Fix high-quality surround sound breaking audio when streaming over the Internet or IPv6

src/AudioStream.c

@@ -319,11 +319,13 @@ int startAudioStream(void* audioContext, int arFlags) {
     int err;
     OPUS_MULTISTREAM_CONFIGURATION chosenConfig;
 
+    // TODO: Get these from RTSP ANNOUNCE surround-params
     if (StreamConfig.audioConfiguration == AUDIO_CONFIGURATION_STEREO) {
         chosenConfig = opusStereoConfig;
     }
     else if (StreamConfig.audioConfiguration == AUDIO_CONFIGURATION_51_SURROUND) {
         if (HighQualitySurroundEnabled) {
+            LC_ASSERT(HighQualitySurroundSupported);
             chosenConfig = opus51HighSurroundConfig;
         }
         else {

src/Connection.c

@@ -18,6 +18,7 @@ DECODER_RENDERER_CALLBACKS VideoCallbacks;
 AUDIO_RENDERER_CALLBACKS AudioCallbacks;
 int NegotiatedVideoFormat;
 volatile int ConnectionInterrupted;
+int HighQualitySurroundSupported;
 int HighQualitySurroundEnabled;
 int OriginalVideoBitrate;
 int AudioPacketDuration;

src/Limelight-internal.h

@@ -20,6 +20,7 @@ extern DECODER_RENDERER_CALLBACKS VideoCallbacks;
 extern AUDIO_RENDERER_CALLBACKS AudioCallbacks;
 extern int NegotiatedVideoFormat;
 extern volatile int ConnectionInterrupted;
+extern int HighQualitySurroundSupported;
 extern int HighQualitySurroundEnabled;
 extern int OriginalVideoBitrate;
 extern int AudioPacketDuration;

src/RtspConnection.c

@@ -566,6 +566,15 @@ int performRtspHandshake(void) {
             NegotiatedVideoFormat = VIDEO_FORMAT_H264;
         }
 
+        // Check if high bitrate surround sound is available before attempting to request it.
+        // TODO: Parse these surround-params so we can get rid of our hardcoded Opus mappings
+        if (strstr(response.payload, "surround-params=660")) {
+            HighQualitySurroundSupported = 1;
+        }
+        else {
+            HighQualitySurroundSupported = 0;
+        }
+
         freeMessage(&response);
     }
 

src/SdpGenerator.c

@@ -362,7 +362,7 @@ static PSDP_OPTION getAttributesList(char*urlSafeAddr) {
     if (AppVersionQuad[0] >= 7) {
         // Decide to use HQ audio based on the original video bitrate, not the HEVC-adjusted value
         if (OriginalVideoBitrate >= HIGH_AUDIO_BITRATE_THRESHOLD && audioChannelCount > 2 &&
-                (AudioCallbacks.capabilities & CAPABILITY_SLOW_OPUS_DECODER) == 0) {
+                HighQualitySurroundSupported && (AudioCallbacks.capabilities & CAPABILITY_SLOW_OPUS_DECODER) == 0) {
             // Enable high quality mode for surround sound
             err |= addAttributeString(&optionHead, "x-nv-audio.surround.AudioQuality", "1");