iOS 视频的录制、合成以及播放

根据项目要求，视频可以暂停然后继续录制。选择了视频合成。后面有链接

导入AVFoundation库文件用于支持：

AVCaptureSession 链接输入输出设备

AVCaptureDeviceInput 从设备获取输入设备

AVCaptureMovieFileOutput 视频输出

AVCaptureVideoPreviewLayer 录制预览layer

AVMutableComposition 根据MediaType返回音视频轨道

AVMutableVideoComposition 设施输出内容属性，大小，帧数。。。

AVAssetTrack 素材通道

AVURLAsset 获取音视频信息

AVAssetExportSession 输出视频

导入MediaPlayer库用于支持：

MPMoviePlayerController 视频播放控件

info.plist文件需要添加下面内容获取相应权限

Privacy - Camera Usage Description （是否允许此App使用你的相机？）

Privacy - Microphone Usage Description （是否允许此App使用你的麦克风？）

视频合成过程需要时间，这里没做处理，可以根据自己需要添加一个UIActivityIndicatorView

//
//  ViewController.m
//  VideoRecordText
//
//

#import "ViewController.h"

#import <AVFoundation/AVFoundation.h>
#import <MediaPlayer/MediaPlayer.h>

#define WIDTH [UIScreen mainScreen].bounds.size.width
#define HEIGHT [UIScreen mainScreen].bounds.size.height

@interface ViewController ()<AVCaptureFileOutputRecordingDelegate>

@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 (nonatomic,strong)NSString * fileName;//文件夹名
@property (nonatomic,assign)int fileNum;//文件名
@property (nonatomic,strong)NSMutableArray * fileUrlArr;//文件路径数组

@property (nonatomic,strong)MPMoviePlayerController * mediaV;//播放器

@property (nonatomic,strong)UIView * playBcgV;//播放页面

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
_fileUrlArr = [[NSMutableArray alloc]init];
_fileName = [NSString stringWithFormat:@"%d",(int)[[NSDate dateWithTimeIntervalSinceNow:0] timeIntervalSince1970]];
_fileNum = 0;

[self createPlayBcgV];//播放视图

[self createUI];

// Do any additional setup after loading the view, typically from a nib.
}

-(void)createUI{

UIView * layerView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, WIDTH, HEIGHT-140)];

layerView.backgroundColor = [UIColor blackColor];

//初始化会话
_captureSession=[[AVCaptureSession alloc]init];
[AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
if (granted) {
}else{
NSLog(@"未获取摄像头权限");
}
}];
//获得输入设备（视频）
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;
}

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(@"取得视频设备输入对象时出错，错误原因：%@",error.localizedDescription);
return;
}
//添加一个输入设备（音频）
AVCaptureDevice *audioCaptureDevice=[[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];

AVCaptureDeviceInput *audioCaptureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:audioCaptureDevice error:&error];
if (error) {
NSLog(@"取得音频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];

_captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

CALayer *layer= layerView.layer;
layer.masksToBounds=YES;
_captureVideoPreviewLayer.frame = CGRectMake(0, 0, WIDTH, HEIGHT);

//将视频预览层添加到界面中
[layer addSublayer:_captureVideoPreviewLayer];

[self.captureSession startRunning];

[self.view addSubview:layerView];

[self createButton];
}

#pragma mark --------------------清空按钮-------------------
-(void)clearBtnClick:(UIButton *)btn{
NSLog(@"清空");

UIButton * button = (UIButton *)[self.view viewWithTag:100];

if (button.selected) {
return;
}

NSFileManager* fileManager=[NSFileManager defaultManager];

NSString *pathDocuments = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *createPath = [NSString stringWithFormat:@"%@/myVidio", pathDocuments];

// 判断文件夹是否存在，如果存在，清空
if ([[NSFileManager defaultManager] fileExistsAtPath:createPath]) {
[fileManager removeItemAtPath:createPath error:nil];
}

}

#pragma mark --------------------视频录制-------------------
-(void)recordStartOrPause:(UIButton *)btn{

btn.selected = !btn.selected;

if (btn.selected) {//点击开始方法
NSLog(@"录制");

NSString * pathDocument = [self checkPath];
[_fileUrlArr addObject:pathDocument];

[_captureMovieFileOutput startRecordingToOutputFileURL:[NSURL fileURLWithPath:pathDocument] recordingDelegate:self];

_fileNum ++;

}else{//停止方法
NSLog(@"停止");

[_captureMovieFileOutput stopRecording];
}

}

-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error{

NSLog(@"录制完成");

}

#pragma mark --------------------录制完成-------------------
-(void)finishBtnClick:(UIButton *)btn{//点击进行视频合成操作并跳转到PlayViewController
UIButton * button = (UIButton *)[self.view viewWithTag:100];

if (button.selected) {
return;

}
NSLog(@"完成");

if (_fileUrlArr.count < 1) {
return;
}
//合成后视频出处路径
NSString *pathDocuments = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *createPath = [NSString stringWithFormat:@"%@/myVidio/%@/%@.mp4", pathDocuments,_fileName,_fileName];

if (_fileUrlArr.count > 1) {

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];

AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];

AVMutableCompositionTrack *audioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio
preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];

CMTime totalDuration = kCMTimeZero;

for (int i = 0; i < _fileUrlArr.count; i++) {
AVURLAsset *asset = [AVURLAsset assetWithURL:[NSURL fileURLWithPath:_fileUrlArr[i]]];
NSError *erroraudio = nil;//获取AVAsset中的音频 或者视频
AVAssetTrack *assetAudioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] firstObject];//向通道内加入音频或者视频
//                BOOL ba =
[audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration)
ofTrack:assetAudioTrack
atTime:totalDuration
error:&erroraudio];

//        NSLog(@"erroraudio:%@%d",erroraudio,ba);
NSError *errorVideo = nil;
AVAssetTrack *assetVideoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo]firstObject];

//                BOOL bl =
[videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, asset.duration)
ofTrack:assetVideoTrack
atTime:totalDuration
error:&errorVideo];

//        NSLog(@"errorVideo:%@%d",errorVideo,bl);
totalDuration = CMTimeAdd(totalDuration, asset.duration);

videoComposition.frameDuration = CMTimeMake(1, 30);
//视频输出尺寸
videoComposition.renderSize = CGSizeMake(assetVideoTrack.naturalSize.height,assetVideoTrack.naturalSize.height*(HEIGHT/(HEIGHT-140)));

AVMutableVideoCompositionInstruction * avMutableVideoCompositionInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];

[avMutableVideoCompositionInstruction setTimeRange:CMTimeRangeMake(kCMTimeZero, [mixComposition duration])];

AVMutableVideoCompositionLayerInstruction * avMutableVideoCompositionLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:assetAudioTrack];

[avMutableVideoCompositionLayerInstruction setTransform:assetVideoTrack.preferredTransform atTime:kCMTimeZero];

avMutableVideoCompositionInstruction.layerInstructions = [NSArray arrayWithObject:avMutableVideoCompositionLayerInstruction];

videoComposition.instructions = [NSArray arrayWithObject:avMutableVideoCompositionInstruction];

}

NSFileManager* fileManager=[NSFileManager defaultManager];
BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:createPath];
if (blHave) {
[fileManager removeItemAtPath:createPath error:nil];
}

NSURL *mergeFileURL = [NSURL fileURLWithPath:createPath];
//        NSLog(@"starvideorecordVC: 345 outpath = %@",outpath);
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetMediumQuality];
exporter.outputURL = mergeFileURL;

exporter.videoComposition = videoComposition;
exporter.outputFileType = AVFileTypeMPEG4;
exporter.shouldOptimizeForNetworkUse = YES;
[exporter exportAsynchronouslyWithCompletionHandler:^{
NSLog(@" exporter%@",exporter.error);
if (exporter.status == AVAssetExportSessionStatusCompleted) {

dispatch_async(dispatch_get_main_queue(), ^{

_playBcgV.hidden = NO;

[self.view bringSubviewToFront:_playBcgV];

_mediaV.contentURL = mergeFileURL;

[_mediaV prepareToPlay];
[_mediaV play];

});
}
}];

});
}else{

_playBcgV.hidden = NO;

[self.view bringSubviewToFront:_playBcgV];

_mediaV.contentURL = [NSURL fileURLWithPath:_fileUrlArr[0]];

[_mediaV prepareToPlay];
[_mediaV play];
}

}

#pragma mark - -----------------获取摄像头设备---------------------

/**
*  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;
}

#pragma mark --------------------检查文件路径------------------
-(NSString *)checkPath{
NSFileManager* fileManager=[NSFileManager defaultManager];

NSString *pathDocuments = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *createPath = [NSString stringWithFormat:@"%@/myVidio/%@", pathDocuments,_fileName];

// 判断文件夹是否存在，如果不存在，则创建
if (![[NSFileManager defaultManager] fileExistsAtPath:createPath]) {
[fileManager createDirectoryAtPath:createPath withIntermediateDirectories:YES attributes:nil error:nil];
}

NSString *pathDocument = [NSString stringWithFormat:@"%@/%d.mp4",createPath,_fileNum];

BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:pathDocument];
if (blHave) {
[fileManager removeItemAtPath:pathDocument error:nil];
}

return pathDocument;

}

#pragma mark ---------------------创建控制按钮----------------------
-(void)createButton{

UIButton * recordBtn = [UIButton buttonWithType:UIButtonTypeCustom];

recordBtn.frame = CGRectMake(30, HEIGHT-100, WIDTH/3-40, 40);

[recordBtn setTitle:@"开始" forState:UIControlStateNormal];
[recordBtn setTitle:@"停止" forState:UIControlStateSelected];
recordBtn.tag = 100;
recordBtn.backgroundColor = [UIColor blackColor];

recordBtn.layer.cornerRadius = 20;
recordBtn.clipsToBounds = YES;

[recordBtn addTarget:self action:@selector(recordStartOrPause:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:recordBtn];

UIButton * finishBtn = [UIButton buttonWithType:UIButtonTypeCustom];

finishBtn.frame = CGRectMake(WIDTH/3+20, HEIGHT-100, WIDTH/3-40, 40);

[finishBtn setTitle:@"完成" forState:UIControlStateNormal];
finishBtn.backgroundColor = [UIColor blackColor];

finishBtn.layer.cornerRadius = 20;
finishBtn.clipsToBounds = YES;
[finishBtn addTarget:self action:@selector(finishBtnClick:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:finishBtn];

UIButton * clearBtn = [UIButton buttonWithType:UIButtonTypeCustom];

clearBtn.frame = CGRectMake(WIDTH/3 * 2 + 10, HEIGHT-100, WIDTH/3-40, 40);
[clearBtn setTitle:@"清空" forState:UIControlStateNormal];
clearBtn.backgroundColor = [UIColor blackColor];

clearBtn.layer.cornerRadius = 20;
clearBtn.clipsToBounds = YES;
[clearBtn addTarget:self action:@selector(clearBtnClick:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:clearBtn];

}

#pragma mark ---------------------创建播放视图----------------------

-(void)createPlayBcgV{
_playBcgV = [[UIView alloc]initWithFrame:CGRectMake(0, 0, WIDTH, HEIGHT)];

_playBcgV.backgroundColor = [UIColor blackColor];

_mediaV = [[MPMoviePlayerController alloc]init];

_mediaV.view.frame = CGRectMake(0, 0, WIDTH, HEIGHT-120);
_mediaV.view.autoresizingMask=UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;

[_playBcgV addSubview:_mediaV.view];

UIButton * hideBtn = [UIButton buttonWithType:UIButtonTypeCustom];

hideBtn.frame = CGRectMake(30, HEIGHT-100, WIDTH-60, 40);

[hideBtn setTitle:@"隐藏" forState:UIControlStateNormal];

hideBtn.backgroundColor = [UIColor whiteColor];
[hideBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
hideBtn.layer.cornerRadius = 20;
hideBtn.clipsToBounds = YES;

[hideBtn addTarget:self action:@selector(hideBtnClick:) forControlEvents:UIControlEventTouchUpInside];

[_playBcgV addSubview:hideBtn];

_playBcgV.hidden = YES;

[self.view addSubview:_playBcgV];

}
#pragma mark ---------------------隐藏播放控制器---------------------
-(void)hideBtnClick:(UIButton *)btn{
NSLog(@"隐藏");
[_mediaV stop];
_playBcgV.hidden = YES;

}

@end

链接：https://github.com/cwos111509sina/VideoRecordText.git