[dralley]

My point is, it's already possible to use multiple independently compressed (and decompressable) frames with zstd if you really want to.

It's even in the zstd repo, under a "contrib" implementation

https://github.com/facebook/zstd/blob/87af5fb2df7c68cc70c090...

That does, of course, require that you compress it into multiple frames to begin with, which could be a problem if you don't control the source of the compressed files, because the default is a single frame. In theory if everyone used pzstd to compress their files, it would be strictly superior to BZ2 in nearly every circumstance. As it is, you do have to go out of your way to do that.

But I don't think that necessarily means the single-frame choice by default is a bad tradeoff. It's better in most circumstances. And if they do eventually figure out a reasonably efficient way to handle intra-frame parallel decompression, then it's just gravy.