From 2753cdfc7c3574a2d32f5b251cb857027074d3d7 Mon Sep 17 00:00:00 2001
From: "Alfred E. Heggestad" <aeh@db.org>
Date: Sun, 14 Jun 2015 12:05:01 +0200
Subject: amr: add support for octet-align mode

- this fixes compliance with RFC 4867
- this will break interop with older versions of baresip
- Bandwidth-Efficient Mode can be added later

fixes issue #37
---
 modules/amr/amr.c     | 30 ++++++++++++++++++---------
 modules/amr/amr.h     | 10 +++++++++
 modules/amr/module.mk |  2 +-
 modules/amr/sdp.c     | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+), 10 deletions(-)
 create mode 100644 modules/amr/amr.h
 create mode 100644 modules/amr/sdp.c

(limited to 'modules/amr')

diff --git a/modules/amr/amr.c b/modules/amr/amr.c
index 1e698d1..74e353a 100644
--- a/modules/amr/amr.c
+++ b/modules/amr/amr.c
@@ -17,6 +17,7 @@
 #endif
 #include <re.h>
 #include <baresip.h>
+#include "amr.h"
 
 
 #ifdef VO_AMRWBENC_ENC_IF_H
@@ -25,10 +26,15 @@
 #endif
 
 
-/*
+/**
+ * @defgroup amr amr
+ *
  * This module supports both AMR Narrowband (8000 Hz) and
  * AMR Wideband (16000 Hz) audio codecs.
  *
+ * NOTE: only octet-align mode is supported.
+ *
+ *
  * Reference:
  *
  *     http://tools.ietf.org/html/rfc4867
@@ -209,11 +215,14 @@ static int encode_wb(struct auenc_state *st, uint8_t *buf, size_t *len,
 	if (*len < NB_SERIAL_MAX)
 		return ENOMEM;
 
-	n = IF2E_IF_encode(st->enc, 8, sampv, buf, 0);
+	/* CMR value 15 indicates that no mode request is present */
+	buf[0] = 15 << 4;
+
+	n = IF2E_IF_encode(st->enc, 8, sampv, &buf[1], 0);
 	if (n <= 0)
 		return EPROTO;
 
-	*len = n;
+	*len = (1 + n);
 
 	return 0;
 }
@@ -227,7 +236,7 @@ static int decode_wb(struct audec_state *st, int16_t *sampv, size_t *sampc,
 	if (len > NB_SERIAL_MAX)
 		return EINVAL;
 
-	IF2D_IF_decode(st->dec, buf, sampv, 0);
+	IF2D_IF_decode(st->dec, &buf[1], sampv, 0);
 
 	*sampc = L_FRAME16k;
 
@@ -247,11 +256,14 @@ static int encode_nb(struct auenc_state *st, uint8_t *buf,
 	if (*len < NB_SERIAL_MAX)
 		return ENOMEM;
 
-	r = Encoder_Interface_Encode(st->enc, MR475, sampv, buf, 0);
+	/* CMR value 15 indicates that no mode request is present */
+	buf[0] = 15 << 4;
+
+	r = Encoder_Interface_Encode(st->enc, MR122, sampv, &buf[1], 0);
 	if (r <= 0)
 		return EPROTO;
 
-	*len = r;
+	*len = (1 + r);
 
 	return 0;
 }
@@ -269,7 +281,7 @@ static int decode_nb(struct audec_state *st, int16_t *sampv,
 	if (*sampc < L_FRAME16k)
 		return ENOMEM;
 
-	Decoder_Interface_Decode(st->dec, buf, sampv, 0);
+	Decoder_Interface_Decode(st->dec, &buf[1], sampv, 0);
 
 	*sampc = FRAMESIZE_NB;
 
@@ -283,7 +295,7 @@ static struct aucodec amr_wb = {
 	LE_INIT, NULL, "AMR-WB", 16000, 1, NULL,
 	encode_update, encode_wb,
 	decode_update, decode_wb,
-	NULL, NULL, NULL
+	NULL, amr_fmtp_enc, amr_fmtp_cmp
 };
 #endif
 #ifdef AMR_NB
@@ -291,7 +303,7 @@ static struct aucodec amr_nb = {
 	LE_INIT, NULL, "AMR", 8000, 1, NULL,
 	encode_update, encode_nb,
 	decode_update, decode_nb,
-	NULL, NULL, NULL
+	NULL, amr_fmtp_enc, amr_fmtp_cmp
 };
 #endif
 
diff --git a/modules/amr/amr.h b/modules/amr/amr.h
new file mode 100644
index 0000000..6746a83
--- /dev/null
+++ b/modules/amr/amr.h
@@ -0,0 +1,10 @@
+/**
+ * @file amr/amr.h AMR module -- internal interface
+ *
+ * Copyright (C) 2010 - 2015 Creytiv.com
+ */
+
+
+int  amr_fmtp_enc(struct mbuf *mb, const struct sdp_format *fmt,
+		  bool offer, void *arg);
+bool amr_fmtp_cmp(const char *lfmtp, const char *rfmtp, void *arg);
diff --git a/modules/amr/module.mk b/modules/amr/module.mk
index cbe1013..4f8ecdf 100644
--- a/modules/amr/module.mk
+++ b/modules/amr/module.mk
@@ -5,7 +5,7 @@
 #
 
 MOD		:= amr
-$(MOD)_SRCS	+= amr.c
+$(MOD)_SRCS	+= amr.c sdp.c
 
 
 ifneq ($(shell [ -d $(SYSROOT)/include/opencore-amrnb ] && echo 1 ),)
diff --git a/modules/amr/sdp.c b/modules/amr/sdp.c
new file mode 100644
index 0000000..e4b0cdf
--- /dev/null
+++ b/modules/amr/sdp.c
@@ -0,0 +1,56 @@
+/**
+ * @file amr/sdp.c AMR SDP Functions
+ *
+ * Copyright (C) 2010 - 2015 Creytiv.com
+ */
+
+#include <re.h>
+#include <baresip.h>
+#include "amr.h"
+
+
+static bool amr_octet_align(const char *fmtp)
+{
+	struct pl pl, oa;
+
+	if (!fmtp)
+		return false;
+
+	pl_set_str(&pl, fmtp);
+
+	if (fmt_param_get(&pl, "octet-align", &oa))
+		return 0 == pl_strcmp(&oa, "1");
+
+	return false;
+}
+
+
+int amr_fmtp_enc(struct mbuf *mb, const struct sdp_format *fmt,
+		 bool offer, void *arg)
+{
+	const struct aucodec *ac = arg;
+	(void)offer;
+
+	if (!mb || !fmt || !ac)
+		return 0;
+
+	return mbuf_printf(mb, "a=fmtp:%s octet-align=1\r\n",
+			   fmt->id);
+}
+
+
+bool amr_fmtp_cmp(const char *lfmtp, const char *rfmtp, void *arg)
+{
+	const struct aucodec *ac = arg;
+	(void)lfmtp;
+
+	if (!ac)
+		return false;
+
+	if (!amr_octet_align(rfmtp)) {
+		info("amr: octet-align mode is required\n");
+		return false;
+	}
+
+	return true;
+}
-- 
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