> If you have a long video with only a single key frame at the beginning then
...you can't support the scrub bar efficiently either, so no one encodes video that way.
Typically to go to a frame you find the last IDR frame before it (and in reasonable encodings those are frequent enough) and decode forward until you get to the frame of interest. Doing that every time the user presses the single frame back button really doesn't seem that bad, and neither does holding onto some extra reference images for at least like 1080p frames. (8k video and such starts getting more expensive but maybe even then start doing all some references after the first press of the frame back button in this GOP or some such.)
It's of course work to do, and I'm not super motivated to send them that patch, and there's the question of it it would be merged and maintained indefinitely, but what folks are asking for is technically possible.
> I don’t see any reason it couldn’t be supported for a set of formats with reasonable encoding/decoding settings, and provide some error message for other formats if a user attempts to step back, e.g. reverse frame stepping unavailable for current video due to format/encoding/decoding settings.
Yeah, this. That's likely more or less what they already do with the scrub bar.
...you can't support the scrub bar efficiently either, so no one encodes video that way.
Typically to go to a frame you find the last IDR frame before it (and in reasonable encodings those are frequent enough) and decode forward until you get to the frame of interest. Doing that every time the user presses the single frame back button really doesn't seem that bad, and neither does holding onto some extra reference images for at least like 1080p frames. (8k video and such starts getting more expensive but maybe even then start doing all some references after the first press of the frame back button in this GOP or some such.)
It's of course work to do, and I'm not super motivated to send them that patch, and there's the question of it it would be merged and maintained indefinitely, but what folks are asking for is technically possible.
> I don’t see any reason it couldn’t be supported for a set of formats with reasonable encoding/decoding settings, and provide some error message for other formats if a user attempts to step back, e.g. reverse frame stepping unavailable for current video due to format/encoding/decoding settings.
Yeah, this. That's likely more or less what they already do with the scrub bar.