Using handbrake, I can get virtual ntsc quality movie files that are under 300 megs for 1.5-2 hours. Here, a half hour of 480 takes 300 megs.
First, I realized that 420 and 480 lines look inconsequentially different. Going below 420,I could see degradation. Then I realized 22.5 frames per second was plenty for %99.999 of movie scenes. Then I cut out bottom %15 of screen, realized nothing ever happens at bottom of screen. %15 was plenty safe for subtitles. Then, naturally, h.264, was 2x better than mpeg 2,back in 2014. I shared a planet of apes rip to a broadcast editor who was impressed with the quality size ratio.
Today h265 is 2x 264. I have played with bpg who uses the key frame from h.265. A still image was twice as efficient as webp and 4x better than jpg.
So a customized frame rate, 420 lines, cropping, and h. 265 would turn my 1tb hard drive into a 6tb. With less wear and tear.