How to start recording an existing AudioQueue in response to an event?

Question

I am writing a class that opens an AudioQueue and analyzes its characteristics, and then, under certain conditions, can start or end recording a file from this AudioQueue that has already been created. This is my code (entirely based on SpeakHere) that opens AudioQueue without writing anything to tmp:

void AQRecorder::StartListen() {
int i, bufferByteSize;
UInt32 size;

try {       

    SetupAudioFormat(kAudioFormatLinearPCM);

    XThrowIfError(AudioQueueNewInput(&mRecordFormat,
                    MyInputBufferHandler,
                    this,
                    NULL, NULL,
                    0, &mQueue), "AudioQueueNewInput failed");

    mRecordPacket = 0;

    size = sizeof(mRecordFormat);
    XThrowIfError(AudioQueueGetProperty(mQueue, kAudioQueueProperty_StreamDescription,  
            &mRecordFormat, &size), "couldn't get queue format");

    bufferByteSize = ComputeRecordBufferSize(&mRecordFormat, kBufferDurationSeconds);
    for (i = 0; i < kNumberRecordBuffers; ++i) {
        XThrowIfError(AudioQueueAllocateBuffer(mQueue, bufferByteSize, &mBuffers[i]),
                      "AudioQueueAllocateBuffer failed");
        XThrowIfError(AudioQueueEnqueueBuffer(mQueue, mBuffers[i], 0, NULL),
                      "AudioQueueEnqueueBuffer failed");
    }

    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");
}
}

But I don’t understand a bit how to write a function that tells this queue "from now on to the stop signal, start writing this queue to tmp as a file." I understand how to tell AudioQueue to record as a file at the time it was created, how to set the file format, etc., but not how to tell it to start and stop the middle of the stream. Thanks so much for any pointers, thanks.

Answer 1

/ AudioQueuePause (AudioQueueRef inAQ) AudioQueueStart (AudioQueueRef inAQ, const AudioTimeStamp * inStartTime);

. , , .

, bool, "doWrite" , , YES. , , . doWrite = YES . (, , , - ).

void AQRecorder::MyInputBufferHandler(  void * inUserData, AudioQueueRef    inAQ, AudioQueueBufferRef inBuffer, const AudioTimeStamp * inStartTime, UInt32  inNumPackets, const  AudioStreamPacketDescription* inPacketDesc)
{
    AQRecorder *aqr = (AQRecorder *)inUserData;
    try {
        if (inNumPackets > 0) {

                    if (aqr.doWrite){
                            // write packets to file
                            XThrowIfError(AudioFileWritePackets(aqr->mRecordFile, FALSE, inBuffer->mAudioDataByteSize, inPacketDesc, aqr->mRecordPacket, &inNumPackets, inBuffer->mAudioData), "AudioFileWritePackets failed");
                            aqr->mRecordPacket += inNumPackets;
                     }
        }

        // if we're not stopping, re-enqueue the buffe so that it gets filled again
        if (aqr->IsRunning())
            XThrowIfError(AudioQueueEnqueueBuffer(inAQ, inBuffer, 0, NULL), "AudioQueueEnqueueBuffer failed");
    } catch (CAXException e) {
        char buf[256];
        fprintf(stderr, "Error: %s (%s)\n", e.mOperation, e.FormatError(buf));
    }
}