我正在开发一个需要录制视频的应用程序。 在处理来自图像的面部后，将存储视频帧。
我可以成功录制视频。但音频并没有发挥作用。
我的代码如下。
- (void)setupAVCapture
{
frameRate = 30;
NSError *error = nil;
AVCaptureSession *session = [AVCaptureSession new];
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
[session setSessionPreset:AVCaptureSessionPreset640x480];
else
[session setSessionPreset:AVCaptureSessionPresetPhoto];
// Select a video device, make an input
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
// require( error == nil, bail );
isUsingFrontFacingCamera = NO;
if ( [session canAddInput:deviceInput] )
[session addInput:deviceInput];
// Make a still image output
stillImageOutput = [AVCaptureStillImageOutput new];
[stillImageOutput addObserver:self forKeyPath:@"capturingStillImage" options:NSKeyValueObservingOptionNew context:(__bridge void * _Nullable)(AVCaptureStillImageIsCapturingStillImageContext)];
if ( [session canAddOutput:stillImageOutput] )
[session addOutput:stillImageOutput];
// Make a video data output
videoDataOutput = [AVCaptureVideoDataOutput new];
// we want BGRA, both CoreGraphics and OpenGL work well with 'BGRA'
NSDictionary *rgbOutputSettings = [NSDictionary dictionaryWithObject:
[NSNumber numberWithInt:kCMPixelFormat_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];
[videoDataOutput setVideoSettings:rgbOutputSettings];
[videoDataOutput setAlwaysDiscardsLateVideoFrames:YES]; // discard if the data output queue is blocked (as we process the still image)
// create a serial dispatch queue used for the sample buffer delegate as well as when a still image is captured
// a serial dispatch queue must be used to guarantee that video frames will be delivered in order
// see the header doc for setSampleBufferDelegate:queue: for more information
videoDataOutputQueue = dispatch_queue_create("VideoDataOutputQueue", DISPATCH_QUEUE_SERIAL);
[videoDataOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
if ( [session canAddOutput:videoDataOutput] )
[session addOutput:videoDataOutput];
[[videoDataOutput connectionWithMediaType:AVMediaTypeVideo] setEnabled:NO];
effectiveScale = 1.0;
previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[previewLayer setBackgroundColor:[[UIColor blackColor] CGColor]];
[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspect];
CALayer *rootLayer = [previewView layer];
[rootLayer setMasksToBounds:YES];
[previewLayer setFrame:[rootLayer bounds]];
[rootLayer addSublayer:previewLayer];
/* GC Code : */
// Setup the audio input
AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType: AVMediaTypeAudio];
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error ];
// Setup the audio output
_audioOutput = [[AVCaptureAudioDataOutput alloc] init];
if ([session canAddInput:audioInput])
[session addInput:audioInput];
[session addOutput:_audioOutput];
[_audioOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
/*** END ***/
if (error) {
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:[NSString stringWithFormat:@"Failed with error %d", (int)[error code]]
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:@"Dismiss"
otherButtonTitles:nil];
[alertView show];
// [alertView release];
[self teardownAVCapture];
}
[self setUpVideoCapture];
_capSession = session;
[session startRunning];
}
将音频捕捉设置为以下功能。
#pragma mark - Video Capture
-(void)setUpVideoCapture{
NSError *error = nil;
pathVideoTempFile = [NSTemporaryDirectory() stringByAppendingString:@"test.mov"];
BOOL isexit = [[NSFileManager defaultManager] fileExistsAtPath:pathVideoTempFile isDirectory:NO];
if (isexit)
[[NSFileManager defaultManager] removeItemAtPath:pathVideoTempFile error:nil];
videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:pathVideoTempFile] fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(videoWriter);
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:640], AVVideoWidthKey,
[NSNumber numberWithInt:480], AVVideoHeightKey,
nil];
writerInput = [AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings]; //retain should be removed if ARC
adaptor = [AVAssetWriterInputPixelBufferAdaptor
assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
sourcePixelBufferAttributes:nil];
NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);
[videoWriter addInput:writerInput];
isVideoCaptureStart = false;
// Add the audio input
AudioChannelLayout acl;
bzero( &acl, sizeof(acl));
acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
NSDictionary* audioOutputSettings = nil;
// Both type of audio inputs causes output video file to be corrupted.
if( NO ) {
// should work from iphone 3GS on and from ipod 3rd generation
audioOutputSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatMPEG4AAC ], AVFormatIDKey,
[ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
[ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
[ NSNumber numberWithInt: 64000 ], AVEncoderBitRateKey,
[ NSData dataWithBytes: &acl length: sizeof( acl ) ], AVChannelLayoutKey,
nil];
} else {
// should work on any device requires more space
audioOutputSettings = [ NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatAppleLossless ], AVFormatIDKey,
[ NSNumber numberWithInt: 16 ], AVEncoderBitDepthHintKey,
[ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
[ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
[ NSData dataWithBytes: &acl length: sizeof( acl ) ], AVChannelLayoutKey,
nil ];
}
_audioWriterInput = [AVAssetWriterInput
assetWriterInputWithMediaType: AVMediaTypeAudio
outputSettings: audioOutputSettings ] ;
_audioWriterInput.expectsMediaDataInRealTime = YES;
//[_audioWriterInput addTrackAssociationWithTrackOfInput:writerInput type:AVTrackAssociationTypeTimecode];
if ([videoWriter canAddInput:_audioWriterInput])
[videoWriter addInput:_audioWriterInput];
}
我使用以下代码捕获图像帧和音频。
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
if( captureOutput == _audioOutput) {
[self newAudioSample:sampleBuffer];
}else{
if ([writerInput isReadyForMoreMediaData]) {
UIImage *_myImage = [UIImage imageWithCIImage:mainImage];
UIImage *rotatedImage = [self rotate:_myImage orientation:_myImage.imageOrientation];
rotatedImage = [rotatedImage imageRotatedByDegrees:90.0];
// _myImage = [_myImage imageRotatedByDegrees:90.0];
CVPixelBufferRef pixelBuffer = [self newPixelBufferFromCGImage:rotatedImage.CGImage frameSize:rotatedImage.size];
frameCount += 1;
CMTime frameTime = CMTimeMake(frameCount,frameRate);
if (![adaptor appendPixelBuffer:pixelBuffer withPresentationTime:frameTime]) {
NSError *error = [videoWriter error];
NSLog(@"failed to append sbuf: %@", error);
}
CFRelease(pixelBuffer);
}
}
}
-(void) newAudioSample:(CMSampleBufferRef)sampleBuffer
{
if( isVideoCaptureStart )
{
if( videoWriter.status > AVAssetWriterStatusWriting )
{
NSLog(@"Warning: writer status is %ld", (long)videoWriter.status);
if( videoWriter.status == AVAssetWriterStatusFailed )
NSLog(@"Error: %@", videoWriter.error);
return;
}
if( ![_audioWriterInput appendSampleBuffer:sampleBuffer] )
NSLog(@"Unable to write to audio input");
}
}
录音时没有给我任何错误。但它并没有将音频存储到其中。 请帮帮我！
答案 0 :(得分：1)
最后，我得到了为什么音频没有存储到视频中的解决方案。
我改变了以下方法
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
CMFormatDescriptionRef formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer);
if( captureOutput == _audioOutput) {
if (_audioWriterInput == nil && videoWriter.status == AVAssetWriterStatusUnknown){
[self setupAssetWriterAudioInput:formatDescription];
}else{
[self newAudioSample:sampleBuffer];
}
}else{
if (writerInput == nil && videoWriter.status == AVAssetWriterStatusUnknown){
[self setupAssetWriterVideoInput:formatDescription];
}else{
if (isVideoCaptureStart == true && videoWriter.status == AVAssetWriterStatusUnknown) {
if ([videoWriter startWriting]) {
timeVideoWriteStart = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
[videoWriter startSessionAtSourceTime:timeVideoWriteStart];
}
else {
NSLog(@"AVAssetWriter startWriting error:%@", videoWriter.error);
}
}
}
}
我从当前缓冲时间开始会话。
[videoWriter startSessionAtSourceTime:timeVideoWriteStart];
解决了我的问题。