给你。完整的工作示例。应该在mediaserverd 守护进程中加载调整。它将记录/var/mobile/Media/DCIM/result.m4a中的每个电话。音频文件有两个通道。左边是麦克风,右边是扬声器。在 iPhone 4S 上,仅当扬声器打开时才会记录通话。在 iPhone 5 上,5C 和 5S 通话都会以任何一种方式录制。切换到/从扬声器时可能会出现小问题,但录音会继续。
#import <AudioToolbox/AudioToolbox.h>
#import <libkern/OSAtomic.h>
//CoreTelephony.framework
extern "C" CFStringRef const kCTCallStatusChangeNotification;
extern "C" CFStringRef const kCTCallStatus;
extern "C" id CTTelephonyCenterGetDefault();
extern "C" void CTTelephonyCenterAddObserver(id ct, void* observer, CFNotificationCallback callBack, CFStringRef name, void *object, CFNotificationSuspensionBehavior sb);
extern "C" int CTGetCurrentCallCount();
enum
{
kCTCallStatusActive = 1,
kCTCallStatusHeld = 2,
kCTCallStatusOutgoing = 3,
kCTCallStatusIncoming = 4,
kCTCallStatusHanged = 5
};
NSString* kMicFilePath = @"/var/mobile/Media/DCIM/mic.caf";
NSString* kSpeakerFilePath = @"/var/mobile/Media/DCIM/speaker.caf";
NSString* kResultFilePath = @"/var/mobile/Media/DCIM/result.m4a";
OSSpinLock phoneCallIsActiveLock = 0;
OSSpinLock speakerLock = 0;
OSSpinLock micLock = 0;
ExtAudioFileRef micFile = NULL;
ExtAudioFileRef speakerFile = NULL;
BOOL phoneCallIsActive = NO;
void Convert()
{
//File URLs
CFURLRef micUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kMicFilePath, kCFURLPOSIXPathStyle, false);
CFURLRef speakerUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kSpeakerFilePath, kCFURLPOSIXPathStyle, false);
CFURLRef mixUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kResultFilePath, kCFURLPOSIXPathStyle, false);
ExtAudioFileRef micFile = NULL;
ExtAudioFileRef speakerFile = NULL;
ExtAudioFileRef mixFile = NULL;
//Opening input files (speaker and mic)
ExtAudioFileOpenURL(micUrl, &micFile);
ExtAudioFileOpenURL(speakerUrl, &speakerFile);
//Reading input file audio format (mono LPCM)
AudioStreamBasicDescription inputFormat, outputFormat;
UInt32 descSize = sizeof(inputFormat);
ExtAudioFileGetProperty(micFile, kExtAudioFileProperty_FileDataFormat, &descSize, &inputFormat);
int sampleSize = inputFormat.mBytesPerFrame;
//Filling input stream format for output file (stereo LPCM)
FillOutASBDForLPCM(inputFormat, inputFormat.mSampleRate, 2, inputFormat.mBitsPerChannel, inputFormat.mBitsPerChannel, true, false, false);
//Filling output file audio format (AAC)
memset(&outputFormat, 0, sizeof(outputFormat));
outputFormat.mFormatID = kAudioFormatMPEG4AAC;
outputFormat.mSampleRate = 8000;
outputFormat.mFormatFlags = kMPEG4Object_AAC_Main;
outputFormat.mChannelsPerFrame = 2;
//Opening output file
ExtAudioFileCreateWithURL(mixUrl, kAudioFileM4AType, &outputFormat, NULL, kAudioFileFlags_EraseFile, &mixFile);
ExtAudioFileSetProperty(mixFile, kExtAudioFileProperty_ClientDataFormat, sizeof(inputFormat), &inputFormat);
//Freeing URLs
CFRelease(micUrl);
CFRelease(speakerUrl);
CFRelease(mixUrl);
//Setting up audio buffers
int bufferSizeInSamples = 64 * 1024;
AudioBufferList micBuffer;
micBuffer.mNumberBuffers = 1;
micBuffer.mBuffers[0].mNumberChannels = 1;
micBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples;
micBuffer.mBuffers[0].mData = malloc(micBuffer.mBuffers[0].mDataByteSize);
AudioBufferList speakerBuffer;
speakerBuffer.mNumberBuffers = 1;
speakerBuffer.mBuffers[0].mNumberChannels = 1;
speakerBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples;
speakerBuffer.mBuffers[0].mData = malloc(speakerBuffer.mBuffers[0].mDataByteSize);
AudioBufferList mixBuffer;
mixBuffer.mNumberBuffers = 1;
mixBuffer.mBuffers[0].mNumberChannels = 2;
mixBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples * 2;
mixBuffer.mBuffers[0].mData = malloc(mixBuffer.mBuffers[0].mDataByteSize);
//Converting
while (true)
{
//Reading data from input files
UInt32 framesToRead = bufferSizeInSamples;
ExtAudioFileRead(micFile, &framesToRead, &micBuffer);
ExtAudioFileRead(speakerFile, &framesToRead, &speakerBuffer);
if (framesToRead == 0)
{
break;
}
//Building interleaved stereo buffer - left channel is mic, right - speaker
for (int i = 0; i < framesToRead; i++)
{
memcpy((char*)mixBuffer.mBuffers[0].mData + i * sampleSize * 2, (char*)micBuffer.mBuffers[0].mData + i * sampleSize, sampleSize);
memcpy((char*)mixBuffer.mBuffers[0].mData + i * sampleSize * 2 + sampleSize, (char*)speakerBuffer.mBuffers[0].mData + i * sampleSize, sampleSize);
}
//Writing to output file - LPCM will be converted to AAC
ExtAudioFileWrite(mixFile, framesToRead, &mixBuffer);
}
//Closing files
ExtAudioFileDispose(micFile);
ExtAudioFileDispose(speakerFile);
ExtAudioFileDispose(mixFile);
//Freeing audio buffers
free(micBuffer.mBuffers[0].mData);
free(speakerBuffer.mBuffers[0].mData);
free(mixBuffer.mBuffers[0].mData);
}
void Cleanup()
{
[[NSFileManager defaultManager] removeItemAtPath:kMicFilePath error:NULL];
[[NSFileManager defaultManager] removeItemAtPath:kSpeakerFilePath error:NULL];
}
void CoreTelephonyNotificationCallback(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo)
{
NSDictionary* data = (NSDictionary*)userInfo;
if ([(NSString*)name isEqualToString:(NSString*)kCTCallStatusChangeNotification])
{
int currentCallStatus = [data[(NSString*)kCTCallStatus] integerValue];
if (currentCallStatus == kCTCallStatusActive)
{
OSSpinLockLock(&phoneCallIsActiveLock);
phoneCallIsActive = YES;
OSSpinLockUnlock(&phoneCallIsActiveLock);
}
else if (currentCallStatus == kCTCallStatusHanged)
{
if (CTGetCurrentCallCount() > 0)
{
return;
}
OSSpinLockLock(&phoneCallIsActiveLock);
phoneCallIsActive = NO;
OSSpinLockUnlock(&phoneCallIsActiveLock);
//Closing mic file
OSSpinLockLock(&micLock);
if (micFile != NULL)
{
ExtAudioFileDispose(micFile);
}
micFile = NULL;
OSSpinLockUnlock(&micLock);
//Closing speaker file
OSSpinLockLock(&speakerLock);
if (speakerFile != NULL)
{
ExtAudioFileDispose(speakerFile);
}
speakerFile = NULL;
OSSpinLockUnlock(&speakerLock);
Convert();
Cleanup();
}
}
}
OSStatus(*AudioUnitProcess_orig)(AudioUnit unit, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inNumberFrames, AudioBufferList *ioData);
OSStatus AudioUnitProcess_hook(AudioUnit unit, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inNumberFrames, AudioBufferList *ioData)
{
OSSpinLockLock(&phoneCallIsActiveLock);
if (phoneCallIsActive == NO)
{
OSSpinLockUnlock(&phoneCallIsActiveLock);
return AudioUnitProcess_orig(unit, ioActionFlags, inTimeStamp, inNumberFrames, ioData);
}
OSSpinLockUnlock(&phoneCallIsActiveLock);
ExtAudioFileRef* currentFile = NULL;
OSSpinLock* currentLock = NULL;
AudioComponentDescription unitDescription = {0};
AudioComponentGetDescription(AudioComponentInstanceGetComponent(unit), &unitDescription);
//'agcc', 'mbdp' - iPhone 4S, iPhone 5
//'agc2', 'vrq2' - iPhone 5C, iPhone 5S
if (unitDescription.componentSubType == 'agcc' || unitDescription.componentSubType == 'agc2')
{
currentFile = &micFile;
currentLock = &micLock;
}
else if (unitDescription.componentSubType == 'mbdp' || unitDescription.componentSubType == 'vrq2')
{
currentFile = &speakerFile;
currentLock = &speakerLock;
}
if (currentFile != NULL)
{
OSSpinLockLock(currentLock);
//Opening file
if (*currentFile == NULL)
{
//Obtaining input audio format
AudioStreamBasicDescription desc;
UInt32 descSize = sizeof(desc);
AudioUnitGetProperty(unit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &desc, &descSize);
//Opening audio file
CFURLRef url = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)((currentFile == &micFile) ? kMicFilePath : kSpeakerFilePath), kCFURLPOSIXPathStyle, false);
ExtAudioFileRef audioFile = NULL;
OSStatus result = ExtAudioFileCreateWithURL(url, kAudioFileCAFType, &desc, NULL, kAudioFileFlags_EraseFile, &audioFile);
if (result != 0)
{
*currentFile = NULL;
}
else
{
*currentFile = audioFile;
//Writing audio format
ExtAudioFileSetProperty(*currentFile, kExtAudioFileProperty_ClientDataFormat, sizeof(desc), &desc);
}
CFRelease(url);
}
else
{
//Writing audio buffer
ExtAudioFileWrite(*currentFile, inNumberFrames, ioData);
}
OSSpinLockUnlock(currentLock);
}
return AudioUnitProcess_orig(unit, ioActionFlags, inTimeStamp, inNumberFrames, ioData);
}
__attribute__((constructor))
static void initialize()
{
CTTelephonyCenterAddObserver(CTTelephonyCenterGetDefault(), NULL, CoreTelephonyNotificationCallback, NULL, NULL, CFNotificationSuspensionBehaviorHold);
MSHookFunction(AudioUnitProcess, AudioUnitProcess_hook, &AudioUnitProcess_orig);
}
关于正在发生的事情的几句话。 AudioUnitProcess 函数用于处理音频流以应用一些效果、混合、转换等。我们正在挂钩 AudioUnitProcess 以访问电话的音频流。当电话通话处于活动状态时,这些流正在以各种方式进行处理。
我们正在侦听 CoreTelephony 通知,以获取电话呼叫状态的变化。当我们收到音频样本时,我们需要确定它们来自哪里——麦克风或扬声器。这是使用AudioComponentDescription 结构中的componentSubType 字段完成的。现在,您可能会想,我们为什么不存储AudioUnit 对象,这样我们就不需要每次都检查componentSubType。我这样做了,但是当您在 iPhone 5 上打开/关闭扬声器时,它会破坏一切,因为 AudioUnit 对象会改变,它们会被重新创建。所以,现在我们打开音频文件(一个用于麦克风,一个用于扬声器)并在其中写入样本,就这么简单。当电话结束时,我们将收到适当的 CoreTelephony 通知并关闭文件。我们有两个单独的文件,其中包含需要合并的麦克风和扬声器的音频。这就是void Convert() 的用途。如果您了解 API,这非常简单。我觉得不用解释了,cmets就够了。
关于锁。 mediaserverd 中有很多线程。音频处理和 CoreTelephony 通知在不同的线程上,所以我们需要某种同步。我选择自旋锁是因为它们速度很快,而且在我们的例子中锁竞争的可能性很小。在 iPhone 4S 甚至 iPhone 5 上,AudioUnitProcess 中的所有工作都应该尽快完成,否则您会听到设备扬声器发出的打嗝声,这显然不好。