我正在开发一个应用程序，人们可以在视频上叠加水印，到目前为止我已经能够成功完成。但是，在我第一次使用自定义覆盖保存视频后，如果我再次尝试保存视频，则会因所述错误而失败：
可选（错误域= AVFoundationErrorDomain代码= -11841“操作已停止”UserInfo = {NSLocalizedDescription =操作已停止，NSLocalizedFailureReason =视频无法合成。}）
以下是我保存视频的代码：
@IBAction func saveVideo(sender: AnyObject) {
self.videoAsset = AVAsset(URL: fileURL as NSURL!)
// Create Video track (Video + Audio)
let videoTrack: AVMutableCompositionTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
let audioTrack:AVMutableCompositionTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
do {
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration), ofTrack: self.videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0] , atTime: kCMTimeZero)
try audioTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration), ofTrack: self.videoAsset.tracksWithMediaType(AVMediaTypeAudio)[0] , atTime: kCMTimeZero)
print("Inserted time ranges just fine\n")
} catch let error as NSError {
print("Failed to insert video/audio tracks!!!!\n")
print(error.localizedDescription)
}
videoLayerIntruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack)
let videoAssetTrack: AVAssetTrack = self.videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0]
var videoAssetOrientation_: UIImageOrientation = .Up
var isVideoAssetPortrait_: Bool = false
let videoTransform:CGAffineTransform = videoAssetTrack.preferredTransform
if videoTransform.a == 0 && videoTransform.b == 1.0 && videoTransform.c == -1.0 && videoTransform.d == 0 {
videoAssetOrientation_ = .Right
isVideoAssetPortrait_ = true
}
if videoTransform.a == 0 && videoTransform.b == -1.0 && videoTransform.c == 1.0 && videoTransform.d == 0 {
videoAssetOrientation_ = .Left
isVideoAssetPortrait_ = true
}
if videoTransform.a == 1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == 1.0 {
videoAssetOrientation_ = .Up
}
if videoTransform.a == -1.0 && videoTransform.b == 0 && videoTransform.c == 0 && videoTransform.d == -1.0 {
videoAssetOrientation_ = .Down
}
videoLayerIntruction.setTransform(videoAssetTrack.preferredTransform, atTime: kCMTimeZero)
mainInstruction.layerInstructions = [videoLayerIntruction]
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration)
var naturalSize = CGSize()
if isVideoAssetPortrait_ {
naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width)
} else {
naturalSize = videoAssetTrack.naturalSize
}
renderWidth = naturalSize.width
renderHeight = naturalSize.height
parentLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight)
parentLayer.geometryFlipped = true
parentLayer.anchorPoint = CGPointMake(0.5, 0.5)
videoLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight)
self.overlayLayer.frame = CGRectMake(self.renderWidth, self.renderHeight, self.newRatioWidth, self.newRatioHeight)
self.overlayLayer.addAnimation(self.animation, forKey: "contents")
self.overlayLayer.anchorPoint = CGPointMake(0.5, 0.5)
self.overlayLayer.contentsGravity = kCAGravityResizeAspect
parentLayer.addSublayer(videoLayer)
if addedOverlay == true {
parentLayer.addSublayer(overlayLayer)
}
mainCompositionInst.renderScale = 1.0
mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight)
mainCompositionInst.instructions = [mainInstruction]
mainCompositionInst.frameDuration = CMTimeMake(1, 30)
mainCompositionInst.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, inLayer: parentLayer)
outputURL = NSURL(fileURLWithPath: NSTemporaryDirectory()).URLByAppendingPathComponent("CreatedVideo-\(NSUUID().UUIDString).mov")
let exporter: AVAssetExportSession = AVAssetExportSession(asset: videoAsset, presetName: AVAssetExportPresetHighestQuality)!
exporter.outputURL = outputURL
exporter.outputFileType = AVFileTypeQuickTimeMovie
exporter.shouldOptimizeForNetworkUse = false
exporter.videoComposition = mainCompositionInst
exporter.exportAsynchronouslyWithCompletionHandler({
dispatch_async(dispatch_get_main_queue(), {
self.exportVideo(exporter)
switch exporter.status{
case AVAssetExportSessionStatus.Failed:
print("FAILED EXPORT - \(exporter.error)\n")
case AVAssetExportSessionStatus.Cancelled:
print("canceled \(exporter.error)\n")
default:
print("COMPLETED EXPORT\n")
}
})
})
}
func exportVideo(sender: AVAssetExportSession) {
print("Asked to export\n")
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(sender.outputURL!)
}, completionHandler: { success, error in
if success {
print("Success! Finished saving video.")
} else {
print("ERROR - " + (error?.localizedDescription)!)
}
})
}
有没有人知道在第一次成功工作后组合物开始失败的原因是什么？会喜欢任何建议！