Intergalacticdespot t1_ixxtf8s wrote on November 27, 2022 at 5:25 AM

Reply to comment by Fluffy-Jackfruit-930 in ELI5: In recent years, new formats like webp and jfif have started popping up. However, if I rename them to gif or jpeg, they still work. How can it be that renaming the extension doesn't ruin the image format? Why do they even exist then? by Luthemplaer

Technically whichever company invented jpeg owns all pictures encoded as .jpeg. I'd imagine it wouldn't hold up in court because it's been unenforced for like 20-30 years now. But in theory jpeg itself is the same way. Was one of the earliest mass copyright attempts. And why I still prefer gif or png when at all possible.

Fluffy-Jackfruit-930 t1_ixzf36g wrote on November 27, 2022 at 4:22 PM

JPEG was developed by the Joint Photographic Experts Group and the CCITT, with the intention of being a free and open standard. Where they did use patented technology, they specifically negotiated with the patent holders to get free use rights.

Lossless JPEG, in particular, used a ton of patented technology, whereas lossy JPEG was pretty much patent-free. Some lawyers were concerned that the agreements may be CCITT/JPEG might not cover all patents, so lossless JPEG was immediately hamstrung by legal concerns, plus the fact that for most purposes, lossy JPEG was plenty good enough and gave much better compression.

There was a bit of a controversy, because in 2002, a company with a patent on the DCT technology behind lossy JPEG, suddenly started instructing lawyers to sue any company using JPEG files or using software which could handle JPEG files. This patent wasn't listed in the legal documents produced by JPEG/CCITT, so they didn't have a legal agreement in place. In the end, the company decided to drop the claims, because the patent wasn't actually valid.

GIF has also been problematic from a patent and legal perspective, although PNG has been designed from the ground up to be open and avoid patented technologies completely.