话不多说首先上效果图
WechatIMG7.png
原理：
屏幕的左半部分为
AVCaptureVideoPreviewLayer而右半部分则为
UIImageView
代码
遵循<AVCaptureVideoDataOutputSampleBufferDelegate>协议
//捕获设备，通常是前置摄像头，后置摄像头，麦克风（音频输入）
@property (nonatomic, strong) AVCaptureDevice *device;
//AVCaptureDeviceInput 代表输入设备，他使用AVCaptureDevice 来初始化
@property (nonatomic, strong) AVCaptureDeviceInput *input;
//输出图片
@property (nonatomic ,strong) AVCaptureVideoDataOutput *imageOutput;
//session：由他把输入输出结合在一起，并开始启动捕获设备（摄像头）
@property (nonatomic, strong) AVCaptureSession *session;
//图像预览层，实时显示捕获的图像
@property (nonatomic ,strong) AVCaptureVideoPreviewLayer *previewLayer;
@property (strong, nonatomic) UIImageView *outputImageView;
@property (strong, nonatomic) UIView *leftView;
- (void)cameraDistrict
{
// AVCaptureDevicePositionBack 后置摄像头
// AVCaptureDevicePositionFront 前置摄像头
self.device = [self cameraWithPosition:AVCaptureDevicePositionBack];
self.input = [[AVCaptureDeviceInput alloc] initWithDevice:self.device error:nil];
self.imageOutput = [[AVCaptureVideoDataOutput alloc]init];
self.imageOutput.alwaysDiscardsLateVideoFrames = YES;
dispatch_queue_t queue;
queue = dispatch_queue_create("cameraQueue", NULL);
[self.imageOutput setSampleBufferDelegate:self queue:queue];
NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;
NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];
NSDictionary* videoSettings = [NSDictionary dictionaryWithObject:value forKey:key];
[self.imageOutput setVideoSettings:videoSettings];
self.session = [[AVCaptureSession alloc] init];
// 拿到的图像的大小可以自行设定
// AVCaptureSessionPreset320x240
// AVCaptureSessionPreset352x288
// AVCaptureSessionPreset640x480
// AVCaptureSessionPreset960x540
// AVCaptureSessionPreset1280x720
// AVCaptureSessionPreset1920x1080
// AVCaptureSessionPreset3840x2160
self.session.sessionPreset = AVCaptureSessionPreset640x480;
//输入输出设备结合
if ([self.session canAddInput:self.input]) {
[self.session addInput:self.input];
}
if ([self.session canAddOutput:self.imageOutput]) {
[self.session addOutput:self.imageOutput];
}
//预览层的生成
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
self.previewLayer.frame = self.leftView.bounds;
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[[self.previewLayer connection]setVideoOrientation:AVCaptureVideoOrientationLandscapeRight];
[self.leftView.layer addSublayer:self.previewLayer];
_outputImageView = [[UIImageView alloc]init];
_outputImageView.contentMode = UIViewContentModeScaleAspectFill;
_outputImageView.clipsToBounds = YES;
[self.view addSubview:_outputImageView];
_outputImageView.sd_layout
.leftSpaceToView(self.leftView, 0)
.rightSpaceToView(self.view, 0)
.topSpaceToView(self.view, 0)
.bottomSpaceToView(self.view, 0);
//设备取景开始
[self.session startRunning];
if ([_device lockForConfiguration:nil]) {
//自动闪光灯，
if ([_device isFlashModeSupported:AVCaptureFlashModeAuto]) {
[_device setFlashMode:AVCaptureFlashModeAuto];
}
//自动白平衡,但是好像一直都进不去
if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) {
[_device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];
}
[_device unlockForConfiguration];
}
}
- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position{
NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for ( AVCaptureDevice *device in devices )
if ( device.position == position ){
return device;
}
return nil;
}
- (AVCaptureVideoOrientation) videoOrientationFromCurrentDeviceOrientation {
switch (self.interfaceOrientation) {
case UIInterfaceOrientationPortrait: {
return AVCaptureVideoOrientationPortrait;
}
case UIInterfaceOrientationLandscapeLeft: {
return AVCaptureVideoOrientationLandscapeLeft;
}
case UIInterfaceOrientationLandscapeRight: {
return AVCaptureVideoOrientationLandscapeRight;
}
case UIInterfaceOrientationPortraitUpsideDown: {
return AVCaptureVideoOrientationPortraitUpsideDown;
}
case UIInterfaceOrientationUnknown: {
break;
}
}
return AVCaptureVideoOrientationLandscapeLeft;
}
#pragma mark AVCaptureSession delegate
/**
将sampleBuffer转换成image并绘制在右侧ImageView上
*/
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer,0);
uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef newContext = CGBitmapContextCreate(baseAddress,width, height, 8, bytesPerRow, colorSpace,kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGImageRef newImage = CGBitmapContextCreateImage(newContext);
CGContextRelease(newContext);
CGColorSpaceRelease(colorSpace);
UIImage *image= [UIImage imageWithCGImage:newImage scale:1.0 orientation:UIImageOrientationUp];
CGImageRelease(newImage);
[_outputImageView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:YES];
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
}
隐藏系统的音量调节窗口
AVAudioSession *audio = [AVAudioSession sharedInstance];
[audio setActive:YES error:nil];
MPVolumeView *volumeView = [[MPVolumeView alloc]initWithFrame:CGRectMake(-2000, -2000, 10, 10)];
volumeView.hidden = NO;
[self.view addSubview:volumeView];
监听系统音量调节事件
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(volumeClicked:) name:@"AVSystemController_SystemVolumeDidChangeNotification" object:nil];
// 但是仅仅监听是不起作用的，因为@"AVSystemController_SystemVolumeDidChangeNotification"需要对它进行响应，所以要在监听后加
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
根据音量加减来调节相机焦距
-(void)volumeClicked:(NSNotification *)noti{
//1.0~67.5
CGFloat zoom = self.device.videoZoomFactor;
NSLog(@"%.f",zoom);
NSDictionary *userInfo = [noti userInfo];
CGFloat volume = [[userInfo valueForKey:@"AVSystemController_AudioVolumeNotificationParameter"]floatValue];
if (volume == 1.0 && self.volume == 1.0) {//增加到最大了
zoom += 0.25;
}else if (volume == 0.0 && self.volume == 0.0)//减小到最小了
{
zoom -= 0.25;
}else if(volume > self.volume)//++
{
zoom += 0.25;
self.volume = volume;
}else if (volume < self.volume)//--
{
self.volume = volume;
zoom -= 0.25;
}
NSError *error = nil;
if (zoom < 1 || zoom > 30) {
return;
}
[self.device lockForConfiguration:&error];
if (!error) {
self.device.videoZoomFactor = zoom;
}else
{
NSLog(@"error = %@", error);
}
[self.device unlockForConfiguration];
}
