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My first technical writing regarding the new AV1 codec is up at Xiph.Org. We've been working on AV1, heads-down, for a long time and my writing took a hiatus for almost that entire period. Now that it's out, it's time to continue the technology pages that I started with Daala.

"AV1 is a new general-purpose video codec developed by the Alliance for Open Media. The alliance began development of this new codec using Google's VPX codecs, Cisco's Thor codec, and Mozilla's/Xiph.Org's Daala codec as starting point. AV1 leapfrogs the performance of VP9 and HEVC, making it a next-next-generation codec. The AV1 format is and will always be royalty-free with a permissive FOSS license."

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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!

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I've made another demo page, this one in celebration of the Opus 1.1 beta release today...

"Opus marches onward toward its manifest destiny with today's beta of the upcoming 1.1 release. This will be the first major update to libopus since standardization as RFC 6716 in 2012, and includes improvements to performance, encoding quality, and the library APIs. Here's a few of the upgrades that Opus users and implementors will care about the most."

Cheers!

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I'd mentioned in the previous update that we're (Xiph is) using a chirp estimation algorithm that we published back in 2007, and that the original paper has precious little space to devote to describing in detail how the algorithm actually performed. One of the upshots of not having done extensive characterization tests of our own algorithm was that it has already surprised me a few times this year (in both good and bad ways).

Therefore, Ghost Update 20110604 concerns itself with describing and graphing algorithm behavior in mind-numbing detail.

Death! By! Graphs!

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