On screen display processor

• US 6,417,888 B1
• Filed: 10/09/1998
• Issued: 07/09/2002
• Est. Priority Date: 10/09/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Colavito, Leonard, Dunn, Perry S., Ravi, Sharmila
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US09/169,725
• Time in Patent Office: 1,369 Days
• Field of Search: 348/714, 348/716, 348/718, 348/578, 348/511, 348/906, 348/569, 345/123, 345/124, 345/125, 345/121
• US Class Current: 348/569
• CPC Class Codes: H04N 21/4312 involving specific graphical features, e.g. screen layout, special fonts or colors, blinking icons, highlights or animations
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/4884 for displaying subtitles
• CPC Class Codes: H04N 5/44504 Circuit details of the additional information generator, e.g. details of the character or graphics signal generator, overlay mixing circuits

Abstract

A decoder of an encoded video signal representing a video image includes an apparatus for scrolling an on screen display of closed caption information that is included in the encoded video signal. The apparatus decodes the closed caption data from the encoded video signal as a sequence of lines of on screen display data. An on screen display processor alternately stores successive groups of lines of the sequence of lines in a first memory buffer and in a second memory buffer where each successive group of lines is shifted by at least one line with respect to the previous group of lines. A display processor alternately displays the on screen display data from the first memory buffer and the second memory buffer synchronized with the storage into the buffers whereby the most recently stored group of lines is displayed. Rather than using first and second buffers, lines of on screen display data may be stored in a linked list of memory storage regions. On screen display information stored in the linked list is transferred to the display processor to produce the on screen display. To scroll the on screen display, a memory region is added to one end of the linked list and a memory region is dropped from the other end of the linked list where the added memory region stores a successive line of on screen display data from the sequence of lines of on screen display data.

Claims

1. An apparatus for scrolling an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the apparatus comprising:

means for receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

memory means including a first buffer and a second buffer;

on screen display processing means for storing a group of lines of the sequence of lines of the on screen display data in the first buffer and alternately storing successive groups of lines of the sequence of lines of the on screen display data in the second buffer and the first buffer, wherein each successive group of lines includes a plurality of lines from the previous group of lines and is shifted by at least one line in the sequence of lines of on screen display data with respect to the previous group of lines;

display means for alternately displaying the on screen display data from the first buffer and the second buffer synchronized with the storage of the successive groups of lines of the sequence of lines of the on screen display data in the second and first buffers, respectively, whereby the most recently stored group of lines is displayed.

2. The apparatus for scrolling an on screen display according to claim 1 wherein the encoded video signal is an MPEG-2 bitstream and the on screen display data is closed caption information which is encoded within a user data field of one of a sequence header, a group of pictures header, and a picture header.

3. The apparatus for scrolling an on screen display according to claim 1 wherein the on screen display is scrolled up by shifting each successive group of lines forward along the sequence of lines of the on screen display data.

4. The apparatus for scrolling an on screen display according to claim 1 wherein the on screen display is scrolled down by shifting each successive group of lines backward along the sequence of lines of the on screen display data.

5. An apparatus for scrolling an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the apparatus comprising:

means for receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

memory means including a plurality of storage regions;

on screen display processing means for forming a linked list of a group of storage regions, the linked list of storage regions having a first region and last region, storing a group of lines of the sequence of lines of the on screen display data in the linked list of storage regions, storing on screen display data corresponding to at least one successive line of the on screen display data along the sequence of lines of the on screen display data in one of the plurality of storage regions not currently in the linked list identified as the new link, and shifting the first region and the last region of the linked list to add a region and delete a region from the group of storage regions in the linked list so the added region is the new link; and

display means for displaying the group of lines of on screen data stored in the linked list.

6. An apparatus for scrolling an on screen display according to claim 5 wherein the region deleted from the group of storage regions and the region added to the group of storage regions are the same memory region.

7. An apparatus for scrolling an on screen display according to claim 5 wherein each of the sequence of lines of on screen display data is stored in a respectively different one of the plurality of storage regions in the linked list.

8. An apparatus for scrolling an on screen display according to claim 5 wherein each line of on screen display data corresponds to a raster line.

9. An apparatus for scrolling an on screen display according to claim 5 wherein each line of on screen display data corresponds to a character line.

10. The apparatus for scrolling an on screen display according to claim 5 wherein the encoded video signal is an MPEG-2 bitstream and the on screen display data is closed caption information, encoded within a user data field of one of a sequence header, a group of pictures header, and a picture header.

11. The apparatus for scrolling an on screen display according to claim 5 wherein the on screen display is scrolled up and the on screen display data stored in the new link includes a next successive line along the sequence of lines of on screen display data.

12. The apparatus for scrolling an on screen display according to claim 5 wherein the on screen display is scrolled down and the on screen display data stored in the new link includes a previous successive line along the sequence of lines of on screen display data.

13. An apparatus for scrolling up an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the apparatus comprising:

means for receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

memory means including a plurality of storage regions;

on screen display processing means for forming a linked list of a group of the plurality of storage regions, the linked list of storage regions having a first region and last region, storing a group of lines of the sequence of lines of the on screen display data in the linked list of storage regions where each storage region stores one respective line of on screen display data, storing on screen display data corresponding to a next line of the on screen display data along the sequence of lines of the on screen display data in the first region of the linked list, shifting a pointer to the first region in the linked list to point to the next region in the linked list and redefining the last region in the linked list to be the region storing the next line of the on screen display data; and

display means for displaying the group of lines of on screen data stored in the linked list.

14. A method for scrolling an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the method comprising the steps of:

(a) receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

(b) storing a group of lines of the sequence of lines of the on screen display data in a first buffer of a memory

(c) alternately storing successive groups of lines of the sequence of lines of the on screen display data in a second buffer of the memory and in the first buffer, wherein each successive group of lines includes a plurality of lines from the previous group of lines and is shifted by at least one line in the sequence of lines of on screen display data with respect to the previous group of lines; and

(d) alternately displaying the on screen display data from the first buffer and the second buffer synchronized with the storage of the successive groups of lines of the sequence of lines of the on screen display data in the second and first buffers, respectively, whereby the most recently stored group of lines is displayed.

15. A method for scrolling an on screen display according to claim 14 wherein the encoded video signal is an MPEG-2 bitstream and the on screen display data is closed caption information which is encoded within a user data field of one of a sequence header, a group of pictures header, and a picture header.

16. A method for scrolling an on screen display according to claim 14 wherein the on screen display is scrolled up by shifting each successive group of lines forward along the sequence of lines of the on screen display data.

17. The apparatus for scrolling an on screen display according to claim 14 wherein the on screen display is scrolled down by shifting each successive group of lines backward along the sequence of lines of the on screen display data.

18. A method for scrolling an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the method comprising the steps of:

(a) receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

(b) forming a linked list of a group of storage regions in a memory including a plurality of storage regions, the linked list of storage regions having a first region and last region;

(c) storing a group of lines of the sequence of lines of the on screen display data in the linked list of storage regions;

(d) storing on screen display data corresponding to at least one successive line of the on screen display data along the sequence of lines of the on screen display data in one of the plurality of storage regions not currently in the linked list identified as the new link;

(e) shifting the first region and the last region of the linked list to add a region and delete a region from the group of storage regions in the linked list so the added region is the new link; and

(f) displaying the group of lines of on screen data stored in the linked list.

19. A method for scrolling an on screen display according to claim 18 wherein the region deleted from the group of storage regions and the region added to the group of storage regions are the same memory region.

20. A method for scrolling an on screen display according to claim 18 wherein each of the sequence of lines of on screen display data is stored in a respectively different one of the plurality of storage regions in the linked list.

21. A method for scrolling an on screen display according to claim 18 wherein each line of on screen display data corresponds to a raster line.

22. A method for scrolling an on screen display according to claim 18 wherein each line of on screen display data corresponds to a character line.

23. A method for scrolling an on screen display according to claim 18 wherein the encoded video signal is an MPEG-2 bitstream and the on screen display data is closed caption information, encoded within a user data field of one of a sequence header, a group of pictures header, and a picture header.

24. A method for scrolling an on screen display according to claim 18 wherein the on screen display is scrolled up and the on screen display data stored in the new link includes a next successive line along the sequence of lines of on screen display data.

25. A method for scrolling an on screen display according to claim 18 wherein the on screen display is scrolled down and the on screen display data stored in the new link includes a previous successive line along the sequence of lines of on screen display data.

26. A method for scrolling up an on screen display using on screen display data, wherein the on screen display data is included in an encoded video signal representing a video image, the method comprising the steps of:

(a) receiving the encoded video signal and decoding the on screen display data as a sequence of lines of on screen display data;

(b) forming a linked list, in a memory including a plurality of storage regions, of a group of the plurality of storage regions, the linked list of storage regions having a first region and last region;

(c) storing a group of lines of the sequence of lines of the on screen display data in the linked list of storage regions where each storage region stores one respective line of on screen display data;

(d) storing on screen display data corresponding to a next line of the on screen display data along the sequence of lines of the on screen display data in the first region of the linked list;

(e) shifting a pointer to the first region in the linked list to point to the next region in the linked list and redefining the last region in the linked list to be the region storing the next line of the on screen display data; and

(f) displaying the group of lines of on screen data stored in the linked list.

27. A method for displaying video information including the steps of:

(a) receiving the video information as a sequence of lines of video information;

(b) forming a linked list, in a memory including a plurality of storage regions, of a group of the plurality of storage regions, the linked list of storage regions having a first region, a next region following the first region, and a last region;

(c) storing a group of lines of the sequence of lines of video information in the linked list of storage regions where each storage region stores one respective line of on screen display data;

(d) storing a next line of the video information along the sequence of lines of video information screen display data in the first region of the linked list;

(e) redefining the first region in the linked list to be the next region in the linked list and redefining the last region in the linked list to be the region storing the next line of the video information; and

(f) displaying the group of lines of video information stored in the linked list.