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Old 30th April 2010, 16:47   #1  |  Link
aegisofrime
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Deinterlacing Workflow Guides

Hi, I'm looking for advice on the order in which I should use various filters.

Let's assume my source is good. Not overly noisy or crappy framerate conversions or anything like that.

My current workflow is thus, in plain English:

Load Video using DGDecode
TempGaussMC
Encode with x264 --crf 23 --preset "Slower"

My objective is to backup my DVDs, deinterlacing them with TGMC for smoother viewing while keeping file size low. It's a pain to be swapping discs. I like to keep the rips on an external hard drive for convenience

Now, I'm wondering if there's anyway to improve my current workflow. Would adding FFT3DFilter(interlaced=true) before TempGaussMC help compressibility? I know denoising kills details, but I don't want it to kill TOO much detail.

Thanks for your help!
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Old 30th April 2010, 17:00   #2  |  Link
Inspector.Gadget
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The problem with asking for general recommendations is that Avisynth filter combinations are generally only suitable for specific cases.
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Old 1st May 2010, 02:07   #3  |  Link
manono
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And most DVDs don't need and shouldn't be deinterlaced. If PAL movies, they may need the fields realigned or to be unblended (both pretty rare). If NTSC movies, they may need an IVTC or (rarely) unblending. You'd just be wasting computer cycles and, in some cases, seriously degrading the result. And what's the point of doubling the frame rate?
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Old 2nd May 2010, 22:03   #4  |  Link
Mystery Keeper
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Quote:
Originally Posted by manono View Post
And most DVDs don't need and shouldn't be deinterlaced. If PAL movies, they may need the fields realigned or to be unblended (both pretty rare). If NTSC movies, they may need an IVTC or (rarely) unblending. You'd just be wasting computer cycles and, in some cases, seriously degrading the result. And what's the point of doubling the frame rate?
Disagree. It is true that most of frames in NTSC DVDs are progressive after IVTC. But somehow some of them are still interlaced. Often happens on scene changes. Also, Japanese DVDs tend to have sequences with every 4th frame having local interlacing. No matter what causes it, the problem remains. DVDs need to be deinterlaced even after IVTC.
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Old 2nd May 2010, 23:14   #5  |  Link
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Quote:
Originally Posted by Mystery Keeper View Post
Disagree. It is true that most of frames in NTSC DVDs are progressive after IVTC. But somehow some of them are still interlaced. Often happens on scene changes. Also, Japanese DVDs tend to have sequences with every 4th frame having local interlacing. No matter what causes it, the problem remains. DVDs need to be deinterlaced even after IVTC.
In that case you really should use something that can work as a post-processor for IVTC and only deinterlaces frames that have still have some combing (e.g. TDeint).

Also if you have something that is Telecined and mostly has progressive frames after the IVTC (with only a few combed frames left), I certainly wouldn't bob that to the double framerate.
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Old 3rd May 2010, 09:20   #6  |  Link
manono
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Originally Posted by Mystery Keeper View Post
DVDs need to be deinterlaced even after IVTC.
There are only a very few cases where you'll need a conditional deinterlacer (TDeint(Full=False), Vinverse) after an IVTC, especially since they already have post-processing built in by default. In more cases like that an IVTC isn't called for in the first place (blended sources). If you have any examples handy, I'm sure we'd be happy to have a look.

Anyway, the OP wasn't talking about using an IVTC at all, but a pure double-rate deinterlacer for all cases. I stand by my statement.
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Old 3rd May 2010, 12:53   #7  |  Link
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Anyway, the OP wasn't talking about using an IVTC at all, but a pure double-rate deinterlacer for all cases.
So the OP needs to understand that in the real world there isn't "the one" method that works well for everything

As you said already, most DVD's are either progressive or Telecined, so a proper IVTC should be sufficient in most cases. Deinterlacing most likely destroys quality for no benefit.
Bobbing (i.e. doubling the frame-rate) of progressive/Telecined footage is even worse than "same rate" deinterlacing, as it produces lots of redundant data and thus hurts quality even more after compression.
Anyway, blindly IVTC'ing everything isn't a solution either. In the rare case of "true interlaced" footage on DVD (as seen on "concert" discs), a deinterlacer (preferably a good bobber) will be required.

Conclusion: The only thing that can be suggested in general is that one has to analyze the individual disc before deciding the proper way to deal with it...

Quote:
Would adding FFT3DFilter(interlaced=true) before TempGaussMC help compressibility?
TempGaussMC already removes noise/grain to some degree!

If at all, you could use FFT3DFilter to remove the noise before TempGaussMC and re-add the noise afterwards:
http://forum.doom9.org/showpost.php?...44&postcount=7
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Last edited by LoRd_MuldeR; 3rd May 2010 at 13:54.
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Old 3rd May 2010, 14:51   #8  |  Link
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If at all, you could use FFT3DFilter to remove the noise before TempGaussMC and re-add the noise afterwards:
or use lossless mode.
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Old 5th May 2010, 14:04   #9  |  Link
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Originally Posted by Mystery Keeper View Post
Disagree. It is true that most of frames in NTSC DVDs are progressive after IVTC. But somehow some of them are still interlaced. Often happens on scene changes...
Question: is that why DGIndex says 99% film instead of 100%?
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Old 5th May 2010, 14:29   #10  |  Link
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Question: is that why DGIndex says 99% film instead of 100%?
No, that's dictated by pulldown flagging. Quite often in the 99% scenario, the movie itself is all film with pulldown but the credits/intro are flagged as interlaced. Whether they are actually interlaced or not is something you can only find out with your eyes, but since there are so many black frames anyway, often it's difficult to tell (and forcing film often won't create any noticeable problems).
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