Audio Unit file recording with aurioTouch - AudioStreamBasicDescription configuration issue? - ios

I've started down the path on learning Audio Unit with aurioTouch. After a few days of learning Audio Unit, I'm still feeling a bit lost and I think I'm missing something very obvious.
Full source can be view at: http://pastebin.com/LXLYDEhy
Also listed the partial source down here
In my performRender callback, I've changed the code to
static OSStatus performRender (void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
OSStatus err = noErr;
AudioController *audioController = (__bridge AudioController *)inRefCon;
AudioBufferList bufferList;
bufferList.mNumberBuffers = 1;
bufferList.mBuffers[0].mData = NULL;
OSStatus status;
status = AudioUnitRender(cd.rioUnit,
ioActionFlags,
inTimeStamp,
inBusNumber,
inNumberFrames,
&bufferList); // bufferList.mBuffers[0].mData is null
status = ExtAudioFileWriteAsync(audioController.extAudioFileRef, bufferList.mNumberBuffers, &bufferList);
}
The audio units are setup like this
- (AudioStreamBasicDescription)getAudioDescription {
AudioStreamBasicDescription audioDescription = {0};
audioDescription.mFormatID = kAudioFormatLinearPCM;
audioDescription.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked | kAudioFormatFlagsNativeEndian;
audioDescription.mChannelsPerFrame = 1;
audioDescription.mBytesPerPacket = sizeof(SInt16)*audioDescription.mChannelsPerFrame;
audioDescription.mFramesPerPacket = 1;
audioDescription.mBytesPerFrame = sizeof(SInt16)*audioDescription.mChannelsPerFrame;
audioDescription.mBitsPerChannel = 8 * sizeof(SInt16);
audioDescription.mSampleRate = 44100.0;
return audioDescription;
}
- (void)setupIOUnit
{
try {
// Create a new instance of AURemoteIO
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_RemoteIO;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
AudioComponent comp = AudioComponentFindNext(NULL, &desc);
XThrowIfError(AudioComponentInstanceNew(comp, &_rioUnit), "couldn't create a new instance of AURemoteIO");
// Enable input and output on AURemoteIO
// Input is enabled on the input scope of the input element
// Output is enabled on the output scope of the output element
UInt32 one = 1;
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &one, sizeof(one)), "could not enable input on AURemoteIO");
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &one, sizeof(one)), "could not enable output on AURemoteIO");
// Explicitly set the input and output client formats
// sample rate = 44100, num channels = 1, format = 32 bit floating point
CAStreamBasicDescription ioFormat = CAStreamBasicDescription(44100, 1, CAStreamBasicDescription::kPCMFormatFloat32, false);
// AudioStreamBasicDescription audioFormat = [self getAudioDescription];
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &ioFormat, sizeof(ioFormat)), "couldn't set the input client format on AURemoteIO");
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &ioFormat, sizeof(ioFormat)), "couldn't set the output client format on AURemoteIO");
// Set the MaximumFramesPerSlice property. This property is used to describe to an audio unit the maximum number
// of samples it will be asked to produce on any single given call to AudioUnitRender
UInt32 maxFramesPerSlice = 4096;
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, sizeof(UInt32)), "couldn't set max frames per slice on AURemoteIO");
// Get the property value back from AURemoteIO. We are going to use this value to allocate buffers accordingly
UInt32 propSize = sizeof(UInt32);
XThrowIfError(AudioUnitGetProperty(_rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, &propSize), "couldn't get max frames per slice on AURemoteIO");
_bufferManager = new BufferManager(maxFramesPerSlice);
_dcRejectionFilter = new DCRejectionFilter;
// We need references to certain data in the render callback
// This simple struct is used to hold that information
cd.rioUnit = _rioUnit;
cd.bufferManager = _bufferManager;
cd.dcRejectionFilter = _dcRejectionFilter;
cd.muteAudio = &_muteAudio;
cd.audioChainIsBeingReconstructed = &_audioChainIsBeingReconstructed;
AURenderCallbackStruct renderCallback;
renderCallback.inputProc = performRender;
renderCallback.inputProcRefCon = self;
XThrowIfError(AudioUnitSetProperty(_rioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &renderCallback, sizeof(renderCallback)), "couldn't set render callback on AURemoteIO");
// Initialize the AURemoteIO instance
XThrowIfError(AudioUnitInitialize(_rioUnit), "couldn't initialize AURemoteIO instance");
}
catch (CAXException &e) {
NSLog(#"Error returned from setupIOUnit: %d: %s", (int)e.mError, e.mOperation);
}
catch (...) {
NSLog(#"Unknown error returned from setupIOUnit");
}
return;
}
Full source can be view at: http://pastebin.com/LXLYDEhy

Your code generally looks good from glancing at it, but there's at least one significant issue: instead of allocating space for the data to be copied into the buffers, you are explicitly setting them to NULL. Instead, you should allocate space and then copy it in with AudioUnitRender
Example code:
AudioBufferList *bufferList;
bufferList = (AudioBufferList *)malloc(sizeof(AudioBufferList) + sizeof(AudioBuffer));
bufferList->mNumberBuffers = 1;
bufferList->mBuffers[0].mNumberChannels = 1;
bufferList->mBuffers[0].mDataByteSize = 1024 * 4;
bufferList->mBuffers[0].mData = calloc(1024, 4);
(Note that you may need to adjust the allocation sizes to fit your stream type, size, etc -- the above is just example code, but it addresses your main issue.

Related

How to play live audio on iOS?

I have an IPCamera that requires the use of a custom library for connecting and communication. I have the video all taken care of, but I also want to give the user the option to listen to the audio that is recorded by the camera.
I receive the audio in the form of a byte stream (the audio is PCM u-law).
Since I don't read the data from a file or have an URL I can connect to, I think I would have to use something like AudioUnits or openAL to play my audio.
I tried to implement it with AudioUnits based on the examples I found online and this is what I have so far:
-(void) audioThread
{
char buffer[1024];
int size = 0;
boolean audioConfigured = false;
AudioComponentInstance audioUnit;
while (running) {
getAudioData(buffer,size); //fill buffer with my audio
int16_t* tempChar = (int16_t *)calloc(ret, sizeof(int16_t));
for (int i = 0; i < ret; i++) {
tempChar[i] = MuLaw_Decode(buf[i]);
}
uint8_t *data = NULL;
data = malloc(size);
data = memcpy(data, &tempChar, size);
CMBlockBufferRef blockBuffer = NULL;
OSStatus status = CMBlockBufferCreateWithMemoryBlock(NULL, data,
size,
kCFAllocatorNull, NULL,
0,
size,
0, &blockBuffer);
CMSampleBufferRef sampleBuffer = NULL;
// now I create my samplebuffer from the block buffer
if(status == noErr)
{
const size_t sampleSize = size;
status = CMSampleBufferCreate(kCFAllocatorDefault,
blockBuffer, true, NULL, NULL,
formatDesc, 1, 0, NULL, 1,
&sampleSize, &sampleBuffer);
}
AudioStreamBasicDescription audioBasic;
audioBasic.mBitsPerChannel = 16;
audioBasic.mBytesPerPacket = 2;
audioBasic.mBytesPerFrame = 2;
audioBasic.mChannelsPerFrame = 1;
audioBasic.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
audioBasic.mFormatID = kAudioFormatLinearPCM;
audioBasic.mFramesPerPacket = 1;
audioBasic.mSampleRate = 48000;
audioBasic.mReserved = 0;
if(!audioConfigured)
{
//initialize the circular buffer
if(instance.decodingBuffer == NULL)
instance.decodingBuffer = malloc(sizeof(TPCircularBuffer));
if(!TPCircularBufferInit(instance.decodingBuffer, 1024))
continue;
AudioComponentDescription componentDescription;
componentDescription.componentType = kAudioUnitType_Output;
componentDescription.componentSubType = kAudioUnitSubType_RemoteIO;
componentDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
componentDescription.componentFlags = 0;
componentDescription.componentFlagsMask = 0;
AudioComponent component = AudioComponentFindNext(NULL, &componentDescription);
if(AudioComponentInstanceNew(component, &audioUnit) != noErr) {
NSLog(#"Failed to initialize the AudioComponent");
continue;
}
//enable IO for playback
UInt32 flag = 1;
if(AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &flag, sizeof(flag)) != noErr) {
NSLog(#"Failed to enable IO for playback");
continue;
}
// set the format for the outputstream
if(AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output, 1, &audioBasic, sizeof(audioBasic)) != noErr) {
NSLog(#"Failed to set the format for the outputstream");
continue;
}
// set output callback
AURenderCallbackStruct callbackStruct;
callbackStruct.inputProc = playbackCallback;
callbackStruct.inputProcRefCon = (__bridge void*) self;
if(AudioUnitSetProperty(audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, 0, &callbackStruct, sizeof(callbackStruct))!= noErr) {
NSLog(#"Failed to Set output callback");
continue;
}
// Disable buffer allocation for the recorder (optional - do this if we want to pass in our own)
flag = 0;
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_ShouldAllocateBuffer, kAudioUnitScope_Output, 1, &flag, sizeof(flag));
if(AudioUnitInitialize(audioUnit) != noErr) {
NSLog(#"Failed to initialize audioUnits");
}
if(AudioOutputUnitStart(audioUnit)!= noErr) {
NSLog(#"[thread_ReceiveAudio] Failed to start audio");
}
audioConfigured = true;
}
AudioBufferList bufferList ;
if (sampleBuffer!=NULL) {
CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampleBuffer, NULL, &bufferList, sizeof(bufferList), NULL, NULL, kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment, &blockBuffer);
UInt64 size = CMSampleBufferGetTotalSampleSize(sampleBuffer);
// Put audio into circular buffer
TPCircularBufferProduceBytes(self.decodingBuffer, bufferList.mBuffers[0].mData, size);
//TPCircularBufferCopyAudioBufferList(self.decodingBuffer, &bufferList, NULL, kTPCircularBufferCopyAll, NULL);
CFRelease(sampleBuffer);
CFRelease(blockBuffer);
}
}
//stop playing audio
if(audioConfigured){
if(AudioOutputUnitStop(audioUnit)!= noErr) {
NSLog(#"[thread_ReceiveAudio] Failed to stop audio");
}
else{
//clean up audio
AudioComponentInstanceDispose(audioUnit);
}
}
}
int16_t MuLaw_Decode(int8_t number)
{
const uint16_t MULAW_BIAS = 33;
uint8_t sign = 0, position = 0;
int16_t decoded = 0;
number = ~number;
if (number & 0x80)
{
number &= ~(1 << 7);
sign = -1;
}
position = ((number & 0xF0) >> 4) + 5;
decoded = ((1 << position) | ((number & 0x0F) << (position - 4))
| (1 << (position - 5))) - MULAW_BIAS;
return (sign == 0) ? (decoded) : (-(decoded));
}
static OSStatus playbackCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
int bytesToCopy = ioData->mBuffers[0].mDataByteSize;
SInt16 *targetBuffer = (SInt16*)ioData->mBuffers[0].mData;
int32_t availableBytes;
SInt16 *buffer = TPCircularBufferTail(instance.decodingBuffer, &availableBytes);
int sampleCount = MIN(bytesToCopy, availableBytes);
memcpy(targetBuffer, buffer, MIN(bytesToCopy, availableBytes));
TPCircularBufferConsume(self.decodingBuffer, sampleCount);
return noErr;
}
The code above doesn't produce any errors, but won't play any sound. I though I could set the audio through the bufferList in the recordCallback, but it is never called.
So my question is: How do I play audio from a byte stream on iOS?
I decided to look at the project with fresh eyes. I got rid of most of the code and got it to work now. It is not pretty, but at least it runs for now. For example: I had to set my sample rate to 4000, otherwise it would play to fast and I still have performance issues. Anyway this is what I came up with:
#define BUFFER_SIZE 1024
#define NUM_CHANNELS 2
#define kOutputBus 0
#define kInputBus 1
-(void) main
{
char buf[BUFFER_SIZE];
int size;
runloop: while (self.running) {
getAudioData(&buf, size);
if(!self.configured) {
if(![self activateAudioSession])
continue;
self.configured = true;
}
TPCircularBufferProduceBytes(self.decodingBuffer, buf, size);
}
//stop audiounits
AudioOutputUnitStop(self.audioUnit);
AudioComponentInstanceDispose(self.audioUnit);
if (self.decodingBuffer != NULL) {
TPCircularBufferCleanup(self.decodingBuffer);
}
}
static void audioSessionInterruptionCallback(void *inUserData, UInt32 interruptionState) {
if (interruptionState == kAudioSessionEndInterruption) {
AudioSessionSetActive(YES);
AudioOutputUnitStart(self.audioUnit);
}
if (interruptionState == kAudioSessionBeginInterruption) {
AudioOutputUnitStop(self.audioUnit);
}
}
static OSStatus playbackCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
// Notes: ioData contains buffers (may be more than one!)
// Fill them up as much as you can. Remember to set the size value in each buffer to match how much data is in the buffer.
if (!self.running ) {
return -1;
}
int bytesToCopy = ioData->mBuffers[0].mDataByteSize;
SInt16 *targetBuffer = (SInt16*)ioData->mBuffers[0].mData;
// Pull audio from playthrough buffer
int32_t availableBytes;
if(self.decodingBuffer == NULL || self.decodingBuffer->length < 1) {
NSLog(#"buffer is empty");
return 0;
}
SInt16 *buffer = TPCircularBufferTail(self.decodingBuffer, &availableBytes);
int sampleCount = MIN(bytesToCopy, availableBytes);
memcpy(targetBuffer, buffer, sampleCount);
TPCircularBufferConsume(self.decodingBuffer, sampleCount);
return noErr;
}
- (BOOL) activateAudioSession {
if (!self.activated_) {
OSStatus result;
result = AudioSessionInitialize(NULL,
NULL,
audioSessionInterruptionCallback,
(__bridge void *)(self));
if (kAudioSessionAlreadyInitialized != result)
[self checkError:result message:#"Couldn't initialize audio session"];
[self setupAudio]
self.activated_ = YES;
}
return self.activated_;
}
- (void) setupAudio
{
OSStatus status;
// Describe audio component
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_RemoteIO;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// Get component
AudioComponent inputComponent = AudioComponentFindNext(NULL, &desc);
// Get audio units
AudioComponentInstanceNew(inputComponent, &_audioUnit);
// // Enable IO for recording
// UInt32 flag = 1;
// status = AudioUnitSetProperty(audioUnit,
// kAudioOutputUnitProperty_EnableIO,
// kAudioUnitScope_Input,
// kInputBus,
// &flag,
// sizeof(flag));
// Enable IO for playback
UInt32 flag = 1;
AudioUnitSetProperty(_audioUnit,
kAudioOutputUnitProperty_EnableIO,
kAudioUnitScope_Output,
kOutputBus,
&flag,
sizeof(flag));
// Describe format
AudioStreamBasicDescription format;
format.mSampleRate = 4000;
format.mFormatID = kAudioFormatULaw; //kAudioFormatULaw
format.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;//
format.mBitsPerChannel = 8 * sizeof(char);
format.mChannelsPerFrame = NUM_CHANNELS;
format.mBytesPerFrame = sizeof(char) * NUM_CHANNELS;
format.mFramesPerPacket = 1;
format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket;
format.mReserved = 0;
self.audioFormat = format;
// Apply format
AudioUnitSetProperty(_audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
kInputBus,
&_audioFormat,
sizeof(_audioFormat));
AudioUnitSetProperty(_audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
kOutputBus,
&_audioFormat,
sizeof(_audioFormat));
// // Set input callback
// AURenderCallbackStruct callbackStruct;
// callbackStruct.inputProc = recordingCallback;
// callbackStruct.inputProcRefCon = self;
// status = AudioUnitSetProperty(audioUnit,
// kAudioOutputUnitProperty_SetInputCallback,
// kAudioUnitScope_Global,
// kInputBus,
// &callbackStruct,
// sizeof(callbackStruct));
// checkStatus(status);
// Set output callback
AURenderCallbackStruct callbackStruct;
callbackStruct.inputProc = playbackCallback;
callbackStruct.inputProcRefCon = (__bridge void * _Nullable)(self);
AudioUnitSetProperty(_audioUnit,
kAudioUnitProperty_SetRenderCallback,
kAudioUnitScope_Global,
kOutputBus,
&callbackStruct,
sizeof(callbackStruct));
// Disable buffer allocation for the recorder (optional - do this if we want to pass in our own)
flag = 0;
status = AudioUnitSetProperty(_audioUnit,
kAudioUnitProperty_ShouldAllocateBuffer,
kAudioUnitScope_Output,
kInputBus,
&flag,
sizeof(flag));
//initialize the circular buffer
if(self.decodingBuffer == NULL)
self.decodingBuffer = malloc(sizeof(TPCircularBuffer));
if(!TPCircularBufferInit(self.decodingBuffer, 512*1024))
return NO;
// Initialise
status = AudioUnitInitialize(self.audioUnit);
AudioOutputUnitStart(self.audioUnit);
}
I found most of this by looking through github and from a tasty pixel
If the AVAudioSession is configured to use short buffers, you can use the RemoteIO Audio Unit to play received audio with low additional latency.
Check errors during audio configuration. Some iOS devices only support a 48 kHz sample rate, so you may need to resample your audio PCM data from 8 kHz to another rate.
RemoteIO only supports linear PCM, so you will need to first convert all your incoming 8-bit u-law PCM samples to 16-bit linear PCM format before storing them in a lock-free circular buffer.
You need to call AudioOutputUnitStart to start audio callbacks being called by the OS. Your code should not be calling these callbacks. They will be called by the OS.
AudioUnitRender is used for recording callbacks, not for playing audio. So you don't need to use it. Just fill the AudioBufferList buffers with the requested number of frames in the play callback.
Then you can use the play audio callback to check your circular buffer and pull the requested number of samples, if enough are available. You should not do any memory management (such as a free() call) inside this callback.

Core Audio's render callback does not change output audio [duplicate]

This question already has answers here:
Getting mic input and speaker output using Core Audio
(2 answers)
Closed 7 years ago.
Somehow I cannot change the output or mute it using the render callback when using core audio.
Here is my IO initializing function:
- (void)setupIOUnit
{
// Create a new instance of AURemoteIO
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_RemoteIO;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
AudioComponent comp = AudioComponentFindNext(NULL, &desc);
AudioComponentInstanceNew(comp, &rioUnit);
// Enable input and output on AURemoteIO
// Input is enabled on the input scope of the input element
// Output is enabled on the output scope of the output element
UInt32 one = 1;
AudioUnitSetProperty(rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &one, sizeof(one));
AudioUnitSetProperty(rioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &one, sizeof(one));
AudioStreamBasicDescription audioFormat;
audioFormat.mSampleRate = 44100.00;
audioFormat.mFormatID = kAudioFormatLinearPCM;
audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
audioFormat.mFramesPerPacket = 1;
audioFormat.mChannelsPerFrame = 1;
audioFormat.mBitsPerChannel = 16;
audioFormat.mBytesPerPacket = 2;
audioFormat.mBytesPerFrame = 2;
AudioUnitSetProperty(rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &audioFormat, sizeof(audioFormat));
AudioUnitSetProperty(rioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &audioFormat, sizeof(audioFormat));
// Set the MaximumFramesPerSlice property. This property is used to describe to an audio unit the maximum number
// of samples it will be asked to produce on any single given call to AudioUnitRender
UInt32 maxFramesPerSlice = 4096;
AudioUnitSetProperty(rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, sizeof(UInt32));
// Get the property value back from AURemoteIO. We are going to use this value to allocate buffers accordingly
UInt32 propSize = sizeof(UInt32);
AudioUnitGetProperty(rioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, &maxFramesPerSlice, &propSize);
// Set the render callback on AURemoteIO
AURenderCallbackStruct renderCallback;
renderCallback.inputProc = performRender;
renderCallback.inputProcRefCon = NULL;
AudioUnitSetProperty(rioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &renderCallback, sizeof(renderCallback));
NSLog(#"render set now");
// Initialize the AURemoteIO instance
AudioUnitInitialize(rioUnit);
[self startIOUnit];
return;
}
Here is my function for rendering:
// Render callback function
static OSStatus performRender (void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData)
{
OSStatus err = noErr;
err = AudioUnitRender(rioUnit, ioActionFlags, inTimeStamp, 1, inNumberFrames, ioData);
if (ioData->mBuffers[0].mDataByteSize >= 12) {
NSData *myAudioData = [NSData dataWithBytes: ioData->mBuffers[0].mData length:12];
NSLog(#"aa playback's first 12 bytes: %#", myAudioData);
}
for (UInt32 i=0; i<ioData->mNumberBuffers; ++i) {
memset(ioData->mBuffers[i].mData, 0, ioData->mBuffers[i].mDataByteSize);
}
return err;
}
This does not mute the output sound and I can still hear things from my streaming App. What are the possible scenarios in which this could happen? How come my sound is not muted?
Any insight would be helpful
Could you clarify what you mean when you say "I can still hear things from my streaming App"? Are you referring to sound coming in through the microphone, or do you have something else going on in the app?
FWIW: you're clearly adapting Apple's aurioTouch sample, and if I drop your setupIOUnit method and render callback into that project and run it, muting works fine - i.e., you don't appear to be breaking anything with the code you've posted here. That suggests the problem lies somewhere else in your code.

core audio offline rendering GenericOutput

Anybody successfully done offline rendering using core-Audio.?
I had to mix two audio files and apply reverb(used 2 AudioFilePlayer,MultiChannelMixer,Reverb2 and RemoteIO).
Got it working. and i could save it while its previewing(on renderCallBack of RemoteIO).
I need to save it without playing it (offline).
Thanks in advance.
Offline rendering Worked for me using GenericOutput AudioUnit.
I am sharing the working code here.
core-audio framework seems a little though. But small-small things in it like ASBD, parameters ...etc are making these issues. try hard it will work. Don't give-up :-). core-audio is very powerful and useful while dealing with low-level audio. Thats what I learned from these last weeks. Enjoy :-D ....
Declare these in .h
//AUGraph
AUGraph mGraph;
//Audio Unit References
AudioUnit mFilePlayer;
AudioUnit mFilePlayer2;
AudioUnit mReverb;
AudioUnit mTone;
AudioUnit mMixer;
AudioUnit mGIO;
//Audio File Location
AudioFileID inputFile;
AudioFileID inputFile2;
//Audio file refereces for saving
ExtAudioFileRef extAudioFile;
//Standard sample rate
Float64 graphSampleRate;
AudioStreamBasicDescription stereoStreamFormat864;
Float64 MaxSampleTime;
//in .m class
- (id) init
{
self = [super init];
graphSampleRate = 44100.0;
MaxSampleTime = 0.0;
UInt32 category = kAudioSessionCategory_MediaPlayback;
CheckError(AudioSessionSetProperty(kAudioSessionProperty_AudioCategory,
sizeof(category),
&category),
"Couldn't set category on audio session");
[self initializeAUGraph];
return self;
}
//ASBD setup
- (void) setupStereoStream864 {
// The AudioUnitSampleType data type is the recommended type for sample data in audio
// units. This obtains the byte size of the type for use in filling in the ASBD.
size_t bytesPerSample = sizeof (AudioUnitSampleType);
// Fill the application audio format struct's fields to define a linear PCM,
// stereo, noninterleaved stream at the hardware sample rate.
stereoStreamFormat864.mFormatID = kAudioFormatLinearPCM;
stereoStreamFormat864.mFormatFlags = kAudioFormatFlagsAudioUnitCanonical;
stereoStreamFormat864.mBytesPerPacket = bytesPerSample;
stereoStreamFormat864.mFramesPerPacket = 1;
stereoStreamFormat864.mBytesPerFrame = bytesPerSample;
stereoStreamFormat864.mChannelsPerFrame = 2; // 2 indicates stereo
stereoStreamFormat864.mBitsPerChannel = 8 * bytesPerSample;
stereoStreamFormat864.mSampleRate = graphSampleRate;
}
//AUGraph setup
- (void)initializeAUGraph
{
[self setupStereoStream864];
// Setup the AUGraph, add AUNodes, and make connections
// create a new AUGraph
CheckError(NewAUGraph(&mGraph),"Couldn't create new graph");
// AUNodes represent AudioUnits on the AUGraph and provide an
// easy means for connecting audioUnits together.
AUNode filePlayerNode;
AUNode filePlayerNode2;
AUNode mixerNode;
AUNode reverbNode;
AUNode toneNode;
AUNode gOutputNode;
// file player component
AudioComponentDescription filePlayer_desc;
filePlayer_desc.componentType = kAudioUnitType_Generator;
filePlayer_desc.componentSubType = kAudioUnitSubType_AudioFilePlayer;
filePlayer_desc.componentFlags = 0;
filePlayer_desc.componentFlagsMask = 0;
filePlayer_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// file player component2
AudioComponentDescription filePlayer2_desc;
filePlayer2_desc.componentType = kAudioUnitType_Generator;
filePlayer2_desc.componentSubType = kAudioUnitSubType_AudioFilePlayer;
filePlayer2_desc.componentFlags = 0;
filePlayer2_desc.componentFlagsMask = 0;
filePlayer2_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// Create AudioComponentDescriptions for the AUs we want in the graph
// mixer component
AudioComponentDescription mixer_desc;
mixer_desc.componentType = kAudioUnitType_Mixer;
mixer_desc.componentSubType = kAudioUnitSubType_MultiChannelMixer;
mixer_desc.componentFlags = 0;
mixer_desc.componentFlagsMask = 0;
mixer_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// Create AudioComponentDescriptions for the AUs we want in the graph
// Reverb component
AudioComponentDescription reverb_desc;
reverb_desc.componentType = kAudioUnitType_Effect;
reverb_desc.componentSubType = kAudioUnitSubType_Reverb2;
reverb_desc.componentFlags = 0;
reverb_desc.componentFlagsMask = 0;
reverb_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
//tone component
AudioComponentDescription tone_desc;
tone_desc.componentType = kAudioUnitType_FormatConverter;
//tone_desc.componentSubType = kAudioUnitSubType_NewTimePitch;
tone_desc.componentSubType = kAudioUnitSubType_Varispeed;
tone_desc.componentFlags = 0;
tone_desc.componentFlagsMask = 0;
tone_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
AudioComponentDescription gOutput_desc;
gOutput_desc.componentType = kAudioUnitType_Output;
gOutput_desc.componentSubType = kAudioUnitSubType_GenericOutput;
gOutput_desc.componentFlags = 0;
gOutput_desc.componentFlagsMask = 0;
gOutput_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
//Add nodes to graph
// Add nodes to the graph to hold our AudioUnits,
// You pass in a reference to the AudioComponentDescription
// and get back an AudioUnit
AUGraphAddNode(mGraph, &filePlayer_desc, &filePlayerNode );
AUGraphAddNode(mGraph, &filePlayer2_desc, &filePlayerNode2 );
AUGraphAddNode(mGraph, &mixer_desc, &mixerNode );
AUGraphAddNode(mGraph, &reverb_desc, &reverbNode );
AUGraphAddNode(mGraph, &tone_desc, &toneNode );
AUGraphAddNode(mGraph, &gOutput_desc, &gOutputNode);
//Open the graph early, initialize late
// open the graph AudioUnits are open but not initialized (no resource allocation occurs here)
CheckError(AUGraphOpen(mGraph),"Couldn't Open the graph");
//Reference to Nodes
// get the reference to the AudioUnit object for the file player graph node
AUGraphNodeInfo(mGraph, filePlayerNode, NULL, &mFilePlayer);
AUGraphNodeInfo(mGraph, filePlayerNode2, NULL, &mFilePlayer2);
AUGraphNodeInfo(mGraph, reverbNode, NULL, &mReverb);
AUGraphNodeInfo(mGraph, toneNode, NULL, &mTone);
AUGraphNodeInfo(mGraph, mixerNode, NULL, &mMixer);
AUGraphNodeInfo(mGraph, gOutputNode, NULL, &mGIO);
AUGraphConnectNodeInput(mGraph, filePlayerNode, 0, reverbNode, 0);
AUGraphConnectNodeInput(mGraph, reverbNode, 0, toneNode, 0);
AUGraphConnectNodeInput(mGraph, toneNode, 0, mixerNode,0);
AUGraphConnectNodeInput(mGraph, filePlayerNode2, 0, mixerNode, 1);
AUGraphConnectNodeInput(mGraph, mixerNode, 0, gOutputNode, 0);
UInt32 busCount = 2; // bus count for mixer unit input
//Setup mixer unit bus count
CheckError(AudioUnitSetProperty (
mMixer,
kAudioUnitProperty_ElementCount,
kAudioUnitScope_Input,
0,
&busCount,
sizeof (busCount)
),
"Couldn't set mixer unit's bus count");
//Enable metering mode to view levels input and output levels of mixer
UInt32 onValue = 1;
CheckError(AudioUnitSetProperty(mMixer,
kAudioUnitProperty_MeteringMode,
kAudioUnitScope_Input,
0,
&onValue,
sizeof(onValue)),
"error");
// Increase the maximum frames per slice allows the mixer unit to accommodate the
// larger slice size used when the screen is locked.
UInt32 maximumFramesPerSlice = 4096;
CheckError(AudioUnitSetProperty (
mMixer,
kAudioUnitProperty_MaximumFramesPerSlice,
kAudioUnitScope_Global,
0,
&maximumFramesPerSlice,
sizeof (maximumFramesPerSlice)
),
"Couldn't set mixer units maximum framers per slice");
// set the audio data format of tone Unit
AudioUnitSetProperty(mTone,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Global,
0,
&stereoStreamFormat864,
sizeof(AudioStreamBasicDescription));
// set the audio data format of reverb Unit
AudioUnitSetProperty(mReverb,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Global,
0,
&stereoStreamFormat864,
sizeof(AudioStreamBasicDescription));
// set initial reverb
AudioUnitParameterValue reverbTime = 2.5;
AudioUnitSetParameter(mReverb, 4, kAudioUnitScope_Global, 0, reverbTime, 0);
AudioUnitSetParameter(mReverb, 5, kAudioUnitScope_Global, 0, reverbTime, 0);
AudioUnitSetParameter(mReverb, 0, kAudioUnitScope_Global, 0, 0, 0);
AudioStreamBasicDescription auEffectStreamFormat;
UInt32 asbdSize = sizeof (auEffectStreamFormat);
memset (&auEffectStreamFormat, 0, sizeof (auEffectStreamFormat ));
// get the audio data format from reverb
CheckError(AudioUnitGetProperty(mReverb,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
0,
&auEffectStreamFormat,
&asbdSize),
"Couldn't get aueffectunit ASBD");
auEffectStreamFormat.mSampleRate = graphSampleRate;
// set the audio data format of mixer Unit
CheckError(AudioUnitSetProperty(mMixer,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
0,
&auEffectStreamFormat, sizeof(auEffectStreamFormat)),
"Couldn't set ASBD on mixer output");
CheckError(AUGraphInitialize(mGraph),"Couldn't Initialize the graph");
[self setUpAUFilePlayer];
[self setUpAUFilePlayer2];
}
//Audio file playback setup here i am setting the voice file
-(OSStatus) setUpAUFilePlayer{
NSString *songPath = [[NSBundle mainBundle] pathForResource: #"testVoice" ofType:#".m4a"];
CFURLRef songURL = ( CFURLRef) [NSURL fileURLWithPath:songPath];
// open the input audio file
CheckError(AudioFileOpenURL(songURL, kAudioFileReadPermission, 0, &inputFile),
"setUpAUFilePlayer AudioFileOpenURL failed");
AudioStreamBasicDescription fileASBD;
// get the audio data format from the file
UInt32 propSize = sizeof(fileASBD);
CheckError(AudioFileGetProperty(inputFile, kAudioFilePropertyDataFormat,
&propSize, &fileASBD),
"setUpAUFilePlayer couldn't get file's data format");
// tell the file player unit to load the file we want to play
CheckError(AudioUnitSetProperty(mFilePlayer, kAudioUnitProperty_ScheduledFileIDs,
kAudioUnitScope_Global, 0, &inputFile, sizeof(inputFile)),
"setUpAUFilePlayer AudioUnitSetProperty[kAudioUnitProperty_ScheduledFileIDs] failed");
UInt64 nPackets;
UInt32 propsize = sizeof(nPackets);
CheckError(AudioFileGetProperty(inputFile, kAudioFilePropertyAudioDataPacketCount,
&propsize, &nPackets),
"setUpAUFilePlayer AudioFileGetProperty[kAudioFilePropertyAudioDataPacketCount] failed");
// tell the file player AU to play the entire file
ScheduledAudioFileRegion rgn;
memset (&rgn.mTimeStamp, 0, sizeof(rgn.mTimeStamp));
rgn.mTimeStamp.mFlags = kAudioTimeStampSampleTimeValid;
rgn.mTimeStamp.mSampleTime = 0;
rgn.mCompletionProc = NULL;
rgn.mCompletionProcUserData = NULL;
rgn.mAudioFile = inputFile;
rgn.mLoopCount = -1;
rgn.mStartFrame = 0;
rgn.mFramesToPlay = nPackets * fileASBD.mFramesPerPacket;
if (MaxSampleTime < rgn.mFramesToPlay)
{
MaxSampleTime = rgn.mFramesToPlay;
}
CheckError(AudioUnitSetProperty(mFilePlayer, kAudioUnitProperty_ScheduledFileRegion,
kAudioUnitScope_Global, 0,&rgn, sizeof(rgn)),
"setUpAUFilePlayer1 AudioUnitSetProperty[kAudioUnitProperty_ScheduledFileRegion] failed");
// prime the file player AU with default values
UInt32 defaultVal = 0;
CheckError(AudioUnitSetProperty(mFilePlayer, kAudioUnitProperty_ScheduledFilePrime,
kAudioUnitScope_Global, 0, &defaultVal, sizeof(defaultVal)),
"setUpAUFilePlayer AudioUnitSetProperty[kAudioUnitProperty_ScheduledFilePrime] failed");
// tell the file player AU when to start playing (-1 sample time means next render cycle)
AudioTimeStamp startTime;
memset (&startTime, 0, sizeof(startTime));
startTime.mFlags = kAudioTimeStampSampleTimeValid;
startTime.mSampleTime = -1;
CheckError(AudioUnitSetProperty(mFilePlayer, kAudioUnitProperty_ScheduleStartTimeStamp,
kAudioUnitScope_Global, 0, &startTime, sizeof(startTime)),
"setUpAUFilePlayer AudioUnitSetProperty[kAudioUnitProperty_ScheduleStartTimeStamp]");
return noErr;
}
//Audio file playback setup here i am setting the BGMusic file
-(OSStatus) setUpAUFilePlayer2{
NSString *songPath = [[NSBundle mainBundle] pathForResource: #"BGmusic" ofType:#".mp3"];
CFURLRef songURL = ( CFURLRef) [NSURL fileURLWithPath:songPath];
// open the input audio file
CheckError(AudioFileOpenURL(songURL, kAudioFileReadPermission, 0, &inputFile2),
"setUpAUFilePlayer2 AudioFileOpenURL failed");
AudioStreamBasicDescription fileASBD;
// get the audio data format from the file
UInt32 propSize = sizeof(fileASBD);
CheckError(AudioFileGetProperty(inputFile2, kAudioFilePropertyDataFormat,
&propSize, &fileASBD),
"setUpAUFilePlayer2 couldn't get file's data format");
// tell the file player unit to load the file we want to play
CheckError(AudioUnitSetProperty(mFilePlayer2, kAudioUnitProperty_ScheduledFileIDs,
kAudioUnitScope_Global, 0, &inputFile2, sizeof(inputFile2)),
"setUpAUFilePlayer2 AudioUnitSetProperty[kAudioUnitProperty_ScheduledFileIDs] failed");
UInt64 nPackets;
UInt32 propsize = sizeof(nPackets);
CheckError(AudioFileGetProperty(inputFile2, kAudioFilePropertyAudioDataPacketCount,
&propsize, &nPackets),
"setUpAUFilePlayer2 AudioFileGetProperty[kAudioFilePropertyAudioDataPacketCount] failed");
// tell the file player AU to play the entire file
ScheduledAudioFileRegion rgn;
memset (&rgn.mTimeStamp, 0, sizeof(rgn.mTimeStamp));
rgn.mTimeStamp.mFlags = kAudioTimeStampSampleTimeValid;
rgn.mTimeStamp.mSampleTime = 0;
rgn.mCompletionProc = NULL;
rgn.mCompletionProcUserData = NULL;
rgn.mAudioFile = inputFile2;
rgn.mLoopCount = -1;
rgn.mStartFrame = 0;
rgn.mFramesToPlay = nPackets * fileASBD.mFramesPerPacket;
if (MaxSampleTime < rgn.mFramesToPlay)
{
MaxSampleTime = rgn.mFramesToPlay;
}
CheckError(AudioUnitSetProperty(mFilePlayer2, kAudioUnitProperty_ScheduledFileRegion,
kAudioUnitScope_Global, 0,&rgn, sizeof(rgn)),
"setUpAUFilePlayer2 AudioUnitSetProperty[kAudioUnitProperty_ScheduledFileRegion] failed");
// prime the file player AU with default values
UInt32 defaultVal = 0;
CheckError(AudioUnitSetProperty(mFilePlayer2, kAudioUnitProperty_ScheduledFilePrime,
kAudioUnitScope_Global, 0, &defaultVal, sizeof(defaultVal)),
"setUpAUFilePlayer2 AudioUnitSetProperty[kAudioUnitProperty_ScheduledFilePrime] failed");
// tell the file player AU when to start playing (-1 sample time means next render cycle)
AudioTimeStamp startTime;
memset (&startTime, 0, sizeof(startTime));
startTime.mFlags = kAudioTimeStampSampleTimeValid;
startTime.mSampleTime = -1;
CheckError(AudioUnitSetProperty(mFilePlayer2, kAudioUnitProperty_ScheduleStartTimeStamp,
kAudioUnitScope_Global, 0, &startTime, sizeof(startTime)),
"setUpAUFilePlayer2 AudioUnitSetProperty[kAudioUnitProperty_ScheduleStartTimeStamp]");
return noErr;
}
//Start Saving File
- (void)startRecordingAAC{
AudioStreamBasicDescription destinationFormat;
memset(&destinationFormat, 0, sizeof(destinationFormat));
destinationFormat.mChannelsPerFrame = 2;
destinationFormat.mFormatID = kAudioFormatMPEG4AAC;
UInt32 size = sizeof(destinationFormat);
OSStatus result = AudioFormatGetProperty(kAudioFormatProperty_FormatInfo, 0, NULL, &size, &destinationFormat);
if(result) printf("AudioFormatGetProperty %ld \n", result);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *destinationFilePath = [[NSString alloc] initWithFormat: #"%#/output.m4a", documentsDirectory];
CFURLRef destinationURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault,
(CFStringRef)destinationFilePath,
kCFURLPOSIXPathStyle,
false);
[destinationFilePath release];
// specify codec Saving the output in .m4a format
result = ExtAudioFileCreateWithURL(destinationURL,
kAudioFileM4AType,
&destinationFormat,
NULL,
kAudioFileFlags_EraseFile,
&extAudioFile);
if(result) printf("ExtAudioFileCreateWithURL %ld \n", result);
CFRelease(destinationURL);
// This is a very important part and easiest way to set the ASBD for the File with correct format.
AudioStreamBasicDescription clientFormat;
UInt32 fSize = sizeof (clientFormat);
memset(&clientFormat, 0, sizeof(clientFormat));
// get the audio data format from the Output Unit
CheckError(AudioUnitGetProperty(mGIO,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
0,
&clientFormat,
&fSize),"AudioUnitGetProperty on failed");
// set the audio data format of mixer Unit
CheckError(ExtAudioFileSetProperty(extAudioFile,
kExtAudioFileProperty_ClientDataFormat,
sizeof(clientFormat),
&clientFormat),
"ExtAudioFileSetProperty kExtAudioFileProperty_ClientDataFormat failed");
// specify codec
UInt32 codec = kAppleHardwareAudioCodecManufacturer;
CheckError(ExtAudioFileSetProperty(extAudioFile,
kExtAudioFileProperty_CodecManufacturer,
sizeof(codec),
&codec),"ExtAudioFileSetProperty on extAudioFile Faild");
CheckError(ExtAudioFileWriteAsync(extAudioFile, 0, NULL),"ExtAudioFileWriteAsync Failed");
[self pullGenericOutput];
}
// Manual Feeding and getting data/Buffer from the GenericOutput Node.
-(void)pullGenericOutput{
AudioUnitRenderActionFlags flags = 0;
AudioTimeStamp inTimeStamp;
memset(&inTimeStamp, 0, sizeof(AudioTimeStamp));
inTimeStamp.mFlags = kAudioTimeStampSampleTimeValid;
UInt32 busNumber = 0;
UInt32 numberFrames = 512;
inTimeStamp.mSampleTime = 0;
int channelCount = 2;
NSLog(#"Final numberFrames :%li",numberFrames);
int totFrms = MaxSampleTime;
while (totFrms > 0)
{
if (totFrms < numberFrames)
{
numberFrames = totFrms;
NSLog(#"Final numberFrames :%li",numberFrames);
}
else
{
totFrms -= numberFrames;
}
AudioBufferList *bufferList = (AudioBufferList*)malloc(sizeof(AudioBufferList)+sizeof(AudioBuffer)*(channelCount-1));
bufferList->mNumberBuffers = channelCount;
for (int j=0; j<channelCount; j++)
{
AudioBuffer buffer = {0};
buffer.mNumberChannels = 1;
buffer.mDataByteSize = numberFrames*sizeof(AudioUnitSampleType);
buffer.mData = calloc(numberFrames, sizeof(AudioUnitSampleType));
bufferList->mBuffers[j] = buffer;
}
CheckError(AudioUnitRender(mGIO,
&flags,
&inTimeStamp,
busNumber,
numberFrames,
bufferList),
"AudioUnitRender mGIO");
CheckError(ExtAudioFileWrite(extAudioFile, numberFrames, bufferList),("extaudiofilewrite fail"));
}
[self FilesSavingCompleted];
}
//FilesSavingCompleted
-(void)FilesSavingCompleted{
OSStatus status = ExtAudioFileDispose(extAudioFile);
printf("OSStatus(ExtAudioFileDispose): %ld\n", status);
}
One way to do offline rendering is to remove the RemoteIO unit and explicitly call AudioUnitRender on the right-most unit in your graph (either the mixer or the reverb unit depending on your topology). By doing this in a loop until you exhaust the samples from both of your source files, and writing the resulting sample buffers with Extended Audio File Services, you can create a compressed audio file of the mixdown. You'll want to do this on a background thread to keep the UI responsive, but I've used this technique before with some success.
Above code is working on iOS7 device but not working on iOS8 device and on all simulators.
I had replaced the following code segment
UInt32 category = kAudioSessionCategory_MediaPlayback;
CheckError(AudioSessionSetProperty(kAudioSessionProperty_AudioCategory,
sizeof(category),
&category),
"Couldn't set category on audio session");
with the following code. Because AudioSessionSetProperty is deprecated so I had replaced following code.
AVAudioSession *session = [AVAudioSession sharedInstance];
NSError *setCategoryError = nil;
if (![session setCategory:AVAudioSessionCategoryPlayback
withOptions:AVAudioSessionCategoryOptionMixWithOthers
error:&setCategoryError]) {
// handle error
}
There must be some update for iOS 8. which can be in above code or in some where else.
I followed Abdusha's approach but my output file had no audio plus the size was very small as compared to the input. After looking into it, a fix I made was in "pullGenericOutput" function. After AudioUnitRender call:
AudioUnitRender(genericOutputUnit,
&flags,
&inTimeStamp,
busNumber,
numberFrames,
bufferList);
inTimeStamp.mSampleTime++; //Updated
increment the timeStamp by 1. After doing this, the output file was perfect with effects working. Thanks. Your answer helped a lot.

OSStatus error -50 (paramErr) on AudioUnitRender call on device

I'm writing an iOS app that captures audio from the microphone, filters it with a high-pass filter, and plays it back through the speakers.
I'm getting a -50 OSStatus error when I call AudioUnitRender on the render callback function when I run it on an iPhone 4S, but it runs fine on the simulator.
I'm using an AUGraph, which has a RemoteIO unit, a HighPassFilter effect unit, and an AUConverter unit to make the ASBDs between the HPF and the output match. The converter AudioUnit instance is called converterUnit.
Here's the code.
static OSStatus renderInput(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber, UInt32 inNumberFrames, AudioBufferList *ioData)
{
AudioController *THIS = (AudioController*)inRefCon;
AudioBuffer buffer;
AudioStreamBasicDescription converterOutputASBD;
UInt32 converterOutputASBDSize = sizeof(converterOutputASBD);
AudioUnitGetProperty([THIS converterUnit], kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &converterOutputASBD, &converterOutputASBDSize);
buffer.mDataByteSize = inNumberFrames * converterOutputASBD.mBytesPerFrame;
buffer.mNumberChannels = converterOutputASBD.mChannelsPerFrame;
buffer.mData = malloc(buffer.mDataByteSize);
AudioBufferList bufferList;
bufferList.mNumberBuffers = 1;
bufferList.mBuffers[0] = buffer;
OSStatus result = AudioUnitRender([THIS converterUnit], ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, &bufferList);
...
}
I think -50 error means one of the parameters is wrong. The only parameters that can be wrong are [THIS converterUnit] and &bufferList, given that all the rest are handed to me as arguments. I've checked the converterUnit instance and it is correctly allocated and initialized (what's more, if that was the problem, it wouldn't run on the simulator either). The only parameter left to check is the bufferList. What I could make out so far from debugging is that both the RemoteIO's output element's input ASBD, and the inNumberFrames are different in the phone and on the simulator. But still, I think that to me that doesn't change things, given that I create and allocate memory for the AudioBuffer buffer based on an ASBD resulting from a AudioUnitGetProperty([THIS ioUnit], kAudioUnitProperty_StreamFormat, ...) call.
Any help will be much appreciated, I'm kind of running desperate here..
You guys rock.
Cheers.
UPDATE:
Here's the audio controller class' definition:
#interface AudioController : NSObject
{
AUGraph mGraph;
AudioUnit mEffects;
AudioUnit ioUnit;
AudioUnit converterUnit;
}
#property (readonly, nonatomic) AudioUnit mEffects;
#property (readonly, nonatomic) AudioUnit ioUnit;
#property (readonly, nonatomic) AudioUnit converterUnit;
#property (nonatomic) float* volumenPromedio;
-(void)initializeAUGraph;
-(void)startAUGraph;
-(void)stopAUGraph;
#end
, and here's the initialization code for the AUGraph (defined in AudioController.mm):
- (void)initializeAUGraph
{
NSError *audioSessionError = nil;
AVAudioSession *mySession = [AVAudioSession sharedInstance];
[mySession setPreferredHardwareSampleRate: kGraphSampleRate
error: &audioSessionError];
[mySession setCategory: AVAudioSessionCategoryPlayAndRecord
error: &audioSessionError];
[mySession setActive: YES error: &audioSessionError];
OSStatus result = noErr;
// create a new AUGraph
result = NewAUGraph(&mGraph);
AUNode outputNode;
AUNode effectsNode;
AUNode converterNode;
// effects component
AudioComponentDescription effects_desc;
effects_desc.componentType = kAudioUnitType_Effect;
effects_desc.componentSubType = kAudioUnitSubType_HighPassFilter;
effects_desc.componentFlags = 0;
effects_desc.componentFlagsMask = 0;
effects_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// output component
AudioComponentDescription output_desc;
output_desc.componentType = kAudioUnitType_Output;
output_desc.componentSubType = kAudioUnitSubType_RemoteIO;
output_desc.componentFlags = 0;
output_desc.componentFlagsMask = 0;
output_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// stream format converter component
AudioComponentDescription converter_desc;
converter_desc.componentType = kAudioUnitType_FormatConverter;
converter_desc.componentSubType = kAudioUnitSubType_AUConverter;
converter_desc.componentFlags = 0;
converter_desc.componentFlagsMask = 0;
converter_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// Add nodes to the graph
result = AUGraphAddNode(mGraph, &output_desc, &outputNode);
[self hasError:result:__FILE__:__LINE__];
result = AUGraphAddNode(mGraph, &effects_desc, &effectsNode);
[self hasError:result:__FILE__:__LINE__];
result = AUGraphAddNode(mGraph, &converter_desc, &converterNode);
// manage connections in the graph
// Connect the io unit node's input element's output to the effectsNode input
result = AUGraphConnectNodeInput(mGraph, outputNode, 1, effectsNode, 0);
// Connect the effects node's output to the converter node's input
result = AUGraphConnectNodeInput(mGraph, effectsNode, 0, converterNode, 0);
// open the graph
result = AUGraphOpen(mGraph);
// Get references to the audio units
result = AUGraphNodeInfo(mGraph, effectsNode, NULL, &mEffects);
result = AUGraphNodeInfo(mGraph, outputNode, NULL, &ioUnit);
result = AUGraphNodeInfo(mGraph, converterNode, NULL, &converterUnit);
// Enable input on remote io unit
UInt32 flag = 1;
result = AudioUnitSetProperty(ioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &flag, sizeof(flag));
// Setup render callback struct
AURenderCallbackStruct renderCallbackStruct;
renderCallbackStruct.inputProc = &renderInput;
renderCallbackStruct.inputProcRefCon = self;
result = AUGraphSetNodeInputCallback(mGraph, outputNode, 0, &renderCallbackStruct);
// Get fx unit's input current stream format...
AudioStreamBasicDescription fxInputASBD;
UInt32 sizeOfASBD = sizeof(AudioStreamBasicDescription);
result = AudioUnitGetProperty(mEffects, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &fxInputASBD, &sizeOfASBD);
// ...and set it on the io unit's input scope's output
result = AudioUnitSetProperty(ioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
1,
&fxInputASBD,
sizeof(fxInputASBD));
// Set fx unit's output sample rate, just in case
Float64 sampleRate = 44100.0;
result = AudioUnitSetProperty(mEffects,
kAudioUnitProperty_SampleRate,
kAudioUnitScope_Output,
0,
&sampleRate,
sizeof(sampleRate));
AudioStreamBasicDescription fxOutputASBD;
// get fx audio unit's output ASBD...
result = AudioUnitGetProperty(mEffects, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &fxOutputASBD, &sizeOfASBD);
// ...and set it to the converter audio unit's input
result = AudioUnitSetProperty(converterUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &fxOutputASBD, sizeof(fxOutputASBD));
AudioStreamBasicDescription ioUnitsOutputElementInputASBD;
// now get io audio unit's output element's input ASBD...
result = AudioUnitGetProperty(ioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &ioUnitsOutputElementInputASBD, &sizeOfASBD);
// ...set the sample rate...
ioUnitsOutputElementInputASBD.mSampleRate = 44100.0;
// ...and set it to the converter audio unit's output
result = AudioUnitSetProperty(converterUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &ioUnitsOutputElementInputASBD, sizeof(ioUnitsOutputElementInputASBD));
// initialize graph
result = AUGraphInitialize(mGraph);
}
The reason I make the connection between the converter's output and the remote io unit's output element's input with a render callback function (rather than with the AUGraphConnectNodeInput method) is because I need to make some calculations on the samples right after they've been processed by the high-pass filter. The render callback gives me the opportunity to look into the samples buffer right after the AudioUnitRender call, and do said calculations there.
UPDATE 2:
By debugging, I found differences in the Remote IO output bus' input ASBD on the device and on the simulator. It shouldn't make a difference (I allocate and initialize the AudioBufferList based on data coming from a previous AudioUnitGetProperty([THIS ioUnit], kAudioUnitProperty_StreamFormat, ...) call), but it's the only thing I can see different in the device and the simulator.
Here's the Remote IO output bus' input ASBD on the device:
Float64 mSampleRate 44100
UInt32 mFormatID 1819304813
UInt32 mFormatFlags 41
UInt32 mBytesPerPacket 4
UInt32 mFramesPerPacket 1
UInt32 mBytesPerFrame 4
UInt32 mChannelsPerFrame 2
UInt32 mBitsPerChannel 32
UInt32 mReserved 0
, and here it is on the simulator:
Float64 mSampleRate 44100
UInt32 mFormatID 1819304813
UInt32 mFormatFlags 12
UInt32 mBytesPerPacket 4
UInt32 mFramesPerPacket 1
UInt32 mBytesPerFrame 4
UInt32 mChannelsPerFrame 2
UInt32 mBitsPerChannel 16
UInt32 mReserved 0

Core Audio memory issues

My Audio Unit analysis project is having some memory issues, whereby each time an Audio Unit is rendered (or somewhere around that) it is allocating a bunch of memory which isn't being released, causing memory usage to swell and the app to eventually crash.
In instruments, I notice the following string of 32 byte mallocs occurring repeatedly, and they remain live:
BufferedAudioConverter::AllocateBuffers() x6
BufferedInputAudioConverter:BufferedInputAudioConverter(StreamDescPair const&) x 3
Any ideas where the problem might lie? When is that memory allocated in the process and how can it safely be released?
Many thanks.
The code was based on some non-Apple sample code, PitchDetector from sleepyleaf.com
Some code extracts where the problem might lie..... Please let me know if more code is needed.
renderErr = AudioUnitRender(rioUnit, ioActionFlags,
inTimeStamp, bus1, inNumberFrames, THIS->bufferList); //128 inNumberFrames
if (renderErr < 0) {
return renderErr;
}
// Fill the buffer with our sampled data. If we fill our buffer, run the
// fft.
int read = bufferCapacity - index;
if (read > inNumberFrames) {
memcpy((SInt16 *)dataBuffer + index, THIS->bufferList->mBuffers[0].mData, inNumberFrames*sizeof(SInt16));
THIS->index += inNumberFrames;
} else { DO ANALYSIS
memset(outputBuffer, 0, n*sizeof(SInt16));
- (void)createAUProcessingGraph {
OSStatus err;
// 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 ioUnitDescription;
ioUnitDescription.componentType = kAudioUnitType_Output;
ioUnitDescription.componentSubType = kAudioUnitSubType_RemoteIO;
ioUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
ioUnitDescription.componentFlags = 0;
enter code here
ioUnitDescription.componentFlagsMask = 0;
// Declare and instantiate an audio processing graph
NewAUGraph(&processingGraph);
// Add an audio unit node to the graph, then instantiate the audio unit.
/*
An AUNode is an opaque type that represents an audio unit in the context
of an audio processing graph. You receive a reference to the new audio unit
instance, in the ioUnit parameter, on output of the AUGraphNodeInfo
function call.
*/
AUNode ioNode;
AUGraphAddNode(processingGraph, &ioUnitDescription, &ioNode);
AUGraphOpen(processingGraph); // indirectly performs audio unit instantiation
// Obtain a reference to the newly-instantiated I/O unit. Each Audio Unit
// requires its own configuration.
AUGraphNodeInfo(processingGraph, ioNode, NULL, &ioUnit);
// Initialize below.
AURenderCallbackStruct callbackStruct = {0};
UInt32 enableInput;
UInt32 enableOutput;
// Enable input and disable output.
enableInput = 1; enableOutput = 0;
callbackStruct.inputProc = RenderFFTCallback;
callbackStruct.inputProcRefCon = (__bridge void*)self;
err = AudioUnitSetProperty(ioUnit, kAudioOutputUnitProperty_EnableIO,
kAudioUnitScope_Input,
kInputBus, &enableInput, sizeof(enableInput));
err = AudioUnitSetProperty(ioUnit, kAudioOutputUnitProperty_EnableIO,
kAudioUnitScope_Output,
kOutputBus, &enableOutput, sizeof(enableOutput));
err = AudioUnitSetProperty(ioUnit, kAudioOutputUnitProperty_SetInputCallback,
kAudioUnitScope_Input,
kOutputBus, &callbackStruct, sizeof(callbackStruct));
// Set the stream format.
size_t bytesPerSample = [self ASBDForSoundMode];
err = AudioUnitSetProperty(ioUnit, kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
kInputBus, &streamFormat, sizeof(streamFormat));
err = AudioUnitSetProperty(ioUnit, kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
kOutputBus, &streamFormat, sizeof(streamFormat));
// Disable system buffer allocation. We'll do it ourselves.
UInt32 flag = 0;
err = AudioUnitSetProperty(ioUnit, kAudioUnitProperty_ShouldAllocateBuffer,
kAudioUnitScope_Output,
kInputBus, &flag, sizeof(flag));
// Allocate AudioBuffers for use when listening.
// TODO: Move into initialization...should only be required once.
bufferList = (AudioBufferList *)malloc(sizeof(AudioBuffer));
bufferList->mNumberBuffers = 1;
bufferList->mBuffers[0].mNumberChannels = 1;
bufferList->mBuffers[0].mDataByteSize = 512*bytesPerSample;
bufferList->mBuffers[0].mData = calloc(512, bytesPerSample);
}
I managed to find and fix the issue, which was in an area of the code not posted above.
In a following step the output buffer was being converted into a different number format using an AudioConverter object. However, the converter object was not being disposed of, and remained live in the memory. I fixed it by using AudioConverterDispose as below:
err = AudioConverterNew(&inFormat, &outFormat, &converter);
err = AudioConverterConvertBuffer(converter, inSize, buf, &outSize, outputBuf);
err = AudioConverterDispose (converter);

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