From c473ddd4ea084746835e228f8e4b87ceb64f32d5 Mon Sep 17 00:00:00 2001
From: Jacob Gelman <3182119+ladvoc@users.noreply.github.com>
Date: Thu, 6 Nov 2025 15:43:50 +1100
Subject: [PATCH] Subscribe to tracks in join response

---
 components/livekit/core/engine.c | 12 +++++++++++-
 components/livekit/core/engine.h |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/components/livekit/core/engine.c b/components/livekit/core/engine.c
index e0288ac..cafee2e 100644
--- a/components/livekit/core/engine.c
+++ b/components/livekit/core/engine.c
@@ -153,7 +153,7 @@ static engine_err_t subscribe_tracks(engine_t *eng, livekit_pb_track_info_t *tra
         return ENGINE_ERR_INVALID_ARG;
     }
     if (eng->session.sub_audio_track_sid[0] != '\0') {
-        return ENGINE_ERR_NONE;
+        return ENGINE_ERR_MAX_SUB;
     }
     for (int i = 0; i < count; i++) {
         livekit_pb_track_info_t *track = &tracks[i];
@@ -689,6 +689,16 @@ static bool handle_join(engine_t *eng, const livekit_pb_join_response_t *join)
         ESP_LOGE(TAG, "Failed to establish peer connections");
         return false;
     }
+
+    // 6. Subscribe to remote tracks that have already been published.
+    for (pb_size_t i = 0; i < join->other_participants_count; i++) {
+        engine_err_t ret = subscribe_tracks(
+            eng,
+            join->other_participants[i].tracks,
+            join->other_participants[i].tracks_count
+        );
+        if (ret == ENGINE_ERR_MAX_SUB) break;
+    }
     return true;
 }
 
diff --git a/components/livekit/core/engine.h b/components/livekit/core/engine.h
index 8916af7..048feb0 100644
--- a/components/livekit/core/engine.h
+++ b/components/livekit/core/engine.h
@@ -35,6 +35,7 @@ typedef enum {
     ENGINE_ERR_RTC         = -4,
     ENGINE_ERR_MEDIA       = -5,
     ENGINE_ERR_OTHER       = -6,
+    ENGINE_ERR_MAX_SUB     = -7, // No more subscriptions allowed.
     // TODO: Add more error cases as needed
 } engine_err_t;