Ruby bindings for Libav/FFMPEG libraries.

ruby-ffmpeg is a Ruby extension for the Libav/FFMPEG set of libraries; libavformat, libavcodec, libavutil, and libswscale.

In contrast to many other Libav/FFMPEG-related gems, ruby-ffmpeg has been implemented as a C extension that calls into Libav/FFMPEG's set of libraries and is not a wrapper around the command line version. This allows much tighter integration with Ruby, finer control of the decoding process, and more efficient access of the media data. One example of such tight integration is that ruby-ffmpeg works with every IO object, from files, to string buffers, and even HTTP streams.

Some of ruby-ffmpeg's main features are:

• Data can be read from every Ruby IO object, e.g. files, string buffers, and HTTP streams
• Access to all important properties of streams, video frames, and audio frames
• Supports decoding of video and audio stream (subtitles will come soon)
• Allows resizing of video frames (NN, Linear, Cubic, etc.) and converting to different color spaces
• Allows resampling of audio data to different channels, sampling rate, and sample formats
• Integrates well with Ruby/GD2 (via VideoFrame#to_gd2)

ruby-ffmpeg requires the Libav/FFMPEG libraries to be installed on your system.

On OS X, MacPorts can be used to download and build the latest version of FFMPEG:

sudo port install ffmpeg-devel

The base version of the necessary Libav libraries can be installed via:

sudo apt-get install libavformat-dev libswscale-dev

Consult the the Ubuntu Community Help Wiki for details.

Once FFMPEG is available on the system, ruby-ffmpeg can be installed on top:

git clone git://github.com/tja/ruby-ffmpeg.git
cd ruby-ffmpeg
gem build ruby-ffmpeg.gemspec
gem install ruby-ffmpeg-0.2.0.gem

A very simple example to extract the first frame of a video and store it as RGB raw data:

require 'ruby-ffmpeg'

File.open("/path/to/video.mp4") do |io|
  FFMPEG::Reader.open(io) do |reader|
    video_stream = reader.streams.select { |s| s.type == :video }.first
    first_frame_as_rgb24 = video_stream.decode ^ video_stream.resampler(:rgb24)
    File.open("/path/to/output.raw", "wb") { |f| f.write(frame.data) }
  end
end

More tutorials and a full API documentation will come soon, but steer over to the examples folder for now.

ruby-ffmpeg is work-in-progress, which means:

• A lot of the functionality is still missing
• The API will most certainly change
• I am sure there are plenty of bugs

The short-term Todo list has been moved over to the Issue tracker on GitHub.