24fps playback of DVD folders on AppleTV 4K

Hello everyone,

I’ve just recently started using Infuse Pro and have been very impressed so far! I’m slowly transferring all of my DVDs and Blu-ray discs to my NAS…

However, I’m wondering if I’m missing something when I play DVD folders (full DVD discs that I’ve transferred to my NAS). I’d like them to play back at 24fps with the 3:2 pulldown removed. This is similar to how my Oppo blu-ray player plays back DVDs; it removes the 3:2 pulldown and plays the movies back at a normal 24/23.976 fps, and my OLED tv tells me that it’s playing at that frame rate. Currently, when I play the DVD files through Infuse Pro 5, the TV tells me that I’m playing back at 60 fps (with pulldown intact, I’m assuming). Please note that I have set my Apple TV 4K to “Match Framerate,” so for instance, my Blu-ray folders/movies do play back at their intended 24 fps on Apple TV 4K through Infuse. But of course, Blu-rays don’t use 3:2 pulldown. Is there anything I’m doing wrong with my setup, or am I requesting a feature that Infuse Pro doesn’t offer yet?

Thanks again for your assistance. I’m very impressed with the product so far!

-Brian

I didn’t see your post before I asked something very similar yesterday about whether HD-DVD’s film-sources would be played in 24p? Or played as 1080p60 with 3-2 frame repetition. The latter would be unacceptable to me. (24p HD-DVD’s are encoded differently than 24p Blu-rays).

I assumed DVD film-sources would be correctly played as 480p24 (or scaled) with 3-2 pulldown removed. I should know better than to assume. No one has responded to either of us so I’m fearing the worse. Is there no setting in Infuse to force 24p for DVD files (and HD-DVD files)?

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Welcome to the forum!

Some DVDs include what is called ‘Hard Telecine’, which means the actual video on the disc is 30fps. This is legacy feature which allowed DVDs to be played on a wider variety of devices, as 60fps is/was a much more common format. There is a technique for reversing this called ‘Inverse Telecine’ (IVTC), and this is something we may look at adding down the road, but it’s not supported right now.

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First thanks for responding. It’s rare to find such supportive developers. I’ve designed algorithms and hardware for Broadcast HD Upconverters, so I’m interested in this issue for my actual needs and I guess curiosity reasons too.

So with respect to playing DVD film content … if you don’t do inverse-telecine to get 24p what is output from an Apple TV using your app? Is it 480i60 with 3-2 pulldown? That would be preferable since that can be optimally converted to 24p with a separate video processor (or TV’s). Or does the Apple TV itself do inverse-telecine and create 480p60 with a 3-2 frame sequence (scaled to 1080p or whatever)? That would not be so good, because only a few processors are designed to identify a 3-2 60p cadence and properly convert back to the original 24p. Or does it output 480p60 (scaled to whatever) with some non-film-mode deinterlacing algorithm? That would be very unfortunate for quality. Sorry I obviously know nothing about the Apple TV or its internal architecture.

I suspect this also means you don’t output 24p for HD-DVD film-source files either? That should be much easier to implement than 24p for DVDs, because you can rely on the repeat_field flags for HD-DVD, rather than 3-2 detection, since they were encoded from 24p transfers (generally the same ones used for Blu-ray). There shouldn’t be faulty flags in those files, whereas DVD’s were notorious for faulty flags, mostly because they were encoded from 480i sources with early MPEG2 encoders. The flag-based 480p inverse-telecine DVD players disappeared very quickly for that reason, and were replaced with 3-2 field detecting inverse-telecine chips. But as I said, I don’t know anything about the Apple TV’s architecture, so I don’t know what you have to work with, so I should probably shut up.

I don’t know how much interest there still is in ripping HD-DVDs, but I know I have about 200 of them. If I can’t get the rips to play at 24p I’ll have to stick with using a standalone HD-DVD player until it dies.

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When playing these in Infuse, they would be sent as 60fps (or whatever fps the video is encoded at) with no extra processing applied. There is an optional deinterlacing feature in Infuse, and we are working on some more advanced deinterlacing options which will be available on newer devices like the Apple TV 4K in Infuse 6.x.

Unfortunately, Apple doesn’t allow apps to adjust the output resolution so this will match what you have set in the main Settings > Video and Audio menu. The Apple TV doesn’t support interlaced output, so everything will be sent as progressive.

Also, I posted a reply in your other thread regarding HD-DVDs. :slight_smile:

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Yes thanks. Sorry about mixing 2 related topics. I’ll just discuss the DVD issue here.

DVD’s encode 24p film-sources as MPEG2 interlaced-sequences of (usually) interlaced fields, i.e. 480i 60(59.94) fields per second. So as I understand it, your app passes the 480i film-source data to the Apple TV’s processing unaltered, but an Apple TV does not output 480i. So it can basically do at least one of three things.

  1. Use inverse-telecine deinterlacing (flag or field detected) to create 480p24 and then output that as 480p24 or scaled to 1080p24 or other 24p format.

  2. Use inverse-telecine deinterlacing (flag or field detected) to internally create 480p24 and use 3-2 frame repetition and scaling to produce 480p60, 1080p60, or other 60p format.

  3. Use non-film-mode deinterlacing to convert 480i 60 fields-per-second to 480p60, and optionally scale to 1080p60, or other 60p format.

#1 is the optimal quality solution for film-sources. #2 is not good because it creates judder. #3 is awful (loss of resolution and deinterlacing artifacts) for film sources.

At this moment we don’t know which of those 3 things the Apple TV does? Or if it can optionally do more than one. Do I have it correct?

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Right now Infuse will do #3.

The Apple TV itself doesn’t include any inverse telecine or deinterlacing features. However, since Infuse uses its own player, deinterlacing is currently available.

It may make some sense to look at adding IVTC as this is related to some of the reworked deinterlacing features we have in progress. Though it’s too early to say if there will be any technical limitations here. Assuming everything works as expected, this would allow Infuse to provide 1080p24 (#1 from the list above).

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I had no idea the Apple TV itself was so limited to not include any deinterlacing. I guess they didn’t have much need to stream interlaced video. I had no interest in the ATV before I decided to create a server for my home theater and needed client hardware. Glad to hear you might consider inverse-telecine. Without it this really isn’t a viable solution (for me) for DVDs, but I don’t know how many people are still ripping DVDs.

As I mentioned, and I’m sure you already knew, flag detection was problematic for 480p/upscaling DVD players. But 3-2 field detection for films is rather simple to implement, if you don’t get hung up trying to detect endless variations of additional odd cadences. That became the (marketing?) rage at one time and solving that 5% problem (probably being generous) just led to sub-par performance for the much larger majority of movie DVDs. Stick to 3-2 detection, keep it simple, and get optimum results for most movies. (And I’d be really surprised if just reading the flags wasn’t completely adequate for film-source HD-DVDs for the reason I mentioned above).

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Thanks so much for your attention to this thread, James and Macy! I agree with Macy that inverse-telecine for 24fps-film-sourced NTSC DVDs would be a great feature for Infuse to offer, and it seems (from my perspective) to be far easier to implement than any other 60i to 30p/60p deinterlacing technology.

Like Macy, I just recently started using Infuse Pro as a media center for my large collection of DVDs and Blu-ray Discs (I had tried Plex in the past, but was unimpressed). My primary reason for switching to (and so far, sticking with) Infuse is the ability to read full DVD ISO/VOB file folders. This is for three reasons: 1) transcoding to another format (even if it reverses the telecine) takes too much additional time, 2) I want to preserve the highest quality possible from the source DVD, and 3) I also want to preserve the menu structure for potential playback (such as is possible with MrMC). However when I noticed that my film-based DVDs were playing back at 60p through Infuse, I was certainly a bit disappointed. However I recognized that all of these Apple TV-based media players are a works-in-progress, so I’m continuing to backup my DVD/Blu-ray collection in the hopes that an ideal solution will someday appear!

And I wonder how many folks even realize that true 24fps playback from film-based NTSC DVDs is possible…? Perhaps this could be another marketing feature for Infuse. It doesn’t appear that either Plex or MrMC is capable of 3:2 pulldown removal. In any case, I hope this is something that your dedicated team can implement in the near future for “purists” like myself and Macy. :slight_smile:

Ha, ha Purist? I suppose so, since I still have 2 Faroudja’s in my obsolete equipment archive, a VP250 line doubler and a DVP3000 1080p Upconverter that I bought for my CRT projectors. Those were the days when a Sony G90 CRT projector weighed 240 pounds. The historical relevance? - Faroudja invented and patented the first inverse-telecine based line-doubler (deinterlacer) in 1989, and the VP250 was his 2nd generation of that technology. The DVP3000 was the first Upconverter with motion-adaptive deinterlacing (for non-film sources) 1080p output.

Anyway, deinterlacing quality, especially for film-sourced DVDs, was the distinguishing criteria for DVD players and video processors until HDTV was introduced. If we are still watching DVDs, it is still critically important. Although inverse-telecine deinterlacing is now routine in video processors and TVs, non-film-mode video deinterlacing is still far from ideal for 1080i broadcast sources.

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I purchased an Apple TV 4K yesterday so I have been able to do some actual experiments, but primarily on HD-DVD sources, and only a few DVD sources.

What I found is this:

To get 24p output from my DVD sources (so far) I must set the Format to 4K SDR 24Hz or 1080p SDR 24Hz (use SDR since HDR didn’t exist for DVDs), AND SET Match Frame Rate OFF. It seems counter-intuitive to set Match Frame Rate OFF, but it’s because of the way 24p film sources are MPEG2 encoded on DVDs. In many (most?) cases they are encoded similar to the method used for HD-DVDs, and those settings would then produce judder-free 24p output. I discussed that here:

However, unlike HD-DVDs, the encoding rules for DVDs allowed several additional encoding methods (I’ll skip the technical details). I haven’t been able to test how the ATV4K will handle those other methods yet. And the flags on DVD’s were notorious for being wrong too often, which would break judder-free 24p output. I’d guess the ATV4K is likely a flag-reader only, and if so should have problems with many DVDs. To get optimum 24p from DVDs normally requires cadence-detecting algorithms, or a combination of cadence-detecting and flag-reading.

I’ve attached a picture captured from a DVD film-source (3-2) moving zone plate test pattern that shows the 23.98p timing and frame rate. The moving zone plate was output without any 3-2 pulldown judder.

Deleted comment (somehow duplicated above comment)

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