How to add pulldown flags to a clip of mixed film/video?

[Mizkreant]

I recently captured a clip from a talk show from my cable STB to my Theater 550 capture card. The clip is mostly interlaced NTSC video with a short film clip that is 3:2 telecined. I originally captured to AVI using HuffYUV and then converted it to MPEG2. If I play back the clip using a decoder that supports hardware acceleration, my Radeon X1950 Pro (using AVIVO) seems to deinterlace the video portion fine, and seems to correctly detect the cadence of the film portion as well. How can I tell for sure that my hardware is correctly applying 3:2 pulldown or if it's just deinterlacing it?

Also, just out of curiosity I was wondering if there's some way to apply 3:2 pulldown to restore the frames of the film portion to progressive, apply pulldown flags to just those frames, and re-encode without affecting the interlaced video (I still have the original AVI so I'd use that, not go from MPEG2 to MPEG2). That way players that have problems detecting cadence won't try to deinterlace the telecined portion. I haven't found any freeware tools that let you apply flags to specific parts of the file, only to the whole file or to each frame.

[manono]

Hi-

How can I tell for sure that my hardware is correctly applying 3:2 pulldown or if it's just deinterlacing it?

I think you mean to say, "is correctly applying IVTC or if it's just deinterlacing it?

Step through it during a motion section. If it's being deinterlaced, depending on exactly how it's being deinterlaced, you'll find either that every 5th frame is a duplicate frame, or that 2 of every 5 frames is blended. I'd be curious what you find. I've read of new ATI and NVidea cards being able to do on-the-fly IVTCs, but don't have one that can.

Also, just out of curiosity I was wondering if there's some way to apply 3:2 pulldown to restore the frames of the film portion to progressive, apply pulldown flags to just those frames, and re-encode without affecting the interlaced video

Again, I think you mean to say IVTC instead of apply 3:2 pulldown.

What's the ultimate destination? If DVD, the only way I know is to encode each part separately and join during authoring, after applying pulldown to the progressive 23.976fps parts. I've done it a few times myself. There are some other formats that allow for VFR, such as Matroska (MKV).

[Mizkreant]

Step through it during a motion section. If it's being deinterlaced, depending on exactly how it's being deinterlaced, you'll find either that every 5th frame is a duplicate frame, or that 2 of every 5 frames is blended. I'd be curious what you find. I've read of new ATI and NVidea cards being able to do on-the-fly IVTCs, but don't have one that can.

It appears to be doing both. Sometimes every fifth frame is repeated, other times I can see that combed portions of the image are being blended. Even weirder is that a rare number of frames still have combing artifacts (are not being deinterlaced at all). Is that possible? Maybe the AVIVO pulldown detection keeps falling back to video mode? At playback speed, it looks fine. I think my eyes can detect a slight strobing effect from the repeated frames/blending, but that could also be due to the many quick camera movements in this clip. I'm using MPC to step forward/back, the decoder is Dscaler5 set to NV12 colorspace. I can only get hardware acceleration to work in VMR7 windowed mode. VMR9 renderless doesn't deinterlace at all, and VMR9 windowed mode is using bobbing for some reason.

What's the ultimate destination? If DVD, the only way I know is to encode each part separately and join during authoring, after applying pulldown to the progressive 23.976fps parts. I've done it a few times myself. There are some other formats that allow for VFR, such as Matroska (MKV).

The main use is going to be computer playback, but I wanted to remain flexible in case I want to burn it to DVD in the future so I didn't deinterlace during encoding (I'll let the player handle it). So the MPEG2 standard doesn't allow ranges of frames to be marked with pulldown flags? How do professionally produced DVDs do it? If, let's say there's a documentary film transfered to DVD that contains both film clips and video, it's either all interlaced with hard telecining, or progressive frames marked with pulldown flags, but can't have both?

[manono]

Is that possible?

I don't know, it's your card, not mine.

Maybe the AVIVO pulldown detection keeps falling back to video mode?

Very possible. Especially if you're getting quick switches between hard telecine and regular interlaced video.

I think my eyes can detect a slight strobing effect from the repeated frames/blending

Yeah, that strobing effect is common when it's only doing a blend deinterlace. If it's deinterlacing by producing duplicate frames (a bob or motion adaptive deinterlace), you'll get a slight jerky or stuttery playback, especially noticeable during certain kinds of movement.

So the MPEG2 standard doesn't allow ranges of frames to be marked with pulldown flags?

Of course it does. Anime, especially, is often a mix of 23.976fps progressive with pulldown and hard telecined film and sometimes 29.97fps either interlaced or progressive. I don't know how they create it. And documentaries also sometimes have it. Even regular DVDs of movies will sometimes drop to video for no good reason, especially at chapter breaks.

If, let's say there's a documentary film transfered to DVD that contains both film clips and video, it's either all interlaced with hard telecining, or progressive frames marked with pulldown flags, but can't have both?

Yes, you can have both. But you don't usually have both. Docus using a mix of film and video usually hard telecine the film, so the whole thing is encoded as interlaced 29.97fps. Like I said, anime is the genre that most often mixes soft telecined film with hard telecined film and/or video.

There's nothing really wrong with reencoding the whole thing as interlaced 29.97fps. After all, you said that the retail DVD is encoded that way. You lose quite a bit of compression efficiency when compared to encoding the film parts as 23.976fps with pulldown, though. And it could make a significant difference in the overall quality if being reencoded for a DVD5.

[Mizkreant]

I guess I'll leave the whole clip as interlaced NTSC then. It's a small 6 min. clip which comes out at 276 MB, so compression efficiency isn't much of an issue. I'm starting to suspect that select flagging of frame sequences with pulldown tags might be a feature reserved for high end commercial encoders. I haven't come across any inexpensive or freeware tools yet that seem to do it.

[45tripp]

A guy named Bloom hacked dgpulldown to do it

http://forum.doom9.org/showthread.php?t=110256

I've not tried it. never had reason to.

gl

[Mizkreant]

I found another tool David Bloom wrote to generate custom pulldown flags for TMPGEnc. Too bad I only have the free version and the MPEG2 support expired. The documentation is also pretty complex and I'm having a hard time understanding it. For anyone interested, you can find it at: http://davidbloom.home.mchsi.com/readme/readme.html.