Question

我正在将视频与视频和音频合并到视频中。在带视频盒的视频中工作正常但是当音频文件合并给黑屏时。我不知道这个代码我会出错什么

-(void)mergeAllMediaAtTime:(NSMutableArray*)startTimeArray {

NSURL *firstURL = [NSURL fileURLWithPath:[urlArray objectAtIndex:counter]];
firstAsset = [AVAsset assetWithURL:firstURL];

NSString* videoDirPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Crop Videos"];
NSString* fileName = [VideoAndAudioNameArray objectAtIndex:counter];
NSString *pSecondVideoPath = [videoDirPath stringByAppendingPathComponent:fileName];
NSURL *secondURL = [NSURL fileURLWithPath:pSecondVideoPath];


secondAsset = [AVAsset assetWithURL:secondURL];
if(firstAsset !=nil && secondAsset!=nil)
{
    AVVideoComposition *origionalComposition = [AVVideoComposition videoCompositionWithPropertiesOfAsset:firstAsset];

    //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];
    AVAssetTrack* track = [[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    [firstTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, firstAsset.duration) ofTrack:track atTime:kCMTimeZero error:nil];


    int time = [[startTimeArray objectAtIndex:counter] intValue];

    CMTime pTime = CMTimeMake(time, 1);

    ///////////////////////

    AVMutableCompositionTrack *secondTrack;
    if ([[fileName pathExtension] isEqualToString:@"mov"])
    {
        secondTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

        [secondTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAsset.duration) ofTrack:[[secondAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:pTime error:nil];
    }
    // If Audio file

    else
    {
        secondTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
        [secondTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAsset.duration) ofTrack:[[secondAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:pTime error:nil];
        NSLog(@"Audio file's Merging");          
    }


    /****** First Video *********/

    AVMutableVideoCompositionInstruction * MainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    MainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, firstAsset.duration);

    MainInstruction.backgroundColor = [[UIColor clearColor] CGColor];

    //FIXING ORIENTATION//
    AVMutableVideoCompositionLayerInstruction *FirstlayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:firstTrack];
    AVAssetTrack *FirstAssetTrack = [[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

    [FirstlayerInstruction setTransform:FirstAssetTrack.preferredTransform atTime:kCMTimeZero];
    [FirstlayerInstruction setOpacity:0.0 atTime:firstAsset.duration];

    if ([[fileName pathExtension] isEqualToString:@"mov"])
    {
        /****** Second Video *********/

        AVMutableVideoCompositionLayerInstruction *SecondlayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:secondTrack];
        AVAssetTrack *SecondAssetTrack = [[secondAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

        [SecondlayerInstruction setOpacity:1.0 atTime:pTime];

        UIImageOrientation SecondAssetOrientation_  = UIImageOrientationUp;
        BOOL  isSecondAssetPortrait_  = NO;
        CGAffineTransform secondTransform = SecondAssetTrack.preferredTransform;
        if(secondTransform.a == 0 && secondTransform.b == 1.0 && secondTransform.c == -1.0 && secondTransform.d == 0)  {SecondAssetOrientation_= UIImageOrientationRight; isSecondAssetPortrait_ = YES;}
        if(secondTransform.a == 0 && secondTransform.b == -1.0 && secondTransform.c == 1.0 && secondTransform.d == 0)  {SecondAssetOrientation_ =  UIImageOrientationLeft; isSecondAssetPortrait_ = YES;}
        if(secondTransform.a == 1.0 && secondTransform.b == 0 && secondTransform.c == 0 && secondTransform.d == 1.0)   {SecondAssetOrientation_ =  UIImageOrientationUp;}
        if(secondTransform.a == -1.0 && secondTransform.b == 0 && secondTransform.c == 0 && secondTransform.d == -1.0) {SecondAssetOrientation_ = UIImageOrientationDown;}
        CGFloat SecondAssetScaleToFitRatioOfWidth = nRenderWidth/SecondAssetTrack.naturalSize.width;
        if(isSecondAssetPortrait_)
        {
            CGFloat SecondAssetScaleToFitRatioOfHeight = nRenderWidth/SecondAssetTrack.naturalSize.height;
            CGAffineTransform SecondAssetScaleFactor = CGAffineTransformMakeScale(SecondAssetScaleToFitRatioOfWidth,SecondAssetScaleToFitRatioOfHeight);
            [SecondlayerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformMakeScale(1.0f,1.0f), SecondAssetScaleFactor) atTime:kCMTimeZero];
            //CGAffineTransformConcat(CGAffineTransformMakeScale(1.0f,1.0f), SecondAssetScaleFactor)

        }
        else
        {
            CGFloat SecondAssetScaleToFitRatioOfWidth = nRenderWidth/SecondAssetTrack.naturalSize.width;
            CGFloat SecondAssetScaleToFitRatioOfHeight = nRenderWidth/SecondAssetTrack.naturalSize.height;

            CGAffineTransform SecondAssetScaleFactor = CGAffineTransformMakeScale(SecondAssetScaleToFitRatioOfWidth,SecondAssetScaleToFitRatioOfHeight);
            //[SecondlayerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformConcat(SecondAssetTrack.preferredTransform, SecondAssetScaleFactor),CGAffineTransformMakeTranslation(0, 160)) atTime:firstAsset.duration];

            [SecondlayerInstruction setTransform:CGAffineTransformConcat(SecondAssetScaleFactor ,CGAffineTransformMakeTranslation(1, 1)) atTime:kCMTimeZero];
            //CGAffineTransformConcat(CGAffineTransformMakeScale(1.0f,1.0f),CGAffineTransformMakeTranslation(0, 100))
        }

        [SecondlayerInstruction setOpacity:0.0 atTime:CMTimeAdd(pTime, secondAsset.duration)];
         MainInstruction.layerInstructions = [NSArray arrayWithObjects:SecondlayerInstruction, FirstlayerInstruction,nil];

    }


    AVMutableVideoComposition *MainCompositionInst = [AVMutableVideoComposition videoComposition];
    MainCompositionInst.instructions = [NSArray arrayWithObject:MainInstruction];
    MainCompositionInst.frameDuration = origionalComposition.frameDuration;
    MainCompositionInst.renderScale = 1.0;
    MainCompositionInst.renderSize = CGSizeMake(nRenderWidth, nRenderHeight);


    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];
    [urlArray addObject:myPathDocs];
    AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetMediumQuality];
    exporter.outputURL=url;
    exporter.outputFileType = AVFileTypeQuickTimeMovie;
    exporter.videoComposition = MainCompositionInst;
    exporter.shouldOptimizeForNetworkUse = YES;
    [exporter exportAsynchronouslyWithCompletionHandler:^
     {
         dispatch_async(dispatch_get_main_queue(), ^{

             [self exportDidFinish:exporter];

             }

         });
     }];
}

}

Answer 1

在这种情况下，您可以从视频帧的末尾开始播放音频。您可以使用“atTime：kCMTimeZero”。

即：如下所示（下面的代码）

else
{
    secondTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    [secondTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, secondAsset.duration) ofTrack:[[secondAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];
    NSLog(@"Audio file's Merging");          
}

如何合并音频和视频？

1 个答案: