func convertToOpus(rd io.Reader) (io.Reader, error) {

    // Convert to a format that can be passed to dca-rs
    ffmpeg := exec.Command("ffmpeg", "-i", "pipe:0", "-f", "s16le", "-ar", "48000", "-ac", "2", "pipe:1")
    ffmpeg.Stdin = rd
    ffmpegout, err := ffmpeg.StdoutPipe()
    if err != nil {
        return nil, err
    }

    // Convert to opus
    dca := exec.Command("./dca-rs", "--raw", "-i", "pipe:0")
    dca.Stdin = ffmpegout
    dcaout, err := dca.StdoutPipe()
    dcabuf := bufio.NewReaderSize(dcaout, 1024)
    if err != nil {
        return nil, err
    }

    // Start ffmpeg
    err = ffmpeg.Start()
    if err != nil {
        return nil, err
    }

    // Start dca-rs
    err = dca.Start()
    if err != nil {
        return nil, err
    }

    // Returns a stream of opus data
    return dcabuf, nil
}