VTT opens and saves tagged text files in VTT file format. Two types of file format will be displayed (opened) in VTT:

• Pure text
• Correct VTT format

I. Text Content

• The original not-tagged text in UTF-8
• A line starts with # is ignored and used as a comment
• Separated header for Text Content:

  #<---------------------------------------------------------------------->
  #<Text Content>
  #<---------------------------------------------------------------------->
  ...
  

II. Tags Configuration

• Each line represents a Tag configuration used in VTT
• Each line must contain all 14 fields in the correct format and legal value
• A line starts with # is ignored and used as a comment
• The first tag is reserved (reserved tag) by VTT
  • It's name is pre-defined as Text/Clear
  • It's bold|Italic|Underline properties are used for clear markup
  • It's Display property is not used
  • It's foreground and background colors are used for the high-light color
• A tag id uniquely define by name and category in VTT
• Separated header and reserved (the 1st) tag for Tags Configuration:

  #<---------------------------------------------------------------------->
  #<Tags Configuration>
  #<Name|Category|Bold|Italic|Underline|Display|FR|FG|FB|BR|BG|BB|FontFamily|FontSize>
  #<---------------------------------------------------------------------->
  Text/Clear||false|false|false|true|255|255|255|0|51|153|Monospaced|12
  #<---------------------------------------------------------------------->
  ...
  

• Tag Fields Format:

  	Field 1	Field 2	Field 3	Field 4	Field 5	Field 6	Field 7	Field 8	Field 9	Field 10	Field 11	Field 12	Field 13	Field 14
  Description	Name	Category	Bold	Italic	Underline	Display	Foreground-Red	Foreground-Green	Foreground-Blue	Background-Red	Background-Green	Background-Blue	Font Family	Font size
  Java Type	String	String	boolean	boolean	boolean	boolean	int	int	int	int	int	int	String	String
  Example	Text/Clear		true false	true false	true false	true false	0 ~ 255	0 ~ 255	0 ~ 255	0 ~ 255	0 ~ 255	0 ~ 255	Dialog DialogInput Monospaced SansSerif Serif	8 10 12 14 ... +0 +2 -2

III. Markups Information

• Each line represents a Markup information used in VTT
• A line starts with # is ignored and used as a comment
• Each line must contain the correct format/data for Fields 1 ~ 5
  • Field 1 (Offset) & field 2 (Length): must be integer (< 2147483647)
  • The combination of field 3 (tag name) and field 4 (tag category): must exist from the tags list
  • field 5: Annotation can be empty
  • Spaces in the beginning and end are trimmed in Fields 1 ~ 5
• Fields 6 is the tagged text, which is used for NLP purposed and is ignored in VTT
• Fields 6+ are ignored in VTT and can be used for other NLP purposes. However, all data from fields 6+ can't be save or displayed.
• Character "|" is not allowed to used in the first 5 fields
• No two lines should have same offset and length (A word can only markuped with one tag)
• All lines are sorted by offset (smaller first) and then length (larger first)
• Separated header for markups information:

  #<---------------------------------------------------------------------->
  #<Markups Information>
  #<Offset|Length|TagName|TagCategory|Annotation|TagText>
  #<---------------------------------------------------------------------->
  ...
  

  	Field 1	Field 2	Field 3	Field 4	Field 5	Field 6	More Fields
  Description	Offset	Length	Tagged name	Tag Category	Annotation	Tagged Text	Other NLP fields
  Java Type	int	int	String	String	String	Not used	Not used