我正在尝试创建一个将多个视频合并为一个1920x1080大小的长视频的应用程序。现在的问题是，每当我尝试运行以下代码时，都会出现以下错误。
Optional（Error Domain = AVFoundationErrorDomain代码= -11841“操作 已停止” UserInfo = {NSLocalizedFailureReason =无法播放视频 composition。，NSLocalizedDescription =操作已停止， NSUnderlyingError = 0x283ae3b10 {Error Domain = NSOSStatusErrorDomain Code = -17390“（null）”}}）
func merge( videoArray: [AVAsset] ){
// 1 - Create AVMutableComposition object. This object will hold your AVMutableCompositionTrack instances.
let mixComposition = AVMutableComposition()
var instructions: [AVVideoCompositionInstruction] = []
var totalDuration = CMTime.zero
var currentTime = CMTime.zero
var highestFramerate: __int32_t = 0
var i = 1;
let videoTacks = mixComposition.addMutableTrack(withMediaType: AVMediaType.video,preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
let audioTracks = mixComposition.addMutableTrack(withMediaType: AVMediaType.audio, preferredTrackID: 0)
for video: AVAsset in videoArray {
print("Merging Video - \(i) ")
let videoAseetTrack: AVAssetTrack = video.tracks(withMediaType: AVMediaType.video)[0]
let currentFramerate: __int32_t = __int32_t(roundf(videoAseetTrack.nominalFrameRate))
if(currentFramerate > highestFramerate){
highestFramerate = currentFramerate
}
do {
try videoTacks?.insertTimeRange(CMTimeRange(start: CMTime.zero, duration: video.duration),
of: videoAseetTrack,
at: currentTime)
} catch {
print("Failed to load first track")
}
let audioResult = video.tracks(withMediaType: AVMediaType.audio).indices.contains(0)
if(audioResult == true){
do {
try audioTracks?.insertTimeRange(CMTimeRange(start: CMTime.zero, end: video.duration),
of: video.tracks(withMediaType: AVMediaType.audio)[0] ,
at: currentTime)
} catch {
print("Failed to load Audio track")
}
}
let videoCompositionInstruction = AVMutableVideoCompositionInstruction()
videoCompositionInstruction.timeRange = CMTimeRange(start: currentTime, duration: video.duration)
let layerInstruction = AVMutableVideoCompositionLayerInstruction.init(assetTrack: videoAseetTrack)
////////////////////
let transform = videoAseetTrack.preferredTransform
let assetInfo = orientationFromTransform(transform)
if assetInfo.isPortrait {
let s = 1080 / videoAseetTrack.naturalSize.width
let scaledWidth = videoAseetTrack.naturalSize.height * s
let x = (1920 / 2) - (scaledWidth / 2)
let transform: CGAffineTransform = videoAseetTrack.preferredTransform
let new: CGAffineTransform = transform.concatenating(CGAffineTransform(scaleX: s, y: s))
let degrees : Double = 90; //the value in degrees
let rotate: CGAffineTransform = new.concatenating(CGAffineTransform(rotationAngle: CGFloat(degrees * .pi/180) ))
let newer: CGAffineTransform = new.concatenating(CGAffineTransform(translationX: x, y: 0))
layerInstruction.setTransform(newer, at: CMTime.zero)
}else {
let s = 1920 / videoAseetTrack.naturalSize.width
let transform: CGAffineTransform = videoAseetTrack.preferredTransform
let new: CGAffineTransform = transform.concatenating(CGAffineTransform(scaleX: s, y: s))
let newer: CGAffineTransform = new.concatenating(CGAffineTransform(translationX: 0, y: 0))
layerInstruction.setTransform(newer, at: CMTime.zero)
}
layerInstruction.setTransform(transform, at: CMTime.zero)
///////////////////
videoCompositionInstruction.layerInstructions.append(layerInstruction)
instructions.append(videoCompositionInstruction)
totalDuration = CMTimeAdd(totalDuration, video.duration)
currentTime = CMTimeAdd(currentTime, video.duration)
i = i + 1
}
// 2.3
let mainComposition = AVMutableVideoComposition()
mainComposition.instructions = instructions
mainComposition.frameDuration = CMTime(value: 1, timescale: highestFramerate)
mainComposition.renderSize = CGSize(width: 1920, height: 1080)
// 4 - Get path
guard let documentDirectory = FileManager.default.urls(for: .documentDirectory,
in: .userDomainMask).first else {
return
}
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .short
let date = dateFormatter.string(from: Date())
let randomInt = Int.random(in: 0..<6)
let url = documentDirectory.appendingPathComponent("mergeVideo-\(date)-\(randomInt).mov")
// 5 - Create Exporter
guard let exporter = AVAssetExportSession(asset: mixComposition,
presetName: AVAssetExportPreset1920x1080) else {
return
}
exporter.outputURL = url
exporter.outputFileType = AVFileType.mov
exporter.shouldOptimizeForNetworkUse = true
exporter.videoComposition = mainComposition
// 6 - Perform the Export
exporter.exportAsynchronously() {
if(exporter.status == AVAssetExportSession.Status.completed){
DispatchQueue.main.async {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: url)
}) { saved, error in
if saved {
let alertController = UIAlertController(title: "Your video was successfully saved", message: nil, preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .default, handler: nil)
alertController.addAction(defaultAction)
self.present(alertController, animated: true, completion: nil)
}
}
//self.exportDidFinish(exporter)
}
}else {
print(exporter.status.rawValue)
print(exporter.error)
}
}
}
我认为问题可能与视频计时有关，但我认为我设置正确。如果有人能发现这个问题，那将是一个很大的问题，因为这确实使我受阻。
谢谢
更新
经过更多研究后，问题似乎出在合并已经使用上述代码合并的视频。如果我运行2个新视频，则可以将它们合并并导出。如果然后我使用已导出的视频创建新视频，则会引发错误。有谁知道为什么已经导出的视频可以这样做？