Add Link Audio Support To LinkHut

Author: fgo-ableton

LinkKit/LinkKitResources.bundle/en.lproj/Localizable.strings

@@ -14,6 +14,9 @@
 "EnableLinkAudioTitle" = "Share Audio";
 "EnableLinkAudioSubtitle" = "Share audio with Link peers";
 
+"PeerNameTitle" = "Peer Name";
+"PeerNameSubtitle" = "Other Link peers see that name";
+
 "ConnectedPeersSectionTitle" = "CONNECTED PEERS";
 
 "PeersConnectedZero" = "No peers connected";

examples/LinkHut/LinkHut/AudioEngine.m

@@ -6,6 +6,7 @@
 #include <mach/mach_time.h>
 #include "AudioEngine.h"
 #include <os/lock.h>
+#include "ABLLinkUtils.h"
 
 #define INVALID_BEAT_TIME DBL_MIN
 #define INVALID_BPM DBL_MIN
@@ -30,6 +31,7 @@
  */
 typedef struct {
     ABLLinkRef ablLink;
+    ABLLinkAudioSinkRef ablLinkAudioSink;
     // Shared between threads. Only write when engine not running.
     Float64 sampleRate;
     // Shared between threads. Only write when engine not running.
@@ -221,6 +223,14 @@ static OSStatus audioCallback(
             (SInt16*)ioData->mBuffers[0].mData);
     }
 
+    ABLLinkCommitCoreAudioBufferWithHostTime(
+      linkData->ablLinkAudioSink,
+      sessionState,
+      hostTimeAtBufferBegin,
+      linkData->localEngineData.quantum,
+      inNumberFrames,
+      ioData);
+
     return noErr;
 }
 
@@ -266,6 +276,13 @@ - (ABLLinkRef)linkRef {
     return _linkData.ablLink;
 }
 
+- (void)updateSinkAudioProperties {
+    AudioStreamBasicDescription asbd;
+    UInt32 dataSize = sizeof(asbd);
+    AudioUnitGetProperty(_ioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &asbd, &dataSize);
+    ABLLinkSetPropertiesFromASBD(_linkData.ablLinkAudioSink, &asbd);
+}
+
 # pragma mark - Handle AVAudioSession changes
 - (void)handleRouteChange:(NSNotification *)notification {
 #pragma unused(notification)
@@ -306,6 +323,8 @@ static void StreamFormatCallback(
             [engine start];
         }
     }
+
+    [engine updateSinkAudioProperties];
 }
 
 # pragma mark - create and delete engine
@@ -342,6 +361,7 @@ - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self
                                                     name:@"AVAudioSessionRouteChangeNotification"
                                                   object:[AVAudioSession sharedInstance]];
+    ABLLinkAudioSinkDelete(_linkData.ablLinkAudioSink);
     ABLLinkDelete(_linkData.ablLink);
 }
 
@@ -379,6 +399,7 @@ - (void)initLinkData:(Float64)bpm {
     mach_timebase_info(&timeInfo);
 
     _linkData.ablLink = ABLLinkNew(bpm);
+    _linkData.ablLinkAudioSink = ABLLinkAudioSinkNew(_linkData.ablLink, "metro", 8192);
     _linkData.sampleRate = [AVAudioSession sharedInstance].sampleRate;
     _linkData.secondsToHostTime = (1.0e9 * timeInfo.denom) / (Float64)timeInfo.numer;
     _linkData.sharedEngineData.outputLatency =
@@ -458,6 +479,8 @@ - (void)setupAudioEngine {
         (int)result,
         (const char *)(&result));
 
+    [self updateSinkAudioProperties];
+
     // Set Audio Callback
     AURenderCallbackStruct ioRemoteInput;
     ioRemoteInput.inputProc = audioCallback;

examples/LinkHut/LinkHut/Info.plist

@@ -4,6 +4,10 @@
 <dict>
 	<key>ABLLinkStartStopSyncSupported</key>
 	<true/>
+	<key>ABLLinkAudioSupported</key>
+	<true/>
+	<key>ABLLinkPeerName</key>
+	<string>LinkHut</string>
 	<key>CFBundleLocalizations</key>
 	<array>
 		<string>en</string>