[userbinator]

It splits the input into adaptively-sized blocks (quanta), runs a competition between many specialized codecs on each block, and emits the smallest result.

This is, for lack of a better term, a "metacompressor", but it will be interesting to see which of the choices end up dominating; in my past experiences with metacompression, one algorithm is usually consistently ahead.

[enduku]

That’s a fair description. One mode does not dominate in my current harness; the winning mode varies quite a bit by dataset/block. If real workloads show one or two modes dominate, I’d rather simplify the portfolio :) For now the extra encode CPU is intentional: spend time once, get smaller blocks and fast parallel decode.

[apodik]

I’ve never heard of a metacompressor before, what others exist?

[whizzter]

I think the idea is that the compressor is "meta" in the sense that it directs compressors as GP mentions by selecting what's actually producing the best results, so it's not just one comrpessor but a series of supported ones plugged in to be used adaptively (controlled at a "meta" level).

Floating point data is a mess to compress, but I think the idea here is to apply different transforms (and perhaps back-end codecs) on data and see if one fits the data so perfectly that you magically get a lot of compression.

Say you have an audio with a sawtooth, it's linear an gradient but if the peaks is "random" values like 1.245 and PI then the mantissa bits of the interpolation range will look fairly "random" to a classic compressor, whilst this compressor can test to see if there are linear gradient spans (or near linear gradient) where it stores the gradient and dumps out the "difference" bits for a regular compressor.

Or 3d coordinates for 3d models (non-stripified), plenty of repeating 8-byte doubles that will be garbage and not help a classic compressor much, building a float aware dictionary and using that would easily bring down the data by quite a few %.

(I don't agree with GP, one method might win out for certain workloads, but the idea here seems to be a pluggable utility that can help a wide range of developers with something "for free").

[CyberDildonics]

Even back when star wars episode 1 came out with quicktime files of the trailer there were multiple codecs used in the same video file to make it look as good as possible.

Making up a new term isn't necessary, this has been done and everyone just called it compression.

[enduku]

I’m regarding that term loosely here- in this case it is 'try several representations/codecs for a block and store the winner.' Similar ideas show up in columnar formats choosing encodings per column/page, OpenZL selectors (asother commenters pointed here), and shuffle/transpose + backend-compressor pipelines. fc’s version is much narrower: a tournament among f64-specific modes per block.