What to do with interlace artifacts left after IVTC (24p in 50i)?

Maxiuca · 11th July 2009, 00:42

I've got a 50i MPEG2 stream that was made directly from 24p source (so it wasn't speed up to 25 fps like it should have been, but instead encoded as 24p in 50i with all that interlacing and field doubling)
I've recovered the progressive frames using SeparateFields().DoubleWeave().SelectEvery(25,1,3,5,7,9,11,13,15,17,19,21,23) but the resulting frames still have some interlacing "artifacts" left (parts of the image appear to be still interlaced). Since this interlacing parts seem to appear in blocks I assume they were caused by MPEG2 compression which does not handle interlaced stream well.

Is there a way (filter or some smart script) to remove those artifacts?

Guest · 11th July 2009, 00:58

Quote:

Originally Posted by Maxiuca

What to do?

Post a link to an unprocessed source sample.

Maxiuca · 11th July 2009, 12:14

right, sorry, here is the sample
http://maxiuca.com/part.rar

It is a short sample, but it shows the problem. Please keep in mind that the quality is really bad. It's a 2.35:1 ratio image in a 4:3 PAL frame and the encode is also bad.

Anyway applying SeparateFields().DoubleWeave().SelectEvery(25,0,2,4,6,9,11,13,15,17,19,21,23) recovers the progressive frames. But if you go for example to frame 77 (after recovering progressive frames) you'll notice a lot of "mice teeth" left in some parts of the image.

Didée · 11th July 2009, 12:52

There is the Vinverse() script/plugin. It was made with exactly these kind of artifacts in mind.
It's listed on http://avisynth.org/mediawiki/External_filters

Maxiuca · 11th July 2009, 14:30

Wow, it's amazing, works like charm on default settings.

No I just need something for the chroma noise/artifacts. cnr2 maybe? But I've noticed cnr2 produces ghosting artifacts and when you lower the settings to get rig of the artifacts then it no longer denoises.

thewebchat · 12th July 2009, 02:50

On the sample you posted, MVDeGrain completely removes the chroma noise in the sample at the default strength. Also, to fix the PAL "telecine", you can do TFM.TDecimate(cycle=25).

11th July 2009, 00:42	#1 \| Link
Maxiuca Registered User Join Date: Dec 2002 Location: Los Angeles Posts: 92	What to do with interlace artifacts left after IVTC (24p in 50i)? I've got a 50i MPEG2 stream that was made directly from 24p source (so it wasn't speed up to 25 fps like it should have been, but instead encoded as 24p in 50i with all that interlacing and field doubling) I've recovered the progressive frames using SeparateFields().DoubleWeave().SelectEvery(25,1,3,5,7,9,11,13,15,17,19,21,23) but the resulting frames still have some interlacing "artifacts" left (parts of the image appear to be still interlaced). Since this interlacing parts seem to appear in blocks I assume they were caused by MPEG2 compression which does not handle interlaced stream well. Is there a way (filter or some smart script) to remove those artifacts?

11th July 2009, 12:52	#4 \| Link
Didée Registered User Join Date: Apr 2002 Location: Germany Posts: 5,391	There is the Vinverse() script/plugin. It was made with exactly these kind of artifacts in mind. It's listed on http://avisynth.org/mediawiki/External_filters __________________ - 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!) Last edited by Guest; 11th July 2009 at 14:15. Reason: fix URL

11th July 2009, 14:30	#5 \| Link
Maxiuca Registered User Join Date: Dec 2002 Location: Los Angeles Posts: 92	Wow, it's amazing, works like charm on default settings. No I just need something for the chroma noise/artifacts. cnr2 maybe? But I've noticed cnr2 produces ghosting artifacts and when you lower the settings to get rig of the artifacts then it no longer denoises. Last edited by Maxiuca; 11th July 2009 at 14:56.

11th July 2009, 12:14	#3 \| Link
Maxiuca Registered User Join Date: Dec 2002 Location: Los Angeles Posts: 92	right, sorry, here is the sample http://maxiuca.com/part.rar It is a short sample, but it shows the problem. Please keep in mind that the quality is really bad. It's a 2.35:1 ratio image in a 4:3 PAL frame and the encode is also bad. Anyway applying SeparateFields().DoubleWeave().SelectEvery(25,0,2,4,6,9,11,13,15,17,19,21,23) recovers the progressive frames. But if you go for example to frame 77 (after recovering progressive frames) you'll notice a lot of "mice teeth" left in some parts of the image.

12th July 2009, 02:50	#6 \| Link
thewebchat Advanced Blogging Join Date: May 2009 Posts: 480	On the sample you posted, MVDeGrain completely removes the chroma noise in the sample at the default strength. Also, to fix the PAL "telecine", you can do TFM.TDecimate(cycle=25).