Class: FormatParser::MP4Parser

Inherits:
Object
  • Object
show all
Includes:
IOUtils, ISOBaseMediaFileFormat, ISOBaseMediaFileFormat::Utils
Defined in:
lib/parsers/mp4_parser.rb

Constant Summary collapse

MAGIC_BYTES = 
/^ftyp(iso[m2]|mp4[12]|m4[abprv] )$/i
BRAND_FORMATS = 
{
  'isom' => :mp4, # Prohibited as a major brand by ISO/IEC 14496-12 sec 6.3 paragraph 2, but occasionally used.
  'iso2' => :mp4, # Prohibited as a major brand by ISO/IEC 14496-12 sec 6.3 paragraph 2, but occasionally used.
  'mp41' => :mp4,
  'mp42' => :mp4,
  'm4a ' => :m4a,
  'm4b ' => :m4b, # iTunes audiobooks
  'm4p ' => :m4p, # iTunes audio
  'm4r ' => :m4r, # iTunes ringtones
  'm4v ' => :m4v, # iTunes video
}
AUDIO_FORMATS =

iTunes video

Set[:m4a, :m4b, :m4p, :m4r]
VIDEO_FORMATS = 
Set[:mp4, :m4v]
AUDIO_MIMETYPE = 
'audio/mp4'
VIDEO_MIMETYPE = 
'video/mp4'

Constants included from ISOBaseMediaFileFormat::Utils

ISOBaseMediaFileFormat::Utils::IDENTITY_MATRIX

Constants included from IOUtils

IOUtils::INTEGER_DIRECTIVES

Instance Method Summary collapse

Methods included from ISOBaseMediaFileFormat::Utils

#dimensions, #duration, #frame_rate, #video_codecs

Methods included from IOUtils

#read_bytes, #read_fixed_point, #read_int, #safe_read, #safe_skip, #skip_bytes

Instance Method Details

#call(io) ⇒ Object 



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# File 'lib/parsers/mp4_parser.rb', line 31

def call(io)
  @buf = FormatParser::IOConstraint.new(io)

  return unless matches_mp4_definition?

  box_tree = Measurometer.instrument('format_parser.mp4_parser.decoder.build_box_tree') do
    Decoder.new.build_box_tree(0xffffffff, @buf)
  end

  case file_format = file_format(box_tree)
  when VIDEO_FORMATS
    width, height = dimensions(box_tree)
    FormatParser::Video.new(
      codecs: video_codecs(box_tree),
      content_type: VIDEO_MIMETYPE,
      format: file_format,
      frame_rate: frame_rate(box_tree),
      height_px: height,
      intrinsics: box_tree,
      media_duration_seconds: duration(box_tree),
      width_px: width,
    )
  when AUDIO_FORMATS
    FormatParser::Audio.new(
      content_type: AUDIO_MIMETYPE,
      format: file_format,
      intrinsics: box_tree,
      media_duration_seconds: duration(box_tree),
    )
  else
    nil
  end
end

#likely_match?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parsers/mp4_parser.rb', line 27

def likely_match?(filename)
  /\.(mp4|m4[abprv])$/i.match?(filename)
end