Node.js: realtime conversion from jpeg images to video file - node.js

Question

I'm using node.js and through the socket.io library I receive chunks of data that are actually jpeg images. These images are frames of a realtime video captured from a remote webcam. I'm forced to stream the video as jpeg frames. I'm looking for a way to convert on the fly these jpeg images in a video file (mpeg 4 or mjpeg file). Does node have a library that can do this? I already took a look at the Node-fluent-FFMPEG library but the only examples given were about conversions of jpeg files to a video and not a conversion on the fly from a stream of jpeg images. Or alternatively, does ffmpeg for windows support a stream of jpeg images as input?

Answer 1

FFMPEG supports streams as inputs, as stated in the docs.
You can add any number of inputs to an Ffmpeg command. An input can
be [...] a readable stream
So for instance it supports using
ffmpeg().input(fs.createReadStream('/path/to/input3.avi'));
which creates a Readable stream from the file at '/path/to/input3.avi'.
I don't know anything about FFMPEG, but you may pull your messages coming from socket.io (messages may be a Buffer already) and wrap it with your own implementation of Readable stream.

Answer 2

I think you should look at videofy
var exec = require("child_process").exec;
var escape = require("shell-escape");
var debug = require("debug")("videofy");
var mkdirp = require("mkdirp");
var uid = require("uid2");
/*
* Expose videofy
*/
module.exports = videofy;
/**
* Convert `input` file to `output` video with the given `opts`:
*
* - `rate` frame rate [10]
* - `encoders` the video codec format, default is libx264
*
* #param {String} input
* #param {String} output
* #return
* #api public
*/
function videofy(input, output, opts, fn) {
if (!input) throw new Error('input filename required');
if (!output) throw new Error('output filename required');
var FORMAT = '-%05d';
// options
if ('function' == typeof opts) {
fn = opts;
opts = {};
} else {
opts = opts || {};
}
opts.rate = opts.rate || 10;
opts.codec = opts.codec || 'libx264';
// tmpfile(s)
var id = uid(10);
var dir = 'tmp/' + id;
var tmp = dir + '/tmp' + FORMAT + '.jpg';
function gc(err) {
debug('remove %s', dir);
exec('rm -fr ' + dir);
fn(err);
}
debug('mkdirp -p %s', dir);
mkdirp(dir, function(error) {
if (error) return fn(error);
// convert gif to tmp jpg
var cmd = ['convert', input, tmp];
cmd = escape(cmd);
debug('exec %s', cmd);
// covert jpg collection to video
exec(cmd, function(err) {
if (err) return gc(err);
var cmd = ['ffmpeg'];
cmd.push('-f', 'image2');
cmd.push('-r', String(opts.rate));
cmd.push('-i', tmp);
cmd.push('-c:v', String(opts.codec));
cmd.push(output);
cmd = escape(cmd);
debug("exec %s", cmd);
exec(cmd, gc);
});
});
}

Answer 3

Using require("child_process") you can use ffmpeg, or there are probably npm modules to help with this. ffmpeg will allow you to first take a list of jpegs and convert that to a video, second you can add a list (or just one) jpegs to the beginning or end of videos.