Hello to all. I want to know what are the loop music formats exist(maybe they called circular). I mean, the same track goes in loop withot any dilays in the middle. (I think that this what was used in older cartrige-based game consoles).

This can be done with almost any format. You simple ensure that the end and beginning of the file matches up, and restart the file as soon as it reaches the end. Some common formats that may have been used include .mod and midi.

If you're looking for a small, loopable format to use in a project (especially if you're after a retro feel), then the mod format may be what you're looking for. You can create and edit mod files with Modplug Tracker (among other programs), which is freeware and can be found at www.modplug.com.

You could also use other formats, such as wave (filesize is pretty big though), ogg, or mp3 (requires licencing), or perhaps midi.

Thanks :)