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1.0.6 • Public • Published

RecordRTC over Socket.io

npm downloads

npm install recordrtc-socketio
cd ./node_modules/recordrtc-socketio/
# to run it! 
node server.js
# now open:  http://localhost:9001 

There are some other NPM packages regarding RecordRTC:

This experiment:

  1. Records audio/video separately as wav/webm
  2. Emits both files using socket.io
  3. Socket.io server end receives emitted data; and writes wav/web files to disk
  4. Node.js code invokes ffmpeg to merge wav/webm in single "webm" file
  5. Socket.io server emits merged event; and passes-back the URL of the merged file

Client side stuff:

var socketio = io();
var files = {
    audio: {
        name: fileName + '.wav',
        type: 'audio/wav',
        dataURL: dataURL.audio
    video: {
        name: fileName + '.webm',
        type: 'video/webm',
        dataURL: dataURL.video
socketio.emit('message', files);

Server side code that captures above data:

io.sockets.on('connection', function(socket) {
    socket.on('message', function(data) {
        console.log('writing to disk');
        writeToDisk(data.audio.dataURL, data.audio.name);
        writeToDisk(data.video.dataURL, data.video.name);
        merge(socket, data.audio.name, data.video.name);

After merging; server side code that passes back the URL of the merged file:

socket.emit('merged', audioName.split('.')[0] + '-merged.webm');

Client-side code that receives merged-file URL:

socketio.on('merged', function (fileName) {
    cameraPreview.src = location.href + '/uploads/' + fileName;

Windows Batch File (merger.bat)

merger.bat file is executed to invoke ffmpeg functionalities on windows:

@echo off
"C:\ffmpeg\bin\ffmpeg.exe" -i %1 -i %2  %3

It is assumed that you already have installed ffmpeg on your system. Though, EXE file is hard-coded to "C:\ffmpeg\bin\ffmpeg.exe" however you can easily edit it according to your own installations.

.sh file

merger.sh file is executed to invoke ffmpeg functionalities on Mac/Linux/etc.

ffmpeg -i video-file.webm -i audio-file.wav -map 0:0 -map 1:0 output-file-name.webm

Using Linux; ffmpeg installation is super-easy! You can install DEVEL packages as well.

How to install ffmpeg on windows?

  1. Download ffmpeg and extract ZIP file
  2. Rename extracted directory to "ffmpeg"
  3. Right click over "My Computer" icon and select "Properties" context-menu option
  4. Select "Advance system settings" from top-left section
  5. Click "Environment Variables..." button from "Advanced" tab
  6. Click "New..." button and in the "Variable name" box, enter "Path".
  7. In the "Variable value" box, enter extracted directory full URI e.g. "C:\ffmpeg"
  8. Click "OK" and done!


How to install ffmpeg on Mac OSX?

Make sure you have homebrew installed. Then run following command:

brew install ffmpeg --with-libvpx --with-theora --whit-libogg --with-libvorbis

How to test?

In the node.js command prompt window; type node server. It will run socket.io server at port 9001. Then you can open index.html file on any webserver.


RecordRTC is released under MIT licence . Copyright (c) Muaz Khan.


npm i recordrtc-socketio

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