我正试图在AVPlayer中播放慢动作视频（由用户的iPhone拍摄）。
我正从检索者的AVAsset检索PHAsset请求：
[manager requestAVAssetForVideo:PHAsset
options:videoRequestOptions
resultHandler:^(AVAsset * avasset, AVAudioMix * audioMix, NSDictionary * info) {}];
问题是一旦播放，我就会收到此错误：
-[AVComposition URL]: unrecognized selector sent to instance 0x138d17f40
但是，如果我在经理请求中设置此选项，它将以120 / 240fps的正常速度视频播放并且不会崩溃：
videoRequestOptions.version = PHVideoRequestOptionsVersionOriginal;
怎么回事？默认version属性为PHVideoRequestOptionsVersionCurrent，其中包含慢动作，用户编辑和修剪等。
我想播放该视频版本。感谢
答案 0 :(得分：6)
事实证明，慢动作视频以AVComposition传递。
您可以将其导出到视频文件/网址中，然后像处理其他任何视频一样处理它。
此处的解决方案：https://overflow.buffer.com/2016/02/29/slow-motion-video-ios/
//Output URL
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = paths.firstObject;
NSString *myPathDocs = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"mergeSlowMoVideo-%d.mov",arc4random() % 1000]];
NSURL *url = [NSURL fileURLWithPath:myPathDocs];
//Begin slow mo video export
AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetHighestQuality];
exporter.outputURL = url;
exporter.outputFileType = AVFileTypeQuickTimeMovie;
exporter.shouldOptimizeForNetworkUse = YES;
[exporter exportAsynchronouslyWithCompletionHandler:^{
dispatch_async(dispatch_get_main_queue(), ^{
if (exporter.status == AVAssetExportSessionStatusCompleted) {
NSURL *URL = exporter.outputURL;
NSData *videoData = [NSData dataWithContentsOfURL:URL];
// Upload
[self uploadSelectedVideo:video data:videoData];
}
});
}];
答案 1 :(得分：0)
对于那些来这里寻找快速答案的人来说，这是我在项目中使用的快速翻译，我需要慢动作视频的网址与AVPlayerViewController一起播放：
else if asset is AVComposition {
//Slow-Motion Assets are passed as AVComposition
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let documentsDirectory: NSString? = paths.first as NSString?
if documentsDirectory != nil {
let random = Int(arc4random() % 1000)
let pathToAppend = String(format: "mergeSlowMoVideo-%d.mov", random)
let myPathDocs = documentsDirectory!.strings(byAppendingPaths: [pathToAppend])
let myPath = myPathDocs.first
if myPath != nil {
let url = URL(fileURLWithPath: myPath!)
let exporter = AVAssetExportSession(asset: asset!, presetName: AVAssetExportPresetHighestQuality)
if exporter != nil {
exporter!.outputURL = url
exporter!.outputFileType = AVFileTypeQuickTimeMovie
exporter!.shouldOptimizeForNetworkUse = true
exporter!.exportAsynchronously(completionHandler: {
AsyncUtil.asyncMain {
let url = exporter!.outputURL
if url != nil {
let player = AVPlayer(url: url!)
let playerViewController = AVPlayerViewController()
playerViewController.player = player
playerViewController.modalTransitionStyle = .crossDissolve
view.present(playerViewController, animated: true) {
playerViewController.player!.play()
}
}
}
})
}
}
答案 2 :(得分：0)
使用自定义视图在以上Swift 4 n中播放Slo-mo和库视频
var vcPlayer = AVPlayerViewController()
var player = AVPlayer()
func playallVideo(_ customView: UIView, asset: PHAsset) {
guard asset.mediaType == .video
else {
print("Not a valid video media type")
return
}
let options = PHVideoRequestOptions()
options.isNetworkAccessAllowed = true
PHCachingImageManager().requestPlayerItem(forVideo: asset, options: options) { (playerItem, info) in
DispatchQueue.main.async {
self.player = AVPlayer(playerItem: playerItem)
self.vcPlayer.player = self.player
self.vcPlayer.view.frame = customView.bounds
self.vcPlayer.videoGravity = .resizeAspectFill
self.vcPlayer.showsPlaybackControls = true
//self.vcPlayer.allowsPictureInPicturePlayback = true
self.playerView.addSubview(self.vcPlayer.view)
self.player.play()
}
}
}
/**********Function Call ********/
self.playallVideo(self.playerView/*YourCustomView*/, asset: currentAssetArr[currentIndex]/*Current PHAsset Fetched from Library*/)
:)享受
答案 3 :(得分：0)
在 Swift 中寻找答案？ 我是这样做的
在 iOS swift 中创建“慢动作”视频并不容易，我遇到了许多“慢动作”，后来发现它们不起作用或其中的某些代码已贬值。所以我终于找到了一种在 Swift 中制作慢动作的方法。 此代码可用于 120fps 也大于此。
这是“我为实现慢动作而创建的代码片段”
如果此代码有效，请给我一个 UPVOTE。
func slowMotion(pathUrl: URL) {
let videoAsset = AVURLAsset.init(url: pathUrl, options: nil)
let currentAsset = AVAsset.init(url: pathUrl)
let vdoTrack = currentAsset.tracks(withMediaType: .video)[0]
let mixComposition = AVMutableComposition()
let compositionVideoTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
let videoInsertError: Error? = nil
var videoInsertResult = false
do {
try compositionVideoTrack?.insertTimeRange(
CMTimeRangeMake(start: .zero, duration: videoAsset.duration),
of: videoAsset.tracks(withMediaType: .video)[0],
at: .zero)
videoInsertResult = true
} catch let videoInsertError {
}
if !videoInsertResult || videoInsertError != nil {
//handle error
return
}
var duration: CMTime = .zero
duration = CMTimeAdd(duration, currentAsset.duration)
//MARK: You see this constant (videoScaleFactor) this helps in achieving the slow motion that you wanted. This increases the time scale of the video that makes slow motion
// just increase the videoScaleFactor value in order to play video in higher frames rates(more slowly)
let videoScaleFactor = 2.0
let videoDuration = videoAsset.duration
compositionVideoTrack?.scaleTimeRange(
CMTimeRangeMake(start: .zero, duration: videoDuration),
toDuration: CMTimeMake(value: videoDuration.value * Int64(videoScaleFactor), timescale: videoDuration.timescale))
compositionVideoTrack?.preferredTransform = vdoTrack.preferredTransform
let dirPaths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).map(\.path)
let docsDir = dirPaths[0]
let outputFilePath = URL(fileURLWithPath: docsDir).appendingPathComponent("slowMotion\(UUID().uuidString).mp4").path
if FileManager.default.fileExists(atPath: outputFilePath) {
do {
try FileManager.default.removeItem(atPath: outputFilePath)
} catch {
}
}
let filePath = URL(fileURLWithPath: outputFilePath)
let assetExport = AVAssetExportSession(
asset: mixComposition,
presetName: AVAssetExportPresetHighestQuality)
assetExport?.outputURL = filePath
assetExport?.outputFileType = .mp4
assetExport?.exportAsynchronously(completionHandler: {
switch assetExport?.status {
case .failed:
print("asset output media url = \(String(describing: assetExport?.outputURL))")
print("Export session faiied with error: \(String(describing: assetExport?.error))")
DispatchQueue.main.async(execute: {
// completion(nil);
})
case .completed:
print("Successful")
let outputURL = assetExport!.outputURL
print("url path = \(String(describing: outputURL))")
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: outputURL!)
}) { saved, error in
if saved {
print("video successfully saved in photos gallery view video in photos gallery")
}
if (error != nil) {
print("error in saing video \(String(describing: error?.localizedDescription))")
}
}
DispatchQueue.main.async(execute: {
// completion(_filePath);
})
case .none:
break
case .unknown:
break
case .waiting:
break
case .exporting:
break
case .cancelled:
break
case .some(_):
break
}
})
}