[Lerc]

JPEG is the go-to format for showing your compression is better at high compression rates because once you get past a certain point you don't have enough data for coefficients and JPEG ends up storing most of it as flat 8x8 blocks.

It's not representative of the performance of JPEG becasue You typically don't encode JPEGs at that bit rate.

It's basically taking advantage of the fact that JPEG dips first. http://article.sapub.org/image/10.5923.j.ajsp.20120205.04_01...

Also be wary of things that report compression rates rather than bits-per-pixel. You can get the same image quality at 200:1 if you start with 48 bit colour, The bits per pixel would be the same but if your original data is excessively precise you can throw a lot of it away at no perceptible cost.

[camkego]

Good point about bits per pixel.