> That sounds way less awesome, when you consider it only had 256 colors, so allmost all content did indeed loose a lot, by converting to gif.
Nonlossy can be used for pixel perfect animations, lossy formats cannot.
> Because file size matters usually much more, than pixel perfect animation.
It depends. For video, that is true. For user interface, any glitch is distracting. Using JPEG for user interface images like buttons is in most cases a bad idea. Each format is useful in different situations.
> I wanted to convert a short screencast to a gif, result: hundreds of megabyte big monster, with crappy quality.
You are right, that is not a use case for GIF or equivalent formats.
I suspect you could use JPEG as a lossless format, you'd just have to write your own custom encoder.
In some sense, JPEG is just a really weird programming language. So a JPEG file is just a really weird program that gets interpreted by a JPEG decoder. Most normal JPEG encoders try to find a short 'program' in the 'JPEG programming language' that gets interpreted by the decoder to recreate a particular image reasonably well.
But there's no reason you couldn't ask for a perfect reproduction.
As far as I know, JPEG decoders are lossless and deterministic.
Of course, you point still stands that JPEG is not a good file format for storing UI elements. Even if in theory you could torture the JPEG standard enough to make this barely work.
"You are right, that is not a use case for GIF or equivalent formats. "
It is not, but this was still the main use case of gif - sharing short video sequences.
With crappy quality, but it played everywhere.
Apng is not the successor to that. Webm is, or will be.
So there might be niche cases in UI or games, where apng might make sense, but in most cases, I doubt people would see a difference between apng and webm - but they will notice faster or shorter loading times.
Nonlossy can be used for pixel perfect animations, lossy formats cannot.
> Because file size matters usually much more, than pixel perfect animation.
It depends. For video, that is true. For user interface, any glitch is distracting. Using JPEG for user interface images like buttons is in most cases a bad idea. Each format is useful in different situations.
> I wanted to convert a short screencast to a gif, result: hundreds of megabyte big monster, with crappy quality.
You are right, that is not a use case for GIF or equivalent formats.