variables - Play audio file from string in JavaScript - Stack Overflow

I have the contents of an mp3 file saved as a variable, (this isn't meant to be practical, just for a little project of mine), and I wish to play the contents of this variable as an audio file. This would be a simple task with something like node, but unfortunately I must do this entirely client side.

Please note I can not just save the content of the string as an mp3 file, I need to be able to play it from a variable.

I have looked into this, but from what I have found, it appears that this can not be done. If any of you have a solution, I would appreciate hearing it.

I have the contents of an mp3 file saved as a variable, (this isn't meant to be practical, just for a little project of mine), and I wish to play the contents of this variable as an audio file. This would be a simple task with something like node, but unfortunately I must do this entirely client side.

Please note I can not just save the content of the string as an mp3 file, I need to be able to play it from a variable.

I have looked into this, but from what I have found, it appears that this can not be done. If any of you have a solution, I would appreciate hearing it.

• javascript
• variables
• client
• html5-audio

Share Improve this question Follow asked May 13, 2018 at 1:36 Inigo MantoyaInigo Mantoya 67133 gold badges99 silver badges1414 bronze badges 2

• What sort of encoding? – CertainPerformance Commented May 13, 2018 at 1:39
• .mp3 files are plex encoded binary files, how exactly does one store that as a string in javascript? Anything can be done with enough time, but if you really have .mp3 as a string, you would probably have to read the specifications for the MP3 format, figure out how to get the header and the billions of frames that make up a pressed audio file like that. – adeneo Commented May 13, 2018 at 1:49

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1 Answer 1

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This is not very practical, as you're going to get very high memory footprints within the JS engine and will likely cause unnecessary garbage collection... but it is possible to a base64 encode the MP3 which can then be fed into the src attribute of an <audio> tag.

Because it is unrealistically to provide a base64 encoded MP3 in an answer here I'll provide a Fiddle: https://jsfiddle/4t6bg95z/1/

But the gist of the code can be something like:

var audio = document.getElementById('audio');
audio.src = "data:audio/mp3;base64,..."; //This is a base64 encoded string of an MP3 file

window.beep = function() {
    audio.play();
}

Obviously, it is much better practice to provide a URL to the audio source instead, as that's the intended usage of the Audio API.