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ios 通过AVFoundation给视频添加字幕

ios 通过AVFoundation给视频添加字幕

作者: 愛我你就抱抱我 | 来源:发表于2017-04-28 17:59 被阅读0次

    直接上代码

    +(void)addSRTWithSRTArr:(NSArray *)srtArr toVideoURL:(NSURL *)videoUrl complettion:(void (^)(NSURL *))completion
    
    {
        NSURL *outPutUrl;
        
        
        //1 创建AVAsset实例 AVAsset包含了video的所有信息 self.videoUrl输入视频的路径
        AVAsset *videoAsset = [AVAsset assetWithURL:videoUrl];
        //2 创建AVMutableComposition实例. apple developer 里边的解释 【AVMutableComposition is a mutable subclass of AVComposition you use when you want to create a new composition from existing assets. You can add and remove tracks, and you can add, remove, and scale time ranges.】
        AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];
        
        //3 视频通道  工程文件中的轨道,有音频轨、视频轨等,里面可以插入各种对应的素材
        AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
                                                                            preferredTrackID:kCMPersistentTrackID_Invalid];
        //把视频轨道数据加入到可变轨道中 这部分可以做视频裁剪TimeRange
        [videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                            ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject]
                             atTime:kCMTimeZero error:nil];
        
        //3.1 AVMutableVideoCompositionInstruction 视频轨道中的一个视频,可以缩放、旋转等
        AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
        mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration);
        
        // 3.2 AVMutableVideoCompositionLayerInstruction 一个视频轨道,包含了这个轨道上的所有视频素材
        AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
        AVAssetTrack *videoAssetTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject];
        UIImageOrientation videoAssetOrientation_  = UIImageOrientationUp;
        BOOL isVideoAssetPortrait_  = NO;
        CGAffineTransform videoTransform = videoAssetTrack.preferredTransform;
        if (videoTransform.a == 0 && videoTransform.b == 1.0 && videoTransform.c == -1.0 && videoTransform.d == 0) {
            videoAssetOrientation_ = UIImageOrientationRight;
            isVideoAssetPortrait_ = YES;
        }
        if (videoTransform.a == 0 && videoTransform.b == -1.0 && videoTransform.c == 1.0 && videoTransform.d == 0) {
            videoAssetOrientation_ =  UIImageOrientationLeft;
            isVideoAssetPortrait_ = YES;
        }
        if (videoTransform.a == 1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == 1.0) {
            videoAssetOrientation_ =  UIImageOrientationUp;
        }
        if (videoTransform.a == -1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == -1.0) {
            videoAssetOrientation_ = UIImageOrientationDown;
        }
        [videolayerInstruction setTransform:videoAssetTrack.preferredTransform atTime:kCMTimeZero];
        [videolayerInstruction setOpacity:0.0 atTime:videoAsset.duration];
        
        // 3.3 - Add instructions
        mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];
        //AVMutableVideoComposition:管理所有视频轨道,可以决定最终视频的尺寸,裁剪需要在这里进行
        AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
        
        CGSize naturalSize;
        if(isVideoAssetPortrait_){
            naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
        } else {
            naturalSize = videoAssetTrack.naturalSize;
        }
        
        float renderWidth, renderHeight;
        renderWidth = naturalSize.width;
        renderHeight = naturalSize.height;
        mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);
        mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
        mainCompositionInst.frameDuration = CMTimeMake(1, 30);
        
        //加水印
        // videoLayer是视频layer,parentLayer是最主要的,videoLayer和字幕,贴纸的layer都要加在该layer上
        CALayer *parentLayer = [CALayer layer];
        CALayer *videoLayer = [CALayer layer];
        parentLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight);
        videoLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight);
        [parentLayer addSublayer:videoLayer];
        for (SrtModel *srtModel in srtArr) {
            UILabel *subtitleLabel = [[UILabel alloc]initWithFrame:srtModel.rect];
            subtitleLabel.text = srtModel.title;
            subtitleLabel.textColor = srtModel.textColor;
            subtitleLabel.font = [UIFont fontWithName:srtModel.fontName size:srtModel.fontSize];
            // 这个是透明度动画主要是使在插入的才显示,其它时候都是不显示的
            subtitleLabel.layer.opacity = 0;
            CABasicAnimation *opacityAnim = [CABasicAnimation animationWithKeyPath:@"opacity"];
            opacityAnim.fromValue = [NSNumber numberWithFloat:1];
            opacityAnim.toValue = [NSNumber numberWithFloat:1];
            opacityAnim.removedOnCompletion = NO;
            
            CABasicAnimation *rotationAnimation;
            switch (srtModel.animationType) {
                case 0:
                    
                    break;
                case 1:
                    rotationAnimation = [SubTitleAnimation moveAnimationWithFromPosition:CGPointMake(subtitleLabel.layer.position.x + 100, subtitleLabel.layer.position.y) toPosition:subtitleLabel.layer.position];
                    break;
                case 2:
                    rotationAnimation = [SubTitleAnimation moveAnimationWithFromPosition:CGPointMake(subtitleLabel.layer.position.x, subtitleLabel.layer.position.y + 50) toPosition:subtitleLabel.layer.position];
                    break;
                case 3:
                    rotationAnimation = [SubTitleAnimation narrowIntoAnimation];
                    break;
                case 4:
                    rotationAnimation = [SubTitleAnimation fadeInAnimation];
                    break;
                case 5:
                    rotationAnimation = [SubTitleAnimation transformAnimation];
                    break;
                    
                default:
                    break;
            }
            CAAnimationGroup *groupAnimation = [CAAnimationGroup animation];
            groupAnimation.animations = [NSArray arrayWithObjects:opacityAnim, rotationAnimation, nil];
            if (CMTimeGetSeconds(srtModel.insertTime.start) == 0) {
                groupAnimation.beginTime = 0.01;
            }else {
                groupAnimation.beginTime = CMTimeGetSeconds(srtModel.insertTime.start);
            }
            groupAnimation.duration = CMTimeGetSeconds(srtModel.insertTime.duration);
            
            [subtitleLabel.layer addAnimation:groupAnimation forKey:nil];
            [parentLayer addSublayer:subtitleLabel.layer];
        }
        
        mainCompositionInst.animationTool = [AVVideoCompositionCoreAnimationTool
                                     videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
        
        
        
        
        
        // 4 - 输出路径
        
        NSString *documentsDirectory = [self mp4FilePath];
        NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:
                                 [NSString stringWithFormat:@"v_%@.mp4",[NSString dateToIDstring:[NSDate date]]]];
        outPutUrl = [NSURL fileURLWithPath:myPathDocs];
        
        // 5 - 视频文件输出
        AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition
                                                                          presetName:AVAssetExportPresetHighestQuality];
        exporter.outputURL = outPutUrl;
        exporter.outputFileType = AVFileTypeMPEG4;
        exporter.shouldOptimizeForNetworkUse = YES;
        exporter.videoComposition = mainCompositionInst;
        [exporter exportAsynchronouslyWithCompletionHandler:^{
            dispatch_async(dispatch_get_main_queue(), ^{
                //这里是输出视频之后的操作,做你想做的
                NSLog(@"完事了-----%f",[self getRealVideoAllTimeWith:outPutUrl]);
                completion(outPutUrl);
                
            });
        }];
    
    
    }
    
    

    如需详细代码,请留言,有任何问题请指正,谢谢!

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