AVFoundation--视频录制

//
//  ViewController.m
//  AVFoundationCameraRecording
//
//  Created by ZhuYi on 16/5/3.
//  Copyright © 2016年 DDP. All rights reserved.
//

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <AssetsLibrary/AssetsLibrary.h>
typedef void(^PropertyChangeBlock)(AVCaptureDevice *captureDevice);

@interface ViewController ()<AVCaptureFileOutputRecordingDelegate>{
    UIButton *takephotoButton;
    UIView *viewContainer;
}

@property (strong,nonatomic) AVCaptureSession *captureSession;//负责输入和输出设置之间的数据传递
@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) UIBackgroundTaskIdentifier backgroundTaskIdentifier;//后台任务标识

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    viewContainer = [[UIView alloc] initWithFrame:CGRectMake(, , self.view.frame.size.width, self.view.frame.size.height - )];
    [self.view addSubview:viewContainer];
    takephotoButton = [UIButton buttonWithType:UIButtonTypeCustom];
    takephotoButton.backgroundColor = [UIColor orangeColor];
    [takephotoButton addTarget:self action:@selector(takePhoto) forControlEvents:UIControlEventTouchUpInside];
    takephotoButton.frame = CGRectMake(, self.view.frame.size.height - , self.view.frame.size.width, );
    [self.view addSubview:takephotoButton];

    //初始化会话
    _captureSession=[[AVCaptureSession alloc]init];
    _captureSession.sessionPreset=AVCaptureSessionPreset1920x1080;

    //获得输入设备
    AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置摄像头

    //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];
    AVCaptureDeviceInput *audioCaptureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:audioCaptureDevice error:&error];

    //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=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];
    [self.captureSession startRunning];
}

/**
 *  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;
}

- (void)takePhoto{
    //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]) {
        //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];
        NSLog(@"fileUrl:%@",fileUrl);
        [self.captureMovieFileOutput startRecordingToOutputFileURL:fileUrl recordingDelegate:self];
    }
    else{
        [self.captureMovieFileOutput stopRecording];//停止录制
    }
}
-(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
    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);
        }
        NSLog(@"outputUrl:%@",outputFileURL);
        [[NSFileManager defaultManager] removeItemAtURL:outputFileURL error:nil];
        if (lastBackgroundTaskIdentifier!=UIBackgroundTaskInvalid) {
            [[UIApplication sharedApplication] endBackgroundTask:lastBackgroundTaskIdentifier];
        }
        NSLog(@"成功保存视频到相簿.");
    }];
}
@end