Sec.  15.122   Closed caption decoder requirements for digital television
receivers and converter boxes.

   

   (a)(1) Effective July 1, 2002, all digital television receivers with
   picture screens in the 4:3 aspect ratio with picture screens measuring
   13 inches or larger diagonally, all digital television receivers with
   picture screens in the 16:9 aspect ratio measuring 7.8 inches or
   larger vertically and all separately sold DTV tuners shipped in
   interstate commerce or manufactured in the United States shall comply
   with the provisions of this section.

   Note to paragraph (a)(1): This paragraph places no restrictions on the
   shipping or sale of digital television receivers that were
   manufactured before July 1, 2002.

   (2) Effective July 1, 2002, DTV converter boxes that allow digitally
   transmitted television signals to be displayed on analog receivers
   shall pass available analog caption information to the attached
   receiver in a form recognizable by that receiver's built-in caption
   decoder circuitry.

   Note to paragraph (a)(2): This paragraph places no restrictions on the
   shipping or sale of DTV converter boxes that were manufactured before
   July 1, 2002.

   (b) Digital television receivers and tuners must be capable of
   decoding closed captioning information that is delivered pursuant to
   EIA-708-B: "Digital Television (DTV) Closed Captioning" (incorporated
   by reference, see Sec. 15.38).

   (c) Services. (1) Decoders must be capable of decoding and processing
   data for the six standard services, Caption Service #1 through Caption
   Service #6.

   (2) Decoders that rely on Program and System Information Protocol data
   to implement closed captioning functions must be capable of decoding
   and processing the Caption Service Directory data. Such decoders must
   be capable of decoding all Caption Channel Block Headers consisting of
   Standard Service Headers, Extended Service Block Headers, and Null
   Block headers. However, decoding of the data is required only for
   Standard Service Blocks (Service IDs <-6), and then only if the
   characters for the corresponding language are supported. The decoders
   must be able to display the directory for services 1 through 6.

   (d) Code space organization. (1) Decoders must support Code Space C0,
   G0, C1, and G1 in their entirety.
   [er29se00.000.gif]

   View or download PDF

   (2) The following characters within code space G2 must be supported:

   (i) Transparent space ([TSP]).

   (ii) Non-breaking transparent space ([NBTSP]).

   (iii) Solid block ( ).

   (iv) Trademark symbol ( TM ).

   (v) Latin-1 characters S, OE, s, oe, Y.

   (3) The substitutions in Table 2 are to be made if a decoder does not
   support the remaining G2 characters.

                 Table 2_G2 Character Substitution Table
------------------------------------------------------------------------
           G2 Character                       Substitute with
------------------------------------------------------------------------
Open single quote (`), G2 char     G0 single quote (`), char code 0x27
 code 0x31.
Close single quote ('), G2 char    G0 single quote ('), char code 0x27
 code 0x32.
Open double quote (``), G2 char    G0 double quote (``), char code 0x22
 code 0x33.
Close double quote (''), G2 char   G0 double quote (''), char code 0x22
 code 0x34.
Bold bullet ( o ), G2 char     G1 bullet ( o ), char code 0xB7
 code 0x35.
Elipsis (. . .), G2 char code      G0 underscore (_), char code 0x5F
 0x25.
One-eighth (\1/8\), G2 char code   G0 percent sign (%), char code 0x25
 0x76.
Three-eighths (\3/8\), G2 char     G0 percent sign (%), char code 0x25
 code 0x77.
Five-eighths (\5/8\), G2 char      G0 percent sign (%), char code 0x25
 code 0x78.
Seven-eighths (\7/8\), G2 char     G0 percent sign (%), char code 0x25
 code 0x79.
Vertical border ([verbar]), G2     G0 stroke ([verbar]), char code 0x7C
 char code 0x7A.
Upper-right border ([rceil]), G2   G0 dash (-), char code 0x2D
 char code 0x7B.
Lower-left border ([lfloor]), G2   G0 dash (-), char code 0x2D
 char code 0x7C.
Horizontal border ([horbar]), G2   G0 dash (-), char code 0x2D
 char code 0x7D.
Lower-right border ([rfloor]), G2  G0 dash (-), char code 0x2D
 char code 0x7E.
Upper-left border ([lceil]), G2    G0 dash (-), char code 0x2D
 char code 0x7F.
------------------------------------------------------------------------

   (4) Support for code spaces C2, C3, and G3 is optional. All
   unsupported graphic symbols in the G3 code space are to be substituted
   with the G0 underscore character (_), char code 0×5F.

   (e) Screen coordinates. Table 3 specifies the screen coordinate
   resolutions and limits for anchor point positioning in 4:3 and 16:9
   display formats, and the number of characters per row.

                                Table 3_Screen Coordinate Resolutions and Limit
s
-------------------------------------------------------------------------------
---------------------------------

            Maximum     Maximum
     Screen aspect ratio         Maximum anchor position      Minimum anchor po
sition     displayed   characters
                                        resolution                   resolution
             rows       per row
-------------------------------------------------------------------------------
---------------------------------
4:3..........................  75vx160h...................  15vx32h............
........           4           32
16:9.........................  75vx210h...................  15vx42h............
........           4           42
Other........................  75vx(5xH)..................  15vxH*.............
........           4          \1\
-------------------------------------------------------------------------------
---------------------------------
\1\H = 32 x (the width of the screen in relation to a 4:3 display). For example
, the 16:9 format is \1/3\ wider
  than a 4:3 display; thus, H = 32 * \4/3\ = 42.667, or 42.

   (1) This means that the minimum grid resolution for a 4:3 aspect ratio
   instrument is 15 vertical positions × 32 horizontal positions. This
   minimum grid resolution for 16:9 ratio instrument is 15 vertical
   positions × 42 horizontal positions. These minimum grid sizes are to
   cover the entire safe-title area of the corresponding screen.

   (2) The minimum coordinates equate to a 1/5 reduction in the maximum
   horizontal and vertical grid resolution coordinates. Caption providers
   are to use the maximum coordinate system values when specifying anchor
   point positions. Decoders using the minimum resolution are to divide
   the provided horizontal and vertical screen coordinates by 5 to derive
   the equivalent minimum coordinates.

   (3) Any caption targeted for both 4:3 and 16:9 instruments is limited
   to 32 contiguous characters per row. If a caption is received by a 4:3
   instrument that is targeted for a 16:9 display only, or requires a
   window width greater than 32 characters, then the caption may be
   completely disregarded by the decoder. 16:9 instruments should be able
   to process and display captions intended for 4:3 displays, providing
   all other minimum recommendations are met.

   (4) If the resulting size of any window is larger than the safe title
   area for the corresponding display's aspect ratio, then this window
   will be completely disregarded.

   (f) Caption windows. (1) Decoders need to display no more than 4 rows
   of captions on the screen at any given time, regardless of the number
   of windows displayed. This implies that no more than 4 windows can be
   displayed at any given time (with each having only one caption row).
   However, decoders should maintain storage to support a minimum total
   of 8 rows of captions. This storage is needed for the worst-case
   support of a displayed window with 4 rows of captioning and a
   non-displayed window which is buffering the incoming rows for the next
   4-row caption. As implied above, the maximum number of windows that
   may be displayed at any one time by a minimum decoder implementation
   is 4. If more than 4 windows are defined in the caption stream, the
   decoder may disregard the youngest and lowest priority window
   definition(s). Caption providers must be aware of this limitation, and
   either restrict the total number of windows used or accept that some
   windows will not be displayed.

   (2) Decoders do not need to support overlapped windows. If a window
   overlaps another window, the overlapped window need not be displayed
   by the decoder.

   (3) At a minimum, decoders will assume that all windows have rows and
   columns "locked". This implies that if a decoder implements the SMALL
   pen-size, then word-"un"wrapping, when shrinking captions, need not be
   implemented. Also, if a decoder implements the LARGE pen size, then
   word wrapping (when enlarging captions) need not be implemented.

   (4) Whenever possible, the receiver should render embedded carriage
   returns as line breaks, since these carriage returns indicate an
   important aspect of the caption's formatting as determined by the
   service provider. However, it may sometimes be necessary for the
   receiver to ignore embedded line breaks. For example, if a caption is
   to appear in a larger font, and if its window's rows and/or columns
   are unlocked, the rows of text may need to become longer or shorter to
   fit within the allocated space. Such automatic reformatting of a
   caption is known as "word wrap." If decoders support word-wrapping, it
   must be implemented as follows:

   (i) The receiver should follow standard typographic practice when
   implementing word wrap. Potential breaking points (word-wrapping
   points) are indicated by the space character (20h) and by the hyphen
   character (2Dh).

   (ii) If a row is to be broken at a space, the receiver should remove
   the space from the caption display. If a row is to be broken after a
   hyphen, the hyphen should be retained.

   (iii) If an embedded return is to be removed, it should usually be
   replaced with a space. However, if the character to the left of the
   embedded return is a hyphen, the embedded return should be removed but
   NOT replaced with a space.

   (iv) This specification does not include optional hyphens, nor does it
   provide for any form of automatic hyphenation. No non-breaking hyphen
   is defined. The non-breaking space (A0h in the G1 code set) and the
   non-breaking transparent space (21h in the G2 code set) should not be
   considered as potential line breaks.

   (v) If a single word exceeds the length of a row, the word should be
   placed at the start of a new row, broken at the character following
   the last character that fits on the row, and continued with further
   breaks if needed.

   (g) Window text painting. (1) All decoders should implement "left",
   "right", and "center" caption-text justification. Implementation of
   "full" justification is optional. If "full" justification is not
   implemented, fully justified captions should be treated as though they
   are "left" justified.

   (i) For "left" justification, decoders should display any portion of a
   received row of text when it is received. For "center", "right", and
   "full" justification, decoders may display any portion of a received
   row of text when it is received, or may delay display of a received
   row of text until reception of a row completion indicator. A row
   completion indicator is defined as receipt of a CR, ETX or any other
   command, except SetPenColor, SetPenAttributes, or SetPenLocation where
   the pen relocation is within the same row.

   (ii) Receipt of a character for a displayed row which already contains
   text with "center", "right" or "full" justification will cause the row
   to be cleared prior to the display of the newly received character and
   any subsequent characters. Receipt of a justification command which
   changes the last received justification for a given window will cause
   the window to be cleared.

   (2) At a minimum, decoders must support LEFT_TO_RIGHT printing.

   (3) At a minimum, decoders must support BOTTOM_TO_TOP scrolling. For
   windows sharing the same horizontal scan lines on the display,
   scrolling may be disabled.

   (4) At a minimum, decoders must support the same recommended practices
   for scroll rate as is provided for NTSC closed-captioning.

   (5) At a minimum, decoders must support the same recommended practices
   for smooth scrolling as is provided for NTSC closed-captioning.

   (6) At a minimum, decoders must implement the "snap" window display
   effect. If the window "fade" and "wipe" effects are not implemented,
   then the decoder will "snap" all windows when they are to be
   displayed, and the "effect speed" parameter is ignored.

   (h) Window colors and borders. At a minimum, decoders must implement
   borderless windows with solid, black backgrounds (i.e., border type =
   NONE, fill color = (0,0,0), fill opacity = SOLID), and borderless
   transparent windows (i.e., border type = NONE, fill opacity =
   TRANSPARENT).

   (i) Predefined window and pen styles. Predefined Window Style and Pen
   Style ID's may be provided in the DefineWindow command. At a minimum,
   decoders should implement Predefined Window Attribute Style 1 and
   Predefined Pen Attribute Style 1, as shown in Table 4 and Table 5,
   respectively.

                                                                              T
able 4_Predefined Window Style ID's
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------
                                                 Print          Scroll       Wo
rd      Display       Effect        Effect                      Fill
          Border
          Style ID #              Justify      direction      direction      wr
ap      effect       direction      speed      Fill color     opacity    Border
 type     color          Usage
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------
1............................  Left........  Left-to-right  Bottom-to-top  No..
...  Snap........  n/a.........  n/a........  (0,0,0)       Solid......  None..
.....  n/a........  NTSC Style

                                               Black.
                     PopUp


                     Captions
2............................  Left........  Left-to-right  Bottom-to-top  No..
...  Snap........  n/a.........  n/a........  n/a.........  Transparent  None..
.....  n/a........  PopUp Captions


                     w/o Black


                     Background
3............................  Cntr........  Left-to-right  Bottom-to-top  No..
...  Snap........  n/a.........  n/a........  (0,0,0)       Solid......  None..
.....  n/a........  NTSC Style

                                               Black.
                     Centered


                     PopUp


                     Captions
4............................  Left........  Left-to-right  Bottom-to-top  Yes.
...  Snap........  n/a.........  n/a........  (0,0,0)       Solid......  None..
.....  n/a........  NTSC Style

                                               Black.
                     RollUp


                     Captions
5............................  Left........  Left-to-right  Bottom-to-top  Yes.
...  Snap........  n/a.........  n/a........  n/a.........  Transparent  None..
.....  n/a........  RollUp


                     Captions w/o


                     Black


                     Background
6............................  Cntr........  Left-to-right  Bottom-to-top  Yes.
...  Snap........  n/a.........  n/a........  (0,0,0)       Solid......  None..
.....  n/a........  NTSC Style

                                               Black.
                     Centered


                     RollUp


                     Captions
7............................  Left........  Top-to-bottom  Right-to-left  No..
...  Snap........  n/a.........  n/a........  (0,0,0)       Solid......  None..
.....  n/a........  Ticker Tape

                                               Black.
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------


 Table 5_Predefined Pen Style ID's
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------

                                      Foregrnd     Foregrnd     Backgrnd     Ba
ckgrnd
      Predefined style ID          Pen size      Font style       Offset      I
talics     Underline    Edge type      color       opacity       color       op
acity     Edge color      Usage
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------
1.............................  Stndr........  0............  Normal.......  No
.......  No..........  None.......  (2,2,2)      Solid......  (0,0,0)      Soli
d......  n/a........  Default NTSC

                                     White.                    Black.
                       Style*
2.............................  Stndr........  1............  Normal.......  No
.......  No..........  None.......  (2,2,2)....  Solid......  (0,0,0)      Soli
d......  n/a........  NTSC Style*

                                                               White.
                       Mono w/


                       Serif
3.............................  Stndr........  2............  Normal.......  No
.......  No..........  None.......  (2,2,2)      Solid......  (0,0,0)      Soli
d......  n/a........  NTSC Style*

                                     White.                    Black.
                       Prop w/


                       Serif
4.............................  Stndr........  3............  Normal.......  No
.......  No..........  None.......  (2,2,2)      Solid......  (0,0,0)      Soli
d......  n/a........  NTSC Style*

                                     White.                    Black.
                       Mono w/o


                       Serif
5.............................  Stndr........  4............  Normal.......  No
.......  No..........  None.......  (2,2,2)      Solid......  (0,0,0)      Soli
d......  n/a........  NTSC Style*

                                     White.                    Black.
                       Prop w/o


                       Serif
6.............................  Stndr........  3............  Normal.......  No
.......  No..........  Unifrm.....  (2,2,2)      Solid......  n/a........  Tran
sparent  (0,0,0)      Mono w/o

                                     White.
          Black.       Serif,


                       Bordered


                       Text, No BG
7.............................  Stndr........  4............  Normal.......  No
.......  No..........  Unifrm.....  (2,2,2)      Solid......  n/a........  Tran
sparent  (0,0,0)      Prop. w/o

                                     White.
          Black.       Serif,


                       Bordered


                       Text, No BG

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
----------------------------------
*``NTSC Style''_White Text on Black Background

   (j) Pen size. (1) Decoders must support the standard, large, and small
   pen sizes and must allow the caption provider to choose a pen size and
   allow the viewer to choose an alternative size. The STANDARD pen size
   should be implemented such that the height of the tallest character in
   any implemented font is no taller than 1/15 of the height of the
   safe-title area, and the width of the widest character is no wider
   than 1/32 of the width of the safe-title area for 4:3 displays and
   1/42 of the safe-title area width for 16:9 displays.

   (2) The LARGE pen size should be implemented such that the width of
   the widest character in any implemented font is no wider than 1/32 of
   the safe-title area for 16:9 displays. This recommendation allows for
   captions to grow to a LARGE pen size without having to reformat the
   caption since no caption will have more than 32 characters per row.

   (k) Font styles. (1) Decoders must support the eight fonts listed
   below. Caption providers may specify 1 of these 8 font styles to be
   used to write caption text. The styles specified in the "font style"
   parameter of the SetPenAttributes command are numbered from 0 through
   7. The following is a list of the 8 required font styles. For
   information purposes only, each font style references one or more
   popular fonts which embody the characteristics of the style:

   (i) 0--Default (undefined)

   (ii) 1--Monospaced with serifs (similar to Courier)

   (iii) 2--Proportionally spaced with serifs (similar to Times New
   Roman)

   (iv) 3--Monospaced without serifs (similar to Helvetica Monospaced)

   (v) 4--Proportionally spaced without serifs (similar to Arial and
   Swiss)

   (vi) 5--Casual font type (similar to Dom and Impress)

   (vii) 6--Cursive font type (similar to Coronet and Marigold)

   (viii) 7--Small capitals (similar to Engravers Gothic)

   (2) Font styles may be implemented in any typeface which the decoder
   manufacturer deems to be a readable rendition of the font style, and
   need not be in the exact typefaces given in the example above.
   Decoders must include the ability for consumers to choose among the
   eight fonts. The decoder must display the font chosen by the caption
   provider unless the viewer chooses a different font.

   (l) Character offsetting. Decoders need not implement the character
   offsetting (i.e., subscript and superscript) pen attributes.

   (m) Pen styles. At a minimum, decoders must implement normal, italic,
   and underline pen styles.

   (n) Foreground color and opacity. (1) At a minimum, decoders must
   implement transparent, translucent, solid and flashing character
   foreground type attributes.

   (2) At a minimum, decoders must implement the following character
   foreground colors: white, black, red, green, blue, yellow, magenta and
   cyan.

   (3) Caption providers may specify the color/opacity. Decoders must
   include the ability for consumers to choose among the color/opacity
   options. The decoder must display the color/opacity chosen by the
   caption provider unless the viewer chooses otherwise.

   (o) Background color and opacity. (1) Decoders must implement the
   following background colors: white, black, red, green, blue, yellow,
   magenta and cyan. It is recommended that this background is extended
   beyond the character foreground to a degree that the foreground is
   separated from the underlying video by a sufficient number of
   background pixels to insure the foreground is separated from the
   background.

   (2) Decoders must implement transparent, translucent, solid and
   flashing background type attributes. Caption providers may specify the
   color/opacity. Decoders must include the ability for consumers to
   choose among the color/opacity options. The decoder must display the
   color/opacity chosen by the caption provider unless the viewer chooses
   otherwise.

   (p) Character edges. Decoders must implement separate edge color and
   type attribute control.

   (q) Color representation. (1) At a minimum, decoders must support the
   8 colors listed in Table 6.

                    Table 6_Minimum Color List Table
------------------------------------------------------------------------
                    Color                        Red     Green     Blue
------------------------------------------------------------------------
Black........................................        0        0        0
White........................................        2        2        2
Red..........................................        2        0        0
Green........................................        0        2        0
Blue.........................................        0        0        2
Yellow.......................................        2        2        0
Magenta......................................        2        0        2
Cyan.........................................        0        2        2
------------------------------------------------------------------------

   (2)(i) When a decoder supporting this Minimum Color List receives an
   RGB value not in the list, it will map the received value to one of
   the values in the list via the following algorithm:

   (A) All one (1) values are to be changed to 0.

   (B) All two (2) values are to remain unchanged.

   (C) All three (3) values are to be changed to 2.

   (ii) For example, the RGB value (1,2,3) will be mapped to (0,2,2),
   (3,3,3) will be mapped to (2,2,2) and (1,1,1) will be mapped to
   (0,0,0).

   (3) Table 7 is an alternative minimum color list table supporting 22
   colors.

              Table 7_Alternative Minimum Color List Table
------------------------------------------------------------------------
                    Color                        Red     Green     Blue
------------------------------------------------------------------------
Black........................................        0        0        0
Gray.........................................        1        1        1
White........................................        2        2        2
Bright White.................................        3        3        3
Dark Red.....................................        1        0        0
Red..........................................        2        0        0
Bright Red...................................        3        0        0
Dark Green...................................        0        1        0
Green........................................        0        2        0
Bright Green.................................        0        3        0
Dark Blue....................................        0        0        1
Blue.........................................        0        0        2
Bright Blue..................................        0        0        3
Dark Yellow..................................        1        1        0
Yellow.......................................        2        2        0
Bright Yellow................................        3        3        0
Dark Magenta.................................        1        0        1
Magenta......................................        2        0        2
Bright Magenta...............................        3        0        3
Dark Cyan....................................        0        1        1
Cyan.........................................        0        2        2
Bright Cyan..................................        0        3        3
------------------------------------------------------------------------

   (i) When a decoder supporting the Alternative Minimum Color List in
   Table 7 receives an RGB value not in the list (i.e., an RGB value
   whose non-zero elements are not the same value), it will map the
   received value to one of the values in the list via the following
   algorithm:

   (A) For RGB values with all elements non-zero and different--e.g.,
   (1,2,3), (3,2,1), and (2,1,3), the 1 value will be changed to 0, the 2
   value will remain unchanged, and the 3 value will be changed to 2.

   (B) For RGB values with all elements non-zero and with two common
   elements--e.g. (3,1,3), (2,1,2), and (2,2,3), if the common elements
   are 3 and the uncommon one is 1, then the 1 elements is changed to 0;
   e.g. (3,1,3) -> (3,0,3). If the common elements are 1 and the uncommon
   element is 3, then the 1 elements are changed to 0, and the 3 element
   is changed to 2; e.g. (1,3,1) -> (0,2,0). In all other cases, the
   uncommon element is changed to the common value; e.g., (2,2,3) ->
   (2,2,2), (1,2,1) -> (1,1,1), and (3,2,3) -> (3,3,3).

   (ii) All decoders not supporting either one of the two color lists
   described above, must support the full 64 possible RGB color value
   combinations.

   (r) Character rendition considerations. In NTSC Closed Captioning,
   decoders were required to insert leading and trailing spaces on each
   caption row. There were two reasons for this requirement:

   (1) To provide a buffer so that the first and last characters of a
   caption row do not fall outside the safe title area, and

   (2) To provide a black border on each side of a character so that the
   "white" leading pixels of the first character on a row and the
   trailing "white" pixels of the last character on a row do not bleed
   into the underlying video.

   (i) Since caption windows are required to reside in the safe title
   area of the DTV screen, reason 1 (above) is not applicable to DTVCC
   captions.

   (ii) The attributes available in the SetPenAttributes command for
   character rendition (e.g., character background and edge attributes)
   provide unlimited flexibility to the caption provider when describing
   caption text in an ideal decoder implementation. However,
   manufacturers need not implement all pen attributes. Thus it is
   recommended that no matter what the level of implementation, decoder
   manufacturers should take into account the readability of all caption
   text against a variety of all video backgrounds, and should implement
   some automatic character delineation when the individual control of
   character foreground, background and edge is not supported.

   (s) Service synchronization. Service Input Buffers must be at least
   128 bytes in size. Caption providers must keep this lower limit in
   mind when following Delay commands with other commands and window
   text. In other words, no more than 128 bytes of DTVCC commands and
   text should be transmitted (encoded) before a pending Delay command's
   delay interval expires.

   (t) Settings. Decoders must include an option that permits a viewer to
   choose a setting that will display captions as intended by the caption
   provider (a default). Decoders must also include an option that allows
   a viewer's chosen settings to remain until the viewer chooses to alter
   these settings, including periods when the television is turned off.

   [ 65 FR 58471 , Sept. 29, 2000, as amended at  69 FR 2849 , Jan. 21, 2004]