Module: Spaceship::Utilities

Defined in:
spaceship/lib/spaceship/du/utilities.rb

Overview

Set of utility methods useful to work with media files

Class Method Summary collapse

Class Method Details

.content_type(path) ⇒ Object

Identifies the content_type of a file based on its file name extension. Supports all formats required by DU-UTC right now (video, images and json)



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 10

def content_type(path)
  supported_file_types = {
    '.jpg' => 'image/jpeg',
    '.jpeg' => 'image/jpeg',
    '.png' => 'image/png',
    '.geojson' => 'application/json',
    '.mov' => 'video/quicktime',
    '.m4v' => 'video/mp4',
    '.mp4' => 'video/mp4',
    '.txt' => 'text/plain',
    '.pdf' => 'application/pdf',
    '.doc' => 'application/msword',
    '.docx' => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
    '.rtf' => 'application/rtf',
    '.pages' => 'application/x-iwork-pages-sffpages',
    '.xls' => 'application/vnd.ms-excel',
    '.xlsx' => 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
    '.numbers' => 'application/x-iwork-numbers-sffnumbers',
    '.rar' => 'application/x-rar-compressed',
    '.plist' => 'application/xml',
    '.crash' => 'text/x-apport',
    '.avi' => 'video/x-msvideo',
    '.zip' => 'application/zip'
  }

  extension = File.extname(path.downcase)
  return supported_file_types[extension] if supported_file_types[extension]
  raise "Unknown content-type for file #{path}"
end

.grab_video_preview(video_path, timestamp, dimensions) ⇒ Object

Grabs a screenshot from the specified video at the specified timestamp using ‘ffmpeg`



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 62

def grab_video_preview(video_path, timestamp, dimensions)
  width, height = dimensions
  require 'tempfile'
  tmp = Tempfile.new(['video_preview', ".jpg"])
  file = tmp.path
  command = "ffmpeg -y -i \"#{video_path}\" -s #{width}x#{height} -ss \"#{timestamp}\" -vframes 1 \"#{file}\" 2>&1 >/dev/null"
  # puts "COMMAND: #{command}"
  `#{command}`
  raise "Failed to grab screenshot at #{timestamp} from #{video_path} (using #{command})" unless $CHILD_STATUS.to_i == 0
  tmp
end

.md5digest(file_path) ⇒ String 



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 93

def md5digest(file_path)
  Digest::MD5.hexdigest(File.read(file_path))
end

.portrait?(path) ⇒ Boolean

Is the video or image in portrait mode ? Supports all video and images required by DU-UTC right now



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 52

def portrait?(path)
  resolution = resolution(path)
  resolution[0] < resolution[1]
end

.resolution(path) ⇒ Object

Identifies the resolution of a video or an image. Supports all video and images required by DU-UTC right now



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 43

def resolution(path)
  return FastImage.size(path) if content_type(path).start_with?("image")
  return video_resolution(path) if content_type(path).start_with?("video")
  raise "Cannot find resolution of file #{path}"
end

.video_resolution(video_path) ⇒ Array

identifies the resolution of a video using ‘ffmpeg`



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# File 'spaceship/lib/spaceship/du/utilities.rb', line 77

def video_resolution(video_path)
  command = "ffmpeg -i \"#{video_path}\" 2>&1"
  # puts "COMMAND: #{command}"
  output = `#{command}`
  # Note: ffmpeg exits with 1 if no output specified
  # raise "Failed to find video information from #{video_path} (using #{command})" unless $CHILD_STATUS.to_i == 0
  output = output.force_encoding("BINARY")
  video_infos = output.split("\n").select { |l| l =~ /Stream.*Video/ }
  raise "Unable to find Stream Video information from ffmpeg output of #{command}" if video_infos.count == 0
  video_info = video_infos[0]
  res = video_info.match(/.* ([0-9]+)x([0-9]+).*/)
  raise "Unable to parse resolution information from #{video_info}" if res.size < 3
  [res[1].to_i, res[2].to_i]
end