[ZwartePiet]

Most DVDs in Region 1 are either progressive or telecined. Only the handful of DVDs containing TV-shows filmed on video-tape require de-interlacing.

MMAL-advanced does a good job getting rid of the jaggies, but it's not perfect and the 3:2 cadence is still obvious to a trained eye. All the information is there to reconstruct a fully progressive video. Open-source software like VLC have had IVTC for awhile. The processor-load should also be low. It would be a major plus for owners of Region 1 media (particularly TV-shows on DVD) if the Pi could playback their video perfectly.

[noggin]

Most DVDs in Region 1 are either progressive or telecined. Only the handful of DVDs containing TV-shows filmed on video-tape require de-interlacing.

MMAL-advanced does a good job getting rid of the jaggies, but it's not perfect and the 3:2 cadence is still obvious to a trained eye. All the information is there to reconstruct a fully progressive video.

Open-source software like VLC have had IVTC for awhile. The processor-load should also be low. It would be a major plus for owners of Region 1 media (particularly TV-shows on DVD) if the Pi could playback their video perfectly.

I guess what you are asking for is a deinterlaced from 60i to 24p progressive rather than from 60i to 60p progressive, with a change of refresh rate output happening when the 3:2 cadence is detected and removed. That would work for a fixed-cadence source (say a movie DVD that respects 3:2 properly), but would be a nightmare for 60i Live TV sources, shows where 3:2 telecine content has been edited 60i, ignoring 3:2 cadence, or where 24p content is mixed with 60i native - often on screen at the same time. Imagine a 3:2 TV show with a 60i 1:1 crawl graphic over it?

I think there is an argument for 3:2 detection and conversion to 24p - but only if forced manually? There is no guarantee a cadence will be constant or continuous - so you do have to allow for that - and having your TV re-sync as a 60i studio show cut to a 24p 3:2-ed clip during an interview would be painful.

That said, I've never seen VLC change refresh rate (can it?) - so you'd still have to manually switch to 24p to get 3:2 removed if VLC was playing a 60i source that contained 24p with 3:2?

However IVTC doesn't have to mean 3:2 cadence removal. It's often used to describe converting 60i with 3:2 to 60p with 3:2 but with recognition of the 60i frames containing source fields from two different 24p frames, and the reconstruction of a 60p sequence with clean 24p frames, albeit still with a 3:2 cadence. Effectively converting 60i to 60p but avoiding mixed frames.

There are three real ways of deinterlacing 60i content with 3:2 24p within it :

1. deinterlace to 24p - detect the 3:2, remove the repeated field, create a 48i sequence and weave it to 24p. 60i in, 24p out. (This will fall apart if the source contains mixed 60i native and 24p content)
2. deinterlace to 60p - detect the 3:2, remove the repeated field, create a 48i sequence, weave to 24p and then 3:2 frame repeat to 60p. 60i in, 60p out. (This will also cope with mixed 60i native and 24p content - but not when it is on-screen at the same time)
3. deinterlace to 60p - deinterlace using whatever algorithm you like that copes with 1:1, 2:2 and 3:2, and output 60p. This is what broadcast de-interlacers and up-converters usually have to do - 480/60i in, 720/60p or 1080/60i out. Some will detect areas of the picture with 3:2, and follow the processes of 2. (but not over the whole picture). They therefore cope best with content which constantly changes cadence OR content where you have 24p and 60i sources on-screen at the same time - say with a split screen, or a 60i camera pointed at a presenter or actor in front of a projector showing 24p content, or where you have split-screens with 60i on one side of the screen and 24p sourced content on the other.

(And of course it's not a problem in PAL-land where we are 2:2)

[ZwartePiet]

I guess what you are asking for is a deinterlaced from 60i to 24p progressive rather than from 60i to 60p progressive, with a change of refresh rate output happening when the 3:2 cadence is detected and removed. That would work for a fixed-cadence source (say a movie DVD that respects 3:2 properly), but would be a nightmare for 60i Live TV sources, shows where 3:2 telecine content has been edited 60i, ignoring 3:2 cadence, or where 24p content is mixed with 60i native - often on screen at the same time. Imagine a 3:2 TV show with a 60i 1:1 crawl graphic over it?

My TV is 60Hz, so 60i to 60p would suit me fine.

I should have re-phrased my issue with the 3:2 cadence. The problem wasn't judder (which is annoying...), but the noticeable difference between progressive and de-interlaced frames. Removing 3:2 pulldown would be great for those with 24p sets.

I think there is an argument for 3:2 detection and conversion to 24p - but only if forced manually? There is no guarantee a cadence will be constant or continuous - so you do have to allow for that - and having your TV re-sync as a 60i studio show cut to a 24p 3:2-ed clip during an interview would be painful.

Manual-only would be fine for local media. I'm not sure of the intricacies of Kodi, but the library seems to tag my DVD rips automatically. In a perfect world, Kodi would know it's playing a DVD and automatically inverse telecine when appropriate. I don't know if (all) professionally mastered DVDs are encoded with the proper flags or if Kodi would need to do some kind of fancy on-the-fly detection. VLC can do its magic when manually selected, so I assume it's a solved problem.

I'm not concerned with TV for the problems you've noted and also because 1080i is enough resolution to mask the problem, IME. All broadcast 480i channels in this part of the world are compressed into such oblivion it would just be putting lipstick on a pig.

That said, I've never seen VLC change refresh rate (can it?) - so you'd still have to manually switch to 24p to get 3:2 removed if VLC was playing a 60i source that contained 24p with 3:2?

However IVTC doesn't have to mean 3:2 cadence removal. It's often used to describe converting 60i with 3:2 to 60p with 3:2 but with recognition of the 60i frames containing source fields from two different 24p frames, and the reconstruction of a 60p sequence with clean 24p frames, albeit still with a 3:2 cadence. Effectively converting 60i to 60p but avoiding mixed frames.

I've only used VLC with DVD rips on 60Hz displays, successfully IVTC 60i to 60p.

(And of course it's not a problem in PAL-land where we are 2:2)

Yeah, I have Region 2 DVDs of a few TV shows and they work fine. Doesn't 2:2 pulldown cause an increase in audio pitch for you 50Hz guys, though?

[noggin]

Yeah, I have Region 2 DVDs of a few TV shows and they work fine. Doesn't 2:2 pulldown cause an increase in audio pitch for you 50Hz guys, though?

Pitch is usually corrected, but speed isn't. I remember being surprised how much slower US TV shows were when I started hearing them on Blu-ray at 24p instead of broadcast with 4% speed-up as 25p at 50i.

Now I understand your question - I guess that the YADIF 2x (or close equivalent) that is being used on the Pi 2 is not optimised for 3:2 content (and so gets a bit confused by the mixed-frame which has a field from one source frame and the other from a different frame) I guess detecting repeat fields and removing them would require a different approach.

[ZwartePiet]

Just to be clear, the Model 2's advanced de-interlacer really does a good job. I only notice jaggies on slow-moving, high-contrast fine lines, like the brim of a person's hat. The current de-interlacer gets to about 95% of perfection. Adding IVTC would only be for pedantry (i.e. the last 5%) and to be "feature complete."

I don't remember if the Model 1's can do advanced de-interlacing on SD content. If they're stuck with bob, then IVTC might be a lightweight way to get a big image-quality boost for certain content. In any case, if the Pi team is looking for minor ways to add value to the device, IVTC may be worth a look.

[noggin]

Think the Pi 1 does MMAL Advanced on SD 480i and 576i stuff. The Pi 2 does MMAL Advanced at 1080i with some overclocking (but I don't THINK the Pi 1 can do this).

I guess 3:2 detection and removal would add to the quality of the deinterlacing for 60Hz territories (it's not an issue on 50Hz stuff), but it's also quite a deviation from Bob and YADIF 2x, and may require some quite clever buffering, as it effectively requires a 60i to 24p/48p/48i to 60p route to exist, which is quite different to a straight 60i to 60p route, AND you have to detect the 3:2 cadence (and ideally cope when it is disturbed - which happens on US TV at ad-breaks).