9
billgates
23d

~!dev

If you watch a 30fps video at 2x, is it the same as watching it at 60fps?

I usually watch anime (all videos) at 2x on my phone but when I watch it at regular speed it feels stuttery now but not sure if 2x is the same or it just uses frameskipping. Not sure how that works wither but wouldn't that cause more stutter?

Comments
  • 2
    I'd think so... Interesting question
  • 6
    Depends on how the player handles that. It might be documented, it might not...
  • 2
    It's twice as fast
  • 3
    Technically, yes!
  • 1
    Tech aside;
    Anime tend to reuse frames to avoid redrawing too much. So a video can be 30 fps but with only 2 actual frames for a talking scene;
    - Mouth open
    - Mouth closed
    Repeat each for a few frames and repeat the sequence.

    Watch a real video at 1x and it has less stuttering that anime.
  • 4
    Depends on the implementation of the video player. It could just skip every second frame and still be 30fps or decrease a update timer making it 60fps. In any case it wont look good tho.
  • 0
    @24th-Dragon for the latter I think I get what you mean. Your not seeing more details about what happened in 1s, but rather what happens in 2s gets compressed to 1s.

    Originally was reading some threads about how watching 60fps feels like everything is faster but only thing I seem to notice is the motions are smoother.
  • 2
    You 30frames video is still 60 frames per second. Because that's what your display is capable of (unless you have one of the newer phones with 90hz refreshes but I base my following explanation on the most common 60hz displays) . The player just requests to draw a frame every second refresh of your display.

    By speeding it up 2x your player is now requesting to draw a frame every refresh of your display instead of every second.
  • 1
    Say you want to speed it up 4 times. Your player would request to draw a frame twice every refresh. This Wil not make your output 12frsmes per second you will just see one frame, skip the next, see one, skip the next.
  • 3
    Largely depends on the player and the source video, tho I'm pretty sure all the anime is PAL 24fps or NTSC 29.97fps Interlaced. Videos for online consumption - VOD/streaming go only up to 30fps in most cases and 60 in special/fancy cases (which usually are closely related with gaming or some sort of demonstration).

    Speeding up video to 2x won't change the source of, say 24fps and you'll just dropframes. Tho, how does the player handle the frames if you play back a 24fps video at, say 60fps is where it gets interesting - aproaches and solutions are many and some very complex.
  • 3
    For 2x speed you got 2 options: 30fps rendering that skips every second frame from source, or render in 60fps which means render every frame but for half the time.
    Skipping frames will obviusly get you a worst experience, right? Wrong! Well at least not every time.
    Because anime (or any other animation) most of the time is drawn in 2s (12 frame + 12 duplicate in 24frame) or even higher they achieve 30fps by repeating some frames.
    So a lot of times skipping frames or rendering them for less time creates the same output.
    But even with that if you can you should choose to set the refresh rate higher instead of frame skipping because anime usually change how many frames are drawn in a second. And you should definetly use 60fps if you watch the Fate series because they most of the time animate on 1s and its silky smooth. (Ufotable and its Unlimited Budget Works)
  • 2
    @soulevans07
    "Unlimited Budget Works"
    Hah, a good one.
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