To Crop or Not to Crop! - Page 8

kwag · #**141** 12-18-2002, 10:27 AM

Quote:

Originally Posted by muaddib

For a 1CD with 704x480 I presume that the CQ_VBR should be low.
Is this gain in quality true for higher CQ_VBRs? (lets say 2CDs 704x480)
Or for higher CQ_VBRs the quality is high enough that we could use the other GOP and won't notice the degeneration in quality?

Cheers!

Hi muaddib,

What I like about this long GOP with the 2 B's, is that the visible artifacts that showed with 1-36-3-1-36 are almost gone

That is, comparing a target with identical file sizes, made with both GOP's. So for a 2 CD movie, the result must be just vomiting awesome

Just try it with KVCD Predictor and make a sample target for 2 CD's. Remember to change the error margin % from 5 to 0, because this GOP is actually more close to the real formula. That is * 1.0, and not * 0.95.

-kwag

kwag · #**142** 12-18-2002, 10:49 AM

Quote:

Originally Posted by GFR

HI,

Instead of searching and "optimal" GOP for each CQ/resolution/movie, and at the same time trying to do the file prediction, perhaps we can use a compromise solution and narrow the options, like a low-CQ GOP and a hi-CQ GOP.

With only a couple of GOPs the search space is reduced and it can be easier to find "sub-optimal" parameters that may not be as good as if we had exhaustively searched every possible GOP for every CQ for a given movie, but that are still better than always use the same GOP for every CQ.

What I'm trying to do is target a file size that is identical to the other GOP ( 1-36-3-1-26 ), but gives a higher quality ( Q. Factor ). Right now, with ( 1-12-2-1-24 ) it seems to do just that. When used with Predictor, the CQ_VBR encoding value is lower than the same material than with the longer GOP. But when both samples are encoded with their calculated CQ_VBR value for the same file size, I can see clearly that with the 1-12-2-1-24 artifacts are almost gone and the picture looks cleaner. Viewed with bit rate viewer, you can see the quality curve is closer to the bit rate curve.

-kwag

SansGrip · #**143** 12-18-2002, 11:06 AM

Quote:

Originally Posted by kwag

But when both samples are encoded with their calculated CQ_VBR value for the same file size, I can see clearly that with the 1-12-2-1-24 artifacts are almost gone and the picture looks cleaner.

So a higher CQ_VBR isn't necessarily better... Now you've really opened a can of worms

.

kwag · #**144** 12-18-2002, 11:14 AM

Quote:

Originally Posted by SansGrip

Quote:

Originally Posted by kwag

But when both samples are encoded with their calculated CQ_VBR value for the same file size, I can see clearly that with the 1-12-2-1-24 artifacts are almost gone and the picture looks cleaner.

So a higher CQ_VBR isn't necessarily better... Now you've really opened a can of worms

.

Now let's find the sweet spot

This is going to be fun

-kwag

christopher · #**145** 12-18-2002, 11:23 AM

Quote:

Originally Posted by SansGrip

Quote:

Originally Posted by christopher

I was one of the lucky ones, never lost power, but boy there was ice everywhere.

Tell me about it... My web server is located outside Raleigh and was down for about 5 days before the admin was able to find a couple of generators for sale

.

Well not much too tell. It live about 1.5 hours drive southwest of Raleigh. I would not have been such a big deal, but it caught everyone off guard. Never under estimate mother nature.

SansGrip · #**146** 12-18-2002, 03:02 PM

Quote:

Originally Posted by kwag

Try this out: 1-12-2-1-24

I just did American Pie (1h35m) at 704x480 with the above GOP structure. KVCDP overestimated yet again (I seem to have less luck with it than everyone else) with an error margin of 0%, ending up with a final size of 749mb compared to the predicted 797mb.

Anyway, I just sat and watched the first half and it looks incredible

! During regular viewing it's basically indistinguishable from a DVD, and it's only when you look closely at known problem areas (high contrast textures, etc.) that you notice worse Gibbs Effect than on a DVD.

But really, this is as good an encode as I've ever done. Not only are there nearly zero noticible DCT blocks but it's also super-sharp as you'd expect from that resolution... Now I have an encode I'm happy with, I can finally delete the vobs that have been on my HD for months!

Kwag, you're the man

.

Here's the script, in case you're curious (it's pretty standard):

Code:

AudioDub(Mpeg2Source("ap.d2v"), WavSource("ap.wav"))
#IL = Framecount / 100
#SL = round(Framerate)
#SelectRangeEvery(IL, SL)
Crop(15, 8, 692, 462)
LegalClip()
BilinearResize(692, 352)
FluxSmooth()
Blockbuster(method="noise")
AddBorders(6, 64, 6, 64)
LegalClip()
#Levels(0, 1.5, 255, 16, 255)
#ConvertToRGB()

kwag · #**147** 12-18-2002, 04:19 PM

Hey great SansGrip

So this thread wasn't a waste of time after all. Thought so there yesterday, for a moment

, but I guess something good did come out of it

I'll have to run some tests on the other resolutions, and if I get the same results, we'll say "Bye Bye" to 1-36-3-1-36" and welcome 1-12-2-1-24

and update all templates with those numbers.

-kwag

SansGrip · #**148** 12-18-2002, 04:37 PM

Quote:

Originally Posted by kwag

So this thread wasn't a waste of time after all.

No way! I did try 720x480 once (long before I discovered your templates or even contemplated writing my own Avisynth filter) and was highly unimpressed with the results. If I remember right it was awfully blocky and I swiftly abandoned the idea of going over 352x240.

But it seems that your custom matrices and GOP structures are like a magic potion. I never would have believed that 1h35m on one disc at that resolution and NO BLOCKS would be possible if I hadn't seen it for myself

.

black prince · #**149** 12-18-2002, 04:40 PM

Hi Kwag,

My latest test results:

Movie Length = 8,712 seconds, Resolution (528x480), Resize=496x352

CQ_VBR=22.42 GOP=1-12-2-1-24 File size=22,225,134
CQ_VBR=22.42 GOP=1-36-3-1-36 File size=21,533,392

Lowering CQ_VBR to come close to file size=21,533,392
CQ_VBR=20.60 GOP=1-12-2-1-24 File size=21,608,937

Picture quality was actually better using GOP=1-12-2-1-24.
This was done with no filters. Adding Blockbuster and Flux
should increase picture quality greatly. Way to go Kwag

I guess this lowers the starting CQ for kvcd templates. For
KVCDx3 it’s 25 and now it could be 22 or 23. There is probably
still more room to improve picture quality/file size/process time.

These improvements are starting to add up. Keep it comming.

-black prince

kwag · #**150** 12-18-2002, 04:54 PM

Quote:

Originally Posted by SansGrip

Quote:

Originally Posted by kwag

So this thread wasn't a waste of time after all.

No way! I did try 720x480 once (long before I discovered your templates or even contemplated writing my own Avisynth filter) and was highly unimpressed with the results. If I remember right it was awfully blocky and I swiftly abandoned the idea of going over 352x240.

But it seems that your custom matrices and GOP structures are like a magic potion. I never would have believed that 1h35m on one disc at that resolution and NO BLOCKS would be possible if I hadn't seen it for myself

.

Feels so good to hear those words

Some people "at other forums" keep saying NAH. just templates. There's nothing special. bla bla bla. And no matter how many times I try to explain that this is all about MPEG-1 optimizations, that they are put in templates ( thanks to TMPEG provisions ), they just keep saying "KVCD are just XVCD and are nothing more than templates"
Well, it has taken quite a lot of time to find these optimal parameters, and I think we're not done yet. So I would say to them, as I've said before in the "OTHER" forums, "You ain't seen nothing yet"

Thanks SansGrip

-kwag

black prince · #**151** 12-18-2002, 07:39 PM

Hey Kwag,

Are you still using Tmpgenc to mask borders and resize or have
you dropped this process.

-black prince

kwag · #**152** 12-18-2002, 08:29 PM

Quote:

Originally Posted by black prince

Hey Kwag,

Are you still using Tmpgenc to mask borders and resize or have
you dropped this process.

-black prince

I'm still trying this with the mask.

-kwag

Racer99 · #**153** 12-18-2002, 10:21 PM

Quote:

Originally Posted by kwag

Quote:

Originally Posted by SansGrip

Quote:

Originally Posted by kwag

So this thread wasn't a waste of time after all.

No way! I did try 720x480 once (long before I discovered your templates or even contemplated writing my own Avisynth filter) and was highly unimpressed with the results. If I remember right it was awfully blocky and I swiftly abandoned the idea of going over 352x240.

But it seems that your custom matrices and GOP structures are like a magic potion. I never would have believed that 1h35m on one disc at that resolution and NO BLOCKS would be possible if I hadn't seen it for myself

.

Feels so good to hear those words

Some people "at other forums" keep saying NAH. just templates. There's nothing special. bla bla bla. And no matter how many times I try to explain that this is all about MPEG-1 optimizations, that they are put in templates ( thanks to TMPEG provisions ), they just keep saying "KVCD are just XVCD and are nothing more than templates"
Well, it has taken quite a lot of time to find these optimal parameters, and I think we're not done yet. So I would say to them, as I've said before in the "OTHER" forums, "You ain't seen nothing yet"

Thanks SansGrip

-kwag

Anybody who is somebody that loves this craft of ours is really reading the posts here. Where else would the leeches get their ideas. You guys are head and shoulders ahead of them and ahead of me too. I'm trying to catch up.

Keep it up you guys. That goes for you too Black Prince, Sansgrip, Christopher, and any others I forgot to mention.

kwag · #**154** 12-18-2002, 11:48 PM

I'm currently encoding "Red Planet" one more time, with the file prediction adjusted, to take into account the new GOP difference. I'm 68% into the encode, and file size is ~545MB. Looks like it's going to be right on target. The CQ_VBR used is 11.1, much higher than the sample I posted yesterday, which was CQ_VBR 8.4 I recall. It's a HUGE difference in quality from 8.4 to 11.1. Artifacts are barely visible. So I'll let you know when the encode finishes, and hopefully validate the formula adjustments.

-kwag

Jellygoose · #**155** 12-19-2002, 09:39 AM

I thought with the new 2B GOP, the CQ_VBR should be lowered a little for getting the same file-size... how come you upped it to 11.1 ??

kwag · #**156** 12-19-2002, 09:42 AM

Quote:

Originally Posted by Jellygoose

I thought with the new 2B GOP, the CQ_VBR should be lowered a little for getting the same file-size... how come you upped it to 11.1 ??

Because the final file size was under the predicted size on the movie I did. So there was a lot of space left. Now I'm trying to zero in on the offset ( error % ) to adjust file prediction with this new GOP. Not done yet.

-kwag

kwag · #**157** 12-19-2002, 10:04 AM

Here are my results and calculations. Based on the final size I got for "Red Planet", which when muxed with audio just made it with overburn, the new % error correction for file prediction formula is 0.89 and for KVCD Predictor it's 11
I'm going to run a couple of different movies today to see if the results are consistent. This is still a test phase, and these numbers are not final. Until we get to the ~2% to ~3% we had with the old GOP, I won't be happy

Edit:
Currently encoding "Red Planet" with adjusted CQ_VBR calculated from formula: MPEG size = ((Total frames/Framerate)/100) * (MPEG sample file size * .89)
In another computer, encoding "Bugs Life" Full screen to 352x240, with same calculations. What I'm doing is testing the formula with two different movies and the resolution extremes, 352x240 and 704x480. On 352x240 using standard .avs script with default skeleton provided by FitCD. No filters of any kind. All encodes using GOP of 1-12-2-1-24

-kwag

black prince · #**158** 12-19-2002, 02:11 PM

Hi Kwag,

I'm doing some testing for the file prediction factor (i.e. 0.95) and
learned that with Blockbuster noise there's a catch-22. Picture
quality is fantastic with Blockbuster noise but, file prediction is
constantly changing. Without it file prediction is much more accurate
but, I loose the quality. My solution is to use a smaller target file
(CD - audio = video target file). Instead of 128kb audio, I'm dropping
to 112kb and using the target for this. It's not what I want but, how
can we compensate for Blockbuster noise

BTW, my encode time has increased from 6-7 hrs to 12-14 hrs using
Tmpgenc mask borders and resize. Why is Tmpgenc so slow

Picture quality is supriseingly very good at these low CQ_VBR's.
CQ_VBR=11+ is much like the old CQ_VBR=25 with the old GOP.

-black prince

kwag · #**159** 12-19-2002, 02:24 PM

Quote:

Originally Posted by black prince

Hi Kwag,
o
I'm doing some testing for the file prediction factor (i.e. 0.95) and
learned that with Blockbuster noise there's a catch-22. Picture
quality is fantastic with Blockbuster noise but, file prediction is
constantly changing. Without it file prediction is much more accurate
but, I loose the quality. My solution is to use a smaller target file
(CD - audio = video target file). Instead of 128kb audio, I'm dropping
to 112kb and using the target for this. It's not what I want but, how
can we compensate for Blockbuster noise

-black prince

The filters shouldn't change the accuracy of the formula. Only the final file size. That's the reason I'm currently encoding one movie at 704x480 with Blockbuster noise, and the other one at 352x240 without any filters. The filters should only affect CQ_VBR value, but the formula should behave the same, no matter what the source is. If it does make a big drastic difference, then we have a serious problem! Then a new test should be done, probably with a wider sampling ( more that 24 frames per shot ) to accomodate GOP size and compression factors. Hopefully, this won't be needed

. Right now, the .89 offset seems to be right on the nose

I'll know for sure when both movies are done.

-kwag

heyitsme · #**160** 12-19-2002, 03:14 PM

kwag,

I used your new file prediction methods and new technique to encode Moulin Rouge. I encoded it iwth the kvcdx3 template with fluxsmooth only and the mpeg ize came out to be 782 megs. Which is pretty close. Just wanted to let you know. Quality sure blew me off my feet. Nice......

Branden