include: add AMR definitions in amr.h header

As defined by RFC3267 in Octed-Aligned mode.

1 files changed, 65 insertions, 0 deletions

diff --git a/include/osmocom/netif/amr.h b/include/osmocom/netif/amr.h
new file mode 100644
index 0000000..7a48923
--- /dev/null
+++ b/include/osmocom/netif/amr.h
@@ -0,0 +1,65 @@
+#ifndef _OSMO_AMR_H_
+#define _OSMO_AMR_H_
+
+/* As defined by RFC3267: Adaptive Multi-Rate (AMR) */
+
+/*
+ *  +----------------+-------------------+----------------
+ *  | payload header | table of contents | speech data ...
+ *  +----------------+-------------------+----------------
+ */
+
+/*
+ * 4.4. Octet-aligned Mode:
+ *
+ * 4.4.1. The Payload Header:
+ *
+ *   0 1 2 3 4 5 6 7
+ *  +-+-+-+-+-+-+-+-+
+ *  |  CMR  |X X X X|
+ *  +-+-+-+-+-+-+-+-+
+ *
+ * According to: 3GPP TS 26.201 "AMR Wideband speech codec; Frame Structure",
+ * version 5.0.0 (2001-03), 3rd Generation Partnership Project (3GPP):
+ *
+ * Possible AMR-CMR values:
+ *
+ * 0-8 for AMR-WB (from 6.60 kbit/s to 23.85 kbit/s)
+ * 9 (SID) confort noise.
+ * 10-13 future use.
+ * 14 means lost speech frame (only available for AMR-WB)
+ * 15 means no data
+ *
+ * 4.4.2. The table of contents:
+ *
+ *   0 1 2 3 4 5 6 7
+ *  +-+-+-+-+-+-+-+-+
+ *  |F|  FT   |Q|X X|
+ *  +-+-+-+-+-+-+-+-+
+ *
+ * X means padding.
+ */
+
+struct amr_hdr {
+#if __BYTE_ORDER == __BIG_ENDIAN
+	/* Payload Header */
+	uint8_t cmr:4,	/* Codec Mode Request */
+		pad1:4;
+	/* Table of Contents */
+	uint8_t f:1,	/* followed by another speech frame? */
+		ft:4,	/* coding mode */
+		q:1,	/* OK (not damaged) at origin? */
+		pad2:2;
+#elif __BYTE_ORDER == __LITTLE_ENDIAN
+	/* Payload Header */
+	uint8_t pad1:4,
+		cmr:4;
+	/* Table of Contents */
+	uint8_t pad2:2,
+		q:1,
+		ft:4,
+		f:1;
+#endif
+};
+
+#endif