What type of issue is this?

Akai-Shuichi · 27th June 2012, 20:57

http://www.sendspace.com/file/qhmozg

here is a clip...look on the left shirt, at first I thought it was color banding, but I'm not quite sure now...and what filters would be effective against it?

atra dies · 28th June 2012, 02:53

Are you talking about seeing blocks? This is called blocking and could be caused by low bitrate mkv if you reencoded it for this sample. I hate it and when I tried to fix something like that I finally gave up and deleted it. But before that I was using the ultra slow (then, it's very fast now) mode 2 for gradun3. Something like this:

Code:

gradfun3(thr=.66,mode=2)

that could be destructive to fine gradients though but the default wouldn't smooth it. Maybe use the mask option.

Or I would use the smoothing in smoothlevels, and you can do it in 16 bits if you use:

Code:

smoothlevels16(smooth=50)

or whatever you want to smooth it with.

Usually people use deblockers but I don't think the result looks good and they smooth things that you don't want smoothed making it blurry.

Akai-Shuichi · 28th June 2012, 03:13

I have it set to CRF17 x264 so it shouldn't be low bitrate i'd think...but i'll try out those 2 filters

atra dies · 28th June 2012, 05:16

Oops that's

Code:

gradfun3(thr=.66,smode=2)

and it's still slow but I didn't mess with any of the parameters. You could probably speed it up.

I'd look into deblockers too like deblock_qed or CPU= for dgindex if using that cause in that screen grab you posted in the other thread there were mpeg artifacts around the letters. I had one with bad compression artifacts and just used mdegrain and that smoothed a little but I think players and/or TVs smooth these things out too when they resize. Look at anime page for blocking too like
http://www.animemusicvideos.org/guid....html#blocking
http://www.aquilinestudios.org/avsfi...patiotemp.html

Those pages are kind of old though.

I only process live action stuff though so maybe someone else has better advice.

Didée · 28th June 2012, 09:29

It's a temporal artifact: chroma ghosting. Seems like some very light temporal filter has been used at some point.

At least at one scene, I saw something that looks remotely like "inverse" ghosting, which makes it difficult to suggest any "correct" solution to the problem.
Maybe the whole shebang can be planished by using another temporal filter with very low threshold, like temporalsoften(5,4,4,16,2), or something like that.

Akai-Shuichi · 28th June 2012, 21:06

I've tried temporalsoften, but it doesn't seem to do anything. If I posted my avisynth script would that help any?

Though I think its like that from the source and I am starting to believe that there is not even a way to fix this issue.

27th June 2012, 20:57	#1 \| Link
Akai-Shuichi n00biest n00b Join Date: Jul 2007 Posts: 37	What type of issue is this? http://www.sendspace.com/file/qhmozg here is a clip...look on the left shirt, at first I thought it was color banding, but I'm not quite sure now...and what filters would be effective against it?

28th June 2012, 02:53	#2 \| Link
atra dies Registered User Join Date: Jul 2011 Posts: 32	Are you talking about seeing blocks? This is called blocking and could be caused by low bitrate mkv if you reencoded it for this sample. I hate it and when I tried to fix something like that I finally gave up and deleted it. But before that I was using the ultra slow (then, it's very fast now) mode 2 for gradun3. Something like this: Code: gradfun3(thr=.66,mode=2) that could be destructive to fine gradients though but the default wouldn't smooth it. Maybe use the mask option. Or I would use the smoothing in smoothlevels, and you can do it in 16 bits if you use: Code: smoothlevels16(smooth=50) or whatever you want to smooth it with. Usually people use deblockers but I don't think the result looks good and they smooth things that you don't want smoothed making it blurry.

28th June 2012, 05:16	#4 \| Link
atra dies Registered User Join Date: Jul 2011 Posts: 32	Oops that's Code: gradfun3(thr=.66,smode=2) and it's still slow but I didn't mess with any of the parameters. You could probably speed it up. I'd look into deblockers too like deblock_qed or CPU= for dgindex if using that cause in that screen grab you posted in the other thread there were mpeg artifacts around the letters. I had one with bad compression artifacts and just used mdegrain and that smoothed a little but I think players and/or TVs smooth these things out too when they resize. Look at anime page for blocking too like http://www.animemusicvideos.org/guid....html#blocking http://www.aquilinestudios.org/avsfi...patiotemp.html Those pages are kind of old though. I only process live action stuff though so maybe someone else has better advice. Last edited by atra dies; 28th June 2012 at 05:18.

28th June 2012, 09:29	#5 \| Link
Didée Registered User Join Date: Apr 2002 Location: Germany Posts: 5,407	It's a temporal artifact: chroma ghosting. Seems like some very light temporal filter has been used at some point. At least at one scene, I saw something that looks remotely like "inverse" ghosting, which makes it difficult to suggest any "correct" solution to the problem. Maybe the whole shebang can be planished by using another temporal filter with very low threshold, like temporalsoften(5,4,4,16,2), or something like that. __________________ - We´re at the beginning of the end of mankind´s childhood - My little flickr gallery. (Yes indeed, I do have hobbies other than digital video!)

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28th June 2012, 03:13	#3 \| Link
Akai-Shuichi n00biest n00b Join Date: Jul 2007 Posts: 37	I have it set to CRF17 x264 so it shouldn't be low bitrate i'd think...but i'll try out those 2 filters

28th June 2012, 21:06	#6 \| Link
Akai-Shuichi n00biest n00b Join Date: Jul 2007 Posts: 37	I've tried temporalsoften, but it doesn't seem to do anything. If I posted my avisynth script would that help any? Though I think its like that from the source and I am starting to believe that there is not even a way to fix this issue.