Introducing Daala, part 3: Time/Frequency Resolution Switching

[xiphmont]

I've just posted part 3 in my demo series introducing the Daala video codec. This one is kind of a long one, mainly because I think it's one of the only really detailed presentations of a technique Jean-Marc Valin of Xiph invented and first introduced in the Opus audio codec: 'TF' aka Time/Frequency resolution switching.

Even better... while I was documenting TF for posterity, I spotted a possible improvement. So, I've tossed in documentation of a brand new technique as well!

Comments

Re: TF merge speedups

[xiphmont.livejournal.com]

It can be used in either direction to gain speed over the DCT; however, there's a coding gain penalty.

As we're finding out, though, coding gain is not the end of the story (more about that later ;-)