeg2enc -M 2 -f 8 -q $Q -4 2 -2 1 -o $N.m2v
since 352x480 and 352x576 are also legal DVD resolutions. The extra
y4mscaler call is not because I like the program so much (<g>) but
rather wanted yuvmedianfilter to work on the 704 sized frames (instead
of the 720 from before scaling or the 352 from after scaling). To me
the quality looks good (even on a regular TV). Definitely suitable
for casual viewing and much more convenient than a 2 DVD set (cheaper
too especially at what dvd+r media costs).
And that's it - the optimal pipeline that I've crafted up to this
point. The results are excellent (but then I have an old set of
glasses I'm wearing :)).
Cheers,
Steven Schultz
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