lossless is truly lossless

losslesshp is +10% perf for a slight file size increase

lossless is actually faster than x264 and x265 lossless mode while being more efficient

lossless corresponds to a quality level of -12 (q=-13), inaccessible through normal modes ([0...51]) i.e. effectively disable quantization. for x265 this is qp=4, x264 qp=0.

example:

frame=141336 fps= 78 q=-13.0 Lsize=439591079KiB time=01:38:14.88 bitrate=610890.2kbits/s speed=3.26x elapsed=0:30:08.07

losslesshp on the 4k 98min video gives you a 450gb file (about 20x vs the original) for a compression ratio of ~4.9:1