Class: EasyVideoUtils

Inherits:
Object
  • Object
show all
Extended by:
CommandHelper
Defined in:
lib/easyvideo_utils.rb

Instance Method Summary collapse

Methods included from CommandHelper

list, search

Constructor Details

#initialize(vid_in = nil, vid_out = 'video.mp4', out: vid_out, working_dir: '/tmp', debug: false) ⇒ EasyVideoUtils 



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# File 'lib/easyvideo_utils.rb', line 57

def initialize(vid_in=nil, vid_out='video.mp4', out: vid_out, 
               working_dir: '/tmp', debug: false)

  @file_out, @working_dir, @debug = out, working_dir, debug
  
  if vid_in.is_a? String then
    @file_in = vid_in
  elsif vid_in.is_a? Array
    @files_in = vid_in
  end

end

Instance Method Details

#add_audio(audio_file, show: false) ⇒ Object

Add an audio track to a video which contains no audio



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# File 'lib/easyvideo_utils.rb', line 72

def add_audio(audio_file, show: false)

  command = "ffmpeg -i #{@file_in} -i #{audio_file} -codec copy " + 
            "-shortest #{@file_out} -y"
  run command, show

end

#add_subtitles(file, show: false) ⇒ Object

To add subtitles, supply a .srt file



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# File 'lib/easyvideo_utils.rb', line 82

def add_subtitles(file, show: false)
     
  command = "ffmpeg -i #{@file_in} -i #{file} -c copy -c:s mov_" + 
            "text #{@file_out} -y"
  run command, show
  
end

#capture_desktop(show: false) ⇒ Object 



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# File 'lib/easyvideo_utils.rb', line 90

def capture_desktop(show: false)

  command = "ffmpeg -video_size 1024x768 -framerate 25 -f x11grab -i " + 
  ":0.0+0,0 #{@file_out}"
  run command, show

end

#concat(files = @files_in, show: false) ⇒ Object

Concatenate 2 or more videos

Notes:

  • Video must be of same format and codec

  • Only video with no audio is currently supported



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# File 'lib/easyvideo_utils.rb', line 104

def concat(files=@files_in, show: false)
  
  inputs = files.map {|file| "-i #{file}"}.join(' ')
  filter = files.map.with_index {|file,i| "[%s:v]" % i}.join(' ')
  
  command = "ffmpeg #{inputs} \ " + 
  " -filter_complex \"#{filter} concat=n=#{files.length}:v=1 [v]\" \ " + 
  " -map \"[v]\"  #{@file_out}"

  run command, show
  
end

#duration ⇒ Object

Duration returned in seconds



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# File 'lib/easyvideo_utils.rb', line 119

def duration()
  
  s = `exiftool #{@file_in}`
  puts 's: ' + s.inspect if @debug
  r = s[/Duration.*(\d{1,2}:\d{2}:\d{2})/,1]

  puts 'r: ' + r.inspect if @debug    
  
  if r then
    a = r.split(':').map(&:to_i)
    return Subunit.new(units={minutes:60, hours:60, seconds: 0}, a).to_i
  end
  
  puts 'r: ' + r.inspect if @debug
  s[/Duration.*: (\d+\.\d+) s/,1].to_f

end

#extract_images(show: false, ext: '.png', rate: 1) ⇒ Object

Extract images from the video

switches used:

-r – Set the frame rate. I.e the number of frames to be extracted into images per second. -f – Indicates the output format i.e image format in our case.



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# File 'lib/easyvideo_utils.rb', line 144

def extract_images(show: false, ext: '.png', rate: 1)
  command = "ffmpeg -i #{@file_in} -r #{rate} -f image2 image-%2d#{ext}"
  run command, show
end

#play(show: false) ⇒ Object 



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# File 'lib/easyvideo_utils.rb', line 149

def play(show: false)
  command = "mplayer #{@file_out}"
  run command, show
end

#preview(show: false) ⇒ Object 



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# File 'lib/easyvideo_utils.rb', line 154

def preview(show: false)
  command = "ffplay #{@file_out}"
  run command, show
end

#remove_audio(show: false) ⇒ Object 



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# File 'lib/easyvideo_utils.rb', line 159

def remove_audio(show: false)
  command = "ffmpeg -i #{@file_in} -an #{@file_out}"
  run command, show
end

#remove_video(show: false) ⇒ Object

removes the video track which leaves the audio track e.g. ffmpeg -i input.mp4 -vn output.mp3



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# File 'lib/easyvideo_utils.rb', line 167

def remove_video(show: false)
  command = "ffmpeg -i #{@file_in} -vn #{@file_out}"
  run command, show
end

#resize(scale = '720', show: false) ⇒ Object Also known as: scale

Resize avi to 720p



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# File 'lib/easyvideo_utils.rb', line 174

def resize(scale='720', show: false)
  command = "ffmpeg -i #{@file_in} -vf scale=\"#{scale}:-1\" #{@file_out} -y"
  run command, show
end

#slowdown(speed = :x2, show: false) ⇒ Object

slow down a video

note: presentation timestamp (PTS) ‘x2’ = half speed; ‘x4’ = quarter speed



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# File 'lib/easyvideo_utils.rb', line 186

def slowdown(speed=:x2, show: false)
  
  factor = {x1_5: 1.5, x2: 2.0, x4: 4.0}[speed.to_s.sub('.','_').to_sym]
  command = "ffmpeg -i #{@file_in} -vf \"setpts=#{factor}*PTS\" " + 
      "#{@file_out} -y"
  run command, show
  
end

#speedup(speed = :x2, show: false) ⇒ Object

speed up a video

note: presentation timestamp (PTS) ‘x2’ = double speed; ‘x4’ = quadruple speed



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# File 'lib/easyvideo_utils.rb', line 200

def speedup(speed=:x2, show: false)
  
  h = {x1_5: 0.75, x2: 0.5, x4: 0.25, x6: 0.166, x8: 0.125, x16: 0.0625, 
       x32: 0.03125, x64: 0.015625}
  factor = h[speed.to_s.sub('.','_').to_sym]
  command = "ffmpeg -i #{@file_in} -vf \"setpts=#{factor}*PTS\" " + 
      "#{@file_out} -y"
  run command, show
  
end

#transcode(show: false) ⇒ Object Also known as: convert

Transcodes avi -> mp4



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# File 'lib/easyvideo_utils.rb', line 213

def transcode(show: false)
  
  command = "ffmpeg -i #{@file_in} #{@file_out} -y"
  run command, show    

end

#trim(start_time, end_time, show: false) ⇒ Object

Trim the start and end of the video times are expressed in human time format e.g. ‘1m 4s’, ‘2m 30’



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# File 'lib/easyvideo_utils.rb', line 225

def trim(start_time, end_time, show: false)
      
  t1, t2 = [start_time, end_time].map do |s|

    "%02d:%02d:%02d" % (s.sub(/m/,'\00s').split(/\D/).reverse + [0,0])\
                        .take(3).reverse

  end
  
  command = "ffmpeg -i #{@file_in} -ss #{t1} -t #{t2} -async 1 " + 
            "#{@file_out} -y"
  run command, show
  
end