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/*
* Demo gstreamer app for negotiating and streaming a sendrecv webrtc stream
* with a browser JS app.
*
* gcc webrtc-sendrecv.c $(pkg-config --cflags --libs gstreamer-webrtc-1.0 gstreamer-sdp-1.0 libsoup-2.4 json-glib-1.0) -o webrtc-sendrecv
*
* Author: Nirbheek Chauhan <nirbheek@centricular.com>
*/
#include <gst/gst.h>
#include <gst/sdp/sdp.h>
#define GST_USE_UNSTABLE_API
#include <gst/webrtc/webrtc.h>
/* For signalling */
#include <libsoup/soup.h>
#include <json-glib/json-glib.h>
#include <string.h>
enum AppState {
APP_STATE_UNKNOWN = 0,
APP_STATE_ERROR = 1, /* generic error */
SERVER_CONNECTING = 1000,
SERVER_CONNECTION_ERROR,
SERVER_CONNECTED, /* Ready to register */
SERVER_REGISTERING = 2000,
SERVER_REGISTRATION_ERROR,
SERVER_REGISTERED, /* Ready to call a peer */
SERVER_CLOSED, /* server connection closed by us or the server */
PEER_CONNECTING = 3000,
PEER_CONNECTION_ERROR,
PEER_CONNECTED,
PEER_CALL_NEGOTIATING = 4000,
PEER_CALL_STARTED,
PEER_CALL_STOPPING,
PEER_CALL_STOPPED,
PEER_CALL_ERROR,
};
static GMainLoop *loop;
static GstElement *pipe1, *webrtc1;
static GObject *send_channel, *receive_channel;
static SoupWebsocketConnection *ws_conn = NULL;
static enum AppState app_state = 0;
static const gchar *peer_id = NULL;
static const gchar *server_url = "wss://webrtc.nirbheek.in:8443";
static gboolean disable_ssl = FALSE;
static GOptionEntry entries[] =
{
{ "peer-id", 0, 0, G_OPTION_ARG_STRING, &peer_id, "String ID of the peer to connect to", "ID" },
{ "server", 0, 0, G_OPTION_ARG_STRING, &server_url, "Signalling server to connect to", "URL" },
{ "disable-ssl", 0, 0, G_OPTION_ARG_NONE, &disable_ssl, "Disable ssl", NULL },
{ NULL },
};
static gboolean
cleanup_and_quit_loop (const gchar * msg, enum AppState state)
{
if (msg)
g_printerr ("%s\n", msg);
if (state > 0)
app_state = state;
if (ws_conn) {
if (soup_websocket_connection_get_state (ws_conn) ==
SOUP_WEBSOCKET_STATE_OPEN)
/* This will call us again */
soup_websocket_connection_close (ws_conn, 1000, "");
else
g_object_unref (ws_conn);
}
if (loop) {
g_main_loop_quit (loop);
loop = NULL;
}
/* To allow usage as a GSourceFunc */
return G_SOURCE_REMOVE;
}
static gchar*
get_string_from_json_object (JsonObject * object)
{
JsonNode *root;
JsonGenerator *generator;
gchar *text;
/* Make it the root node */
root = json_node_init_object (json_node_alloc (), object);
generator = json_generator_new ();
json_generator_set_root (generator, root);
text = json_generator_to_data (generator, NULL);
/* Release everything */
g_object_unref (generator);
json_node_free (root);
return text;
}
static void
handle_media_stream (GstPad * pad, GstElement * pipe, const char * convert_name,
const char * sink_name)
{
GstPad *qpad;
GstElement *q, *conv, *resample, *sink;
GstPadLinkReturn ret;
g_print ("Trying to handle stream with %s ! %s", convert_name, sink_name);
q = gst_element_factory_make ("queue", NULL);
g_assert_nonnull (q);
conv = gst_element_factory_make (convert_name, NULL);
g_assert_nonnull (conv);
sink = gst_element_factory_make (sink_name, NULL);
g_assert_nonnull (sink);
if (g_strcmp0 (convert_name, "audioconvert") == 0) {
/* Might also need to resample, so add it just in case.
* Will be a no-op if it's not required. */
resample = gst_element_factory_make ("audioresample", NULL);
g_assert_nonnull (resample);
gst_bin_add_many (GST_BIN (pipe), q, conv, resample, sink, NULL);
gst_element_sync_state_with_parent (q);
gst_element_sync_state_with_parent (conv);
gst_element_sync_state_with_parent (resample);
gst_element_sync_state_with_parent (sink);
gst_element_link_many (q, conv, resample, sink, NULL);
} else {
gst_bin_add_many (GST_BIN (pipe), q, conv, sink, NULL);
gst_element_sync_state_with_parent (q);
gst_element_sync_state_with_parent (conv);
gst_element_sync_state_with_parent (sink);
gst_element_link_many (q, conv, sink, NULL);
}
qpad = gst_element_get_static_pad (q, "sink");
ret = gst_pad_link (pad, qpad);
g_assert_cmphex (ret, ==, GST_PAD_LINK_OK);
}
static void
on_incoming_decodebin_stream (GstElement * decodebin, GstPad * pad,
GstElement * pipe)
{
GstCaps *caps;
const gchar *name;
if (!gst_pad_has_current_caps (pad)) {
g_printerr ("Pad '%s' has no caps, can't do anything, ignoring\n",
GST_PAD_NAME (pad));
return;
}
caps = gst_pad_get_current_caps (pad);
name = gst_structure_get_name (gst_caps_get_structure (caps, 0));
if (g_str_has_prefix (name, "video")) {
handle_media_stream (pad, pipe, "videoconvert", "autovideosink");
} else if (g_str_has_prefix (name, "audio")) {
handle_media_stream (pad, pipe, "audioconvert", "autoaudiosink");
} else {
g_printerr ("Unknown pad %s, ignoring", GST_PAD_NAME (pad));
}
}
static void
on_incoming_stream (GstElement * webrtc, GstPad * pad, GstElement * pipe)
{
GstElement *decodebin;
if (GST_PAD_DIRECTION (pad) != GST_PAD_SRC)
return;
decodebin = gst_element_factory_make ("decodebin", NULL);
g_signal_connect (decodebin, "pad-added",
G_CALLBACK (on_incoming_decodebin_stream), pipe);
gst_bin_add (GST_BIN (pipe), decodebin);
gst_element_sync_state_with_parent (decodebin);
gst_element_link (webrtc, decodebin);
}
static void
send_ice_candidate_message (GstElement * webrtc G_GNUC_UNUSED, guint mlineindex,
gchar * candidate, gpointer user_data G_GNUC_UNUSED)
{
gchar *text;
JsonObject *ice, *msg;
if (app_state < PEER_CALL_NEGOTIATING) {
cleanup_and_quit_loop ("Can't send ICE, not in call", APP_STATE_ERROR);
return;
}
ice = json_object_new ();
json_object_set_string_member (ice, "candidate", candidate);
json_object_set_int_member (ice, "sdpMLineIndex", mlineindex);
msg = json_object_new ();
json_object_set_object_member (msg, "ice", ice);
text = get_string_from_json_object (msg);
json_object_unref (msg);
soup_websocket_connection_send_text (ws_conn, text);
g_free (text);
}
static void
send_sdp_offer (GstWebRTCSessionDescription * offer)
{
gchar *text;
JsonObject *msg, *sdp;
if (app_state < PEER_CALL_NEGOTIATING) {
cleanup_and_quit_loop ("Can't send offer, not in call", APP_STATE_ERROR);
return;
}
text = gst_sdp_message_as_text (offer->sdp);
g_print ("Sending offer:\n%s\n", text);
sdp = json_object_new ();
json_object_set_string_member (sdp, "type", "offer");
json_object_set_string_member (sdp, "sdp", text);
g_free (text);
msg = json_object_new ();
json_object_set_object_member (msg, "sdp", sdp);
text = get_string_from_json_object (msg);
json_object_unref (msg);
soup_websocket_connection_send_text (ws_conn, text);
g_free (text);
}
/* Offer created by our pipeline, to be sent to the peer */
static void
on_offer_created (GstPromise * promise, gpointer user_data)
{
GstWebRTCSessionDescription *offer = NULL;
const GstStructure *reply;
g_assert_cmphex (app_state, ==, PEER_CALL_NEGOTIATING);
g_assert_cmphex (gst_promise_wait(promise), ==, GST_PROMISE_RESULT_REPLIED);
reply = gst_promise_get_reply (promise);
gst_structure_get (reply, "offer",
GST_TYPE_WEBRTC_SESSION_DESCRIPTION, &offer, NULL);
gst_promise_unref (promise);
promise = gst_promise_new ();
g_signal_emit_by_name (webrtc1, "set-local-description", offer, promise);
gst_promise_interrupt (promise);
gst_promise_unref (promise);
/* Send offer to peer */
send_sdp_offer (offer);
gst_webrtc_session_description_free (offer);
}
static void
on_negotiation_needed (GstElement * element, gpointer user_data)
{
GstPromise *promise;
app_state = PEER_CALL_NEGOTIATING;
promise = gst_promise_new_with_change_func (on_offer_created, user_data, NULL);;
g_signal_emit_by_name (webrtc1, "create-offer", NULL, promise);
}
#define STUN_SERVER " stun-server=stun://stun.l.google.com:19302 "
#define RTP_CAPS_OPUS "application/x-rtp,media=audio,encoding-name=OPUS,payload="
#define RTP_CAPS_VP8 "application/x-rtp,media=video,encoding-name=VP8,payload="
static void
data_channel_on_error (GObject * dc, gpointer user_data)
{
cleanup_and_quit_loop ("Data channel error", 0);
}
static void
data_channel_on_open (GObject * dc, gpointer user_data)
{
GBytes *bytes = g_bytes_new ("data", strlen("data"));
g_print ("data channel opened\n");
g_signal_emit_by_name (dc, "send-string", "Hi! from GStreamer");
g_signal_emit_by_name (dc, "send-data", bytes);
g_bytes_unref (bytes);
}
static void
data_channel_on_close (GObject * dc, gpointer user_data)
{
cleanup_and_quit_loop ("Data channel closed", 0);
}
static void
data_channel_on_message_string (GObject * dc, gchar *str, gpointer user_data)
{
g_print ("Received data channel message: %s\n", str);
}
static void
connect_data_channel_signals (GObject * data_channel)
{
g_signal_connect (data_channel, "on-error", G_CALLBACK (data_channel_on_error),
NULL);
g_signal_connect (data_channel, "on-open", G_CALLBACK (data_channel_on_open),
NULL);
g_signal_connect (data_channel, "on-close", G_CALLBACK (data_channel_on_close),
NULL);
g_signal_connect (data_channel, "on-message-string", G_CALLBACK (data_channel_on_message_string),
NULL);
}
static void
on_data_channel (GstElement * webrtc, GObject * data_channel, gpointer user_data)
{
connect_data_channel_signals (data_channel);
receive_channel = data_channel;
}
static gboolean
start_pipeline (void)
{
GstStateChangeReturn ret;
GError *error = NULL;
pipe1 =
gst_parse_launch ("webrtcbin bundle-policy=max-bundle name=sendrecv " STUN_SERVER
"videotestsrc is-live=true pattern=ball ! videoconvert ! queue ! vp8enc deadline=1 ! rtpvp8pay ! "
"queue ! " RTP_CAPS_VP8 "96 ! sendrecv. "
"audiotestsrc is-live=true wave=red-noise ! audioconvert ! audioresample ! queue ! opusenc ! rtpopuspay ! "
"queue ! " RTP_CAPS_OPUS "97 ! sendrecv. ",
&error);
if (error) {
g_printerr ("Failed to parse launch: %s\n", error->message);
g_error_free (error);
goto err;
}
webrtc1 = gst_bin_get_by_name (GST_BIN (pipe1), "sendrecv");
g_assert_nonnull (webrtc1);
/* This is the gstwebrtc entry point where we create the offer and so on. It
* will be called when the pipeline goes to PLAYING. */
g_signal_connect (webrtc1, "on-negotiation-needed",
G_CALLBACK (on_negotiation_needed), NULL);
/* We need to transmit this ICE candidate to the browser via the websockets
* signalling server. Incoming ice candidates from the browser need to be
* added by us too, see on_server_message() */
g_signal_connect (webrtc1, "on-ice-candidate",
G_CALLBACK (send_ice_candidate_message), NULL);
gst_element_set_state (pipe1, GST_STATE_READY);
g_signal_emit_by_name (webrtc1, "create-data-channel", "channel", NULL,
&send_channel);
if (send_channel) {
g_print ("Created data channel\n");
connect_data_channel_signals (send_channel);
} else {
g_print ("Could not create data channel, is usrsctp available?\n");
}
g_signal_connect (webrtc1, "on-data-channel", G_CALLBACK (on_data_channel),
NULL);
/* Incoming streams will be exposed via this signal */
g_signal_connect (webrtc1, "pad-added", G_CALLBACK (on_incoming_stream),
pipe1);
/* Lifetime is the same as the pipeline itself */
gst_object_unref (webrtc1);
g_print ("Starting pipeline\n");
ret = gst_element_set_state (GST_ELEMENT (pipe1), GST_STATE_PLAYING);
if (ret == GST_STATE_CHANGE_FAILURE)
goto err;
return TRUE;
err:
if (pipe1)
g_clear_object (&pipe1);
if (webrtc1)
webrtc1 = NULL;
return FALSE;
}
static gboolean
setup_call (void)
{
gchar *msg;
if (soup_websocket_connection_get_state (ws_conn) !=
SOUP_WEBSOCKET_STATE_OPEN)
return FALSE;
if (!peer_id)
return FALSE;
g_print ("Setting up signalling server call with %s\n", peer_id);
app_state = PEER_CONNECTING;
msg = g_strdup_printf ("SESSION %s", peer_id);
soup_websocket_connection_send_text (ws_conn, msg);
g_free (msg);
return TRUE;
}
static gboolean
register_with_server (void)
{
gchar *hello;
gint32 our_id;
if (soup_websocket_connection_get_state (ws_conn) !=
SOUP_WEBSOCKET_STATE_OPEN)
return FALSE;
our_id = g_random_int_range (10, 10000);
g_print ("Registering id %i with server\n", our_id);
app_state = SERVER_REGISTERING;
/* Register with the server with a random integer id. Reply will be received
* by on_server_message() */
hello = g_strdup_printf ("HELLO %i", our_id);
soup_websocket_connection_send_text (ws_conn, hello);
g_free (hello);
return TRUE;
}
static void
on_server_closed (SoupWebsocketConnection * conn G_GNUC_UNUSED,
gpointer user_data G_GNUC_UNUSED)
{
app_state = SERVER_CLOSED;
cleanup_and_quit_loop ("Server connection closed", 0);
}
/* One mega message handler for our asynchronous calling mechanism */
static void
on_server_message (SoupWebsocketConnection * conn, SoupWebsocketDataType type,
GBytes * message, gpointer user_data)
{
gchar *text;
switch (type) {
case SOUP_WEBSOCKET_DATA_BINARY:
g_printerr ("Received unknown binary message, ignoring\n");
return;
case SOUP_WEBSOCKET_DATA_TEXT: {
gsize size;
const gchar *data = g_bytes_get_data (message, &size);
/* Convert to NULL-terminated string */
text = g_strndup (data, size);
break;
}
default:
g_assert_not_reached ();
}
/* Server has accepted our registration, we are ready to send commands */
if (g_strcmp0 (text, "HELLO") == 0) {
if (app_state != SERVER_REGISTERING) {
cleanup_and_quit_loop ("ERROR: Received HELLO when not registering",
APP_STATE_ERROR);
goto out;
}
app_state = SERVER_REGISTERED;
g_print ("Registered with server\n");
/* Ask signalling server to connect us with a specific peer */
if (!setup_call ()) {
cleanup_and_quit_loop ("ERROR: Failed to setup call", PEER_CALL_ERROR);
goto out;
}
/* Call has been setup by the server, now we can start negotiation */
} else if (g_strcmp0 (text, "SESSION_OK") == 0) {
if (app_state != PEER_CONNECTING) {
cleanup_and_quit_loop ("ERROR: Received SESSION_OK when not calling",
PEER_CONNECTION_ERROR);
goto out;
}
app_state = PEER_CONNECTED;
/* Start negotiation (exchange SDP and ICE candidates) */
if (!start_pipeline ())
cleanup_and_quit_loop ("ERROR: failed to start pipeline",
PEER_CALL_ERROR);
/* Handle errors */
} else if (g_str_has_prefix (text, "ERROR")) {
switch (app_state) {
case SERVER_CONNECTING:
app_state = SERVER_CONNECTION_ERROR;
break;
case SERVER_REGISTERING:
app_state = SERVER_REGISTRATION_ERROR;
break;
case PEER_CONNECTING:
app_state = PEER_CONNECTION_ERROR;
break;
case PEER_CONNECTED:
case PEER_CALL_NEGOTIATING:
app_state = PEER_CALL_ERROR;
default:
app_state = APP_STATE_ERROR;
}
cleanup_and_quit_loop (text, 0);
/* Look for JSON messages containing SDP and ICE candidates */
} else {
JsonNode *root;
JsonObject *object, *child;
JsonParser *parser = json_parser_new ();
if (!json_parser_load_from_data (parser, text, -1, NULL)) {
g_printerr ("Unknown message '%s', ignoring", text);
g_object_unref (parser);
goto out;
}
root = json_parser_get_root (parser);
if (!JSON_NODE_HOLDS_OBJECT (root)) {
g_printerr ("Unknown json message '%s', ignoring", text);
g_object_unref (parser);
goto out;
}
object = json_node_get_object (root);
/* Check type of JSON message */
if (json_object_has_member (object, "sdp")) {
int ret;
GstSDPMessage *sdp;
const gchar *text, *sdptype;
GstWebRTCSessionDescription *answer;
g_assert_cmphex (app_state, ==, PEER_CALL_NEGOTIATING);
child = json_object_get_object_member (object, "sdp");
if (!json_object_has_member (child, "type")) {
cleanup_and_quit_loop ("ERROR: received SDP without 'type'",
PEER_CALL_ERROR);
goto out;
}
sdptype = json_object_get_string_member (child, "type");
/* In this example, we always create the offer and receive one answer.
* See tests/examples/webrtcbidirectional.c in gst-plugins-bad for how to
* handle offers from peers and reply with answers using webrtcbin. */
g_assert_cmpstr (sdptype, ==, "answer");
text = json_object_get_string_member (child, "sdp");
g_print ("Received answer:\n%s\n", text);
ret = gst_sdp_message_new (&sdp);
g_assert_cmphex (ret, ==, GST_SDP_OK);
ret = gst_sdp_message_parse_buffer ((guint8 *) text, strlen (text), sdp);
g_assert_cmphex (ret, ==, GST_SDP_OK);
answer = gst_webrtc_session_description_new (GST_WEBRTC_SDP_TYPE_ANSWER,
sdp);
g_assert_nonnull (answer);
/* Set remote description on our pipeline */
{
GstPromise *promise = gst_promise_new ();
g_signal_emit_by_name (webrtc1, "set-remote-description", answer,
promise);
gst_promise_interrupt (promise);
gst_promise_unref (promise);
}
app_state = PEER_CALL_STARTED;
} else if (json_object_has_member (object, "ice")) {
const gchar *candidate;
gint sdpmlineindex;
child = json_object_get_object_member (object, "ice");
candidate = json_object_get_string_member (child, "candidate");
sdpmlineindex = json_object_get_int_member (child, "sdpMLineIndex");
/* Add ice candidate sent by remote peer */
g_signal_emit_by_name (webrtc1, "add-ice-candidate", sdpmlineindex,
candidate);
} else {
g_printerr ("Ignoring unknown JSON message:\n%s\n", text);
}
g_object_unref (parser);
}
out:
g_free (text);
}
static void
on_server_connected (SoupSession * session, GAsyncResult * res,
SoupMessage *msg)
{
GError *error = NULL;
ws_conn = soup_session_websocket_connect_finish (session, res, &error);
if (error) {
cleanup_and_quit_loop (error->message, SERVER_CONNECTION_ERROR);
g_error_free (error);
return;
}
g_assert_nonnull (ws_conn);
app_state = SERVER_CONNECTED;
g_print ("Connected to signalling server\n");
g_signal_connect (ws_conn, "closed", G_CALLBACK (on_server_closed), NULL);
g_signal_connect (ws_conn, "message", G_CALLBACK (on_server_message), NULL);
/* Register with the server so it knows about us and can accept commands */
register_with_server ();
}
/*
* Connect to the signalling server. This is the entrypoint for everything else.
*/
static void
connect_to_websocket_server_async (void)
{
SoupLogger *logger;
SoupMessage *message;
SoupSession *session;
const char *https_aliases[] = {"wss", NULL};
session = soup_session_new_with_options (SOUP_SESSION_SSL_STRICT, !disable_ssl,
SOUP_SESSION_SSL_USE_SYSTEM_CA_FILE, TRUE,
//SOUP_SESSION_SSL_CA_FILE, "/etc/ssl/certs/ca-bundle.crt",
SOUP_SESSION_HTTPS_ALIASES, https_aliases, NULL);
logger = soup_logger_new (SOUP_LOGGER_LOG_BODY, -1);
soup_session_add_feature (session, SOUP_SESSION_FEATURE (logger));
g_object_unref (logger);
message = soup_message_new (SOUP_METHOD_GET, server_url);
g_print ("Connecting to server...\n");
/* Once connected, we will register */
soup_session_websocket_connect_async (session, message, NULL, NULL, NULL,
(GAsyncReadyCallback) on_server_connected, message);
app_state = SERVER_CONNECTING;
}
static gboolean
check_plugins (void)
{
int i;
gboolean ret;
GstPlugin *plugin;
GstRegistry *registry;
const gchar *needed[] = { "opus", "vpx", "nice", "webrtc", "dtls", "srtp",
"rtpmanager", "videotestsrc", "audiotestsrc", NULL};
registry = gst_registry_get ();
ret = TRUE;
for (i = 0; i < g_strv_length ((gchar **) needed); i++) {
plugin = gst_registry_find_plugin (registry, needed[i]);
if (!plugin) {
g_print ("Required gstreamer plugin '%s' not found\n", needed[i]);
ret = FALSE;
continue;
}
gst_object_unref (plugin);
}
return ret;
}
int
main (int argc, char *argv[])
{
GOptionContext *context;
GError *error = NULL;
context = g_option_context_new ("- gstreamer webrtc sendrecv demo");
g_option_context_add_main_entries (context, entries, NULL);
g_option_context_add_group (context, gst_init_get_option_group ());
if (!g_option_context_parse (context, &argc, &argv, &error)) {
g_printerr ("Error initializing: %s\n", error->message);
return -1;
}
if (!check_plugins ())
return -1;
if (!peer_id) {
g_printerr ("--peer-id is a required argument\n");
return -1;
}
/* Disable ssl when running a localhost server, because
* it's probably a test server with a self-signed certificate */
{
GstUri *uri = gst_uri_from_string (server_url);
if (g_strcmp0 ("localhost", gst_uri_get_host (uri)) == 0 ||
g_strcmp0 ("127.0.0.1", gst_uri_get_host (uri)) == 0)
disable_ssl = TRUE;
gst_uri_unref (uri);
}
loop = g_main_loop_new (NULL, FALSE);
connect_to_websocket_server_async ();
g_main_loop_run (loop);
g_main_loop_unref (loop);
if (pipe1) {
gst_element_set_state (GST_ELEMENT (pipe1), GST_STATE_NULL);
g_print ("Pipeline stopped\n");
gst_object_unref (pipe1);
}
return 0;
}