Question

我需要获得音频项目（远程）比特率 - 320,128等。找到答案 - How to get an MP3 bit rate in SWIFT，但它无法正常工作。我可以得到一个大小的项目，但我的比特率看起来很奇怪 - 像154,540.34等。请帮忙！

Answer 1

我找到了解决方案： 1.对于本地文件：

func getSongBitrate(audioURL: URL, duration: Int, completition: @escaping (Int) -> ()) {
    do {
        let attr = try FileManager.default.attributesOfItem(atPath: audioURL.path)

        if var fileSize = attr[FileAttributeKey.size] as?  UInt64 {
            let dict = attr as NSDictionary
            fileSize = dict.fileSize()

            let kbit = fileSize/128//calculate bytes to kbit
            let kbps = ceil(round(Double(kbit)/Double(duration))/16)*16
            completition(Int(kbps))
        }
    } catch {
        print("Error: \(error)")
        completition(Int(0))
    }
}

对于URL远程文件：

func getBitrate(audioURL: URL, duration: Int, completition: @escaping (Int) -> ()) {

    DispatchQueue.global().async {
        let request1: NSMutableURLRequest = NSMutableURLRequest(url: audioURL)
        request1.httpMethod = "HEAD"

        var response : URLResponse?
        print("GO TO RESPONSE")
        do {
            try NSURLConnection.sendSynchronousRequest(request1 as URLRequest, returning: &response)

            if let httpResponse = response as? HTTPURLResponse {

                let size = httpResponse.expectedContentLength
                let kbit = size/128;//calculate bytes to kbit
                let kbps = ceil(round(Double(kbit)/Double(duration))/16)*16

                 // print("kbps === \(kbps)")

                if self.songQuality == 0 {
                   self.songQuality = Int(kbps)
               }

                ////

                DispatchQueue.main.async {
                    completition(Int(kbps))
                }

                ////

            }

        } catch (let e) {
            print(e)
            DispatchQueue.main.async {
                completition(Int(0))
            }
        }
    }
}

Answer 2

AVPlayer需要AVPlayerItem，在您的情况下是一个MP3文件。 AVFoundation有一个AVPlayerItemAccessLogEvent类，它可以为您提供 AverageAudioBitrate 。因此，您必须将AVPlayerItem传递给以下函数：

func getBitRate(playerItem : AVPlayerItem) -> Double{
        //var event : AVPlayerItemAccessLogEvent;
        var avgBitrate : Double = 0.0;
        for event in (playerItem.accessLog()?.events)!{
            if event.averageAudioBitrate>=0.0{
                avgBitrate = event.averageAudioBitrate;
            }
        }
        return avgBitrate;
    }

由于API是苹果暴露的，我认为这可能会解决您的问题。

得到比特率的音频项目迅速

2 个答案: