iOS 自定义相机, UIImagePickerController && AVCaptureSession (附微信小视频模仿demo)

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iOS 自定义相机, UIImagePickerController && AVCaptureSession (附微信小视频模仿demo)

序

今天介绍自定义相机的两种方式,一种是UIImagePickerController,一种是AVCaptureSession.

UIImagePickerController

UIImagePickerController非常方便简单,是苹果自己封装好了的一套API,效果如下:

AVCaptureSession

但是上面的 API只能进行简单的相机视图修改,有时无法满足我们的需求.例如我们需要更加复杂的OverlayerView(自定义相机视图)，这时候我们就要自定义一个相机了.AVCaptureSession能帮助我们.

code

心急的人,完整Demo在最下边儿.其他朋友可依次看下去

UIImagePickerController

属性

首先看到,需要遵守的协议有2个,分别是UINavigationControllerDelegate和UIImagePickerControllerDelegate

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@property(nullable,nonatomic,weak)      id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;	//需要遵守的协议有2个

还有一些基本设置,如输入源/媒体类型,还有allowsEditing为 YES 即可允许用户拍照后立即进行编辑,并且出现编辑框

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//基本设置
@property(nonatomic)           UIImagePickerControllerSourceType     sourceType;			//图片输入源,相机或者相册,图库
@property(nonatomic,copy)      NSArray<NSString *>                   *mediaTypes;			//媒体类型
@property(nonatomic)           BOOL                                  allowsEditing 			//是否允许用户编辑
@property(nonatomic)           BOOL                                  allowsImageEditing 	//废弃,用上面的即可

这2个属性和视频相关

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@property(nonatomic)           NSTimeInterval                        videoMaximumDuration 	//最长摄制时间
@property(nonatomic)           UIImagePickerControllerQualityType    videoQuality 			//视频摄制质量

这2个和自定义相机视图有关,注意,下面的只有当输入源为UIImagePickerControllerSourceTypeCamera才可用,否则崩溃

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@property(nonatomic)           BOOL                                  showsCameraControls 	//默认 YES, 设置为 NO 即可关闭所有默认 UI
@property(nullable, nonatomic,strong) __kindof UIView                *cameraOverlayView  	//自定义相机覆盖视图
@property(nonatomic)           CGAffineTransform                     cameraViewTransform 	//拍摄时屏幕view的transform属性，可以实现旋转，缩放功能
@property(nonatomic) UIImagePickerControllerCameraCaptureMode cameraCaptureMode 			//设置模式为拍照或者摄像
@property(nonatomic) UIImagePickerControllerCameraDevice      cameraDevice      			//默认开启前置/后置摄像头
@property(nonatomic) UIImagePickerControllerCameraFlashMode   cameraFlashMode				//设置默认的闪光灯模式,有开/关/自动

方法

第一个是判断输入源的,一般用来判断是否支持拍照

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typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
    UIImagePickerControllerSourceTypePhotoLibrary,		//图库
    UIImagePickerControllerSourceTypeCamera,			//相机-->这个就是拍照
    UIImagePickerControllerSourceTypeSavedPhotosAlbum	//相册
};
+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType;      		//判断是否支持某种输入源

这个是判断是否支持前/后置摄像头

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typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {
    UIImagePickerControllerCameraDeviceRear,			//后置
    UIImagePickerControllerCameraDeviceFront			//前置
};
+ (BOOL)isCameraDeviceAvailable:(UIImagePickerControllerCameraDevice)cameraDevice     //是否支持前/后置摄像头

拍照/摄像的方法

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- (void)takePicture;		//手动调取拍照的方法,也可当做`-imagePickerController:didFinishPickingMediaWithInfo:`代理的回调,无法捕捉动态图像
- (BOOL)startVideoCapture;	//开始摄像
- (void)stopVideoCapture;	//停止摄像

代理相关

注意,UIImagePickerController不能直接取消,必须在收到以下代理方法后才可以 dismiss

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@protocol UIImagePickerControllerDelegate<NSObject>
@optional
//这个已经废弃了,不用管
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo;
//主要是下面这2个
//拍照后,点击使用照片和向此选取照片后都会调用以下代理方法
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info;
//点击取消的时候会调用,通常在此 dismiss 
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;
@end

保存照片/视频到手机,三个比较重要的方法,记得导入AssetsLibrary.framework,并且在需要调用存储方法的的地方导入<AssetsLibrary/AssetsLibrary.h>

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// 将照片保存到相册,回调方法必须用 - (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;
UIKIT_EXTERN void UIImageWriteToSavedPhotosAlbum(UIImage *image, __nullable id completionTarget, __nullable SEL completionSelector, void * __nullable contextInfo);
//是否可以将视频保存到相册,通常在调用下面的方法之前会调用这个
UIKIT_EXTERN BOOL UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(NSString *videoPath) NS_AVAILABLE_IOS(3_1);
// 将视频保存到相册,回调方法必须用 - (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo; 
UIKIT_EXTERN void UISaveVideoAtPathToSavedPhotosAlbum(NSString *videoPath, __nullable id completionTarget, __nullable SEL completionSelector, void * __nullable contextInfo) NS_AVAILABLE_IOS(3_1);

用法如下

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- (void)savePic
{
    UIImageWriteToSavedPhotosAlbum(imgPath, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);    
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{
    
    if (error) {
        NSLog(@"保存照片过程中发生错误，错误信息:%@",error.localizedDescription);
    }else{
        NSLog(@"照片保存成功.");
    }
}
- (void)saveVideo
{
    UISaveVideoAtPathToSavedPhotosAlbum(videoPath,self, @selector(video:didFinishSavingWithError:contextInfo:), nil);//保存视频到相簿    
}
- (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    if (error) {
        NSLog(@"保存视频过程中发生错误，错误信息:%@",error.localizedDescription);
    }else{
        NSLog(@"视频保存成功.");
    }
}

另外一个是ALAssetsLibrary,不过在 iOS9.0 已经全部被废弃了,改成了PHPhotoLibrary(这是 Photos 框架的一个组成部分,完整的可以点这个链接,关于这个框架的用法,改天再写一个吧)

9.0及以前的写法

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//保存照片到相册
 [[[ALAssetsLibrary alloc]init] writeImageToSavedPhotosAlbum:[img CGImage] orientation:(ALAssetOrientation)img.imageOrientation completionBlock:^(NSURL *assetURL, NSError *error) {
    if (error) {
        NSLog(@"Save image fail：%@",error);
    }else{
        NSLog(@"Save image succeed.");
    }
}];
//保存视频到相册
[[[ALAssetsLibrary alloc]init] writeVideoAtPathToSavedPhotosAlbum:[NSURL URLWithString:videoPath] completionBlock:^(NSURL *assetURL, NSError *error) {
       
    if (error) {
        NSLog(@"Save video fail：%@",error);
    }else{
        NSLog(@"Save video succeed.");
    }
    
}];

AVCaptureSession

先放上一个微信小视频的模仿 Demo, 因为只能真机,所以比较嘈杂~大家别介意

流程

AVCaptureSession通过把设备的麦克风/摄像头(AVCaptureDevice)实例化成数据流输入对象(AVCaptureDeviceInput)后,再通过建立连接(AVCaptionConnection)将录制数据通过数据流输出对象(AVCaptureOutput)导出,而录制的时候咱们可以同步预览当前的录制界面(AVCaptureVideoPreviewLayer).

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`AVCaptureSession`是一个会话对象,是设备音频/视频整个录制期间的管理者.
`AVCaptureDevice`其实是咱们的物理设备映射到程序中的一个对象.咱们可以通过其来操作:闪光灯,手电筒,聚焦模式等
`AVCaptureDeviceInput`是录制期间输入流数据的管理对象.
`AVCaptionConnection`是将输入流/输出流连接起来的连接对象,视频/音频稳定,预览与录制方向一致都在这里设置,还有audioChannels声道
`AVCaptureOutput`是输出流数据的管理对象,通过头文件可以看到有很多子类,而我们通常也使用其子类
`AVCaptureVideoPreviewLayer`是一个 `CALyer` ,可以让我们预览拍摄过程中的图像

详解各部分

此处,咱们就模仿一个微信小视频的 demo, 然后把各个主要步骤写在下面.

授权

首先获取授权AVAuthorizationStatus,我们需要获取哪个设备的使用权限,就进行请求,需要注意的是,如果用户未进行授权授权选择,咱们还要重复请求一次.

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//获取授权
- (void)getAuthorization
{
    
    //此处获取摄像头授权
    switch ([AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo])
    {
        case AVAuthorizationStatusAuthorized:       //已授权，可使用    The client is authorized to access the hardware supporting a media type.
        {
            break;
        }
        case AVAuthorizationStatusNotDetermined:    //未进行授权选择     Indicates that the user has not yet made a choice regarding whether the client can access the hardware.
        {
            //则再次请求授权
            [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
                if(granted){    //用户授权成功
                    return;
                } else {        //用户拒绝授权
                    return;
                }
            }];
            break;
        }
        default:                                    //用户拒绝授权/未授权
        {
            break;
        }
    }
}

相关枚举

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/*
     AVAuthorizationStatusNotDetermined = 0,// 未进行授权选择
     
     AVAuthorizationStatusRestricted,　　　　// 未授权，且用户无法更新，如家长控制情况下
     
     AVAuthorizationStatusDenied,　　　　　　 // 用户拒绝App使用
     
     AVAuthorizationStatusAuthorized,　　　　// 已授权，可使用
     */

根据流程创建对象

AVCaptureSession

先创建本次小视频的会话对象_captureSession,设置视频分辨率.注意,这个地方设置的模式/分辨率大小将影响你后面拍摄照片/视频的大小

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- (void)addSession
{
    _captureSession = [[AVCaptureSession alloc] init];
    
    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset640x480]) {
        [_captureSession setSessionPreset:AVCaptureSessionPreset640x480];
    }
}

相关枚举

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/*  通常支持如下格式
 (
 AVAssetExportPresetLowQuality,
 AVAssetExportPreset960x540,
 AVAssetExportPreset640x480,
 AVAssetExportPresetMediumQuality,
 AVAssetExportPreset1920x1080,
 AVAssetExportPreset1280x720,
 AVAssetExportPresetHighestQuality,
 AVAssetExportPresetAppleM4A
 )
 */
AVCaptureDevice

然后咱们要把设备接入进来了,依次是_videoDevice和_audioDevice,还有注意,在给会话信息添加设备对象的时候,需要调用_captureSession的一个方法组beginConfiguration和commitConfiguration,最后,咱们把录制过程中的预览图层PreviewLayer也添加进来,设置完毕后,开启会话startRunning–>注意,不等于开始录制,在不再需要使用会话相关时,还需要stopRunning

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[_captureSession beginConfiguration];
[self addVideo];
[self addAudio];
[self addPreviewLayer];
    
[_captureSession commitConfiguration];
[_captureSession startRunning];
video 相关
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- (void)addVideo
{
    
    // 获取摄像头输入设备， 创建 AVCaptureDeviceInput 对象
    _videoDevice = [self deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack];
    
    [self addVideoInput];
    [self addMovieOutput];
}

相关枚举

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/* MediaType
     AVF_EXPORT NSString *const AVMediaTypeVideo                 NS_AVAILABLE(10_7, 4_0);       //视频
     AVF_EXPORT NSString *const AVMediaTypeAudio                 NS_AVAILABLE(10_7, 4_0);       //音频
     AVF_EXPORT NSString *const AVMediaTypeText                  NS_AVAILABLE(10_7, 4_0);
     AVF_EXPORT NSString *const AVMediaTypeClosedCaption         NS_AVAILABLE(10_7, 4_0);
     AVF_EXPORT NSString *const AVMediaTypeSubtitle              NS_AVAILABLE(10_7, 4_0);
     AVF_EXPORT NSString *const AVMediaTypeTimecode              NS_AVAILABLE(10_7, 4_0);
     AVF_EXPORT NSString *const AVMediaTypeMetadata              NS_AVAILABLE(10_8, 6_0);
     AVF_EXPORT NSString *const AVMediaTypeMuxed                 NS_AVAILABLE(10_7, 4_0);
     */
    
    /* AVCaptureDevicePosition
     typedef NS_ENUM(NSInteger, AVCaptureDevicePosition) {
     AVCaptureDevicePositionUnspecified         = 0,
     AVCaptureDevicePositionBack                = 1,            //后置摄像头
     AVCaptureDevicePositionFront               = 2             //前置摄像头
     } NS_AVAILABLE(10_7, 4_0) __TVOS_PROHIBITED;
     */

下面是获取摄像头的方法

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#pragma mark 获取摄像头-->前/后
- (AVCaptureDevice *)deviceWithMediaType:(NSString *)mediaType preferringPosition:(AVCaptureDevicePosition)position
{
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:mediaType];
    AVCaptureDevice *captureDevice = devices.firstObject;
    for ( AVCaptureDevice *device in devices ) {
        if ( device.position == position ) {
            captureDevice = device;
            break;
        }
    }
    
    return captureDevice;
}
//下面这2个也可以获取前后摄像头,不过有一定的风险,假如手机又问题,找不到对应的 UniqueID 设备,则呵呵了
//- (AVCaptureDevice *)frontCamera
//{
//    return [AVCaptureDevice deviceWithUniqueID:@"com.apple.avfoundation.avcapturedevice.built-in_video:1"];
//}
//
//- (AVCaptureDevice *)backCamera
//{
//    return [AVCaptureDevice deviceWithUniqueID:@"com.apple.avfoundation.avcapturedevice.built-in_video:0"];
//}

添加视频输入对象AVCaptureDeviceInput,根据输入设备初始化输入对象，用户获取输入数据,将视频输入对象添加到会话 (AVCaptureSession) 中

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- (void)addVideoInput
{
    NSError *videoError;
    _videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:_videoDevice error:&videoError];
    if (videoError) {
        NSLog(@"---- 取得摄像头设备时出错 ------ %@",videoError);
        return;
    }
    
    if ([_captureSession canAddInput:_videoInput]) {
        [_captureSession addInput:_videoInput];
    }
}

接下来是视频输出对象AVCaptureMovieFileOutput及连接管理对象AVCaptureConnection,还有视频稳定设置preferredVideoStabilizationMode,视频旋转方向setVideoOrientation等

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- (void)addMovieOutput
{
    _movieOutput = [[AVCaptureMovieFileOutput alloc] init];
    if ([_captureSession canAddOutput:_movieOutput]) {
        [_captureSession addOutput:_movieOutput];
        AVCaptureConnection *captureConnection = [_movieOutput connectionWithMediaType:AVMediaTypeVideo];
        if ([captureConnection isVideoStabilizationSupported]) {
            captureConnection.preferredVideoStabilizationMode = AVCaptureVideoStabilizationModeAuto;
        }
        captureConnection.videoScaleAndCropFactor = captureConnection.videoMaxScaleAndCropFactor;
    }
}

相关枚举

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//设置视频旋转方向
/*
 typedef NS_ENUM(NSInteger, AVCaptureVideoOrientation) {
 AVCaptureVideoOrientationPortrait           = 1,
 AVCaptureVideoOrientationPortraitUpsideDown = 2,
 AVCaptureVideoOrientationLandscapeRight     = 3,
 AVCaptureVideoOrientationLandscapeLeft      = 4,
 } NS_AVAILABLE(10_7, 4_0) __TVOS_PROHIBITED;
 */

audio 相关

咱们再接着添加音频相关的,包括音频输入设备AVCaptureDevice,音频输入对象AVCaptureDeviceInput,并且将音频输入对象添加到会话

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- (void)addAudio
{
    NSError *audioError;
    _audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
    _audioInput = [[AVCaptureDeviceInput alloc] initWithDevice:_audioDevice error:&audioError];
    if (audioError) {
        NSLog(@"取得录音设备时出错 ------ %@",audioError);
        return;
    }
    if ([_captureSession canAddInput:_audioInput]) {
        [_captureSession addInput:_audioInput];
    }
}
AVCaptureVideoPreviewLayer

通过会话AVCaptureSession创建预览层AVCaptureVideoPreviewLayer,设置填充模式videoGravity,预览图层方向videoOrientation,并且设置 layer 想要显示的位置

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- (void)addPreviewLayer
{
    _captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
    _captureVideoPreviewLayer.frame = self.view.layer.bounds;
//    _captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    
    _captureVideoPreviewLayer.connection.videoOrientation = [_movieOutput connectionWithMediaType:AVMediaTypeVideo].videoOrientation;
    _captureVideoPreviewLayer.position = CGPointMake(self.view.width*0.5,self.videoView.height*0.5);
    
    CALayer *layer = self.videoView.layer;
    layer.masksToBounds = true;
    [self.view layoutIfNeeded];
    [layer addSublayer:_captureVideoPreviewLayer];
    
}

相关枚举

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/* 填充模式
     Options are AVLayerVideoGravityResize, AVLayerVideoGravityResizeAspect and AVLayerVideoGravityResizeAspectFill. AVLayerVideoGravityResizeAspect is default.
     */

最后,开始录制视频,结束录制视频,重新录制

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- (void)startRecord
{
    [_movieOutput startRecordingToOutputFileURL:[self outPutFileURL] recordingDelegate:self];
}
- (NSURL *)outPutFileURL
{
    return [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@%@", NSTemporaryDirectory(), @"outPut.mov"]];
}
- (void)stopRecord
{
    [_movieOutput stopRecording];
}
录制相关delegate

包括开始录制,录制结束等

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- (void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections
{
    NSLog(@"---- 开始录制 ----");
}
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error
{
    NSLog(@"---- 录制结束 ----%@ ",captureOutput.outputFileURL);
    
    if (self.canSave) {
        [self pushToPlay:captureOutput.outputFileURL];
        self.canSave = NO;
    }
}
压缩/保存视频

咱们需要把录制完毕的视频保存下来.而通常录制完毕的视频是很大的,咱们需要压缩一下再保存.

可以通过AVAssetExportSession来进行压缩,并且可以优化网络shouldOptimizeForNetworkUse,设置转后的格式outputFileType,并且开启异步压缩exportAsynchronouslyWithCompletionHandler

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#pragma mark 保存压缩
- (NSURL *)compressedURL
{
    return [NSURL fileURLWithPath:[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, true) lastObject] stringByAppendingPathComponent:[NSString stringWithFormat:@"compressed.mp4"]]];
}
- (CGFloat)fileSize:(NSURL *)path
{
    return [[NSData dataWithContentsOfURL:path] length]/1024.00 /1024.00;
}
// 压缩视频
- (IBAction)compressVideo:(id)sender
{
    NSLog(@"开始压缩,压缩前大小 %f MB",[self fileSize:self.videoUrl]);
    
    AVURLAsset *avAsset = [[AVURLAsset alloc] initWithURL:self.videoUrl options:nil];
    NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];
    if ([compatiblePresets containsObject:AVAssetExportPresetLowQuality]) {
        
        AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:avAsset presetName:AVAssetExportPreset640x480];
        exportSession.outputURL = [self compressedURL];
        exportSession.shouldOptimizeForNetworkUse = true;
        exportSession.outputFileType = AVFileTypeMPEG4;
        [exportSession exportAsynchronouslyWithCompletionHandler:^{
            if ([exportSession status] == AVAssetExportSessionStatusCompleted) {
                NSLog(@"压缩完毕,压缩后大小 %f MB",[self fileSize:[self compressedURL]]);
                [self saveVideo:[self compressedURL]];
            }else{
                NSLog(@"当前压缩进度:%f",exportSession.progress);
            }
        }];
    }
}
- (void)saveVideo:(NSURL *)outputFileURL
{
    ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
    [library writeVideoAtPathToSavedPhotosAlbum:outputFileURL
                                completionBlock:^(NSURL *assetURL, NSError *error) {
                                    if (error) {
                                        NSLog(@"保存视频失败:%@",error);
                                    } else {
                                        NSLog(@"保存视频到相册成功");
                                    }
                                }];
}
播放录制完的视频以及重复播放

播放录制的视频,以及重复播放

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- (void)create
{
    _playItem = [AVPlayerItem playerItemWithURL:self.videoUrl];
    _player = [AVPlayer playerWithPlayerItem:_playItem];
    _playerLayer =[AVPlayerLayer playerLayerWithPlayer:_player];
    _playerLayer.frame = CGRectMake(200, 200, 100, 100);
    _playerLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//视频填充模式
    [self.view.layer addSublayer:_playerLayer];
    [_player play];
}
-(void)playbackFinished:(NSNotification *)notification
{
    [_player seekToTime:CMTimeMake(0, 1)];
    [_player play];
}

交互相关

接下来,是一些和交互相关的,比如切换摄像头,开关闪光灯,还有白平衡啥的.

注意,改变设备属性前一定要首先调用lockForConfiguration方法加锁,调用完之后使用unlockForConfiguration方法解锁.

意义是—进行设备属性修改期间,先锁定设备,防止多处同时修改设备.因为可能有多处不同的修改,咱们将其封装起来最好

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-(void)changeDevicePropertySafety:(void (^)(AVCaptureDevice *captureDevice))propertyChange{
    
    //也可以直接用_videoDevice,但是下面这种更好
    AVCaptureDevice *captureDevice= [_videoInput device];
    NSError *error;
    
    BOOL lockAcquired = [captureDevice lockForConfiguration:&error];
    if (!lockAcquired) {
        NSLog(@"锁定设备过程error，错误信息：%@",error.localizedDescription);
    }else{
        [_captureSession beginConfiguration];
        propertyChange(captureDevice);
        [captureDevice unlockForConfiguration];
        [_captureSession commitConfiguration];
    }
}
开/关闪光灯

闪光模式开启后,并无明显感觉,所以还需要开启手电筒,并且开启前先判断是否自持,否则崩溃

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- (IBAction)changeFlashlight:(UIButton *)sender {
    
    BOOL con1 = [_videoDevice hasTorch];    //支持手电筒模式
    BOOL con2 = [_videoDevice hasFlash];    //支持闪光模式
    
    if (con1 && con2)
    {
        [self changeDevicePropertySafety:^(AVCaptureDevice *captureDevice) {
            if (_videoDevice.flashMode == AVCaptureFlashModeOn)         //闪光灯开
            {
                [_videoDevice setFlashMode:AVCaptureFlashModeOff];
                [_videoDevice setTorchMode:AVCaptureTorchModeOff];
            }else if (_videoDevice.flashMode == AVCaptureFlashModeOff)  //闪光灯关
            {
                [_videoDevice setFlashMode:AVCaptureFlashModeOn];
                [_videoDevice setTorchMode:AVCaptureTorchModeOn];
            }
        }];
        sender.selected=!sender.isSelected;
    }else{
        NSLog(@"不能切换闪光模式");
    }
}
切换摄像头

根据现在正在使用的摄像头来判断需要切换的摄像头

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- (IBAction)changeCamera{
    
    switch (_videoDevice.position) {
        case AVCaptureDevicePositionBack:
            _videoDevice = [self deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionFront];
            break;
        case AVCaptureDevicePositionFront:
            _videoDevice = [self deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack];
            break;
        default:
            return;
            break;
    }
    
    [self changeDevicePropertySafety:^(AVCaptureDevice *captureDevice) {
        NSError *error;
        AVCaptureDeviceInput *newVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:_videoDevice error:&error];
        
        if (newVideoInput != nil) {
            //必选先 remove 才能询问 canAdd
            [_captureSession removeInput:_videoInput];
            if ([_captureSession canAddInput:newVideoInput]) {
                [_captureSession addInput:newVideoInput];
                _videoInput = newVideoInput;
            }else{
                [_captureSession addInput:_videoInput];
            }
            
        } else if (error) {
            NSLog(@"切换前/后摄像头失败, error = %@", error);
        }
    }];
}
聚焦模式,曝光模式,拉近/远镜头(焦距)

同时存在单击和双击的手势,咱们如下设置,requireGestureRecognizerToFail的作用就是每次只生效一个手势

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-(void)addGenstureRecognizer{
    
    UITapGestureRecognizer *singleTapGesture=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(singleTap:)];
    singleTapGesture.numberOfTapsRequired = 1;
    singleTapGesture.delaysTouchesBegan = YES;
    UITapGestureRecognizer *doubleTapGesture=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(doubleTap:)];
    doubleTapGesture.numberOfTapsRequired = 2;
    doubleTapGesture.delaysTouchesBegan = YES;
    
    [singleTapGesture requireGestureRecognizerToFail:doubleTapGesture];
    [self.videoView addGestureRecognizer:singleTapGesture];
    [self.videoView addGestureRecognizer:doubleTapGesture];
}

单击修改聚焦模式setFocusMode及聚焦点setFocusPointOfInterest,还有曝光模式setExposureMode及曝光点setExposurePointOfInterest

注意,摄像头的点范围是0~1,咱们需要把点转化一下,使用captureDevicePointOfInterestForPoint

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-(void)singleTap:(UITapGestureRecognizer *)tapGesture{
    
    CGPoint point= [tapGesture locationInView:self.videoView];
    
    CGPoint cameraPoint= [_captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];
    [self setFocusCursorAnimationWithPoint:point];
    
    [self changeDevicePropertySafety:^(AVCaptureDevice *captureDevice) {
        
        //聚焦
        if ([captureDevice isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]) {
            [captureDevice setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
        }else{
            NSLog(@"聚焦模式修改失败");
        }
        
        //聚焦点的位置
        if ([captureDevice isFocusPointOfInterestSupported]) {
            [captureDevice setFocusPointOfInterest:cameraPoint];
        }
        
        //曝光模式
        if ([captureDevice isExposureModeSupported:AVCaptureExposureModeAutoExpose]) {
            [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];
        }else{
            NSLog(@"曝光模式修改失败");
        }
        
        //曝光点的位置
        if ([captureDevice isExposurePointOfInterestSupported]) {
            [captureDevice setExposurePointOfInterest:cameraPoint];
        }
        
    }];
}

下面是双击设置焦距videoZoomFactor

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-(void)doubleTap:(UITapGestureRecognizer *)tapGesture{
    
    NSLog(@"双击");
    
    [self changeDevicePropertySafety:^(AVCaptureDevice *captureDevice) {
        if (captureDevice.videoZoomFactor == 1.0) {
            CGFloat current = 1.5;
            if (current < captureDevice.activeFormat.videoMaxZoomFactor) {
                [captureDevice rampToVideoZoomFactor:current withRate:10];
            }
        }else{
            [captureDevice rampToVideoZoomFactor:1.0 withRate:10];
        }
    }];
}

相关枚举

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/*
         @constant AVCaptureFocusModeLocked 锁定在当前焦距
         Indicates that the focus should be locked at the lens' current position.
         
         @constant AVCaptureFocusModeAutoFocus 自动对焦一次,然后切换到焦距锁定
         Indicates that the device should autofocus once and then change the focus mode to AVCaptureFocusModeLocked.
         
         @constant AVCaptureFocusModeContinuousAutoFocus 当需要时.自动调整焦距
         Indicates that the device should automatically focus when needed.
         */
/*
         @constant AVCaptureExposureModeLocked  曝光锁定在当前值
         Indicates that the exposure should be locked at its current value.
         
         @constant AVCaptureExposureModeAutoExpose 曝光自动调整一次然后锁定
         Indicates that the device should automatically adjust exposure once and then change the exposure mode to AVCaptureExposureModeLocked.
         
         @constant AVCaptureExposureModeContinuousAutoExposure 曝光自动调整
         Indicates that the device should automatically adjust exposure when needed.
         
         @constant AVCaptureExposureModeCustom 曝光只根据设定的值来
         Indicates that the device should only adjust exposure according to user provided ISO, exposureDuration values.
         
         */

Demo

终于说完了,感觉越到后面越无力,还是放上一个 demo 吧,里面包含了上面介绍的两种方式.

Demo 下载地址


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