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Added audio frame filtering and level metering support using Audio Units

This commit is contained in:
Thong Nguyen 2014-02-01 23:04:55 +00:00
parent 98c7d9b8f0
commit 4d73784338
5 changed files with 192 additions and 9 deletions
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2
ExampleApp/ExampleApp/AppDelegate.m
View File

@ -33,6 +33,8 @@
self.window.backgroundColor = [UIColor whiteColor];
audioPlayer = [[STKAudioPlayer alloc] init];
audioPlayer.meteringEnabled = YES;
AudioPlayerView* audioPlayerView = [[AudioPlayerView alloc] initWithFrame:self.window.bounds];
audioPlayerView.delegate = self;

1
ExampleApp/ExampleApp/AudioPlayerView.h
View File

@ -58,6 +58,7 @@
UIButton* queueShortFileButton;
UIButton* queuePcmWaveFileFromHTTPButton;
UIButton* playFromLocalFileButton;
UIView* meter;
}
@property (readwrite, retain) STKAudioPlayer* audioPlayer;

12
ExampleApp/ExampleApp/AudioPlayerView.m
View File

@ -101,6 +101,11 @@
statusLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, slider.frame.origin.y + slider.frame.size.height + label.frame.size.height + 8, frame.size.width, 50)];
statusLabel.textAlignment = NSTextAlignmentCenter;
meter = [[UIView alloc] initWithFrame:CGRectMake(0, 460, 0, 20)];
meter.backgroundColor = [UIColor greenColor];
[self addSubview:slider];
[self addSubview:playButton];
@ -112,6 +117,7 @@
[self addSubview:label];
[self addSubview:statusLabel];
[self addSubview:stopButton];
[self addSubview:meter];
[self setupTimer];
[self updateControls];
@ -134,7 +140,7 @@
-(void) setupTimer
{
timer = [NSTimer timerWithTimeInterval:0.05 target:self selector:@selector(tick) userInfo:nil repeats:YES];
timer = [NSTimer timerWithTimeInterval:0.01 target:self selector:@selector(tick) userInfo:nil repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
}
@ -168,6 +174,10 @@
}
statusLabel.text = audioPlayer.state == STKAudioPlayerStateBuffering ? @"buffering" : @"";
CGFloat newWidth = 320 * (([audioPlayer peakPowerInDecibelsForChannel:1] + 60) / 60);
meter.frame = CGRectMake(0, 460, newWidth, 20);
}
-(void) playFromHTTPButtonTouched

11
StreamingKit/StreamingKit/STKAudioPlayer.h
View File

@ -118,12 +118,13 @@ STKAudioPlayerOptions;
@end
typedef void(^STKFrameFilter)(UInt32 channelsPerFrame, UInt32 bytesPerFrame, UInt32 frameCount, UInt32* frames);
typedef void(^STKFrameFilter)(UInt32 channelsPerFrame, UInt32 bytesPerFrame, UInt32 frameCount, void* frames);
@interface STKAudioPlayer : NSObject<STKDataSourceDelegate>
@property (readonly) double duration;
@property (readonly) double progress;
@property (readwrite) BOOL meteringEnabled;
@property (readonly) NSArray* frameFilters;
@property (readwrite) STKAudioPlayerState state;
@property (readonly) STKAudioPlayerOptions options;
@ -167,7 +168,11 @@ typedef void(^STKFrameFilter)(UInt32 channelsPerFrame, UInt32 bytesPerFrame, UIn
/// The QueueItemId of the currently playing item
-(NSObject*) currentlyPlayingQueueItemId;
-(void) appendFrameFilter:(STKFrameFilter)frameFilter withName:(NSString*)name;
-(void) addFrameFilter:(STKFrameFilter)frameFilter withName:(NSString*)name afterFilterWithName:(NSString*)afterFilterWithName;
-(void) removeFrameFilterWithName:(NSString*)name;
-(void) appendFrameFilterWithName:(NSString*)name block:(STKFrameFilter)block;
-(void) addFrameFilterWithName:(NSString*)name afterFilterWithName:(NSString*)afterFilterWithName block:(STKFrameFilter)block;
-(float) peakPowerInDecibelsForChannel:(NSUInteger)channelNumber;
-(float) averagePowerInDecibelsForChannel:(NSUInteger)channelNumber;
@end

175
StreamingKit/StreamingKit/STKAudioPlayer.m
View File

@ -41,6 +41,10 @@
#import "NSMutableArray+STKAudioPlayer.h"
#import "libkern/OSAtomic.h"
#define STK_DBMIN (-60)
#define STK_DBOFFSET (-74.0)
#define STK_LOWPASSFILTERTIMESLICE (0.0005)
#define STK_DEFAULT_PCM_BUFFER_SIZE_IN_SECONDS (10)
#define STK_DEFAULT_SECONDS_REQUIRED_TO_START_PLAYING (0.1)
#define STK_MAX_COMPRESSED_PACKETS_FOR_BITRATE_CALCULATION (2048)
@ -79,8 +83,11 @@
UInt8* readBuffer;
int readBufferSize;
Float32 peakPowerDb[2];
Float32 averagePowerDb[2];
BOOL meteringEnabled;
STKAudioPlayerOptions options;
AudioComponentInstance audioUnit;
UInt32 framesRequiredToStartPlaying;
@ -280,7 +287,7 @@ static void AudioFileStreamPacketsProc(void* clientData, UInt32 numberBytes, UIn
pcmAudioBufferList.mBuffers[0].mDataByteSize = (canonicalAudioStreamBasicDescription.mSampleRate * STK_DEFAULT_PCM_BUFFER_SIZE_IN_SECONDS) * canonicalAudioStreamBasicDescription.mBytesPerFrame;
pcmAudioBufferList.mBuffers[0].mData = (void*)calloc(pcmAudioBuffer->mDataByteSize, 1);
pcmAudioBufferList.mBuffers[0].mNumberChannels = 2;
pcmBufferFrameSizeInBytes = canonicalAudioStreamBasicDescription.mBytesPerFrame;
pcmBufferTotalFrameCount = pcmAudioBuffer->mDataByteSize / pcmBufferFrameSizeInBytes;
@ -304,6 +311,8 @@ static void AudioFileStreamPacketsProc(void* clientData, UInt32 numberBytes, UIn
upcomingQueue = [[NSMutableArray alloc] init];
bufferingQueue = [[NSMutableArray alloc] init];
[self resetPcmBuffers];
[self createAudioUnit];
[self createPlaybackThread];
@ -1415,6 +1424,10 @@ static void AudioFileStreamPacketsProc(void* clientData, UInt32 numberBytes, UIn
self->pcmBufferFrameStartIndex = 0;
self->pcmBufferUsedFrameCount = 0;
self->peakPowerDb[0] = STK_DBMIN;
self->peakPowerDb[1] = STK_DBMIN;
self->averagePowerDb[0] = STK_DBMIN;
self->averagePowerDb[1] = STK_DBMIN;
OSSpinLockUnlock(&pcmBufferSpinLock);
}
@ -1734,6 +1747,8 @@ static BOOL GetHardwareCodecClassDesc(UInt32 formatId, AudioClassDescription* cl
}
status = AudioOutputUnitStop(audioUnit);
[self resetPcmBuffers];
if (status)
{
@ -2237,14 +2252,162 @@ static OSStatus OutputRenderCallback(void* inRefCon, AudioUnitRenderActionFlags*
return 0;
}
-(float) peakPowerInDecibelsForChannel:(NSUInteger)channelNumber
{
if (channelNumber >= canonicalAudioStreamBasicDescription.mChannelsPerFrame)
{
return 0;
}
return peakPowerDb[channelNumber];
}
-(float) averagePowerInDecibelsForChannel:(NSUInteger)channelNumber
{
if (channelNumber >= canonicalAudioStreamBasicDescription.mChannelsPerFrame)
{
return 0;
}
return averagePowerDb[channelNumber];
}
-(BOOL) meteringEnabled
{
return self->meteringEnabled;
}
#define CALCULATE_METER(channel) \
Float32 currentFilteredValueOfSampleAmplitude##channel = STK_LOWPASSFILTERTIMESLICE * absoluteValueOfSampleAmplitude##channel + (1.0 - STK_LOWPASSFILTERTIMESLICE) * previousFilteredValueOfSampleAmplitude##channel; \
previousFilteredValueOfSampleAmplitude##channel = currentFilteredValueOfSampleAmplitude##channel; \
Float32 sampleDB##channel = 20.0 * log10(currentFilteredValueOfSampleAmplitude##channel) + STK_DBOFFSET; \
if ((sampleDB##channel == sampleDB##channel) && (sampleDB##channel != -DBL_MAX)) \
{ \
if(sampleDB##channel > peakValue##channel) \
{ \
peakValue##channel = MIN(sampleDB##channel, 0); \
} \
if (sampleDB##channel > -DBL_MAX) \
{ \
totalValue##channel += sampleDB##channel; \
} \
decibels##channel = peakValue##channel; \
};
-(void) setMeteringEnabled:(BOOL)value
{
if (self->meteringEnabled == value)
{
return;
}
if (!value)
{
[self removeFrameFilterWithName:@"STKMeteringFilter"];
self->meteringEnabled = NO;
}
else
{
[self appendFrameFilterWithName:@"STKMeteringFilter" block:^(UInt32 channelsPerFrame, UInt32 bytesPerFrame, UInt32 frameCount, void* frames)
{
SInt16* samples = (SInt16*)frames;
Float32 decibelsLeft = STK_DBMIN;
Float32 peakValueLeft = STK_DBMIN;
Float64 totalValueLeft = STK_DBMIN;
Float32 previousFilteredValueOfSampleAmplitudeLeft = 0;
Float32 decibelsRight = STK_DBMIN;
Float32 peakValueRight = STK_DBMIN;
Float64 totalValueRight = STK_DBMIN;
Float32 previousFilteredValueOfSampleAmplitudeRight = 0;
for (int i = 0; i < frameCount * 2; i++)
{
Float32 absoluteValueOfSampleAmplitudeLeft = abs(samples[i]);
Float32 absoluteValueOfSampleAmplitudeRight = abs(samples[i]);
CALCULATE_METER(Left);
CALCULATE_METER(Right);
}
peakPowerDb[0] = MIN(MAX(decibelsLeft, -60), 0);
averagePowerDb[0] = MIN(MAX(totalValueLeft / frameCount, -60), 0);
peakPowerDb[1] = MIN(MAX(decibelsRight, -60), 0);
averagePowerDb[1] = MIN(MAX(totalValueRight / frameCount, -60), 0);
}];
}
}
-(NSArray*) frameFilters
{
return frameFilters;
}
-(void) appendFrameFilter:(STKFrameFilter)frameFilter withName:(NSString*)name
-(void) appendFrameFilterWithName:(NSString*)name block:(STKFrameFilter)block
{
[self addFrameFilter:frameFilter withName:name afterFilterWithName:nil];
[self addFrameFilterWithName:name afterFilterWithName:nil block:block];
}
-(void) removeFrameFilterWithName:(NSString*)name
{
pthread_mutex_lock(&self->playerMutex);
NSMutableArray* newFrameFilters = [[NSMutableArray alloc] initWithCapacity:frameFilters.count + 1];
for (STKFrameFilterEntry* filterEntry in frameFilters)
{
if (![filterEntry->name isEqualToString:name])
{
[newFrameFilters addObject:filterEntry];
}
}
NSArray* replacement = [NSArray arrayWithArray:newFrameFilters];
OSSpinLockLock(&pcmBufferSpinLock);
if (newFrameFilters.count > 0)
{
frameFilters = replacement;
}
else
{
frameFilters = nil;
}
OSSpinLockUnlock(&pcmBufferSpinLock);
pthread_mutex_unlock(&self->playerMutex);
}
-(void) addFrameFilterWithName:(NSString*)name afterFilterWithName:(NSString*)afterFilterWithName block:(STKFrameFilter)block
{
pthread_mutex_lock(&self->playerMutex);
NSMutableArray* newFrameFilters = [[NSMutableArray alloc] initWithCapacity:frameFilters.count + 1];
if (afterFilterWithName == nil)
{
[newFrameFilters addObject:[[STKFrameFilterEntry alloc] initWithFilter:block andName:name]];
[newFrameFilters addObjectsFromArray:frameFilters];
}
else
{
for (STKFrameFilterEntry* filterEntry in frameFilters)
{
if (afterFilterWithName != nil && [filterEntry->name isEqualToString:afterFilterWithName])
{
[newFrameFilters addObject:[[STKFrameFilterEntry alloc] initWithFilter:block andName:name]];
}
[newFrameFilters addObject:filterEntry];
}
}
NSArray* replacement = [NSArray arrayWithArray:newFrameFilters];
OSSpinLockLock(&pcmBufferSpinLock);
frameFilters = replacement;
OSSpinLockUnlock(&pcmBufferSpinLock);
pthread_mutex_unlock(&self->playerMutex);
}
-(void) addFrameFilter:(STKFrameFilter)frameFilter withName:(NSString*)name afterFilterWithName:(NSString*)afterFilterWithName
@ -2271,8 +2434,10 @@ static OSStatus OutputRenderCallback(void* inRefCon, AudioUnitRenderActionFlags*
}
}
NSArray* replacement = [NSArray arrayWithArray:newFrameFilters];
OSSpinLockLock(&pcmBufferSpinLock);
frameFilters = [NSArray arrayWithArray:newFrameFilters];
frameFilters = replacement;
OSSpinLockUnlock(&pcmBufferSpinLock);
pthread_mutex_unlock(&self->playerMutex);