fix: surround audio mapping between Gstreamer and Moonlight

games-on-whales · Aug 17, 2024 · 6cd2c72 · 6cd2c72
1 parent 75c7bd1
commit 6cd2c72
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Showing 2 changed files with 30 additions and 2 deletions.
diff --git a/src/moonlight-server/rtsp/commands.hpp b/src/moonlight-server/rtsp/commands.hpp
@@ -37,6 +37,7 @@ RTSP_PACKET ok_msg(int sequence_number,
 // Additional feature supports
 constexpr uint32_t FS_PEN_TOUCH_EVENTS = 0x01;
 constexpr uint32_t FS_CONTROLLER_TOUCH_EVENTS = 0x02;
+using namespace wolf::core::audio;
 
 RTSP_PACKET
 describe(const RTSP_PACKET &req, const state::StreamSession &session) {
@@ -48,12 +49,38 @@ describe(const RTSP_PACKET &req, const state::StreamSession &session) {
     payloads.push_back({"a", "a=rtpmap:98 AV1/90000"});
   }
 
+  auto mapping_p = session.audio_mode.speakers;
+  // Opusenc forces a re-mapping to Vorbis; see
+  // https://gitlab.freedesktop.org/gstreamer/gstreamer/-/blob/main/subprojects/gst-plugins-base/ext/opus/gstopusenc.c#L549-572
+  if (session.audio_mode.channels == 6) { // 5.1
+    mapping_p = {
+        // The mapping for 5.1 is: [0 1 4 5 2 3]
+        AudioMode::FRONT_LEFT,
+        AudioMode::FRONT_RIGHT,
+        AudioMode::BACK_LEFT,
+        AudioMode::BACK_RIGHT,
+        AudioMode::FRONT_CENTER,
+        AudioMode::LOW_FREQUENCY,
+    };
+  } else if (session.audio_mode.channels == 8) { // 7.1
+    mapping_p = {
+        // The mapping for 7.1 is: [0 1 4 5 2 3 6 7]
+        AudioMode::FRONT_LEFT,
+        AudioMode::FRONT_RIGHT,
+        AudioMode::BACK_LEFT,
+        AudioMode::BACK_RIGHT,
+        AudioMode::FRONT_CENTER,
+        AudioMode::LOW_FREQUENCY,
+        AudioMode::SIDE_LEFT,
+        AudioMode::SIDE_RIGHT,
+    };
+  }
+
   /**
    * GFE advertises incorrect mapping for normal quality configurations,
    * as a result, Moonlight rotates all channels from index '3' to the right
    * To work around this, rotate channels to the left from index '3'
    */
-  auto mapping_p = session.audio_mode.speakers;
   if (session.audio_mode.channels > 2) { // 5.1 and 7.1
     std::rotate(mapping_p.begin() + 3, mapping_p.begin() + 4, mapping_p.end());
   }

diff --git a/tests/testRTSP.cpp b/tests/testRTSP.cpp
@@ -12,6 +12,7 @@ using Catch::Matchers::Equals;
 using namespace std::string_literals;
 using namespace state;
 using namespace rtsp;
+using namespace wolf::core::audio;
 
 /**
  * In order to test rtsp::tcp_connection we create a derived class that does the opposite:
@@ -252,7 +253,7 @@ TEST_CASE("Custom Parser", "[RTSP]") {
 state::SessionsAtoms test_init_state() {
   StreamSession session = {
       .display_mode = {1920, 1080, 60},
-      .audio_mode = {2, 1, 1, {state::AudioMode::FRONT_LEFT, state::AudioMode::FRONT_RIGHT}},
+      .audio_mode = {2, 1, 1, {AudioMode::FRONT_LEFT, AudioMode::FRONT_RIGHT}},
       .app = std::make_shared<state::App>(state::App{.base = {},
                                                      .h264_gst_pipeline = "",
                                                      .hevc_gst_pipeline = "",