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IOS 视频压缩 视频旋转的矫正

来源:二三娱乐

最近的app项目中遇到了上传视频和图片的问题

上传视频的时候发现一个问题就是 有些视频在相册是方向正确的,但是上传到阿里云之后变得旋转了

就是针对这个问题把压缩和视频旋转一并说下

首先你需要提前获取到PHAsset文件(包含视频的那种)

phAsset; //提前获取

if (phAsset.mediaType == PHAssetMediaTypeVideo || phAsset.mediaSubtypes == PHAssetMediaSubtypePhotoLive) {

                PHVideoRequestOptions *options = [[PHVideoRequestOptions alloc] init];

                options.version = PHVideoRequestOptionsVersionOriginal;

                [[PHImageManager defaultManager] requestAVAssetForVideo:phAsset options:options resultHandler:^(AVAsset *asset, AVAudioMix *audioMix, NSDictionary *info) {

                    if ([asset isKindOfClass:[AVURLAsset class]]) {

                        AVURLAsset* urlAsset = (AVURLAsset*)asset;

                        NSURL *url = urlAsset.URL;

                        NSData *data = [NSData dataWithContentsOfURL:url];

                        NSInteger dataSizeNum = data.length /(1024);

                        NSLog(@"压缩前视频大小是多少::::%ldM", (long)dataSizeNum/1024);

                        }

                        NSNumber *number = [NSNumber numberWithInteger:dataSizeNum];

                        dispatch_async(dispatch_get_main_queue(), ^{

                            [MBProgressHUD showLoadHUDMsg:@"视频压缩中"];

                        });

//以下是视频压缩的代码

                        AVAssetExportSession * session = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetMediumQuality];

                        //优化网络

                        session.shouldOptimizeForNetworkUse = YES;

                        //转换后的格式

                        //拼接输出文件路径 为了防止同名 可以根据日期拼接名字 或者对名字进行MD5加密

                        NSString* path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"newVideo.mp4"];

                        //判断文件是否存在,如果已经存在删除

                        [[NSFileManager defaultManager] removeItemAtPath:path error:nil];

                        //设置输出路径

                        session.outputURL = [NSURL fileURLWithPath:path];

                        //设置输出类型  这里可以更改输出的类型 具体可以看文档描述

                        session.outputFileType = AVFileTypeMPEG4;

//判断旋转方向,对于没有旋转的不进行处理了

                       NSUInteger degrees = [weakSelf degressFromVideoFileWithAsset:asset];

                        if (degrees != 0) { //需要旋转

                            session.videoComposition = [weakSelf getVideoComposition:asset];//判断旋转并矫正

                        }

                        [session exportAsynchronouslyWithCompletionHandler:^{

                            //压缩完成

currentData = [NSData dataWithContentsOfURL:session.outputURL];

                            } else { //压缩失败

                                //                                    NSLog(@"-------压缩失败%@", session.error)

                    }];

}]

            }

//视频扶正
- (AVMutableVideoComposition *)getVideoComposition:(AVAsset *)asset{

    NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
    AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
    CGAffineTransform translateToCenter;
    CGAffineTransform mixedTransform;
    AVMutableVideoComposition *waterMarkVideoComposition = [AVMutableVideoComposition videoComposition];
    waterMarkVideoComposition.frameDuration = CMTimeMake(1, 30);
    NSUInteger degrees = [self degressFromVideoFileWithAsset:asset];
    if (degrees == 0) { //不需要旋转
    } else{
        if(degrees == 90){
            //顺时针旋转90°
            NSLog(@"视频旋转90度,home按键在左");
            translateToCenter = CGAffineTransformMakeTranslation(videoTrack.naturalSize.height, 0.0);
            mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI_2);
            waterMarkVideoComposition.renderSize = CGSizeMake(videoTrack.naturalSize.height,videoTrack.naturalSize.width);
           
        } else if(degrees == 180){
            //顺时针旋转180° NSLog(@"视频旋转180度,home按键在上");
            translateToCenter = CGAffineTransformMakeTranslation(videoTrack.naturalSize.width, videoTrack.naturalSize.height);
            mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI);
            waterMarkVideoComposition.renderSize = CGSizeMake(videoTrack.naturalSize.width,videoTrack.naturalSize.height);
           
        } else { //顺时针旋转270° NSLog(@"视频旋转270度,home按键在右");
            translateToCenter = CGAffineTransformMakeTranslation(0.0, videoTrack.naturalSize.width);
            mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI_2*3.0);
            waterMarkVideoComposition.renderSize = CGSizeMake(videoTrack.naturalSize.height,videoTrack.naturalSize.width);

        }
        AVMutableVideoCompositionInstruction *roateInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
        roateInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, [asset duration]);
        AVMutableVideoCompositionLayerInstruction *roateLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
        [roateLayerInstruction setTransform:mixedTransform atTime:kCMTimeZero];
        roateInstruction.layerInstructions = @[roateLayerInstruction];
        //将视频方向旋转加入到视频处理中
        waterMarkVideoComposition.instructions = @[roateInstruction];
    }
    return waterMarkVideoComposition;
}

//以下是判断方向的

-(NSUInteger)degressFromVideoFileWithAsset:(AVAsset*)asset {
    NSUInteger degress = 0;
    NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];
    if([tracks count] > 0) {
        AVAssetTrack *videoTrack = [tracks objectAtIndex:0];
        CGAffineTransform t = videoTrack.preferredTransform;
        if(t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0){
            // Portrait
            degress = 90;
        }else if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0){
            // PortraitUpsideDown
            degress = 270;
        }else if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0){
            // LandscapeRight
            degress = 0;
        }else if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0){
            // LandscapeLeft
            degress = 180;
        }
    }
    return degress;
   
}

如有不正之处,望各位大神指出。谢谢。

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