<script>
    function PlayerRoduzir(id) {
        var id;
        change("https://api.xxxxxx.com/tracks/" + id +".mp3");
        var button1 = document.getElementById("play_" + id).style.display = "none";
        var button2 = document.getElementById("stop_" + id).style.display = "";
      }

    function PlayerParar(id){
        var id;
      var audio = document.getElementById("player");
      var source = document.getElementById("mp3_src");
      var button1 = document.getElementById("play_" + id).style.display = "";
      var button2 = document.getElementById("stop_" + id).style.display = "none";
      audio.pause();
    }
</script>

<?php
echo "<button type='button' id='play_".$id."' onClick='PlayerRoduzir(".$id.");' class='btn btn-info'><i class="fa fa-play-circle-o" aria-hidden="true"></i></button> ";
echo "<button type='button' style='display: none;' id='stop_".$id."' onClick='PlayerParar(".$id.");' class='btn btn-danger'><i class="fa fa-stop" aria-hidden="true"></i></button> ";
?>