如何解决iOS中的视频定位问题 [英] How to fix video orientation issue in iOS

问题描述

我正在使用一个应用程序，用户从照片中选择视频并将其上传到服务器。由于我的服务器是.Net服务器，因此视频会轮换。我知道问题的原因可能与图像的情况相同（您可以参考我之前的答案 https://stackoverflow.com/ a / 10601175/1030951 ），所以我用谷歌搜索并获得了修复视频方向的代码，我从RayWenderlich.com获得了一个代码，并按照以下方式进行了修改。现在我的输出视频工作正常，但视频是静音。它播放但不播放音频。如果我错过了什么，请帮助我。

I am working with an app in which user picks video from Photos and uploads it to server. As my server is .Net server , the video gets rotated. I know the reason of problem is probably same as was in case of image (you may refer my earlier answer https://stackoverflow.com/a/10601175/1030951 ) , So i googled and got a code to fix video orientation , I got a code from RayWenderlich.com and modified in following way. Now my output video works fine but the video is mute. it plays but doesn't play audio. Kindly help me if I am missing something.

我传递的信息词典 - （void）imagePickerController：（UIImagePickerController *）picker didFinishPickingMediaWithInfo：（NSDictionary *）info 方法

- (void)fix:(NSDictionary*)pobjInfoDirectory withFileName:(NSString*)pstrOutputFileName
{
    firstAsset = [AVAsset assetWithURL:[pobjInfoDirectory objectForKey:UIImagePickerControllerMediaURL]];


    if(firstAsset !=nil)
    {
        //Create AVMutableComposition Object.This object will hold our multiple AVMutableCompositionTrack.
        AVMutableComposition* mixComposition = [[AVMutableComposition alloc] init];

        //VIDEO TRACK
        AVMutableCompositionTrack *firstTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
        [firstTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAsset.duration) ofTrack:[[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];

        AVMutableVideoCompositionInstruction * MainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];

                MainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, firstAsset.duration);

        //FIXING ORIENTATION//
        AVMutableVideoCompositionLayerInstruction *FirstlayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:firstTrack];

        AVAssetTrack *FirstAssetTrack = [[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

        UIImageOrientation FirstAssetOrientation_  = UIImageOrientationUp;

        BOOL  isFirstAssetPortrait_  = NO;

        CGAffineTransform firstTransform = FirstAssetTrack.preferredTransform;

        if(firstTransform.a == 0 && firstTransform.b == 1.0 && firstTransform.c == -1.0 && firstTransform.d == 0)
        {
            FirstAssetOrientation_= UIImageOrientationRight; isFirstAssetPortrait_ = YES;
        }        
        if(firstTransform.a == 0 && firstTransform.b == -1.0 && firstTransform.c == 1.0 && firstTransform.d == 0)
        {
            FirstAssetOrientation_ =  UIImageOrientationLeft; isFirstAssetPortrait_ = YES;
        }
        if(firstTransform.a == 1.0 && firstTransform.b == 0 && firstTransform.c == 0 && firstTransform.d == 1.0)
        {
            FirstAssetOrientation_ =  UIImageOrientationUp;
        }
        if(firstTransform.a == -1.0 && firstTransform.b == 0 && firstTransform.c == 0 && firstTransform.d == -1.0)
        {
            FirstAssetOrientation_ = UIImageOrientationDown;
        }

        CGFloat FirstAssetScaleToFitRatio = 320.0/FirstAssetTrack.naturalSize.width;

        if(isFirstAssetPortrait_)
        {
            FirstAssetScaleToFitRatio = 320.0/FirstAssetTrack.naturalSize.height;
            CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
            [FirstlayerInstruction setTransform:CGAffineTransformConcat(FirstAssetTrack.preferredTransform, FirstAssetScaleFactor) atTime:kCMTimeZero];
        }
        else
        {
            CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
            [FirstlayerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformConcat(FirstAssetTrack.preferredTransform, FirstAssetScaleFactor),CGAffineTransformMakeTranslation(0, 160)) atTime:kCMTimeZero];
        }
        [FirstlayerInstruction setOpacity:0.0 atTime:firstAsset.duration];

        MainInstruction.layerInstructions = [NSArray arrayWithObjects:FirstlayerInstruction,nil];;

        AVMutableVideoComposition *MainCompositionInst = [AVMutableVideoComposition videoComposition];
        MainCompositionInst.instructions = [NSArray arrayWithObject:MainInstruction];
        MainCompositionInst.frameDuration = CMTimeMake(1, 30);
        MainCompositionInst.renderSize = CGSizeMake(320.0, 480.0);

        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *myPathDocs =  [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"mergeVideo-%d.mov",arc4random() % 1000]];

        NSURL *url = [NSURL fileURLWithPath:myPathDocs];

        AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];

        exporter.outputURL=url;
        exporter.outputFileType = AVFileTypeQuickTimeMovie;
        exporter.videoComposition = MainCompositionInst;
        exporter.shouldOptimizeForNetworkUse = YES;
        [exporter exportAsynchronouslyWithCompletionHandler:^
         {
             dispatch_async(dispatch_get_main_queue(), ^{
                 [self exportDidFinish:exporter];
             });
         }];
    }
}

- (void)exportDidFinish:(AVAssetExportSession*)session
{
    if(session.status == AVAssetExportSessionStatusCompleted)
    {
        NSURL *outputURL = session.outputURL;
        ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];

        if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:outputURL])
        {
            if ([self.delegate respondsToSelector:@selector(videoExported)])
                [self.delegate videoExported];    
        }
    }       
    firstAsset = nil;
}

推荐答案

在<$之后添加此项c $ c> // VIDEO TRACK part

        //AUDIO TRACK
        AVMutableCompositionTrack *firstAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
        [firstAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAsset.duration) ofTrack:[[firstAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];

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