[英]Exporting time lapse with AVAssetExportSession results in black video
[英]Exporting Video in full screen with AVAssetExportSession
我正在嘗試為視頻做一些動畫(錄制后),然后將其導出。 但在任何動畫之前,我有問題的方向,成為風景(沒有導出它是肖像),它解決不了,但現在我有問題,使它全屏。在iphone 6,7加上它的全屏如何在ipad它不是。
這是我的方法:
func export(_ url : URL) {
let composition = AVMutableComposition()
let asset = AVURLAsset(url: url, options: nil)
let track = asset.tracks(withMediaType : AVMediaTypeVideo)
let videoTrack:AVAssetTrack = track[0] as AVAssetTrack
let timerange = CMTimeRangeMake(kCMTimeZero, asset.duration)
let compositionVideoTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
do {
try compositionVideoTrack.insertTimeRange(timerange, of: videoTrack, at: kCMTimeZero)
} catch {
print(error)
}
let compositionAudioTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
for audioTrack in asset.tracks(withMediaType: AVMediaTypeAudio) {
do {
try compositionAudioTrack.insertTimeRange(audioTrack.timeRange, of: audioTrack, at: kCMTimeZero)
} catch {
print(error)
}
}
let size = self.view.bounds.size
let videolayer = CALayer()
videolayer.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
let parentlayer = CALayer()
parentlayer.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
parentlayer.addSublayer(videolayer)
let layercomposition = AVMutableVideoComposition()
layercomposition.frameDuration = CMTimeMake(1, 30)
layercomposition.renderSize = self.view.bounds.size
layercomposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videolayer, in: parentlayer)
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, asset.duration)
let videotrack = composition.tracks(withMediaType: AVMediaTypeVideo)[0] as AVAssetTrack
let layerinstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videotrack)
let ratio = size.height / videoTrack.naturalSize.width
composition.naturalSize = videoTrack.naturalSize
layerinstruction.setTransform(videoTrack.preferredTransform.scaledBy(x: 0.645 , y: ratio).translatedBy(x: self.view.bounds.height, y: 0), at: kCMTimeZero)
instruction.layerInstructions = [layerinstruction]
layercomposition.instructions = [instruction]
let filePath = self.fileName()
let movieUrl = URL(fileURLWithPath: filePath)
guard let assetExport = AVAssetExportSession(asset: composition, presetName:AVAssetExportPresetHighestQuality) else {return}
assetExport.videoComposition = layercomposition
assetExport.outputFileType = AVFileTypeMPEG4
assetExport.outputURL = movieUrl
assetExport.exportAsynchronously(completionHandler: {
switch assetExport.status {
case .completed:
print("success")
let player = AVPlayer(url: movieUrl)
let playerViewController = AVPlayerViewController()
playerViewController.player = player
self.present(playerViewController, animated: true) {
playerViewController.player!.play()
}
break
case .cancelled:
print("cancelled")
break
case .exporting:
print("exporting")
break
case .failed:
print("failed: \(String(describing: assetExport.error))")
break
case .unknown:
print("unknown")
break
case .waiting:
print("waiting")
break
}
})
}
解決我的問題的是改變比例因子和翻譯量。 這是下面的代碼:
let size = self.view.bounds.size
let trackTransform = videoTrack.preferredTransform
let xScale = size.height / videoTrack.naturalSize.width
let yScale = size.width / videoTrack.naturalSize.height
let exportTransform = videoTrack.preferredTransform.translatedBy(x: trackTransform.ty * -1 , y: 0).scaledBy(x: xScale , y: yScale)
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