GPUimage 滤镜视频录制

本篇是基于落影的博客进行记录,用以学习.

要做的任务: 开启摄像头, 画面加了一个滤镜实时显示, 点击录制,对加了滤镜的视频进行保存,录制结束,将数据写入到相册中.

整体的流程是这样.用GPUimageVideoCamer 进行图像和音频的捕获,  视频通过滤镜处理,之后有两个流向;

1. 直接显示

 

    //初始化
    _videoCamer = [[GPUImageVideoCamera alloc]initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionBack];
    _videoCamer.outputImageOrientation = [UIApplication sharedApplication].statusBarOrientation;
    //因为要设置audioEncodingTarget, 所以提前把音频的输入和输出加入,不然第一帧会黑屏
    [_videoCamer addAudioInputsAndOutputs];
    
    //滤镜
    _filter = [[GPUImageSepiaFilter alloc]init];
    //显示图
    _filterView = [[GPUImageView alloc]initWithFrame:self.view.frame];
    self.view = _filterView;
    
    //形成滤镜链
    // 渲染后的视频
    //1. 用来在屏幕上显示图像
    //2. 通过GPUimageMovieWriter
    [_videoCamer addTarget:_filter];
    [_filter addTarget:_filterView];
    //启动开始捕捉画面
    [_videoCamer startCameraCapture];

2. 当录制时, 将图像传递给GPUimageMovieWriter;

- (void)onClick:(UIButton *)sender {
    NSString *pathToMovie = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Movie4.m4v"];
    NSURL *movieUrl = [NSURL fileURLWithPath:pathToMovie];
    if ([sender.currentTitle isEqualToString:@"录制"]) { //开始录制,将捕获的数据i
        [sender setTitle:@"结束" forState:UIControlStateNormal];
        //如果存在文件,AVAssetWrite会有异常,删除旧文件
        unlink([pathToMovie UTF8String]);
        
        //这个是用来录制视频(其实是将此时相机捕获的数据保存起来, 只是还没有写入到文件系统里)
        _movieWriter = [[GPUImageMovieWriter alloc]initWithMovieURL:movieUrl size:CGSizeMake(480.0, 640.0)];
        _movieWriter.encodingLiveVideo = YES;
        
        //滤镜之后
        [_filter addTarget:_movieWriter];
        //这里设置了audioEncodingTarget(音频编码目标) , 捕获的音频会给设定好的目标(_movieWriter),将音频数据保存 如果不提前添加音频的输入输出,会导致第一帧黑屏
        _videoCamer.audioEncodingTarget = _movieWriter;
        
        //开始录制  保存的时候 也是滤镜处理之后的图像  一个滤镜可以有两个出口
        [_movieWriter startRecording];
        
        _labelTime = 0;
        _label.hidden = NO;
        [self onTimer:nil];
        _mTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(onTimer:) userInfo:nil repeats:YES];
    } else {
        [sender setTitle:@"录制" forState:UIControlStateNormal];
        _label.hidden = YES;
        if (_mTimer) {
            [_mTimer invalidate];
        }
        
        [_filter removeTarget:_movieWriter];
        _videoCamer.audioEncodingTarget = nil;
        [_movieWriter finishRecording];
        
        ALAssetsLibrary *liabrary = [[ALAssetsLibrary alloc]init];
        if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(pathToMovie)) {
            [liabrary writeVideoAtPathToSavedPhotosAlbum:movieUrl completionBlock:^(NSURL *assetURL, NSError *error) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    UIAlertAction *action = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil];
                    UIAlertController *con;
                    if (error) {
                        con = [UIAlertController alertControllerWithTitle:@"操作提示" message:@"视频保存失败" preferredStyle:UIAlertControllerStyleAlert];
              
                    }else{
                        con = [UIAlertController alertControllerWithTitle:@"操作提示" message:@"视频保存成功" preferredStyle:UIAlertControllerStyleAlert];
                    }
                    [con addAction:action];
                                  [self.navigationController presentViewController:con animated:YES completion:nil];
                });
                
            }];
        }
    }
}