Well probably for a while already, but I just discovered it now. Wanted to post this here, in case someone also didn't know. On my system ffmpegis a lot quicker in encoding than any adobe software.
How do I encode something into HAP with ffmpeg?
like this:
ffmpeg -i "path_to_inputfile\inputfile.mov" -c hap -an -sn "path_to_outputfile\outputfile.mov"
-an is for no audio, -sn for no subtitles. supplement 'hap' by 'hap_alpa' or 'hap_q' in case you want those. As far as my tests showed, there's no possible way to influence the bitrate, or the quality otherwise.