一、前沿
- 项目需要，实现录制无声小视频，在无声小视频的基础上，再录制声音。
二、总体步骤
- 录制无声小视频(有声无声可选)
- 播放录制的小视频
- 实现录音功能，录音的音频长度等于小视频的视频长度
- 实现把音频加入到小视频当中。(原视频如果有声音的话，是否保留原来的视频声音，即加入的音频为背景音乐)
三、录制视频
步骤
- 创建捕捉会话
- 设置视频的输入
- 设置音频的输入
- 输出源设置,这里视频，音频数据会合并到一起输出，在代理方法中可以单独拿到视频或者音频数据，给AVCaptureMovieFileOutput指定路径，开始录制之后就会向这个路径写入数据
- 添加视频预览层
- 开始采集数据，这个时候还没有写入数据，用户点击录制后就可以开始写入数据
步骤 1 :创建捕捉会话
self.session = [[AVCaptureSession alloc] init];
if ([_session canSetSessionPreset:AVCaptureSessionPreset640x480]) {
//设置分辨率
_session.sessionPreset=AVCaptureSessionPreset640x480;
}
步骤 2 :设置视频的输入
- (void)setUpVideo
{
// 1.1 获取视频输入设备(摄像头)
AVCaptureDevice *videoCaptureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置摄像头
// 视频 HDR (高动态范围图像)
// videoCaptureDevice.videoHDREnabled = YES;
// 设置最大，最小帧速率
//videoCaptureDevice.activeVideoMinFrameDuration = CMTimeMake(1, 60);
// 1.2 创建视频输入源
NSError *error=nil;
self.videoInput= [[AVCaptureDeviceInput alloc] initWithDevice:videoCaptureDevice error:&error];
// 1.3 将视频输入源添加到会话
if ([self.session canAddInput:self.videoInput]) {
[self.session addInput:self.videoInput];
}
}
步骤 3 :设置音频的输入
// 2.1 获取音频输入设备
AVCaptureDevice *audioCaptureDevice=[[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
NSError *error=nil;
// 2.2 创建音频输入源
self.audioInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioCaptureDevice error:&error];
// 2.3 将音频输入源添加到会话
if ([self.session canAddInput:self.audioInput]) {
[self.session addInput:self.audioInput];
}
步骤 4 :输出源设置
- (void)setUpFileOut
{
// 3.1初始化设备输出对象，用于获得输出数据
self.FileOutput=[[AVCaptureMovieFileOutput alloc]init];
// 3.2设置输出对象的一些属性
AVCaptureConnection *captureConnection=[self.FileOutput connectionWithMediaType:AVMediaTypeVideo];
//设置防抖
//视频防抖 是在 iOS 6 和 iPhone 4S 发布时引入的功能。到了 iPhone 6，增加了更强劲和流畅的防抖模式，被称为影院级的视频防抖动。相关的 API 也有所改动 (目前为止并没有在文档中反映出来，不过可以查看头文件）。防抖并不是在捕获设备上配置的，而是在 AVCaptureConnection 上设置。由于不是所有的设备格式都支持全部的防抖模式，所以在实际应用中应事先确认具体的防抖模式是否支持：
if ([captureConnection isVideoStabilizationSupported ]) {
captureConnection.preferredVideoStabilizationMode=AVCaptureVideoStabilizationModeAuto;
}
//预览图层和视频方向保持一致
captureConnection.videoOrientation = [self.previewlayer connection].videoOrientation;
// 3.3将设备输出添加到会话中
if ([_session canAddOutput:_FileOutput]) {
[_session addOutput:_FileOutput];
}
}
步骤 5 :添加视频预览层
- (void)setUpPreviewLayerWithType:(ATVideoViewType )type
{
CGRect rect = CGRectZero;
switch (type) {
case Type1X1:
rect = CGRectMake(0, 0, kScreenWidth, kScreenWidth);
break;
case Type4X3:
rect = CGRectMake(0, 0, kScreenWidth, kScreenWidth*4/3);
break;
case TypeFullScreen:
rect = [UIScreen mainScreen].bounds;
break;
default:
rect = [UIScreen mainScreen].bounds;
break;
}
self.previewlayer.frame = rect;
[_superView.layer insertSublayer:self.previewlayer atIndex:0];
}
步骤 6 :开始采集数据
[self.session startRunning];
四、播放视频
步骤
步骤 1 :创建播放器
self.videoPlayer = [[MPMoviePlayerController alloc] init];
[self.videoPlayer.view setFrame:self.view.bounds];
self.videoPlayer.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self.view addSubview:self.videoPlayer.view];
[self.videoPlayer prepareToPlay];
self.videoPlayer.controlStyle = MPMovieControlStyleNone;
self.videoPlayer.shouldAutoplay = YES;
self.videoPlayer.repeatMode = MPMovieRepeatModeOne;
步骤 2 :设置文件播放路径
self.videoPlayer.contentURL = self.videoUrl;
[self.videoPlayer play];
步骤 3 :监听事件
//播放完成
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(captureFinished:) name:MPMoviePlayerThumbnailImageRequestDidFinishNotification object:nil];
//播放状态发生改变
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(stateChanged) name:MPMoviePlayerPlaybackStateDidChangeNotification object:nil];
五、录制录音
步骤
- 创建捕捉会话
- 设置采样参数(音频格式，质量等)
- 初始化对象
- 实现录音
步骤 1 :创建捕捉会话
AVAudioSession *session =[AVAudioSession sharedInstance];
NSError *sessionError;
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:&sessionError];
if (session != nil) {
[session setActive:YES error:nil];
}
self.session = session;
步骤 2 :设置采样参数(音频格式，质量等)
//设置参数
NSDictionary *recordSetting = [[NSDictionary alloc] initWithObjectsAndKeys:
//采样率 8000/11025/22050/44100/96000（影响音频的质量）
[NSNumber numberWithFloat: 8000.0],AVSampleRateKey,
// 音频格式
[NSNumber numberWithInt: kAudioFormatLinearPCM],AVFormatIDKey,
//采样位数 8、16、24、32 默认为16
[NSNumber numberWithInt:16],AVLinearPCMBitDepthKey,
// 音频通道数 1 或 2
[NSNumber numberWithInt: 1], AVNumberOfChannelsKey,
//录音质量
[NSNumber numberWithInt:AVAudioQualityHigh],AVEncoderAudioQualityKey,
nil];
步骤 3 :初始化对象
_recorder = [[AVAudioRecorder alloc] initWithURL:self.recordFileUrl settings:recordSetting error:nil];
if (_recorder) {
_recorder.meteringEnabled = YES;
[_recorder prepareToRecord];
[_recorder record];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(60 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self stopRecord];
});
}
步骤 4 :实现录音
[_recorder prepareToRecord];
[_recorder record];
六、视频合成
参数:
@param assetURL 原始视频路径
@param BGMPath 背景音乐路径
@param needOriginalVoice 是否添加原视频的声音
@param videoVolume 视频音量
@param BGMVolume 背景音乐音量
@param completionHandle 合成后的回调
+ (void)editVideoSynthesizeVieoPath:(NSURL *)assetURL BGMPath:(NSURL *)BGMPath needOriginalVoice:(BOOL)needOriginalVoice videoVolume:(CGFloat)videoVolume BGMVolume:(CGFloat)BGMVolume complition:(void (^)(NSURL *outputPath,BOOL isSucceed)) completionHandle{
// 素材
AVAsset *asset = [AVAsset assetWithURL:assetURL];
AVAsset *audioAsset = [AVAsset assetWithURL:BGMPath];
CMTime duration = asset.duration;
CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero, duration);
// 分离素材
AVAssetTrack *videoAssetTrack = [[asset tracksWithMediaType:AVMediaTypeVideo]objectAtIndex:0];//视频素材
AVAssetTrack *audioAssetTrack = [[audioAsset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];// 背景音乐音频素材
// 创建编辑环境
AVMutableComposition *composition = [[AVMutableComposition alloc]init];
// 视频素材加入视频轨道
AVMutableCompositionTrack *videoCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
[videoCompositionTrack insertTimeRange:video_timeRange ofTrack:videoAssetTrack atTime:kCMTimeZero error:nil];
// 音频素材加入音频轨道
AVMutableCompositionTrack *audioCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[audioCompositionTrack insertTimeRange:video_timeRange ofTrack:audioAssetTrack atTime:kCMTimeZero error:nil];
// audioCompositionTrack.preferredVolume = 0;
// 是否加入视频原声
AVMutableCompositionTrack *originalAudioCompositionTrack = nil;
if (needOriginalVoice) {
AVAssetTrack *originalAudioAssetTrack = [[asset tracksWithMediaType:AVMediaTypeAudio]objectAtIndex:0];
originalAudioCompositionTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
[originalAudioCompositionTrack insertTimeRange:video_timeRange ofTrack:originalAudioAssetTrack atTime:kCMTimeZero error:nil];
}
// 创建导出素材类
AVAssetExportSession *exporter = [[AVAssetExportSession alloc]initWithAsset:composition presetName:AVAssetExportPresetMediumQuality];
// 设置输出路径
NSURL *outputPath = [self exporterPath];
exporter.outputURL = outputPath;
exporter.outputFileType = AVFileTypeQuickTimeMovie;//指定输出格式
exporter.shouldOptimizeForNetworkUse= YES;
// 音量控制
exporter.audioMix = [self buildAudioMixWithVideoTrack:originalAudioCompositionTrack VideoVolume:videoVolume BGMTrack:audioCompositionTrack BGMVolume:BGMVolume atTime:kCMTimeZero];
[exporter exportAsynchronouslyWithCompletionHandler:^{
switch ([exporter status]) {
case AVAssetExportSessionStatusFailed: {
NSLog(@"合成失败：%@",[[exporter error] description]);
completionHandle(outputPath,NO);
} break;
case AVAssetExportSessionStatusCancelled: {
completionHandle(outputPath,NO);
} break;
case AVAssetExportSessionStatusCompleted: {
completionHandle(outputPath,YES);
} break;
default: {
completionHandle(outputPath,NO);
} break;
}
}];
}
七、总结
