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Old 2nd January 2002, 11:30   #1  |  Link
ChristianHJW
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.. excellent work on file size reduction with temp smoother ..

Excellent work done by acaila :

http://www.divx.com/forums/viewtopic...=23495&forum=6
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Old 2nd January 2002, 12:22   #2  |  Link
yosemite
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but can u use these "smoother" settings in G-Knot too?

didnt find any register where I can make it

and now in german:
Kann man auch irgendwo in G-Knot einstellen?
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Old 2nd January 2002, 14:11   #3  |  Link
Acaila
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Wow, thanks for spreading my work around ChristianHJW

As for Yosemite's question, all you need to do is open the .avs file generated by GKnot with a text editor (or change the extension to .txt) and change "TemporalSmoother(2,1)" to "TemporalSmoother(3)" or (4) or whichever is your preference.
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Old 2nd January 2002, 14:21   #4  |  Link
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well... I can't quite agree with "smoothing doesn't reduce crispness".. every time I used any smoother filter I know of I could tell the difference... and divx4 already smoothes the picture a bit too much for my taste without any additional filters. To be perfectly honest.. from a crispness point of view divx3 is superior to divx4. If I get blocks.. I don't use a smoother, I reduce the resolution because the former is much more visible.
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Old 2nd January 2002, 14:53   #5  |  Link
Acaila
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Temporal Smoother works between frames unlike normal smoothers/cleaner which work inside frames and as such has a much less visible effect on crispness. Using it before resizing results in an even further decrease on visible effect.
I think it's a great way to reduce total filesize with as little effect on crispness as possible, but that's what everyone has to decide for him/herself.
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Old 2nd January 2002, 15:52   #6  |  Link
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I agree with Doom9 , i'm waiting for Xvid development, hoping a better post-filter than Divx4 and a real coherent 2 pass, hello Blacksun!
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Old 2nd January 2002, 20:15   #7  |  Link
MaTTeR
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ChristianHJW,

Thanks so much for posting this link. I gotta try this :-)

@Acaila-
Great work and testing. Thx alot!
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Old 3rd January 2002, 12:51   #8  |  Link
ChristianHJW
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... the key here is to use the filter before resizing .... TheWEV made me a very happy man by adding this feature as a standard into GKNot .

Yes, there is a loss of crispness, but when resizing to normal resolutions for 1 CD rips ( and this is what its ment for, i never use filtering for 2 CD rips ) like 560 * 240 ... 608 * 256 the effect is only marginal, even smaller than using a different resizing filter, but will give better file size reduction overall.
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Old 3rd January 2002, 18:27   #9  |  Link
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...and I'm not sure the effect of smoother filter was so bad for 2 CD rips.

I've done a 2CD rip of Proof Of Life at 640x256 tempsmoother(1) and I'm very pleased, the overall quality is really great I doubt it could be so great without the filter. But it's only an opinion.

I'm doing 2 encodings of 2CD from "Dr. T." I want to see how the subjective is the opinion of doom9 about using lower resolution instead use a filter.

First 2 CD rip is 640x256 TempSmoother(1)
Second 2 CD rip is 608x240
Duration 1:55 min aprox || Audio 120Mbytes, 145kpbs VBR mp3 audio.

In the first rip without tempSmoother(1) compresibility was about 65% I think this value isn't enough for me. Obviously if it was something like 75% I wouldn't use any filter.

Well tonight I finish the 10hours First rip and tomorrow the second rip. If someone is interested I could attach images of both encondings, when they finish.
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Old 3rd January 2002, 19:19   #10  |  Link
Acaila
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Quote:
If someone is interested I could attach images of both encondings, when they finish.
I am
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Old 3rd January 2002, 19:29   #11  |  Link
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I can see how smoothing might help with a noisy source.

But if you have a clean source, aren't you just creating ghosting??

I don't buy it. Has anyone compared the compressibility of something with and without temporal smoothing? Assuming noise is out of the picture, isn't it unclear what the relationship between the amount of smoothing and the compressibility is?

I think an interesting experiment related to temporal smoothing would be to interpolate the motion vectors between resulting mpeg-4 frames to generate in-between frames. You could use bilinear, trilinear, or any interpolation algorithm really. The question is whether you end up with more perceived detail and better pans. Of course this is useful only for folks with high refresh rate display devices.

Edit:

I just realized that in many dvd's you can see evidence of film grain. I can see how tempsmoothing (w or w/o resizing) definitely would help with that.

Last edited by b0b0b0b; 3rd January 2002 at 19:32.
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Old 3rd January 2002, 21:52   #12  |  Link
Acaila
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If you have a noisy sourse then temporal smoother would have less of an effect than normal in-picture smoothing.
The trick with TempSmoother is that it reduces the difference between one frame and the adjacent ones, and since compression relies on storing differences only, it reduces file size. Using low enough settings will make it easier on the codec, but will keep visible distortions minimal.

Btw, my test was on a DVD source, so it was clean to begin with and still gave nice size reductions.
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Old 4th January 2002, 00:20   #13  |  Link
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Re:

Quote:
Originally posted by Acaila
If you have a noisy sourse then temporal smoother would have less of an effect than normal in-picture smoothing.
The trick with TempSmoother is that it reduces the difference between one frame and the adjacent ones, and since compression relies on storing differences only, it reduces file size. Using low enough settings will make it easier on the codec, but will keep visible distortions minimal.

Btw, my test was on a DVD source, so it was clean to begin with and still gave nice size reductions.
I read your post on the link given by ChristianHJW.
Interesting but i'm not sure it's possible to interpolate from a test with a bitrate of 6000 ...
In fact i'm sure that the percentage with a lower bitrate (for one CD rip) will be different..
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Old 4th January 2002, 01:37   #14  |  Link
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I'm totally agree with acaila, in some tests I did when I encoded movies the increase in compresibility with the filter depends of the movie.

With the little noise filter in Gordian Knot (it has less effect than tempsmoother(1) I think is like tempsmoother(0.5)) the compresibility increase is between 3-6%.
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Old 4th January 2002, 01:57   #15  |  Link
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What about BilinearResize + TemporalSmoother(2,1) ?

I tested it on noisy DVDs, it make miracles, the picture looks so calm, natural and beautiful (I would call it, a charming picture ). The loss in sharpness is unnoticeable, unless one compares directly the DVD-Picture and the DivX4-picture.

@ Christian
Why do you propose to use temporalsmoother before resizing?! I can't see the advantage of that technique.
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Old 4th January 2002, 10:09   #16  |  Link
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Quote:
I read your post on the link given by ChristianHJW.
Interesting but i'm not sure it's possible to interpolate from a test with a bitrate of 6000 ...
In fact i'm sure that the percentage with a lower bitrate (for one CD rip) will be different..
Ofcourse the percentage will be different. The amount of size reduction is highly dependent on the type of movie scene and general noise too. With a lower bitrate you'll get more noise, and compression will increase. These percentages were only given as a guideline, not absolutes, to show that compression increased with higher settings and adequate compression increase can be achieved with minimal visible effect on crispness.
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Old 4th January 2002, 16:59   #17  |  Link
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Well I have finished my temporalsmoohter(1) rip, now I'm waiting for the 608xXXX and 576xXXX rip. BTW I have redone the compresibility check at 7% and it's 60% with 640x... without filter and with temporalsmoother(2,1) it's 69% (I'm surprised because the first minutes of the movie are very noise, in compresibility check it arrives to 500K) and the correct duration is 1:52

I've done some proves with constant quality 100% with temporalSmoother(1) and lowering the resolution and...

Being objective...yes, the image is more sharpness with 576x240 than with 640x256 with TempSmoother(1). But it hasn't better overall quality.

The image loss sharpness at noisy parts, like human skin (faces) and specially when those noisy parts are moving, faces of human skin moving, again. But the overall quality isn't better lowering resolution. And the differences are very subtle I'm very near of my 17" monitor.

However images without persons are really good.

More information on aprox. 1000 frames(I have more results but are about the same):

CQ 100% 15Mb 640x256
CQ 100% 12.6Mb 576x240
CQ 100% 11.7Mb 640x256 TS(1)

I'm waiting the encoder finish the job, but I think in those cases there isn't enough space and lowering the resolution to 576 isn't enough. I've seen some scenes of the rip ts(1) and there is a smooth effect in a wall but it's like the encoder hasn't enough bits to do it well and not like a temp smoother effect.

IMHO I think below 70% at 640x256 2 CD rips you could use tempsmoother(2,1) and the overall quality should be better(not faces but overall quality and faces weren't so bad). Or at least it's not as easy as lowering resolution.

Well like I said I'm waiting the results of the 2 and 3 rip before obtain a conclusion but, I think lowering resolution is good when 2CD were good enough not like this case when Ts(1) has less size than 576.

What are your opinions?
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Old 4th January 2002, 20:40   #18  |  Link
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Well I just ripped 3 different movies with my temporal setting @ 3. All were encoded for 1CD with audio averaging 128k and resolutions @ 560. All I can say is wow! Very big difference in quality indeed. The overall PQ (picture quality) was much better than the previous rips when I was just using the generic "Little Noise" selection in Gknot.

I really didn't notice any loss of definition using the filter but maybe it's just my eyes. Thanks so much guys for this great tip.

BTW- What about using a temporal setting of 2 when I encode amovie for 2 CD's? Would this have any effect?
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Old 4th January 2002, 21:19   #19  |  Link
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Do you guys watch these movies on a TV or on a computer screen. If on a computer screen, do you blow it up to at least 1280x1024 on a 21"?

Just trying to get a feel for how you are gauging PQ.
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Old 4th January 2002, 21:52   #20  |  Link
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Re:

Quote:
Originally posted by b0b0b0b
Do you guys watch these movies on a TV or on a computer screen. If on a computer screen, do you blow it up to at least 1280x1024 on a 21"?
I only watch mine on a 27" Tube TV @ 800x600 resolution. This obviously isn't optimal of course but I don't have the moolah for HDTV. This is how I judge my PQ. Watching it on a monitor is much less forgiving due to dot pitch & resolution.
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