fix room logic

Author: stephen-derosa

src/room.cpp

@@ -396,13 +396,19 @@ bool Room::trySetOnAudioFrameCallback(const std::string& participant_identity, c
                                                                    std::move(callback), opts)) {
     return false;
   }
+
+  // If we've already subscribed to the track, handle it immediately
   auto track = findSubscribedRemoteTrack(participant_identity, track_name);
-  if (!track) {
-    LK_LOG_ERROR("Room::trySetOnAudioFrameCallback: track not found for participant={} track_name={}",
-                 participant_identity, track_name);
-    return false;
+  if (track) {
+    subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
+  } else {
+    // The track is not subscribed yet. The callback is registered; the reader
+    // starts when the track is subscribed (see kTrackSubscribed in onEvent).
+    LK_LOG_DEBUG(
+        "Room::trySetOnAudioFrameCallback: track not yet subscribed for participant={} track_name={}; "
+        "callback registered for deferred start",
+        participant_identity, track_name);
   }
-  subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
   return true;
 }
 
@@ -416,13 +422,19 @@ bool Room::trySetOnVideoFrameCallback(const std::string& participant_identity, c
                                                                    std::move(callback), opts)) {
     return false;
   }
+
+  // If we've already subscribed to the track, handle it immediately
   auto track = findSubscribedRemoteTrack(participant_identity, track_name);
-  if (!track) {
-    LK_LOG_ERROR("Room::trySetOnVideoFrameCallback: track not found for participant={} track_name={}",
-                 participant_identity, track_name);
-    return false;
+  if (track) {
+    subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
+  } else {
+    // The track is not subscribed yet. The callback is registered; the reader
+    // starts when the track is subscribed (see kTrackSubscribed in onEvent).
+    LK_LOG_DEBUG(
+        "Room::trySetOnVideoFrameCallback: track not yet subscribed for participant={} track_name={}; "
+        "callback registered for deferred start",
+        participant_identity, track_name);
   }
-  subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
   return true;
 }
 
@@ -436,13 +448,19 @@ bool Room::trySetOnVideoFrameEventCallback(const std::string& participant_identi
                                                                         std::move(callback), opts)) {
     return false;
   }
+
+  // If we've already subscribed to the track, handle it immediately
   auto track = findSubscribedRemoteTrack(participant_identity, track_name);
-  if (!track) {
-    LK_LOG_ERROR("Room::trySetOnVideoFrameEventCallback: track not found for participant={} track_name={}",
-                 participant_identity, track_name);
-    return false;
+  if (track) {
+    subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
+  } else {
+    // The track is not subscribed yet. The callback is registered; the reader
+    // starts when the track is subscribed (see kTrackSubscribed in onEvent).
+    LK_LOG_DEBUG(
+        "Room::trySetOnVideoFrameEventCallback: track not yet subscribed for participant={} track_name={}; "
+        "callback registered for deferred start",
+        participant_identity, track_name);
   }
-  subscription_thread_dispatcher_->handleTrackSubscribed(participant_identity, track_name, track);
   return true;
 }