WO1996038007B1 - Apparatus and method for generating on-screen-display messages using stored bitstreams - Google Patents

Abstract

An apparatus and concomitant method for constructing a valid OSD message bitstream from a plurality of stored character bitstreams. Each character of the OSD font set is initially scaled into a fixed block size, e.g., a block size of 16 x 16 pixels. Each character is then encoded into a 'character bitstream' using the intra macroblock coding syntax. The character bitstream is stored within a storage medium. When a frame of OSD messages needs to be encoded, the character bitstreams are read from the storage medium and cascaded to form a valid OSD message bitstream which represents the frame of OSD messages.

Claims

AMENDED CLAIMS

[received by the International Bureau on 22 November 1996 (22.11.96);

original claim 16 cancelled; original claims 1, 3, 4, 6, 12, 17 and 18 amended;

new claims 19-23 added; remaining claims unchanged (4 pages)]

1. A method of constructing an On-Screen Display (OSD) message bitstream representing an OSD message, comprising the steps of:

scaling each character of an OSD font set into a fixed block size to produce a set of scaled OSD characters;

encoding each of said scaled OSD character into one of said plurality of character bitstreams; and

storing said plurality of character bitstreams into a storage medium: reading a plurality of said character bitstreams representing the OSD message from said storage medium; and

cascading said plurality of character bitstreams into said OSD message bitstream.

2. The method of claim 1, further comprises the step of:

inserting a slice start code before each of said plurality of character bitstreams.

3. The method of claim 1, wherein said OSD message bitstream is MPEG-compliant.

4. The method of claim 1. wherein said storage medium is a read only memory (ROM).

5. The method of claim 3, wherein said fixed block size is a

macroblock.

6. A method of generating character bitstreams for a plurality of OSD characters, comprising the steps of:

scaling each of the OSD characters into a fixed block size to produce a set of scaled OSD characters; and

encoding each of said scaled OSD characters into one of said plurality of character bitstreams.

7. The method of claim 6, further comprises the step of: storing each of the character bitstreams into a storage medium. 8. The method of claim 7, wherein said storage medium is a read only memory (ROM).

9. The method of claim 6, wherein said fixed block size is a inacroblock.

10. An OSD message bitstream itored in a storage medium

comprising:

a plurality of character bitstreams; and

a plurality of slice start codes, where each of said plurality of character bitstreams is preceded by one of said plurality of slice start codes.

11. The bitstream of claim 10, wherein said slice start code is in accordance with the MPEG standards.

12. An apparatus for generating an OSD message bitstream

comprising:

a storage medium;

an encoder, coupled to said storage medium, for encoding a plurality of OSD characters into a plurality of character bitstreams, where said plurality of character bitstreams are stored in said storage medium;

a centra] processing unit (CPU), coupled to said storage medium, for selectively reading said plurality of character bitstreams from said storage medium, where said CPU cascades said plurality of character bitstreams to form the OSD message bitstream; and

a character sealer, coupled to said encoder, for scaling each of said plurality of OSD characters into a fixed block size before said plurality of OSD characters are encoded. 13. The apparatus of claim 12, further comprises a memory, coupled to said CPU, where said encoder is implemented as an algorithm stored within said memory and executed by said CPU.

14. The apparatus of claim 12, wherein said storage medium is a read only memory (ROM).

15. The apparatus of claim 12, wherein said encoder is a MPEG- compliant encoder.

17. The apparatus of claim 15 wherein said fixed block size is a macroblock. 18. The apparatus of claim 12 wherein said character sealer is implemented as an algorithm stored within said memory and executed by said CPU.

19. An apparatus for generating an OSD message bitstream

comprising:

a storage medium;

an encoder, coupled to said storage medium and having a quantizer, for encoding a plurality of OSD charactrs into a plurality of character bitstreams, where said plurality of character bitstreams are stored in said storage medium; and

a central processing unit (CPU), coupled to said storage medium, for selectively reading said plurality of character bitstreams from said storage medium, where said CPU cascades said plurality of character bitstreams to form the OSD message bitstream.

20. A method of encoding an On-Screen Display (OSD) siganl and a non-On-Screen Display (OSD) into the same type of output format, comprising the steps of:

distinquishing between said OSD input and said non-OSD input;

encoding said OSD input in a first way by reading a plurality of character bitstreams representing each character of said OSD input from a storage medium, cascading said plurality of character bitstreams into an OSD message bitstream output; and

encoding said non-OSD input into an output in a second way, said second way different from said first way,

21. The method of claim 20, wherein said output format is MPEG compliant.

22. An apparatus for encoding an On-Screen Display (OSD) siganl and a non-On-Screen Display (OSD) into the same type of output format, comprising:

a storage medium;

an encoder, coupled to said storage medium, for encoding said OSD input in a first way by reading a plurality of character bitstreams representing each character of said OSD input from said storage medium, said encoder cascading said plurality of character bitstreams into an OSD message bitstream output; and

said encoder encoding said non-OSD input into an output in a second way, said second way different from said first way.

23. The apparatus of claim 22, wherein said output format is MPEG compliant.