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#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>
#import "GBAudioClient.h"
static OSStatus render(
GBAudioClient *self,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData)
{
GB_sample_t *buffer = (GB_sample_t *)ioData->mBuffers[0].mData;
self.renderBlock(self.rate, inNumberFrames, buffer);
return noErr;
}
@implementation GBAudioClient
{
AudioComponentInstance audioUnit;
}
- (id)initWithRendererBlock:(void (^)(UInt32 sampleRate, UInt32 nFrames, GB_sample_t *buffer)) block
andSampleRate:(UInt32) rate
{
if (!(self = [super init])) {
return nil;
}
// Configure the search parameters to find the default playback output unit
// (called the kAudioUnitSubType_RemoteIO on iOS but
// kAudioUnitSubType_DefaultOutput on Mac OS X)
AudioComponentDescription defaultOutputDescription;
defaultOutputDescription.componentType = kAudioUnitType_Output;
#if TARGET_OS_IPHONE
defaultOutputDescription.componentSubType = kAudioUnitSubType_RemoteIO;
#else
defaultOutputDescription.componentSubType = kAudioUnitSubType_DefaultOutput;
#endif
defaultOutputDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
defaultOutputDescription.componentFlags = 0;
defaultOutputDescription.componentFlagsMask = 0;
// Get the default playback output unit
AudioComponent defaultOutput = AudioComponentFindNext(NULL, &defaultOutputDescription);
if (!defaultOutput) {
NSLog(@"Can't find default output");
return nil;
}
// Create a new unit based on this that we'll use for output
OSErr err = AudioComponentInstanceNew(defaultOutput, &audioUnit);
if (!audioUnit) {
NSLog(@"Error creating unit: %hd", err);
return nil;
}
// Set our tone rendering function on the unit
AURenderCallbackStruct input;
input.inputProc = (void*)render;
input.inputProcRefCon = (__bridge void *)(self);
err = AudioUnitSetProperty(audioUnit,
kAudioUnitProperty_SetRenderCallback,
kAudioUnitScope_Input,
0,
&input,
sizeof(input));
if (err) {
NSLog(@"Error setting callback: %hd", err);
return nil;
}
AudioStreamBasicDescription streamFormat;
streamFormat.mSampleRate = rate;
streamFormat.mFormatID = kAudioFormatLinearPCM;
streamFormat.mFormatFlags =
kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked | kAudioFormatFlagsNativeEndian;
streamFormat.mBytesPerPacket = 4;
streamFormat.mFramesPerPacket = 1;
streamFormat.mBytesPerFrame = 4;
streamFormat.mChannelsPerFrame = 2;
streamFormat.mBitsPerChannel = 2 * 8;
err = AudioUnitSetProperty (audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
0,
&streamFormat,
sizeof(AudioStreamBasicDescription));
if (err) {
NSLog(@"Error setting stream format: %hd", err);
return nil;
}
err = AudioUnitInitialize(audioUnit);
if (err) {
NSLog(@"Error initializing unit: %hd", err);
return nil;
}
self.renderBlock = block;
_rate = rate;
return self;
}
-(void) start
{
OSErr err = AudioOutputUnitStart(audioUnit);
if (err) {
NSLog(@"Error starting unit: %hd", err);
return;
}
_playing = true;
}
-(void) stop
{
AudioOutputUnitStop(audioUnit);
_playing = false;
}
-(void) dealloc
{
[self stop];
AudioUnitUninitialize(audioUnit);
AudioComponentInstanceDispose(audioUnit);
}
@end
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