问题
I'm looking at this example: https://developer.apple.com/library/ios/#samplecode/SpeakHere/Introduction/Intro.html
I modified it ( the AQRecorder.mm)to record mp3 instead of caf file. I changed from kAudioFileCAFType to kAudioFileMP3Type but it does not create the file.
The code became
void AQRecorder::SetupAudioFormat(UInt32 inFormatID)
{
memset(&mRecordFormat, 0, sizeof(mRecordFormat));
UInt32 size = sizeof(mRecordFormat.mSampleRate);
XThrowIfError(AudioSessionGetProperty( kAudioSessionProperty_CurrentHardwareSampleRate,
&size,
&mRecordFormat.mSampleRate), "couldn't get hardware sample rate");
size = sizeof(mRecordFormat.mChannelsPerFrame);
XThrowIfError(AudioSessionGetProperty( kAudioSessionProperty_CurrentHardwareInputNumberChannels,
&size,
&mRecordFormat.mChannelsPerFrame), "couldn't get input channel count");
mRecordFormat.mFormatID = inFormatID;
if (inFormatID == kAudioFormatLinearPCM)
{
// if we want pcm, default to signed 16-bit little-endian
mRecordFormat.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kLinearPCMFormatFlagIsPacked;
mRecordFormat.mBitsPerChannel = 16;
mRecordFormat.mBytesPerPacket = mRecordFormat.mBytesPerFrame = (mRecordFormat.mBitsPerChannel / 8) * mRecordFormat.mChannelsPerFrame;
mRecordFormat.mFramesPerPacket = 1;
}
}
void AQRecorder::StartRecord(CFStringRef inRecordFile)
{
int i, bufferByteSize;
UInt32 size;
CFURLRef url;
try {
mFileName = CFStringCreateCopy(kCFAllocatorDefault, inRecordFile);
// specify the recording format
SetupAudioFormat(kAudioFormatLinearPCM);
// create the queue
XThrowIfError(AudioQueueNewInput(
&mRecordFormat,
MyInputBufferHandler,
this /* userData */,
NULL /* run loop */, NULL /* run loop mode */,
0 /* flags */, &mQueue), "AudioQueueNewInput failed");
// get the record format back from the queue's audio converter --
// the file may require a more specific stream description than was necessary to create the encoder.
mRecordPacket = 0;
size = sizeof(mRecordFormat);
XThrowIfError(AudioQueueGetProperty(mQueue, kAudioQueueProperty_StreamDescription,
&mRecordFormat, &size), "couldn't get queue's format");
NSString *recordFile = [NSTemporaryDirectory() stringByAppendingPathComponent: (NSString*)inRecordFile];
NSLog(recordFile);
url = CFURLCreateWithString(kCFAllocatorDefault, (CFStringRef)recordFile, NULL);
// create the audio file kAudioFileCAFType
XThrowIfError(AudioFileCreateWithURL(url, kAudioFileMP3Type, &mRecordFormat, kAudioFileFlags_EraseFile,
&mRecordFile), "AudioFileCreateWithURL failed");
CFRelease(url);
// copy the cookie first to give the file object as much info as we can about the data going in
// not necessary for pcm, but required for some compressed audio
CopyEncoderCookieToFile();
// allocate and enqueue buffers
bufferByteSize = ComputeRecordBufferSize(&mRecordFormat, kBufferDurationSeconds); // enough bytes for half a second
for (i = 0; i < kNumberRecordBuffers; ++i) {
XThrowIfError(AudioQueueAllocateBuffer(mQueue, bufferByteSize, &mBuffers[i]),
"AudioQueueAllocateBuffer failed");
XThrowIfError(AudioQueueEnqueueBuffer(mQueue, mBuffers[i], 0, NULL),
"AudioQueueEnqueueBuffer failed");
}
// start the queue
mIsRunning = true;
XThrowIfError(AudioQueueStart(mQueue, NULL), "AudioQueueStart failed");
}
catch (CAXException &e) {
char buf[256];
fprintf(stderr, "Error: %s (%s)\n", e.mOperation, e.FormatError(buf));
}
catch (...) {
fprintf(stderr, "An unknown error occurred\n");
}
}
Am I missing any settings, or what's wrong with my code? , mp3 be supported from apple https://developer.apple.com/library/mac/#documentation/MusicAudio/Reference/AudioFileConvertRef/Reference/reference.html
回答1:
iOS devices don't support recording to the MP3 encoding format. Actually, I don't think any of the iOS devices do. You have to choose an alternate format. Core Audio can read, but not write, MP3 files.
回答2:
You can use Lame library for encoding caf to mp3 file format. Check this sample iOSMp3Recorder
来源:https://stackoverflow.com/questions/9399019/recording-mp3-instead-of-caf-file