Resize Filters & Noise

[goofy183]

I'm hoping someone (anyone) with some experiance encoding could offer a few words of advice.

To start out with, I'm encoding Stargate episodes and worried much more about final quality than I am space. My only requirement is that a 45 minute episode be 700MB or less.

I've encoded about 10 of the episodes in more ways than I can count and while some settings work well for some episodes they may produce a large ammount of noise in others. I can mostly attribute this to the wide difference in each episode. An example is the list of compressibility test values from the first few episiodes: (.225, .593, .275, .432, .248, .291, .267).

Now on to my questions.

First off is resize filters. I've done quite a bit of looking through the forums about different resize filters. Most everything I've seen indicates that Sharp Bicubic is "The Best" filter and Neutral Bicubic is pretty good for still getting low compressablity values. Now some episodes seem to handle the Sharp filter better than others. A few have a lot of noise around any hard border like lines in a scope or a persons body. Others look marvolous. The best I can figure is this depends on the ratio of bits/pixel compaired to the "lossless" case presented by the comp test.

Something else that I haven't been able to find is the issue of not resizing the movie. What would happen if I 1:1 encoded and got a 720x480 output movie? Would it play in say the DIVX player or Windows Media player? Would some of the noise problems be removed because of not having to resize the video? Is the noise more of a product of the divx codec itself and not the resize filter?

The last question is something I haven't been able to find very much on either. What exactly does a noise filter do to the movie and what are pros/cons. I've read most all the guides and am fairly comfortable with GKnot and the proccesses that it automates for you. Are there more resize/noise filter options than AVIsynth shows? (I think thats what gknot uses, I could very well be mistaken)

Just so you know. I'm encoding with B-Frames and GMC with the 5.0.2 Pro codec.

I'm hoping that the best answer isn't "Trial and error" because I have to IVTC these things so it takes forever and a day to encode (or 3 hours but close enough).


-Goofy

[hakko504]

Originally posted by goofy183
I've encoded about 10 of the episodes in more ways than I can count and while some settings work well for some episodes they may produce a large ammount of noise in others. I can mostly attribute this to the wide difference in each episode. An example is the list of compressibility test values from the first few episiodes: (.225, .593, .275, .432, .248, .291, .267).These values are not interesting after a compression test. use the percentage values instead: they should be between 60 and 80% if you want good video.First off is resize filters. I've done quite a bit of looking through the forums about different resize filters. Most everything I've seen indicates that Sharp Bicubic is "The Best" filter and Neutral Bicubic is pretty good for still getting low compressablity values. Now some episodes seem to handle the Sharp filter better than others. A few have a lot of noise around any hard border like lines in a scope or a persons body. Others look marvolous. The best I can figure is this depends on the ratio of bits/pixel compaired to the "lossless" case presented by the comp test.

The problem with sharp edges is called ringing, and Sharp resizing will produce more of that compared to neutral. You can also try Lanczosresize(x,y) It will give you just as sharp picture as sharp bicubic, but usually with less ringing noise.

Something else that I haven't been able to find is the issue of not resizing the movie. What would happen if I 1:1 encoded and got a 720x480 output movie? Would it play in say the DIVX player or Windows Media player? Would some of the noise problems be removed because of not having to resize the video? Is the noise more of a product of the divx codec itself and not the resize filter?

Not resizing and playing it in WMP will look awful. This is because WMP (and DivX player I think) cannot resize during play. Use Zoom Player or BSplayer to do this.

The last question is something I haven't been able to find very much on either. What exactly does a noise filter do to the movie and what are pros/cons. I've read most all the guides and am fairly comfortable with GKnot and the proccesses that it automates for you. Are there more resize/noise filter options than AVIsynth shows?

Yes, Lanczosresize is also available. And MarcFD released a fast bicublin resize a while ago. I think it needs AviSynth2.5 though. Read some more at AviSynth.org (http://www.avisynth.org)
I'm hoping that the best answer isn't "Trial and error" because I have to IVTC these things so it takes forever and a day to encode (or 3 hours but close enough). When you start encoding, most of it is trial and eror I'm afraid. It will take you a while to get the feel for it, and then things will become easier.

[goofy183]

On the compressibility tests here are the percentages I get if I try to do all the episodes at the same 704x384 resolution. (113.55% 43.08% 92.91% 59.14% 103.03% 87.80% 95.70%)

Obviously some of the episodes don't make it to the 700MB max if the percentage is near or over 100. On those episodes is it a better idea to turn off B-Frames? On the episiodes I tried it on I really couldn't tell and my only qualm is that without B-Frames the "Max" quality is not achived because the resulting file is 700MB meaning that it could have been larger.

Is Lanczosresize(x,y) included in the libraries for GKnot or do I need another library from somewhere?

Oh and on the compression test, does gknot just use the default values for B-Frames, GMC and such when invoking the codec on the segments of video?

[hakko504]

43% is way too low: consider move this to 2 CD's.
59% could use some filtering
87% & 95% can be left as they are
103% Change to lanczosresize, make another compression test, and if still above 100%, turn off b-frames.
113% turn b-frames off, make another compression test, and if still above 100%, change to lanczosresize

Lanczos resize should be built in if you are using the system pack that came with GKnot .27. It is built into all current versions of AviSynth (I think it was added in 2.06)

b-frames themselves have a lower quality than p-frames, so you'll most likely end up with a better quality if they are turned off.

Oh and on the compression test, does gknot just use the default values for B-Frames, GMC and such when invoking the codec on the segments of video?Yes.

[manono]

Hi-

I ran into the problem of different episodes compressing way differently with the Band Of Brothers DVDs. With those you also have the additional problem of each episode being a different length. If you have your heart set on putting each episode on it's own CD, then when you get those low percentages for some of them, there are some things you can do:
1. Use a softer resizer. If you're ordinarily using SharpBicubic or LanczosResize, then step down to NeutralBicubic.
2. Put on a Temporal Smoother, such as the Little Noise one in GKnot, or TemporalSoften (built into AviSynth 2.07), or TemporalCleaner (you'll have to download the .dll to use it as a Plugin).
3. Use a combo filter such as FluxSmooth or C3D (you'll have to download the .dlls to use them as a Plugins).
4. Give them lower quality audio to allow more bits for the video.

[goofy183]

That is pretty much my plan with the few episiodes that aren't very compressable. If all else I'll put em on 2 CDs but I'd rather not. I'm lucky and these are all one length, 44 minutes 13 seconds each, all extactly the same frame count.

How would I go about using some of the better noise filters? The ones included with GKnot seem to make my output have a "pastel" look ... if thats the correct description.



Oh and thank you both for helping me out with this, it's nice having the experiance of others to bank on.

[manono]

Hi-

To find out which filters are included with the AviSynth 2.07 included with GKnot, you can go here (http://www.avisynth.org/index.php?page=FiltersByCategory). But you are looking for the YUY2 ones and not the YV12 ones. For the built in ones, you only have to add a line to the .avs. As just one example:

TemporalSoften(3,5,7)

You might put that just before the Resize line.

For the 3rd party plugins to be found Here (http://www.avisynth.org/index.php?page=Section+3%3A+Filters+and+colorspaces#q3.3) (again, the YUY2 ones), you have to download the .dll, put it in the GKnot folder, and then load the plugin as well as add the line to your script. Another example:

LoadPlugin("E:\DIVXST~1\GKnot\TemporalCleaner.dll") #up near the top, by the other plugins.
TemporalCleaner() #usually just before the resize line.

If you think your colors are getting washed out, you can use the Tweak filter to saturate or brighten them up.

[wingphil]

when trying to get a whole series (or a set number of eps) of a tv show on one cd, i find it useful to make one d2v project out of all the eps, and encode as one big (3hr or whatever) file, then split afterwards. this ensures that they are all the same quality, and it doesn't matter if they are different lengths or compress by different amounts, the bits will be distributed accordingly.

edit: whoops, may have misunderstood your problem.