class Lolcommits::CaptureMacAnimated

Public Instance Methods

capture() click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 4
def capture
  # make a fresh frames directory
  FileUtils.rm_rf(frames_location)
  FileUtils.mkdir_p(frames_location)

  # capture the raw video with videosnap
  system_call "#{videosnap_bin} -s 240 #{capture_device_string}#{capture_delay_string}-t #{animated_duration} --no-audio #{video_location} > /dev/null"
  if File.exists?(video_location)
    # convert raw video to png frames with ffmpeg
    system_call "ffmpeg -v quiet -i #{video_location} -t #{animated_duration} #{frames_location}/%09d.png"

    # use fps to set delay and number of frames to skip (for lower filesized gifs)
    fps   = video_fps(video_location)
    skip  = frame_skip(fps)
    delay = frame_delay(fps, skip)
    debug "Capturer: anaimated gif choosing every #{skip} frames with a frame delay of #{delay}"

    # create the looping animated gif from frames (picks nth frame with seq)
    seq_command = "seq -f #{frames_location}/%09g.png 1 #{skip} #{Dir["#{frames_location}/*"].length}"
    # convert to animated gif with delay and gif optimisation
    system_call "convert -layers OptimizeTransparency -delay #{delay} -loop 0 `#{seq_command}` -coalesce #{snapshot_location}"
  end
end

Private Instance Methods

capture_delay_string() click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 66
def capture_delay_string
  "-w '#{capture_delay}' " if capture_delay.to_i > 0
end
capture_device_string() click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 62
def capture_device_string
  "-d '#{capture_device}' " if capture_device
end
frame_delay(fps, skip) click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 34
def frame_delay(fps, skip)
  # calculate frame delay
  delay = ((100.0 * skip)/fps.to_f).to_i
  delay < 6 ? 6 : delay # hard limit for IE browsers
end
frame_skip(fps) click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 46
def frame_skip(fps)
  # of frames to skip depends on movie fps
  case(fps)
  when 0..15
    2
  when 16..28
    3
  else
    4
  end
end
system_call(call_str, capture_output = false) click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 29
def system_call(call_str, capture_output = false)
  debug "Capturer: making system call for \n #{call_str}"
  capture_output ? `#{call_str}` : system(call_str)
end
video_fps(file) click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 40
def video_fps(file)
  # inspect fps of the captured video file (default to 29.97)
  fps = system_call("ffmpeg -i #{file} 2>&1 | sed -n \"s/.*, \\(.*\\) fp.*/\\1/p\"", true)
  fps.to_i < 1 ? 29.97 : fps.to_f
end
videosnap_bin() click to toggle source
# File lib/lolcommits/capture_mac_animated.rb, line 58
def videosnap_bin
  File.join(Configuration::LOLCOMMITS_ROOT, 'vendor', 'ext', 'videosnap', 'videosnap')
end