Improve Keyframe Preloading to Enable Smooth Navigation Through Entire Videos

[Bindkedon]

Hello,

I really appreciate the great work on LosslessCut — it’s a fantastic tool for fast, lossless video cutting.

However, I’ve noticed that when navigating via keyframes (e.g., using next/previous keyframe shortcuts), LosslessCut only loads keyframes in a small window around the current playback position. This leads to pauses or stuttering when quickly jumping through the video because the player needs to load the next keyframes on demand.

Feature request:
It would be highly beneficial if LosslessCut could (optional) preload or index all keyframes of the video upfront (or at least a larger portion ahead), so that navigation between keyframes is smooth and instant throughout the entire video, even with very long or high-resolution files.

This improvement would greatly enhance the user experience when working with long videos and would reduce frustrating delays during precise cutting or reviewing.

Thank you for considering this feature! I’m happy to provide more details or testing if helpful.

Best regards

[mifi]

I have now implemented this, you can try it in the next nightly build. see also #563

[Lifecarrier]

Could this be tied to a hotkey? I find myself using this feature often and it's a bit of drag having to activate it from the menu each time.

Also, probably a whole different request in itself...is there any way we could choose to preload the entire file (all frames) so seeking would be extremely smooth? Sort of like editors for other purposes do.

I find myself having to create proxy files with shorter GOPs just so seeking is more fluid. It's basically for the same reason this feature was requested.

[mifi]

I've added it as a hotkey now.

Also, probably a whole different request in itself...is there any way we could choose to preload the entire file (all frames) so seeking would be extremely smooth? Sort of like editors for other purposes do.

not sure how that would work. I guess you could use the File -> Convert to supported format, and then choose one of the slow options (that re-encodes the video). that will probably give faster seeking. Other than that I don't know how it can be done.