Decode url then execute mpv with it.

mpv-ftp.go

package main

import (
	"fmt"
	"net/url"
	"os"
	"os/exec"
)

func main() {
	u, err := url.QueryUnescape(os.Args[1])
	if err != nil {
		fmt.Println("URL", os.Args[1], "error!")
		os.Exit(1)
	}
	cmd := exec.Command("mpv", u)
	cmd.Stdout = os.Stdout
	cmd.Stdin = os.Stdin
	cmd.Stderr = os.Stderr
	cmd.Run()
}