Fluent ffmpeg-API for node.js

This library abstracts the complex command-line usage of ffmpeg into a fluent, easy to use node.js module. In order to be able to use this module, make sure you have ffmpeg installed on your system (including all necessary encoding libraries like libmp3lame or libx264).

Now including input streaming support (means you can convert on-the-fly using an input- and an outputstream)!

Installation

Via npm: $ npm install fluent-ffmpeg

Or as a submodule: $ git submodule add git://github.com/schaermu/node-fluent-ffmpeg.git vendor/fluent-ffmpeg

Tests

To run unit tests, make sure have nodeunit installed on your system (currently, only npm-installed versions are supported).

$ nodeunit test

Make sure your ffmpeg installation is up-to-date to prevent strange assertion errors because of missing codecs/bugfixes.

Usage

You find a lot of usage examples (including a real-time streaming example using flowplayer and express!) in the examples folder.

Auto-calculation of video dimensions

Since ffmpeg does not support dynamic sizing of your movies, fluent-ffmpeg can do this job for you (using it's internal metadata-discovery). The following size formats are allowed to be passed to withSize:

• 320x? - Fixed width, calculate height
• ?x240 - Fixed height, calculate width
• 50% - percental resizing
• 320x240 - fixed size (plain ffmpeg way)

Auto-padding when converting aspect ratio

Using fluent-ffmpeg, you can auto-pad any video output when converting the aspect ratio. When converting from 4:3 to 16:9, padding is added to the left/right, when converting from 16:9 to 4:3, padding is added to top/bottom.

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('/path/to/your_movie.avi')
  .withAspect('4:3')
  .withSize('640x480')
  .applyPadding(true, 'white')
  .saveToFile('/path/to/your_target.avi', function(retcode, error){
    console.log('file has been converted succesfully');
  });

This command will auto-pad your 4:3 output video stream using a white background-color (default is black).

Simple conversion using preset

This example loads up a predefined preset in the preset folder (currently, fluent-ffmpeg ships with presets for DIVX, Flashvideo and Podcast conversions)

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('/path/to/your_movie.avi')
  .usingPreset('podcast')
  .saveToFile('/path/to/your_target.m4v', function(retcode, error){
    console.log('file has been converted succesfully');
  });

Conversion using chainable API

Using the chainable API, you are able to perform any operation using FFMPEG. the most common options are implemented using methods, for more advanced usages you can still use the addOption(s) method group.

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('/path/to/your_movie.avi')
  .withVideoBitrate(1024)
  .withVideoCodec('divx')
  .withAspectRatio('16:9')
  .withFps(24)
  .withAudioBitrate('128k')
  .withAudioCodec('libmp3lame')
  .withAudioChannels(2)
  .addOption('-vtag', 'DIVX')
  .toFormat('avi')
  .saveToFile('/path/to/your_target.avi', function(retcode, error){
    console.log('file has been converted succesfully');
  });

Creating thumbnails from a video file

One pretty neat feature is the ability of fluent-ffmpeg to generate any amount of thumbnails from your movies. The screenshots are taken at automatically determined timemarks using the following formula: (duration_in_sec * 0.9) / number_of_thumbnails.

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('/path/to/your_movie.avi')
  .withSize('150x100')
  .takeScreenshots(5, '/path/to/thumbnail/folder', function(err) {
    console.log('screenshots were saved')
  });

For more control, you can also set the timemarks for taking screenshots yourself (timemarks are always in seconds):

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('/path/to/your_movie.avi')
  .withSize('150x100')
  .takeScreenshots({
      count: 2,
      timemarks: [ '0.5', '1' ]
    }, '/path/to/thumbnail/folder', function(err) {
    console.log('screenshots were saved')
  });

Reading video metadata

Using a seperate object, you are able to access various metadata of your video file.

var ffmpegmeta = require('fluent-ffmpeg').Metadata;

// make sure you set the correct path to your video file
ffmpegmeta.get('/path/to/your_movie.avi', function(metadata) {
  console.log(require('util').inspect(metadata, false, null));
});

Creating a custom preset

To create a custom preset, you have to create a new file inside the lib/presets folder. The filename is used as the preset's name ([presetname].js). In order to make the preset work, you have to export a load function using the CommonJS module specifications:

exports.load = function(ffmpeg) {
  // your custom preset code
}

The ffmpeg parameter is a full fluent-ffmpeg object, you can use all the chaining-goodness from here on. For a good example for the possibilities using presets, check out lib/presets/podcast.js.

Setting custom child process niceness

You can adjust the scheduling priority of the child process used by ffmpeg, using renice (http://manpages.ubuntu.com/manpages/intrepid/man1/renice.1.html), like so:

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('./source.mp3')
  .renice(10)
  .withAudioCodec('libvorbis')
  .toFormat('ogg')
  .saveToFile('./target.ogg', function(retcode, error){
    console.log('file has been converted succesfully');
  });

Which will use a niceness of 10 (thus it has a lower scheduling priority than the node process and other processes, which default to a niceness of 0).

Setting an optional processing timeout

If you want to know for sure that the ffmpeg child process will not run for longer than a certain amount of time, you can set the optional second parameter of the ffmpeg object constructor to the timeout in milliseconds. An example of a process that will return an error string of 'timeout' if ffmpeg did not finish within 10 minutes:

var ffmpeg = require('fluent-ffmpeg');

var proc = new ffmpeg('./source.mp3', 10 * 60 * 1000)
  .withAudioCodec('libvorbis')
  .toFormat('ogg')
  .saveToFile('./target.ogg', function(retcode, error){
    if (retcode == ffmpeg.E_PROCESSTIMEOUT) {
      console.log('ffmpeg terminated because of timeout');
    }
  });

Contributing

Contributions in any form are highly encouraged and welcome! Be it new or improved presets, optimized streaming code or just some cleanup. So start forking!

License

(The MIT License)

Copyright (c) 2011 Stefan Schaermeli <schaermu@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.