KR100249219B1 - OSD device - Google Patents

Abstract

The present invention saves the cursor bitmap in the internal buffer of the OSD controller and outputs the cursor bitmap by accepting only the position information from an external microprocessor, thereby greatly reducing the amount of data transfer between the external memory and the OSD controller. A memory for storing OSD bitmap data and cursor bitmap data, a first buffer for loading bitmap data of a cursor in accordance with a predetermined control signal from the memory, and an OSD bitmap from the memory. And a second buffer for loading data according to a predetermined control signal, and a multiplexer for selecting and outputting the outputs of the first and second buffers according to the OSD control signal and the position information of the cursor.

Description

OSD device {OSD device}

The present invention relates to an On Screen Display (OSD) device, and specifically, a cursor bitmap is stored in an internal buffer of the OSD controller, and only the positional information is received from the external microprocessor and outputted. The present invention relates to an OSD device which greatly reduces the data transmission amount of a device and improves overall performance.

The OSD device may provide other information such as subtitles other than image data displayed to the user, and may allow the user to alternately use the image processing system.

In the OSD device, for example, when the character OSD is represented as an OSD bitmap, the OSD device may be configured as 2 bits, 4 bits, or n bits as shown in FIG. 1.

FIG. 1A illustrates a case in which one pixel is 2 bits, and FIG. 1B illustrates a case in which 4 bits represent one pixel. In FIG. 1A, the letter “D” is a binary number. (Binary) shows a bitmap composed of "11" and the background is "00". In FIG. 1B, the character "S" is binary "1010" and the background is "0000". Represents a bitmap.

In general, the OSD uses a 16-entry CLUT (Colar Look-Up Table), where CLUT refers to a table that stores color information representing the OSD, that is, Y, CB, and CR.

When the number of entries of the CLUT is 16, when using a 2-bit / pixel bitmap as shown in FIG. 2A, the bitmap cannot be directly used as an address to the CLUT. Therefore, a color map is required in an intermediate step.

That is, this color map is for 2-to-4 address change, and when the OSD bitmap is "11", the last entry of the color map is accessed and "1001" is output as a result.

The output " 1001 " is again used as an address input of the CLUT so that Y, CB, and CR values stored in the ninth (since the input address is " 1001 ") are finally OSD outputs.

However, in the case of 4 bits / pixel, since the bitmap itself can be directly used as an input address as shown in FIG. 2B, a color map is not necessary as described above, and when the bitmap input is "1010", the 10th The Y, CB, and CR stored in the entry are finally output and displayed.

And, if the bitmap is represented by 4 bits / pixel or more, the CLUT must have 16 entries or more.

The size of the OSD bitmap can generally be up to 720 × 480 (NTSC) or 720 × 576 (PAL). If the bitmap is large in size, the amount of memory data transfer between the external memory and the OSD controller is increased.

However, unlike a normal image, the OSD screen is very small over time. For example, in the case of caption, the bitmap does not change for approximately 50-60 frames because the same bitmap is maintained for 1-2 seconds.

Also, in case of OSD screen such as menu selection on the initial screen, the OSD bitmap does not change until the viewer selects the menu.

In other words, general OSD bitmaps have little movement, so data transfer to update the OSD bitmap between the external memory and the OSD controller is not a problem, but when the cursor is used on the OSD screen, the shape of the cursor itself is fixed. However, the problem is caused by the characteristic of the cursor that the degree of movement is more severe than the general OSD bitmap.

For example, in the initial menu selection screen, the OSD background bitmap does not change, but the viewer must update the entire OSD bitmap each time he moves the cursor to see that the cursor is moving as he intended on the OSD screen. The OSD bitmap with the cursor needs to update the OSD bitmap more frequently than in other cases, which leads to an increase in the amount of memory data transfer between the external memory and the OSD controller.

In general, the OSD device is a part of the image processing system, and when the amount of memory data transfer by the OSD device increases, the overall performance of the image processing system is deteriorated.

Accordingly, the present invention has been invented in view of such a conventional problem, and the cursor bitmap is stored in an internal buffer of the OSD controller, and then the cursor bitmap is output by accepting only position information from an external microprocessor. The present invention provides an OSD device that greatly reduces the amount of memory data transfer between OSD controllers to improve overall performance.

1 is a view schematically showing the configuration of an OSD bitmap

2A and 2B schematically illustrate a method of displaying an OSD bitmap.

3 is a block diagram schematically showing an OSD device of the present invention.

Explanation of symbols for main parts of the drawings

10: external microprocessor 11: memory

12, 13: buffer 14: multiplexer

15: OSD controller 16: host interface

The object of the present invention is a memory for storing OSD bitmap data and cursor bitmap data, a first buffer for loading bitmap data of a cursor in accordance with a predetermined control signal from the memory, and an OSD from the memory. An OSD device including a second buffer for loading bitmap data according to a predetermined control signal, and a multiplexer for selecting and outputting outputs of the first buffer and the second buffer according to OSD control signals and cursor position information; Is achieved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 schematically illustrates an embodiment of the present invention, which includes an external memory 11 storing OSD bitmap data and cursor bitmap data, and a first buffer loading cursor bitmap data from the memory 11. 12, a second buffer 13 for loading OSD bitmap data from the memory 11, OSD control signals from an external microprocessor 10 and position information of the cursor according to the position information of the cursor. And a multiplexer 14 for selecting and outputting outputs of the first buffers 12 and 13, wherein the first and second buffers 12 and 13 and the multiplexer 14 are formed inside the OSD controller 15. have.

In addition, reference numeral 16 is a host interface for connecting the external microprocessor 10 to the external memory 11 and the OSD controller 15.

According to the OSD device of the present invention configured as described above, after storing the OSD bitmap data and the cursor bitmap data in the external memory 11 by the external microprocessor 10, the external microprocessor 10 or the OSD controller 15 again. After loading the cursor bitmap data into the first buffer 12 and the OSD bitmap data into the second buffer 13 according to an internal control signal, the external microprocessor 10 or the OSD controller ( The multiplexer 14 selects the outputs of the first buffer 12 and the second buffer 13 according to the OSD control signal and the position information of the cursor from 15) to display the cursor in the OSD device.

As described above, the OSD device of the present invention has no change in the shape of the cursor itself in the OSD screen including the cursor, but the bitmap of the cursor is large in consideration of the large amount of data transmission for updating the bitmap of the cursor due to the large variation in the position. Because the data is stored in the internal buffer of the OSD controller and only the position information is received from the external microprocessor, the cursor is displayed on the screen. Thus, the data transfer volume for updating is significantly reduced compared to the conventional method of updating the entire OSD bitmap data. This prevents the overall performance of the image processing device from being deteriorated due to the increase in the amount of memory data transfer, and because the cursor is very small, a buffer for storing the cursor bitmap data inside the hardware of the OSD controller can be implemented at a low price. Has the effect of.

Claims (2)

A memory for storing the OSD bitmap data and the cursor bitmap data, respectively; A first buffer for loading bitmap data of a cursor in accordance with a predetermined control signal from the memory; A second buffer for loading OSD bitmap data from the memory according to a predetermined control signal; And a multiplexer for selecting and outputting bitmap data of the cursor output from the first buffer and OSD bitmap data output from the second buffer according to an OSD control signal and cursor position information. The method of claim 1, And the first and second buffers and multiplexers are formed inside the OSD controller.

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