How to play audio stream chunks recorded with WebRTC?

问题

I'm trying to create an experimental application that streams audio in real time from client 1 to client 2.

So following some tutorials and questions about the same subject, I used WebRTC and binaryjs. So far this is what I get

1- Client 1 and Client 2 have connected to BinaryJS to send/receive data chunks.

2- Client 1 used WebRTC to record audio and gradually send it to BinaryJS

3- Client 2 receives the chunks and try to play them.

Well I'm getting an error in the last part. This is the error message I get:

Uncaught RangeError: Source is too large

at Float32Array.set (native)

And this is the code:

Client 1

var WSClient;
var AudioStream;

function load(){
    var session = {
        audio: true,
        video: false
    };

    var recordRTC = null;

    navigator.getUserMedia(session, startRecording, onError);
    WSClient = new BinaryClient('ws://localhost:9001');
    WSClient.on('open',function(){
        console.log('client opened')
        AudioStream = WSClient.createStream();
    })
}

function startRecording(stream){
    var context = new AudioContext();
    var audio_input = context.createMediaStreamSource(stream);
    var buffer_size = 2048;

    var recorder = context.createScriptProcessor(buffer_size, 1, 1);

    recorder.onaudioprocess = function(e){
        console.log('chunk')
        var left = e.inputBuffer.getChannelData(0);
        AudioStream.write(left);
    };

    audio_input.connect(recorder);
    recorder.connect(context.destination);
}

Client 2

var WSClient;
var audioContext;
var sourceNode;

function load(){
    audioContext = new AudioContext();
    sourceNode = audioContext.createBufferSource();
    sourceNode.connect(audioContext.destination);

    sourceNode.start(0);

    WSClient = new BinaryClient('ws://localhost:9001');

    WSClient.on('open',function(){
        console.log('client opened');
    });

    WSClient.on('stream', function(stream, meta){
        // collect stream data
        stream.on('data', function(data){
            console.log('received chunk')
            var integers = new Int16Array(data);
            var audioBuffer = audioContext.createBuffer(1, 2048, 4410);
            audioBuffer.getChannelData(0).set(integers); //appearently this is where the error occurs
            sourceNode.buffer = audioBuffer;
        });
    });
}

Server

var wav = require('wav');
var binaryjs = require('binaryjs');

var binaryjs_server = binaryjs.BinaryServer;

var server = binaryjs_server({port: 9001});

server.on('connection', function(client){
    console.log('server connected');

    var file_writter = null;

    client.on('stream', function(stream, meta){
        console.log('streaming', server.clients)
        //send to other clients
        for(var id in server.clients){
            if(server.clients.hasOwnProperty(id)){
                var otherClient = server.clients[id];
                if(otherClient != client){
                    var send = otherClient.createStream(meta);
                    stream.pipe(send);
                }
            }
        }
    });

    client.on('close', function(stream){
        console.log('client closed')
        if(file_writter != null) file_writter.end();
    });
});

The error occurs here:

audioBuffer.getChannelData(0).set(integers);

So I have two questions:

Is it possible to send the chunks I captured in client 1 and then reproduce them in client 2?

What is the deal with the error I'm having?

Thanks guys!

@edit 1

Since i'm getting code snippets from other questions I'm still trying to understand it. I commented the line in client 2 code that creates an Int16Array and I now get a different error (but I don't know which version of the code is more correct):

Uncaught DOMException: Failed to set the 'buffer' property on 'AudioBufferSourceNode': Cannot set buffer after it has been already been set

Probably because I'm setting it everytime I get a new chunk of data.

回答1:

The DOMException about AudioBufferSourceNode means you need to create a new AudioBufferSourceNode for every new Audiobuffer that you're creating. So something like

sourceNode = new AudioBufferSourceNode(audioContext, {buffer: audioBuffer})

And an AudioBuffer has Float32Arrays. You need to convert your Int16Array to a Float32Array before assigning it to an AudioBuffer. Probably good enough to divide everything by 32768.

来源：https://stackoverflow.com/questions/47274120/how-to-play-audio-stream-chunks-recorded-with-webrtc