Avisynth: Shorten the GOP with Cartoons?

CheronAph · #1 04-20-2003, 01:53 PM

In topic, http://www.kvcd.net/forum/viewtopic.php?t=3483 you suggest to shorten the gop with cartoons, do you mean max number of frames or...

kwag · #2 04-20-2003, 01:58 PM

Quote:

Originally Posted by CheronAph

In topic, http://www.kvcd.net/forum/viewtopic.php?t=3483 you suggest to shorten the gop with cartoons, do you mean max number of frames or...

Yes. It's currently set at 24, so change that to 12 (PAL) or 15 (NTSC)

-kwag

heller · #3 04-20-2003, 08:50 PM

Kwag, why is shortening the GOP better for anime sources?

Thanks in advance!

kwag · #4 04-20-2003, 08:55 PM

Quote:

Originally Posted by heller

Kwag, why is shortening the GOP better for anime sources?

Thanks in advance!

It reduces the compression, but because of that, the I frames are tighter together and there are less forward/backward prediction (B and P) frames between I frames. So lower compression = higher quality, less artifacts, at the expense of larger file size

-kwag

Daagar · #5 04-21-2003, 12:46 PM

Thanks Kwag! Very important info when making kvcd's for the kids

heller · #6 04-21-2003, 01:16 PM

Thanks.

telemike · #7 04-21-2003, 02:26 PM

Quote:

It reduces the compression, but because of that, the I frames are tighter together and there are less forward/backward prediction (B and P) frames between I frames. So lower compression = higher quality, less artifacts, at the expense of larger file size

-kwag

Kwag- If I am doing NTSC @ 30 fps, would reducing the GOP to 1-15-2-15 give better quality than using 1-24-2-24?

kwag · #8 04-21-2003, 02:46 PM

Quote:

Originally Posted by telemike

Kwag- If I am doing NTSC @ 30 fps, would reducing the GOP to 1-15-2-15 give better quality than using 1-24-2-24?

If it's not anime, you'll barely notice any quality difference, but file size will be much larger with a GOP of 15.

-kwag

muaddib · #9 04-21-2003, 07:08 PM

Quote:

Originally Posted by kwag

Quote:

Originally Posted by heller

Kwag, why is shortening the GOP better for anime sources?

Thanks in advance!

It reduces the compression, but because of that, the I frames are tighter together and there are less forward/backward prediction (B and P) frames between I frames. So lower compression = higher quality, less artifacts, at the expense of larger file size

-kwag

Great and clean explanation!

But that made me think... with lower compression you probably will have to lower the CQ value.
So which is better (for animes)?
Higher CQ with a larger GOP or Lower CQ with a tighter GOP?

kwag · #10 04-21-2003, 07:17 PM

Quote:

Originally Posted by muaddib

So which is better (for animes)?
Higher CQ with a larger GOP or Lower CQ with a tighter GOP?

Lower CQ with tighter GOP. The longer the GOP, the more artifacts start to show. So it's a compromise

-kwag

muaddib · #11 04-21-2003, 07:42 PM

That's why I call you KWAG - THE ONE!
There is no one faster in the matrix... her, I mean in the net!

Thanks again kwag.

BTW, did you see the full trailer of MATRIX - RELOADED?
WOW man! That sequel is going to be AMAZING

kwag · #12 04-21-2003, 10:00 PM

Oh yes, I saw the trailer. I can't wait to Co (Cough) go see it in the movies, and Co(Cough) buy the DVD