CoreAudio: fix mapping of 7.1 surround channels (was Ls Rs Rls Rrs, now Rls Rrs Ls Rs).

CoreAudio: change 5.1 to use back surrounds instead of side to match how Sunshine configures the virtual 5.1 layout.

Author: andygrundman

app/streaming/audio/renderers/coreaudio/au_spatial_renderer.mm

@@ -148,10 +148,12 @@ OSStatus inputCallback(void *inRefCon,
             layout = kAudioChannelLayoutTag_Stereo;
             break;
         case 6:
-            layout = kAudioChannelLayoutTag_AudioUnit_5_1; // L R C LFE Ls Rs
+            // Back in the DVD era I remember 5.1 meant side surrounds (WAVE_5_1_A), but at some point it became back surrounds?
+            // layout = kAudioChannelLayoutTag_WAVE_5_1_A; // L R C LFE Ls Rs
+            layout = kAudioChannelLayoutTag_WAVE_5_1_B; // L R C LFE Rls Rrs
             break;
         case 8:
-            layout = kAudioChannelLayoutTag_AudioUnit_7_1; // L R C LFE Ls Rs Rls Rrs
+            layout = kAudioChannelLayoutTag_WAVE_7_1; // L R C LFE Rls Rrs Ls Rs
             break;
         case 12:
             layout = kAudioChannelLayoutTag_Atmos_7_1_4; // L R C LFE Ls Rs Rls Rrs Vhl Vhr Ltr Rtr
@@ -161,6 +163,8 @@ OSStatus inputCallback(void *inRefCon,
             return false;
     }
 
+    // XXX Allow user to override channel layout
+
     status = setStreamFormatAndACL(sampleRate, layout, kAudioUnitScope_Input, 0);
     if (status != noErr) {
         CA_LogError(status, "Failed to set AUSpatialRenderer input stream format to %d channels", inChannelCount);