System and method for overlaying images from multiple video sources on a display device

• US 20060028583A1
• Filed: 08/04/2004
• Published: 02/09/2006
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: Entropic Communications Incorporated (Maxlinear Incorporated)
• Original Assignee: Trident Microsystems Limited (Avnet Incorporated)
• Inventors: Jiang, Jiande, Lin, Walter C.
• Granted Patent: US 7,250,983 B2
• Time in Patent Office: Days
• US Class Current: 348/584
• CPC Class Codes: G09G 2310/0229 De-interlacing
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2340/12 Overlay of images, i.e. displayed pixel being the result of switching between the corresponding input pixels
• CPC Class Codes: G09G 2340/125 wherein one of the images is motion video
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 5/14 Display of multiple viewports
• CPC Class Codes: G09G 5/391 Resolution modifying circuits, e.g. variable screen formats
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence
• CPC Class Codes: G09G 5/397 Arrangements specially adapted for transferring the contents of two or more bit-mapped memories to the screen simultaneously, e.g. for mixing or overlay G09G5/02 takes precedence
• CPC Class Codes: H04N 21/4316 for displaying supplemental content in a region of the screen, e.g. an advertisement in a separate window
• CPC Class Codes: H04N 21/440218 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 conversion of standards in analogue television systems H04N7/01
• CPC Class Codes: H04N 21/440263 by altering the spatial resolution, e.g. for displaying on a connected PDA
• CPC Class Codes: H04N 21/440281 by altering the temporal resolution, e.g. by frame skipping television signal recording using magnetic recording on tape for reproducing at a rate different from the recording rate H04N5/783
• CPC Class Codes: H04N 5/45 Picture in picture , e.g. displaying simultaneously another television channel in a region of the screen
• CPC Class Codes: H04N 7/012 Conversion between an interlaced and a progressive signal for graphics images G09G2310/0229

Abstract

The present invention provides a system and method for overlaying video from different video sources on a display device. The sources may include a primary video source that provides first image data in the form of a first video signal, and an overlay video source that provides second image data in the form of a second video signal and a fast blank signal. The system encodes the fast blank signal into the second video signal to form encoded image data. The fast blank signal can occupy one bit of the encoded image data. The system stores the first image data and the encoded image data in a frame buffer. A controller reads the first image data and the encoded image data from the frame buffer. The controller processes and decodes encoded image data, extracting the fast blank signal. The controller then uses the extracted fast blank signal to combine the second image data and the first image data, effective to overlay an image from the overly video source onto an image from the primary video source.

Claims

1. A system for combining images from a first video source and a second video source on a display device, the system comprising:

a frame buffer for storing image data;

a first circuit that stores first image data from the first video source in the frame buffer, that encodes a fast blank signal into second image data from the second video source to form encoded image data, and that stores the encoded image data in the frame buffer;

a second circuit that reads the first image data and the encoded image data from the frame buffer, and that decodes the encoded image data to separate the fast blank signal and the second image data; and

a third circuit that uses the fast blank signal to selectively transmit the first image data and the second image data to the display device, effective to cause the display device to display an image from the second video source overlaid onto an image from the first video source.

2. The system of claim 1 wherein the first circuit is further adapted to convert the first image data and second image data from analog data into digital data.

3. The system of claim 2 wherein the first circuit converts the second image data into a multi-bit signal and encodes the fast blank signal as a single value in the multi-bit signal.

4. The system of claim 1 wherein the second circuit is further adapted to process at least some of the image data.

5. The system of claim 4 wherein the second circuit comprises a de-interlacing circuit for de-interlacing image data.

6. The system of claim 4 wherein the second circuit comprises a scaler for scaling image data.

7. The system of claim 4 wherein the second circuit comprises a frame rate conversion circuit.

8. The system of claim 4 wherein the third circuit comprises a multiplexer.

9. A system for overlaying images from first and second video sources on a display device, the system comprising:

a frame buffer for storing image data; and

a controller that receives first image data from the first video source and second image data and a fast blank signal from the second video source, and that stores and reads image data in the frame buffer, the controller comprising;

an encoding circuit that encodes the fast blank signal into the second image data, effective to form encoded image data, and that transmits the encoded image data to the frame buffer for storage;

a processing and decoding circuit that receives the first image data and the encoded image data from the frame buffer, that processes the image data and that decodes the encoded image data to separate the fast blank signal and the second image data;

a combiner that receives the first image data, second image data and fast blank signal, and that uses the fast blank signal to selectively transmit the first image data and the second image data to the display device, effective to cause the display device to display an image from the second video source overlaid onto an image from the first video source.

10. The system of claim 9 wherein the controller receives first image data and second image data in the form of analog signals.

11. The system of claim 10 wherein controller is adapted to convert the analog signals into digital data.

12. The system of claim 9 wherein the second image data comprises a multi-bit digital signal, and wherein the encoding circuit encodes the fast blank signal into the second image data by storing the fast blank signal as a one bit value of the second image data.

13. The system of claim 12 wherein the multi-bit digital signal is a sixteen bit digital signal.

14. The system of claim 9 wherein the frame buffer includes a first portion for storing the first image data and a second portion for storing the second image data.

15. The system of claim 9 wherein the combiner comprises a multiplexer.

16. The system of claim 9 wherein the processing and decoding circuit is adapted to de-interlace at least one of the first and second image data.

17. The system of claim 9 wherein the processing and decoding circuit is adapted to scale at least one of the first and second image data.

18. The system of claim 9 wherein the processing and decoding circuit is adapted to perform frame rate conversion on at least one of the first and second image data.

19. A method for overlaying images from first and second video sources on a display device, the method comprising:

receiving first image data from the first video source;

receiving second image data from the second video source;

receiving a fast blank signal associated with the second image data;

encoding the fast blank signal into the second image data, effective to form encoded image data;

storing the first image data and encoded image data in a frame buffer;

reading the first image data and encoded image data from the frame buffer;

decoding the encoded image data to separate the fast blank signal and the second image data; and

using the fast blank signal to selectively transmit the first image data and the second image data to the display device, effective to cause the display device to display an image from the second video source overlaid onto an image from the first video source.

20. The method of claim 19 wherein the first image data, second image data and fast blank signal are received in the form of analog signals.

21. The method of claim 20 further comprising:

converting the analog signals into digital signals before storing the first and encoded image data in the frame buffer.

22. The method of claim 19 wherein the second image data comprises a multi-bit digital signal, and wherein the fast blank signal is encoded into the second image data by storing the fast blank signal as a one-bit value of the multi-bit digital signal.

23. The method of claim 19 further comprising:

processing at least one of the first and second image data.

24. The method of claim 23 wherein the processing comprises de-interlacing.

25. The method of claim 23 wherein the processing comprises scaling.

26. The method of claim 23 wherein the processing comprises frame rate conversion.