CarrierWave FFmpeg Uploader example

video_uploader.rb

class VideoUploader < CarrierWave::Uploader::Base
  include ::CarrierWave::Backgrounder::Delay
  include CarrierWave::FFmpeg

  RESOLUTIONS = [
      { version: :p1080, resolution: '1920x1080'}, 
      { version: :p720, resolution: '1280x720'}
    ]

  # Choose what kind of storage to use for this uploader:
  storage :file

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  before :store, :remember_cache_id
  after :store, :delete_tmp_dir

  # store! nil's the cache_id after it finishes so we need to remember it for deletion
  def remember_cache_id(new_file)
    @cache_id_was = cache_id
  end
  
  def delete_tmp_dir(new_file)
    # make sure we don't delete other things accidentally by checking the name pattern
    if @cache_id_was.present? && @cache_id_was =~ /\A[\d]{8}\-[\d]{4}\-[\d]+\-[\d]{4}\z/
      FileUtils.rm_rf(File.join(root, cache_dir, @cache_id_was))
    end
  end

  version :mp4 do
    process encode: [:mp4]
    
    def full_filename(for_file)
      super.chomp(File.extname(super)) + '.mp4'
    end

    RESOLUTIONS.each do |resolution|
      version resolution[:version], if: "bigger_than_#{resolution[:resolution]}?".to_sym

      version resolution[:version] do 
        process encode: [:mp4, resolution: resolution[:resolution]]
      end
    end
  end

  version :webm do
    process encode: [:webm]
    
    def full_filename(for_file)
      super.chomp(File.extname(super)) + '.webm'
    end

    RESOLUTIONS.each do |resolution|
      version resolution[:version], if: "bigger_than_#{resolution[:resolution]}?".to_sym

      version resolution[:version] do 
        process encode: [:webm, resolution: resolution[:resolution]]
      end
    end
  end

  version :ogv do
    process encode: [:ogv]
    
    def full_filename(for_file)
      super.chomp(File.extname(super)) + '.ogv'
    end

    RESOLUTIONS.each do |resolution|
      version resolution[:version], if: "bigger_than_#{resolution[:resolution]}?".to_sym

      version resolution[:version] do 
        process encode: [:ogv, resolution: resolution[:resolution]]
      end
    end
  end

  RESOLUTIONS.each do |resolution|
    define_method("bigger_than_#{resolution[:resolution]}?") do |argument|
      movie(argument.path).resolution > resolution[:resolution] ? true : false
    end
  end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  def extension_white_list
    %w(mp4 mov avi mkv 3gp mpg mpeg)
  end
end