On Wed, 29 Dec 2004, Ray Cole wrote:
Hi!
> I've encoded several things since successfully compiling from CVS last week
> and it seems to me the quality has noticeably improved. I originally built
Do a cvs update and rebuild now - changes since last week might get
a (tiny) fraction more quality ;)
> from CVS wanting to try y4mdenoise, but it is just too slow for me to use.
It does want a 2+GHz cpu doesn't it? I had one run on a 2GHz G5 that
went about 25 hours. Came out looking beautiful. I think things will
look better and run faster when I switch from the ADVC100 to the
-300 which can do some denoising on the signal as it's being digitized.
> However I do use y4mspatialfilter right before yuvdenoise, so my chain is
> {raw video} -> yuvscaler -> yuvcorrect -> y4mspatialfilter -> yuvycsnoise ->
> yuvdenoise -> mpeg2enc. ..short chain :-)
Hmmm, the 'yuvycsnoise' filter could probably be dropped - even when I
was using a Bt878 card that filter didn't seem to make any difference
(for better or for worse).
If you're capturing at full frame square pixel (which for a Bt878 is
640x480) then you are scaling/resampling to 704x480 and not 720x480
I hope. If the latter then the aspect ratio is being distorted about 2%.
Full frame broadcast TV (and VHS tapes, etc) in the US are 704x480 with
10:11 pixels. This, as arithmetic will show is a 4/3 image equivalent
to 640x480 with 1:1 pixels.
> Anyway, it appears to me the quality is a little better than before (ie - last
> official release). Edges seem to be very crisp now. I'm not sure if that is
Glad to hear that the last year of development hasn't been a complete
waste of time :-) :-)
> from improvements in yuvdenoise, the addition of y4mspatialfilter, improvement
> to mpeg2enc, or some combination :-)
"All of the above" <grin>. y4mspatialfilter didn't exist in the
last "official release" as I recall though.
> y4mspatialfilter's defaults caused the image to blur really bad, but I was
> able to tweak the parameters to it to get some good results. I get a slightly
Hmmm - interesting. For capturing from VHS tapes the defaults are
fairy moderate (-L 4,0.75,4,0.75 -C 4,0.6,4,0.6). For laser discs I
bumped up the 0.75 to 0.8. The -C (chroma) values are definitely
over-conservative (0.5 would probably have been better) since VHS
has only about 1/2 the chroma bandwidth that broadcast TV has.
> lower bitrate using y4mspatialfilter, but keep it before yuvdenoise because
> if I place it after yuvdenoise it tends to blur a little. Seems like
> yuvdenoise runs faster than it used to as well, though I've not done any
It does. Stefan and others put effort into speeding it up - nice to
hear that the improvements are noticeable.
Cheers,
Steven Schultz
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