Question

我有这个代码为我的资产添加一个叠加层并将其导出到一个URL：

AVAsset *videoAsset = editableAsset;
AVMutableComposition* mixComposition = [AVMutableComposition composition];

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] lastObject];
AVMutableCompositionTrack *compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipVideoTrack atTime:kCMTimeZero error:nil];

if ([videoAsset tracksWithMediaType:AVMediaTypeAudio].count != 0) {
    AVAssetTrack *clipAudioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
    [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipAudioTrack atTime:kCMTimeZero error:nil];
}

[compositionVideoTrack setPreferredTransform:[[[videoAsset tracksWithMediaType:AVMediaTypeVideo] lastObject] preferredTransform]];

CGSize sizeOfVideo = [videoAsset naturalSize];

CALayer *layerCa = [CALayer layer];
layerCa.contents = (id)[UIImage imageNamed:@"Overlay.png"].CGImage;
layerCa.frame = CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
layerCa.opacity = 1.0;

CALayer *parentLayer=[CALayer layer];
CALayer *videoLayer=[CALayer layer];
parentLayer.frame=CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
videoLayer.frame=CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:layerCa];

AVMutableVideoComposition *videoComposition=[AVMutableVideoComposition videoComposition] ;
videoComposition.frameDuration=CMTimeMake(1, 30);
videoComposition.renderSize = sizeOfVideo;
videoComposition.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];
videoComposition.instructions = [NSArray arrayWithObject: instruction];

NSString* docFolder = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString* outputPath = [docFolder stringByAppendingPathComponent:@"output.mov"];
if ([[NSFileManager defaultManager] fileExistsAtPath:outputPath])
    [[NSFileManager defaultManager] removeItemAtPath:outputPath error:nil];

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:editableAsset presetName:AVAssetExportPresetHighestQuality];
exportSession.videoComposition = videoComposition;
exportSession.outputURL = [NSURL fileURLWithPath:outputPath];
exportSession.outputFileType = AVFileTypeQuickTimeMovie;
[exportSession exportAsynchronouslyWithCompletionHandler:^{

    dispatch_async(dispatch_get_main_queue(), ^{

        assetURL = [NSURL fileURLWithPath:outputPath];

    });

}];

奇怪的想法：它倾斜AVAsset，我得到一个风景视频而不是肖像。但我没有任何代码可以改变方向。你能解释一下吗？

使用AVAssetExportSession进行AVAsset倾斜

0 个答案: