combine.rb

class VideoPresenter
  def initialize(db_video, facebook_video)
    @facebook_id = db_video[:id]
    @age = facebook_video[:age]
  end
end

db_videos = [{ id: 42, name: 'Ion' }, { id: 43, name: 'Gheo' }]
facebook_videos = [{ facebook_id: 43, age: 42 }, { facebook_id: 44, age: 43 }]

Tuplet = Struct.new(:db, :facebook)

p db_videos
    .map { |db_video| Tuplet.new(db_video, facebook_videos.find { |h| h[:facebook_id] == db_video[:id] }) }
    .keep_if(&:facebook)
    .map { |tuplet| VideoPresenter.new(*tuplet) }