Loading mp3 as ArrayBuffer using local file for Web Audio

Question

i wish load a mp3 local file and next using a library for processing, i cant use XMLHttpRequest, then i use the next code for read a local mp3 file:

<!DOCTYPE html>
<html>
    <head>
    </head>
    <body onload="carga();">
        <input id="audio_file" type="file" accept="audio/*" />
        <audio id="audio_player" />
        <script>
            function carga() {

                audio_file.onchange = function(){
                var files = this.files;
                console.log(files);
                alert(files);
                var file = URL.createObjectURL(files[0]); 
                console.log(file);
                alert(file);
                audio_player.src = file; 
                audio_player.play();
                                                };
            }
        </script>
    </body>
</html>

but XMLHttpRequest return ArrayBuffer, and my code return a FileList, i need a ArrayBuffer for my next processing, how i can load a local mp3 file as a ArrayBuffer?

score 11 · Answer 1 · answered Aug 24 '15 at 01:26

On modern Browser you can use a FileReader and its method readAsArrayBuffer.

  document.querySelector('input').onchange = function(){
      var fileReader  = new FileReader;
      fileReader.onload = function(){
         var arrayBuffer = this.result;
         snippet.log(arrayBuffer);
         snippet.log(arrayBuffer.byteLength);
         }
      fileReader.readAsArrayBuffer(this.files[0]);

      var url = URL.createObjectURL(this.files[0]); 
      audio_player.src = url; 
      audio_player.play();
    };

<!-- Provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>
<input id="audio_file" type="file" accept="audio/*" />
<audio id="audio_player" />

Loading mp3 as ArrayBuffer using local file for Web Audio

1 Answers1