I am developing an iPad app that, among other things, plays MIDI files. My programmer found some free instrument sample audio files, and explained to me that to play an instrument sound the app takes a sample file (a short audio file like a wav, aiff, or caf file), transposes it into the correct key, and then plays it for the requested duration. He explained that to get the right duration, the sampler needs to loop parts of the file, but normally it shouldn't loop the whole file, but only a region in the middle of the file. Thus, the sampler needs to know which region to loop. He explained that wav, aiff, and caf files all provide the means to embed looping information. He has been looking for royalty-free instrument sample audio files with embedded looping info, but he hasn't found any. I'd be grateful if someone could point me to such files, or if there are no such royalty-free files, then to a library that we can license for distribution with our app. Thanks!