Error getting MP3 file duration

[jinhailli]

func Mp3Time(){

byteBody, anyErr := ioutil.ReadFile("./test.mp3")
if anyErr != nil {
	fmt.Printf("ReadFile err:%v\n", anyErr)
	return
}

fmt.Printf("len byteMp3:%v\n", len(string(byteBody)))

streamer, format, anyErr := mp3.Decode(ioutil.NopCloser(bytes.NewBuffer(byteBody)))
if anyErr != nil {
	fmt.Printf("Decode anyErr:%v", anyErr)
	return
}


defer streamer.Close()
fmt.Printf("streamerMp3.Len():%v\n", streamer.Len())

length := format.SampleRate.D(streamer.Len())

nTime := int64(length.Round(time.Millisecond).Seconds() * 1000)

fmt.Printf("time:%v\n", nTime)

} The result is： len byteMp3:2219090 streamerMp3.Len():0 time:0

[tryffel]

I think this is actually due to a limitation in haijmehoshi/go-mp3, being the fact that the constructor mp3.Decode(rc) actually requires io.Seeker interface in order to implement Len() and seeking. Maybe it could be mentioned in documentation. reference