Method and/or apparatus for color space reduction for transcoding subpicture elements
An apparatus including a first circuit, a second circuit and a third circuit. The first circuit may be configured to collect color statistics. The second circuit may be configured to sort colors based upon the color statistics collected by the first circuit. The third circuit may be configured to generate a mapping function between the sorted colors and a color space of a receiving standard.
1. An apparatus comprising:
a first circuit configured to collect color statistics;
a second circuit configured to sort colors based upon the color statistics collected by the first circuit; and
a third circuit configured to generate a mapping function between the sorted colors and a color space of a receiving standard, wherein said mapping function is generated such that a distance between each sorted color and a corresponding reference color is minimized.
2. The apparatus according to claim 1 , wherein said color statistics are weighted.
3. The apparatus according to claim 1 , wherein said first circuit is configured to collect said color statistics during decoding of an input signal.
4. The apparatus according to claim 3 , wherein the input signal comprises a digital video broadcast (DVB) compliant subtitle or a Teletext compliant subtitle.
5. The apparatus according to claim 1 , wherein said first circuit is further configured to generate a global color table.
6. The apparatus according to claim 5 , wherein said second circuit is further configured to reduce a number of colors in said global color table.
7. The apparatus according to claim 1 , wherein said apparatus is configured to convert a digital video broadcast (DVB) compliant subtitle to a digital versatile disc video recording (DVD-VR) compliant subpicture.
8. The apparatus according to claim 1 , further comprising a Digital Video Broadcast (DVB) compliant color mapping system configured to generate said color statistics.
9. The apparatus according to claim 1 , wherein said second circuit is further configured to restrict a number of sorted colors to grayscale colors when a number of available destination colors is not greater than a predefined percentage of the number of pixels in a source overlay.
10. The apparatus according to claim 1 , wherein said first circuit comprises:
a first decoder configured to generate statistics for a first number of colors;
a second decoder configured to generate statistics for a second number of colors, where said second number is greater than said first number; and
a third decoder configured to generate statistics for a third number of colors, where said third number is greater than said second number.
11. The apparatus according to claim 5 , wherein said global color table is generated based on a plurality of digital video broadcast (DVB) compliant subtitle regions.
12. The apparatus according to claim 6 , wherein said number of colors in said global color table is reduced based on a digital versatile disc video recording (DVD-VR) compliant subpicture color palette.
13. An apparatus comprising:
means for collecting weighted color statistics;
means for sorting colors based upon the weighted color statistics collected; and
means for generating a mapping function between the sorted colors and a color space of a receiving standard, wherein said mapping function is generated such that a distance between each sorted color and a corresponding reference color is minimized.
14. A method of color space reduction comprising the steps of:
collecting color statistics from an input signal using a decoder;
sorting colors based upon the color statistics collected; and
generating a mapping function between the sorted colors and a color space of a receiving standard, wherein said mapping function is generated by associating a reference color with each sorted color such that a distance between each sorted color and the associated reference color is minimized.
15. The method according to claim 14 , wherein said color statistics comprise weighted color statistics.
16. The method according to claim 14 , wherein said color statistics are collected during decoding of the input signal.
17. The method according to claim 16 , wherein the input signal comprises a digital video broadcast (DVB) compliant subtitle or a Teletext compliant subtitle.
18. The method according to claim 14 , further comprising:
generating a global color table for the input signal.
19. The method according to claim 18 , further comprising:
combining two or more subtitle regions of a source overlay to form a single destination overlay.
20. The method according to claim 18 , further comprising:
reducing a number of colors in said global color table.
21. The method according to claim 20 , further comprising:
assigning transparent colors an index of zero.
22. The method according to claim 14 , further comprising:
restricting a number of sorted colors to grayscale colors when a number of available destination colors is not greater than a predefined percentage of the number of pixels in a source overlay.
23. The method according to claim 18 , wherein said global color table is generated based on a plurality of digital video broadcast (DVB) compliant subtitle regions.
24. The method according to claim 20 , wherein the number of colors in said global color table is reduced based on a digital versatile disc video recording (DVD-VR) compliant subpicture color palette.