old_contents: 
  # to be added to...
  PRONOM = {
      "JP2 (JPEG 2000 part 1)": "x-fmt/392",
      "MPEG-2 Video Format": "x-fmt/386"
  }
  
  # map of tessella names to premis names
  # also, presence in here means we want it in new version
  SIGNIFICANT_PROPS = {
      "Image Width": "ImageWidth",
      "Image Height": "ImageHeight",
      "Bitrate (kbps)": "Bitrate",
      "Length In Seconds": "Duration",
  }
  
new_contents: 
  # to be added to...
  # bagger will throw an exception if the format in METS is not a key in this dictionary.
  PRONOM = {
      "JP2 (JPEG 2000 part 1)": "x-fmt/392",
      "MPEG-2 Video Format": "x-fmt/386",
      "Acrobat PDF 1.4 - Portable Document Format 1.4": "fmt/18"
  }
  
  # map of tessella names to premis names
  # also, presence in here means we want it in new version
  SIGNIFICANT_PROPS = {
      "Image Width": "ImageWidth",
      "Image Height": "ImageHeight",
      "Bitrate (kbps)": "Bitrate",
      "Length In Seconds": "Duration",
      "Number of Pages": "PageNumber"  # this is a property of PDFs
  }
  
  # Ignored properties observed so far:
  
  # "Creation Date"
  # "Number of Images"
  # "Bits Per Sample"
  # "Samples Per Pixel"
  
subject: archive bagit mappings for PDFs