Support for Channel Mapping

EZAudio/EZOutput.h

@@ -303,6 +303,16 @@ FOUNDATION_EXPORT Float64 const EZOutputDefaultSampleRate;
  */
 @property (nonatomic, strong, readwrite) EZAudioDevice *device;
 
+
+///-----------------------------------------------------------
+/// @name Getting/Setting The Output's Channel Mapping
+///-----------------------------------------------------------
+
+/**
+ The receiver’s audio-channel–to–device–channel mappings.
+ */
+@property (nonatomic, strong, readwrite) NSArray *channelMapping;
+
 //------------------------------------------------------------------------------
 #pragma mark - Actions
 //------------------------------------------------------------------------------

EZAudio/EZOutput.m

@@ -537,6 +537,7 @@ - (void)setDevice:(EZAudioDevice *)device
                                                        &deviceId,
                                                        sizeof(AudioDeviceID))
                         operation:"Couldn't set default device on I/O unit"];
+
 #endif
 
     // store device
@@ -551,6 +552,65 @@ - (void)setDevice:(EZAudioDevice *)device
 
 //------------------------------------------------------------------------------
 
+- (void)setChannelMapping:(NSArray *)channelMapping {
+
+#if TARGET_OS_MAC
+
+    if (channelMapping && _device) {
+
+        //
+        // Channel mapping
+        //
+
+        NSInteger channelCount = _device.outputChannelCount;
+
+        if ([channelMapping count]<= channelCount) {
+
+
+
+            // create the C array which will contain the channel mapping table
+            UInt32 channelMap[channelCount];
+
+            // first of all clear the current mapping table
+            for (NSInteger i=0;i<_device.outputChannelCount;i++) {
+
+                channelMap[i] = -1;
+
+            }
+
+            // set the new values
+            for (int i=0;i<[channelMapping count];i++) {
+
+                channelMap[[[channelMapping objectAtIndex:i] unsignedIntValue]] = i;
+
+            }
+
+            UInt32 propertySize = (int)channelCount*sizeof(UInt32);
+
+            [EZAudioUtilities checkResult:AudioUnitSetProperty(self.info->outputNodeInfo.audioUnit,
+                                                               kAudioOutputUnitProperty_ChannelMap,
+                                                               kAudioUnitScope_Global,
+                                                               0,
+                                                               &channelMap,
+                                                               propertySize)
+                                operation:"Couldn't set channel mapping"];
+
+
+            // store channel mapping
+            _channelMapping = channelMapping;
+
+        }
+
+
+    }
+
+
+#endif
+
+}
+
+//------------------------------------------------------------------------------
+
 - (void)setInputFormat:(AudioStreamBasicDescription)inputFormat
 {
     self.info->inputFormat = inputFormat;

EZAudioExamples/OSX/EZAudioPlayFileExample/EZAudioPlayFileExample/PlayFileViewController.h

@@ -106,6 +106,11 @@
  */
 @property (nonatomic, weak) IBOutlet NSPopUpButton *outputDevicePopUpButton;
 
+/**
+ The microphone pop up button (contains the menu for choosing a microphone input)
+ */
+@property (nonatomic, weak) IBOutlet NSPopUpButton *outputChannelMappingPopUpButton;
+
 #pragma mark - Actions
 /**
  Switches the plot drawing type between a buffer plot (visualizes the current stream of audio data from the update function) or a rolling plot (visualizes the audio data over time, this is the classic waveform look)

EZAudioExamples/OSX/EZAudioPlayFileExample/EZAudioPlayFileExample/PlayFileViewController.m

@@ -71,6 +71,7 @@ - (void)awakeFromNib
     // Reload the menu for the output device selector popup button
     //
     [self reloadOutputDevicePopUpButtonMenu];
+    [self reloadOutputChannelMappingPopUpButtonMenu];
 
     //
     // Configure UI components
@@ -89,7 +90,8 @@ - (void)awakeFromNib
     //
     // Try opening the sample file
     //
-    [self openFileWithFilePathURL:[NSURL fileURLWithPath:kAudioFileDefault]];
+  //  [self openFileWithFilePathURL:[NSURL fileURLWithPath:kAudioFileDefault]];
+    [self openFileWithFilePathURL:[NSURL fileURLWithPath:@"/Users/tamasnagy/Desktop/asztal/testloops/Mitti Test Loops/Hebopula Hap HD.mov"]];
 }
 
 //------------------------------------------------------------------------------
@@ -158,10 +160,23 @@ - (void)changedOutput:(NSMenuItem *)item
 {
     EZAudioDevice *device = [item representedObject];
     [self.player setDevice:device];
+
+    [self reloadOutputChannelMappingPopUpButtonMenu];
 }
 
 //------------------------------------------------------------------------------
 
+- (void)changedChannelMapping:(NSMenuItem *)item
+{
+
+    NSArray *mapping = [item representedObject];
+    [self.player.output setChannelMapping:mapping];
+
+}
+
+//------------------------------------------------------------------------------
+
+
 - (void)changePlotType:(id)sender
 {
     NSInteger selectedSegment = [sender selectedSegment];
@@ -368,6 +383,31 @@ - (void)reloadOutputDevicePopUpButtonMenu
     [self.outputDevicePopUpButton selectItem:defaultOutputDeviceItem];
 }
 
+- (void)reloadOutputChannelMappingPopUpButtonMenu {
+
+    [[self outputChannelMappingPopUpButton] removeAllItems];
+
+    NSInteger outputchannels = [[self.player device] outputChannelCount];
+
+    NSMenu *menu = [[NSMenu alloc] init];
+
+    for (NSInteger i=0;i<outputchannels;i+=2) {
+
+        NSMenuItem *item = [[NSMenuItem alloc] initWithTitle:[NSString stringWithFormat:@"%ld & %ld", i+1, i+2]
+                                                      action:@selector(changedChannelMapping:)
+                                               keyEquivalent:@""];
+
+        item.representedObject = [NSArray arrayWithObjects:[NSNumber numberWithInteger:i],[NSNumber numberWithInteger:i+1], nil];
+        item.target = self;
+        [menu addItem:item];
+    }
+
+
+    self.outputChannelMappingPopUpButton.menu = menu;
+    [self.outputChannelMappingPopUpButton selectItem:[[menu itemArray] firstObject]];
+
+}
+
 //------------------------------------------------------------------------------
 #pragma mark - EZAudioPlayerDelegate
 //------------------------------------------------------------------------------