Add pass through support for Opus and VP8; Opus format attribute negotiation

This patch adds pass through support for Opus and VP8. That includes:

* Format attribute negotiation for Opus. Note that unlike some other codecs,
  the draft RFC specifies having spaces delimiting the attributes in addition
  to ';', so you have "attra=X; attrb=Y". This broke the attribute parsing in
  chan_sip, so a small tweak was also included in this patch for that.

* A format attribute negotiation module for Opus, res_format_attr_opus

* Fast picture update for VP8. Since VP8 uses a different RTCP packet number
  than FIR, this really is specific to VP8 at this time.

Note that the format attribute negotiation in res_pjsip_sdp_rtp was written
by mjordan. The rest of this patch was written completely by Lorenzo Miniero.

Review: https://reviewboard.asterisk.org/r/2723/

(closes issue ASTERISK-21981)
Reported by: Tzafrir Cohen
patches:
  asterisk_opus+vp8_passthrough_20130718.patch uploaded by lminiero (License 6518)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@397526 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 321 insertions, 0 deletions

diff --git a/res/res_format_attr_opus.c b/res/res_format_attr_opus.c
new file mode 100644
index 000000000..ed8adb77f
--- /dev/null
+++ b/res/res_format_attr_opus.c
@@ -0,0 +1,321 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * Lorenzo Miniero <lorenzo@meetecho.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \brief Opus format attribute interface
+ *
+ * \author Lorenzo Miniero <lorenzo@meetecho.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/module.h"
+#include "asterisk/format.h"
+
+/*!
+ * \brief Opus attribute structure.
+ *
+ * \note http://tools.ietf.org/html/draft-ietf-payload-rtp-opus-00.
+ */
+struct opus_attr {
+	unsigned int maxbitrate;	        /* Default 64-128 kb/s for FB stereo music */
+	unsigned int maxplayrate	        /* Default 48000 */;
+	unsigned int minptime;	            /* Default 3, but it's 10 in format.c */
+	unsigned int stereo;	            /* Default 0 */
+	unsigned int cbr;	                /* Default 0 */
+	unsigned int fec;	                /* Default 0 */
+	unsigned int dtx;	                /* Default 0 */
+	unsigned int spropmaxcapturerate;	/* Default 48000 */
+	unsigned int spropstereo;	        /* Default 0 */
+};
+
+static int opus_sdp_parse(struct ast_format_attr *format_attr, const char *attributes)
+{
+	struct opus_attr *attr = (struct opus_attr *) format_attr;
+	const char *kvp;
+	unsigned int val;
+
+	if ((kvp = strstr(attributes, "maxplaybackrate")) && sscanf(kvp, "maxplaybackrate=%30u", &val) == 1) {
+		attr->maxplayrate = val;
+	}
+	if ((kvp = strstr(attributes, "sprop-maxcapturerate")) && sscanf(kvp, "sprop-maxcapturerate=%30u", &val) == 1) {
+		attr->spropmaxcapturerate = val;
+	}
+	if ((kvp = strstr(attributes, "minptime")) && sscanf(kvp, "minptime=%30u", &val) == 1) {
+		attr->minptime = val;
+	}
+	if ((kvp = strstr(attributes, "maxaveragebitrate")) && sscanf(kvp, "maxaveragebitrate=%30u", &val) == 1) {
+		attr->maxbitrate = val;
+	}
+	if ((kvp = strstr(attributes, " stereo")) && sscanf(kvp, " stereo=%30u", &val) == 1) {
+		attr->stereo = val;
+	}
+	if ((kvp = strstr(attributes, ";stereo")) && sscanf(kvp, ";stereo=%30u", &val) == 1) {
+		attr->stereo = val;
+	}
+	if ((kvp = strstr(attributes, "sprop-stereo")) && sscanf(kvp, "sprop-stereo=%30u", &val) == 1) {
+		attr->spropstereo = val;
+	}
+	if ((kvp = strstr(attributes, "cbr")) && sscanf(kvp, "cbr=%30u", &val) == 1) {
+		attr->cbr = val;
+	}
+	if ((kvp = strstr(attributes, "useinbandfec")) && sscanf(kvp, "useinbandfec=%30u", &val) == 1) {
+		attr->fec = val;
+	}
+	if ((kvp = strstr(attributes, "usedtx")) && sscanf(kvp, "usedtx=%30u", &val) == 1) {
+		attr->dtx = val;
+	}
+
+	return 0;
+}
+
+static void opus_sdp_generate(const struct ast_format_attr *format_attr, unsigned int payload, struct ast_str **str)
+{
+	struct opus_attr *attr = (struct opus_attr *) format_attr;
+
+	/* FIXME should we only generate attributes that were explicitly set? */
+	ast_str_append(str, 0,
+				"a=fmtp:%d "
+					"maxplaybackrate=%d;"
+					"sprop-maxcapturerate=%d;"
+					"minptime=%d;"
+					"maxaveragebitrate=%d;"
+					"stereo=%d;"
+					"sprop-stereo=%d;"
+					"cbr=%d;"
+					"useinbandfec=%d;"
+					"usedtx=%d\r\n",
+			payload,
+			attr->maxplayrate ? attr->maxplayrate : 48000,	/* maxplaybackrate */
+			attr->spropmaxcapturerate ? attr->spropmaxcapturerate : 48000,	/* sprop-maxcapturerate */
+			attr->minptime > 10 ? attr->minptime : 10,	/* minptime */
+			attr->maxbitrate ? attr->maxbitrate : 20000,	/* maxaveragebitrate */
+			attr->stereo ? 1 : 0,		/* stereo */
+			attr->spropstereo ? 1 : 0,		/* sprop-stereo */
+			attr->cbr ? 1 : 0,		/* cbr */
+			attr->fec ? 1 : 0,		/* useinbandfec */
+			attr->dtx ? 1 : 0		/* usedtx */
+	);
+}
+
+static int opus_get_val(const struct ast_format_attr *fattr, int key, void *result)
+{
+	const struct opus_attr *attr = (struct opus_attr *) fattr;
+	int *val = result;
+
+	switch (key) {
+	case OPUS_ATTR_KEY_MAX_BITRATE:
+		*val = attr->maxbitrate;
+		break;
+	case OPUS_ATTR_KEY_MAX_PLAYRATE:
+		*val = attr->maxplayrate;
+		break;
+	case OPUS_ATTR_KEY_MINPTIME:
+		*val = attr->minptime;
+		break;
+	case OPUS_ATTR_KEY_STEREO:
+		*val = attr->stereo;
+		break;
+	case OPUS_ATTR_KEY_CBR:
+		*val = attr->cbr;
+		break;
+	case OPUS_ATTR_KEY_FEC:
+		*val = attr->fec;
+		break;
+	case OPUS_ATTR_KEY_DTX:
+		*val = attr->dtx;
+		break;
+	case OPUS_ATTR_KEY_SPROP_CAPTURE_RATE:
+		*val = attr->spropmaxcapturerate;
+		break;
+	case OPUS_ATTR_KEY_SPROP_STEREO:
+		*val = attr->spropstereo;
+		break;
+	default:
+		ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
+		return -1;
+	}
+	return 0;
+}
+
+static int opus_isset(const struct ast_format_attr *fattr, va_list ap)
+{
+	enum opus_attr_keys key;
+	const struct opus_attr *attr = (struct opus_attr *) fattr;
+
+	for (key = va_arg(ap, int);
+		key != AST_FORMAT_ATTR_END;
+		key = va_arg(ap, int))
+	{
+		switch (key) {
+		case OPUS_ATTR_KEY_MAX_BITRATE:
+			if (attr->maxbitrate != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_MAX_PLAYRATE:
+			if (attr->maxplayrate != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_MINPTIME:
+			if (attr->minptime != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_STEREO:
+			if (attr->stereo != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_CBR:
+			if (attr->cbr != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_FEC:
+			if (attr->fec != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_DTX:
+			if (attr->dtx != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_SPROP_CAPTURE_RATE:
+			if (attr->spropmaxcapturerate != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		case OPUS_ATTR_KEY_SPROP_STEREO:
+			if (attr->spropstereo != (va_arg(ap, int))) {
+				return -1;
+			}
+			break;
+		default:
+			ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
+			return -1;
+		}
+	}
+	return 0;
+}
+static int opus_getjoint(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2, struct ast_format_attr *result)
+{
+	struct opus_attr *attr1 = (struct opus_attr *) fattr1;
+	struct opus_attr *attr2 = (struct opus_attr *) fattr2;
+	struct opus_attr *attr_res = (struct opus_attr *) result;
+	int joint = 0;
+
+	/* Only do dtx if both sides want it. DTX is a trade off between
+	 * computational complexity and bandwidth. */
+	attr_res->dtx = attr1->dtx && attr2->dtx ? 1 : 0;
+
+	/* Only do FEC if both sides want it.  If a peer specifically requests not
+	 * to receive with FEC, it may be a waste of bandwidth. */
+	attr_res->fec = attr1->fec && attr2->fec ? 1 : 0;
+
+	/* Only do stereo if both sides want it.  If a peer specifically requests not
+	 * to receive stereo signals, it may be a waste of bandwidth. */
+	attr_res->stereo = attr1->stereo && attr2->stereo ? 1 : 0;
+
+	/* FIXME: do we need to join other attributes as well, e.g., minptime, cbr, etc.? */
+
+	return joint;
+}
+
+static void opus_set(struct ast_format_attr *fattr, va_list ap)
+{
+	enum opus_attr_keys key;
+	struct opus_attr *attr = (struct opus_attr *) fattr;
+
+	for (key = va_arg(ap, int);
+		key != AST_FORMAT_ATTR_END;
+		key = va_arg(ap, int))
+	{
+		switch (key) {
+		case OPUS_ATTR_KEY_MAX_BITRATE:
+			attr->maxbitrate = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_MAX_PLAYRATE:
+			attr->maxplayrate = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_MINPTIME:
+			attr->minptime = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_STEREO:
+			attr->stereo = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_CBR:
+			attr->cbr = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_FEC:
+			attr->fec = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_DTX:
+			attr->dtx = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_SPROP_CAPTURE_RATE:
+			attr->spropmaxcapturerate = (va_arg(ap, int));
+			break;
+		case OPUS_ATTR_KEY_SPROP_STEREO:
+			attr->spropstereo = (va_arg(ap, int));
+			break;
+		default:
+			ast_log(LOG_WARNING, "unknown attribute type %d\n", key);
+		}
+	}
+}
+
+static struct ast_format_attr_interface opus_interface = {
+	.id = AST_FORMAT_OPUS,
+	.format_attr_get_joint = opus_getjoint,
+	.format_attr_set = opus_set,
+	.format_attr_isset = opus_isset,
+	.format_attr_get_val = opus_get_val,
+	.format_attr_sdp_parse = opus_sdp_parse,
+	.format_attr_sdp_generate = opus_sdp_generate,
+};
+
+static int load_module(void)
+{
+	if (ast_format_attr_reg_interface(&opus_interface)) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	ast_format_attr_unreg_interface(&opus_interface);
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Opus Format Attribute Module",
+	.load = load_module,
+	.unload = unload_module,
+	.load_pri = AST_MODPRI_CHANNEL_DEPEND,
+);