6 ms·

I never understand why playing at wrong FPS for these old-time footage is a thing. It was so obviously wrong. (By that I meant in "professional" settings, like

I never understand why playing at wrong FPS for these old-time footage is a thing. It was so obviously wrong. (By that I meant in "professional" settings, like a commercial release. You see people stretching 4:3 videos to 16:9 all the time on YouTube, Tiktok etc. but at least Warner Bros. isn't going to do that. However the FPS incorrectness used to be prevalent even in the industry.)

callalex 3y ago
Well, tv stations these days speed up the playback of older shows by a few percent so they can fit more commercials in than the original creator provided time for. I’m so glad I haven’t payed for cable in a very long time.
- toast0 3y ago
  If you're lucky they speed up the playback. If you're not, they cut to commercial on a schedule, damn the content. Doesn't matter if you miss the punchline of the joke that was being setup this whole time. Of course, it's worse with online tv with ad breaks. The online ads cut in 2-5 seconds before or after the program break, so it interrupts the content, and if you skip back to try it again, they play another ad, also inserted incorrectly. To make it even worse, the ads are usually at a different framerate and resolution from the content, so you get a new resync and a new hdcp handshake, so there goes another few seconds of content; unless you set your player to fixed resolution and framerate which isn't ideal. I'm in prime circumstances to be a couch potato in front of the tv, but it's so damn frustrating, it's not worth it. You can't even channel surf, because tuning a new channel takes too long, so you've got to plan your changes.
toast0 3y ago
> I never understand why playing at wrong FPS for these old-time footage is a thing. It was so obviously wrong. Old-time footage isn't always at 24 fps, but once the film industry standardized hard on 24 fps, not standard film becomes very hard to use correctly, even in a projection environment --- projectors were engineered around 24 fps all the time, and likely can't be adjusted. Tv of course was fixed at 60 fields per second (or close enough) or 50 in Europe. Even today, a US market tv is going to do terrible things with a 50 fps signal (although I gather EU market tvs work at 50 and 60 and probably 24). If your old-time film was shot at 22.3 fps, you don't have good options to show it, except on a computer with a VRR display, and even then, I don't know if the whole chain will actually be fine with it. Options are: pretend it is 24 fps and it plays a bit fast and you can use your 24fps pipeline; show some frames twice and have nasty judder; interpolate 24 fps from the data you have which is kind of terrible and only recently a real option.
- thrdbndndn 3y ago
  Off topic, but what's the difference between the term jitter and judder? I've tried to google it multiple times, but every time, I can only find various forum posts which are all over the place (if not straight up contradict to each other).
  - tetris11 3y ago
    From context I would guess that judder is a global effect (e.g. when the film pauses and then suddenly jerks forward playing), and that jitter is more local (e.g. to do with the movements of the actual characters on screen moving with sudden velocity)
  - keithwinstein 3y ago
    My understanding is that jitter refers to essentially stochastic variation of an ideally isochronous/periodic process or signal. You might say "the event is supposed to occur exactly every 1 second; in practice we observed jitter of +/- 50 milliseconds," referring to the RMS (1-standard-deviation estimate) of a sample of inter-event durations. Wikipedia has a nice article: https://en.wikipedia.org/wiki/Jitter https://en.wikipedia.org/wiki/Jitter In the context of video, I think the most common use of "judder" is about the deterministic and periodic variation in timing that occurs when content of one frame rate is shown on a different-rate display. The most common situation is a "3:2 pulldown," where 24 frame-per-second film content is adapted to a 60 field-per-second or frame-per-second video signal. This is done by repeating one film frame for 3 video fields/frames (so 3/60 seconds), and then the next film frame for 2 video fields/frames, then the next one for 3, then 2, then 3, then 2, etc. (2/5 = 24/60 so it works out on average.) That repeating variation in frame duration or number of repetitions is seen as "judder." With a cinema projector or recent TV, you don't have this; the frames are shown 1/24 s apart and with an equal number of flashes each. But on an older 60 Hz TV, you'll have judder. (I've also seen "judder" occasionally used to refer to the stuttery motion that comes from showing 24 fps content on a sample-and-hold display, like an OLED [without black-frame insertion] or a "good" LCD that just shows each frame with constant brightness for the entire 1/24 s and then almost-instantly switches to the next frame. But I don't think this is the correct usage.)
ok_dad 3y ago
How do you suggest taking 24 FPS and turning it to 29.976 NTSC? A lot of times, they would just convert it 1:1, so the 24 frames would go by in a 24/~30th of a second, so it looked faster. Further, a lot of old, old film was actually meant to be played at slower FPSes than 24, I think 8mm was like 18 FPS. Today, we do key-framing and other tricks to make transfers from different FPSes easy and imperceptible (plus with digital stuff we can playback at any FPS), but back in the 80's and 90's the tech was a lot less advanced to turn a film image into an analog or digital format, and in previous decades you didn't even have analog or digital, you just had to use 1:1 frame transfers to get onto a larger or smaller film format.
- charcircuit 3y ago
  As professionals they should be shooting at 29.976 fps if that is the fps the end product is supposed to be. Messing up and using the wrong framerate when recording is for amateurs.
  - rjmunro 3y ago
    The end product is supposed to be 24fps for a cinema. But then a TV company wants to show the already-existing film. It needs to be solved. In PAL countries, 24fps movies are often played a bit fast at 25fps on TV so that each frame fits nicely in the 50hz signal. It's not a "Squeeze more adverts in" thing, it's the best way to show the film, otherwise you'd have to introduce an extra frame every second, which would look jarring.
- sgtnoodle 3y ago
  24FPS is typically converted to 60Hz using 3:2 pulldown. Show one frame for 3 fields, then the next frame for 2 fields, then 3, then 2, etc.
- thrdbndndn 3y ago
  > How do you suggest taking 24 FPS and turning it to 29.976 NTSC? 3:2 pulldown, which has been done for decades. You can also just duplicate frames (un-evenly). It will introduce jitter but most of people aren't very sensitive to that, and it's better than playing at wrong speed.

callalex 3y ago

Well, tv stations these days speed up the playback of older shows by a few percent so they can fit more commercials in than the original creator provided time for. I’m so glad I haven’t payed for cable in a very long time.

toast0 3y ago
If you're lucky they speed up the playback. If you're not, they cut to commercial on a schedule, damn the content. Doesn't matter if you miss the punchline of the joke that was being setup this whole time. Of course, it's worse with online tv with ad breaks. The online ads cut in 2-5 seconds before or after the program break, so it interrupts the content, and if you skip back to try it again, they play another ad, also inserted incorrectly. To make it even worse, the ads are usually at a different framerate and resolution from the content, so you get a new resync and a new hdcp handshake, so there goes another few seconds of content; unless you set your player to fixed resolution and framerate which isn't ideal. I'm in prime circumstances to be a couch potato in front of the tv, but it's so damn frustrating, it's not worth it. You can't even channel surf, because tuning a new channel takes too long, so you've got to plan your changes.

toast0 3y ago

> I never understand why playing at wrong FPS for these old-time footage is a thing. It was so obviously wrong. Old-time footage isn't always at 24 fps, but once the film industry standardized hard on 24 fps, not standard film becomes very hard to use correctly, even in a projection environment --- projectors were engineered around 24 fps all the time, and likely can't be adjusted. Tv of course was fixed at 60 fields per second (or close enough) or 50 in Europe. Even today, a US market tv is going to do terrible things with a 50 fps signal (although I gather EU market tvs work at 50 and 60 and probably 24). If your old-time film was shot at 22.3 fps, you don't have good options to show it, except on a computer with a VRR display, and even then, I don't know if the whole chain will actually be fine with it. Options are: pretend it is 24 fps and it plays a bit fast and you can use your 24fps pipeline; show some frames twice and have nasty judder; interpolate 24 fps from the data you have which is kind of terrible and only recently a real option.

thrdbndndn 3y ago
Off topic, but what's the difference between the term jitter and judder? I've tried to google it multiple times, but every time, I can only find various forum posts which are all over the place (if not straight up contradict to each other).
- tetris11 3y ago
  From context I would guess that judder is a global effect (e.g. when the film pauses and then suddenly jerks forward playing), and that jitter is more local (e.g. to do with the movements of the actual characters on screen moving with sudden velocity)
- keithwinstein 3y ago
  My understanding is that jitter refers to essentially stochastic variation of an ideally isochronous/periodic process or signal. You might say "the event is supposed to occur exactly every 1 second; in practice we observed jitter of +/- 50 milliseconds," referring to the RMS (1-standard-deviation estimate) of a sample of inter-event durations. Wikipedia has a nice article: https://en.wikipedia.org/wiki/Jitter https://en.wikipedia.org/wiki/Jitter In the context of video, I think the most common use of "judder" is about the deterministic and periodic variation in timing that occurs when content of one frame rate is shown on a different-rate display. The most common situation is a "3:2 pulldown," where 24 frame-per-second film content is adapted to a 60 field-per-second or frame-per-second video signal. This is done by repeating one film frame for 3 video fields/frames (so 3/60 seconds), and then the next film frame for 2 video fields/frames, then the next one for 3, then 2, then 3, then 2, etc. (2/5 = 24/60 so it works out on average.) That repeating variation in frame duration or number of repetitions is seen as "judder." With a cinema projector or recent TV, you don't have this; the frames are shown 1/24 s apart and with an equal number of flashes each. But on an older 60 Hz TV, you'll have judder. (I've also seen "judder" occasionally used to refer to the stuttery motion that comes from showing 24 fps content on a sample-and-hold display, like an OLED [without black-frame insertion] or a "good" LCD that just shows each frame with constant brightness for the entire 1/24 s and then almost-instantly switches to the next frame. But I don't think this is the correct usage.)

ok_dad 3y ago

How do you suggest taking 24 FPS and turning it to 29.976 NTSC? A lot of times, they would just convert it 1:1, so the 24 frames would go by in a 24/~30th of a second, so it looked faster. Further, a lot of old, old film was actually meant to be played at slower FPSes than 24, I think 8mm was like 18 FPS. Today, we do key-framing and other tricks to make transfers from different FPSes easy and imperceptible (plus with digital stuff we can playback at any FPS), but back in the 80's and 90's the tech was a lot less advanced to turn a film image into an analog or digital format, and in previous decades you didn't even have analog or digital, you just had to use 1:1 frame transfers to get onto a larger or smaller film format.

charcircuit 3y ago
As professionals they should be shooting at 29.976 fps if that is the fps the end product is supposed to be. Messing up and using the wrong framerate when recording is for amateurs.
- rjmunro 3y ago
  The end product is supposed to be 24fps for a cinema. But then a TV company wants to show the already-existing film. It needs to be solved. In PAL countries, 24fps movies are often played a bit fast at 25fps on TV so that each frame fits nicely in the 50hz signal. It's not a "Squeeze more adverts in" thing, it's the best way to show the film, otherwise you'd have to introduce an extra frame every second, which would look jarring.
sgtnoodle 3y ago
24FPS is typically converted to 60Hz using 3:2 pulldown. Show one frame for 3 fields, then the next frame for 2 fields, then 3, then 2, etc.
thrdbndndn 3y ago
> How do you suggest taking 24 FPS and turning it to 29.976 NTSC? 3:2 pulldown, which has been done for decades. You can also just duplicate frames (un-evenly). It will introduce jitter but most of people aren't very sensitive to that, and it's better than playing at wrong speed.