小编shu*_*aat的帖子

我正在尝试使用AVFoundation录制视频.当我只将视频输入添加到会话时,一切正常,但是当我向其添加音频输入时,它会停止录制视频.(录制开始后立即调用Delegate方法).这是我的代码:

-(void) recordVideo
{    
self.session = [[AVCaptureSession alloc] init];

if([session canSetSessionPreset:AVCaptureSessionPresetMedium])
    session.sessionPreset =  AVCaptureSessionPresetMedium;


CALayer *viewLayer = [self.cameraView layer];

AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

captureVideoPreviewLayer.frame = viewLayer.bounds;

[viewLayer addSublayer:captureVideoPreviewLayer];



self.videoInput = [AVCaptureDeviceInput deviceInputWithDevice:[self frontFacingCameraIfAvailable] error:nil];

self.audioInput = [AVCaptureDeviceInput deviceInputWithDevice:[self audioDevice] error:nil];


if(!videoInput)
    NSLog(@"Couldn't create input!");

else
{
    self.output= [[AVCaptureMovieFileOutput alloc] init];

    NSString *pathString = [[self outputPath]stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSURL *fileURL = [NSURL fileURLWithPath:pathString];


    [session beginConfiguration];

    [session removeInput:[self videoInput]];
    if([session canAddInput:videoInput])
        [session addInput:videoInput];

    [videoInput release];

    [session removeInput:[self audioInput]];
     if([session canAddInput:audioInput])
        [session addInput:audioInput]; …

我试图将视频帧大小更改为方形,即100 x 100.以下是代码:

- (void) changeSize :(NSURL *) url
{

//Create audio/video Settings
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               [NSNumber numberWithInt: 100], AVVideoWidthKey, 
                               [NSNumber numberWithInt:100], AVVideoHeightKey, 
                               nil];

NSDictionary * audioSettings = [NSDictionary dictionaryWithObjectsAndKeys: 
                               [NSNumber numberWithFloat: 44100.0], AVSampleRateKey, 
                               [NSNumber numberWithInt: 2], AVNumberOfChannelsKey, 
                               [NSNumber numberWithInt: kAudioFormatAppleLossless], AVFormatIDKey, 
                               [NSData data], AVChannelLayoutKey, nil];



//Read Asset 
AVURLAsset *myAsset = [AVURLAsset URLAssetWithURL:url options:nil];

NSArray *videoTracks = [myAsset tracksWithMediaType:AVMediaTypeVideo];
AVAssetTrack *audioTrack = [[myAsset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];


AVAssetReader *assetReader = [[AVAssetReader alloc]initWithAsset:myAsset error:nil];

AVAssetReaderOutput *videoOutput = [AVAssetReaderVideoCompositionOutput assetReaderVideoCompositionOutputWithVideoTracks:videoTracks videoSettings:nil]; …