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//
// SCListener 1.0.1
// http://github.com/stephencelis/sc_listener
//
// (c) 2009-* Stephen Celis, <stephen@stephencelis.com>.
// Released under the MIT License.
//
#import "SCListener.h"
@interface SCListener (Private)
- (void)updateLevels;
- (void)setupQueue;
- (void)setupFormat;
- (void)setupBuffers;
- (void)setupMetering;
@end
static SCListener *sharedListener = nil;
static void listeningCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer, const AudioTimeStamp *inStartTime, UInt32 inNumberPacketsDescriptions, const AudioStreamPacketDescription *inPacketDescs) {
SCListener *listener = (SCListener *)inUserData;
if ([listener isListening])
AudioQueueEnqueueBuffer(inAQ, inBuffer, 0, NULL);
}
@implementation SCListener
+ (SCListener *)sharedListener {
@synchronized(self) {
if (sharedListener == nil)
[[self alloc] init];
}
return sharedListener;
}
- (void)dealloc {
[sharedListener stop];
[super dealloc];
}
#pragma mark -
#pragma mark Listening
- (void)listen {
if (queue == nil)
[self setupQueue];
AudioQueueStart(queue, NULL);
}
- (void)pause {
if (![self isListening])
return;
AudioQueueStop(queue, true);
}
- (void)stop {
if (queue == nil)
return;
AudioQueueDispose(queue, true);
queue = nil;
}
- (BOOL)isListening {
if (queue == nil)
return NO;
UInt32 isListening, ioDataSize = sizeof(UInt32);
OSStatus result = AudioQueueGetProperty(queue, kAudioQueueProperty_IsRunning, &isListening, &ioDataSize);
return (result != noErr) ? NO : isListening;
}
#pragma mark -
#pragma mark Levels getters
- (Float32)averagePower {
if (![self isListening])
return 0.0;
return [self levels][0].mAveragePower;
}
- (Float32)peakPower {
if (![self isListening])
return 0.0;
return [self levels][0].mPeakPower;
}
- (AudioQueueLevelMeterState *)levels {
if (![self isListening])
return nil;
[self updateLevels];
return levels;
}
- (void)updateLevels {
UInt32 ioDataSize = format.mChannelsPerFrame * sizeof(AudioQueueLevelMeterState);
AudioQueueGetProperty(queue, (AudioQueuePropertyID)kAudioQueueProperty_CurrentLevelMeter, levels, &ioDataSize);
}
#pragma mark -
#pragma mark Setup
- (void)setupQueue {
if (queue)
return;
[self setupFormat];
[self setupBuffers];
AudioQueueNewInput(&format, listeningCallback, self, NULL, NULL, 0, &queue);
[self setupMetering];
}
- (void)setupFormat {
#if TARGET_IPHONE_SIMULATOR
format.mSampleRate = 44100.0;
#else
UInt32 ioDataSize = sizeof(sampleRate);
AudioSessionGetProperty(kAudioSessionProperty_CurrentHardwareSampleRate, &ioDataSize, &sampleRate);
format.mSampleRate = sampleRate;
#endif
format.mFormatID = kAudioFormatLinearPCM;
format.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
format.mFramesPerPacket = format.mChannelsPerFrame = 1;
format.mBitsPerChannel = 16;
format.mBytesPerPacket = format.mBytesPerFrame = 2;
}
- (void)setupBuffers {
AudioQueueBufferRef buffers[3];
for (NSInteger i = 0; i < 3; ++i) {
AudioQueueAllocateBuffer(queue, 735, &buffers[i]);
AudioQueueEnqueueBuffer(queue, buffers[i], 0, NULL);
}
}
- (void)setupMetering {
levels = (AudioQueueLevelMeterState *)calloc(sizeof(AudioQueueLevelMeterState), format.mChannelsPerFrame);
UInt32 trueValue = true;
AudioQueueSetProperty(queue, kAudioQueueProperty_EnableLevelMetering, &trueValue, sizeof(UInt32));
}
#pragma mark -
#pragma mark Singleton Pattern
+ (id)allocWithZone:(NSZone *)zone {
@synchronized(self) {
if (sharedListener == nil) {
sharedListener = [super allocWithZone:zone];
return sharedListener;
}
}
return nil;
}
- (id)copyWithZone:(NSZone *)zone {
return self;
}
- (id)init {
if ([super init] == nil)
return nil;
return self;
}
- (id)retain {
return self;
}
- (unsigned)retainCount {
return UINT_MAX;
}
- (void)release {
// Do nothing.
}
- (id)autorelease {
return self;
}
@end
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