```ruby
require_relative 'box_path'
require_relative 'box_parsers/meta_box'
require_relative 'box_parsers/mvhd_box'

module FileData
  Mpeg4ValueInfo = Struct.new(:name, :parser_class, :method_name, :box_path)

  # Parses and returns metadata from an Mpeg4 file
  class Mpeg4

    class << self
      ['.mp4', '.mpeg4', '.m4v'].each { |e| FileInfo.info_maps[e] = Mpeg4 }

      values = [Mpeg4ValueInfo.new('origin_date', MetaBoxParser,
                                   'creation_date', %w[moov meta]),
                Mpeg4ValueInfo.new('creation_date', MvhdBoxParser,
                                   'creation_time', %w[moov mvhd])]

      values.each do |v|
        define_method(v.name) do |stream|
          get_value(stream, v.parser_class, v.method_name, *v.box_path)
        end
      end
    end

    def self.get_value(stream, parser, method, *box_path)
      box = BoxPath.get_root_path(stream, *box_path)
      parser.parse(box.content_stream).send(method) unless box.nil?
    end
  end
end
```

Simplify the method creation logic in Mpeg4.rb
user
```ruby
require_relative 'box_path'
require_relative 'box_parsers/meta_box'
require_relative 'box_parsers/mvhd_box'

module FileData
  Mpeg4ValueInfo = Struct.new(:name, :parser_class, :method_name, :box_path)

  # Parses and returns metadata from an Mpeg4 file
  class Mpeg4

    class << self
      ['.mp4', '.mpeg4', '.m4v'].each { |e| FileInfo.info_maps[e] = Mpeg4 }

      values = [['origin_date', MetaBoxParser,
                                   'creation_date', 'moov', 'meta'],
                ['creation_date', MvhdBoxParser,
                                   'creation_time', 'moov', 'mvhd']]

      values.each do |v|
        define_method(v[0]) do |stream|
          get_value(*v.drop(1).unshift(stream))
        end
      end
    end

    def self.get_value(stream, parser, method, *box_path)
      box = BoxPath.get_root_path(stream, *box_path)
      parser.parse(box.content_stream).send(method) unless box.nil?
    end
  end
end
```
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