Class: Erika::Video

Inherits:
Object
  • Object
show all
Defined in:
lib/erika/video.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(image: nil, full_path: '') ⇒ Video

Returns a new instance of Video.



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# File 'lib/erika/video.rb', line 6

def initialize image: nil, full_path: ''
  @image     = image
  @full_path = full_path
  @temp_path = "#{Erika::Default.temp.video_dir}/#{image&.formatted_index}.mp4"
end

Instance Attribute Details

#full_path ⇒ Object (readonly)

Returns the value of attribute full_path.



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# File 'lib/erika/video.rb', line 4

def full_path
  @full_path
end

#image ⇒ Object

Returns the value of attribute image.



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# File 'lib/erika/video.rb', line 3

def image
  @image
end

#temp_path ⇒ Object (readonly)

Returns the value of attribute temp_path.



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# File 'lib/erika/video.rb', line 4

def temp_path
  @temp_path
end

Class Method Details

.merge(images) ⇒ Object 



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# File 'lib/erika/video.rb', line 78

def merge(images)
  images.each do |image|
    cmd = %Q{echo file '#{image.formatted_index}.mp4' >> #{Erika::Default.temp.video_list}}
    Erika::Runner.(cmd)
  end
  
  cmd = %Q{ffmpeg -y -f concat -safe 0 -i #{Erika::Default.temp.video_list} -c copy #{Erika::Default.temp.filename}}
  Erika::Runner.(cmd)
end

Instance Method Details

#mix(audio: Erika::Audio.new) ⇒ Object 



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# File 'lib/erika/video.rb', line 12

def mix(audio: Erika::Audio.new)
  length_of_video = Erika::Config.slide_duration * Erika::Config.no_of_images.to_f
  length_of_audio = Erika::Runner.(%Q{ffprobe -i #{Erika::Config.audio} -show_format -v quiet | sed -n 's/duration=//p'}).chomp.to_f
  num_of_loops    = (length_of_video / length_of_audio).ceil
  
  if length_of_video > length_of_audio
    # Generate a new audio file looped so that it can cover the video fully
    cmd = %Q{ffmpeg -lavfi "amovie=#{audio.full_path}:loop=#{num_of_loops }" #{Erika::Default.temp.audio_filename}}
    Erika::Runner.(cmd)
  else
    Erika::Runner.("cp #{audio.full_path} #{Erika::Default.temp.audio_filename}")
  end
  
  # ffmpeg has the promising -loop_input flag, but it doesn't support audio inputs yet.
  # Add Background Music to the Slideshow
  cmd = [
      ['ffmpeg'],
      ['-y'],
      ['-i', full_path], # video file as 0th input
      ['-i', Erika::Default.temp.audio_filename], # audio file as 1st input
      [%Q{-vf "subtitles=#{Erika::Default.temp.subtitle_filename}:force_style='Fontsize=#{Erika::Config.caption.font_size},FontName=#{Erika::Config.caption.font},PrimaryColour=#{Erika::Config.caption.font_color}'"}],
      ['-map', '0:v'], # Selects the video from 0th input
      ['-map', '1:a'], # Selects the audio from 1st input
      ['-ac', '2'], # Audio channel manipulation https://trac.ffmpeg.org/wiki/AudioChannelManipulation
      ['-shortest'], # will end the output file whenever the shortest input ends.
      [%Q{"#{Erika::Config.output_file}"}]
  ].flatten.join(' ')

  Erika::Runner.(cmd)
end

#save ⇒ Object 



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# File 'lib/erika/video.rb', line 43

def save
  
  # def _create_video_
  #   filename           = image.split('/').last.split('.').first
  later_start_time   = Erika::Config.slide_duration - Erika::Config.slide_animation_duration
  earlier_start_time = 0
  
  if image.index == 0
    # no fading in beginning, but fadeout at end
    transition = %Q{fade=t=out:st=#{later_start_time}:d=#{Erika::Config.slide_animation_duration}}
  elsif image.index == Erika::Config.no_of_images - 1
    # the should be fading in beginning, but no fadeout at end
    transition = %Q{fade=t=in:st=#{earlier_start_time}:d=#{Erika::Config.slide_animation_duration}}
  else
    transition = %Q{fade=t=in:st=#{earlier_start_time}:d=#{Erika::Config.slide_animation_duration},fade=t=out:st=#{later_start_time}:d=#{Erika::Config.slide_animation_duration}}
  end
  filter = %Q{"#{transition}"}
  
  cmd = [
      ['ffmpeg'],
      ['-y', ''],
      ['-loop', '1'],
      ['-i', image.temp_path],
      ['-vf', filter],
      ['-c:v', 'mpeg2video'],
      ['-t', Erika::Config.slide_duration],
      ['-q:v', '1'],
      ['-b:a 32k'],
      [%Q{"#{temp_path}"}]
  ].join(' ')
  
  Erika::Runner.(cmd)
end