Hi -
On Sun, 13 Mar 2005, Matti Haveri wrote:
> I ran a series with -b 1875 and different -q values (8, 6, 4, 2, 1,
> and q omitted):
> The moving scenes were OK but dimly lit or quiet scenes were quite
> bad with -q 8. -q 1-2 and no q (=CBR) were the best in this regard. I
> found that -q 4 was the best compromise if I wanted to use VBR at all
You probably don't want to use VBR MPEG-1 - it's not 100% portable.
DVDSP3 rejected VBR MPEG-1 when I tried it, but CBR was accepted -
could be a bug in the DVD authoring software or it could that VBR
MPEG-1 is a nonstandard (for DVD) format.
> <http://www.sjoki.uta.fi/~shmhav/SVCD_on_a_Macintosh.html#Other_tools>
>
> Fiddling with -N high frequency filter might be useful, too.
That'll just soften the image (if the value is set too high - a value
value of 1.0 is about as high as I would go). But -N was added before
the extra quantization matrices were added. Today -N has been
effectively replaced with "-K" - you can use the builtin TMPGEnc
or KVCD tables or create your own and use "-K file=yourtables".
More important than tweaking -N is to denoise the data with y4mdenoise
before encoding.
If you're going for the best quality then you really have to take the
data into something like Final Cut Pro and perform color correction,
blacklevel adjustment and so on using the vectorscope and waveform
monitors (and a monitor calibrated to 6500K ;)). If you're interested
I can send a still frame from one tape that I processed - the
"with"/"without" correction difference is huge.
> Yes, Half-D1 is my low bitrate (~3750 kb/s) favorite, too, because it
> allows interlaced output. I dislike those jerky pans that progressive
Yes indeed! Tossing out half the temporal resolution makes some motion
scenes painful to watch.
> p.s. I recently ran a test with commercial MPEG encoder demos for Mac
> OS X and liked MainConcept MPEG Encoder the best. BitVice Lite was ...
> Mb/s based on content length). AFAIK Apple's Compressor (bundled with
> DVDSP and FCP) uses the same encoder engine as iDVD but it has more
> options for tweaking.
Compressor is "OK" but it doesn't have as many options for tweeking
as 'mpeg2enc' does. You can't enable DPME (DualPrimeMotionEstimation)
for example - not only that but Apple's MPEG-2 decoders seem allergic
to DPME ( I keep meaning to file a bug report but never have gotten
around to it). Hmmm, I also don't recall Compressor having a
counterpart to the "-D" option of 'mpeg2enc'.
Apple's encoders won't encode to MPEG-1 - "how do I create MPEG-1
content" is a FAQ on the Compressor/DVDSP/FCP forums ;)
Nice thing about mpeg2enc (which compares well in terms of visual
quality) is that it can be scripted into a bash script - you don't have
to be sitting at the console and set up a batch using a GUI only
tool.
I assume the commercial encoders come with denoising filters but I
have no idea how those compare with y4mdenoise and yuvdenoise. My
hunch is that y4mdenoise is as good or better - it certainly has
produced some excellent looking output for me.
Cheers,
Steven Schultz
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