。

要执行实时音视频采集#xff0c;需要实例化采集会话并添加适当的输入和输出。

AVCaptureSession#xff1a;管理输入输出音视频流AVCaptureDevice#xff1a;相机硬件的接口#xff0c;用于控制硬件特性…AVCaptureSession配置采集行为并协调从输入设备到采集输出的数据流。

要执行实时音视频采集需要实例化采集会话并添加适当的输入和输出。

AVCaptureSession管理输入输出音视频流AVCaptureDevice相机硬件的接口用于控制硬件特性诸如镜头的位置(前后摄像头)、曝光、闪光灯等。

AVCaptureInput配置输入设备提供来自设备的数据AVCaptureOutput管理输出的音视频数据流AVCaptureConnection输入与输出的连接AVCaptureVideoPreviewLayer显示当前相机正在采集的状况AVAssetWriter将媒体数据写入到容器文件

初始化AVCaptureSession

canSetSessionPreset:AVCaptureSessionPresetHigh])

AVCaptureSessionPreset1280x720;}}return

_captureSession;

dispatch_queue_create(VideoCapture,

_videoQueue;

*)getCameraDeviceWithPosition:(AVCaptureDevicePosition

)position

{AVCaptureDeviceDiscoverySession

[AVCaptureDeviceDiscoverySession

discoverySessionWithDeviceTypes:[AVCaptureDeviceTypeBuiltInWideAngleCamera]

(AVCaptureDevice

deviceDiscoverySession.devices)

{if

getCameraDeviceWithPosition:AVCaptureDevicePositionBack];if

(!captureDevice){NSLog(captureDevice

*error

defaultDeviceWithMediaType:AVMediaTypeAudio];NSError

*error

init];self.videoOutput.alwaysDiscardsLateVideoFrames

canAddOutput:self.videoOutput])

}添加音频输出

canAddOutput:self.audioOutput])

设置视频预览

(void)setupCaptureVideoPreviewLayer:(UIView

*)previewView

initWithSession:self.captureSession];CALayer

*layer

previewView.layer;_captureVideoPreviewLayer.frame

previewView.bounds;_captureVideoPreviewLayer.videoGravity

AVLayerVideoGravityResizeAspect;_captureVideoPreviewLayer.videoGravity

AVLayerVideoGravityResizeAspectFill;_captureVideoPreviewLayer.connection.videoOrientation

AVCaptureVideoOrientationLandscapeRight;[layer

insertSublayer:_captureVideoPreviewLayer

atIndex:0];

assetWriterWithURL:self.videoURL

error:nil];NSInteger

(bitsPerSecond),AVVideoExpectedSourceFrameRateKey

(15),AVVideoMaxKeyFrameIntervalKey

AVVideoProfileLevelH264BaselineAutoLevel

};self.videoCompressionSettings

AVVideoCodecKey

AVVideoCodecTypeH264,AVVideoWidthKey

(width

AVVideoScalingModeResizeAspect,AVVideoCompressionPropertiesKey

[AVAssetWriterInput

assetWriterInputWithMediaType:AVMediaTypeVideo

outputSettings:self.videoCompressionSettings];_assetWriterVideoInput.expectsMediaDataInRealTime

YES;self.audioCompressionSettings

(kAudioFormatMPEG4AAC),AVNumberOfChannelsKey

(1),AVSampleRateKey

assetWriterInputWithMediaType:AVMediaTypeAudio

outputSettings:self.audioCompressionSettings];_assetWriterAudioInput.expectsMediaDataInRealTime

YES;if

canAddInput:_assetWriterVideoInput]){[_assetWriter

addInput:_assetWriterVideoInput];}else{NSLog(AssetWriter

videoInput

canAddInput:_assetWriterAudioInput]){[_assetWriter

addInput:_assetWriterAudioInput];}else{NSLog(AssetWriter

audioInput

AVCaptureVideoDataOutputSampleBufferDelegate和AVCaptureAudioDataOutputSampleBufferDelegate音视频处理

#pragma

AVCaptureVideoDataOutputSampleBufferDelegate|AVCaptureAudioDataOutputSampleBufferDelegate

(void)captureOutput:(AVCaptureOutput

*)captureOutput

didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer

fromConnection:(AVCaptureConnection

*)connection

connectionWithMediaType:AVMediaTypeVideo])

appendSampleBuffer:sampleBuffer

ofMediaType:AVMediaTypeVideo];}}if

(connection

connectionWithMediaType:AVMediaTypeAudio])

{synchronized(self)

appendSampleBuffer:sampleBuffer

ofMediaType:AVMediaTypeAudio];}}}

(void)appendSampleBuffer:(CMSampleBufferRef)sampleBuffer

*)mediaType

sampleBuffer);return;}autoreleasepool{if

(!self.canWrite

AVMediaTypeVideo){[self.assetWriter

startWriting];[self.assetWriter

startSessionAtSourceTime:CMSampleBufferGetPresentationTimeStamp(sampleBuffer)];self.canWrite

YES;}if

(self.assetWriterVideoInput.readyForMoreMediaData){BOOL

success

appendSampleBuffer:sampleBuffer];if

(!success){NSLog(assetWriterVideoInput

appendSampleBuffer

(self.assetWriterAudioInput.readyForMoreMediaData){BOOL

success

appendSampleBuffer:sampleBuffer];if

(!success){NSLog(assetWriterAudioInput

appendSampleBuffer

finishWritingWithCompletionHandler:^{weakSelf.canWrite

nil;weakSelf.assetWriterAudioInput

nil;weakSelf.assetWriterVideoInput

nil;}];}