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Occasional judder and what to do about it? (1 Viewer)

Worth

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Nick Dobbs
How common were films done as 25 fps ?
I don't think there were any films that were made with the intention of being distributed theatrically that were shot at 25fps. The international standard was always 24. There may be a handful of European television productions that were shot at 25 and then saw some kind of theatrical release, but offhand, I can't think of any.
 

jcroy

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So are the digital intermediate transfers today all done in 24 or 30p?

A more relevant question is whether the ota broadcasters and/or cable/satellite operators are using 24 progressive frames-per-second or 60 interlaced frames-per-second (stored/transmitted as 30 progressive frames-per-second) for their live non-on-demand video/audio data transmissions.

About five years ago or so, my previous cable dvr box had a pause mode where one could play advanced frame by frame with each press of a button. From this it was obvious the video signal on many ota broadcast and basic cable channels I had access to, was likely done as 60 interlaced frames-per-second or 30 progressive frames-per-second. (ie. You could see the telecine/pulldown which looks like a "comb effect" pattern for 60 fps interlaced, or a repeating pattern cadence suggesting 30 progressive frames per second).

This is with all the built-in "enhancements" turned off on the dvr and tv.

Nowadays, I have no idea if broadcasters are still doing things as 60 interlaced frames-per-second. My current dvr does not have a pause mode where one can advanced frame-by-frame with the press of a button.
 

TheFOMO

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it feels like judder/stutter could be solved in software if it was important enough - if you can tone map 2000 nits of brightness into a TV capable of only 700 nits, and things still look natural with an overall HDR effect, I'm sure the $$ millions spent on this could also solve motion artifacts
 

Worth

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Anything broadcast over the air is either 1080/60i or 720/30p (or 1080/50i and 720/25p in Europe). Cable and satellite providers may additionally compress those signals, but they don't change the frame rate. The streaming services, at least the big ones like Netflix, Amazon and Disney, use whatever the original frame rate happens to be.
 

jcroy

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it feels like judder/stutter could be solved in software if it was important enough - if you can tone map 2000 nits of brightness into a TV capable of only 700 nits, and things still look natural with an overall HDR effect, I'm sure the $$ millions spent on this could also solve motion artifacts

This is what I do when I'm playing my dvd rips on my desktop computer, connected to my large screen tv via hdmi.

Using the open source video player VLC, I just set the deinterlacing mode to yadifx2 to always being on.
 

jcroy

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jr
Another option is using a hardware processor or software mode (or plugin) which does an "inverse telecine". (For example, VLC has a built in inverse telecine mode as a deinterlacing option).

Basically it takes a 60i (or 30p) video signal, and puts it back together into a 24 progressive frames-per-second video stream. Unfortunately such a simple inverse telecine is highly dependent on the cadence being the same.

To get around this problem of the cadence changing all the time, a smarter "inverse telecine" mode/plugin will be constantly guessing what the pulldown pattern is. It is not foolproof, but it is better than nothing. (For example, "media player classic" with the madVR renderer has a smarter inverse telecine algorithm which does this).
 

TheFOMO

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Another option is using a hardware processor or software mode (or plugin) which does an "inverse telecine". (For example, VLC has a built in inverse telecine mode as a deinterlacing option).

Basically it takes a 60i (or 30p) video signal, and puts it back together into a 24 progressive frames-per-second video stream. Unfortunately such a simple inverse telecine is highly dependent on the cadence being the same.

To get around this problem of the cadence changing all the time, a smarter "inverse telecine" mode/plugin will be constantly guessing what the pulldown pattern is. It is not foolproof, but it is better than nothing. (For example, "media player classic" with the madVR renderer has a smarter inverse telecine algorithm which does this).
This is exactly what I'm talking about - the science and algorithms are there, but nobody cares to standardize this process across the digital distribution stack from post-production to streaming distribution then to TVs. It was done for HDR10 and appears to be doable for motion.
 

jcroy

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The worst culprit for constantly changing pulldown cadences, were some science fiction tv shows from the 1990s. For example, such as Babylon 5.

Whenever I was watching such scifi show dvds on the computer with "media player classic" + madVR, the inverse telecine was constantly guessing the pulldown cadence. (One can toggle on and display the realtime technical statistics on madVR).

I'm guessing the original postproduction editors of such tv shows, just assumed that they were just going to played on standard ntsc cathode ray tube tv screens. So changing cadences wouldn't matter much as long as the flow could be handled as 60 interlaced frames-per-second.
 

Bartman

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I have follow up questions, highly related to this discussion:
1. Would I see a picture quality difference between my Roku 3 and a Roku Ultra (that is capable of outputting 24fps) when streaming movies from Netflix or Prime? Note: in the past when I've compared Blu-ray to streaming, Blu-ray was better.
2. Does the streaming app built into my LG B8 OLED TV also have 24fps capability? Note: I've never used this app.
3. Does the LG app have 24fps 4K capability?

Does anyone have thoughts on these questions?
 

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