To Crop or Not to Crop! - Page 17

kwag · #**321** 12-22-2002, 12:25 AM

Quote:

Originally Posted by SansGrip

Just watched Resident Evil (352x480, CQ_VBR 15.55) and it looks very good -- not DVD quality due to the relative softness, but still very watchable and of course a lot sharper than standard VCD. Also the bitrate was high enough that there was hardly any noticible Gibbs...

Again, though, I had that freezing at the beginning of the disc. However this time there was very bad corruption at the end, video and audio, but only in the last 5 minutes or so.

Is this another symptom of too-low minimum bitrate?

At the end credits? Yes. Did it happen anywhere on the movie? If it didn't, then it's the MIN bit rate at the point where it switches to end credits, and during end credits. There's just too much black there. You might just want to fix your MIN bit rate to 450Kbps. That should keep a steady low bit rate stream that is high enough to kill that effect.

I'm still tweaking prediction. I'm now at 512:6. Running two sample encodes on two machines.

-kwag

SansGrip · #**322** 12-22-2002, 12:32 AM

Quote:

Originally Posted by black prince

Finally figured out how to get FitCD to crop

It's even more useful than you first thought, isn't it?

Quote:

I used LanczosResize which add sharpening

In fact it doesn't really add sharpening so much as retain existing sharpness. The other resizers (except for "precise bicubic") soften the image. Lanczos is about the most "accurate" resizer there is, but it's bad for us because we want that extra compressibility that softness brings

.

Quote:

Thanks for being patient in answering my questions

No worries. Glad you got FitCD figured out

.

SansGrip · #**323** 12-22-2002, 12:35 AM

Quote:

Originally Posted by kwag

At the end credits? Yes. Did it happen anywhere on the movie?

Yes -- about the last two or three minutes of the movie. It started with a single audio glitch (one of those real loud ones) and progressively got worse as time passed.

I'm still tweaking prediction. I'm now at 512:6. Running two sample encodes on two machines.

I'm testing too, but in the other direction -- 25:96 right now

.

kwag · #**324** 12-22-2002, 12:49 AM

128:24 seems to be hitting the target very accurately.

When this thing finally stabilizes, we're going to have to write a "Readme.txt" or something, because I think everyone reading this thread must be either asking for some hard liquor or going bananas changing prediction parameters

-kwag

SansGrip · #**325** 12-22-2002, 12:56 AM

Quote:

Originally Posted by kwag

128:24 seems to be hitting the target very accurately.

Sounds logical, too...

Quote:

When this thing finally stabilizes, we're going to have to write a "Readme.txt" or something, because I think everyone reading this thread must be either asking for some hard liquor or going bananas changing prediction parameters

Yes, I hope no-one is trying to track this in real-time

. Actually I intend to write up a howto while I'm away for Christmas (24th, 25th, 26th). Thank goodness for the laptop...

kwag · #**326** 12-22-2002, 01:32 AM

I smell something is burning.

Oh, look out, it must be SansGrip's mind running a prediction test loop

-kwag

muaddib · #**327** 12-22-2002, 01:33 AM

Quote:

Originally Posted by SansGrip

Yes, I hope no-one is trying to track this in real-time

.

Hey! Of course we are tracking it!
Well, at least we are trying...

Just hope that you guys don't get lost in the middle of all this variation of granularity and window/sample length.

SansGrip · #**328** 12-22-2002, 01:36 AM

Quote:

Originally Posted by muaddib

Just hope that you guys don't get lost in the middle of all this variation of granularity and window/sample length.

Who said that??

kwag · #**329** 12-22-2002, 01:52 AM

Quote:

Originally Posted by SansGrip

Quote:

Originally Posted by muaddib

Just hope that you guys don't get lost in the middle of all this variation of granularity and window/sample length.

Who said that??

What's my name

, where am I

-kwag

muaddib · #**330** 12-22-2002, 02:48 AM

Come on guys, give us something...
I have a movie here that is willing to be predicted!

What should I use?
I made some samples with these strange settings (512:6, 128:24, 25:96) and all came out with very different prediction.

SansGrip · #**331** 12-22-2002, 02:52 AM

Quote:

Originally Posted by muaddib

Come on guys, give us something...

We're minutes away from having a formula that should work for tonight

.

kwag · #**332** 12-22-2002, 03:28 AM

Drums rolling /\/\/\/\/\/\/\/\/\/\ ........

SansGrip · #**333** 12-22-2002, 03:38 AM

Ok, after hours of testing and (in my case at least) ingesting caffeine, here is the latest file prediction formula...

Count all the chairs in the movie EXCEPT those with arms, then find the square root. Multiply by your favourite cousin's birthday and add 6. Calculate that value to the power of how many eggs you've eaten in the last two years, then divide by 12 and subtract quite a bit. Swap all digits, convert to hex, and simmer for 45 minutes while stirring constantly.

Then throw that value away, because what you really do is...

Let's say your movie is 96 minutes long, and we're using the new GOP structure with a maximum length of 24. This is the line you'd insert into your Avisynth script to get the sample strip:

Sampler(96, 24)

Pretty simple, eh? If your movie is 115 minutes long, it'd be:

Sampler(115, 24)

This will then give you a nice sample strip. You then do the formula as usual, with an error margin of 2% (in KVCDP) or 0.98 if you do it manually.

If I left anything out, kwag'll fix it

.

Have fun and test lots and let us know...

kwag · #**334** 12-22-2002, 03:48 AM

And here's the old ( hard core ) way

This is what you add to the end of your .avs script:

Code:

IL = MovieTimeInMinutes
SL = 24
SelectRangeEvery(IL,SL)

Or automatic:

Code:

IL = round((Framecount/Framerate)/60)
SL = round(Framerate)
SelectRangeEvery(IL,SL)

And then use the new formula:

Code:

MPEG size = (( Total frames/MovieTimeInMinutes)/24) * (MPEG sample file size * .98 )

Note: For PAL users, use 25 instead of 24 for the value of SL and change the 24 to 25 in the formula. If any NTSC user has to encode at 29.97, then use a value of 30.

And if I screwed up, SansGrip will fix it

-kwag

SansGrip · #**335** 12-22-2002, 03:53 AM

By the way, before you ask: yes, it really did take us that long to come up with something that simple

. However we're now hopefully on surer ground wrt the formula and I'm fairly confident that the error margin is now set correctly.

Of course, kwag suggested all this days ago. We just had to run everything from Sampler(20, 200) to Sampler(1200, 2) in order to discover that he was, as usual, right all along

.

Thank you and goodnight

.

kwag · #**336** 12-22-2002, 03:58 AM

Thanks for all your time and suggestions SansGrip

This was like a roller coaster. Encode, change, encode, reformulate, encode....

Now after seeing all the tests you did, I am also very confident that the file prediction is far better than what we had before.

BIG THANK YOU

Now, I'm going to bed

Good night all.

-kwag

jorel · #**337** 12-22-2002, 05:57 AM

sansgrip wrote:

"In fact it doesn't really add sharpening so much as retain existing sharpness. The other resizers (except for "precise bicubic") soften the image. Lanczos is about the most "accurate" resizer there is, but it's bad for us because we want that extra compressibility that softness brings . "

yes,i'm with you.
in my tests i really see the difference.
i "mix" with Blockbuster.....cool.

Jellygoose · #**338** 12-22-2002, 07:37 AM

Since this thread is kinda all about everything, and nobody pays attention to any other one at the moment

maybe someone can help me with this one...

with the new GOP I encoded frequency again, at 704x576 PAL, and result was really watchable... Usually I only encode in MPEG2 and mux with BBMPEG. I did the same thing with this movie, after encoding the audio with Headache. I muxed it as VCD VBR, forced mux rate 0, write program endcode checked.
The video and audio are fine in sync on my PC, but viewed on my standalone (which plays all KVCDs fine, when i muxed them together with BBMPEG) the audio is slightly too early from the beginning... that never happened before...

any suggestions?

muaddib · #**339** 12-22-2002, 08:55 AM

Quote:

Originally Posted by kwag

And then use the new formula:

Code:

MPEG size = (( Total frames/MovieTimeInMinutes)/24) * (MPEG sample file size * .98 )

Wow, that's weird... Total frames/MovieTimeInMinutes? Can you explain it a little bit?

muaddib · #**340** 12-22-2002, 09:42 AM

Quote:

Originally Posted by muaddib

Wow, that's weird... Total frames/MovieTimeInMinutes? Can you explain it a little bit?

It's ok... I got it.

It would be easier to understand if it was:

Code:

MPEG size = ((Total frames/Framerate)/MovieTimeInMinutes) * (sample file size * .98 )

Or even easier (just for my understanding):

Code:

MPEG size = (sample file size / sample length) * movie length * .98
length in seconds

Anyway, I just needed to understand it to not get crazy... the formula is as good as always!
Nice work!