This bit > What makes QOA work is 1) a reasonably good predictor and 2) storing the scalefactor for a bunch of samples explicitly instead of guessing the right

This bit > What makes QOA work is 1) a reasonably good predictor and 2) storing the scalefactor for a bunch of samples explicitly instead of guessing the right one from context, like ADPCM does. suggests a comparison with DVI/IMA ADPCM [1] or derivatives, which go out of their way not to have too much state or use multiplies, and they also tend to be used at really low bitrates, so they have a somewhat deserved bad reputation. "Guessing" the scalefactor is overstating it, the scale does dynamically adjust but that's all considered from the encoder. The 2-history-samples style ADPCMs in the BRR [2] family usually have very short frames (at most dozens of samples) and headers specifying scale and predictor/filter index. I know a lot more about what's used on consoles than about the math of audio encoding, though, so I can't say whether QOA is making the wrong tradeoffs. [1] https://wiki.multimedia.cx/index.php/IMA_ADPCM https://wiki.multimedia.cx/index.php/IMA_ADPCM [2] https://en.wikipedia.org/wiki/Bit_Rate_Reduction https://en.wikipedia.org/wiki/Bit_Rate_Reduction