Unofficial VirtualDub Support Forums [Powered by IB Forums]

Printable Version of Topic
Click here to view this topic in its original format

Unofficial VirtualDub Support Forums > VirtualDub Filters and Filter Development > Any Deblocking Filter?

Posted by: NuPogodi Apr 6 2004, 03:05 PM

Could anyone recommend deblocking filter (no matter, for VDub or for AviSynth) which is optimized to reduce 16x16-blocky artifacts? i've tried to use spatial denoisers (SmoothHiQ, PeachSmoother, etc). The results are dissappointing: appreciable increase in encoding time, nearly no improvement for blocky frames and too much blur for non-blocky ones. i've also tried to improve a situation by using AviSynth's DirectShowSource() post-processing... it looks better, but still too far from what i hoped to obtain.
Thanks, Alex

Posted by: Cyberman Apr 6 2004, 04:12 PM

Have you tried to upsize, smooth and downsize?
Also, what about the MSU deblocking filter - isn´t it good?

Posted by: NuPogodi Apr 6 2004, 04:23 PM

QUOTE (Cyberman @ Apr 6 2004, 10:12 AM)

Have you tried to upsize, smooth and downsize?
Also, what about the MSU deblocking filter - isn´t it good?

I've tested DancingBlocks and MSU Deblocking filters for VDub. The latter looks quite good in the preview window, but gave me nearly no profit in encoded material (i suspect this version is for demo purposes only).

Upsizing, smoothing & downsizing? well, it may probably help, but... upsizing will enlarge the block size, so filtering the artifacts will require to use smoothing procedure with VERY large radius. probably, too slow method for my old PC... but i'll try.

EDIT ! I apologize. MSU works, it is just not enough for this movie. I'll try to combine various filters, although the best choice would, probably, to search for better copy.

Posted by: Cyberman Apr 6 2004, 08:46 PM

QUOTE (NuPogodi @ Apr 6 2004, 05:23 PM)

Upsizing, smoothing & downsizing? well, it may probably help, but... upsizing will enlarge the block size, so filtering the artifacts will require to use smoothing procedure with VERY large radius.

Yes, that´s the point about it - the filter can go onto the video with brute force, and the downsize will (hopefully) smooth it out again.
A VERY slow procedure, but it often helps, at least, that´s my experience. Filters that would otherwise be too strong can be "softened" that way.
(Like the PCVideo Median Filter)

Posted by: dmitriy May 22 2004, 11:01 PM

QUOTE (NuPogodi @ Apr 6 2004, 10:23 AM)

This is not demo (see http://neuron2.net/ipw-web/bulletin/bb/viewtopic.php?t=391 )

Can you describe situation or change VD version?

Dm.

Posted by: NuPogodi May 24 2004, 07:56 AM

QUOTE (dmitriy @ May 22 2004, 05:01 PM)

This is not demo

I have already recognized that it is not a demo... your filter worked well on moving scenes, but was unable to remove blocks at static ones. Actually, the latters should not appear, but they are... Why? Somebody (with a lack of brains) used DIV3, low motion and, as i suggest, 1-pass CBR for video compression. Besides, the frame size was 640x480 (obviously, too large for ~800-900kbps DIV3)

Well... For reconstruction i've used several methods. At first, i've installed ffdshow, loaded this movie (btw, "Letyat zhuravli", 1957) via AviSynth's DirectShowSource and played with post-processing and noise reductions options. Then, i've tested several deblocking filters (both for AviSynth and VDub) with and without a combination with ffdshow. Results were also not too successful. The Cyberman's advice gave also not too much profit. Finally, i gave up!
There are no ways to make a sweet from a shit.

Posted by: TCmullet May 30 2004, 04:10 AM

QUOTE (Cyberman @ Apr 6 2004, 11:12 AM)

Have you tried to upsize, smooth and downsize?
Also, what about the MSU deblocking filter - isn´t it good?

Cyberman: I'm intrigued by your idea of resizing upward. Can you suggest values to use? For example, I've been capturing at 640x480, then resizing down to 480x480 or 352x480. What should I resize upward to??

For smoothing, I've been doing temporal smoother (setting 3) followed by 2d cleaner optimized (radius 1, strength 5 to 8). Can these both be done at the upsized stage with no problems? What smoothing do YOU use? (I'm going to try MSU denoiser again.)

Thanks for your insights.

Posted by: Cyberman May 30 2004, 08:28 AM

I´m usually just juggling numbers until the video looks better. So for resizing, I merely add a zero at the end - later trying to go down a bit.

I think it should work with any filter, but with temporal filters the problem is that they tend to to blur motion, so I hardly use one. As last step maybe, but very carefully. Unless there´s not much motion in the video.

Sometimes mere up and downsizing helps - using different algorithms like Lanczos3 for up, and Bicubic for downsizing.
The 2D cleaner I use quite often - sometimes the optimized, sometimes the normal version.

There´s not telling which numbers will work best - or at least I can´t tell. I simply try some numbers that seem to be good, save a bit of the video(200 frames or so) and watch it to see how good/bad it is.

Also, if you´re trying to clean up the video - I´d suggest copying the input/output frame to paint for comparison(using CTRL-1/2 in VDub) - paint can´t do much, but it provides a good zoom - two windows open at the same time allow easy switching for comparison.
Of course, you can´t compare motion then...

Posted by: TCmullet May 30 2004, 12:10 PM

QUOTE

So for resizing, I merely add a zero at the end - later trying to go down a bit.

Thanks, but I was hoping you'd give real numbers (yes, I can add a zero myself), because implicit in your answer would have been an answer to another question I didn't state, namely, what about the vertical? If we're dealing with interlaced video (of which everything meaningful is), isn't it dangerous to mess with the x480 dimension? In otherwords if I upsize from 640x480, should I always keep the 480 fixed, or can I upsize IT as well?

So adding a zero would make it 6400x480. What do you mean by trying to go down a bit? I know I'd take it down to 352x480 after noise reduction, but I got the impression you meant something else.

QUOTE

...and watch it to see how good/bad it is.

Can upsize/downsize make it worse? I was hoping to learn from y'alls experience, rather than spending hours and hours experimenting all over again. (Noise reduction experimentation is very painful what with poor tv/computer monitors I'm forced to use.)

QUOTE

The 2D cleaner I use quite often - sometimes the optimized, sometimes the normal version.

I remember the docs for the 'normal' said it worked better for feeding an mpeg compressor, but I've never been able to see it work any better than 2d-opt. So I've been using 2d-opt all the time (even though I'm always feeding mpeg). What circumstances would make you choose norm over opt?

I'm not trying to complicate things, but I really want your insights/experiences on these things. Thanks.

Posted by: Cyberman May 30 2004, 01:45 PM

I meant adding a zero on BOTH dimensions, of course.

Yes, the up/downsize can make it worse - after all, it does blur out detail, right? There shouldn´t be any decrease, though, but I wouldn´t bet on it.

Also, the x10 is just a value I use - surely a lower value(perhaps doubling the size) will do it as well - I´m just too lazy to rewrite the entire value.

Posted by: dmitriy May 30 2004, 04:28 PM

QUOTE

Our filter specially oriented on common 1-pass CBR. So if thare is no motion in scene - this will be detail's on frame (not blocking), like for video compressed with
1-pass CBR.

QUOTE

Well... For reconstruction i've used several methods. At first, i've installed ffdshow, loaded this movie (btw, "Letyat zhuravli", 1957) via AviSynth's DirectShowSource and played with post-processing and noise reductions options. Then, i've tested several deblocking filters (both for AviSynth and VDub) with and without a combination with ffdshow. Results were also not too successful. The Cyberman's advice gave also not too much profit. Finally, i gave up!
There are no ways to make a sweet from a shit.

Maybe this is possible, but very difficult.

Somebody said that it's possible to make bread from stones, and wine from water. But this is not simple task.