Television – Basic receiver with additional function – For display of additional information
Reexamination Certificate
1999-03-23
2001-01-16
Hsia, Sherrie (Department: 2714)
Television
Basic receiver with additional function
For display of additional information
C348S589000, C348S600000
Reexamination Certificate
active
06175388
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for generating On-Screen-Display (OSD) messages. More particularly, this invention relates to a method and apparatus that reduces the memory bandwidth requirements of a decoding/displaying system by using one-bit pixels to access a palette that is pre-defined for an OSD region.
BACKGROUND OF THE INVENTION
On-Screen-Display messages play an important role in consumer electronics products by providing users with interactive information such as menus to guide them through the usage and configuration of the product. Other important features of OSD include the ability to provide Closed Captioning and the display of channel logos.
However, the heightened standard of digital video technology presents an ever increasing problem of generating and displaying OSD messages. For example, there are specific High Definition Television (HDTV) requirements that an HDTV must display up to 216 characters in four (4) “windows” versus the current National Television Systems Committee (NTSC) requirements of a maximum of 128 characters in one “window”. These new requirements place severe strains on the decoding/displaying system for television signals, which must decode the incoming encoded data streams and present the decoded data to a display system with minimal delays. Since OSD messages must be displayed (overlaid) with the video data, the microprocessor of the decoding/displaying system must assign a portion of the memory bandwidth to perform OSD functions, thereby increasing the memory bandwidth requirements of a decoding/displaying system and the overall computational overhead.
Thus, a need exists for a method and apparatus for generating On-Screen-Display (OSD) messages without increasing the hardware requirements, e.g., memory bandwidth, of a decoding/displaying system.
SUMMARY OF THE INVENTION
The invention concerns an apparatus and concomitant method for generating OSD messages by constructing a valid OSD bitstream having a
40
plurality of “one-bit” pixels.
More specifically, in accordance with the invention, an OSD unit retrieves an OSD bitstream from a storage device. The OSD bitstream contains an OSD header and OSD data. The OSD header contains control information that is used to program a color palette of the OSD unit and to provide instructions as to the treatment of the OSD data. The control information is programmed by a processor of a decoding/displaying system. If the “Compressed Pixel Mode” is enabled in the OSD header, then the OSD unit will treat each bit of the OSD data in the OSD bitstream as a “one-bit” pixel. Namely, each OSD data bit represents one of two possible indices, where each index identifies one of the many possible OSD palette entries. For example, if there are 16 possible entries which are accessible by 4-bit addresses, then the “one-bit” pixel can access two of the possible entries using only a single bit.
These and other aspects of the invention will be described with respect to the accompanying drawings.
REFERENCES:
patent: 0707426 (1996-04-01), None
patent: 2292294 (1996-02-01), None
patent: 94/29840 (1994-12-01), None
patent: 95/35626 (1995-12-01), None
Dinwiddie Aaron Hal
Knox Michael Dwayne
Hsia Sherrie
Kiel Paul P.
Thomson Licensing S.A.
Tripoli Joseph S.
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