Quantcast CQ vs. CQ_VBR ... Very Interesting... - Page 24 - digitalFAQ.com Forums [Archives]
  #461  
01-11-2003, 04:57 PM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@SansGrip,

I tried 2 CD encodes with CQ and CQ_VBR. Flashing still remains a
problem, but Gibbs is much better I also, tried your method of
manual file prediction:

((CD size - Audio) / Total Frames) * test frames) = Target File Size

It's slightly more accurate, but I was wondering how you determined
for 1 CD the capacity is 813,019,155. For 2 CD's would it be correct
to multiply by 2.

-black prince
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Site Staff / Ad Manager
 
Join Date: Dec 2002
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #462  
01-11-2003, 05:03 PM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@Kwag,

It looked bad on TV and PC. (flashing with 704x480 CQ). Also,
528x480 was a little better, but it's still noticalbe. Not until I used
352x240 did flashing disappear, but Gibbs seemed a little worst.
Seemed the higher the resolution flashing was more noticable

-black prince
Reply With Quote
  #463  
01-11-2003, 05:05 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Ok, you guys push me, so I'm going to look at this very closely
I'm going to go grab something to eat, and I'll be back in a couple of hours ( wife wants to go out ). I have something in my mind that might solve the problem.

Later ,

-kwag
Reply With Quote
  #464  
01-11-2003, 05:07 PM
SansGrip SansGrip is offline
Free Member
 
Join Date: Nov 2002
Location: Ontario, Canada
Posts: 1,135
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by black prince
It's slightly more accurate, but I was wondering how you determined for 1 CD the capacity is 813,019,155.
With a calculator . Basically:

Capacity of CD in bytes = minutes * 60 * 75 * 2324

For an 80-minute CD, that would be:

80 * 60 * 75 * 2324 = 836,640,000

A good guess for VCD/SVCD filesystem overhead is 11mb, or 11,534,336. This brings us down to:

836,640,000 - 11,534,336 = 825,105,664

We then need to compensate for the system stream, which is calculated using the following formula:

Total size = (video size + audio size) * (2048 / 201

Therefore we do:

825,105,664 * (2018 / 204 = 813,019,155

That's the total number of bytes we have available for our video and audio. Once we subtract the size of our audio from that, we have the maximum size for video.

Quote:
For 2 CD's would it be correct to multiply by 2.
160 * 60 * 75 * 2324 = 1,673,280,000
1,673,280,000 - 22 * 1024 * 1024 = 1,673,280,000 - 23,068,672 = 1,650,211,328
1,650,211,328 * (2018 / 204 = 1,626,038,310

and

813,019,155 * 2 = 1,626,038,310

In other words, "yep" .
Reply With Quote
  #465  
01-11-2003, 05:13 PM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@SansGrip,

SansGrip wrote:
Quote:
813,019,155 * 2 = 1,626,038,310

In other words, "yep" .
Thanks

-black prince
Reply With Quote
  #466  
01-11-2003, 05:17 PM
SansGrip SansGrip is offline
Free Member
 
Join Date: Nov 2002
Location: Ontario, Canada
Posts: 1,135
Thanks: 0
Thanked 0 Times in 0 Posts
@black prince

By the way, that's the formula I'm going to be using in the next release of KVCDP... It does seem to be more accurate, as you say, but it's a bit of a pain doing it manually.
Reply With Quote
  #467  
01-11-2003, 08:03 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
@black prince, jorel, SansGrip, and All@,

Download this, and tell me if the "flashing" effect is gone or not.
http://www.kvcd.net/kpax-1-12-4-1-16.mpg
Is the quality retained ( To me, it seems the same )
Is the flashing gone ( To me, yes, gone for good! )
But I need more eyes to look at it
If it is, I'll explain what it means, and why ( I assume you already see what )
Compare it to the sample I posted yesterday

-kwag
Reply With Quote
  #468  
01-11-2003, 08:15 PM
jorel jorel is offline
Invalid Email / Banned / Spammer
 
Join Date: Aug 2002
Location: Brasil - MG - third stone from the sun
Posts: 5,570
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kwag
@black prince, jorel, SansGrip, and All@,

Download this, and tell me if the "flashing" effect is gone or not.
http://www.kvcd.net/kpax-1-12-4-1-16.mpg
Is the quality retained ( To me, it seems the same )
Is the flashing gone ( To me, yes, gone for good! )
But I need more eyes to look at it
If it is, I'll explain what it means, and why ( I assume you already see what )
Compare it to the sample I posted yesterday

-kwag
i see in powerdvd,seems......

amazing
can't see any problem! (perfect color cubs,skin faces..... )

see in zoomplayer too,a little dark and some blocks in dark!
Reply With Quote
  #469  
01-11-2003, 09:27 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Expect more changes tonight on the GOP. My goal is to find an optimal value to match the quality of the 1-12-1-1-24 at the same file size. This thread will be polluted by me with samples. But when I put my mind on something, I "sock it to it" until I get what I want
So stay tunned, and compare the samples I'll start to post until we all agree that it matches the "Almost Gibbs free" kpax-newgop-newmat.mpg sample, but better stable background without flashes. This is the reference sample and size that I am focusing on right now.

-kwag
Reply With Quote
  #470  
01-11-2003, 09:31 PM
SansGrip SansGrip is offline
Free Member
 
Join Date: Nov 2002
Location: Ontario, Canada
Posts: 1,135
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kwag
Compare it to the sample I posted yesterday
I see (in WMP) fairly strong quantization in low frequencies, yet an increase in Gibbs. No flashing though .
Reply With Quote
  #471  
01-11-2003, 09:54 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Tunning, tunning.....

-kwag
Reply With Quote
  #472  
01-11-2003, 10:04 PM
SansGrip SansGrip is offline
Free Member
 
Join Date: Nov 2002
Location: Ontario, Canada
Posts: 1,135
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kwag
Tunning, tunning.....
Making progress?

(I just realized... The more time you spend doing this, the less time you spend playing with GripFit )
Reply With Quote
  #473  
01-11-2003, 10:13 PM
muaddib muaddib is offline
Free Member
 
Join Date: Jun 2002
Location: S„o Paulo - Brasil
Posts: 879
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kwag
Expect more changes tonight on the GOP. My goal is to find an optimal value to match the quality of the 1-12-1-1-24 at the same file size. This thread will be polluted by me with samples. But when I put my mind on something, I "sock it to it" until I get what I want
So stay tunned, and compare the samples I'll start to post until we all agree that it matches the "Almost Gibbs free" kpax-newgop-newmat.mpg sample, but better stable background without flashes. This is the reference sample and size that I am focusing on right now.

-kwag
Thatís why i LOVE this place!
Those flashes are (were) really annoying.
Reply With Quote
  #474  
01-11-2003, 10:59 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by SansGrip
Quote:
Originally Posted by kwag
Tunning, tunning.....
Making progress?
Take a look, and tell me SERIOUSLY what you think. If you see any , tell me. If it's , say it too

Original reference:
http://www.kvcd.net/kpax-newgop-newmat.mpg
New test model:
http://www.kvcd.net/kpax-1-24-4-1.24.mpg
Quote:

(I just realized... The more time you spend doing this, the less time you spend playing with GripFit )
Ahh, chucks

-kwag
Reply With Quote
  #475  
01-11-2003, 11:07 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Need some testers here

Encode a sample ( 15 second or so ) with GOP 1-12-1-1-24 and another sample of the same 15 second clip with GOP 1-24-4-1-24.
Play with CQ of second sample until size matches size of first sample. Then make a visual comparison.
Use KVCD BETA-1a Notch Matrix for both.

-kwag
Reply With Quote
  #476  
01-11-2003, 11:21 PM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@Kwag,

I created two 30 second samples. One with the GOP 1-12-1-1-24 and
the other using 1-24-4-1-24. I used file predictor to create the second
file by setting the target file size to the size of the first test file.
I agree with SansGrip, that the flashing is much improved. It appeared
to be there but much less noticable. I viewed the samples up close on
my PC and TV. Up close, meaning, within one foot. From 5+ feet,
It's not noticable. There was some Gibbs, but maybe your CQ settings
were not very high. I realize that flashing can not be completely
eliminated, but if it reduced to a point where it's not noticable that'ss
just as good.

-black prince
Reply With Quote
  #477  
01-11-2003, 11:23 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by muaddib
Those flashes are (were) really annoying.
I think I learned my lesson on GOP. "If you have a lot of "Pees", you also need some to fill in with some "Bees" :tongue2:
Reply With Quote
  #478  
01-11-2003, 11:32 PM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by black prince
There was some Gibbs, but maybe your CQ settings
were not very high.
Yes, the CQ I used is not the CQ to fit the movie on one CD. It's lower, so I could enhance the visible blocks and artifacts.

I can't see flashing anymore on that scene . At least on that last sample I posted. I'll encode something else. As far as Gibbs, they're actually there, but they're "smoothed" because of the additional B frames, so they don't show as sharp as with 1-12-1-1-24.

-kwag
Reply With Quote
  #479  
01-11-2003, 11:47 PM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@Kwag,

Without realizing it, you are using psychovisual techniques. Reducing
picture effects the are very noticable and enhancing those the vision
focuses on more often. It's like listening to music and realizing the
audio range of the ear will never notice certain imperfections and
others it will pick very quickly. Knownig which visual effects are
ignored and which are very accute to sight is useful to creating
high quality video with greater compression. I think it's really interesting
and fun tweaking this process towards that goal.

-black prince
Reply With Quote
  #480  
01-12-2003, 12:06 AM
kwag kwag is offline
Free Member
 
Join Date: Apr 2002
Location: Puerto Rico, USA
Posts: 13,537
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by black prince
Without realizing it, you are using psychovisual techniques.
Yes, and we all will become Psychos soon ( Just kidding )
Quote:
Reducing picture effects the are very noticable and enhancing those the visionfocuses on more often.
You're right on target . The BETA-1a notch matrix has a strong effect on the low frequency domain of the material, causing a drop on visual DCT blocks and a blending effect on the blocks. Then on the high frequency end of the spectrum, the long GOP "blurrs" the artifacts for a more pleasing view.
Quote:
It's like listening to music and realizing the audio range of the ear will never notice certain imperfections and others it will pick very quickly.
That sounds very much like some of the principles used on MP3s, where very close frequencies that the human ear can't make the difference, the lower level signal is discarded. That's how we get compression .
Quote:
Knownig which visual effects are ignored and which are very accute to sight is useful to creating
high quality video with greater compression. I think it's really interesting
and fun tweaking this process towards that goal.
I think we're very close to that goal now

-kwag
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Avisynth: Interesting results with YlevelsS supermule Avisynth Scripting 2 08-06-2006 11:59 PM
Avisynth: Interesting ASharp phenomenon... audioslave Avisynth Scripting 12 10-23-2003 06:36 AM
Interesting info about the Luminance Level in CCE digitalize Video Encoding and Conversion 0 04-28-2003 12:29 PM
A couple of interesting links.. kwag Off-topic Lounge 0 12-31-2002 03:47 PM
KVCD: Interesting poll found kwag Video Encoding and Conversion 2 12-31-2002 02:44 AM

Thread Tools



 
All times are GMT -5. The time now is 12:27 PM  —  vBulletin © Jelsoft Enterprises Ltd