[dbaupp]

Ah, it is a good point that it might be worth comparing to, but it is far worse.

Abstractly, it requires approximately log(45)/log(16) output bits per input bit, an overhead of 37%.

Making this more concrete: each input byte is encoded as two hex digits, and two hex digits have to be encoded as two Alphanumeric characters. It thus takes 11 bits in the QR code bit stream to store 8 bits of input.

[dbaupp]

(I've added an analysis of this and other bases to the article: https://huonw.github.io/blog/2024/03/qr-base10-base64/#fn:ot...)

[Zamicol]

RFC 3986 says that * is a sub-delim. It cannot be assumed to be URI safe.

A base 38 alphabet is the maximal possible URI unreserved alphabet.