require 'rubygems'
# load FFMPEG bindings
require 'hornetseye_ffmpeg'
# load X.Org bindings
require 'hornetseye_xorg'
# load ALSA bindings
require 'hornetseye_alsa'
# include the namespace
include Hornetseye
# open a video file
input = AVInput.new 'sintel.mp4'
# open sound output with sampling rate of video
alsa = AlsaOutput.new 'default:0', input.sample_rate, input.channels
# read first audio frame
audio_frame = input.read_audio
# display images using width of 600 pixels and XVideo hardware acceleration
X11Display.show 600, :output => XVideoOutput do |display|
  # read an image
  img = input.read
  # while there is space in the audio output buffer ...   
  while alsa.avail >= audio_frame.shape[1]
    # ... write previous frame to audio buffer
    alsa.write audio_frame
    # read new audio frame
    audio_frame = input.read_audio
  end
  # compute difference of video clock to audio clock
  delay = input.video_pos - input.audio_pos + (alsa.delay + audio_frame.shape[1]).quo(alsa.rate)
  # suspend program in order to synchronise the video with the audio
  display.event_loop [delay, 0].max
  # display image
  img
end

#!/usr/bin/env ruby
require 'rubygems'
require 'hornetseye_v4l2'
require 'hornetseye_rmagick'
require 'hornetseye_xorg'
include Hornetseye
BOX = [220 ... 420, 140 ... 340]
input = V4L2Input.new
mask = MultiArray.bool(640, 480).fill!
mask[*BOX] = true
labels = ['reference', 'dragon', 'knight', 'camel']
labels.each do |label|
  X11Display.show(:title => label.capitalize) do
    img = input.read_ubytergb
    mask.conditional img, img >> 1
  end[*BOX].save_ubytergb "#{label}.jpg"
end

#!/usr/bin/env ruby
require 'rubygems'
require 'hornetseye_v4l2'
require 'hornetseye_rmagick'
require 'hornetseye_xorg'
include Hornetseye
PI = Math::PI
RAD = 2.0 * PI
VAL = 117.0
HBINS = 8
CBINS = 8
THRESHOLD = 32
N = 5
BOX = [220 ... 420, 140 ... 340]
class Node
  def hsv_hist(hbins = HBINS, cbins = CBINS)
    alpha = 2 * r.to_sint - g - b
    beta = Math.sqrt(3) / 2 * ( g.to_sint - b )
    h = ( (Math.atan2(beta, alpha) + PI) * (HBINS / RAD) ).to_int.clip 0 .. HBINS - 1
    c = ( Math.sqrt(alpha ** 2 + beta ** 2) * (CBINS / VAL) ).to_int.clip 0 .. CBINS - 1
    [h, c].histogram(hbins, cbins).to_int
  end
  def cmp(other)
    (self - other).abs / (self + other).major(1.0)
  end
end
input = V4L2Input.new
mask = MultiArray.bool(640, 480).fill!
mask[*BOX] = true
labels = ['reference', 'dragon', 'knight', 'camel']
hists = labels.collect do |object|
  MultiArray.load_ubytergb("#{object}.jpg").hsv_hist
end
history = ['reference'] * N
X11Display.show do
  img = input.read_ubytergb
  img_hist = img[*BOX].hsv_hist
  similarities = hists.collect { |hist| img_hist.cmp(hist).abs.sum }
  label = labels[similarities.index(similarities.min)]
  history = [label] + history[0 ... N - 1]
  if history == [label] * N
    system "echo '#{label}' | festival --tts" if label != 'reference'
  end
  history != ['reference'] * N ? mask.conditional(img, img >> 1) : img
end