Nostalgic Erotica Prod said: Splitting the file by parts (strip scene, oil scene/round 1/round 2/round 3 for example) seems to be the only way
Doing it based on the rounds makes sense. But just to try, I've re-encoded one of your recent files to half its original bitrate and placed it into your bin so you can preview it. Took it from 10,500Kbps down to 5000 and half the file size, and I can *barely* tell the difference on my 4K monitors. Don't expect you to take it that low, but it looks good even with lots of full-frame motion. You can delete the test file anytime but I just wanted to show you that test.
I routinely work with producers on tweaking their compression settings to suit their particular content. Anyone can hit me anytime and I can have UMD run some proof of concepts for you.
WARNING: boring geek rant aimed at producers ahead ---
I have said this many times in the past, but it bears repeating. Never ever EVER! use the default rendering presets in ANY editor. They are all pure garbage and typically only include one that's nearly raw and one that was clearly designed for dialup. Also, never use constant bitrate. Variable bitrate typically saves 10-20% on file size with virtually no visible difference.
Cut a chunk of your source video that is exactly 60 seconds and has a decent amount of movement in it (makes the math easier and the rendering time short), then make a bunch of test renders. Start with one of your editing programs "high quality" variable bitrate presets. After that, modify that preset with a lower average bitrate and SAVE it as a new preset with a different name. Make another at a lower bitrate, and so on. Personally, I am still shooting 1080 HD (4:2:2 50mbps MXF) and have presets at 1mbps intervals from 10 down to 4. The type of content is what determines your optimal bitrate. Running water needs 10. Talking heads are fine at 4. You can probably 1.5x or 2x those numbers for 4k using h.265 codecs. Do a handful of renders and view them on your monitor and on your phone from various distances. Be honest with yourself. If possible, do a blind test by getting someone else to start the videos randomly so you don't know what bitrate you are watching. As is the case in most blind studies, you'll find that your preconceived notions are basically all wrong.
Also keep in mind that shooting at 60 fps generates a file that is automatically twice the size of 30fps footage. 4k is 4x larger than HD by resolution, but h.265 (HEVC) allegedly compresses twice as good as h.264 (HD) so in most consumer cameras, the source files will be only about twice the size of 1080 HD at an equivalent framerate.
As mentioned above, 4k is pretty pointless for distribution. The vast majority of viewing is done on cell phones and it's physically impossible for most people to see a difference between 4k and 1080 on a 5-6 inch screen. If you think otherwise, you are deluding yourself. Even on a large monitor, there is very little difference between 1080 at 20mbps and at 10mbps. This is not Hollywood. You are not getting an Academy Award Nomination for any of this stuff. We make and sell fetish videos. It's jerk-off material, not cinematic masterpieces. You are (probably) not Fellini or Spielberg
Aside from the storage issues, multi-gigabyte files are still problematic on many of the garbage cable internet systems in the US, which is our primary market. It's an even larger problem on transatlantic connections to EU, JP, AU, etc. Neither the UMD nor Vidown can afford to employ vast global content distribution networks. If we did, videos would cost twice as much. Vidown has some 5-10 GB files in various catalogs and they are always a problem. Usually the solution is to tell the customer to download the file very late at night or early in the morning when their shitty Comcast internet is far less likely to shit the bed mid-download.
In summation, play with your editor's compression settings and find the smallest levels you are comfortable with. It's work, but it has to be done. Both systems rely on producers knowing a little something about their editing process. The alternative is to do it like 100% of all tube sites, which recompress all uploads to something that the system deems appropriate, which you will probably not agree with.