Daala is a concept video encoder that Xiph and Mozilla are hoping will make an end run around HEVC (the successor to H.264/AVC). Monty Montgomery has a brilliantly-written 4-part intro to Daala’s core ideas. It’s probably tough to follow if you haven’t read much about video codecs before so here are a few of the highlights:
* They’ve found a clever & efficient way around the blockiness of nearly every frame encoder in common used (JPEG through AVC) by overlapping the blocks and leveling them in the frequency domain
* They have a fast technique for predicting colors from the brightness (jargon: predicting the chroma planes from the luma plane) which will likely be used to get better color fidelity from fewer bytes. The downside is a possible loss of parallelism in the encoder and decoder (my speculation: but maybe not with some careful pipelining)
* By focusing attention on the frequency domain, they’re avoiding a several patents in spatial compression, which potentially helps Mozilla’s roadmap
If 420 makes you think YUV instead of legalization, then I highly recommend reading these 4 articles.