Quantcast CQ vs. CQ_VBR ... Very Interesting... - Page 6 - digitalFAQ.com Forums [Archives]
  #101  
12-27-2002, 03:26 AM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@Kwag and SansGrip,

Problems with file predictor for CQ greater than 80. Seems Tmpgenc opens the bitrate
flood gates beyond this point and throws off the formula by a large amount. File
prediction told me the new is CQ 85.871 (14.4% too small) after using CQ 75. Then
test file size jumps from 21,406,846 (CQ=75) to 32,826,302 (CQ=86). File prediction
then suggests using new CQ 66.67 ??????? Iím using 2 CDís with a target video size
of 1,425,637,201. The file size formula works with no problems using CQ_VBR.
Maybe CQ reacts differently at various CQ settings to controlling bitrates.

Also, is there a KVCD template for 528x480 using CQ or how can I
change KVCDx3 to use CQ.

Finally, has SansGrip compared 704x480 to 528x480 resolutions for
CQ with same target file. I think movie length and resolution are the
major factors for high picture quality using CQ. For example, if you must use
1 CD (800MB) and you video target file size is 700MB then a long
movie (2+hrs) will not have the best quality using 704x480 as it
would with 528x480 or 352x480.

Thanks


-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
  #102  
12-27-2002, 05:15 AM
Jellygoose Jellygoose is offline
Free Member
 
Join Date: Jun 2002
Location: Germany
Posts: 1,288
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by black prince
@Kwag and SansGrip,

Problems with file predictor for CQ greater than 80. Seems Tmpgenc opens the bitrate
flood gates beyond this point and throws off the formula by a large amount. File
prediction told me the new is CQ 85.871 (14.4% too small) after using CQ 75. Then
test file size jumps from 21,406,846 (CQ=75) to 32,826,302 (CQ=86). File prediction
then suggests using new CQ 66.67 ??????? Iím using 2 CDís with a target video size
of 1,425,637,201. The file size formula works with no problems using CQ_VBR.
Maybe CQ reacts differently at various CQ settings to controlling bitrates.

Also, is there a KVCD template for 528x480 using CQ or how can I
change KVCDx3 to use CQ.

Finally, has SansGrip compared 704x480 to 528x480 resolutions for
CQ with same target file. I think movie length and resolution are the
major factors for high picture quality using CQ. For example, if you must use
1 CD (800MB) and you video target file size is 700MB then a long
movie (2+hrs) will not have the best quality using 704x480 as it
would with 528x480 or 352x480.

Thanks


-black prince
just change it black prince... my LOTR Sample is made that way, you can download it from the third page of this thread or so...
__________________
j3llyG0053
Reply With Quote
  #103  
12-27-2002, 05:55 AM
syk2c11 syk2c11 is offline
Free Member
 
Join Date: Jun 2002
Posts: 290
Thanks: 0
Thanked 0 Times in 0 Posts
Hi Kwag,
" I also confirmed SansGrip's findings that adding Blockbuster "Noise" just makes the quality worse. I believe there is a treshold point to use Blockbuster. If there is enough bit rate available for an encode, then we can use Blockbuster "noise" method to our advantage. "

Does the above statement apply to CQ_VBR mode (KVCD-Plus--704x480)? What about KDVD (Full-D1)?

Side issue: Is DVD Patcher only applicable to Mpeg-2? If not, we can "fool" those standalone DVD player which does not like KVCDx3 then.
Reply With Quote
  #104  
12-27-2002, 08:08 AM
Jellygoose Jellygoose is offline
Free Member
 
Join Date: Jun 2002
Location: Germany
Posts: 1,288
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for the Mini-HowTo kwag!

I just found out another interesting thing.
Using TemporalSmoother(2,2) even for DVD-Rips is not too bad of an idea! Try it out, it gives a little more compression than the value 2,1 and the thing that is strange to me is : Q-Level decreases from 2.66 w/ TempSmooth 2,1 to Q-Level 2.64 w/ TempSmooth 2,2.

Regarding visible differences I can't give you a lot of testing because my eyes aren't that good. I don't see a difference, only that of course the higher the value, the smoother the image... that's not necessarily a bad thing i guess....
Try it out...
__________________
j3llyG0053
Reply With Quote
  #105  
12-27-2002, 08:27 AM
jamesp jamesp is offline
Free Member
 
Join Date: Jul 2002
Location: Chelmsford, UK
Posts: 130
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Jellygoose
Thanks for the Mini-HowTo kwag!

I just found out another interesting thing.
Using TemporalSmoother(2,2) even for DVD-Rips is not too bad of an idea! Try it out, it gives a little more compression than the value 2,1 and the thing that is strange to me is : Q-Level decreases from 2.66 w/ TempSmooth 2,1 to Q-Level 2.64 w/ TempSmooth 2,2.

Regarding visible differences I can't give you a lot of testing because my eyes aren't that good. I don't see a difference, only that of course the higher the value, the smoother the image... that's not necessarily a bad thing i guess....
Try it out...
TempSmooth(2,2) definately gives you more compression. I use that value as a last resort if I need some more compression. However, i feel the picture really suffers at times. Look at skin tones and flat walls, things start to feel a little unnatural. IMHO, temporalsmoother is an amazing filter. Set it to 4 or 5 and see those filesizes shrink like mad. I use it on some cartoon tv captures at 5, it really gives some serious compression then.

Jim
Reply With Quote
  #106  
12-27-2002, 09:27 AM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
@Kwag and SansGrip,

Quote:
Black prince wrote:
Problems with file predictor for CQ greater than 80. Seems Tmpgenc opens the bitrate
flood gates beyond this point and throws off the formula by a large amount. File
prediction told me the new is CQ 85.871 (14.4% too small) after using CQ 75. Then
test file size jumps from 21,406,846 (CQ=75) to 32,826,302 (CQ=86). File prediction
then suggests using new CQ 66.67 ??????? Iím using 2 CDís with a target video size
of 1,425,637,201. The file size formula works with no problems using CQ_VBR.
Maybe CQ reacts differently at various CQ settings to controlling bitrates.
This time I tried the guide Kwag posted for manual file prediction and
the same thing is happening. At about CQ 80 or greater the file size
takes a huge increase. Again I used 2 CD's for a movie that's 138 minutes
and the manual prediction fails for CQ > 80. Is there anyone else
having this problem

-black prince
Reply With Quote
  #107  
12-27-2002, 09:38 AM
black prince black prince is offline
Free Member
 
Join Date: Jul 2002
Posts: 1,224
Thanks: 0
Thanked 0 Times in 0 Posts
Hi All,

Black prince wrote:
Quote:
Also, is there a KVCD template for 528x480 using CQ or how can I
change KVCDx3 to use CQ.
I tried KVCDx3 (528x480) as CQ instead of CQ_VBR and the results
were not as good as 704x480 CQ. The Q-Matrix is probably tuned for
CQ_VBR. It did produce a smaller file size, but for 1 CD and 138
minute movie, the CQ_VBR was much better. CQ definately has the
better picture quality given the same file size. I just hope I can solve
my problems with file size prediction

-black prince
Reply With Quote
  #108  
12-27-2002, 10:59 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
CQ definately has the
better picture quality given the same file size.

-black prince
Hi black prince,

This is the only way we can measure quality of encodings. We can't judge CQ_VBR over CQ if the file sizes are different. Right now, if I make a sample test with CQ_VBR and I make another one with CQ and adjust the value until the size matches that of the CQ_VBR sample, the CQ sample runs rings on quality around CQ_VBR! Every time

-kwag
Reply With Quote
  #109  
12-27-2002, 11:28 AM
Jellygoose Jellygoose is offline
Free Member
 
Join Date: Jun 2002
Location: Germany
Posts: 1,288
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kwag
Quote:
Originally Posted by black prince
CQ definately has the
better picture quality given the same file size.

-black prince
Hi black prince,

This is the only way we can measure quality of encodings. We can't judge CQ_VBR over CQ if the file sizes are different. Right now, if I make a sample test with CQ_VBR and I make another one with CQ and adjust the value until the size matches that of the CQ_VBR sample, the CQ sample runs rings on quality around CQ_VBR! Every time

-kwag
Same here.... I encoded Lord Of The Rings yesterday at 528x576, with a 128kb audio track, and this is the best DVD backup i have ever made. actually the best I've seen so far ...
well right now I'm doing another one, at 544x576 and it looks as if it would come out even better. I'm able to use almost the same CQ (only decrease by 1.2), and this way the movie will even look more sharp...

more to come...
__________________
j3llyG0053
Reply With Quote
  #110  
12-27-2002, 03:17 PM
rendalunit rendalunit is offline
Free Member
 
Join Date: Apr 2002
Location: san jose, Ca
Posts: 1,148
Thanks: 0
Thanked 0 Times in 0 Posts
hey all, I've been testing my butt off I finally put Pearl Harbor (~3 hrs) on one cd with the the latest LBR template and had great results.

I used CQ = 70 (much less artifacts than CQ-VBR)
min bitrate - 300
max bitrate - 1000
spoilage- p-0 b-10

avg. bitrate (viewed with bitrate viewer) is ~500kbps

LoadPlugin("D:\encoding\MPEG2DEC.dll")
LoadPlugin("C:\encoding\fluxsmooth.dll")
LoadPlugin("C:\encoding\LegalClip.dll")
AviSource("D:\PEARL_HARBOR_DSC1\VIDEO_TS\PEARL_HAR BOR_d2v-vfapi.avi")
ConvertToYUY2()
LegalClip()
BicubicResize(336,168,0,0.6,0,0,720,480)
TemporalSmoother(2,2)
fluxsmooth()
legalclip()
AddBorders(8,36,8,36)

I'm much happier with precise bicubic resize at 352x240 it's more sharp than bilinear but not too sharp like Lanczos. Good results with the double noise filters too- I tried Unfilter but there were white lines on the right and left sides. Also Blockbuster made the file size grow too much.

encoded the audio at 112kbps and after I cut the credits off, final file size 812mb

One big problem though is that the audio gets out of synch. I have a feeling that this might be due to the fact that I disabled padding so that the min. bitrate falls well below 300kbps in spots. I'm going to enable padding and check the audio synch and I'll see if this movie will still fit.
Reply With Quote
  #111  
12-27-2002, 04:02 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
Hi all, hope you had a good holiday. I personally ate three times my own bodyweight of cake and pudding .

Glad to see lots of testing has been done in my absence, and I'm keen to make some more encodes this evening. I'm not going to try to reply to every message, but I'll address some of the points that jumped out at me.

First, I stand by my assertion that at least with the material I tested, CQ mode works far better than CQ_VBR at 528x480 and above, while CQ_VBR is better for resolutions below that. That said, my final decision on the matter will have to wait until I make more encodes with difference source material .

As far as the use of Blockbuster goes, kwag is quite right when he says that if you can afford the larger file size, it will improve the quality noticibly wrt to blockiness. If you're trying to cram a very long movie on one disc, however, you need all the bits you can get, and this will almost always mean dropping Blockbuster and jacking up the smoothing. It will also help if you reduce the size of the "actual" frame itself by using overscan blocks left and right, and possibly cropping a little off the top and bottom. The more black, the better. Of course all these measures will compromise quality, but that's unavoidable.

Regarding automating file prediction, I'm going to release a new version of KVCD Predictor once things have stabilized a bit. I'm trying to come up with some ways of automating it further and making it easier to use.

Now to test...
Reply With Quote
  #112  
12-27-2002, 05:07 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
Welcome back SansGrip

-kwag
Reply With Quote
  #113  
12-27-2002, 06:37 PM
rendalunit rendalunit is offline
Free Member
 
Join Date: Apr 2002
Location: san jose, Ca
Posts: 1,148
Thanks: 0
Thanked 0 Times in 0 Posts
CQ 68.m1v 6.936 mb
CQ_VBR 21.m1v 7.106 mb

I set max bitrate back to 1150 since 1000 barely made any difference at all.

the cq sample looks a little less "mosquitoey" to me.
Reply With Quote
  #114  
12-27-2002, 07:23 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 rendalunit
the cq sample looks a little less "mosquitoey" to me.
I disagree -- I think in fact the opposite is true. Take a look at this framegrab from both versions:



I have outlined the areas where the Gibbs is particularly noticible. In each case, the effect is worse in the CQ version.

For me, this confirms my feeling that CQ_VBR is better at resolutions lower than 528x480, but am still testing that resolution and higher.
Reply With Quote
  #115  
12-27-2002, 08:17 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
What resolution was this SansGrip?

Edit: Never mind, I see it's 352x240.

-kwag
Reply With Quote
  #116  
12-27-2002, 08:19 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
What resolution was this SansGrip?
I took the 352x240 originals and cropped the borders, combined into one frame with Avisynth, then pasted that frame to Photoshop and doubled the size for clarity.
Reply With Quote
  #117  
12-27-2002, 08:22 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
I also think the CQ version is more blocky. Look at the cheek of the girl in the bottom-middle of the frame.
Reply With Quote
  #118  
12-27-2002, 08:25 PM
rendalunit rendalunit is offline
Free Member
 
Join Date: Apr 2002
Location: san jose, Ca
Posts: 1,148
Thanks: 0
Thanked 0 Times in 0 Posts
wow SansGrip, that was very cool of you to evaluate the two samples and actually post screenshots of the two for comparison The CQ_VBR sample definitely looks better than the CQ sample in your screenshot.

I wonder if the majority of the frames in the CQ-VBR sample have less Gibbs than the CQ sample

I need to learn how to cap screenshots like that- how'd you do that

thanx,
ren
Reply With Quote
  #119  
12-27-2002, 08:32 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 rendalunit
wow SansGrip, that was very cool of you to evaluate the two samples and actually post screenshots of the two for comparison
Well, if you're gonna compare then you might as well do it properly .

Quote:
I wonder if the majority of the frames in the CQ-VBR sample have less Gibbs than the CQ sample
They do. I stepped through most of the frames and only picked that one because it showed the difference most clearly.

Quote:
I need to learn how to cap screenshots like that- how'd you do that
First I load each MPEG file into VirtualDub, crop the borders and save as an AVI compressed with the lossless Huffy codec (though you could equally save it as an uncompressed AVI, but it'll be twice the size).

Edit: This step would be unnecessary if there were an Avisynth plugin to load MPEG-1 files. There may well be; I've not looked for one .

I then use an Avisynth script like this:

Code:
clip1 = AviSource("cq-68.avi").Subtitle("CQ-68")
clip2 = AviSource("cq-vbr-21.avi").Subtitle("CQ-VBR-21")
StackVertical(clip1, clip2)
Levels(0, 1.5, 255, 16, 255)
ConvertToRGB()
and load the script back into VirtualDub. I can then step through the clip a frame at a time, which is much easier than trying to view one then the other.

If I want to take a "grab" of a particular frame I select "Copy source frame to clipboard" and paste it into Photoshop where I can tweak as necessary and save as an image.
Reply With Quote
  #120  
12-27-2002, 08:44 PM
rendalunit rendalunit is offline
Free Member
 
Join Date: Apr 2002
Location: san jose, Ca
Posts: 1,148
Thanks: 0
Thanked 0 Times in 0 Posts
Great, I compared various frames of each sample to each other in Photoshop and the CQ-VBR sample is clearly better.

I learned something else new: the samples look better when I view them with WinDVD rather than Zoom player (I don't know why that is )

Thanks,
ren
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 09:28 AM  —  vBulletin © Jelsoft Enterprises Ltd