From 59bcf4697561017e8e3a15e5ac3bf244c0bd1bf5 Mon Sep 17 00:00:00 2001
From: Single <libobjc@gmail.com>
Date: Thu, 26 Dec 2019 18:48:22 +0800
Subject: [PATCH] SGAudioPlayer: Support for changing pitch.

---
 SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.h |  5 ++
 SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.m | 60 ++++++++++++++-----
 .../Classes/Core/SGRenderer/SGAudioRenderer.h |  9 ++-
 .../Classes/Core/SGRenderer/SGAudioRenderer.m | 25 ++++++++
 4 files changed, 84 insertions(+), 15 deletions(-)

diff --git a/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.h b/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.h
index 458b9c88..e281ae88 100644
--- a/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.h
+++ b/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.h
@@ -43,6 +43,11 @@
  */
 @property (nonatomic) float rate;
 
+/**
+ *  Pitch.
+ */
+@property (nonatomic) float pitch;
+
 /**
  *  Volume.
  */
diff --git a/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.m b/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.m
index a719d7f3..98f3aa13 100644
--- a/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.m
+++ b/SGPlayer/Classes/Core/SGAudio/SGAudioPlayer.m
@@ -21,6 +21,8 @@ @interface SGAudioPlayer ()
     AudioUnit _timePitchUnit;
 }
 
+@property (nonatomic, readonly) BOOL needsTimePitchNode;
+
 @end
 
 @implementation SGAudioPlayer
@@ -121,9 +123,18 @@ - (void)setup
     AUGraphSetNodeInputCallback(_graph, _mixerNode, 0, &inputCallbackStruct);
     AudioUnitAddRenderNotify(_outputUnit, outputCallback, (__bridge void *)self);
     
-    [self setRate:1];
-    [self setVolume:1];
+    AudioUnitParameterID mixerParam;
+#if SGPLATFORM_TARGET_OS_MAC
+    mixerParam = kStereoMixerParam_Volume;
+#elif SGPLATFORM_TARGET_OS_IPHONE_OR_TV
+    mixerParam = kMultiChannelMixerParam_Volume;
+#endif
+    AudioUnitGetParameter(_mixerUnit, mixerParam, kAudioUnitScope_Input, 0, &_volume);
+    AudioUnitGetParameter(_timePitchUnit, kNewTimePitchParam_Rate, kAudioUnitScope_Global, 0, &_rate);
+    AudioUnitGetParameter(_timePitchUnit, kNewTimePitchParam_Pitch, kAudioUnitScope_Global, 0, &_pitch);
+    
     [self setAsbd:asbd];
+    [self reconnectTimePitchNodeForce:YES];
 
     AUGraphInitialize(_graph);
 }
@@ -154,6 +165,24 @@ - (void)disconnectNodeInput:(AUNode)sourceNode destNode:(AUNode)destNode
     }
 }
 
+- (void)reconnectTimePitchNodeForce:(BOOL)force
+{
+    BOOL needsTimePitchNode = (_rate != 1.0) || (_pitch != 0.0);
+    if (_needsTimePitchNode != needsTimePitchNode || force) {
+        _needsTimePitchNode = needsTimePitchNode;
+        if (needsTimePitchNode) {
+            [self disconnectNodeInput:_mixerNode destNode:_outputNode];
+            AUGraphConnectNodeInput(_graph, _mixerNode, 0, _timePitchNode, 0);
+            AUGraphConnectNodeInput(_graph, _timePitchNode, 0, _outputNode, 0);
+        } else {
+            [self disconnectNodeInput:_mixerNode destNode:_timePitchNode];
+            [self disconnectNodeInput:_timePitchNode destNode:_outputNode];
+            AUGraphConnectNodeInput(_graph, _mixerNode, 0, _outputNode, 0);
+        }
+        AUGraphUpdate(_graph, NULL);
+    }
+}
+
 #pragma mark - Interface
 
 - (void)play
@@ -188,6 +217,9 @@ - (BOOL)isPlaying
 
 - (void)setVolume:(float)volume
 {
+    if (_volume == volume) {
+        return;
+    }
     AudioUnitParameterID param;
 #if SGPLATFORM_TARGET_OS_MAC
     param = kStereoMixerParam_Volume;
@@ -205,19 +237,19 @@ - (void)setRate:(float)rate
         return;
     }
     if (AudioUnitSetParameter(_timePitchUnit, kNewTimePitchParam_Rate, kAudioUnitScope_Global, 0, rate, 0) == noErr) {
-        if (_rate == 1.0 || rate == 1.0) {
-            if (rate == 1.0) {
-                [self disconnectNodeInput:_mixerNode destNode:_timePitchNode];
-                [self disconnectNodeInput:_timePitchNode destNode:_outputNode];
-                AUGraphConnectNodeInput(_graph, _mixerNode, 0, _outputNode, 0);
-            } else {
-                [self disconnectNodeInput:_mixerNode destNode:_outputNode];
-                AUGraphConnectNodeInput(_graph, _mixerNode, 0, _timePitchNode, 0);
-                AUGraphConnectNodeInput(_graph, _timePitchNode, 0, _outputNode, 0);
-            }
-            AUGraphUpdate(_graph, NULL);
-        }
         _rate = rate;
+        [self reconnectTimePitchNodeForce:NO];
+    }
+}
+
+- (void)setPitch:(float)pitch
+{
+    if (_pitch == pitch) {
+        return;
+    }
+    if (AudioUnitSetParameter(_timePitchUnit, kNewTimePitchParam_Pitch, kAudioUnitScope_Global, 0, pitch, 0) == noErr) {
+        _pitch = pitch;
+        [self reconnectTimePitchNodeForce:NO];
     }
 }
 
diff --git a/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.h b/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.h
index 2067b8f9..fb5c9acf 100644
--- a/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.h
+++ b/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.h
@@ -18,10 +18,17 @@
 */
 + (SGAudioDescriptor *)supportedAudioDescriptor;
 
+/*!
+ @property pitch
+ @abstract
+    Indicates the current pitch.
+ */
+@property (nonatomic) Float64 pitch;
+
 /*!
  @property volume
  @abstract
-    Indicates the current audio volume.
+    Indicates the current volume.
  */
 @property (nonatomic) Float64 volume;
 
diff --git a/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.m b/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.m
index 52fd97fe..feb64d90 100644
--- a/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.m
+++ b/SGPlayer/Classes/Core/SGRenderer/SGAudioRenderer.m
@@ -37,6 +37,7 @@ @interface SGAudioRenderer () <SGAudioPlayerDelegate>
 @implementation SGAudioRenderer
 
 @synthesize rate = _rate;
+@synthesize pitch = _pitch;
 @synthesize volume = _volume;
 @synthesize delegate = _delegate;
 @synthesize descriptor = _descriptor;
@@ -57,6 +58,7 @@ - (instancetype)initWithClock:(SGClock *)clock
     if (self = [super init]) {
         self->_clock = clock;
         self->_rate = 1.0;
+        self->_pitch = 0.0;
         self->_volume = 1.0;
         self->_lock = [[NSLock alloc] init];
         self->_capacity = SGCapacityCreate();
@@ -123,6 +125,28 @@ - (Float64)rate
     return ret;
 }
 
+- (void)setPitch:(Float64)pitch
+{
+    SGLockCondEXE11(self->_lock, ^BOOL {
+        return self->_pitch != pitch;
+    }, ^SGBlock {
+        self->_pitch = pitch;
+        return nil;
+    }, ^BOOL(SGBlock block) {
+        self->_player.pitch = pitch;
+        return YES;
+    });
+}
+
+- (Float64)pitch
+{
+    __block Float64 ret = 0.0f;
+    SGLockEXE00(self->_lock, ^{
+        ret = self->_pitch;
+    });
+    return ret;
+}
+
 - (void)setVolume:(Float64)volume
 {
     SGLockCondEXE11(self->_lock, ^BOOL {
@@ -164,6 +188,7 @@ - (BOOL)open
         self->_player = [[SGAudioPlayer alloc] init];
         self->_player.delegate = self;
         self->_player.rate = self->_rate;
+        self->_player.pitch = self->_pitch;
         self->_player.volume = self->_volume;
         return [self setState:SGRenderableStatePaused];
     }, nil);