问题描述
我正试图简单地提高合并视频的导出速度。
这里是代码：//从网上和SO的广泛研究中，我可以大致了解到预设的PassThrough使其变得非常快，但是正如我在代码注释中所写的那样，合并的代码没有似乎可以使用该预设进行导出：/
static func videoCompositionInstruction(_ track: AVCompositionTrack,asset: AVAsset)
-> AVMutableVideoCompositionLayerInstruction {
let instruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
let assetTrack = asset.tracks(withMediaType: .video)[0]
let transform = assetTrack.preferredTransform
let assetInfo = orientationFromTransform(transform)
var scaleToFitRatio = 1080 / assetTrack.naturalSize.width
if assetInfo.isPortrait {
scaleToFitRatio = 1080 / assetTrack.naturalSize.height
let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio,y: scaleToFitRatio)
var finalTransform = assetTrack.preferredTransform.concatenating(scaleFactor)
//was needed in my case (if video not taking entire screen and leaving some parts black - don't know when actually needed so you'll have to try and see when it's needed)
if assetInfo.orientation == .rightMirrored || assetInfo.orientation == .leftMirrored {
finalTransform = finalTransform.translatedBy(x: -transform.ty,y: 0)
}
instruction.setTransform(finalTransform,at: CMTime.zero)
} else {
let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio,y: scaleToFitRatio)
var concat = assetTrack.preferredTransform.concatenating(scaleFactor)
.concatenating(CGAffineTransform(translationX: 0,y: UIScreen.main.bounds.width / 2))
if assetInfo.orientation == .down {
let fixUpsideDown = CGAffineTransform(rotationAngle: CGFloat(Double.pi))
let windowBounds = UIScreen.main.bounds
let yFix = assetTrack.naturalSize.height + windowBounds.height
let centerFix = CGAffineTransform(translationX: assetTrack.naturalSize.width,y: yFix)
concat = fixUpsideDown.concatenating(centerFix).concatenating(scaleFactor)
}
instruction.setTransform(concat,at: CMTime.zero)
}
return instruction
}
static func orientationFromTransform(_ transform: CGAffineTransform)
-> (orientation: UIImage.Orientation,isPortrait: Bool) {
var assetOrientation = UIImage.Orientation.up
var isPortrait = false
if transform.a == 0 && transform.b == 1.0 && transform.c == -1.0 && transform.d == 0 {
assetOrientation = .right
isPortrait = true
} else if transform.a == 0 && transform.b == 1.0 && transform.c == 1.0 && transform.d == 0 {
assetOrientation = .rightMirrored
isPortrait = true
} else if transform.a == 0 && transform.b == -1.0 && transform.c == 1.0 && transform.d == 0 {
assetOrientation = .left
isPortrait = true
} else if transform.a == 0 && transform.b == -1.0 && transform.c == -1.0 && transform.d == 0 {
assetOrientation = .leftMirrored
isPortrait = true
} else if transform.a == 1.0 && transform.b == 0 && transform.c == 0 && transform.d == 1.0 {
assetOrientation = .up
} else if transform.a == -1.0 && transform.b == 0 && transform.c == 0 && transform.d == -1.0 {
assetOrientation = .down
}
return (assetOrientation,isPortrait)
}
func mergeVideosTestSQ(arrayVideos:[AVAsset],completion:@escaping (URL?,Error?) -> ()) {
let mixComposition = AVMutableComposition()
var instructions: [AVMutableVideoCompositionLayerInstruction] = []
var insertTime = CMTime(seconds: 0,preferredTimescale: 1)
/// for each URL add the video and audio tracks and their duration to the composition
for sourceAsset in arrayVideos {
let frameRange = CMTimeRange(start: CMTime(seconds: 0,preferredTimescale: 1),duration: sourceAsset.duration)
guard
let nthVideoTrack = mixComposition.addMutableTrack(withMediaType: .video,preferredTrackID: Int32(kCMPersistentTrackID_Invalid)),let nthAudioTrack = mixComposition.addMutableTrack(withMediaType: .audio,//0 used to be kCMPersistentTrackID_Invalid
let assetVideoTrack = sourceAsset.tracks(withMediaType: .video).first
else {
print("didnt work")
return
}
var assetAudioTrack: AVAssetTrack?
assetAudioTrack = sourceAsset.tracks(withMediaType: .audio).first
print(assetAudioTrack,",-- assetAudioTrack???",assetAudioTrack?.asset,"<-- hes",sourceAsset)
do {
try nthVideoTrack.insertTimeRange(frameRange,of: assetVideoTrack,at: insertTime)
try nthAudioTrack.insertTimeRange(frameRange,of: assetAudioTrack!,at: insertTime)
//instructions:
let nthInstruction = MainCamVC.videoCompositionInstruction(nthVideoTrack,asset: sourceAsset)
nthInstruction.setOpacity(0.0,at: CMTimeAdd(insertTime,sourceAsset.duration)) //sourceasset.duration
instructions.append(nthInstruction)
insertTime = insertTime + sourceAsset.duration //sourceAsset.duration
} catch {
DispatchQueue.main.async {
print("didnt wor2k")
}
}
}
let mainInstruction = AVMutableVideoCompositionInstruction()
mainInstruction.timeRange = CMTimeRange(start: CMTime(seconds: 0,duration: insertTime)
mainInstruction.layerInstructions = instructions
let mainComposition = AVMutableVideoComposition()
mainComposition.instructions = [mainInstruction]
mainComposition.frameDuration = CMTimeMake(value: 1,timescale: 30)
mainComposition.renderSize = CGSize(width: 1080,height: 1920)
let outputFileURL = URL(fileURLWithPath: NSTemporaryDirectory() + "merge.mp4")
//below to clear the video form docuent folder for new vid...
let fileManager = FileManager()
try? fileManager.removeItem(at: outputFileURL)
/// try to start an export session and set the path and file type
if let exportSession = AVAssetExportSession(asset: mixComposition,presetName: AVAssetExportPresetHighestQuality) { //DOES NOT WORK WITH AVAssetExportPresetPassthrough
exportSession.outputFileType = .mov
exportSession.outputURL = outputFileURL
exportSession.videoComposition = mainComposition
exportSession.shouldOptimizeForNetworkUse = true
/// try to export the file and handle the status cases
exportSession.exportAsynchronously {
if let url = exportSession.outputURL{
completion(url,nil)
}
if let error = exportSession.error {
completion(nil,error)
}
}
}
}
请注意，我有说明以保持正确的方向。
感谢您的帮助！我只需要更快，它大约需要videoDuration / 2秒才能及时导出...
解决方法
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