18 ms·

Nope. X265/HEVC https://en.m.wikipedia.org/wiki/High_Efficiency_Video_Coding https://en.m.wikipedia.org/wiki/High_Efficiency_Video_Coding Also not true for X2

by mbtwl 2y ago

Nope. X265/HEVC https://en.m.wikipedia.org/wiki/High_Efficiency_Video_Coding https://en.m.wikipedia.org/wiki/High_Efficiency_Video_Coding Also not true for X266/VVC.

aidenn0 2y ago
AV1 also uses DCT and DST, but not Hadamard.
- derf_ 2y ago
  Technically, AV1 also uses Hadamard in the lossless modes.
  - aidenn0 2y ago
    Thanks for the correction, I didn't know that.
kappi 2y ago
correct, it is integer DCT. Lot of techniques adopted from the integer transform of H.264. That's what I meant, not the floating point DCT proposed in 70s.
- Sesse__ 2y ago
  The big change is basically that we now typically specify exactly which integer approximation to the (real-valued, “ideal”) DCT to use; this means the decoder and encoder is much likely to fall out of sync. As a bonus, this means we can use a slightly worse but much faster approximation without catastrophes happening, and possibly also make it exactly invertible. https://fgiesen.wordpress.com/2013/11/04/bink-2-2-integer-dct-design-part-1/ https://fgiesen.wordpress.com/2013/11/04/bink-2-2-integer-dc... has a ton of technical information if you want to dive into it.