使AVMutableComposition与图像(方面填充)和视频在方面适合

Question

我正试图制作一个新的视频，使用的图像大小始终为：CGSize(375667(，但视频大小不同，contentMode为`aspectFit’。问题是，我不知道如何使整个视频合成具有正确的大小(即图像大小(，相反，它是视频的自然大小，并产生了一堆奇怪的结果。(编辑注意：视频应该像普通aspectFit对UIImageView所做的那样集中在视图中。(

这是一个我正在努力实现的目标的例子。。。请注意，我已经有了图像和视频，我所需要做的就是用它们制作新的视频。这就是它应该是什么样子(在图像中(：

此处的期望结果图像--

这是我目前正在尝试的代码；背景"；(资产中的375667张随机图片。(：我想我可能是在做评论周围的事情；重要的东西；不恰当。。。但我目前还搞不清楚：/

func makeVideo(fromVideoAt videoURL: URL, forName name: String, onComplete: @escaping (URL?) -> Void) {
let asset = AVURLAsset(url: videoURL)
let composition = AVMutableComposition()

guard
let compositionTrack = composition.addMutableTrack(
withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid),
let assetTrack = asset.tracks(withMediaType: .video).first
else {
print("Something is wrong with the asset.")
onComplete(nil)
return
}

do {
let timeRange = CMTimeRange(start: .zero, duration: asset.duration)
try compositionTrack.insertTimeRange(timeRange, of: assetTrack, at: .zero)

if let audioAssetTrack = asset.tracks(withMediaType: .audio).first,
let compositionAudioTrack = composition.addMutableTrack(withMediaType: .audio, preferredTrackID: kCMPersistentTrackID_Invalid) {
try compositionAudioTrack.insertTimeRange(timeRange, of: audioAssetTrack, at: .zero)
}
} catch {
print(error)
onComplete(nil)
return
}

compositionTrack.preferredTransform = assetTrack.preferredTransform
let videoInfo = orientation(from: assetTrack.preferredTransform)



//Important stuff potentially? general below:

let videoSize: CGSize
if videoInfo.isPortrait {
videoSize = CGSize(width: 720, height: 1280)
} else {
videoSize = CGSize(width: 720, height: 1280) //720.0, 1280 tiktok default..?
}



//the Background image:
let backgroundLayer = CALayer()
backgroundLayer.frame = CGRect(origin: .zero, size: videoSize) //videosize

backgroundLayer.contents = UIImage(named: "background")?.cgImage
backgroundLayer.contentsGravity = .resizeAspectFill
backgroundLayer.backgroundColor = UIColor.red.cgColor
//Video layer:
let videoLayer = CALayer()
//    videoLayer.frame = CGRect(origin: .zero, size: CGSize(width: composition.naturalSize.width, height: composition.naturalSize.height)) //videosize
videoLayer.backgroundColor = UIColor.yellow.cgColor

print(composition.naturalSize, "<-- composition.naturalSize")
videoLayer.frame = CGRect(origin: .zero, size: CGSize(width: videoSize.width, height: composition.naturalSize.height))//CGRect(x: 0, y: 0, width: videoSize.width, height: composition.naturalSize.height)

//OutPutlayer putting the together?
let outputLayer = CALayer()
outputLayer.frame = CGRect(origin: .zero, size: CGSize(width: 720, height: 1280)) //videosize
outputLayer.backgroundColor = UIColor.white.cgColor
outputLayer.addSublayer(backgroundLayer)
outputLayer.addSublayer(videoLayer)
//    outputLayer.addSublayer(overlayLayer)

let videoComposition = AVMutableVideoComposition()
videoComposition.renderSize = videoSize
videoComposition.frameDuration = CMTime(value: 1, timescale: 30)
videoComposition.animationTool = AVVideoCompositionCoreAnimationTool(postProcessingAsVideoLayer: videoLayer, in: outputLayer)


//Setting Up Instructions
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRange(start: .zero, duration: composition.duration)
videoComposition.instructions = [instruction]
let layerInstruction = compositionLayerInstruction(for: compositionTrack, assetTrack: assetTrack)
instruction.layerInstructions = [layerInstruction]



//EXPORTING
guard let export = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality) else {
print("Cannot create export session.")
onComplete(nil)
return
}

let videoName = UUID().uuidString
let exportURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(videoName).appendingPathExtension("mp4")

export.videoComposition = videoComposition
export.outputFileType = .mov
export.outputURL = exportURL

export.exportAsynchronously {
DispatchQueue.main.async {
switch export.status {
case .completed:
onComplete(exportURL)
default:
print("Something went wrong during export.")
print(export.error ?? "unknown error")
onComplete(nil)
break
}
}
}
}

Answer 1

尝试使用此代码https://github.com/vabe1337/VBVideoEditor.它渲染的视频像TikTok，Instagram。