Question

如果我在Swift中有一个MPMoviePlayerController：

MPMoviePlayerController mp = MPMoviePlayerController(contentURL: url)

我有没有办法让视频中的帧数位于url？如果没有，还有其他方法来确定帧数吗？

Answer 1

我认为MPMoviePlayerController可以帮助你。

使用AVAssetReader并计算它返回给您的CMSampleBuffer的数量。您可以将其配置为甚至不解码帧，有效地解析文件，因此它应该快速且内存有效。

像

这样的东西

    var asset = AVURLAsset(URL: url, options: nil)
    var reader = AVAssetReader(asset: asset, error: nil)
    var videoTrack = asset.tracksWithMediaType(AVMediaTypeVideo)[0] as! AVAssetTrack

    var readerOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: nil) // NB: nil, should give you raw frames
    reader.addOutput(readerOutput)
    reader.startReading()

    var nFrames = 0

    while true {
        var sampleBuffer = readerOutput.copyNextSampleBuffer()
        if sampleBuffer == nil {
            break
        }

        nFrames++
    }

    println("Num frames: \(nFrames)")

很抱歉，如果这不是惯用的话，我也不太了解。

Answer 2

快速5

 func getNumberOfFrames(url: URL) -> Int {
        let asset = AVURLAsset(url: url, options: nil)
        do {
            let reader = try AVAssetReader(asset: asset)
        //AVAssetReader(asset: asset, error: nil)
            let videoTrack = asset.tracks(withMediaType: AVMediaType.video)[0]

            let readerOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: nil) // NB: nil, should give you raw frames
            reader.add(readerOutput)
        reader.startReading()

        var nFrames = 0

        while true {
            let sampleBuffer = readerOutput.copyNextSampleBuffer()
            if sampleBuffer == nil {
                break
            }

            nFrames = nFrames+1
        }

        print("Num frames: \(nFrames)")
            return nFrames
        }catch {
            print("Error: \(error)")
        }
        return 0
    }

Answer 3

您还可以使用每秒帧数来计算总帧数。

var player: AVPlayer?
var playerController = AVPlayerViewController()
var videoFPS: Int = 0
var totalFrames: Int?


guard let videoURL = "" else { return }
player = AVPlayer(url: videoURL)
playerController.player = player
guard player?.currentItem?.asset != nil else {
    return
}
let asset = self.player?.currentItem?.asset
let tracks = asset!.tracks(withMediaType: .video)
let fps = tracks.first?.nominalFrameRate
let duration = self.player?.currentItem?.duration

self.videoFPS = lround(Double(fps!))
self.totalFrames = lround(Double(self!.videoFPS) * durationSeconds)

iOS确定视频中的帧数

3 个答案: