[iOS]短视频录制(新)

简单介绍

这篇文章是自己做短视频功能这几个月的一个总结，以下文字或代码有任何不妥的地方希望各位积极指出错误，并给出建议。

从短视频拍摄基本功能来说，我想应该有以下，美颜，水印，断点拍摄，编辑功能，编辑功能包含，滤镜添加，背景音乐添加，贴图贴纸添加，高质量压缩（视频降低码率）。针对这些功能，我会逐一介绍其实现方法。

使用到的第三方库：TZImagePickerController，GPUImage，SDAVAssetExportSession

demo效果图

文章末尾会附上demo地址

预览画面支持美颜切换，前后相机切换

录制中

暂停录制，支持断点回删

滤镜选择共8重

选择音乐

贴纸选择，可随意调整贴纸位置

预览发布页面，按各自实际app需求调整

录制功能实现

录制功能是基于GPUImageVideoCamera实现的：

相机初始化

videoCamera = [[GPUImageVideoCamera alloc] initWithSessionPreset:AVCaptureSessionPreset1280x720 cameraPosition:AVCaptureDevicePositionBack];

给相机添加滤镜

filter = [[LFGPUImageEmptyFilter alloc] init];  //这个滤镜是一个空滤镜

filteredVideoView = [[GPUImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; //创建预览画面

[videoCamera addTarget:filter];

[filter addTarget:filteredVideoView];

开起预览

[videoCamera startCameraCapture];  //启动相机

切换至美颜滤镜

[videoCamera removeAllTargets]; //移除其它滤镜

filter = [[GPUImageBeautifyFilter alloc] init];//美颜滤镜

[videoCamera addTarget:filter];

[filter addTarget:filteredVideoView];

视频录制以及断点续拍

断点续拍的实质就是把多个视频合并成同一视频

开始录制

movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(720.0, 1280.0)];

movieWriter.isNeedBreakAudioWhiter = YES;

movieWriter.encodingLiveVideo = YES;

movieWriter.shouldPassthroughAudio = YES;

[filter addTarget:movieWriter];

videoCamera.audioEncodingTarget = movieWriter;

[movieWriter startRecording];

暂停录制

暂停录制就是把视频先保存起来，并将视频地址保存在数组中，这样就能实现断点续拍。

[movieWriter finishRecording];

[filter removeTarget:movieWriter];

[urlArray addObject:[NSURL URLWithString:[NSString stringWithFormat:@"file://%@",pathToMovie]]];

拍摄完成后的合成操作以及水印添加

创建音视频合成体，以及视频通道容器，音频通道容器

[[AVMutableComposition alloc] init];

[mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio

preferredTrackID:kCMPersistentTrackID_Invalid];

[mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo

preferredTrackID:kCMPersistentTrackID_Invalid];

用AVAsset取出素材，并且分别取出音频轨道 与视频轨道按时间措添加至 上面创建的音视频容器中

AVAsset* asset = [AVURLAsset URLAssetWithURL:videosPathArray[i] options:options];

//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];

//向通道内加入视频步骤与上面音频的添加差不多

视频水印的添加，创建layer ，并将layer 添加AVMutableVideoComposition 这个对象中

视频导出，创建AVAssetExportSession 对象 ，并为其设置videoComposition属性，以此添加水印

//视频导出工具

AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition

presetName:AVAssetExportPreset1280x720];

exporter.videoComposition = videoComp;

导出方法 - (void)exportAsynchronouslyWithCompletionHandler:(void (^)(void))handler;

导出成功后进入下一个视频编辑页面

视频滤镜处理

创建视频预览，使用GPUImageMovie工具 并结合avPlayer

mainPlayer = [[AVPlayer alloc] init];

playerItem = [[AVPlayerItem alloc] initWithURL:videoURL];

[mainPlayer replaceCurrentItemWithPlayerItem:playerItem];

playerLayer = [AVPlayerLayer playerLayerWithPlayer:mainPlayer];

movieFile = [[GPUImageMovie alloc] initWithPlayerItem:playerItem];

movieFile.runBenchmark = YES; movieFile.playAtActualSpeed = YES;

//新建一个空白滤镜添加至 movieFile

filter = [[LFGPUImageEmptyFilter alloc] init];

_filtClassName = @"LFGPUImageEmptyFilter";

[movieFile addTarget:filter];

//视频预览容器view

_filterView = [[GPUImageView alloc] initWithFrame:self.view.bounds];

[self.view addSubview:_filterView];

[filter addTarget:_filterView];

开始预览方法：- (void)startProcessing;

//avplay开始播放

[mainPlayer play];

[movieFile startProcessing];

切换滤镜效果

[movieFile removeAllTargets];

//新建一个新的滤镜文件

filter = [[NSClassFromString(_filtClassName) alloc] init];

//将滤镜添加至 movieFile上

[movieFile addTarget:filter];

//重新添加预览容器view

[filter addTarget:_filterView];

生成带滤镜处理后的视频

//1.新建用于导出的MovieFile

endMovieFile = [[GPUImageMovie alloc] initWithURL:sampleURL];

endMovieFile.runBenchmark = YES;

endMovieFile.playAtActualSpeed = NO;

//2.给MovieFile添加滤镜

endFilter = [[NSClassFromString(_filtClassName) alloc] init];

[endMovieFile addTarget:endFilter];

//3.新建GPUImageMovieWriter写入类

movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:movieURL size:CGSizeMake(720.0, 1280.0)];

[endFilter  addTarget:movieWriter];

movieWriter.shouldPassthroughAudio = YES;

endMovieFile.audioEncodingTarget = movieWriter;

[endMovieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

//4.开始写入

[movieWriter startRecording];

[endMovieFile startProcessing];

[movieWriter setCompletionBlock:^{

//.完成后的逻辑处理

}];

音乐合成处理/贴图合成处理

此处方法原理 与第一页视频合成，水印处理基本相同。前者就是将音频素材 添加到音频轨道中， 后者还是视频layer上加layer；

视频的压缩处理

NSDictionary* options = @{AVURLAssetPreferPreciseDurationAndTimingKey:@YES};

AVAsset* asset = [AVURLAsset URLAssetWithURL:inputVideoUrl options:options];

NSArray* keys = @[@"tracks",@"duration",@"commonMetadata"];

[asset loadValuesAsynchronouslyForKeys:keys completionHandler:^{

SDAVAssetExportSession *compressionEncoder = [SDAVAssetExportSession.alloc initWithAsset:asset]; // provide inputVideo Url Here

compressionEncoder.outputFileType = AVFileTypeMPEG4;//文件输出格式

compressionEncoder.outputURL = outputVideoUrl; //文件输出地址

//视频参数配置

compressionEncoder.videoSettings = @

{

AVVideoCodecKey: AVVideoCodecH264,//编码方式

AVVideoWidthKey: @720,  //视频宽

AVVideoHeightKey: @1280,  //视频高

AVVideoCompressionPropertiesKey: @

{

//2000*1000  建议800*1000-5000*1000

//            AVVideoAverageBitRateKey: @2500000, // Give your bitrate here for lower size give low values

AVVideoAverageBitRateKey: _bit,//比特lv

AVVideoProfileLevelKey: AVVideoProfileLevelH264HighAutoLevel,

AVVideoAverageNonDroppableFrameRateKey: _frameRate,//fps

},

};

//音频参数配置

compressionEncoder.audioSettings = @

{

AVFormatIDKey: @(kAudioFormatMPEG4AAC),//编码方式

AVNumberOfChannelsKey: @2,//通道，双通道

AVSampleRateKey: @44100,//菜样率

AVEncoderBitRateKey: @128000,//编码比特lv

};

[compressionEncoder exportAsynchronouslyWithCompletionHandler:^

{

//处理成功

}];

}];

Demo传送门:https://github.com/doubleYang1020/DYVideoCamera