proposal: image/jpeg: add support for arithmetic encoding

[robert-ancell]

Proposal Details

JPEG supports two forms of entropy coding, Huffman and Arithmetic. Due to patent concerns, most implementations (at least on the Internet) made use of Huffman coding, however many implementations including the standard libjpeg have now supported Arithmetic coding for many years. I propose updating the Go JPEG implementation to support Arithmetic coding.

[robert-ancell]

I'd like to implement this feature, I just want to check first if this is considered suitable for the Go implementation.

[seankhliao]

cc @nigeltao

[nigeltao]

It'd be a new feature to an existing standard library package (image/jpeg), not a new standard library package, but Why isn’t X in the standard library? from the official FAQ still says:

New additions to the standard library are rare and the bar for inclusion is high...

Most new code should live outside of the standard library and be accessible via the go tool’s go get command. Such code can have its own maintainers, release cycle, and compatibility guarantees.

I would recommend forking the image/jpeg package and adding arithmetic support, in your own package outside of the standard library. Publish it on GitHub or elsewhere. If it gets a lot of use, I would then consider upstreaming it into the stdlib. But, until then, I'm wary of adding to the stdlib maintenance burden.

[robert-ancell]

Thanks for the response - I'll look into building my own package. Not sure what the issue tracking process here is, feel free to close if appropriate.