[mikeash]

My mistake, I must have been going off what's common versus what's allowed. Thanks for pointing it out.

[dunham]

Apple's jpeg animation hack used 4:4:4 so the blocks wouldn't interfere with each other. It's a neat hack, worth reading about if you haven't seen it yet: https://docs.google.com/document/pub?id=1GWTMLjqQsQS45FWwqNG...

[mikeash]

Holy moly. What a hack.