Lost 10 % gain in compression when upgrading to 0.28.7

JimmyBarnes · 16th January 2004, 05:08

Upgraded from GKnot 0.28.2beta

I sometimes use TV scale instead of PC scale to gain enough compression to fit a movie on 1 CD. See:
http://forum.doom9.org/showthread.php?s=&threadid=19770

However I lost this gain after upgrading GKnot as indicated.

Does someone know why, then I might be able to have most of the benefits of GKnot 0.28.7, while retaining this better compression option. Using TV scale in this way involves the use of RGB/Full Processing Mode rather than PC scale/YUV/Fast Reprocess (barf,throw-up,vomit...)

so I'm speculating that one of the newer GKnot components doesn't allow the use of RGB

, though when one unticks Fast Reprocess and ticks show Input/Output in VDubMod, the respective input/output frames can be seen.

Uninstalling 0.28.7 and reinstalling 0.28.2beta restored the gain (after a number of other exhaustive efforts with individual apps) BTW.

thanx
JB

jggimi · 16th January 2004, 14:15

As far as I know, those color "scales" are for RGB only. And recent releases of Gknot that use AviSynth 2.5x are able to take advantage of YV12 colorspace. Since DVD video is YV12, this allows retention of the same colorspace all the way through the transcoding process.

JimmyBarnes · 16th January 2004, 23:38

Quote:

Originally posted by jggimi
As far as I know, those color "scales" are for RGB only. And recent releases of Gknot that use AviSynth 2.5x are able to take advantage of YV12 colorspace.

But would AviSynth 2.5x prohibit the use of RGB, or is there some way GKnot/AviSynth can be configured to allow its use?

thanx
JB

jggimi · 17th January 2004, 00:00

If I read the history of Gknot correctly, 0.28 was the shift to YV12.

AviSynth gets the video stream from the mpeg2dec dll. At that point, if it was a DVD source, the video is in YV12 colorspace, which is already a compressed colorspace. You could convert to RGB colorspaces, by adding a ConvertToRGB24() or a ConvertToRGB32() at the end of the script. I don't think it would give you the results you are looking for. Of course, you could test it with it.

My understanding of that scale value is that it only controls luminance ranges for RGB. Since the DVD is in YV12 to begin with, it comes out of the mpeg2dec plugin with that value unused.

I don't recall which release of DivX 5 came with 028.2, but is it possible that you're looking at the results from two different versions of the codec? DivX compression algorithms were altered completely at 5.1.

JimmyBarnes · 17th January 2004, 01:16

Quote:

Originally posted by jggimi
If I read the history of Gknot correctly, 0.28 was the shift to YV12.

I'm using GKnot 0.28.2 beta and getting the additional compression I require by using TV-scale. That compression vanishes under GK 0.28.7.

Quote:

I don't recall which release of DivX 5 came with 028.2, but is it possible that you're looking at the results from two different versions of the codec? DivX compression algorithms were altered completely at 5.1.

Didn't know GKnot rippack messed with the DivX decoder. When it installs, the list of programs/operations says nothing about changing the DivX version. I've used only DivX Pro 5.0.5 since June last year.

JB

16th January 2004, 05:08	#1 \| Link
JimmyBarnes the Interrogator Join Date: Oct 2001 Location: DownUnder Posts: 664	Lost 10 % gain in compression when upgrading to 0.28.7 Upgraded from GKnot 0.28.2beta I sometimes use TV scale instead of PC scale to gain enough compression to fit a movie on 1 CD. See: http://forum.doom9.org/showthread.php?s=&threadid=19770 However I lost this gain after upgrading GKnot as indicated. Does someone know why, then I might be able to have most of the benefits of GKnot 0.28.7, while retaining this better compression option. Using TV scale in this way involves the use of RGB/Full Processing Mode rather than PC scale/YUV/Fast Reprocess (barf,throw-up,vomit...) so I'm speculating that one of the newer GKnot components doesn't allow the use of RGB , though when one unticks Fast Reprocess and ticks show Input/Output in VDubMod, the respective input/output frames can be seen. Uninstalling 0.28.7 and reinstalling 0.28.2beta restored the gain (after a number of other exhaustive efforts with individual apps) BTW. thanx JB Last edited by JimmyBarnes; 16th January 2004 at 05:17.

16th January 2004, 14:15	#2 \| Link
jggimi Moderator Emeritus Join Date: Dec 2001 Location: The NW corner of Lake Erie Posts: 5,552	As far as I know, those color "scales" are for RGB only. And recent releases of Gknot that use AviSynth 2.5x are able to take advantage of YV12 colorspace. Since DVD video is YV12, this allows retention of the same colorspace all the way through the transcoding process.

17th January 2004, 00:00	#4 \| Link
jggimi Moderator Emeritus Join Date: Dec 2001 Location: The NW corner of Lake Erie Posts: 5,552	If I read the history of Gknot correctly, 0.28 was the shift to YV12. AviSynth gets the video stream from the mpeg2dec dll. At that point, if it was a DVD source, the video is in YV12 colorspace, which is already a compressed colorspace. You could convert to RGB colorspaces, by adding a ConvertToRGB24() or a ConvertToRGB32() at the end of the script. I don't think it would give you the results you are looking for. Of course, you could test it with it. My understanding of that scale value is that it only controls luminance ranges for RGB. Since the DVD is in YV12 to begin with, it comes out of the mpeg2dec plugin with that value unused. I don't recall which release of DivX 5 came with 028.2, but is it possible that you're looking at the results from two different versions of the codec? DivX compression algorithms were altered completely at 5.1.