use track name as key instead of source

Author: stephen-derosa

user_timestamped_video/README.md

@@ -3,10 +3,12 @@
 This example is split into two executables and can demonstrate all four
 producer/consumer combinations:
 
-- `UserTimestampedVideoProducer` publishes a synthetic camera track and stamps
-  each frame with `VideoCaptureOptions::metadata.user_timestamp`.
-- `UserTimestampedVideoConsumer` subscribes to remote camera frames with
-  either the rich or legacy callback path.
+- `UserTimestampedVideoProducer` publishes a synthetic video track named
+  `"timestamped-camera"` and stamps each frame with
+  `VideoCaptureOptions::metadata.user_timestamp`.
+- `UserTimestampedVideoConsumer` subscribes to the remote
+  `"timestamped-camera"` track by name with either the rich or legacy callback
+  path.
 
 Run them in the same room with different participant identities:
 

user_timestamped_video/consumer/main.cpp

@@ -16,7 +16,7 @@
 
 /// UserTimestampedVideoConsumer
 ///
-/// Receives remote camera frames via `Room::setOnVideoFrameEventCallback()` and
+/// Receives remote video frames via `Room::setOnVideoFrameEventCallback()` and
 /// logs any `VideoFrameMetadata::user_timestamp` values that arrive. Pair
 /// with `UserTimestampedVideoProducer` running in another process.
 ///
@@ -44,6 +44,8 @@ using namespace livekit;
 
 namespace {
 
+constexpr const char *kTrackName = "timestamped-camera";
+
 std::atomic<bool> g_running{true};
 
 void handleSignal(int) { g_running.store(false); }
@@ -112,7 +114,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
   void registerExistingParticipants() {
     for (const auto &participant : room_.remoteParticipants()) {
       if (participant) {
-        registerRemoteCameraCallback(participant->identity());
+        registerRemoteVideoCallback(participant->identity());
       }
     }
   }
@@ -125,7 +127,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
 
     std::cout << "[consumer] participant connected: "
               << event.participant->identity() << "\n";
-    registerRemoteCameraCallback(event.participant->identity());
+    registerRemoteVideoCallback(event.participant->identity());
   }
 
   void onParticipantDisconnected(
@@ -135,7 +137,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
     }
 
     const std::string identity = event.participant->identity();
-    room_.clearOnVideoFrameCallback(identity, TrackSource::SOURCE_CAMERA);
+    room_.clearOnVideoFrameCallback(identity, std::string(kTrackName));
 
     {
       std::lock_guard<std::mutex> lock(mutex_);
@@ -146,7 +148,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
   }
 
 private:
-  void registerRemoteCameraCallback(const std::string &identity) {
+  void registerRemoteVideoCallback(const std::string &identity) {
     {
       std::lock_guard<std::mutex> lock(mutex_);
       if (!registered_identities_.insert(identity).second) {
@@ -159,7 +161,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
 
     if (read_user_timestamp_) {
       room_.setOnVideoFrameEventCallback(
-          identity, TrackSource::SOURCE_CAMERA,
+          identity, std::string(kTrackName),
           [identity](const VideoFrameEvent &event) {
             std::cout << "[consumer] from=" << identity
                       << " size=" << event.frame.width() << "x"
@@ -172,7 +174,7 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
           stream_options);
     } else {
       room_.setOnVideoFrameCallback(
-          identity, TrackSource::SOURCE_CAMERA,
+          identity, std::string(kTrackName),
           [identity](const VideoFrame &frame, const std::int64_t timestamp_us) {
             std::cout << "[consumer] from=" << identity
                       << " size=" << frame.width() << "x" << frame.height()
@@ -182,8 +184,8 @@ class UserTimestampedVideoConsumerDelegate : public RoomDelegate {
           stream_options);
     }
 
-    std::cout << "[consumer] listening for camera frames from " << identity
-              << " with user timestamp "
+    std::cout << "[consumer] listening for video frames from " << identity
+              << " track=\"" << kTrackName << "\" with user timestamp "
               << (read_user_timestamp_ ? "enabled" : "ignored") << "\n";
   }
 
@@ -241,7 +243,7 @@ int main(int argc, char *argv[]) {
       for (const auto &participant : room.remoteParticipants()) {
         if (participant) {
           room.clearOnVideoFrameCallback(participant->identity(),
-                                         TrackSource::SOURCE_CAMERA);
+                                         std::string(kTrackName));
         }
       }
     }