On Fri, 1 Dec 2006, Sven Panne wrote:
I don't have any Haskell lib for (R)IFF, but as one of the freealut authors I have the "pleasure" to maintain a WAV reader, among other things. IMHO WAV is one of the most idiotic, redundant and underspecified format in the world, and most existing WAV files are broken in some respect. PNGs are a bit better, but all those chunked formats are a bit problematic in practice, because new chunk types are constantly being invented, contradict other chunks, etc. etc.
The idea is that unknown chunks can be ignored in most cases. Of course, this is not always possible, but there are several examples where it worked.
Quite a few concrete (R)IFF instances can contain (R)IFF within chunks themselves, furthermore you have always be prepared to handle an unknown chunk type. So a general (R)IFF type can't be much more than a tree with a tagged bunch of bytes at each node, which is not really of much help IMHO.
That's exactly what I ask for. Some of the features of the IFF like CAT and PROP chunks are rarely used, maybe because there were no libraries which support them.
Separate libraries for handling WAV, TIFF, PNG, AVI, etc. might make more sense, as they can reflect the underlying structure much better.
But they could all use a general IFF library. This way you can bundle different kinds of data in one file, say sounds and pictures for an animation.