ffmpeg lossless for archive.org and reverse order of frames

Archive.org did not accept zip files containing frames for uploading 4K content, but lossless codecs were accepted.

ffmpeg - Best Lossless Video Codec for 8 bpc RGB image sequences? - Super User

seems to indicate that the best seems to be x265,

and commandline

How to get a lossless encoding with ffmpeg - libx265 - Stack Overflow

 

ffmpeg -i input.mp4 -c:v libx265 -x265-params lossless=1 output.mp4 

And for reversing the frame order (backwards video),

ffmpeg - convert image sequence to video with reversed order - Stack Overflow

 

- first bulk rename to - (minus) for the numbers prefix.