我正在使用AVFoundation Framework构建iOS应用程序，Objective-C和Xcode 7.1。我正在做的是获取录制的视频，添加文本图层并导出。我的问题是，当我在肖像上录制时，导出的视频在风景中！我已经挣扎了几个小时，无法解决它。我发现了类似的问题，但没有一个答案对我有帮助。 这是我的代码：
AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:self.videoURL options:nil];
AVMutableComposition* mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack* compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
CMTime insertTime = kCMTimeZero;
insertTime = CMTimeAdd(insertTime, compositionVideoTrack.timeRange.duration);
AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
// [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
// ofTrack:clipVideoTrack
// atTime:kCMTimeZero error:nil];
AVAssetTrack* audioAssetTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, clipVideoTrack.timeRange.duration) ofTrack:clipVideoTrack atTime:insertTime error:nil];
[compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioAssetTrack.timeRange.duration) ofTrack:audioAssetTrack atTime:insertTime error:nil];
[compositionVideoTrack setPreferredTransform:[[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] preferredTransform]];
CGSize videoSize = [clipVideoTrack naturalSize];
CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
CATextLayer *subtitle1Text = [[CATextLayer alloc] init];
[subtitle1Text setFont:@"Helvetica"];
[subtitle1Text setFontSize:32];
[subtitle1Text setFrame:CGRectMake(0, 0, videoSize.width, 100)];
[subtitle1Text setString:self.titleField.text];
[subtitle1Text setAlignmentMode:kCAAlignmentCenter];
[subtitle1Text setForegroundColor:[[UIColor blackColor] CGColor]];
subtitle1Text.backgroundColor = [UIColor whiteColor].CGColor;
CALayer *overlayLayer = [CALayer layer];
[overlayLayer addSublayer:subtitle1Text];
overlayLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
[overlayLayer setMasksToBounds:YES];
parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:overlayLayer];
float startTime = 0.5f;
float duration = 4.0f;
overlayLayer.opacity = 0.0;
CABasicAnimation *myAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
[myAnimation setBeginTime: startTime];
[myAnimation setDuration: duration];
[myAnimation setFromValue:[NSNumber numberWithFloat:0.5]];
[myAnimation setToValue:[NSNumber numberWithFloat:1.0]];
[myAnimation setRemovedOnCompletion:NO];
[overlayLayer addAnimation:myAnimation forKey:@"myUniqueAnimationKey"];
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];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* videoFileName = [NSString stringWithFormat:@"textOverlayVideo-%@.mov",[NSDate date]];
NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent:videoFileName];
fileURL = [NSURL fileURLWithPath:myPathDocs];
AVAssetExportSession* exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
exporter.outputURL = fileURL;
exporter.videoComposition = videoComp;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
switch (exporter.status)
{
case AVAssetExportSessionStatusFailed:
NSLog(@"AVAssetExportSessionStatusFailed");
break;
case AVAssetExportSessionStatusCompleted:
NSLog(@"AVAssetExportSessionStatusCompleted");
//[self syncFile];
imageData = [NSData dataWithContentsOfURL:fileURL];
[self send];
break;
case AVAssetExportSessionStatusWaiting:
NSLog(@"AVAssetExportSessionStatusWaiting");
break;
default:
break;
}
});
}];}
谢谢大家。
答案 0 :(得分：0)
尝试设置
compositionVideoTrack.preferredTransform = clipVideoTrack.preferredTransform;
答案 1 :(得分：0)
这是解决方案
-(void)addTextOverlayToVideo
{
// 2 - Create AVMutableComposition object. This object will hold your AVMutableCompositionTrack instances.
AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];
// 3 - Video track
AVMutableCompositionTrack *videoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
preferredTrackID:kCMPersistentTrackID_Invalid];
[videoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset.duration)
ofTrack:[[avAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]
atTime:kCMTimeZero error:nil];
// 3.1 - Create AVMutableVideoCompositionInstruction
AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, avAsset.duration);
// 3.2 - Create an AVMutableVideoCompositionLayerInstruction for the video track and fix the orientation.
AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
AVAssetTrack *videoAssetTrack = [[avAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
UIImageOrientation videoAssetOrientation_ = UIImageOrientationUp;
BOOL isVideoAssetPortrait_ = NO;
CGAffineTransform videoTransform = videoAssetTrack.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;
}
[videolayerInstruction setTransform:videoAssetTrack.preferredTransform atTime:kCMTimeZero];
[videolayerInstruction setOpacity:0.0 atTime:avAsset.duration];
// 3.3 - Add instructions
mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];
AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];
CGSize naturalSize;
if(isVideoAssetPortrait_){
naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
} else {
naturalSize = videoAssetTrack.naturalSize;
}
float renderWidth, renderHeight;
renderWidth = naturalSize.width;
renderHeight = naturalSize.height;
mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);
mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
CGSize videoSize = naturalSize;
CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
CATextLayer *subtitle1Text = [[CATextLayer alloc] init];
[subtitle1Text setFont:@"Helvetica"];
[subtitle1Text setFontSize:22];
[subtitle1Text setFrame:CGRectMake(0, 0, videoSize.width, 100)];
[subtitle1Text setString:self.titleField.text];
[subtitle1Text setAlignmentMode:kCAAlignmentCenter];
[subtitle1Text setForegroundColor:[[UIColor blackColor] CGColor]];
subtitle1Text.backgroundColor = [UIColor whiteColor].CGColor;
CALayer *overlayLayer = [CALayer layer];
[overlayLayer addSublayer:subtitle1Text];
overlayLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
[overlayLayer setMasksToBounds:YES];
parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height);
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:overlayLayer];
float startTime = 0.5f;
float duration = 4.0f;
overlayLayer.opacity = 0.0;
CABasicAnimation *myAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
[myAnimation setBeginTime: startTime];
[myAnimation setDuration: duration];
[myAnimation setFromValue:[NSNumber numberWithFloat:0.5]];
[myAnimation setToValue:[NSNumber numberWithFloat:1.0]];
[myAnimation setRemovedOnCompletion:NO];
[overlayLayer addAnimation:myAnimation forKey:@"myUniqueAnimationKey"];
mainCompositionInst.renderSize = videoSize;
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
mainCompositionInst.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
//[self applyVideoEffectsToComposition:mainCompositionInst size:naturalSize];
// 4 - Get path
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent:
[NSString stringWithFormat:@"FinalVideo-%d.mov",arc4random() % 1000]];
NSURL *url = [NSURL fileURLWithPath:myPathDocs];
// 5 - Create exporter
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition
presetName:AVAssetExportPresetHighestQuality];
exporter.outputURL=url;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
exporter.videoComposition = mainCompositionInst;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
switch (exporter.status)
{
case AVAssetExportSessionStatusFailed:
NSLog(@"AVAssetExportSessionStatusFailed");
break;
case AVAssetExportSessionStatusCompleted:
NSLog(@"AVAssetExportSessionStatusCompleted");
//[self syncFile];
imageData = [NSData dataWithContentsOfURL:url];
[self send];
break;
case AVAssetExportSessionStatusWaiting:
NSLog(@"AVAssetExportSessionStatusWaiting");
break;
default:
break;
}
});
}];
}