Inverse Telecine and Me

[JiiSune]

I'm using the guide from: http://www.doom9.org/index.html?/divx-encoding.htm (the one on XviD: http://www.doom9.org/xvid.htm) and actually did very well encoding my own movies. I tried two and then one anime but my anime one came out with alot of sort of 'scan lines' when the characters were in motion. Someone suggested Inverse Telecine, although I'm not sure what that is. Can anyone link me to information regarding this subject/technique and how I can apply it to my encodes? And any anime encoding techniques would be greatly appreciated.

[jellysandwich]

Here's a very good guide for newbies:

http://www.doom9.org/ivtc-tut.htm

js

[manono]

Hi-

Although that tutorial will give you the basics, the software used for this has changed since it was written. For example, DVD2AVI has evolved into DGIndex. No longer (when planning to use IVTC) do you make the Project File with no Field Operation, but with Honor Pulldown Flags (both are 29.97fps when opened in GKnot). And the IVTC settings have also changed, but GKnot will take care of that for you upon checking the IVTC box.

A lot of anime is quite difficult to encode properly, but for most of the TV episode DVDs being converted to AVI, IVTC is a must. However, sometimes you get a mix of 23.976fps and 29.97fps within the same anime (the notorious hybrids), and a regular IVTC might not work so well on some of it (the 29.97fps parts). If you haven't yet, you might also consider giving AutoGK a try, as it can figure out these sometimes difficult things automatically. For anime, especially, you often have to examine your source carefully, in order to figure out just how to handle it. And if you're not quite sure just how to do that yet, AutoGK can save you a lot of headaches. But maybe you're working on a relatively easy project. If you give us the names of some of your anime, maybe some people around here have already encoded them, and might have some tips to offer.

[JiiSune]

In what ways do you mean examine my source? And although I may have simply overlooked this (I apologize if so) but I noticed in Gordian Knot I'm unable to select the exact resolution I want. I can use the slider to select resolutions of course but I can't type in the exact properties in either fields. How can I set my resolution to the exact height and width I prefer?

[manono]

Hi-

In what ways do you mean examine my source?

I mean you have to determine what you have. Some are blended. Some are hybrid. Some are straight telecined. You have to figure out if it can be IVTC'd and with what settings.

How can I set my resolution to the exact height and width I prefer?

Well, you can always edit the .avs pretty easily, if you prefer to do it wrong. As an example, if it says:

LanczosResize(640,464), you can just change the 464 to 480.

Another way to get it to give you resolutions that may be more to your liking is to go into the Options Tab, and either check or uncheck the "Follow ITU..." box.

If you have either 16:9 (default) or 4:3 correctly ticked up at the top of the Resolution Tab, and crop to get a low Aspect Error, then GKnot does it right, and you shouldn't have to change the resize it gives you. Can you give me an example of what you had in mind?

[JiiSune]

Ah I see what you mean. Is there an updated guide on methods to accurately uncover the type of video I'm working with? And I didn't mean alter the settings for resolution as to destroy the video just wanted a solid 640x480 for instance instead of 640x464. But I'll just edit the script as you instructed thank you very much.

[manono]

I think that unchecking the ITU box as described previously will give you 640x480. Then you shouldn't have to edit the .avs.

As for an updated guide, well, that guide is still valid as far as determining what kind of video it is. You open the 29.97fps D2V in GKnot and find a place with movement. Look for the 5 frame pattern of 3 clean progressive frames followed by 2 interlaced frames. That's evidence of it having been telecined to 29.97fps, which can then be IVTC'd. Check that in several places. Take particular care to check the opening song and the end credits. Sometimes the opening songs can be 30fps progressive (GITS-SAC, for example), and sometimes the end credits are 30fps interlaced (Cowboy Bebop, for example). If you find that at the beginning or the end or elsewhere, that's when you have to adjust the standard IVTC settings.

Again, you might give AutoGK a try, as it can detect these things itself, and might give better results than you might get yourself until you get the hang of it.

[JiiSune]

Thank you very, very much.

[manono]

You're welcome.

Anime is perhaps the toughest kind of video to work with. If you're the kind that jumped into the deep end of the pool before you knew how to swim, then it's for you. The anime movies are usually (but not always) OK, and can be Force FILM'd easily to 23.976fps. The TV series DVDs can be real tough sometimes, frustrating even very experienced encoders and AviSynth users. Good luck.