Deinterlacing in Premiere

[Nikolaj Marquez von Hage]

OK Robert, now I'm confused. After reading some of "New Edge-Directed Interpolation" I can only conclude that this is a technique for image interpolation. That's great for what I was asking for in another thread (upscaling from SD to HD, for example) but it has not got to do directly with deinterlacing.

BTW, you don't happen to know some free implementation of Xin Li's method?

Regards,
Nikolaj

[Nikolaj Marquez von Hage]

I understand that sometimes one may want to turn 60i to 60p, in sports for example, and then one has to use bob filters and interpolate from one field and the like. But for deinterlacing from 50i to 25p, as in my case, image interpolation is not relevant. Not directly, at least.

[Robert Martens]

I suppose I could have done a better job of explaining this, let me try it a different way.

The "NNEDI" I mentioned as part of the enlarging process in that other thread (Neural New Edge-Directed Interpolation, I believe) is, in fact, a deinterlacer. It uses NEDI techniques as part of what it does; throwing away half of the fields produces frames with missing information, that are then interpolated (via NEDI) back to full height. The theory itself may not seem to apply directly to deinterlacing, but when applied in this fashion proves quite able.

This software, mind you, is NOT applied by itself in the TempGaussMC script. One of the fundamental aspects of Avisynth is the scripting language. Scripts can get very complicated, involving the creation of your own functions, and that's exactly what's happened in TGMC: the output of the NNEDI plugin is being manipulated to produce better results. The NNEDI plugin is useful in its own right when run as the only filter on an interlaced input file, but in this case is only one of many, many things being done by TempGaussMC.

Follow me back to the other thread and I can show you how to use that script just for deinterlacing footage.

[Nikolaj Marquez von Hage]

Robert, let my quote you:

"Calling the deinterlacer is as simple as you see here, with the one change that we use NNEDI instead of the default EEDI2. I get the best results with that, though if you want to try the other options feel free.

TGMC is a bob deinterlacer, however, which means it turns fields into frames. You'll have 50 frames per second after it's finished, and since your project is 25p, the SelectEven() filter will grab every other frame and give you that. There's also a SelectOdd(), but since frames in Avisynth are numbered starting from zero, SelectEven will give you every other frame starting from the very first one."

Now, I'm really glad that you shared your workflow for upscaling with me. But: after reading more closely, it hit me that, according to the above, the method you describe is basically throwing one field away instead of using it for information. Now, what is my problem with that?
Well, my argument is this: except for the purpose of doubling the frame rate, one should always try to combine the two fields. Why? Because with 25 images per second (in my case) motion may become more "stroboscopic" if just using one field due to the shorter shutter time. Combining the two fields (which blending does) gives some "motion blur" automatically. This removes the "stroboscopic" effect.

I realize that tastes may vary. But the idea is that ideally, if a movie/film/moving image
is presented at n images per second, then the shutter speed for every image at capture should be 1/n of a second, so as to give a full temporal representation of the motif.typo

[Robert Martens]

For what it's worth, the SelectEven() filter is called after deinterlacing is complete. It throws away frames that are the result of interpolation, and has no effect on the calculation of the progressive frames in the first place. You can see exactly how all of this is done by opening TempGaussMC_beta1.avs in Notepad and reading the various functions. From the sound of it you'd get more out of the technical info laid out there than I ever could.

You may be correct; I'm really not sure TGMC does anything at all about motion blur (though I could very easily be wrong). You seem to know more about this than I do, I just wanted to share my particular workflow. Keep in mind, TempGaussMC is only something I use to prepare clips for resizing. The Lanczos4Resize is what does all the work, and is still useful even if you don't like the way I do things.

To resize without deinterlacing, try deleting everything in the script I gave you after the AVISource line and pasting in this instead:

AssumeBFF()
SeparateFields()
Lanczos4Resize(1440,540,0,36,720,216)
Weave()

You even get to avoid the YV12 conversion. This script will separate the fields, resize them by themselves, and then re-interlace them so that you can deinterlace the result yourself using whatever method you prefer.

Or, of course, you can still deinterlace before the scale, using any number of third party options: http://avisynth.org/mediawiki/Extern...#Deinterlacing

[Nikolaj Marquez von Hage]

Wow, the number of options is certainly overwhelming! AviSynth seems to be really fun, I'll definitely explore it and its plugins more from now on. Thanks Robert for all your input, I have more than enough now to play and tweak with until I find a workflow that suits me.

And then again, it is really tempting to just save some money and invest in a Panasonic P2 camera with 1080/25p recording mode, combined with Prospect HD for post... but where's the fun without all the tweaks?

[Robert Martens]

You're very welcome! Avisynth is a lot of fun to play with, and I think you're right:

Originally Posted by Nikolaj Marquez von Hage

And then again, it is really tempting to just save some money and invest in a Panasonic P2 camera with 1080/25p recording mode, combined with Prospect HD for post... but where's the fun without all the tweaks?

If it weren't for all the deinterlacing, color conversions and scaling, I'd be bored out of my mind. Footage that comes out of a camera the way you want it? Where's the fun in that?

[Tripp Woelfel]

Originally Posted by Nikolaj Marquez von Hage

Tripp and Robert, I have to point out, just for the record, that field blending DOES make the jaggies disappear. It's not motion blur applied on jaggies.

Reality wins over perceived logic every time. I appreciate this discussion. There's lots to learn here.

[Mike McCarthy]

So after some simple tests, I have determined that Premiere CS3's deinterlace export option throws away the second field, and fills in the missing data by blending the lines above and below at 50% each. Be advised that using this method throws away 50% of the image data right off the top, before compression.

[Nikolaj Marquez von Hage]

It seems you are right. I did some tests on my Premiere 2.0 and they confirm your tests.

[J.J. Kim]

Originally Posted by Mike McCarthy

Where are the deinterlace options in CS4? I usually use CS3 at work, but only have CS4 on my system at home. Unless I find those options on CS4, I will put off the test until I have a CS3 system available next week.

I have done each clips by right click-field option-always deinterlace...
When I export my videos to h.264 to post on vimeo and smugmug, I have to deinterlace everything (even though I shot everything in 30p) because when the clip has slow mo OR text animation from AE has those annoying lines...
I know there is "progressive" export in some preset for certain video types, but how about quicktime or h.264 output? How are we supposed to deinterlace those if the sequence contained more than 100 different clips???
I don't understand why Adobe take away a one simple option on Media Encoder to make it messy like that.

[Ray Bell]

Does this review of twixtor and fieldskit help

Marco Solorio reviews: RE:Vision Effects, ReelSmart Twixtor with FieldsKit Deinterlacer : Adobe After Effects