Hello,
I managed to shed some serious file size by removing quality that the average fapper probably won't notice nor care about:
- Scale everything to max height = 1080px, max width = 1920px
- Downmix audio to Stereo
- Reencode to H265 + Opus
Size improvements range from 3x to 20x, most notably with the more recent stuff and also 2019, which for some bizarre reason uses
WMV3. In total, I managed to lose 16.2GB (18.2GB -> 2GB).
Unfortunately, I was already halfway done when I noticed that these are all 60fps. However, a quick test told me that reducing to 30fps wouldn't yield a lot (~20% less compared to the compressed 60fps version), so I stuck with 60.
Edit: Oh, and I accidentally used Vorbis for some of them instead of Opus. Whoopsie! The big kicker is H265 anyways, so it doesn't matter much, if at all.