§  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 § 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.
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   (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 Š, Œ, š, œ, Ÿ.

   (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 code 0×31 G0 single quote (‘), char code
   0×27
   Close single quote (’), G2 char code 0×32 G0 single quote ('), char
   code 0×27
   Open double quote (“), G2 char code 0×33 G0 double quote (“), char code
   0×22
   Close double quote (”), G2 char code 0×34 G0 double quote (”), char
   code 0×22
   Bold bullet (•), G2 char code 0×35 G1 bullet (•), char code 0×B7
   Elipsis (. . .), G2 char code 0×25 G0 underscore (_), char code 0×5F
   One-eighth ( 1/8), G2 char code 0×76 G0 percent sign (%), char code
   0×25
   Three-eighths ( 3/8), G2 char code 0×77 G0 percent sign (%), char code
   0×25
   Five-eighths ( 5/8), G2 char code 0×78 G0 percent sign (%), char code
   0×25
   Seven-eighths ( 7/8), G2 char code 0×79 G0 percent sign (%), char code
   0×25
   Vertical border (|), G2 char code 0×7A G0 stroke (|), char code 0×7C
   Upper-right border (⌉), G2 char code 0×7B G0 dash (-), char code 0×2D
   Lower-left border (⌊), G2 char code 0×7C G0 dash (-), char code 0×2D
   Horizontal border (―), G2 char code 0×7D G0 dash (-), char code 0×2D
   Lower-right border (⌋), G2 char code 0×7E G0 dash (-), char code 0×2D
   Upper-left border (⌈), G2 char code 0×7F G0 dash (-), char code 0×2D

   (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 Limits
   Screen aspect ratio Maximum anchor position resolution Minimum anchor
   position resolution Maximum displayed rows Maximum characters per row
   4:3 75v×160h 15v×32h 4 32
   16:9 75v×210h 15v×42h 4 42
   Other 75v×(5×H) 15v×H* 4 ^1

   ^1H = 32 × (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 a1/5reduction 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.

   Table 4—Predefined Window Style ID's
   Style ID # Justify Print direction Scroll
   direction Word wrap Display
   effect Effect
   direction Effect
   speed Fill color Fill opacity Border type Border color Usage
   1 Left Left-to-right Bottom-to-top No Snap n/a n/a (0,0,0) Black Solid
   None n/a NTSC Style 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) Black Solid
   None n/a NTSC Style Centered PopUp Captions
   4 Left Left-to-right Bottom-to-top Yes Snap n/a n/a (0,0,0) Black Solid
   None n/a NTSC Style 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) Black Solid
   None n/a NTSC Style Centered RollUp Captions
   7 Left Top-to-bottom Right-to-left No Snap n/a n/a (0,0,0) Black Solid
   None n/a Ticker Tape

   Table 5—Predefined Pen Style ID's
   Predefined style ID Pen size Font style Offset Italics Underline Edge
   type Foregrnd color Foregrnd opacity Backgrnd color Backgrnd opacity
   Edge color Usage
   1 Stndr 0 Normal No No None (2,2,2) White Solid (0,0,0) Black Solid n/a
   Default NTSC Style*
   2 Stndr 1 Normal No No None (2,2,2) Solid (0,0,0) White Solid n/a NTSC
   Style* Mono w/Serif
   3 Stndr 2 Normal No No None (2,2,2) White Solid (0,0,0) Black Solid n/a
   NTSC Style* Prop w/ Serif
   4 Stndr 3 Normal No No None (2,2,2) White Solid (0,0,0) Black Solid n/a
   NTSC Style* Mono w/o Serif
   5 Stndr 4 Normal No No None (2,2,2) White Solid (0,0,0) Black Solid n/a
   NTSC Style* Prop w/o Serif
   6 Stndr 3 Normal No No Unifrm (2,2,2) White Solid n/a Transparent
   (0,0,0) Black Mono w/o Serif, Bordered Text, No BG
   7 Stndr 4 Normal No No Unifrm (2,2,2) White Solid n/a Transparent
   (0,0,0) Black Prop. w/o 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 than1/15of the height of the
   safe-title area, and the width of the widest character is no wider
   than1/32of the width of the safe-title area for 4:3 displays and1/42of
   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 than1/32of 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]