Class: Aspera::Preview::Utils

Inherits:
Object
  • Object
show all
Defined in:
lib/aspera/preview/utils.rb

Class Method Summary collapse

Class Method Details

.check_tools(skip_types = []) ⇒ Object

check that external tools can be executed



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# File 'lib/aspera/preview/utils.rb', line 29

def check_tools(skip_types=[])
  tools_to_check = EXTERNAL_TOOLS.dup
  tools_to_check.delete(:unoconv) if skip_types.include?(:office)
  # Check for binaries
  tools_to_check.each do |command_symb|
    external_command(command_symb, ['-h'])
  end
end

.external_command(command_symb, command_args) ⇒ Object

execute external command one could use “system”, but we would need to redirect stdout/err

Returns:

  • true if su



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# File 'lib/aspera/preview/utils.rb', line 41

def external_command(command_symb, command_args)
  raise "unexpected command #{command_symb}" unless EXTERNAL_TOOLS.include?(command_symb)
  # build command line, and quote special characters
  command = command_args.clone.unshift(command_symb).map{|i| shell_quote(i.to_s)}.join(' ')
  Log.log.debug{"cmd=#{command}".blue}
  # capture3: only in ruby2+
  if Open3.respond_to?(:capture3)
    stdout, stderr, exit_status = Open3.capture3(command)
  else
    stderr = '<merged with stdout>'
    stdout = %x(#{command} 2>&1)
    exit_status = $CHILD_STATUS
  end
  if BASH_EXIT_NOT_FOUND.eql?(exit_status)
    raise "Error: #{command_symb} is not in the PATH"
  end
  unless exit_status.success?
    Log.log.error{"command line: #{command}"}
    Log.log.error{"Error code: #{exit_status}"}
    Log.log.error{"stdout: #{stdout}"}
    Log.log.error{"stderr: #{stderr}"}
    raise "#{command_symb} error #{exit_status}"
  end
  return {status: exit_status, stdout: stdout}
end

.ffmpeg(a) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 67

def ffmpeg(a)
  raise 'error: hash expected' unless a.is_a?(Hash)
  # input_file,input_args,output_file,output_args
  a[:gl_p] ||= [
    '-y', # overwrite output without asking
    '-loglevel', 'error' # show only errors and up
  ]
  a[:in_p] ||= []
  a[:out_p] ||= []
  raise "wrong params (#{a.keys.sort})" unless i[gl_p in_f in_p out_f out_p].eql?(a.keys.sort)
  external_command(:ffmpeg, [a[:gl_p], a[:in_p], '-i', a[:in_f], a[:out_p], a[:out_f]].flatten)
end

.ffmpeg_fmt(temp_folder) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 90

def ffmpeg_fmt(temp_folder)
  return File.join(temp_folder, TEMP_FORMAT)
end

.get_tmp_num_filepath(temp_folder, file_number) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 94

def get_tmp_num_filepath(temp_folder, file_number)
  return File.join(temp_folder, format(TEMP_FORMAT, file_number))
end

.shell_quote(argument) ⇒ Object

returns string with single quotes suitable for bash if there is any bash meta-character



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# File 'lib/aspera/preview/utils.rb', line 23

def shell_quote(argument)
  return argument unless argument.chars.any?{|c|BASH_SPECIAL_CHARACTERS.include?(c)}
  return "'" + argument.gsub(/'/){|_s| "'\"'\"'"} + "'"
end

.video_blend_frames(temp_folder, index1, index2) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 105

def video_blend_frames(temp_folder, index1, index2)
  img1 = get_tmp_num_filepath(temp_folder, index1)
  img2 = get_tmp_num_filepath(temp_folder, index2)
  count = index2 - index1 - 1
  1.upto(count) do |i|
    percent = i * 100 / (count + 1)
    filename = get_tmp_num_filepath(temp_folder, index1 + i)
    external_command(:composite, ['-blend', percent, img2, img1, filename])
  end
end

.video_dump_frame(input_file, offset_seconds, scale, output_file, index = nil) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 116

def video_dump_frame(input_file, offset_seconds, scale, output_file, index=nil)
  output_file = get_tmp_num_filepath(output_file, index) unless index.nil?
  ffmpeg(
    in_f: input_file,
    in_p: ['-ss', offset_seconds],
    out_f: output_file,
    out_p: ['-frames:v', 1, '-filter:v', "scale=#{scale}"])
  return output_file
end

.video_dupe_frame(temp_folder, index, count) ⇒ Object 



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# File 'lib/aspera/preview/utils.rb', line 98

def video_dupe_frame(temp_folder, index, count)
  input_file = get_tmp_num_filepath(temp_folder, index)
  1.upto(count) do |i|
    FileUtils.ln_s(input_file, get_tmp_num_filepath(temp_folder, index + i))
  end
end

.video_get_duration(input_file) ⇒ Object

Returns Float in seconds.

Returns:

  • Float in seconds



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# File 'lib/aspera/preview/utils.rb', line 81

def video_get_duration(input_file)
  result = external_command(:ffprobe, [
    '-loglevel', 'error',
    '-show_entries', 'format=duration',
    '-print_format', 'default=noprint_wrappers=1:nokey=1', # cspell:disable-line
    input_file])
  return result[:stdout].to_f
end