【移动应用开发技术】怎么在iOS中使用AVCaptureSession实现视频录制功能

【移动应用开发技术】怎么在iOS中使用AVCaptureSession实现视频录制功能

本篇文章给大家分享的是有关怎么在iOS中使用AVCaptureSession实现视频录制功能，在下觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着在下一起来看看吧。具体内容如下#import

"RecordingVideoViewController.h"

#import

<AVFoundation/AVFoundation.h>

#import

<AssetsLibrary/AssetsLibrary.h>

@interface

RecordingVideoViewController

()<AVCaptureFileOutputRecordingDelegate>

//会话

负责输入和输出设备之间的数据传递

@property

(strong,nonatomic)

AVCaptureSession

*captureSession;

//设备输入

负责从AVCaptureDevice获得输入数据

@property

(strong,nonatomic)

AVCaptureDeviceInput

*videoCaptureDeviceInput;

@property

(strong,nonatomic)

AVCaptureDeviceInput

*audioCaptureDeviceInput;

//视频输出流

@property

(strong,nonatomic)

AVCaptureMovieFileOutput

*captureMovieFileOutput;

//相机拍摄预览图层

@property

(strong,nonatomic)

AVCaptureVideoPreviewLayer

*captureVideoPreviewLayer;

//自定义UI控件容器

@property

(strong,nonatomic)

UIView

*viewContainer;

//聚焦图标

@property

(strong,nonatomic)

UIImageView

*focusCursor;

//录制时长

@property

(strong,nonatomic)

UILabel

*timeLabel;

//切换前后摄像头

@property

(strong,nonatomic)

UIButton

*switchCameraBtn;

//改变焦距

@property

(strong,nonatomic)

UIButton

*scaleBtn;

//计时器

@property

(strong,nonatomic)

NSTimer

*timer;

@end

@implementation

RecordingVideoViewController

{

@private

NSInteger

_num;

CGFloat

_kCameraScale;

}

-

(UIView

*)viewContainer

{

if

(!_viewContainer)

{

_viewContainer

=

[[UIView

alloc]

initWithFrame:[UIScreen

mainScreen].bounds];

UIButton

*takeButton

=

[UIButton

buttonWithType:UIButtonTypeCustom];

takeButton.backgroundColor

=

[UIColor

redColor];

[takeButton

setTitle:@"start"

forState:UIControlStateNormal];

[takeButton

addTarget:self

action:@selector(takeButtonClick:)

forControlEvents:UIControlEventTouchUpInside];

_timeLabel

=

[[UILabel

alloc]

init];

_timeLabel.textColor

=

[UIColor

redColor];

_timeLabel.textAlignment

=

NSTextAlignmentCenter;

_timeLabel.font

=

[UIFont

boldSystemFontOfSize:20];

_timeLabel.text

=

@"00:00";

_switchCameraBtn

=

[UIButton

buttonWithType:UIButtonTypeCustom];

[_switchCameraBtn

setTitle:@"switch"

forState:UIControlStateNormal];

_switchCameraBtn.backgroundColor

=

[UIColor

redColor];

[_switchCameraBtn

addTarget:self

action:@selector(switchCameraBtnClick)

forControlEvents:UIControlEventTouchUpInside];

_scaleBtn

=

[UIButton

buttonWithType:UIButtonTypeCustom];

[_scaleBtn

setTitle:@"1X"

forState:UIControlStateNormal];

_scaleBtn.backgroundColor

=

[UIColor

redColor];

[_scaleBtn

addTarget:self

action:@selector(scaleBtnClick:)

forControlEvents:UIControlEventTouchUpInside];

[_viewContainer

addSubview:takeButton];

[_viewContainer

addSubview:_timeLabel];

[_viewContainer

addSubview:_scaleBtn];

[_viewContainer

addSubview:_switchCameraBtn];

[takeButton

mas_makeConstraints:^(MASConstraintMaker

*make)

{

make.size.mas_equalTo(CGSizeMake(60,

40));

make.centerX.mas_equalTo(_viewContainer);

make.bottom.mas_equalTo(_viewContainer).offset(-64);

}];

[_timeLabel

mas_makeConstraints:^(MASConstraintMaker

*make)

{

make.centerX.mas_equalTo(_viewContainer);

make.height.mas_equalTo(@30);

make.top.mas_equalTo(_viewContainer);

}];

[_scaleBtn

mas_makeConstraints:^(MASConstraintMaker

*make)

{

make.size.mas_equalTo(CGSizeMake(60,

40));

make.left.mas_equalTo(_viewContainer).offset(10);

make.top.mas_equalTo(_viewContainer);

}];

[_switchCameraBtn

mas_makeConstraints:^(MASConstraintMaker

*make)

{

make.size.mas_equalTo(CGSizeMake(60,

40));

make.top.mas_equalTo(_viewContainer);

make.right.mas_equalTo(_viewContainer).offset(-10);

}];

_focusCursor

=

[[UIImageView

alloc]

init];

kBorder(_focusCursor,

1,

[UIColor

yellowColor]);

_focusCursor.alpha

=

0;

[_viewContainer

addSubview:self.focusCursor];

[_focusCursor

mas_makeConstraints:^(MASConstraintMaker

*make)

{

make.size.mas_equalTo(CGSizeMake(40,

40));

make.center.mas_equalTo(_viewContainer);

}];

}

return

_viewContainer;

}

-

(void)viewDidLoad

{

[super

viewDidLoad];

self.title

=

@"视频录制";

_kCameraScale

=

1.0f;

//初始化会话对象

_captureSession

=

[[AVCaptureSession

alloc]

init];

if

([_captureSession

canSetSessionPreset:AVCaptureSessionPreset1280x720])

{

_captureSession.sessionPreset

=

AVCaptureSessionPreset1280x720;

}

NSError

*error

=

nil;

//获取视频输入对象

AVCaptureDevice

*videoCaptureDevice

=

[self

cameraDeviceWithPosition:(AVCaptureDevicePositionBack)];

if

(!videoCaptureDevice)

{

NSLog(@"获取后置摄像头失败！");

return;

}

_videoCaptureDeviceInput

=

[[AVCaptureDeviceInput

alloc]

initWithDevice:videoCaptureDevice

error:&error];

if

(error)

{

NSLog(@"取得视频设备输入对象时出错");

return;

}

//获取音频输入对象

AVCaptureDevice

*audioCatureDevice

=

[[AVCaptureDevice

devicesWithMediaType:AVMediaTypeAudio]

firstObject];

_audioCaptureDeviceInput

=

[[AVCaptureDeviceInput

alloc]

initWithDevice:audioCatureDevice

error:&error];

if

(error)

{

NSLog(@"取得音频设备输入对象时出错");

return;

}

//初始化设备输出对象

_captureMovieFileOutput

=

[[AVCaptureMovieFileOutput

alloc]

init];

//将设备输入添加到会话中

if

([_captureSession

canAddInput:_videoCaptureDeviceInput])

{

[_captureSession

addInput:_videoCaptureDeviceInput];

[_captureSession

addInput:_audioCaptureDeviceInput];

//防抖功能

AVCaptureConnection

*captureConnection

=

[_captureMovieFileOutput

connectionWithMediaType:AVMediaTypeAudio];

if

([captureConnection

isVideoStabilizationSupported])

{

captureConnection.preferredVideoStabilizationMode

=

AVCaptureVideoStabilizationModeAuto;

}

}

//将设备输出添加到会话中

if

([_captureSession

canAddOutput:_captureMovieFileOutput])

{

[_captureSession

addOutput:_captureMovieFileOutput];

}

//创建视频预览图层

_captureVideoPreviewLayer

=

[[AVCaptureVideoPreviewLayer

alloc]

initWithSession:_captureSession];

self.viewContainer.layer.masksToBounds

=

YES;

_captureVideoPreviewLayer.frame

=

self.viewContainer.bounds;

_captureVideoPreviewLayer.videoGravity

=

AVLayerVideoGravityResizeAspectFill;

[self.view.layer

addSublayer:_captureVideoPreviewLayer];

//显示自定义控件

[self.view

addSubview:self.viewContainer];

//添加点按聚焦手势

UITapGestureRecognizer

*tapGesture

=

[[UITapGestureRecognizer

alloc]initWithTarget:self

action:@selector(tapScreen:)];

[self.viewContainer

addGestureRecognizer:tapGesture];

}

-(void)viewDidAppear:(BOOL)animated{

[super

viewDidAppear:animated];

[self.captureSession

startRunning];

}

-(void)viewDidDisappear:(BOOL)animated{

[super

viewDidDisappear:animated];

[self.captureSession

stopRunning];

[self.timer

invalidate];

self.timer

=

nil;

}

-

(void)viewWillDisappear:(BOOL)animated

{

[super

viewWillDisappear:animated];

[self.captureVideoPreviewLayer

setAffineTransform:CGAffineTransformMakeScale(1,

1)];

}

-

(void)didReceiveMemoryWarning

{

[super

didReceiveMemoryWarning];

}

//开始

+

暂停录制

-

(void)takeButtonClick:(UIButton

*)sender

{

if

([self.captureMovieFileOutput

isRecording])

{

[self.captureMovieFileOutput

stopRecording];

[self.navigationController

popViewControllerAnimated:YES];

}

else

{

AVCaptureConnection

*captureConnection

=

[self.captureMovieFileOutput

connectionWithMediaType:AVMediaTypeVideo];

captureConnection.videoOrientation

=

[self.captureVideoPreviewLayer

connection].videoOrientation;

NSString

*filePath

=

[NSTemporaryDirectory()

stringByAppendingPathComponent:@"Movie.mov"];

NSLog(@"%@",filePath);

[self.captureMovieFileOutput

startRecordingToOutputFileURL:[NSURL

fileURLWithPath:filePath]

recordingDelegate:self];

self.switchCameraBtn.hidden

=

YES;

sender.backgroundColor

=

[UIColor

greenColor];

[sender

setTitle:@"stop"

forState:UIControlStateNormal];

self.timer

=

[NSTimer

scheduledTimerWithTimeInterval:1

target:self

selector:@selector(timeAction)

userInfo:nil

repeats:YES];

[self.timer

setFireDate:[NSDate

distantPast]];

}

}

//切换摄像头

-

(void)switchCameraBtnClick

{

AVCaptureDevicePosition

currentPosition

=

self.videoCaptureDeviceInput.device.position;

AVCaptureDevicePosition

toPosition;

if

(currentPosition

==

AVCaptureDevicePositionUnspecified

||

currentPosition

==

AVCaptureDevicePositionFront)

{

toPosition

=

AVCaptureDevicePositionBack;

}

else

{

toPosition

=

AVCaptureDevicePositionFront;

}

AVCaptureDevice

*toCapturDevice

=

[self

cameraDeviceWithPosition:toPosition];

if

(!toCapturDevice)

{

NSLog(@"获取要切换的设备失败");

return;

}

NSError

*error

=

nil;

AVCaptureDeviceInput

*toVideoDeviceInput

=

[[AVCaptureDeviceInput

alloc]

initWithDevice:toCapturDevice

error:&error];

if

(error)

{

NSLog(@"获取要切换的设备输入失败");

return;

}

//改变会话配置

[self.captureSession

beginConfiguration];

[self.captureSession

removeInput:self.videoCaptureDeviceInput];

if

([self.captureSession

canAddInput:toVideoDeviceInput])

{

[self.captureSession

addInput:toVideoDeviceInput];

self.videoCaptureDeviceInput

=

toVideoDeviceInput;

}

//提交会话配置

[self.captureSession

commitConfiguration];

}

//点按手势

-

(void)tapScreen:(UITapGestureRecognizer

*)tap

{

CGPoint

point

=

[tap

locationInView:self.viewContainer];

//将界面point对应到摄像头point

CGPoint

cameraPoint

=

[self.captureVideoPreviewLayer

captureDevicePointOfInterestForPoint:point];

//设置聚光动画

self.focusCursor.center

=

point;

self.focusCursor.transform

=

CGAffineTransformMakeScale(1.5,

1.5);

self.focusCursor.alpha

=

1.0f;

[UIView

animateWithDuration:1

animations:^{

self.focusCursor.transform

=

CGAffineTransformIdentity;

}

completion:^(BOOL

finished)

{

self.focusCursor.alpha

=

0.0f;

}];

//设置聚光点坐标

[self

focusWithMode:AVCaptureFocusModeAutoFocus

exposureMode:AVCaptureExposureModeAutoExpose

atPoint:cameraPoint];

}

/**设置聚焦点*/

-(void)focusWithMode:(AVCaptureFocusMode)focusMode

exposureMode:(AVCaptureExposureMode)exposureMode

atPoint:(CGPoint)point{

AVCaptureDevice

*captureDevice=

[self.videoCaptureDeviceInput

device];

NSError

*error

=

nil;

//设置设备属性必须先解锁

然后加锁

if

([captureDevice

lockForConfiguration:&error])

{

if

([captureDevice

isFocusModeSupported:focusMode])

{

[captureDevice

setFocusMode:focusMode];

}

if

([captureDevice

isFocusPointOfInterestSupported])

{

[captureDevice

setFocusPointOfInterest:point];

}

//

//曝光

//

if

([captureDevice

isExposureModeSupported:exposureMode])

{

//

[captureDevice

setExposureMode:exposureMode];

//

}

//

if

([captureDevice

isExposurePointOfInterestSupported])

{

//

[captureDevice

setExposurePointOfInterest:point];

//

}

//

//闪光灯模式

//

if

([captureDevice

isFlashModeSupported:AVCaptureFlashModeAuto])

{

//

[captureDevice

setFlashMode:AVCaptureFlashModeAuto];

//

}

//加锁

[captureDevice

unlockForConfiguration];

}else{

NSLog(@"设置设备属性过程发生错误，错误信息：%@",error.localizedDescription);

}

}

//调整焦距

-(void)scaleBtnClick:(UIButton

*)sender

{

_kCameraScale

+=

0.5;

if(_kCameraScale

>

3.0)

{

_kCameraScale

=

1.0;

}

//改变焦距

AVCaptureDevice

*videoDevice

=

self.videoCaptureDeviceInput.device;

NSError

*error

=

nil;

if

([videoDevice

lockForConfiguration:&error])

{

[videoDevice

setVideoZoomFactor:_kCameraScale];

[videoDevice

unlockForConfiguration];

[sender

setTitle:[NSString

stringWithFormat:@"%lgX",_kCameraScale]

forState:UIControlStateNormal];

[CATransaction

begin];

[CATransaction

setAnimationDuration:0.25];

[self.captureVideoPreviewLayer

setAffineTransform:CGAffineTransformMakeScale(_kCameraScale,

_kCameraScale)];

[CATransaction

commit];

}

else

{

NSLog(@"修改设备属性失败!")

}

}

#pragma

mark

AVCaptureFileOutputRecordingDelegate

-

(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");

ALAssetsLibrary

*assetsLibrary

=

[[ALAssetsLibrary

alloc]

init];

[assetsLibrary

writeVideoAtPathToSavedPhotosAlbum:outputFileURL

completionBlock:^(NSURL

*assetURL,

NSError

*error)

{

if

(error)

{

NSLog(@"保存视频到相簿过程中发生错误，错误信息：%@",error.localizedDescription);

}

}];

}

//录制计时

-

(void)timeAction

{

self.timeLabel.text

=

[NSString

stringWithFormat:@"%.2ld:%.2ld",_num/60,_num%60];

_num

++;

}

/**取得指定位置的摄像头*/

-

(AVCaptureDevice

*)cameraDeviceWithPosition:(AVCaptureDevicePosition

)position{

NSArray

*cameras

=

[AVCaptureDevice

devicesWithMediaType:AVMediaTypeVideo];

for

(AVCaptureDevice

*camera

in

cameras)

{

if

([camera

position]

==

position)

{

return

camera;

}

}

return

nil;

}

@end参考代码：#import

"VideoTestViewController.h"

#import

<AVFoundation/AVFoundation.h>

#import

<AssetsLibrary/AssetsLibrary.h>

typedef

void(^PropertyChangeBlock)(AVCaptureDevice

*captureDevice);

@interface

VideoTestViewController

()<AVCaptureFileOutputRecordingDelegate>//视频文件输出代理

@property

(strong,nonatomic)

AVCaptureSession

*captureSession;//负责输入和输出设备之间的数据传递

@property

(strong,nonatomic)

AVCaptureDeviceInput

*captureDeviceInput;//负责从AVCaptureDevice获得输入数据

@property

(strong,nonatomic)

AVCaptureMovieFileOutput

*captureMovieFileOutput;//视频输出流

@property

(strong,nonatomic)

AVCaptureVideoPreviewLayer

*captureVideoPreviewLayer;//相机拍摄预览图层

@property

(assign,nonatomic)

BOOL

enableRotation;//是否允许旋转（注意在视频录制过程中禁止屏幕旋转）

@property

(assign,nonatomic)

CGRect

*lastBounds;//旋转的前大小

@property

(assign,nonatomic)

UIBackgroundTaskIdentifier

backgroundTaskIdentifier;//后台任务标识

@property

(strong,nonatomic)

UIView

*viewContainer;

@property

(strong,nonatomic)

UIButton

*takeButton;//拍照按钮

@property

(strong,nonatomic)

UIImageView

*focusCursor;

//聚焦光标

@end

@implementation

VideoTestViewController

#pragma

mark

-

控制器视图方法

-

(void)viewDidLoad

{

[super

viewDidLoad];

}

-(void)viewWillAppear:(BOOL)animated{

[super

viewWillAppear:animated];

//初始化会话

_captureSession=[[AVCaptureSession

alloc]init];

if

([_captureSession

canSetSessionPreset:AVCaptureSessionPreset1280x720])

{//设置分辨率

_captureSession.sessionPreset=AVCaptureSessionPreset1280x720;

}

//获得输入设备

AVCaptureDevice

*captureDevice=[self

getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置摄像头

if

(!captureDevice)

{

NSLog(@"取得后置摄像头时出现问题.");

return;

}

//添加一个音频输入设备

AVCaptureDevice

*audioCaptureDevice=[[AVCaptureDevice

devicesWithMediaType:AVMediaTypeAudio]

firstObject];

NSError

*error=nil;

//根据输入设备初始化设备输入对象，用于获得输入数据

_captureDeviceInput=[[AVCaptureDeviceInput

alloc]initWithDevice:captureDevice

error:&error];

if

(error)

{

NSLog(@"取得设备输入对象时出错，错误原因：%@",error.localizedDescription);

return;

}

AVCaptureDeviceInput

*audioCaptureDeviceInput=[[AVCaptureDeviceInput

alloc]initWithDevice:audioCaptureDevice

error:&error];

if

(error)

{

NSLog(@"取得设备输入对象时出错，错误原因：%@",error.localizedDescription);

return;

}

//初始化设备输出对象，用于获得输出数据

_captureMovieFileOutput=[[AVCaptureMovieFileOutput

alloc]init];

//将设备输入添加到会话中

if

([_captureSession

canAddInput:_captureDeviceInput])

{

[_captureSession

addInput:_captureDeviceInput];

[_captureSession

addInput:audioCaptureDeviceInput];

AVCaptureConnection

*captureConnection=[_captureMovieFileOutput

connectionWithMediaType:AVMediaTypeVideo];

if

([captureConnection

isVideoStabilizationSupported

])

{

captureConnection.preferredVideoStabilizationMode=AVCaptureVideoStabilizationModeAuto;

}

}

//将设备输出添加到会话中

if

([_captureSession

canAddOutput:_captureMovieFileOutput])

{

[_captureSession

addOutput:_captureMovieFileOutput];

}

//创建视频预览层，用于实时展示摄像头状态

_captureVideoPreviewLayer=[[AVCaptureVideoPreviewLayer

alloc]initWithSession:self.captureSession];

CALayer

*layer=self.viewContainer.layer;

layer.masksToBounds=YES;

_captureVideoPreviewLayer.frame=layer.bounds;

_captureVideoPreviewLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//填充模式

//将视频预览层添加到界面中

//[layer

addSublayer:_captureVideoPreviewLayer];

[layer

insertSublayer:_captureVideoPreviewLayer

below:self.focusCursor.layer];

_enableRotation=YES;

[self

addNotificationToCaptureDevice:captureDevice];

[self

addGenstureRecognizer];

}

-(void)viewDidAppear:(BOOL)animated{

[super

viewDidAppear:animated];

[self.captureSession

startRunning];

}

-(void)viewDidDisappear:(BOOL)animated{

[super

viewDidDisappear:animated];

[self.captureSession

stopRunning];

}

-

(void)didReceiveMemoryWarning

{

[super

didReceiveMemoryWarning];

}

-(BOOL)shouldAutorotate{

return

self.enableRotation;

}

////屏幕旋转时调整视频预览图层的方向

//-(void)willTransitionToTraitCollection:(UITraitCollection

*)newCollection

withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator{

//

[super

willTransitionToTraitCollection:newCollection

withTransitionCoordinator:coordinator];

////

NSLog(@"%i,%i",newCollection.verticalSizeClass,newCollection.horizontalSizeClass);

//

UIInterfaceOrientation

orientation

=

[[UIApplication

sharedApplication]

statusBarOrientation];

//

NSLog(@"%i",orientation);

//

AVCaptureConnection

*captureConnection=[self.captureVideoPreviewLayer

connection];

//

captureConnection.videoOrientation=orientation;

//

//}

//屏幕旋转时调整视频预览图层的方向

-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation

duration:(NSTimeInterval)duration{

AVCaptureConnection

*captureConnection=[self.captureVideoPreviewLayer

connection];

captureConnection.videoOrientation=(AVCaptureVideoOrientation)toInterfaceOrientation;

}

//旋转后重新设置大小

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{

_captureVideoPreviewLayer.frame=self.viewContainer.bounds;

}

-(void)dealloc{

[self

removeNotification];

}

#pragma

mark

-

UI方法

#pragma

mark

视频录制

-

(void)takeButtonClick:(UIButton

*)sender

{

//根据设备输出获得连接

AVCaptureConnection

*captureConnection=[self.captureMovieFileOutput

connectionWithMediaType:AVMediaTypeVideo];

//根据连接取得设备输出的数据

if

(![self.captureMovieFileOutput

isRecording])

{

self.enableRotation=NO;

//如果支持多任务则则开始多任务

if

([[UIDevice

currentDevice]

isMultitaskingSupported])

{

self.backgroundTaskIdentifier=[[UIApplication

sharedApplication]

beginBackgroundTaskWithExpirationHandler:nil];

}

//预览图层和视频方向保持一致

captureConnection.videoOrientation=[self.captureVideoPreviewLayer

connection].videoOrientation;

NSString

*outputFielPath=[NSTemporaryDirectory()

stringByAppendingString:@"myMovie.mov"];

NSLog(@"save

path

is

:%@",outputFielPath);

NSURL

*fileUrl=[NSURL

fileURLWithPath:outputFielPath];

[self.captureMovieFileOutput

startRecordingToOutputFileURL:fileUrl

recordingDelegate:self];

}

else{

[self.captureMovieFileOutput

stopRecording];//停止录制

}

}

#pragma

mark

切换前后摄像头

-

(void)toggleButtonClick:(UIButton

*)sender

{

AVCaptureDevice

*currentDevice=[self.captureDeviceInput

device];

AVCaptureDevicePosition

currentPosition=[currentDevice

position];

[self

removeNotificationFromCaptureDevice:currentDevice];

AVCaptureDevice

*toChangeDevice;

AVCaptureDevicePosition

toChangePosition=AVCaptureDevicePositionFront;

if

(currentPosition==AVCaptureDevicePositionUnspecified||currentPosition==AVCaptureDevicePositionFront)

{

toChangePosition=AVCaptureDevicePositionBack;

}

toChangeDevice=[self

getCameraDeviceWithPosition:toChangePosition];

[self

addNotificationToCaptureDevice:toChangeDevice];

//获得要调整的设备输入对象

AVCaptureDeviceInput

*toChangeDeviceInput=[[AVCaptureDeviceInput

alloc]initWithDevice:toChangeDevice

error:nil];

//改变会话的配置前一定要先开启配置，配置完成后提交配置改变

[self.captureSession

beginConfiguration];

//移除原有输入对象

[self.captureSession

removeInput:self.captureDeviceInput];

//添加新的输入对象

if

([self.captureSession

canAddInput:toChangeDeviceInput])

{

[self.captureSession

addInput:toChangeDeviceInput];

self.captureDeviceInput=toChangeDeviceInput;

}

//提交会话配置

[self.captureSession

commitConfiguration];

}

#pragma

mark

-

视频输出代理

-(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(@"视频录制完成.");

//视频录入完成之后在后台将视频存储到相簿

self.enableRotation=YES;

UIBackgroundTaskIdentifier

lastBackgroundTaskIdentifier=self.backgroundTaskIdentifier;

self.backgroundTaskIdentifier=UIBackgroundTaskInvalid;

ALAssetsLibrary

*assetsLibrary=[[ALAssetsLibrary

alloc]init];

[assetsLibrary

writeVideoAtPathToSavedPhotosAlbum:outputFileURL

completionBlock:^(NSURL

*assetURL,

NSError

*error)

{

if

(error)

{

NSLog(@"保存视频到相簿过程中发生错误，错误信息：%@",error.localizedDescription);

}

if

(lastBackgroundTaskIdentifier!=UIBackgroundTaskInvalid)

{

[[UIApplication

sharedApplication]

endBackgroundTask:lastBackgroundTaskIdentifier];

}

NSLog(@"成功保存视频到相簿.");

}];

}

#pragma

mark

-

通知

/**

*

给输入设备添加通知

*/

-(void)addNotificationToCaptureDevice:(AVCaptureDevice

*)captureDevice{

//注意添加区域改变捕获通知必须首先设置设备允许捕获

[self

changeDeviceProperty:^(AVCaptureDevice

*captureDevice)

{

captureDevice.subjectAreaChangeMonitoringEnabled=YES;

}];

NSNotificationCenter

*notificationCenter=

[NSNotificationCenter

defaultCenter];

//捕获区域发生改变

[notificationCenter

addObserver:self

selector:@selector(areaChange:)

name:AVCaptureDeviceSubjectAreaDidChangeNotification

object:captureDevice];

}

-(void)removeNotificationFromCaptureDevice:(AVCaptureDevice

*)captureDevice{

NSNotificationCenter

*notificationCenter=

[NSNotificationCenter

defaultCenter];

[notificationCenter

removeObserver:self

name:AVCaptureDeviceSubjectAreaDidChangeNotification

object:captureDevice];

}

/**

*

移除所有通知

*/

-(void)removeNotification{

NSNotificationCenter

*notificationCenter=

[NSNotificationCenter

defaultCenter];

[notificationCenter

removeObserver:self];

}

-(void)addNotificationToCaptureSession:(AVCaptureSession

*)captureSession{

NSNotificationCenter

*notificationCenter=

[NSNotificationCenter

defaultCenter];

//会话出错

[notificationCenter

addObserver:self

selector:@selector(sessionRuntimeError:)

name:AVCaptureSessionRuntimeErrorNotification

object:captureSession];

}

/**

*

设备连接成功

*

*

@param

notification

通知对象

*/

-(void)deviceConnected:(NSNotification

*)notification{

NSLog(@"设备已连接...");

}

/**

*

设备连接断开

*

*

@param

notification

通知对象

*/

-(void)deviceDisconnected:(NSNotification

*)notification{

NSLog(@"设备已断开.");

}

/**

*

捕获区域改变

*

*

@param

notification

通知对象

*/

-(void)areaChange:(NSNotification

*)notification{

NSLog(@"捕获区域改变...");

}

/**

*

会话出错

*

*

@param

notification

通知对象

*/

-(void)sessionRuntimeError:(NSNotification

*)notification{

NSLog(@"会话发生错误.");

}

#pragma

mark

-

私有方法

/**

*

取得指定位置的摄像头

*

*

@param

position

摄像头位置

*

*

@return

摄像头设备

*/

-(AVCaptureDevice

*)getCameraDeviceWithPosition:(AVCaptureDevicePosition

)position{

NSArray

*cameras=

[AVCaptureDevice

devicesWithMediaType:AVMediaTypeVideo];

for

(AVCaptureDevice

*camera

in

cameras)

{

if

([camera

position]==position)

{

return

camera;

}

}

return

nil;

}

/**

*

改变设备属性的统一操作方法

*

*

@param

propertyChange

属性改变操作

*/

-(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{

AVCaptureDevice

*captureDevice=

[self.captureDeviceInput

device];

NSError

*error;

//注意改变设备属性前一定要首先调用lockForConfiguration:调用完之后使用unlockForConfiguration方法解锁

if

([captureDevice

lockForConfiguration:&error])

{

propertyChange(captureDevice);

[captureDevice

unlockForConfiguration];

}else{

NSLog(@"设置设备属性过程发生错误，错误信息：%@",error.localizedDescription);

}

}

/**

*