TPCircularBuffer Recording for later Playback
TPCircularBuffer Recording for later Playback
- Subject: TPCircularBuffer Recording for later Playback
- From: Pier <email@hidden>
- Date: Wed, 31 Oct 2012 14:24:02 +0800
Hi,
I'm trying to write a bunch of samples to a a TPCircularBuffer, provided Michael Tyson by http://atastypixel.com/blog/a-simple-fast-circular-buffer-implementation-for-audio-processing/comment-page-1/#comment-4988
I am successful in playing back these recorded samples in real time. Something like a monitor.
However, I wish to keep the samples in the TPCircularBuffer for later playback, and so I implemented 2 flags, rio->recording and rio->playing.
My idea was that I would activate rio->recording to be YES using a button. Record for a while, and then stop recording by setting the flag to be NO. Theoretically, TPCircularBuffer would have my audio info saved.
However, when I activate rio->playing to be YES in the playback Callback, I simply hear some jittery sound that has no semblance of what I recorded.
Am I using the buffer correctly? Or is this usually done another way?
Thanks.
Pier.
static OSStatus recordingCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
RIO *rio = (RIO*)inRefCon;
AudioUnit rioUnit = rio->theAudioUnit;
//ExtAudioFileRef eaf = rio->outEAF;
AudioBufferList abl = rio->audioBufferList;
SInt32 samples[NUMBER_OF_SAMPLES]; // A large enough size to not have to worry about buffer overrun
abl.mNumberBuffers = 1;
abl.mBuffers[0].mData = &samples;
abl.mBuffers[0].mNumberChannels = 1;
abl.mBuffers[0].mDataByteSize = inNumberFrames * sizeof(SInt16);
OSStatus result;
result = AudioUnitRender(rioUnit,
ioActionFlags,
inTimeStamp,
inBusNumber,
inNumberFrames,
&abl);
if (noErr != result) { NSLog(@"Obtain recorded samples error"); }
// React to a recording flag, if recording, save the abl into own buffer, else ignore
if (rio->recording)
{
TPCircularBufferProduceBytes(&rio->buffer, abl.mBuffers[0].mData, inNumberFrames * sizeof(SInt16));
NSLog(@"Recording!");
}
else
{
NSLog(@"Not Recording!");
}
// once stop recording save the circular buffer to a temp circular buffer
return noErr;
}
static OSStatus playbackCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
RIO *rio = (RIO*)inRefCon;
int bytesToCopy = ioData->mBuffers[0].mDataByteSize;
SInt16 *targetBuffer = (SInt16*)ioData->mBuffers[0].mData;
// Pull audio from playthrough buffer
int32_t availableBytes;
if (rio->playing)
{
SInt16 * tempbuffer = TPCircularBufferTail(&rio->buffer, &availableBytes);
memcpy(targetBuffer, tempbuffer, MIN(bytesToCopy, availableBytes));
TPCircularBufferConsume(&rio->buffer, MIN(bytesToCopy, availableBytes));
NSLog(@"Playing!");
}
else
{
NSLog(@"Playing silence!");
for (int i = 0 ; i < ioData->mNumberBuffers; i++){
//get the buffer to be filled
AudioBuffer buffer = ioData->mBuffers[i];
UInt32 *frameBuffer = buffer.mData;
//loop through the buffer and fill the frames
for (int j = 0; j < inNumberFrames; j++){
frameBuffer[j] = 0;
}
}
}
return noErr;
}
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