About Multimedia File I/O

[The feature associated with this page, Multimedia File I/O, is a legacy feature. It has been superseded by Source Reader. Source Reader has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader instead of Multimedia File I/O, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Most multimedia applications require file input and output (I/O) — that is, the ability to create, read, and write disk files. Multimedia file I/O services provide buffered and unbuffered file I/O and support for RIFF files. The services are extensible with custom I/O procedures that can be shared among applications.

Most applications need only the basic file I/O services and the RIFF file I/O services. Applications sensitive to file I/O performance, such as applications that stream data from compact disc in real time, can optimize performance by using services to directly access the file I/O buffer. Applications that access custom storage systems, such as file archives and databases, can provide their own I/O procedure that reads and writes elements of the storage system.