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ideawu/AVFoundation write read audio file frame by frame

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  1. ideawu renamed this gist Mar 3, 2016. 1 changed file with 0 additions and 0 deletions.
    0 .m → ...tion write read audio file frame by frame
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  2. ideawu created this gist Mar 3, 2016.
    205 changes: 205 additions & 0 deletions .m
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,205 @@
    #import <AVFoundation/AVFoundation.h>
    #import "Recorder.h"

    @interface Recorder()<AVCaptureAudioDataOutputSampleBufferDelegate>{
    AVCaptureDevice *audioDevice;
    AVCaptureDeviceInput *audioInput;
    AVCaptureAudioDataOutput* _audioDataOutput;
    dispatch_queue_t _captureQueue;

    AVURLAsset *_asset;
    AVAssetReader *_assetReader;
    AVAssetReaderTrackOutput *_audioOutput;
    AVAssetReaderTrackOutput *_videoOutput;

    AVAssetTrack* audio_track;

    }
    @property (nonatomic, readonly) AVCaptureSession *session;
    @property (nonatomic) AVAssetWriter *writer;
    @property (nonatomic) AVAssetWriterInput *audioWriterInput;
    @property (nonatomic) NSString *filename;
    @property (nonatomic, readonly) int audioFrameCount;
    @end

    @implementation Recorder

    - (id)init{
    self = [super init];
    _filename = [NSTemporaryDirectory() stringByAppendingPathComponent:@"temp.mp4"];
    NSLog(@"filename: %@", _filename);
    [self setupWriter];
    [self setupDevices];
    return self;
    }

    - (void)setupDevices{
    _captureQueue = dispatch_queue_create("capture", DISPATCH_QUEUE_SERIAL);

    NSError *error = nil;
    _session = [[AVCaptureSession alloc] init];

    _audioDataOutput = [[AVCaptureAudioDataOutput alloc] init];
    [_audioDataOutput setSampleBufferDelegate:self queue:_captureQueue];

    audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
    for(AVCaptureDevice *dev in [AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio]){
    if(dev.position == AVCaptureDevicePositionFront){
    audioDevice = dev;
    break;
    }
    }
    audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error];

    [_session setSessionPreset:AVCaptureSessionPresetMedium];
    [_session addOutput:_audioDataOutput];
    [_session addInput:audioInput];
    [_session commitConfiguration];

    [_session startRunning];
    }

    - (void)setupWriter{
    if([[NSFileManager defaultManager] fileExistsAtPath:_filename]){
    [[NSFileManager defaultManager] removeItemAtPath:_filename error:nil];
    }
    NSURL *url = [NSURL fileURLWithPath:_filename];
    _writer = [AVAssetWriter assetWriterWithURL:url fileType:AVFileTypeMPEG4 error:nil];
    NSDictionary* settings;
    AudioChannelLayout acl;
    bzero(&acl, sizeof(acl));
    acl.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;
    settings = @{
    AVFormatIDKey : @(kAudioFormatMPEG4AAC),
    AVSampleRateKey: @(44100),
    AVChannelLayoutKey: [NSData dataWithBytes:&acl length:sizeof(acl)],
    };
    _audioWriterInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeAudio outputSettings:settings];
    _audioWriterInput.expectsMediaDataInRealTime = YES;
    [_writer addInput:_audioWriterInput];

    if(![_writer startWriting]){
    NSLog(@"start writer failed: %@", _writer.error.description);
    }
    }


    #pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate

    - (BOOL)captureOutputShouldProvideSampleAccurateRecordingStart:(AVCaptureOutput *)captureOutput{
    return YES;
    }

    - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
    if(!_audioWriterInput){
    return;
    }
    if (!CMSampleBufferDataIsReady(sampleBuffer)){
    NSLog(@"!CMSampleBufferDataIsReady");
    return;
    }

    double time = CMTimeGetSeconds(CMSampleBufferGetPresentationTimeStamp(sampleBuffer));

    if(_audioFrameCount == 0){
    NSLog(@"start %@", _writer.outputURL.lastPathComponent);
    [_writer startSessionAtSourceTime:CMTimeMakeWithSeconds(time, 1)];
    }
    if (_writer.status == AVAssetWriterStatusFailed){
    NSLog(@"writer error %@", _writer.error.localizedDescription);
    // TODO: set status
    }else if(_audioWriterInput.readyForMoreMediaData == YES){
    int count = (int)CMSampleBufferGetNumSamples(sampleBuffer);
    _audioFrameCount += count;
    [_audioWriterInput appendSampleBuffer:sampleBuffer];

    if(_audioFrameCount > 44100){
    _audioWriterInput = nil;

    [_writer finishWritingWithCompletionHandler:^{
    NSLog(@"stop %@", _writer.outputURL.lastPathComponent);
    if(_writer.status != AVAssetWriterStatusCompleted){
    NSLog(@"asset writer failed: %@", _writer.outputURL.lastPathComponent);
    return;
    }
    NSLog(@"finish writting %d samples", _audioFrameCount);

    [self readAudioFile];
    }];
    }
    }else{
    NSLog(@"!readyForMoreMediaData %d", (int)_writer.status);
    }
    }


    - (void)readAudioFile{
    NSError *error;
    _asset = [AVURLAsset URLAssetWithURL:_writer.outputURL options:nil];
    _assetReader = [[AVAssetReader alloc] initWithAsset:_asset error:&error];

    NSDictionary *settings;
    audio_track = [_asset tracksWithMediaType:AVMediaTypeAudio].lastObject;
    if(audio_track){
    settings = @{
    AVFormatIDKey: @(kAudioFormatLinearPCM),
    };
    _audioOutput = [[AVAssetReaderTrackOutput alloc] initWithTrack:audio_track
    outputSettings:settings];
    if([_assetReader canAddOutput:_audioOutput]){
    [_assetReader addOutput:_audioOutput];
    }
    }
    [_assetReader startReading];

    AudioFileID fileID = nil;
    OSStatus err=noErr;
    err = AudioFileOpenURL( (__bridge CFURLRef) _writer.outputURL, kAudioFileReadPermission, 0, &fileID );
    if( err != noErr ) {
    NSLog( @"AudioFileOpenURL failed" );
    }

    AudioFilePacketTableInfo _audioInfo;
    UInt32 size = sizeof(_audioInfo);
    AudioFileGetProperty(fileID, kAudioFilePropertyPacketTableInfo, &size, &_audioInfo);
    NSLog(@"priming: %d remainder: %d valid: %d", _audioInfo.mPrimingFrames, _audioInfo.mRemainderFrames, (int)_audioInfo.mNumberValidFrames);

    AudioFileClose(fileID);

    int total_samples = 0;
    NSMutableData *data = [[NSMutableData alloc] init];
    while(1){
    CMSampleBufferRef sampleBuffer = [_audioOutput copyNextSampleBuffer];
    if(!sampleBuffer){
    break;
    }

    OSStatus err;
    AudioBufferList audioBufferList;
    CMBlockBufferRef blockBuffer = CMSampleBufferGetDataBuffer(sampleBuffer);
    err = CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(
    sampleBuffer,
    NULL,
    &audioBufferList,
    sizeof(AudioBufferList),
    NULL,
    NULL,
    kCMSampleBufferFlag_AudioBufferList_Assure16ByteAlignment,
    &blockBuffer
    );
    for (NSUInteger i = 0; i < audioBufferList.mNumberBuffers; i++) {
    AudioBuffer audioBuffer = audioBufferList.mBuffers[i];
    [data appendBytes:audioBuffer.mData length:audioBuffer.mDataByteSize];
    }

    CMItemCount numSamplesInBuffer = CMSampleBufferGetNumSamples(sampleBuffer);
    total_samples += numSamplesInBuffer;

    CFRelease(blockBuffer);
    CFRelease(sampleBuffer);
    }
    NSLog(@"read %d samples", total_samples);
    }


    @end