+/** \file mp4.h Public API of the mp4 parser. */
+
+/**
+ * Callbacks provided by the user of the mp4 parsing API.
+ *
+ * A pointer to this structure is passed to the two public open functions. If
+ * the file is opened in read-only mode, the ->write() and ->truncate() methods
+ * won't be called and may thus be NULL. The ->read() and ->seek() methods
+ * must be supplied for either open type.
+ *
+ * All methods are supposed to work like their corresponding system calls.
+ * That is, they should return non-negative for success and -1 on failure. In
+ * the error case errno is expected to be set accordingly.
+ *
+ * \sa \ref mp4_open(), \ref mp4_open_meta().
+ */