/*

File: aqofflinerender.cpp

Abstract: Demonstrates the use of AudioQueueOfflineRender

Version: 1.0

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*/

// standard includes

#include <AudioToolbox/AudioQueue.h>

#include <AudioToolbox/AudioFile.h>

#include <AudioToolbox/ExtendedAudioFile.h>

// helpers

#include "CAXException.h"

#include "CAStreamBasicDescription.h"

// the application specific info we keep track of

struct AQTestInfo

{

AudioFileID mAudioFile;

CAStreamBasicDescription mDataFormat;

AudioQueueRef mQueue;

AudioQueueBufferRef mBuffer;

SInt64 mCurrentPacket;

UInt32 mNumPacketsToRead;

AudioStreamPacketDescription *mPacketDescs;

bool mFlushed;

bool mDone;

};

#pragma mark- Helper Functions

// ***********************

// CalculateBytesForTime Utility Function

// we only use time here as a guideline

// we are really trying to get somewhere between 16K and 64K buffers, but not allocate too much if we don't need it

void CalculateBytesForTime (CAStreamBasicDescription & inDesc, UInt32 inMaxPacketSize, Float64 inSeconds, UInt32 *outBufferSize, UInt32 *outNumPackets)

{

static const int maxBufferSize = 0x10000; // limit size to 64K

static const int minBufferSize = 0x4000; // limit size to 16K

if (inDesc.mFramesPerPacket) {

Float64 numPacketsForTime = inDesc.mSampleRate / inDesc.mFramesPerPacket * inSeconds;

*outBufferSize = numPacketsForTime * inMaxPacketSize;

} else {

// if frames per packet is zero, then the codec has no predictable packet == time

// so we can't tailor this (we don't know how many Packets represent a time period

// we'll just return a default buffer size

*outBufferSize = maxBufferSize > inMaxPacketSize ? maxBufferSize : inMaxPacketSize;

}

// we're going to limit our size to our default

if (*outBufferSize > maxBufferSize && *outBufferSize > inMaxPacketSize) {

*outBufferSize = maxBufferSize;

} else {

// also make sure we're not too small - we don't want to go the disk for too small chunks

if (*outBufferSize < minBufferSize) {

*outBufferSize = minBufferSize;

}

}

*outNumPackets = *outBufferSize / inMaxPacketSize;

}

#pragma mark- AQOutputCallback

// ***********************

// AudioQueueOutputCallback function used to push data into the audio queue

static void AQTestBufferCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inCompleteAQBuffer)

{

AQTestInfo * myInfo = (AQTestInfo *)inUserData;

if (myInfo->mDone) return;

UInt32 numBytes;

UInt32 nPackets = myInfo->mNumPacketsToRead;

OSStatus result = AudioFileReadPackets(myInfo->mAudioFile, // The audio file from which packets of audio data are to be read.

false, // Set to true to cache the data. Otherwise, set to false.

&numBytes, // On output, a pointer to the number of bytes actually returned.

myInfo->mPacketDescs, // A pointer to an array of packet descriptions that have been allocated.

myInfo->mCurrentPacket, // The packet index of the first packet you want to be returned.

&nPackets, // On input, a pointer to the number of packets to read. On output, the number of packets actually read.

inCompleteAQBuffer->mAudioData); // A pointer to user-allocated memory.

if (result) {

DebugMessageN1 ("Error reading from file: %d\n", (int)result);

exit(1);

}

// we have some data

if (nPackets > 0) {

inCompleteAQBuffer->mAudioDataByteSize = numBytes;

result = AudioQueueEnqueueBuffer(inAQ, // The audio queue that owns the audio queue buffer.

inCompleteAQBuffer, // The audio queue buffer to add to the buffer queue.

(myInfo->mPacketDescs ? nPackets : 0), // The number of packets of audio data in the inBuffer parameter. See Docs.

myInfo->mPacketDescs); // An array of packet descriptions. Or NULL. See Docs.

if (result) {

DebugMessageN1 ("Error enqueuing buffer: %d\n", (int)result);

exit(1);

}

myInfo->mCurrentPacket += nPackets;

} else {

// **** This ensures that we flush the queue when done -- ensures you get all the data out ****

if (!myInfo->mFlushed) {

result = AudioQueueFlush(myInfo->mQueue);

if (result) {

DebugMessageN1("AudioQueueFlush failed: %d", (int)result);

exit(1);

}

myInfo->mFlushed = true;

}

result = AudioQueueStop(myInfo->mQueue, false);

if (result) {

DebugMessageN1("AudioQueueStop(false) failed: %d", (int)result);

exit(1);

}

// reading nPackets == 0 is our EOF condition

myInfo->mDone = true;

}

}

// ***********************

#pragma mark- Main Render Function

void DoAQOfflineRender(CFURLRef sourceURL, CFURLRef destinationURL)

{

// main audio queue code

try {

AQTestInfo myInfo;

myInfo.mDone = false;

myInfo.mFlushed = false;

myInfo.mCurrentPacket = 0;

// get the source file

XThrowIfError(AudioFileOpenURL(sourceURL, 0x01/*fsRdPerm*/, 0/*inFileTypeHint*/, &myInfo.mAudioFile), "AudioFileOpen failed");

UInt32 size = sizeof(myInfo.mDataFormat);

XThrowIfError(AudioFileGetProperty(myInfo.mAudioFile, kAudioFilePropertyDataFormat, &size, &myInfo.mDataFormat), "couldn't get file's data format");

printf ("File format: "); myInfo.mDataFormat.Print();

// create a new audio queue output

XThrowIfError(AudioQueueNewOutput(&myInfo.mDataFormat, // The data format of the audio to play. For linear PCM, only interleaved formats are supported.

AQTestBufferCallback, // A callback function to use with the playback audio queue.

&myInfo, // A custom data structure for use with the callback function.

CFRunLoopGetCurrent(), // The event loop on which the callback function pointed to by the inCallbackProc parameter is to be called.

// If you specify NULL, the callback is invoked on one of the audio queue’s internal threads.

kCFRunLoopCommonModes, // The run loop mode in which to invoke the callback function specified in the inCallbackProc parameter.

0, // Reserved for future use. Must be 0.

&myInfo.mQueue), // On output, the newly created playback audio queue object.

"AudioQueueNew failed");

UInt32 bufferByteSize;

// we need to calculate how many packets we read at a time and how big a buffer we need

// we base this on the size of the packets in the file and an approximate duration for each buffer

{

bool isFormatVBR = (myInfo.mDataFormat.mBytesPerPacket == 0 || myInfo.mDataFormat.mFramesPerPacket == 0);

// first check to see what the max size of a packet is - if it is bigger

// than our allocation default size, that needs to become larger

UInt32 maxPacketSize;

size = sizeof(maxPacketSize);

XThrowIfError(AudioFileGetProperty(myInfo.mAudioFile, kAudioFilePropertyPacketSizeUpperBound, &size, &maxPacketSize), "couldn't get file's max packet size");

// adjust buffer size to represent about a second of audio based on this format

CalculateBytesForTime(myInfo.mDataFormat, maxPacketSize, 1.0/*seconds*/, &bufferByteSize, &myInfo.mNumPacketsToRead);

if (isFormatVBR) {

myInfo.mPacketDescs = new AudioStreamPacketDescription [myInfo.mNumPacketsToRead];

} else {

myInfo.mPacketDescs = NULL; // we don't provide packet descriptions for constant bit rate formats (like linear PCM)

}

printf ("Buffer Byte Size: %d, Num Packets to Read: %d\n", (int)bufferByteSize, (int)myInfo.mNumPacketsToRead);

}

// if the file has a magic cookie, we should get it and set it on the AQ

size = sizeof(UInt32);

OSStatus result = AudioFileGetPropertyInfo (myInfo.mAudioFile, kAudioFilePropertyMagicCookieData, &size, NULL);

if (!result && size) {

char* cookie = new char [size];

XThrowIfError (AudioFileGetProperty (myInfo.mAudioFile, kAudioFilePropertyMagicCookieData, &size, cookie), "get cookie from file");

XThrowIfError (AudioQueueSetProperty(myInfo.mQueue, kAudioQueueProperty_MagicCookie, cookie, size), "set cookie on queue");

delete [] cookie;

}

// channel layout?

OSStatus err = AudioFileGetPropertyInfo(myInfo.mAudioFile, kAudioFilePropertyChannelLayout, &size, NULL);

AudioChannelLayout *acl = NULL;

if (err == noErr && size > 0) {

acl = (AudioChannelLayout *)malloc(size);

XThrowIfError(AudioFileGetProperty(myInfo.mAudioFile, kAudioFilePropertyChannelLayout, &size, acl), "get audio file's channel layout");

XThrowIfError(AudioQueueSetProperty(myInfo.mQueue, kAudioQueueProperty_ChannelLayout, acl, size), "set channel layout on queue");

}

//allocate the input read buffer

XThrowIfError(AudioQueueAllocateBuffer(myInfo.mQueue, bufferByteSize, &myInfo.mBuffer), "AudioQueueAllocateBuffer");

// prepare a canonical interleaved capture format

CAStreamBasicDescription captureFormat;

captureFormat.mSampleRate = myInfo.mDataFormat.mSampleRate;

captureFormat.SetAUCanonical(myInfo.mDataFormat.mChannelsPerFrame, true); // interleaved

XThrowIfError(AudioQueueSetOfflineRenderFormat(myInfo.mQueue, &captureFormat, acl), "set offline render format");

ExtAudioFileRef captureFile;

// prepare a 16-bit int file format, sample channel count and sample rate

CAStreamBasicDescription dstFormat;

dstFormat.mSampleRate = myInfo.mDataFormat.mSampleRate;

dstFormat.mChannelsPerFrame = myInfo.mDataFormat.mChannelsPerFrame;

dstFormat.mFormatID = kAudioFormatLinearPCM;

dstFormat.mFormatFlags = kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsSignedInteger; // little-endian

dstFormat.mBitsPerChannel = 16;

dstFormat.mBytesPerPacket = dstFormat.mBytesPerFrame = 2 * dstFormat.mChannelsPerFrame;

dstFormat.mFramesPerPacket = 1;

// create the capture file

XThrowIfError(ExtAudioFileCreateWithURL(destinationURL, kAudioFileCAFType, &dstFormat, acl, kAudioFileFlags_EraseFile, &captureFile), "ExtAudioFileCreateWithURL");

// set the capture file's client format to be the canonical format from the queue

XThrowIfError(ExtAudioFileSetProperty(captureFile, kExtAudioFileProperty_ClientDataFormat, sizeof(AudioStreamBasicDescription), &captureFormat), "set ExtAudioFile client format");

// allocate the capture buffer, just keep it at half the size of the enqueue buffer

// we don't ever want to pull any faster than we can push data in for render

// this 2:1 ratio keeps the AQ Offline Render happy

const UInt32 captureBufferByteSize = bufferByteSize / 2;

AudioQueueBufferRef captureBuffer;

AudioBufferList captureABL;

XThrowIfError(AudioQueueAllocateBuffer(myInfo.mQueue, captureBufferByteSize, &captureBuffer), "AudioQueueAllocateBuffer");

captureABL.mNumberBuffers = 1;

captureABL.mBuffers[0].mData = captureBuffer->mAudioData;

captureABL.mBuffers[0].mNumberChannels = captureFormat.mChannelsPerFrame;

// lets start playing now - stop is called in the AQTestBufferCallback when there's

// no more to read from the file

XThrowIfError(AudioQueueStart(myInfo.mQueue, NULL), "AudioQueueStart failed");

AudioTimeStamp ts;

ts.mFlags = kAudioTimeStampSampleTimeValid;

ts.mSampleTime = 0;

// we need to call this once asking for 0 frames

XThrowIfError(AudioQueueOfflineRender(myInfo.mQueue, &ts, captureBuffer, 0), "AudioQueueOfflineRender");

// we need to enqueue a buffer after the queue has started

AQTestBufferCallback(&myInfo, myInfo.mQueue, myInfo.mBuffer);

while (true) {

UInt32 reqFrames = captureBufferByteSize / captureFormat.mBytesPerFrame;

XThrowIfError(AudioQueueOfflineRender(myInfo.mQueue, &ts, captureBuffer, reqFrames), "AudioQueueOfflineRender");

captureABL.mBuffers[0].mData = captureBuffer->mAudioData;

captureABL.mBuffers[0].mDataByteSize = captureBuffer->mAudioDataByteSize;

UInt32 writeFrames = captureABL.mBuffers[0].mDataByteSize / captureFormat.mBytesPerFrame;

printf("t = %.f: AudioQueueOfflineRender: req %d fr/%d bytes, got %ld fr/%d bytes\n", ts.mSampleTime, (int)reqFrames, (int)captureBufferByteSize, writeFrames, (int)captureABL.mBuffers[0].mDataByteSize);

XThrowIfError(ExtAudioFileWrite(captureFile, writeFrames, &captureABL), "ExtAudioFileWrite");

if (myInfo.mFlushed) break;

ts.mSampleTime += writeFrames;

}

CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1, false);

XThrowIfError(AudioQueueDispose(myInfo.mQueue, true), "AudioQueueDispose(true) failed");

XThrowIfError(AudioFileClose(myInfo.mAudioFile), "AudioQueueDispose(false) failed");

XThrowIfError(ExtAudioFileDispose(captureFile), "ExtAudioFileDispose failed");

if (myInfo.mPacketDescs) delete [] myInfo.mPacketDescs;

if (acl) free(acl);

}

catch (CAXException e) {

char buf[256];

fprintf(stderr, "Error: %s (%s)\n", e.mOperation, e.FormatError(buf));

}

return;

}