The preferred format for multimedia files is the Microsoft Resource Interchange File Format (RIFF). The RIFF format is based on a tagged-file structure using chunks identified by four-character codes. You can use the multimedia file I/O services to open, read, and write RIFF files the same way as you would any other type of file. You can also use the following functions to create chunks, convert characters and strings to four-character codes, and navigate between chunks in RIFF files:
mmioAscend
Ascends out of a RIFF file chunk to the next chunk in the file.
mmioCreateChunk
Creates a chunk in a RIFF file.
mmioDescend
Descends into a RIFF file chunk starting at the current file position, or searches for a specified chunk.
mmioFOURCC
Converts four individual characters into a FOURCC code.
mmioStringToFOURCC
Converts a NULL-terminated string into a FOURCC code.