If you mean the orthonormal transforms I read somewhere they were dropped because they were brought in too late and hardware would have to redesign a lot risking potential delays. Maybe they will make it for AV2.
@@Ashtree81 I don't know if this is an orthonormal transform, but it's a special kind of lifting scheme with a little post-adjustments to make it resemble a DCT, & it only used adds subs & small shifts to achieve that - & it wasn't brought in late, it was there from rather early on (it's already described in Monthy's first daala demo page) but it got dropped late in development. Also I see no way how this could be difficult to implement in hardware because it's fundamentally simpler than a DCT on so many levels: people.xiph.org/~xiphmont/demo/daala/demo1.shtml
