What's the logic behind IVTC of material with varying framerates?

[CursedLemon]

I posted a thread roughly six months ago about something related to this, now I wanted to ask it again more generally but with a bit more clarity.

If I have a DVD rip of source material that has 23.96 and 29.97 sections, what is the process I would use to transcode this rip into something like x265? Can this be done in one pass with a utility that can detect and adjust to the changing framerates and output a singular VFR file? Or is it actually necessary to perform a separate transcode for each section and then stitch them together, possibly via timecode somehow?

[manono]

Do you have a sample of what you're talking about? Do you mean a mix of hard and soft telecine? Or do you mean real interlaced or progressive 29.97fps plus some real 23.976fps content, either hard or soft telecined. Because that's pretty rare. Not impossible, but rare.

In any event, AviSynth's TFM can create the ability to help make VFR encodes. Read its included doc. No, you don't have to encode each section separately and then stich them together.

Here's a page on it, describing a couple of ways to create VFR MP4 or MKV:

http://avisynth.nl/index.php/VFR

[CursedLemon]

Do you have a sample of what you're talking about? Do you mean a mix of hard and soft telecine? Or do you mean real interlaced or progressive 29.97fps plus some real 23.976fps content, either hard or soft telecined. Because that's pretty rare. Not impossible, but rare.

In any event, AviSynth's TFM can create the ability to help make VFR encodes. Read its included doc. No, you don't have to encode each section separately and then stich them together.

Here's a page on it, describing a couple of ways to create VFR MP4 or MKV:

http://avisynth.nl/index.php/VFR

I assume it involves the former. The example I used previously involved ripping anime episodes from DVD, which have legit 29.97 sections (like intro/outro and some higher budget animation moments) scattered within footage that is normally 23.96. I don't know whether the material is hard or soft telecined. I know AnimeIVTC exists but I don't know exactly what it does.

[manono]

That's what I was afraid of - anime. Yes, they sometimes have true 29.97fps intros/outros and credits, and sometimes other stray sections, with a mostly 23.976fps episode.

AnimeIVTC can help, maybe. It seems to be capable of helping to create VFR MKVs.

[jagabo]

You could just encode at 59.94p.

[CursedLemon]

You could just encode at 59.94p.

Would that lead to any kind of weird garbagey interpolation/blurring problems?

[jagabo]

It will give you the same thing you see when you watch the original DVDs. But with better deinterlacing if you use QTGMC(), and a cleaner picture if you perform other cleanup.

[jagabo]

One way to make VFR with AviSynth is to use constant frame rate that's an intger multiple of all source frame rates. So for a mixed 23.976p and 29.97p source use 119.88 fps. Then use DeDup() to remove duplicate frames and build a timecode file. Finally, mux the timecode file with the encoded video.