swift – 通过AVFoundation获取视频中的帧数

发布时间：2020-12-14 05:40:59 所属栏目：百科来源：网络整理

导读：我试图在我刚刚打开的视频中找到帧数,而不解码所有帧. 我用AVAsset打开然后为视频获取AVAssetTrack.接下来是什么？一种相对昂贵的方法是使用AVAssetReader读取所有帧并随时计算它们. let asset = AVAsset(url: url)let assetTrack = asset.tracksWithMedia

我试图在我刚刚打开的视频中找到帧数,而不解码所有帧.

我用AVAsset打开然后为视频获取AVAssetTrack.接下来是什么？

一种相对昂贵的方法是使用AVAssetReader读取所有帧并随时计算它们.

let asset = AVAsset(url: url)
let assetTrack = asset.tracksWithMediaType(AVMediaTypeVideo).first!
let assetReader = try! AVAssetReader(asset: self)
let assetReaderOutputSettings = [
    kCVPixelBufferPixelFormatTypeKey as String: NSNumber(unsignedInt: kCVPixelFormatType_32BGRA)
]
let assetReaderOutput = AVAssetReaderTrackOutput(track: assetTrack,outputSettings: assetReaderOutputSettings)
assetReaderOutput.alwaysCopiesSampleData = false
assetReader.addOutput(assetReaderOutput)
assetReader.startReading()

var frameCount = 0
var sample: CMSampleBufferRef? = assetReaderOutput.copyNextSampleBuffer()

while (sample != nil) {
    frameCount++
    sample = assetReaderOutput.copyNextSampleBuffer()
}

// now you have frame count
print(frameCount)

（编辑：李大同）

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