I wasn't around when the name for this project was chosen (I only got involved after the call for proposals, at which point the codec already had a name even if it didn't exist yet). I haven't been able to track down the actual etymology or rationale for the name, though "Long-term" has been suggested to be the main interpretation.
I think the name was to some extent chosen as a tongue-in-cheek pun because obviously compression is about making large things smaller. The name must have been chosen around the time that there was a lot of activity around JPEG XS. That codec is all about speed and low complexity, which is where the S comes from: it is very fast (so S for speed) and also it has a relatively simple and small implementation (in terms of circuit complexity), since it is designed for hardware.
So in contrast to JPEG XS, JPEG XL is actually "extra large" in the sense that it does have more complexity, more coding tools, more functionality. All those things are of course there with the goal of making smaller files, but the codec itself is "extra large" compared to JPEG since it has all the coding tools of JPEG plus a bunch more. So in that sense, JPEG XS is indeed "extra small" and JPEG XL is "extra large", as a codec, but in terms of the sizes of the compressed images, it's exactly the other way around: JPEG XS will produce larger files (it sacrifices compression for simplicity/speed/latency), JPEG XL will produce smaller files.
I agree that all this is quite confusing. If it helps, you can always just call it by its filename extension / media type instead of its full name: "jxl".
I wasn't around when the name for this project was chosen (I only got involved after the call for proposals, at which point the codec already had a name even if it didn't exist yet). I haven't been able to track down the actual etymology or rationale for the name, though "Long-term" has been suggested to be the main interpretation.
I think the name was to some extent chosen as a tongue-in-cheek pun because obviously compression is about making large things smaller. The name must have been chosen around the time that there was a lot of activity around JPEG XS. That codec is all about speed and low complexity, which is where the S comes from: it is very fast (so S for speed) and also it has a relatively simple and small implementation (in terms of circuit complexity), since it is designed for hardware.
So in contrast to JPEG XS, JPEG XL is actually "extra large" in the sense that it does have more complexity, more coding tools, more functionality. All those things are of course there with the goal of making smaller files, but the codec itself is "extra large" compared to JPEG since it has all the coding tools of JPEG plus a bunch more. So in that sense, JPEG XS is indeed "extra small" and JPEG XL is "extra large", as a codec, but in terms of the sizes of the compressed images, it's exactly the other way around: JPEG XS will produce larger files (it sacrifices compression for simplicity/speed/latency), JPEG XL will produce smaller files.
I agree that all this is quite confusing. If it helps, you can always just call it by its filename extension / media type instead of its full name: "jxl".