Why can't we upload JP2 files that aren't modified?

Images file we upload are converted to JP2 files with each dimension being resized to a power of two.

Why aren't we able to upload files that we have already made into JP2 files with appropriate power of two sizes that don't get altered when uploaded?

Ummm... Because 5 years oe so ago when LL devised how texture importing was to work, none of them had ever seen a graphics app on a home PC that used JP2 format? And since then, the only real change they have made was to allow PNG files to be imported?

Makes sense to me that we should be able to do a lossless import of a JP2 file, provided it was in a correct power of two size ratio. But things that make sense to sensible people rarely seem to make sense to LL.

the problem may not be in the *upload* actually. Best anyone at LL can guess (please don't make me go searching thru the jira for the quote) the texture *download* assumes all jp2s have an 8:1 compression ratio. So if your tex is overly complex it won't hit that mark. Which means, the highest level of detail never gets fully downloaded. In "some" (many/all?) cases, it never gets downloaded fully even after a client retry. So what you see in the client is always a little borky. There's no way to tell for certain what's actually on the server.

A little gadget I was working on required upload of 12MB to even be close to something a simple BMP+RLE stored in 130K.

There's another concern besides just the dimensions. The compression scheme on the source file would need to be the same one SL would have used for the equivalent texture, had it done the JPEG2000 conversion itself. Otherwise, people would end up uploading files that are way too big for SL purposes. We certainly wouldn't want people uploading losslessly compressed 1024x1024's, for example.

That said, I do agree in principle that it's pretty silly we've never been able to import JPEG2000's directly, considering it would save the work of converting at the time of upload. But I don't think expanding the file format list is real high on LL's priority list. Heck, we only got PNG because a resident stepped up and wrote the code for it. Anyone want to do the same for PSD?

Because if you could, thieves could intercept the JP2 files when they're sent to the client and re-upload them perfectly with their names on them. At the moment, no matter how a thief extracts a texture, it will suffer some quality loss from being re-compressed.

Tga is lossless anyway... so when converted in jp2 it's probably as good as it will get.