3:2 pulldown question.

[BabaLouie]

Hey, I have a question.

Whenever I download 29,97fps NTSC VCD/SVCD files, it seems there are 2 kinds of conversions for a 23,9 to 29,9fps conversion.

The first one I encountered had a pattern of 4 progressive frames followed by an extra added frame.

The second one, which was the exact same music video, but in SVCD, had a pattern of 3 progressive frames followed by 2 interlaced frames.

Whenever I have a progressive 23,9fps file and I convert it to 29,9fps in TMPGenc, I end up with the first pattern and when I check the 3:2 pulldown option, I end up with the second pattern.

However, when I do the 3:2 pulldown, I always get a pattern of 3 progressive frames followed by 2 interlaced frames that consist of obvious "scanlines" or whatever you call them.

Why is it that my downloaded music videos that have 3:2 pulldown, do NOT have a scanlines in the 2 interlaced frames?
Instead, they look more like blended frames.
How do I make my own 3:2 pulldown conversions without those huge lines in the 2 interlaced frames after every 3 progressive frames?

[pijetro]

The second one, which was the exact same music video, but in SVCD, had a pattern of 3 progressive frames followed by 2 interlaced frames.

This is common for movies that have been telecined..Sort of what you'd see if you captured a VHS tape from blockbuster..Unfortunately, whoever encoded the SVCD didn't do a telecide (removal of telecined frames)..

Whenever I have a progressive 23,9fps file and I convert it to 29,9fps in TMPGenc, I end up with the first pattern and when I check the 3:2 pulldown option, I end up with the second pattern.

I would suggest that if you've got a 23.976 progressive frame rate, don't telecine, or change to a 29.97fps via Tmpgenc..
Simply encode your 23.976fps as a Film framerate, and run the Pulldown.exe utility program..
It simply puts flags into the stream, so your player plays back at 29.97fps, and your authouring app recognizes it as 29.97fps..

I believe Tmpgenc does a hard telecine, which is just wasting space...

[BabaLouie]

Even though I know converting to 30fps is useless with the addition of "play as 3:2 pulldown" flags, I love to experiment with things, so I would just like to know how I could do my own 3:2 pulldown conversions without huge scanlines in the 2 interlaced frames.

[adam]

Basically, you'd do a regular 3:2 pulldown and then deinterlace it...yuck.

Those progressive 29.97fps clips you have were most likely filmed at 29.97fps (pure interlaced, nothing but fields) and deinterlaced by either blending the two filelds or discarding one. Those clips you have with 3 progressive frames for every 2 interlaced fields are actually much higher quality, all other things being equal. Those clips retain the full temporal information of the source, whereas the others have either thrown some out or altered it.

If these cliips you are referring to are mpeg2, then it is likely that they are in fact encoded at 23.976fps and have pulldown flags. You should run forced film on them via dvd2avi, to keep them at 23.976fps, then encode as such.

There is nothing wrong with having those two interlaced fields in the clip. This is how just about all NTSC commercial DVDs are. When played on the pc they literally don't exist (if you encoded at 23.976fps with pulldown flags) and when played on a tv they are not visible. This is the preferred way to encode and playback NTSC footage. When played on the tv ALL the frames are displayed as fields anyway.

[BabaLouie]

Basically, you'd do a regular 3:2 pulldown and then deinterlace it...yuck.

When I do the normal 3:2 pulldown and I play the file on my PC, I get 3 progressive frames and 2 interlaced frames that are infested with scanlines.
So to remove those, I have to use the deinterlace filter, but which setting would you recommend?

The only setting that comes close to the desired result is "Double" but it makes the original progressive frames look a little blurry. The scanlines in the 2 interlaced frames are gone though.

[adam]

I'm sure there are various deinterlace routines you could use to remove the interlacing artifacts. I use decomb for everything and it has options that work fairly automatically. No matter what you do its going to give undesirable results. A telecine to NTSC is done by repeating fields, so naturally when you are done you are going to see some interlacing. It is immaterial because you are going to see nothing but fields once its finally played on the tv, but since your eye can't refresh fast enough, they all look like frames.

BTW: when you say 3:2 pulldown you mean "3:2 pulldown when playback" located under encode mode on the video tab right? You'd almost never want to use the 3:2 pulldown filter on the advanced tab. That is for doing a hard telecine.

If you use the first option you will only see the interlacing when you use something like a video editor or an encoder, since it will process the 3:2 pulldown flag normally. If you just play the file via a software player it will do a bob and weave giving you progressive output, just like a progressive scan dvd player would do. Under normal viewing those interlaced fields will never be visible regardless of what you are playing it on.