Then it adjusts how much compression it applies scene-by-scene to hit that quality mark.

Constant quality asks you how close to the original, uncompressed file you want the compressed version to look.

To make a very, very long story short, you have two options when compressing a video with H.264 or HEVC. (Big thanks to transcoding wizard Don Melton for his expertise on this next part.) HandBrake 1.2.0 and later enables Apple's VideoToolbox technology to dramatically speed up H.264 (and, for users of post-2017 Macs, HEVC) encoding … but there's a slight catch. Again, the trade-off here boils down fairly simply: a longer wait for smaller files, or a much shorter wait for somewhat larger ones. Once you've picked an algorithm, you need to decide how you're going to apply it to your video. They're generally considered comparable in quality to H.264 and HEVC, respectively. (Note that on some newer, faster computers, HandBrake will also offer Google's VP8 and VP9 encoders. And both held up no matter what I threw at them, from animated movies to black-and-white classics to films with lots of fast action and bright colors. In my tests, both H.264 and HEVC looked remarkably close to the original, even on a big TV screen. Older Macs can play HEVC files just fine, but only the newest models have chips fast enough to encode HEVC decently.

If you don't have a Mac made from 2017 onward, stick with H.264. H.265 or HEVC makes files even smaller - but requires hefty processing power to crunch the necessary numbers. Tried-and-true H.264 converts relatively quickly, and it can squeeze a high-def Blu-ray file onto a DVD's worth of space or less. The first two aren't worth considering with the latter two available. HandBrake offers a choice of four compression algorithms: MPEG-2 (oldest, relatively lousy), MPEG-4 (still old, not great), H.264 (old, faster, pretty good), and HEVC/H.265 (new, slower, even better). HEVC: Which compression algorithm is best? Let's discuss a couple of the choices you'll need to weigh before you start putting your videos through the wringer.

Handbrake for compressing video