我正在尝试使用iOS 4.3上的AVMutableComposition,AVMutableVideoComposition和AVVideoCompositionCoreAnimationTool将CALayer烘焙成纵向模式视频(导出时)。这一切都在景观中起作用。但是,如果我以纵向捕捉视频,AVVideoCompositionCoreAnimationTool将忽略视频轨道上的变换。也就是说,对于纵向模式视频,我将AVMutableCompositionTrack.preferredTransform设置为原始资产视频轨道中的preferredTransform值。只要我不使用AVVideoCompositionCoreAnimationTool,这就可以了,视频以纵向模式显示。但是,只要我添加AVVideoCompositionCoreAnimationTool和CALayer,该文件就会出现。 (CALayer显示正确,但背后的视频位于其侧面,并且文件的宽高比关闭)。我尝试将变换应用于CALayer,并在ACVideoComposition中设置变换。这些都不会改变生成的文件的方向(它仍然是480x369,而不是360x480)。有没有办法用AVVideoCompositionCoreAnimationTool渲染肖像模式视频?
首先,我设置了一个AVMutableComposition和AVMutableVideoComposition
AVMutableComposition *composition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionVideoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVURLAsset *videoAsset = [AVURLAsset URLAssetWithURL:url options:nil];
CMTimeRange timeRange = CMTimeRangeMake(kCMTimeZero, [videoAsset duration]);
AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
CGSize videoSize = CGSizeApplyAffineTransform(clipVideoTrack.naturalSize, clipVideoTrack.preferredTransform);
videoSize.width = fabs(videoSize.width);
videoSize.height = fabs(videoSize.height);
CMTime titleDuration = CMTimeMakeWithSeconds(5, 600);
CMTimeRange titleRange = CMTimeRangeMake(kCMTimeZero, titleDuration);
[compositionVideoTrack insertTimeRange:titleRange ofTrack:nil atTime:kCMTimeZero error:nil];
[compositionVideoTrack insertTimeRange:timeRange ofTrack:clipVideoTrack atTime:titleDuration error:nil];
compositionVideoTrack.preferredTransform = clipVideoTrack.preferredTransform;
AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
AVMutableVideoCompositionInstruction *passThroughInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
passThroughInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, [composition duration]);
AVAssetTrack *videoTrack = [[composition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
passThroughInstruction.layerInstructions = [NSArray arrayWithObject:passThroughLayer];
videoComposition.instructions = [NSArray arrayWithObject:passThroughInstruction];
videoComposition.frameDuration = CMTimeMake(1, 30);
videoComposition.renderSize = videoSize;
videoComposition.renderScale = 1.0;
一个标题为
的CALayerCALayer *animationLayer = [CALayer layer];
animationLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height);
CATextLayer *titleLayer = [CATextLayer layer];
titleLayer.string = [effect valueForKey:@"title"];
titleLayer.font = [effect valueForKey:@"font"];
titleLayer.fontSize = 30;
titleLayer.alignmentMode = kCAAlignmentCenter;
titleLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height / 6);
[animationLayer addSublayer:titleLayer];
titleLayer.anchorPoint = CGPointMake(0.5, 0.5);
titleLayer.position = CGPointMake(CGRectGetMidX(layer.bounds), CGRectGetMidY(layer.bounds));
CABasicAnimation *fadeAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
fadeAnimation.fromValue = [NSNumber numberWithFloat:1.0];
fadeAnimation.toValue = [NSNumber numberWithFloat:0.0];
fadeAnimation.additive = NO;
fadeAnimation.removedOnCompletion = NO;
fadeAnimation.beginTime = 3.5;
fadeAnimation.duration = 1.0;
fadeAnimation.fillMode = kCAFillModeBoth;
[titleLayer addAnimation:fadeAnimation forKey:nil];
最后,我将CALayer添加到AVMutableVideoComposition
CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
parentLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height);
parentLayer.anchorPoint = CGPointMake(0, 0);
parentLayer.position = CGPointMake(0, 0);
videoLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height);
[parentLayer addSublayer:videoLayer];
videoLayer.anchorPoint = CGPointMake(0.5, 0.5);
videoLayer.position = CGPointMake(CGRectGetMidX(parentLayer.bounds), CGRectGetMidY(parentLayer.bounds));
[parentLayer addSublayer:layer];
animationLayer.anchorPoint = CGPointMake(0.5, 0.5);
animationLayer.position = CGPointMake(CGRectGetMidX(parentLayer.bounds), CGRectGetMidY(parentLayer.bounds));
videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
并导出!
AVAssetExportSession *exportSession = [[[AVAssetExportSession alloc] initWithAsset:composition presetName:AVAssetExportPresetMediumQuality] autorelease];
exportSession.videoComposition = videoComposition;
NSURL *segmentFileURL = //some local URL
exportSession.outputFileType = @"com.apple.quicktime-movie";
exportSession.outputURL = segmentFileURL;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
switch ([exportSession status]) {
case AVAssetExportSessionStatusFailed:
Log(@"Export failed: %@", [exportSession error]);
break;
case AVAssetExportSessionStatusCancelled:
Log(@"Export canceled");
break;
case AVAssetExportSessionStatusCompleted:
Log(@"Export done");
break;
}
}];
此代码在横向模式下工作,如果我删除行videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
答案 0 :(得分:3)
尝试此操作并添加其他说明。
///turn video 90 degrees
AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:clipVideoTrack];
CGAffineTransform rotationTransform = CGAffineTransformMakeRotation(degreesToRadians(90.0));
CGAffineTransform rotateTranslate = CGAffineTransformTranslate(rotationTransform,320,0);
[passThroughLayer setTransform:rotateTranslate atTime:kCMTimeZero];
让我知道它是怎么回事!
MacMike