编辑:最奇怪的事情:它似乎是从完整的应用程序运行此代码时,一切正常,但我总是运行从我的电影创作单元测试,只有它没有工作。试图找出为什么...从单元测试运行时,CATextLayer没有出现在AVMutableComposition中
我想结合视频+音频+文本使用AVMutableComposition并将其导出到一个新的视频。
我的代码是基于AVEditDemo从WWDC '10
我添加了一个紫色的背景,CATextLayer这样我就可以知道它是出口到电影中的事实,但没有文字显示...我尝试玩各种字体,位置,颜色定义,但没有什么帮助,所以我决定在这里发布代码,看看是否有人偶然发现了类似的东西,并能告诉我我错过了什么。
下面的代码(self.audio和self.video是AVURLAssets):需要
CMTime exportDuration = self.audio.duration;
AVMutableComposition *composition = [[AVMutableComposition alloc] init];
AVMutableCompositionTrack *compositionVideoTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *videoTrack = [[self.video tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
// add the video in loop until the audio ends
CMTime currStartTime = kCMTimeZero;
while (CMTimeCompare(currStartTime, exportDuration) < 0) {
CMTime timeRemaining = CMTimeSubtract(exportDuration, currStartTime);
CMTime currLoopDuration = self.video.duration;
if (CMTimeCompare(currLoopDuration, timeRemaining) > 0) {
currLoopDuration = timeRemaining;
}
CMTimeRange currLoopTimeRange = CMTimeRangeMake(kCMTimeZero, currLoopDuration);
[compositionVideoTrack insertTimeRange:currLoopTimeRange ofTrack:videoTrack
atTime:currStartTime error:nil];
currStartTime = CMTimeAdd(currStartTime, currLoopDuration);
}
AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *audioTrack = [self.audio.tracks objectAtIndex:0];
[compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, self.audio.duration) ofTrack:audioTrack atTime:kCMTimeZero error:nil];
AVMutableVideoComposition *videoComposition;
// the text layer part - THIS IS THE PART THAT DOESN'T WORK WELL
CALayer *animatedTitleLayer = [CALayer layer];
CATextLayer *titleLayer = [[CATextLayer alloc] init];
titleLayer.string = @"asdfasdf";
titleLayer.alignmentMode = kCAAlignmentCenter;
titleLayer.bounds = CGRectMake(0, 0, self.video.naturalSize.width/2, self.video.naturalSize.height/2);
titleLayer.opacity = 1.0;
titleLayer.backgroundColor = [UIColor purpleColor].CGColor;
[animatedTitleLayer addSublayer:titleLayer];
animatedTitleLayer.position = CGPointMake(self.video.naturalSize.width/2.0, self.video.naturalSize.height/2.0);
// build a Core Animation tree that contains both the animated title and the video.
CALayer *parentLayer = [CALayer layer];
CALayer *videoLayer = [CALayer layer];
parentLayer.frame = CGRectMake(0, 0, self.video.naturalSize.width, self.video.naturalSize.height);
videoLayer.frame = CGRectMake(0, 0, self.video.naturalSize.width, self.video.naturalSize.height);
[parentLayer addSublayer:videoLayer];
[parentLayer addSublayer:animatedTitleLayer];
videoComposition = [AVMutableVideoComposition videoComposition];
videoComposition.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];
AVMutableVideoCompositionInstruction *passThroughInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
passThroughInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, exportDuration);
AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:compositionVideoTrack];
passThroughInstruction.layerInstructions = [NSArray arrayWithObject:passThroughLayer];
videoComposition.instructions = [NSArray arrayWithObject:passThroughInstruction];
videoComposition.frameDuration = CMTimeMake(1, 30);
videoComposition.renderSize = self.video.naturalSize;
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:composition presetName:AVAssetExportPresetMediumQuality];
exportSession.videoComposition = videoComposition;
exportSession.outputURL = [NSURL fileURLWithPath:self.outputFilePath];
exportSession.outputFileType = AVFileTypeQuickTimeMovie;
[exportSession exportAsynchronouslyWithCompletionHandler:^() {
// save the video ...
}];
我不确定..可能是这可以帮助..http://stackoverflow.com/questions/7205820/iphone-watermark-on-recorded-video – 2012-04-28 15:30:25
谢谢,我做的事情几乎相同那里提到了什么。如果有人发现我的代码和相关答案中的代码之间的重要区别,我会非常感激。 – yonix 2012-04-29 08:19:33
您是否尝试设置字体大小? – 2012-04-30 00:55:56