我猜“ AudioConverterFillComplexBuffer”是解决方案。
但我不知道这种方式是否正确。
+1。音频单元
初始化 AudioUnit ：“recordingCallback”是回调方法。输出格式为 PCM。记录到文件。（我播放了录制的文件）。
+2。音频转换器
添加“AudioConverterFillComplexBuffer”我不太了解。添加，
+3。问题
“audioConverterComplexInputDataProc”方法只调用了一次。
如何使用 AudioConverter api？
附上我的代码
#import "AACAudioRecorder.h"
#define kOutputBus 0
#define kInputBus 1
@implementation AACAudioRecorder
这是 AudioConverterFillComplexBuffer 的回调方法。
static OSStatus audioConverterComplexInputDataProc( AudioConverterRef inAudioConverter,
UInt32* ioNumberDataPackets,
AudioBufferList* ioData,
AudioStreamPacketDescription** outDataPacketDescription,
void* inUserData){
ioData = (AudioBufferList*)inUserData;
return 0;
}
这是 AudioUnit 的回调。
static OSStatus recordingCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
@autoreleasepool {
AudioBufferList *bufferList;
AACAudioRecorder *THIS = (AACAudioRecorder *)inRefCon;
OSStatus err = AudioUnitRender(THIS-> m_audioUnit ,
ioActionFlags,
inTimeStamp, 1, inNumberFrames, bufferList);
if (err) { NSLog(@"%s AudioUnitRender error %d\n",__FUNCTION__, (int)err); return err; }
NSString *recordFile =
[NSTemporaryDirectory() stringByAppendingPathComponent: @"auioBuffer.pcm"];
FILE *fp;
fp = fopen([recordFile UTF8String], "a+");
fwrite(bufferList->mBuffers[0].mData, sizeof(Byte),
bufferList->mBuffers[0].mDataByteSize, fp);
fclose(fp);
[THIS convert:bufferList ioOutputDataPacketSize:&inNumberFrames];
if (err) {NSLog(@"%s : AudioFormat Convert error %d\n",__FUNCTION__, (int)err); }
}
return noErr;
}
状态检查方法
static void checkStatus(OSStatus status, const char* str){
if (status != noErr) {
NSLog(@"%s %s error : %ld ",__FUNCTION__, str, status);
}
}
转换方法：PCM -> AAC
- (void)convert:(AudioBufferList*)input_bufferList ioOutputDataPacketSize:(UInt32*)packetSizeRef
{
UInt32 size = sizeof(UInt32);
UInt32 maxOutputSize;
AudioConverterGetProperty(m_audioConverterRef,
kAudioConverterPropertyMaximumOutputPacketSize,
&size,
&maxOutputSize);
AudioBufferList *output_bufferList = (AudioBufferList *)malloc(sizeof(AudioBufferList));
output_bufferList->mNumberBuffers = 1;
output_bufferList->mBuffers[0].mNumberChannels = 1;
output_bufferList->mBuffers[0].mDataByteSize = *packetSizeRef * 2;
output_bufferList->mBuffers[0].mData = (AudioUnitSampleType *)malloc(*packetSizeRef * 2);
OSStatus err;
err = AudioConverterFillComplexBuffer(
m_audioConverterRef,
audioConverterComplexInputDataProc,
input_bufferList,
packetSizeRef,
output_bufferList,
NULL
);
if (err) {NSLog(@"%s : AudioFormat Convert error %d\n",__FUNCTION__, (int)err); }
}
这是初始化方法。
- (void)initialize
{
// ...
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
status = AudioComponentInstanceNew(inputComponent, &m_audioUnit);
checkStatus(status,"AudioComponentInstanceNew");
// Enable IO for recording
UInt32 flag = 1;
status = AudioUnitSetProperty(m_audioUnit,
kAudioOutputUnitProperty_EnableIO,
kAudioUnitScope_Input,
kInputBus,
&flag,
sizeof(flag));
checkStatus(status,"Enable IO for recording");
// Enable IO for playback
status = AudioUnitSetProperty(m_audioUnit,
kAudioOutputUnitProperty_EnableIO,
kAudioUnitScope_Output,
kOutputBus,
&flag,
sizeof(flag));
checkStatus(status,"Enable IO for playback");
// Describe format
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;
// Apply format
status = AudioUnitSetProperty(m_audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Output,
kInputBus,
&audioFormat,
sizeof(audioFormat));
checkStatus(status,"Apply format1");
status = AudioUnitSetProperty(m_audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
kOutputBus,
&audioFormat,
sizeof(audioFormat));
checkStatus(status,"Apply format2");
// Set input callback
AURenderCallbackStruct callbackStruct;
callbackStruct.inputProc = recordingCallback;
callbackStruct.inputProcRefCon = self;
status = AudioUnitSetProperty(m_audioUnit,
kAudioOutputUnitProperty_SetInputCallback,
kAudioUnitScope_Global,
kInputBus,
&callbackStruct,
sizeof(callbackStruct));
checkStatus(status,"Set input callback");
// Initialise
status = AudioUnitInitialize(m_audioUnit);
checkStatus(status,"AudioUnitInitialize");
// Set ASBD For converting Output Stream
AudioStreamBasicDescription outputFormat;
memset(&outputFormat, 0, sizeof(outputFormat));
outputFormat.mSampleRate = 44100.00;
outputFormat.mFormatID = kAudioFormatMPEG4AAC;
outputFormat.mFormatFlags = kMPEG4Object_AAC_Main;
outputFormat.mFramesPerPacket = 1024;
outputFormat.mChannelsPerFrame = 1;
outputFormat.mBitsPerChannel = 0;
outputFormat.mBytesPerFrame = 0;
outputFormat.mBytesPerPacket = 0;
//Create An Audio Converter
status = AudioConverterNew( &audioFormat, &outputFormat, &m_audioConverterRef );
checkStatus(status,"Create An Audio Converter");
if(m_audioConverterRef) NSLog(@"m_audioConverterRef is created");
}
AudioOutputUnitStart
- (void)StartRecord
{
OSStatus status = AudioOutputUnitStart(m_audioUnit);
checkStatus(status,"AudioOutputUnitStart");
}
音频输出单元停止
- (void)StopRecord
{
OSStatus status = AudioOutputUnitStop(m_audioUnit);
checkStatus(status,"AudioOutputUnitStop");
}
结束
- (void)finish
{
AudioUnitUninitialize(m_audioUnit);
}
@end