CODEWITHSUNDEEP
javascriptaudiotypesweb-audio-api
user2871915
user2871915

Reputation: 469

Web Audio- streaming file from server to client

I'm trying to stream audio from a server containing an audio file to a client using BinaryJS. My code was inspired by the code in this question: Playing PCM stream from Web Audio API on Node.js

Here's what my server code looks like:

// create a BinaryServer using BinaryJS
var BinaryServer = require('binaryjs').BinaryServer;
// gotta be able to access the filesystem
var fs = require('fs');

// create our server listening on a specific port
var server = BinaryServer({port: 8080});

// do this when a client makes a request
server.on('connection', function(client){
    // get the audio file
    var file = fs.createReadStream(__dirname + '/JDillaLife.mp3');

    // convert to int16
    var len = file.length;
    var buf = new Int16Array(len);

    while(len--){
        buf[len] = data[len]*0xFFFF;
    }

    var Stream = client.send();
    Stream.write(buf.buffer);

    console.log("Server contacted and file sent");
});
console.log('Server running on port 8080');

And my client code:

var Speaker = require('speaker');
var speaker = new Speaker({
    channels: 2,
    bitDepth: 32,
    sampleRate: 44100,
    signed: true
});

var BinaryClient = require('binaryjs').BinaryClient;
var client = BinaryClient('http://localhost:8080');
client.on('stream', function(stream, meta){
    stream.on('data', function(data){
        speaker.write(data);
    });
});

This is a very rough draft and I'm almost certain it won't play nicely right away, but right now it's throwing an error when I run that seems to take issue with the line var buf = new Int16Array(len);, and I'm not sure why this is happening. It says there's a "type error," but I'm not sure why this would happen when assigning a new object to an empty variable. I'm new to JS (and the whole untyped languages thing in general) so is this an issue with what I'm assigning?

Upvotes: 2

Views: 2096

Answers (1)

Oskar Eriksson
Oskar Eriksson

Reputation: 2641

I think the issue here is that you're accessing file.length, while file is a Stream object which I don't think have a length property. So what you're doing is basically saying 

 new Int16Array(undefined);

and hence the type error.

fs.createReadStream is documented here; https://nodejs.org/api/fs.html#fs_fs_createreadstream_path_options

You can use the Stream object to read data in chunks using stream.read(256), as documented here; https://nodejs.org/api/stream.html#stream_readable_read_size

Hopefully that gives you enough pointers to proceed!

Upvotes: 1

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