app_confbridge / bridge_softmix: Add ability to configure REMB interval.

This change adds a configuration option to app_confbridge which can be
used to set the interval at which we will send a combined REMB (remote
estimated maximum bitrate) frame to sources of video. The bridging API
has also been extended slightly to allow setting this so bridge_softmix
can use it.

ASTERISK-27786

Change-Id: I0e49eae60f369c86434414f3cb8278709c793c82

apps/app_confbridge.c

@@ -1543,6 +1543,7 @@ static struct confbridge_conference *join_conference_bridge(const char *conferen
 		} else if (ast_test_flag(&conference->b_profile, BRIDGE_OPT_VIDEO_SRC_SFU)) {
 			ast_bridge_set_sfu_video_mode(conference->bridge);
 			ast_bridge_set_video_update_discard(conference->bridge, conference->b_profile.video_update_discard);
+			ast_bridge_set_remb_send_interval(conference->bridge, conference->b_profile.remb_send_interval);
 		}
 
 		/* Link it into the conference bridges container */

apps/confbridge/conf_config_parser.c

@@ -458,6 +458,18 @@
 						video update requests from clients.
 					</para></description>
 				</configOption>
+				<configOption name="remb_send_interval" default="0">
+					<synopsis>Sets the interval in milliseconds that a combined REMB frame will be sent to video sources</synopsis>
+					<description><para>
+						Sets the interval in milliseconds that a combined REMB frame will be sent
+						to video sources. This is done by taking all REMB frames that have been
+						received since the last REMB frame was sent, making a combined value,
+						and sending it to the source. A REMB frame contains receiver estimated
+						maximum bitrate information. By creating a combined REMB frame the
+						sender of video can be influenced on the bitrate they choose, allowing
+						better quality for all receivers.
+					</para></description>
+				</configOption>
 				<configOption name="template">
 					<synopsis>When using the CONFBRIDGE dialplan function, use a bridge profile as a template for creating a new temporary profile</synopsis>
 				</configOption>
@@ -1661,6 +1673,7 @@ static char *handle_cli_confbridge_show_bridge_profile(struct ast_cli_entry *e,
 	}
 
 	ast_cli(a->fd,"Video Update Discard: %u\n", b_profile.video_update_discard);
+	ast_cli(a->fd,"REMB Send Interval: %u\n", b_profile.remb_send_interval);
 
 	ast_cli(a->fd,"sound_only_person:    %s\n", conf_get_sound(CONF_SOUND_ONLY_PERSON, b_profile.sounds));
 	ast_cli(a->fd,"sound_only_one:       %s\n", conf_get_sound(CONF_SOUND_ONLY_ONE, b_profile.sounds));
@@ -2231,6 +2244,7 @@ int conf_load_config(void)
 	aco_option_register(&cfg_info, "language", ACO_EXACT, bridge_types, "en", OPT_CHAR_ARRAY_T, 0, CHARFLDSET(struct bridge_profile, language));
 	aco_option_register_custom(&cfg_info, "sound_", ACO_PREFIX, bridge_types, NULL, sound_option_handler, 0);
 	aco_option_register(&cfg_info, "video_update_discard", ACO_EXACT, bridge_types, "2000", OPT_UINT_T, 0, FLDSET(struct bridge_profile, video_update_discard));
+	aco_option_register(&cfg_info, "remb_send_interval", ACO_EXACT, bridge_types, "0", OPT_UINT_T, 0, FLDSET(struct bridge_profile, remb_send_interval));
 	/* This option should only be used with the CONFBRIDGE dialplan function */
 	aco_option_register_custom(&cfg_info, "template", ACO_EXACT, bridge_types, NULL, bridge_template_handler, 0);
 

apps/confbridge/include/confbridge.h

@@ -222,6 +222,7 @@ struct bridge_profile {
 	struct bridge_profile_sounds *sounds;
 	char regcontext[AST_MAX_CONTEXT];
 	unsigned int video_update_discard; /*!< Amount of time after sending a video update request that subsequent requests should be discarded */
+	unsigned int remb_send_interval; /*!< Interval at which a combined REMB frame is sent to video sources */
 };
 
 /*! \brief The structure that represents a conference bridge */

configs/samples/confbridge.conf.sample

@@ -235,6 +235,10 @@ type=bridge
                            ; the video stream. Since a full frame can be large limiting how often they occur can
                            ; reduce bandwidth usage at the cost of increasing how long it may take a newly joined
                            ; channel to receive the video stream.
+;remb_send_interval=1000   ; Interval (in milliseconds) at which a combined REMB frame will be sent to sources of video.
+                           ; A REMB frame contains receiver estimated maximum bitrate information. By creating a combined
+                           ; frame and sending it to the sources of video the sender can be influenced on what bitrate
+                           ; they choose allowing a better experience for the receivers. This defaults to 0, or disabled.
 
 ; All sounds in the conference are customizable using the bridge profile options below.
 ; Simply state the option followed by the filename or full path of the filename after

include/asterisk/bridge.h

@@ -135,6 +135,7 @@ struct ast_bridge_video_mode {
 		struct ast_bridge_video_talker_src_data talker_src_data;
 	} mode_data;
 	unsigned int video_update_discard;
+	unsigned int remb_send_interval;
 };
 
 /*!
@@ -911,6 +912,14 @@ void ast_bridge_set_sfu_video_mode(struct ast_bridge *bridge);
  */
 void ast_bridge_set_video_update_discard(struct ast_bridge *bridge, unsigned int video_update_discard);
 
+/*!
+ * \brief Set the interval at which a combined REMB frame will be sent to video sources
+ *
+ * \param bridge Bridge to set the REMB send interval on
+ * \param remb_send_interval The REMB send interval
+ */
+void ast_bridge_set_remb_send_interval(struct ast_bridge *bridge, unsigned int remb_send_interval);
+
 /*!
  * \brief Update information about talker energy for talker src video mode.
  */

main/bridge.c

@@ -3850,6 +3850,13 @@ void ast_bridge_set_video_update_discard(struct ast_bridge *bridge, unsigned int
 	ast_bridge_unlock(bridge);
 }
 
+void ast_bridge_set_remb_send_interval(struct ast_bridge *bridge, unsigned int remb_send_interval)
+{
+	ast_bridge_lock(bridge);
+	bridge->softmix.video_mode.remb_send_interval = remb_send_interval;
+	ast_bridge_unlock(bridge);
+}
+
 void ast_bridge_update_talker_src_video_mode(struct ast_bridge *bridge, struct ast_channel *chan, int talker_energy, int is_keyframe)
 {
 	struct ast_bridge_video_talker_src_data *data;