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bridge: Change participant SFU streams when source streams change.

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Some endpoints do not like a stream being reused for a new
media stream. The frame/jitterbuffer can rely on underlying
attributes of the media stream in order to order the packets.
When a new stream takes its place without any notice the
buffer can get confused and the media ends up getting dropped.

This change uses the SSRC change to determine that a new source
is reusing an existing stream and then bridge_softmix renegotiates
each participant such that they see a new media stream. This
causes the frame/jitterbuffer to start fresh and work as expected.

ASTERISK-27277

Change-Id: I30ccbdba16ca073d7f31e0e59ab778c153afae07
This commit is contained in:
Joshua Colp
2017-09-16 11:19:59 -03:00
parent 5ff46578aa
commit f2985e3106
9 changed files with 162 additions and 9 deletions
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135
bridges/bridge_softmix.c
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@@ -79,7 +79,7 @@ struct softmix_stats {
struct softmix_translate_helper_entry {
int num_times_requested; /*!< Once this entry is no longer requested, free the trans_pvt
and re-init if it was usable. */
and re-init if it was usable. */
struct ast_format *dst_format; /*!< The destination format for this helper */
struct ast_trans_pvt *trans_pvt; /*!< the translator for this slot. */
struct ast_frame *out_frame; /*!< The output frame from the last translation */
@@ -493,21 +493,21 @@ static int append_source_streams(struct ast_stream_topology *dest,
for (i = 0; i < ast_stream_topology_get_count(source); ++i) {
struct ast_stream *stream;
struct ast_stream *stream_clone;
char *stream_clone_name;
size_t stream_clone_name_len;
char *stream_clone_name = NULL;
stream = ast_stream_topology_get_stream(source, i);
if (!is_video_source(stream)) {
continue;
}
/* The +3 is for the two underscore separators and null terminator */
stream_clone_name_len = SOFTBRIDGE_VIDEO_DEST_LEN + strlen(channel_name) + strlen(ast_stream_get_name(stream)) + 3;
stream_clone_name = ast_alloca(stream_clone_name_len);
snprintf(stream_clone_name, stream_clone_name_len, "%s_%s_%s", SOFTBRIDGE_VIDEO_DEST_PREFIX,
channel_name, ast_stream_get_name(stream));
if (ast_asprintf(&stream_clone_name, "%s_%s_%s", SOFTBRIDGE_VIDEO_DEST_PREFIX,
channel_name, ast_stream_get_name(stream)) < 0) {
ast_free(stream_clone_name);
return -1;
}
stream_clone = ast_stream_clone(stream, stream_clone_name);
ast_free(stream_clone_name);
if (!stream_clone) {
return -1;
}
@@ -987,6 +987,120 @@ static void softmix_bridge_write_voice(struct ast_bridge *bridge, struct ast_bri
}
}
static int remove_all_original_streams(struct ast_stream_topology *dest,
const struct ast_stream_topology *source,
const struct ast_stream_topology *original)
{
int i;
for (i = 0; i < ast_stream_topology_get_count(source); ++i) {
struct ast_stream *stream;
int original_index;
stream = ast_stream_topology_get_stream(source, i);
/* Mark the existing stream as removed so we get a new one, this will get
* reused on a subsequent renegotiation.
*/
for (original_index = 0; original_index < ast_stream_topology_get_count(original); ++original_index) {
struct ast_stream *original_stream = ast_stream_topology_get_stream(original, original_index);
if (!strcmp(ast_stream_get_name(stream), ast_stream_get_name(original_stream))) {
struct ast_stream *removed;
/* Since the participant is still going to be in the bridge we
* change the name so that routing does not attempt to route video
* to this stream.
*/
removed = ast_stream_clone(stream, "removed");
if (!removed) {
return -1;
}
ast_stream_set_state(removed, AST_STREAM_STATE_REMOVED);
/* The destination topology can only ever contain the same, or more,
* streams than the original so this is safe.
*/
if (ast_stream_topology_set_stream(dest, original_index, removed)) {
ast_stream_free(removed);
return -1;
}
break;
}
}
}
return 0;
}
static void sfu_topologies_on_source_change(struct ast_bridge_channel *source, struct ast_bridge_channels_list *participants)
{
struct ast_stream_topology *source_video = NULL;
struct ast_bridge_channel *participant;
int res;
source_video = ast_stream_topology_alloc();
if (!source_video) {
return;
}
ast_channel_lock(source->chan);
res = append_source_streams(source_video, ast_channel_name(source->chan), ast_channel_get_stream_topology(source->chan));
ast_channel_unlock(source->chan);
if (res) {
goto cleanup;
}
AST_LIST_TRAVERSE(participants, participant, entry) {
struct ast_stream_topology *original_topology;
struct ast_stream_topology *participant_topology;
if (participant == source) {
continue;
}
ast_channel_lock(participant->chan);
original_topology = ast_stream_topology_clone(ast_channel_get_stream_topology(participant->chan));
ast_channel_unlock(participant->chan);
if (!original_topology) {
goto cleanup;
}
participant_topology = ast_stream_topology_clone(original_topology);
if (!participant_topology) {
ast_stream_topology_free(original_topology);
goto cleanup;
}
/* We add all the source streams back in, if any removed streams are already present they will
* get used first followed by appending new ones.
*/
if (append_all_streams(participant_topology, source_video)) {
ast_stream_topology_free(participant_topology);
ast_stream_topology_free(original_topology);
goto cleanup;
}
/* And the original existing streams get marked as removed. This causes the remote side to see
* a new stream for the source streams.
*/
if (remove_all_original_streams(participant_topology, source_video, original_topology)) {
ast_stream_topology_free(participant_topology);
ast_stream_topology_free(original_topology);
goto cleanup;
}
ast_channel_request_stream_topology_change(participant->chan, participant_topology, NULL);
ast_stream_topology_free(participant_topology);
ast_stream_topology_free(original_topology);
}
cleanup:
ast_stream_topology_free(source_video);
}
/*!
* \internal
* \brief Determine what to do with a control frame.
@@ -1016,6 +1130,11 @@ static int softmix_bridge_write_control(struct ast_bridge *bridge, struct ast_br
softmix_data->last_video_update = ast_tvnow();
}
break;
case AST_CONTROL_STREAM_TOPOLOGY_SOURCE_CHANGED:
if (bridge->softmix.video_mode.mode == AST_BRIDGE_VIDEO_MODE_SFU) {
sfu_topologies_on_source_change(bridge_channel, &bridge->channels);
}
break;
default:
break;
}