-void speaker_send(int fd, const struct speaker_message *sm, int datafd);
-/* Send a message. DATAFD is passed too if not -1. Does not close DATAFD. */
-
-int speaker_recv(int fd, struct speaker_message *sm, int *datafd);
-/* Receive a message. If DATAFD is not null then can receive an FD. Return 0
- * on EOF, +ve if a message is read, -1 on EAGAIN, terminates on any other
- * error. */
+/** @brief Speaker process is ready
+ *
+ * This is sent once at startup when the speaker has finished its
+ * initialization. */
+#define SM_READY 132
+
+void speaker_send(int fd, const struct speaker_message *sm);
+/* Send a message. */
+
+int speaker_recv(int fd, struct speaker_message *sm);
+/* Receive a message. Return 0 on EOF, +ve if a message is read, -1 on EAGAIN,
+ * terminates on any other error. */
+
+/** @brief One chunk in a stream */
+struct stream_header {
+ /** @brief Number of bytes */
+ uint32_t nbytes;
+
+ /** @brief Frames per second */
+ uint32_t rate;
+
+ /** @brief Samples per frames */
+ uint8_t channels;
+
+ /** @brief Bits per sample */
+ uint8_t bits;
+
+ /** @brief Endianness */
+ uint8_t endian;
+#define ENDIAN_BIG 1
+#define ENDIAN_LITTLE 2
+#ifdef WORDS_BIGENDIAN
+# define ENDIAN_NATIVE ENDIAN_BIG
+#else
+# define ENDIAN_NATIVE ENDIAN_LITTLE
+#endif
+} attribute((packed));
+
+static inline int formats_equal(const struct stream_header *a,
+ const struct stream_header *b) {
+ return (a->rate == b->rate
+ && a->channels == b->channels
+ && a->bits == b->bits
+ && a->endian == b->endian);
+}