Preventing image tearing where a single video input is streamed to two independent display devices

• US 20070024524A1
• Filed: 07/28/2005
• Published: 02/01/2007
• Est. Priority Date: 07/28/2005
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Lai, Jimmy
• Granted Patent: US 7,542,010 B2
• Time in Patent Office: Days
• US Class Current: 345/1.100
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• 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 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

Abstract

The invention is generally directed to methods and apparatus for preventing image tearing where a single video input is streamed to two or more independent display devices for simultaneous display. A preferred method includes: (a) receiving a sequence of frames from an image data source for refreshing a first display device and at least a second display device; (b) storing a first, sequential frame in the sequence in a first buffer; (c) storing a second, sequential frame in the sequence in a second buffer; (d) refreshing the first display device from the first buffer; (e) refreshing the second display device from the first buffer; (f) determining whether the steps (d) and (e) of refreshing the first and second display devices are complete; and (g) storing a third, sequential frame in the sequence in the first buffer, provided the steps (d) and (e) of refreshing are complete.

Claims

1. A method for preventing image tearing where a single input is streamed to two or more independent display devices for simultaneous display, comprising:

(a) receiving a sequence of frames from a data source for refreshing a first output device and at least a second output device;

(b) storing a first, sequential frame in the sequence in a first buffer;

(c) storing a second, sequential frame in the sequence in a second buffer;

(d) refreshing the first output device from the first buffer;

(e) refreshing the second output device from the first buffer;

(f) determining whether the steps (d) and (e) of refreshing the first and second display devices are complete; and

(g) storing a third, sequential frame in the sequence in the first buffer, provided the steps (d) and (e) of refreshing are complete.

2. The method of claim 1, wherein the first output device and the second output device have different refresh rates.

3. The method of claim 1, wherein the first output device and the second device have different output resolutions.

4. The method of claim 1, wherein the data is audio data.

5. A graphics controller, comprising:

(a) an input interface unit for receiving a sequence of frames from a data source for refreshing a first output device and a second output device;

(b) a first buffer for storing a first, sequential frame in the sequence;

(c) a second buffer for storing a second, sequential frame in the sequence;

(e) a first output interface for refreshing the first output device from the first buffer;

(e) a second output interface for refreshing the second output device from the first buffer;

(f) a write control unit for permitting the input interface unit to store a third, sequential frame in the sequence in the first buffer, provided the refreshing of the first and second display devices are complete.

6. The graphics controller of claim 5, wherein the first output device and the second output device have different refresh rates.

7. The graphics controller of claim 5, wherein the first output device and the second device have different output resolutions.

8. The graphics controller of claim 5, wherein the data is audio data.

9. A graphics display system, comprising:

a host;

a first output device and at least a second output device;

a data source for providing sequence of frames of data for simultaneous rendering on the first output device and the second output device;

a memory having a first buffer for storing a first, sequential frame in the sequence, and a second buffer for storing a second, sequential frame in the sequence; and

a graphics controller, including;

(a) an input interface unit for receiving the sequence of frames;

(b) a first output interface for refreshing the first output device from the first buffer;

(c) a second output interface for refreshing the second output device from the first buffer; and

(d) a write control unit for permitting the input interface unit to store a third, sequential frame in the sequence in the first buffer, provided the refreshing of the first and second display devices are complete.

10. The graphics display system of claim 9, wherein the first output device and the second output device have different refresh rates.

11. The graphics display system of claim 9, wherein the first output device and the second device have different output resolutions.

12. The graphics display system of claim 9, wherein the data is audio data.