This seems like it's probably a stupid question, but I was wondering if there are still any legal considerations involved in using the JPEG format in one's projects. I've read all the previous threads I could find on the topic, and I gather that although there was a patent dispute at one point, the patent expired a while back and it's now ok to use the JPEG format without worrying about current or future legal entanglements. However, not being an expert on patent/IP law, I'm not sure if I'm interpreting the information correctly, and I certainly don't want to use the format if it could cause problems down the road. Would anyone be able to offer any clarification on this?

Quote:Original post by owl
given nowdays programs requirements and hardware capabilities, you could very well use a raw file image format, there is really no point anymore on compresing data if it's not going to be transmitted. You'd have to decompress it anyway to load it.

My motivation for using the JPEG format is to minimize the download size of the project (which, if it ends up being distributed, will be distributed over the internet).

It's not that big of a deal (using PNG instead won't increase the download size that much), but if JPEG is in fact a viable option, I'd like to be able to make use of it.

Quote:Original post by owl
I suppose you're going to distribute the program in a single compressed file. If the compression is good enough there should be really no difference. Probably the size of the library you would have to use to load the JPG into your program.

Heh. owl, zip up ten megs of TIFF files, then zip up the equivalent JPEGs plus a JPEG loader and get back to us.

Jyk, I don't know of any company making serious patent claims against the use of JPEG files in games. Obviously you can never be totally safe with these things, but IMO there's nothing to be concerned about. JPEG is certainly common in games, though you should also take a look at S3TC, which may be more suitable for your purposes.

Quote:Original post by owl
given nowdays programs requirements and hardware capabilities, you could very well use a raw file image format, there is really no point anymore on compresing data if it's not going to be transmitted. You'd have to decompress it anyway to load it.

I'm sure there are cases where it would come out about the same. I'm sure there are also cases where using JPEG would be a win. In any case, I think minimizing download size is a reasonable goal for a game that's intended to be distributed online (in that the fewer potential obstacles you present to the end user, the better).

Thanks all for the feedback (I'll look into the alternate formats suggested as well).

Can't you use PGF file format instead of JPEG? It has a better compression ration that jpeg, it supports 32 bit pixel format and it seems to be patent free.

Quote:I said a good compression. Using 7zip and 100% quality JPGs (because TIFFs are 100% quality) the difference is negligible, less than 100k.

Using 100% quality JPEGs would kind of defeat the purpose, no?

My informal observation (just based on saving images in various formats using the GIMP) is that JPEG files at maximum quality are the same size or larger than the equivalent PNG, while at the default quality (85), they're considerably smaller. This is entirely unscientific of course (for one thing, it depends on the image content), but nevertheless I'm not sure what the point of comparing the JPEG format to other formats is if you're going to use the maximum quality settings.

Anyway, there are really two different issues here: whether there's any legal risk involved in using JPEGs, and whether there's anything to be gained by using JPEGs. Your argument seems to be that, with respect to the latter point, the answer is no. I'm not really prepared to refute this argument without first gathering a significant amount of data regarding compression ratios, executable and library sizes, and download speeds, so I'll let it rest for now. I do think it's important to point out though that using 100% quality JPEGs is somewhat counter to the goal, which is to decrease file sizes at the (presumably acceptable) expense of image quality.