I basically added max_extra_cb_iterations=0 min_strips=3 this speedups encoder but quality is lower (not sure how much, was too inpatient to wait for 1 min clip encode at 352*144 25 fps! with those parameters ffmpeg encodes at nearly 3 fps, yay! In theory one can try to set up renderfarm + number parallel ffmpeg encoders, because encoder is single threaded - but I haven't tested this) also added two old (1996/8) h263 codecs - it theory they should be good for low-cpu decoding (on emulated computers for example), but apparently h263 without 'p' only good at few pre-defined resolutions? there is also speedhq.qt - for ffmpeg 4.4 (sadly ffmpeg can't encode video with alpha, as this mpeg2-like format supports...) sorry for not making progress on more important issues - I fiddled around with overlayframe.h - but I can't see my addons working? Either bug in code or I translated those blend modes wrongly.. there also two ffmpeg-4.4 patches recently added to git - they apply with patch -p1 yet not with git apply patch (misformatted patch).. Adds avc intra 300/480 if compiled against last x264 (15 june 2021)