ffmpeg-ruby
Summary
ffmpeg-ruby is a ruby C extension binding to ffmpeg/libav* library.
It's main purpose is to extract frame in order to make video thumbnails. It also give access to main video attributes (frame rate, bit rate, duration, codecs, ...)
So, it doesn't support encoding (at least for now).
Installation
Download latest sources of ffmpeg :
wget http://ffmpeg.mplayerhq.hu/ffmpeg-export-snapshot.tar.bz2
tar xjvf ffmpeg-export-snapshot.tar.bz2
cd ffmpeg-export-20*
Configure, optionally with some prefix :
./configure --prefix=/opt/ffmpeg --enable-pthreads --enable-shared --enable-gpl
make
sudo make install
You can now continue with ffmpeg-ruby.
git clone git://github.com/gwik/ffmpeg-ruby.git
cd ffmpeg-ruby
gem build ./ffmpeg-ruby.gemspec
sudo gem install ./ffmpeg-ruby-0.1.0.gem -- --with-ffmpeg-dir=/opt/ffmpeg
You can now test it :
irb
>> require 'rubygems'
=> false
>> require 'ffmpeg'
=> true
>> FFMPEG
=> FFMPEG
Tutorial
ffmpeg-ruby does not have real document YET (I promise it will change soom). You can take a look a specs for in depth usage.
Here is basic usage.
Video attributes
require 'rubygems'
require 'ffmpeg'
video = FFMPEG::InputFormat.new('alligator.mp4')
# => #<FFMPEG::InputFormat:0x5fa3c0>
video.public_methods - Object.public_instance_methods
# => ["bit_rate", "filename", "duration", "has_stream_with_codec_type?", "first_video_stream", "human_duration", "has_video?", "video_stream_count", "streams", "has_audio?", "first_audio_stream", "audio_stream_count"]Streams
video.first_video_stream.public_methods - Object.public_instance_methods
# => ["position", "duration", "index", "codec", "decode_frame", "seek"]Seeking in stream
video.first_video_stream.seek(10)
video.first_video_stream.position
# => 10.2333333333333As you can see, seeking is not very precise.
Extracting frame
frame = video.first_video_stream.decode_frame
# => #<FFMPEG::Frame:0x5c9874>
"frame size #{frame.width}x#{frame.height}"
# => "frame size 240x176"Animated GIF example with RMagick
See animated_gif_example.rb