iOS确定视频中的帧数 [英] iOS Determine Number of Frames in Video

问题描述

如果我在Swift中有一个MPMoviePlayerController：

If I have a MPMoviePlayerController in Swift:

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，是否有其他方法来确定帧数？

Is there a way I can get the number of frames within the video located at url? If not, is there some other way to determine the frame count?

推荐答案

我不认为 MPMoviePlayerController 可以帮助你。

使用 AVAssetReader 并计算<$的数量c $ c> CMSampleBuffer 它返回给你。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。

Use an AVAssetReader and count the number of CMSampleBuffers it returns to you. You can configure it to not even decode the frames, effectively parsing the file, so it should be fast and memory efficient.

类似

    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，如果这不是惯用语，我不知道swift。

Sorry if that's not idiomatic, I don't know swift.

这篇关于iOS确定视频中的帧数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！