I was insufficiently precise in my description, but having implemented it in one (admittedly simple) codec I can assure you it works. ::grin:: When this kind o

I was insufficiently precise in my description, but having implemented it in one (admittedly simple) codec I can assure you it works. ::grin:: When this kind of rolling keyframe is used the encoder needs to track the reference structure of the video and not make any references into the "dirty zone"-- this includes constraining coding modes so that no entropy context leaks. This can be aided by (or necessitate the use of) 'tiled'/'sliced' entropy coding features that some codecs have for parallelism reasons. There is, of course, a coding performance loss-- especially if the video pans against the update boundary.