Merge pull request #37 from johnboiles/master

Adding level metering APIs. Adding casts to get rid of Xcode warnings.

Audjustable/Classes/AudioPlayer/AudioPlayer.h

@@ -172,6 +172,10 @@ AudioQueueBufferRefLookupEntry;
     volatile BOOL audioQueueFlushing;
     volatile SInt64 audioPacketsReadCount;
     volatile SInt64 audioPacketsPlayedCount;
+
+    BOOL meteringEnabled;
+    AudioQueueLevelMeterState *levelMeterState;
+    NSInteger numberOfChannels;
 }
 
 @property (readonly) double duration;
@@ -179,6 +183,8 @@ AudioQueueBufferRefLookupEntry;
 @property (readwrite) AudioPlayerState state;
 @property (readonly) AudioPlayerStopReason stopReason;
 @property (readwrite, unsafe_unretained) id<AudioPlayerDelegate> delegate;
+//! Turns level metering on or off. Default is off
+@property(getter=isMeteringEnabled) BOOL meteringEnabled;
 
 -(id) init;
 -(id) initWithNumberOfAudioQueueBuffers:(int)numberOfAudioQueueBuffers andReadBufferSize:(int)readBufferSizeIn;
@@ -195,5 +201,11 @@ AudioQueueBufferRefLookupEntry;
 -(void) unmute;
 -(void) dispose;
 -(NSObject*) currentlyPlayingQueueItemId;
+//! Call to refresh meter values
+- (void) updateMeters;
+//! Returns peak power in decibels for a given channel
+- (float) peakPowerForChannel:(NSUInteger)channelNumber;
+//! Returns average power in decibels for a given channel
+- (float) averagePowerForChannel:(NSUInteger)channelNumber;
 
 @end

Audjustable/Classes/AudioPlayer/AudioPlayer.m

@@ -451,6 +451,7 @@ static void AudioQueueIsRunningCallbackProc(void* userData, AudioQueueRef audioQ
     free(packetDescs);
     free(audioQueueBuffer);
     free(audioQueueBufferLookup);
+    free(levelMeterState);
 }
 
 -(void) startSystemBackgroundTask
@@ -733,7 +734,7 @@ static void AudioQueueIsRunningCallbackProc(void* userData, AudioQueueRef audioQ
             
             if (currentlyReadingEntry->processedPacketsSizeTotal < 0xfffff)
             {
-                OSAtomicAdd32(packetSize, &currentlyReadingEntry->processedPacketsSizeTotal);
+                OSAtomicAdd32((int32_t)packetSize, &currentlyReadingEntry->processedPacketsSizeTotal);
                 OSAtomicIncrement32(&currentlyReadingEntry->processedPacketsCount);
             }
             
@@ -1215,6 +1216,9 @@ static void AudioQueueIsRunningCallbackProc(void* userData, AudioQueueRef audioQ
     
     AudioQueueSetParameter(audioQueue, kAudioQueueParam_Volume, 1);
     
+    // Re set metering enabled in case the user set it before the queue was created
+    [self setMeteringEnabled:meteringEnabled];
+
     free(cookieData);
 }
 
@@ -2179,4 +2183,55 @@ static void AudioQueueIsRunningCallbackProc(void* userData, AudioQueueRef audioQ
     return retval;
 }
 
+#pragma mark Metering
+
+-(void) setMeteringEnabled:(BOOL)enabled
+{
+    // If the audioQueue isn't already created, set the property for later
+    if (!audioQueue) {
+        meteringEnabled = enabled;
+        return;
+    }
+    UInt32 on = enabled ? 1 : 0;
+    OSStatus error = AudioQueueSetProperty(audioQueue, kAudioQueueProperty_EnableLevelMetering, &on, sizeof(on));
+    if (error) {
+        meteringEnabled = NO;
+    } else {
+        meteringEnabled = YES;
+    }
+}
+
+-(BOOL) isMeteringEnabled
+{
+    return meteringEnabled;
+}
+
+-(void) updateMeters
+{
+    if (!meteringEnabled) NSAssert(NO, @"Metering is not enabled. Make sure to set meteringEnabled = YES.");
+
+    NSInteger channels = currentAudioStreamBasicDescription.mChannelsPerFrame;
+    if (numberOfChannels != channels) {
+        numberOfChannels = channels;
+        if (levelMeterState) free(levelMeterState);
+        levelMeterState = malloc(sizeof(AudioQueueLevelMeterState) * numberOfChannels);
+    }
+
+    UInt32 sizeofMeters = sizeof(AudioQueueLevelMeterState) * numberOfChannels;
+
+    AudioQueueGetProperty(audioQueue, kAudioQueueProperty_CurrentLevelMeterDB, levelMeterState, &sizeofMeters);
+}
+
+-(float) peakPowerForChannel:(NSUInteger)channelNumber
+{
+    if (!meteringEnabled || !levelMeterState || (channelNumber > numberOfChannels)) return 0;
+    return levelMeterState[channelNumber].mPeakPower;
+}
+
+-(float) averagePowerForChannel:(NSUInteger)channelNumber
+{
+    if (!meteringEnabled || !levelMeterState || (channelNumber > numberOfChannels)) return 0;
+    return levelMeterState[channelNumber].mAveragePower;
+}
+
 @end

Audjustable/Classes/AudioPlayer/HttpDataSource.m

@@ -153,7 +153,7 @@
     
     stream = 0;
     relativePosition = 0;
-    seekStart = offset;
+    seekStart = (int)offset;
     
     [self open];
     [self reregisterForEvents];