iphone - 如何使用 CAAffineTranslation 或任何其他方式将视频方向从横向设置为纵向？

Question

我正在使用 AVMutableComposition 合并视频并且视频被合并。但是视频在合并后被存储在横向（这是 AVAsset 的默认模式）中。所以我希望视频只能在纵向模式下修复......有没有将视频方向设置为纵向模式的方法。提前感谢

这是我用于合并视频的代码

NSArray *arrVideoUrl=[objApp.dictSelectedVideos allKeys];
NSMutableArray *arrVideoAsset=[[NSMutableArray alloc]init];
for (int i=0; i<objApp.dictSelectedVideos.count; i++) {
      AVURLAsset *video=[[AVURLAsset alloc]initWithURL:[arrVideoUrl objectAtIndex:i] options:nil];
    [arrVideoAsset addObject:video];
}
AVURLAsset *music_track=[[AVURLAsset alloc]initWithURL:songUrl options:nil];
//to mix up the media items
AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];
//Setting Audio track
AVMutableCompositionTrack *AudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
//setting the track to add the videos
AVMutableCompositionTrack *firstTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVURLAsset *tempVideo1=[arrVideoAsset objectAtIndex:0];
AVURLAsset *tempVideo2=[arrVideoAsset objectAtIndex:1];
[firstTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, tempVideo1.duration)ofTrack:[[tempVideo1 tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:kCMTimeZero error:nil];
if (arrVideoUrl.count==1)
{
    [AudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, CMTimeAdd(kCMTimeZero, tempVideo2.duration))ofTrack:[[music_track tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];
}
else{
        for (int j=1; j<=arrVideoAsset.count-1; j++)
     {
        AVURLAsset *tempVideoNext=[arrVideoAsset objectAtIndex:j];
        AVURLAsset *tempVideoPrev=[arrVideoAsset objectAtIndex:j-1];
        [firstTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, tempVideoNext.duration)ofTrack:[[tempVideoNext tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:tempVideoPrev.duration error:nil];

    }
    [AudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, CMTimeAdd(tempVideo1.duration, tempVideo2.duration))ofTrack:[[music_track tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:nil];

}

Answer 1

我还找到了另一个解决方案...如果您想将方向从横向更改为纵向...使用此代码

AVMutableVideoComposition *videoComp = [AVMutableVideoComposition videoComposition];
videoComp.renderSize = videoSize;
videoComp.frameDuration = CMTimeMake(1, 30);
videoComp.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];

AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mixComposition duration]);
AVAssetTrack *videoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction];
videoComp.instructions = [NSArray arrayWithObject: instruction];

UIImageOrientation videoAssetOrientation_  = UIImageOrientationUp;
BOOL  isVideoAssetPortrait_  = NO;
CGAffineTransform videoTransform = clipVideoTrack.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;}

CGFloat FirstAssetScaleToFitRatio = 320.0 / clipVideoTrack.naturalSize.width;

if(isVideoAssetPortrait_) {
    FirstAssetScaleToFitRatio = 320.0/clipVideoTrack.naturalSize.height;
    CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
    [layerInstruction setTransform:CGAffineTransformConcat(clipVideoTrack.preferredTransform, FirstAssetScaleFactor) atTime:kCMTimeZero];
}else{
    CGAffineTransform FirstAssetScaleFactor = CGAffineTransformMakeScale(FirstAssetScaleToFitRatio,FirstAssetScaleToFitRatio);
    [layerInstruction setTransform:CGAffineTransformConcat(CGAffineTransformConcat(clipVideoTrack.preferredTransform, FirstAssetScaleFactor),CGAffineTransformMakeTranslation(0, 160)) atTime:kCMTimeZero];
}

// [layerInstruction setOpacity:0.0 atTime:kCMTimeZero];

AVAssetExportSession *assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];//AVAssetExportPresetPassthrough
assetExport.videoComposition = videoComp;