> Re-encoding just until the nearest keyframe I'm sure is also possible Yer, I've done that, and it's a pain to do "manually" (ie, without having a script ready to do it for you). I've also manually sliced the bitstream to re-insert the keyframe, which if applied to my clip5.mp4 example, could potentially reduce the 50* negative ts frames to maybe 2 or 3. It would be easier if there were tools that could "unpack" and "repack" the frames within the bitstream, and allow you to modify "pointers"/etc in the process - but I don't know of any such thing.