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hornetseye-qt4

Author: Jan Wedekind Copyright: 2010 License: GPL

Synopsis

This Ruby extension implements a Qt4 widget (compatible with qtruby4) for hardware accelerated video output.

Installation

This Ruby extension requires Qt4, QtRuby4 and the software scaling library. If you are running Debian or (K)ubuntu, you can install them like this:

$ sudo aptitude install libqt4-ruby1.8 qt4-dev-tools libswscale-dev libboost-dev

To install this Ruby extension, use the following command:

$ sudo gem install hornetseye-qt4

Alternatively you can build and install the Ruby extension from source as follows:

$ rake
$ sudo rake install

Usage

Simply run Interactive Ruby:

$ irb

You can use {Hornetseye::XvWidget} as shown below. This example implements a video player with a minimalistic GUI.

require 'rubygems'
require 'hornetseye_ffmpeg'
require 'hornetseye_alsa'
require 'hornetseye_qt4'
require 'Qt4'
VIDEO = ARGV.first
class Win < Qt::Widget
  slots 'seek(int)'
  def initialize
    super
    @screen = Hornetseye::XvWidget.new self
    @slider = Qt::Slider.new Qt::Horizontal
    layout = Qt::VBoxLayout.new self
    layout.addWidget @screen
    layout.addWidget @slider
    connect @slider, SIGNAL('valueChanged(int)'), self, SLOT('seek(int)')
    @seeking = true
    @video = nil
    @timer = 0
    start
    @slider.tracking = false
    @slider.minimum = 0
    @slider.single_step = 60
    @slider.page_step = 600
    if @video.duration
      @slider.maximum = @video.duration.to_i
    else
      @slider.maximum = ARGV[1] || 1
    end
    setWindowTitle 'XVideo'
  end
  def update_audio
    @audio_frame = @video.read_audio unless @audio_frame
    while @speaker.avail >= @audio_frame.shape[1]
      @speaker.write @audio_frame
      @audio_frame = @video.read_audio
    end
  end
  def update_video
    @screen.write @video.read_video
  end
  def timerEvent( e )
    begin
      update_audio
      update_video
      unless @slider.sliderDown
        @seeking = false
        p = @video.audio_pos.to_i
        @slider.maximum = p if p > @slider.maximum
        @slider.value = p
        @seeking = true
      end
      t = @video.audio_pos - @speaker.delay.quo( @speaker.rate )
      delay = [ 3.quo( 2 ) / @video.frame_rate,
                [ @video.video_pos - t, 0 ].max ].min
      killTimer @timer
      @timer = startTimer( ( delay * 1000 ).to_i )
    rescue Exception => e
      p e
      stop
    end
  end
  def start
    unless @video
      stop
      @video = Hornetseye::AVInput.new VIDEO
      @audio_frame = nil
      resize ( @video.width * @video.aspect_ratio ).to_i, @video.height
      @speaker = Hornetseye::AlsaOutput.new 'default:0',
                                            @video.sample_rate, @video.channels
      @timer = startTimer 0
    end
  end
  def stop
    @audio_frame = nil
    if @video
      @video.close
      @video = nil
    end
    if @speaker
      @speaker.close
      @speaker = nil
    end
    if @timer != 0
      killTimer @timer
      @timer = 0
      @screen.clear
    end
  end
  def seek( p )
    if @seeking
      begin
        start
        @audio_frame = nil
        @video.pos = p
        @speaker.drop
        @speaker.prepare
      rescue Exception => e
        p e
        stop
      end
    end
  end
end
app = Qt::Application.new ARGV
Win.new.show
app.exec
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