+ * This determines and opens the next audio file, verifies that it did not
+ * change by comparing the recomputed the hash value of the file contents
+ * against the value stored in the audio file table. If all goes well, it
+ * creates a shared memory area containing the serialized version of the afd
+ * structure, including the chunk table, if any. The caller can then send the
+ * ID of this area and the open fd to the server process.
+ *
+ * \param fd Result pointer for the file descriptor of the audio file.