Adds pass-through support for codec CELT.

This patch adds pass-through support for CELT.  CELT
formats are defined in codecs.conf and can be configured
to any sample rate a CELT endpoint supports.  This patch also
addresses a crash in channel.c resulting from a frame list being
freed incorrectly.  This crash was discovered while testing a CELT
translator which had to split encoded audio into multiple frames.
The codec translator is not a part of this patch, but may be
contributed in the future.

Review: https://reviewboard.asterisk.org/r/1294/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@326855 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -9468,6 +9468,7 @@ static int process_sdp_a_audio(const char *a, struct sip_pvt *p, struct ast_rtp_
 
 		if ((format = ast_rtp_codecs_get_payload_format(newaudiortp, codec))) {
 			unsigned int bit_rate;
+			int val = 0;
 
 			switch ((int) format->id) {
 			case AST_FORMAT_SIREN7:
@@ -9500,9 +9501,11 @@ static int process_sdp_a_audio(const char *a, struct sip_pvt *p, struct ast_rtp_
 					}
 				}
 				break;
+			case AST_FORMAT_CELT:
+				if (sscanf(fmtp_string, "framesize=%30u", &val) == 1) {
+					ast_format_append(format, CELT_ATTR_KEY_FRAME_SIZE, val, AST_FORMAT_ATTR_END);
+				}
 			case AST_FORMAT_SILK:
-				{
-					int val = 0;
 				if (sscanf(fmtp_string, "maxaveragebitrate=%30u", &val) == 1) {
 					ast_format_append(format, SILK_ATTR_KEY_MAX_BITRATE, val, AST_FORMAT_ATTR_END);
 				}
@@ -9516,7 +9519,6 @@ static int process_sdp_a_audio(const char *a, struct sip_pvt *p, struct ast_rtp_
 			}
 		}
 	}
-	}
 
 	return found;
 }
@@ -10829,7 +10831,7 @@ static void add_codec_to_sdp(const struct sip_pvt *p,
 {
 	int rtp_code;
 	struct ast_format_list fmt;
-
+	int val = 0;
 
 	if (debug)
 		ast_verbose("Adding codec %d (%s) to SDP\n", format->id, ast_getformatname(format));
@@ -10872,9 +10874,12 @@ static void add_codec_to_sdp(const struct sip_pvt *p,
 		/* Indicate that we only expect 64Kbps */
 		ast_str_append(a_buf, 0, "a=fmtp:%d bitrate=64000\r\n", rtp_code);
 		break;
+	case AST_FORMAT_CELT:
+		if (!ast_format_get_value(format, CELT_ATTR_KEY_FRAME_SIZE, &val) && val > 0) {
+			ast_str_append(a_buf, 0, "a=fmtp:%d framesize=%u\r\n", rtp_code, val);
+		}
+		break;
 	case AST_FORMAT_SILK:
-		{
-			int val = 0;
 		if (!ast_format_get_value(format, SILK_ATTR_KEY_MAX_BITRATE, &val) && val > 5000 && val < 40000) {
 			ast_str_append(a_buf, 0, "a=fmtp:%d maxaveragebitrate=%u\r\n", rtp_code, val);
 		}
@@ -10886,7 +10891,6 @@ static void add_codec_to_sdp(const struct sip_pvt *p,
 		}
 		break;
 	}
-	}
 
 	if (fmt.cur_ms && (fmt.cur_ms < *min_packet_size))
 		*min_packet_size = fmt.cur_ms;

configs/codecs.conf.sample

@@ -126,7 +126,6 @@ maxbitrate=20000
 fec=true
 packetloss_percentage=10;
 
-
 [silk24]
 type=silk
 samprate=24000
@@ -134,3 +133,21 @@ maxbitrate=30000
 fec=true
 packetloss_percentage=10;
 
+
+; Default custom CELT codec definitions. Only one custom CELT definition is allowed
+; per a sample rate.
+;[celt44]
+;type=celt
+;samprate=44100  ; The samplerate in hz. This option is required.
+;framesize=480   ; The framesize option represents the duration of each frame in samples.
+                 ; This must be a factor of 2.  This option is only advertised in an SDP
+                 ; when it is set.  Otherwise a default of framesize of 480 is assumed
+                 ; internally
+
+;[celt48]
+;type=celt
+;samprate=48000
+
+;[celt32]
+;type=celt
+;samprate=32000

include/asterisk/format.h

@@ -28,6 +28,7 @@
 
 #include "asterisk/astobj2.h"
 #include "asterisk/silk.h"
+#include "asterisk/celt.h"
 #define AST_FORMAT_ATTR_SIZE 128
 #define AST_FORMAT_INC 100000
 
@@ -99,6 +100,7 @@ enum ast_format_id {
 	/*! Raw 16-bit Signed Linear (192000 Hz) PCM.  maybe we're taking this too far. */
 	AST_FORMAT_SLINEAR192       = 27 + AST_FORMAT_TYPE_AUDIO,
 	AST_FORMAT_SPEEX32          = 28 + AST_FORMAT_TYPE_AUDIO,
+	AST_FORMAT_CELT             = 29 + AST_FORMAT_TYPE_AUDIO,
 
 	/*! H.261 Video */
 	AST_FORMAT_H261             = 1 + AST_FORMAT_TYPE_VIDEO,

main/channel.c

@@ -1081,6 +1081,8 @@ struct ast_format *ast_best_codec(struct ast_format_cap *cap, struct ast_format
 		AST_FORMAT_SPEEX,
 		/*! SILK is pretty awesome. */
 		AST_FORMAT_SILK,
+		/*! CELT supports crazy high sample rates */
+		AST_FORMAT_CELT,
 		/*! Ick, LPC10 sounds terrible, but at least we have code for it, if you're tacky enough
 		    to use it */
 		AST_FORMAT_LPC10,
@@ -5019,12 +5021,13 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
 		   from the single frame we passed in; if so, feed each one of them to the
 		   channel, freeing each one after it has been written */
 		if ((f != fr) && AST_LIST_NEXT(f, frame_list)) {
-			struct ast_frame *cur, *next;
+			struct ast_frame *cur, *next = NULL;
 			unsigned int skip = 0;
 
-			for (cur = f, next = AST_LIST_NEXT(cur, frame_list);
+			cur = f;
-			     cur;
+			while (cur) {
-			     cur = next, next = cur ? AST_LIST_NEXT(cur, frame_list) : NULL) {
+				next = AST_LIST_NEXT(cur, frame_list);
+				AST_LIST_NEXT(cur, frame_list) = NULL;
 				if (!skip) {
 					if ((res = chan->tech->write(chan, cur)) < 0) {
 						chan->_softhangup |= AST_SOFTHANGUP_DEV;
@@ -5037,6 +5040,7 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
 					}
 				}
 				ast_frfree(cur);
+				cur = next;
 			}
 
 			/* reset f so the code below doesn't attempt to free it */

main/format.c

@@ -748,6 +748,15 @@ int ast_format_rate(const struct ast_format *format)
 		} else {
 			return 8000;
 		}
+	case AST_FORMAT_CELT:
+	{
+		int samplerate;
+		if (!(ast_format_get_value(format,
+			CELT_ATTR_KEY_SAMP_RATE,
+			&samplerate))) {
+			return samplerate;
+		}
+	}
 	default:
 		return 8000;
 	}
@@ -1085,6 +1094,32 @@ init_cleanup:
 	return -1;
 }
 
+static int custom_celt_format(struct ast_format_list *entry, unsigned int maxbitrate, unsigned int framesize)
+{
+	if (!entry->samplespersecond) {
+		ast_log(LOG_WARNING, "Custom CELT format definition '%s' requires sample rate to be defined.\n", entry->name);
+	}
+	ast_format_set(&entry->format, AST_FORMAT_CELT, 0);
+	if (!has_interface(&entry->format)) {
+		return -1;
+	}
+
+	snprintf(entry->desc, sizeof(entry->desc), "CELT Custom Format %dkhz", entry->samplespersecond/1000);
+
+	ast_format_append(&entry->format,
+		CELT_ATTR_KEY_SAMP_RATE, entry->samplespersecond,
+		CELT_ATTR_KEY_MAX_BITRATE, maxbitrate,
+		CELT_ATTR_KEY_FRAME_SIZE, framesize,
+		AST_FORMAT_ATTR_END);
+
+	entry->fr_len = 80;
+	entry->min_ms = 20;
+	entry->max_ms = 20;
+	entry->inc_ms = 20;
+	entry->def_ms = 20;
+	return 0;
+}
+
 static int custom_silk_format(struct ast_format_list *entry, unsigned int maxbitrate, int usedtx, int usefec, int packetloss_percentage)
 {
 	if (!entry->samplespersecond) {
@@ -1144,6 +1179,8 @@ static int conf_process_format_name(const char *name, enum ast_format_id *id)
 {
 	if (!strcasecmp(name, "silk")) {
 		*id = AST_FORMAT_SILK;
+	} else if (!strcasecmp(name, "celt")) {
+		*id = AST_FORMAT_CELT;
 	} else {
 		*id = 0;
 		return -1;
@@ -1163,8 +1200,14 @@ static int conf_process_sample_rate(const char *rate, unsigned int *result)
 		*result = 24000;
 	} else if (!strcasecmp(rate, "32000")) {
 		*result = 32000;
+	} else if (!strcasecmp(rate, "44100")) {
+		*result = 44100;
 	} else if (!strcasecmp(rate, "48000")) {
 		*result = 48000;
+	} else if (!strcasecmp(rate, "96000")) {
+		*result = 96000;
+	} else if (!strcasecmp(rate, "192000")) {
+		*result = 192000;
 	} else {
 		*result = 0;
 		return -1;
@@ -1184,6 +1227,7 @@ static int load_format_config(void)
 	struct {
 		enum ast_format_id id;
 		unsigned int maxbitrate;
+		unsigned int framesize;
 		unsigned int packetloss_percentage;
 		int usefec;
 		int usedtx;
@@ -1221,6 +1265,11 @@ static int load_format_config(void)
 					ast_log(LOG_WARNING, "maxbitrate '%s' at line %d of %s is not supported.\n",
 						var->value, var->lineno, FORMAT_CONFIG);
 				}
+			} else if (!strcasecmp(var->name, "framesize")) {
+				if (sscanf(var->value, "%30u", &settings.framesize) != 1) {
+					ast_log(LOG_WARNING, "framesize '%s' at line %d of %s is not supported.\n",
+						var->value, var->lineno, FORMAT_CONFIG);
+				}
 			} else if (!strcasecmp(var->name, "dtx")) {
 				settings.usedtx = ast_true(var->value) ? 1 : 0;
 			} else if (!strcasecmp(var->name, "fec")) {
@@ -1239,6 +1288,11 @@ static int load_format_config(void)
 				add_it = 1;
 			}
 			break;
+		case AST_FORMAT_CELT:
+			if (!(custom_celt_format(&entry, settings.maxbitrate, settings.framesize))) {
+				add_it = 1;
+			}
+			break;
 		default:
 			ast_log(LOG_WARNING, "Can not create custom format %s\n", entry.name);
 		}

main/frame.c

@@ -1011,6 +1011,10 @@ int ast_codec_get_samples(struct ast_frame *f)
 		} else {
 			return 160;
 		}
+	case AST_FORMAT_CELT:
+		/* TODO The assumes 20ms delivery right now, which is incorrect */
+		samples = ast_format_rate(&f->subclass.format) / 50;
+		break;
 	default:
 		ast_log(LOG_WARNING, "Unable to calculate samples for format %s\n", ast_getformatname(&f->subclass.format));
 	}

main/rtp_engine.c

@@ -1931,6 +1931,10 @@ int ast_rtp_engine_load_format(const struct ast_format *format)
 		set_next_mime_type(format, 0, "audio", "SILK", ast_format_rate(format));
 		add_static_payload(-1, format, 0);
 		break;
+	case AST_FORMAT_CELT:
+		set_next_mime_type(format, 0, "audio", "CELT", ast_format_rate(format));
+		add_static_payload(-1, format, 0);
+		break;
 	default:
 		break;
 	}

res/res_rtp_asterisk.c

@@ -1254,6 +1254,7 @@ static int ast_rtp_write(struct ast_rtp_instance *instance, struct ast_frame *fr
 		case AST_FORMAT_SPEEX16:
 		case AST_FORMAT_SPEEX32:
 		case AST_FORMAT_SILK:
+		case AST_FORMAT_CELT:
 		case AST_FORMAT_G723_1:
 		case AST_FORMAT_SIREN7:
 		case AST_FORMAT_SIREN14: