AVCaptureSession是AVFoundation的核心类,用于捕捉视频和音频,协调视频和音频的输入和输出流.
- 输入源
设备AVCaptureDevice
[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] - 输出源
添加AVCaptureOutput,即AVCaptureSession的输出源.一般输出源分成:音视频源,图片源,文件源等.
音视频输出AVCaptureAudioDataOutput,AVCaptureVideoDataOutput.
静态图片输出AVCaptureStillImageOutput(iOS10中被AVCapturePhotoOutput取代了)
AVCaptureMovieFileOutput表示文件源.
创建会话AVCaptureSession
-(AVCaptureSession *)captureSession{
if (!_captureSession) {
_captureSession = [[AVCaptureSession alloc]init];
if ([[UIDevice currentDevice]userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
customLog(@"当前使用的是手机");
}
}
return _captureSession;
}
创建输入源
1、创建AVCaptureDevice
-(AVCaptureDevice *)getCaptureDevice{
// 每次获取都要重新创建
NSArray * devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice * device in devices) {
if (device.position == self.captureDevicePosition) {
NSError * error = nil;
if ([device lockForConfiguration:&error]) {
// 焦点 曝光 黑白色 -> 自动
if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
}
if ([device isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {
device.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
}
if ([device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance]) {
device.whiteBalanceMode = AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance;
}
[device unlockForConfiguration];
}
_captureDevice = device;
return _captureDevice;
}
}
return nil;
}
2、创建AVCaptureDeviceInput
-(AVCaptureDeviceInput *)getCaptureDeviceInput{
NSError * error = nil;
AVCaptureDevice * device = [self getCaptureDevice];
_captureDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (error || device == nil) {
NSLog(@"创建失败: %@",error.description);
}
return _captureDeviceInput;
}
3、添加输入源到会话中
AVCaptureSession * session = self.captureSession;
// 添加输入对象到会话
if ([session.inputs containsObject:self.captureDeviceInput]) {
[session removeInput:self.captureDeviceInput];
}
AVCaptureDeviceInput * input = [self getCaptureDeviceInput];
if ([session canAddInput:input]) {
[session addInput:input];
}
创建输出源并添加到会话中
// 添加照片输出
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"10.0")) {
AVCapturePhotoOutput * photoOutput = [[AVCapturePhotoOutput alloc]init];
// 先移除
if ([session.outputs containsObject:self.captureOutput]) {
[session removeOutput:self.captureOutput];
}
// 添加
if ([session canAddOutput:photoOutput]) {
[session addOutput:photoOutput];
}
self.captureOutput = photoOutput;
}else{
AVCaptureStillImageOutput * stillImageOutput = [[AVCaptureStillImageOutput alloc]init];
NSDictionary *myOutputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey,nil];
[stillImageOutput setOutputSettings:myOutputSettings];
// 先移除
if ([session.outputs containsObject:self.captureOutput]) {
[session removeOutput:self.captureOutput];
}
// 添加
if ([session canAddOutput:stillImageOutput]){
[session addOutput:stillImageOutput];
}
self.captureOutput = stillImageOutput;
}
输出对象-视频流对象作为输出适合及时获取输出数据(直播)
AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
[videoDataOutput setAlwaysDiscardsLateVideoFrames:YES];// 默认为YES
// 设置代理，捕获视频样品数据
// 注意：队列必须是串行队列，才能获取到数据，而且不能为空
dispatch_queue_t photoCaptureQueue = dispatch_queue_create(MDPhotoCaptureQueue, DISPATCH_QUEUE_SERIAL);
[videoDataOutput setSampleBufferDelegate:self queue:photoCaptureQueue];
if ([session canAddOutput:videoDataOutput]) {
[session addOutput:videoDataOutput];
}
#pragma mark AVCaptureVideoDataOutputSampleBufferDelegate
- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
- // 及时获取视频输出数据
customLog(@"采集到数据");
}
添加预览图层
-(void)addPreviewLayer{
// 视频预览图层
AVCaptureVideoPreviewLayer *previedLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.captureSession];
previedLayer.frame = [UIScreen mainScreen].bounds;
_previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.view.layer insertSublayer:previedLayer atIndex:0];
_previewLayer = previedLayer;
}
切换前后置摄像头-切换输入源
- (void)changeInput{
// 移除输入对象
if (self.captureDeviceInput && [self.captureSession.inputs containsObject:self.captureDeviceInput]) {
[self.captureSession removeInput:self.captureDeviceInput];
}
// 添加输入对象到会话
AVCaptureDeviceInput * input = [self getCaptureDeviceInput];
if ([self.captureSession canAddInput:input]) {
[self.captureSession addInput:input];
}
self.isChangeCaptureDevicePostion = NO;
// 给摄像头的切换添加翻转动画
CATransition *animation = [CATransition animation];
animation.duration = .5f;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
animation.type = @"oglFlip";
if (self.captureDevicePosition == AVCaptureDevicePositionFront) {
animation.subtype = kCATransitionFromLeft;
}else{
animation.subtype = kCATransitionFromRight;
}
[self.previewLayer addAnimation:animation forKey:nil];
}
拍照按钮点击-获取图片
-(void)commitButtonAction{
// 拍照
if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"10.0")) {
AVCapturePhotoOutput * output = (AVCapturePhotoOutput *)self.captureOutput;
//从 AVCaptureStillImageOutput 中取得 AVCaptureConnection
self.captureConnection = [output connectionWithMediaType:AVMediaTypeVideo];
AVCapturePhotoSettings * settings = [AVCapturePhotoSettings photoSettings];
[output capturePhotoWithSettings:settings delegate:self];
}else{
AVCaptureStillImageOutput * stillImageOutput = (AVCaptureStillImageOutput *)self.captureOutput;
//从 AVCaptureStillImageOutput 中取得 AVCaptureConnection
self.captureConnection = [stillImageOutput connectionWithMediaType:AVMediaTypeVideo];
[stillImageOutput captureStillImageAsynchronouslyFromConnection:self.captureConnection completionHandler:^(CMSampleBufferRef _Nullable imageDataSampleBuffer, NSError * _Nullable error) {
if (imageDataSampleBuffer != nil) {
NSData * data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
// 取得静态影像 两种获取方式
//UIImage * image = [[UIImage alloc]initWithData:data];
CFDataRef cfData = CFBridgingRetain(data);
CGDataProviderRef dataProvider = CGDataProviderCreateWithCFData(cfData);
CGImageRef cgImage = CGImageCreateWithJPEGDataProvider(dataProvider, nil, YES, kCGRenderingIntentDefault);
CFBridgingRelease(cfData);
// 裁剪图片
[self cropWithImage:[UIImage imageWithCGImage:cgImage]];
// 取得影像数据（需要ImageIO.framework 与 CoreMedia.framework）
CFDictionaryRef attachments = CMGetAttachment(imageDataSampleBuffer, kCGImagePropertyExifDictionary, NULL);
customLog(@"影像属性: %@", attachments);
}
}];
}
}
代理获取图片AVCapturePhotoOutput
#pragma mark AVCapturePhotoCaptureDelegate
// IOS - 11
- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhoto:(AVCapturePhoto *)photo error:(NSError *)error{
if (error) {
customLog(@"获取图片错误 --- %@",error.localizedDescription);
}
if (photo) {
if (@available(iOS 11.0, *)) {
CGImageRef cgImage = [photo CGImageRepresentation];
UIImage * image = [UIImage imageWithCGImage:cgImage];
customLog(@"获取图片成功 --- %@",image);
} else {
customLog(@"不是走这个代理方法");
}
}
}
- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhotoSampleBuffer:(nullable CMSampleBufferRef)photoSampleBuffer previewPhotoSampleBuffer:(nullable CMSampleBufferRef)previewPhotoSampleBuffer resolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings bracketSettings:(nullable AVCaptureBracketedStillImageSettings *)bracketSettings error:(nullable NSError *)error{
if (error) {
customLog(@"获取图片错误 --- %@",error.localizedDescription);
}
if (photoSampleBuffer) {
NSData *data = [AVCapturePhotoOutput JPEGPhotoDataRepresentationForJPEGSampleBuffer:photoSampleBuffer previewPhotoSampleBuffer:previewPhotoSampleBuffer];
UIImage *image = [UIImage imageWithData:data];
customLog(@"获取图片成功 --- %@",image);
}
}