matrixion/src/WebRTCSession.cpp
2020-07-25 18:11:11 -04:00

479 lines
15 KiB
C++

#include <cctype>
#include "WebRTCSession.h"
#include "Logging.h"
extern "C" {
#include "gst/gst.h"
#include "gst/sdp/sdp.h"
#define GST_USE_UNSTABLE_API
#include "gst/webrtc/webrtc.h"
}
Q_DECLARE_METATYPE(WebRTCSession::State)
namespace {
bool gisoffer;
std::string glocalsdp;
std::vector<mtx::events::msg::CallCandidates::Candidate> gcandidates;
gboolean newBusMessage(GstBus *bus G_GNUC_UNUSED, GstMessage *msg, gpointer user_data);
GstWebRTCSessionDescription* parseSDP(const std::string &sdp, GstWebRTCSDPType type);
void generateOffer(GstElement *webrtc);
void setLocalDescription(GstPromise *promise, gpointer webrtc);
void addLocalICECandidate(GstElement *webrtc G_GNUC_UNUSED, guint mlineIndex, gchar *candidate, gpointer G_GNUC_UNUSED);
gboolean onICEGatheringCompletion(gpointer timerid);
void createAnswer(GstPromise *promise, gpointer webrtc);
void addDecodeBin(GstElement *webrtc G_GNUC_UNUSED, GstPad *newpad, GstElement *pipe);
void linkNewPad(GstElement *decodebin G_GNUC_UNUSED, GstPad *newpad, GstElement *pipe);
std::string::const_iterator findName(const std::string &sdp, const std::string &name);
int getPayloadType(const std::string &sdp, const std::string &name);
}
WebRTCSession::WebRTCSession() : QObject()
{
qRegisterMetaType<WebRTCSession::State>();
connect(this, &WebRTCSession::stateChanged, this, &WebRTCSession::setState);
}
bool
WebRTCSession::init(std::string *errorMessage)
{
if (initialised_)
return true;
GError *error = nullptr;
if (!gst_init_check(nullptr, nullptr, &error)) {
std::string strError = std::string("WebRTC: failed to initialise GStreamer: ");
if (error) {
strError += error->message;
g_error_free(error);
}
nhlog::ui()->error(strError);
if (errorMessage)
*errorMessage = strError;
return false;
}
gchar *version = gst_version_string();
std::string gstVersion(version);
g_free(version);
nhlog::ui()->info("WebRTC: initialised " + gstVersion);
// GStreamer Plugins:
// Base: audioconvert, audioresample, opus, playback, volume
// Good: autodetect, rtpmanager, vpx
// Bad: dtls, srtp, webrtc
// libnice [GLib]: nice
initialised_ = true;
std::string strError = gstVersion + ": Missing plugins: ";
const gchar *needed[] = {"audioconvert", "audioresample", "autodetect", "dtls", "nice",
"opus", "playback", "rtpmanager", "srtp", "vpx", "volume", "webrtc", nullptr};
GstRegistry *registry = gst_registry_get();
for (guint i = 0; i < g_strv_length((gchar**)needed); i++) {
GstPlugin *plugin = gst_registry_find_plugin(registry, needed[i]);
if (!plugin) {
strError += needed[i];
initialised_ = false;
continue;
}
gst_object_unref(plugin);
}
if (!initialised_) {
nhlog::ui()->error(strError);
if (errorMessage)
*errorMessage = strError;
}
return initialised_;
}
bool
WebRTCSession::createOffer()
{
gisoffer = true;
glocalsdp.clear();
gcandidates.clear();
return startPipeline(111); // a dynamic opus payload type
}
bool
WebRTCSession::acceptOffer(const std::string &sdp)
{
nhlog::ui()->debug("WebRTC: received offer:\n{}", sdp);
if (state_ != State::DISCONNECTED)
return false;
gisoffer = false;
glocalsdp.clear();
gcandidates.clear();
int opusPayloadType = getPayloadType(sdp, "opus");
if (opusPayloadType == -1)
return false;
GstWebRTCSessionDescription *offer = parseSDP(sdp, GST_WEBRTC_SDP_TYPE_OFFER);
if (!offer)
return false;
if (!startPipeline(opusPayloadType)) {
gst_webrtc_session_description_free(offer);
return false;
}
// set-remote-description first, then create-answer
GstPromise *promise = gst_promise_new_with_change_func(createAnswer, webrtc_, nullptr);
g_signal_emit_by_name(webrtc_, "set-remote-description", offer, promise);
gst_webrtc_session_description_free(offer);
return true;
}
bool
WebRTCSession::startPipeline(int opusPayloadType)
{
if (state_ != State::DISCONNECTED)
return false;
emit stateChanged(State::INITIATING);
if (!createPipeline(opusPayloadType))
return false;
webrtc_ = gst_bin_get_by_name(GST_BIN(pipe_), "webrtcbin");
if (!stunServer_.empty()) {
nhlog::ui()->info("WebRTC: setting STUN server: {}", stunServer_);
g_object_set(webrtc_, "stun-server", stunServer_.c_str(), nullptr);
}
for (const auto &uri : turnServers_) {
nhlog::ui()->info("WebRTC: setting TURN server: {}", uri);
gboolean udata;
g_signal_emit_by_name(webrtc_, "add-turn-server", uri.c_str(), (gpointer)(&udata));
}
// generate the offer when the pipeline goes to PLAYING
if (gisoffer)
g_signal_connect(webrtc_, "on-negotiation-needed", G_CALLBACK(generateOffer), nullptr);
// on-ice-candidate is emitted when a local ICE candidate has been gathered
g_signal_connect(webrtc_, "on-ice-candidate", G_CALLBACK(addLocalICECandidate), nullptr);
// incoming streams trigger pad-added
gst_element_set_state(pipe_, GST_STATE_READY);
g_signal_connect(webrtc_, "pad-added", G_CALLBACK(addDecodeBin), pipe_);
// webrtcbin lifetime is the same as that of the pipeline
gst_object_unref(webrtc_);
// start the pipeline
GstStateChangeReturn ret = gst_element_set_state(pipe_, GST_STATE_PLAYING);
if (ret == GST_STATE_CHANGE_FAILURE) {
nhlog::ui()->error("WebRTC: unable to start pipeline");
end();
return false;
}
GstBus *bus = gst_pipeline_get_bus(GST_PIPELINE(pipe_));
gst_bus_add_watch(bus, newBusMessage, this);
gst_object_unref(bus);
emit stateChanged(State::INITIATED);
return true;
}
#define RTP_CAPS_OPUS "application/x-rtp,media=audio,encoding-name=OPUS,payload="
bool
WebRTCSession::createPipeline(int opusPayloadType)
{
std::string pipeline("webrtcbin bundle-policy=max-bundle name=webrtcbin "
"autoaudiosrc ! volume name=srclevel ! audioconvert ! audioresample ! queue ! opusenc ! rtpopuspay ! "
"queue ! " RTP_CAPS_OPUS + std::to_string(opusPayloadType) + " ! webrtcbin.");
webrtc_ = nullptr;
GError *error = nullptr;
pipe_ = gst_parse_launch(pipeline.c_str(), &error);
if (error) {
nhlog::ui()->error("WebRTC: failed to parse pipeline: {}", error->message);
g_error_free(error);
end();
return false;
}
return true;
}
bool
WebRTCSession::acceptAnswer(const std::string &sdp)
{
nhlog::ui()->debug("WebRTC: received answer:\n{}", sdp);
if (state_ != State::OFFERSENT)
return false;
GstWebRTCSessionDescription *answer = parseSDP(sdp, GST_WEBRTC_SDP_TYPE_ANSWER);
if (!answer) {
end();
return false;
}
g_signal_emit_by_name(webrtc_, "set-remote-description", answer, nullptr);
gst_webrtc_session_description_free(answer);
return true;
}
void
WebRTCSession::acceptICECandidates(const std::vector<mtx::events::msg::CallCandidates::Candidate> &candidates)
{
if (state_ >= State::INITIATED) {
for (const auto &c : candidates) {
nhlog::ui()->debug("WebRTC: remote candidate: (m-line:{}):{}", c.sdpMLineIndex, c.candidate);
g_signal_emit_by_name(webrtc_, "add-ice-candidate", c.sdpMLineIndex, c.candidate.c_str());
}
if (state_ == State::OFFERSENT)
emit stateChanged(State::CONNECTING);
}
}
bool
WebRTCSession::toggleMuteAudioSrc(bool &isMuted)
{
if (state_ < State::INITIATED)
return false;
GstElement *srclevel = gst_bin_get_by_name(GST_BIN(pipe_), "srclevel");
if (!srclevel)
return false;
gboolean muted;
g_object_get(srclevel, "mute", &muted, nullptr);
g_object_set(srclevel, "mute", !muted, nullptr);
gst_object_unref(srclevel);
isMuted = !muted;
return true;
}
void
WebRTCSession::end()
{
nhlog::ui()->debug("WebRTC: ending session");
if (pipe_) {
gst_element_set_state(pipe_, GST_STATE_NULL);
gst_object_unref(pipe_);
pipe_ = nullptr;
}
webrtc_ = nullptr;
if (state_ != State::DISCONNECTED)
emit stateChanged(State::DISCONNECTED);
}
namespace {
std::string::const_iterator findName(const std::string &sdp, const std::string &name)
{
return std::search(sdp.cbegin(), sdp.cend(), name.cbegin(), name.cend(),
[](unsigned char c1, unsigned char c2) {return std::tolower(c1) == std::tolower(c2);});
}
int getPayloadType(const std::string &sdp, const std::string &name)
{
// eg a=rtpmap:111 opus/48000/2
auto e = findName(sdp, name);
if (e == sdp.cend()) {
nhlog::ui()->error("WebRTC: remote offer - " + name + " attribute missing");
return -1;
}
if (auto s = sdp.rfind(':', e - sdp.cbegin()); s == std::string::npos) {
nhlog::ui()->error("WebRTC: remote offer - unable to determine " + name + " payload type");
return -1;
}
else {
++s;
try {
return std::stoi(std::string(sdp, s, e - sdp.cbegin() - s));
}
catch(...) {
nhlog::ui()->error("WebRTC: remote offer - unable to determine " + name + " payload type");
}
}
return -1;
}
gboolean
newBusMessage(GstBus *bus G_GNUC_UNUSED, GstMessage *msg, gpointer user_data)
{
WebRTCSession *session = (WebRTCSession*)user_data;
switch (GST_MESSAGE_TYPE(msg)) {
case GST_MESSAGE_EOS:
nhlog::ui()->error("WebRTC: end of stream");
session->end();
break;
case GST_MESSAGE_ERROR:
GError *error;
gchar *debug;
gst_message_parse_error(msg, &error, &debug);
nhlog::ui()->error("WebRTC: error from element {}: {}", GST_OBJECT_NAME(msg->src), error->message);
g_clear_error(&error);
g_free(debug);
session->end();
break;
default:
break;
}
return TRUE;
}
GstWebRTCSessionDescription*
parseSDP(const std::string &sdp, GstWebRTCSDPType type)
{
GstSDPMessage *msg;
gst_sdp_message_new(&msg);
if (gst_sdp_message_parse_buffer((guint8*)sdp.c_str(), sdp.size(), msg) == GST_SDP_OK) {
return gst_webrtc_session_description_new(type, msg);
}
else {
nhlog::ui()->error("WebRTC: failed to parse remote session description");
gst_object_unref(msg);
return nullptr;
}
}
void
generateOffer(GstElement *webrtc)
{
// create-offer first, then set-local-description
GstPromise *promise = gst_promise_new_with_change_func(setLocalDescription, webrtc, nullptr);
g_signal_emit_by_name(webrtc, "create-offer", nullptr, promise);
}
void
setLocalDescription(GstPromise *promise, gpointer webrtc)
{
const GstStructure *reply = gst_promise_get_reply(promise);
gboolean isAnswer = gst_structure_id_has_field(reply, g_quark_from_string("answer"));
GstWebRTCSessionDescription *gstsdp = nullptr;
gst_structure_get(reply, isAnswer ? "answer" : "offer", GST_TYPE_WEBRTC_SESSION_DESCRIPTION, &gstsdp, nullptr);
gst_promise_unref(promise);
g_signal_emit_by_name(webrtc, "set-local-description", gstsdp, nullptr);
gchar *sdp = gst_sdp_message_as_text(gstsdp->sdp);
glocalsdp = std::string(sdp);
g_free(sdp);
gst_webrtc_session_description_free(gstsdp);
nhlog::ui()->debug("WebRTC: local description set ({}):\n{}", isAnswer ? "answer" : "offer", glocalsdp);
}
void
addLocalICECandidate(GstElement *webrtc G_GNUC_UNUSED, guint mlineIndex, gchar *candidate, gpointer G_GNUC_UNUSED)
{
nhlog::ui()->debug("WebRTC: local candidate: (m-line:{}):{}", mlineIndex, candidate);
if (WebRTCSession::instance().state() == WebRTCSession::State::CONNECTED) {
emit WebRTCSession::instance().newICECandidate({"audio", (uint16_t)mlineIndex, candidate});
return;
}
gcandidates.push_back({"audio", (uint16_t)mlineIndex, candidate});
// GStreamer v1.16: webrtcbin's notify::ice-gathering-state triggers GST_WEBRTC_ICE_GATHERING_STATE_COMPLETE too early
// fixed in v1.18
// use a 100ms timeout in the meantime
static guint timerid = 0;
if (timerid)
g_source_remove(timerid);
timerid = g_timeout_add(100, onICEGatheringCompletion, &timerid);
}
gboolean
onICEGatheringCompletion(gpointer timerid)
{
*(guint*)(timerid) = 0;
if (gisoffer) {
emit WebRTCSession::instance().offerCreated(glocalsdp, gcandidates);
emit WebRTCSession::instance().stateChanged(WebRTCSession::State::OFFERSENT);
}
else {
emit WebRTCSession::instance().answerCreated(glocalsdp, gcandidates);
emit WebRTCSession::instance().stateChanged(WebRTCSession::State::CONNECTING);
}
return FALSE;
}
void
createAnswer(GstPromise *promise, gpointer webrtc)
{
// create-answer first, then set-local-description
gst_promise_unref(promise);
promise = gst_promise_new_with_change_func(setLocalDescription, webrtc, nullptr);
g_signal_emit_by_name(webrtc, "create-answer", nullptr, promise);
}
void
addDecodeBin(GstElement *webrtc G_GNUC_UNUSED, GstPad *newpad, GstElement *pipe)
{
if (GST_PAD_DIRECTION(newpad) != GST_PAD_SRC)
return;
nhlog::ui()->debug("WebRTC: received incoming stream");
GstElement *decodebin = gst_element_factory_make("decodebin", nullptr);
g_signal_connect(decodebin, "pad-added", G_CALLBACK(linkNewPad), pipe);
gst_bin_add(GST_BIN(pipe), decodebin);
gst_element_sync_state_with_parent(decodebin);
GstPad *sinkpad = gst_element_get_static_pad(decodebin, "sink");
if (GST_PAD_LINK_FAILED(gst_pad_link(newpad, sinkpad)))
nhlog::ui()->error("WebRTC: unable to link new pad");
gst_object_unref(sinkpad);
}
void
linkNewPad(GstElement *decodebin G_GNUC_UNUSED, GstPad *newpad, GstElement *pipe)
{
GstCaps *caps = gst_pad_get_current_caps(newpad);
if (!caps)
return;
const gchar *name = gst_structure_get_name(gst_caps_get_structure(caps, 0));
gst_caps_unref(caps);
GstPad *queuepad = nullptr;
GstElement *queue = gst_element_factory_make("queue", nullptr);
if (g_str_has_prefix(name, "audio")) {
nhlog::ui()->debug("WebRTC: received incoming audio stream");
GstElement *convert = gst_element_factory_make("audioconvert", nullptr);
GstElement *resample = gst_element_factory_make("audioresample", nullptr);
GstElement *sink = gst_element_factory_make("autoaudiosink", nullptr);
gst_bin_add_many(GST_BIN(pipe), queue, convert, resample, sink, nullptr);
gst_element_sync_state_with_parent(queue);
gst_element_sync_state_with_parent(convert);
gst_element_sync_state_with_parent(resample);
gst_element_sync_state_with_parent(sink);
gst_element_link_many(queue, convert, resample, sink, nullptr);
queuepad = gst_element_get_static_pad(queue, "sink");
}
else if (g_str_has_prefix(name, "video")) {
nhlog::ui()->debug("WebRTC: received incoming video stream");
GstElement *convert = gst_element_factory_make("videoconvert", nullptr);
GstElement *sink = gst_element_factory_make("autovideosink", nullptr);
gst_bin_add_many(GST_BIN(pipe), queue, convert, sink, nullptr);
gst_element_sync_state_with_parent(queue);
gst_element_sync_state_with_parent(convert);
gst_element_sync_state_with_parent(sink);
gst_element_link_many(queue, convert, sink, nullptr);
queuepad = gst_element_get_static_pad(queue, "sink");
}
if (queuepad) {
if (GST_PAD_LINK_FAILED(gst_pad_link(newpad, queuepad)))
nhlog::ui()->error("WebRTC: unable to link new pad");
else {
emit WebRTCSession::instance().stateChanged(WebRTCSession::State::CONNECTED);
}
gst_object_unref(queuepad);
}
}
}