KR100744519B1 - Device for an on screen display scaling and the method thereof - Google Patents

Abstract

An OSD(On Screen Display) scaling apparatus and a method thereof are provided to process a digital broadcasting video signal without adding an additional memory access interface or deinterlacing circuit to an OSD apparatus. A main scaler(221) adjusts size of a main image. A sub-scaler(222) adjusts size of a sub-image. The first switch transfers a digital broadcasting video signal of an external input image to the main scaler or the sub-scaler. A scaler exclusive frame memory stores a scaled image. An OSD frame memory stores a graphic image. The second switch accesses the OSD frame memory and the scaler exclusive frame memory. A blending part mixes the main image, the sub-image and a video or graphic image read from at least one of the OSD frame memory and the scaler exclusive frame memory. A control part(230) controls the main scaler and the sub-scaler so that the main scaler and the sub-scaler scales the image stored in the scaler exclusive frame memory into an image having designated image size.

Description

Device for an On Screen Display Scaling and the method

1 is a pixel diagram of image data for on-screen display (OSD) scaling.

2 illustrates an example of converting a 4: 2: 0 video image into a 4: 4: 4 video image.

3 is a block diagram showing a configuration of an on-screen display scaling apparatus according to the prior art.

4 is a block diagram showing the configuration of an on-screen display scaling device according to the present invention.

5 is a flowchart illustrating a process of an on-screen display scaling method according to the present invention.

The present invention relates to a digital video display device, and more particularly, to an apparatus and method for processing an external input image or a digital broadcast video image and a graphic image having different color sampling methods using a scaler and an OSD.

1 is a pixel diagram of image data for on-screen display (OSD) scaling. The graphic image targeted by the graphics engine is configured such that 16 bits or 24 bits include one luminance signal and two color difference signals. The bit resolution of the image targeted by the scaler has a 4: 2: 0, 4: 2: 2 or 4: 4: 4 sampling format. The 4: 4: 4 sampling format (a) has a luminance signal? And two color difference signals? Having the same position. The 4: 2: 2 sampling format (b) is a sub-sampled color difference signal (차) component horizontally compared to the 4: 4: 4 sampling format. The 4: 2: 0 sampling format is a sub-sampled color difference signal (o) component horizontally and vertically compared to the 4: 4: 4 sampling format (c, d).

Digital broadcast video signals having a 4: 2: 0 sampling format have a format very different from the 4: 2: 2 sampling format. The conversion from 4: 2: 2 sampling format to 4: 4: 4 sampling format is easy to implement by using horizontal interpolation alone. However, as shown in Fig. 2, the conversion from 4: 2: 0 sampling format to 4: 4: 4 sampling format requires not only horizontal but also vertical interpolation method, and therefore, an interpolation method using a separate line memory must be used. It is not easy to implement. Also, as shown in Figs. 1C and 4D, the 4: 2: 0 sampling formats of MPEG-1 and MPEG-2 are different, so they must be coped with.

3 is a block diagram showing the configuration of an on-screen display scaling apparatus according to the prior art. Looking at the configuration, the switch 110 for inputting the digital broadcast video signal of the external input image or the video decoder buffer 161 to the scalers 121, 122, and the size of the main image transmitted through the switch 110 A main video scaler 121 for adjusting, a sub video scaler 122 for adjusting the size of the sub-picture, a synthesizer 130 for synthesizing the signals provided by the two scalers 121 and 122, and a buffer of the frame memory 161, 162, 163 and memory blocks 151, 152, 153 for storing temporary data.

Due to the different pixel configurations, the OSD dedicated memory access interface and the scaler dedicated memory access interface have different operations. For display output, no matter what sampling format the original data is, the video scaler and OSD must output 24-bit pixel data with a 4: 4: 4 sampling format. Therefore, the video scaler and the OSD differ in the interpolation method to the 4: 4: 4 sampling format according to the sampling format of the original data.

Digital video consists of a chrominance signal and a luminance signal produced by subsampling a color signal to reduce the amount of video information for transmission. Most external input video signals have a 4: 4: 4 or 4: 2: 2 sampling format. Video signals for digital TV broadcasting have a 4: 2: 0 sampling format. That is, the color signal of the external input video has all of the primary color signals or half of the information thereof, and the color signal of the digital broadcast video has information corresponding to 1/4 of the primary color signal. Therefore, in order for the scaler to store or read such video signals, a dedicated scaler memory interface is used to suit the particular sampling format. In addition, a scaler dedicated frame memory area is allocated to the external memory, and in order to access the area, a memory interface having the same method as the scaler dedicated memory interface operates must be used.

The OSD is responsible for blending the graphical image into the scaled video image. In other words, the OSD-only frame buffer is configured independently in external memory so that the CPU or graphics engine draws a graphic image with 4: 4: 4 or 4: 2: 2 sampling format into the OSD-only frame buffer, and the OSD has its own frame. It reads the graphic image written to memory and blends it with the main video signal coming into a separate input port.

Accordingly, the scaler dedicated frame memory and the OSD dedicated frame memory support different memory access methods, and in order for the scaler and the OSD to access each other's frame memory, the memory access interface must be additionally installed.

In addition, when the video image and the graphic image are blended with each other, the 4: 4: 4 sampling format for display output must be maintained. Therefore, the scaler converts the 4: 2: 2 or 4: 4: 4 sampling format to 4: 4: 4 sampling format while scaling the color difference signal of the external input, and has a 4: 2: 0 sampling format. Scaling for broadcast video signals also converts to 4: 4: 4 sampling format.

The OSD processes the image with a 4: 4: 4 or 4: 2: 2 sampling format, blending it with the video image. In addition, the scaler converts a digital broadcast video signal having an interlaced signal method into a progressive signal method to process video processing. Not only is this circuit very complex, it only applies to interlaced video inputs, and it is very inefficient to implement it in an OSD that processes graphical images.

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Therefore, in order for the OSD to process digital broadcast video signals, a separate memory block supporting a 4: 2: 0 sampling format and a scaling block capable of converting inputs and outputs into various sizes must be mounted as separate circuits.

An object of the present invention is to provide an apparatus and method for maintaining an OSD processing a graphic image and enabling an OSD circuit to process a digital broadcast video signal using an existing scaler.

It is another object of the present invention to provide an apparatus and method for processing digital broadcast video signals without the addition of a separate 4: 2: 0 memory access interface or deinterlacing circuitry to the OSD device.

According to an aspect of the present invention, an on-screen display scaling method according to the present invention is characterized by outputting a scaled video image through an OSD by sharing a memory access interface of a scaler in an on-screen display (OSD) circuit. do.

Another aspect of the on-screen display scaling method according to the present invention comprises the steps of: scaling an input broadcast video signal into a 4: 2: 2 sampling format; Storing the scaled broadcast video signal in a scaler dedicated memory; And selecting and synthesizing one or more of the stored broadcast video signal or the graphic image stored in the OSD buffer.
The input broadcast video signal may be configured to support a 4: 2: 0 sampling format.

An on-screen display scaling device according to the present invention comprises: a scaler dedicated frame memory; A scaling unit for converting a sampling format of a digital broadcast signal and / or a graphic image to store in the scaler dedicated frame memory and to scale the stored data; And a OSD processing unit for synthesizing the main screen and the sub-screen scaled by the scaling unit.

Features of the detailed configuration of the on-screen display scaling apparatus according to the present invention includes a main scaler for adjusting the size of the main image; A sub-scaler for adjusting the size of the sub-image; A first switch for transmitting a digital broadcast video signal of an external input video or video decoder dedicated frame memory to the primary and / or secondary scalers; A scaler dedicated frame memory for storing the scaled image; A second switch capable of accessing an OSD frame memory or a scaling dedicated frame memory; A blending unit configured to synthesize a video or graphic image read from the main image, the sub-image, the OSD frame memory, and the scaling frame memory; And a controller which controls the main scaler and the subscaler to scale the image stored in the scaler dedicated frame memory to a specified output size.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings. Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described by at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

The OSD can read 16-bit or 24-bit graphic images from memory to produce a single pixel, and video images have 24-bit pixel data in the 4: 4: 4 sampling format if the original data is in the 4: 2: 0 sampling format. In order to produce the reference, we need to refer to the chrominance signal in the vertical direction as well as in the horizontal direction, that is, the line other than the current line. This requires a complex algorithm that takes into account separate line memories and interlace or progressive scan of the original input. OSD scaling for video images requires that the OSD be equipped with a memory access interface that can process a separate video image, resulting in increased complexity and hardware.

Thus, the OSD can process the scaled video image while maintaining the existing hardware structure in such a manner that the OSD shares the memory access interface of the scaler.

4 is a block diagram showing the configuration of an on-screen display scaling device according to the present invention. Looking at the configuration, it can be seen that unlike the prior art, a synthesizer is not required, and a switch 212 is further formed between the OSD buffer 263 and the memory block 253. In addition, the image provided from the main scaler 221 and the sub-scaler 222 is configured to be blended with the signal provided through the OSD buffer according to the control signal of the controller 230 to display on-screen.

The video decoder decodes the digital broadcast image into a frame memory dedicated to the video decoder. At this time, the luminance signal and the chrominance signal are separated from each other, and the sampling format of the chrominance signal is 4: 2: 0 format. Also, as shown in Figs. 1C and 1D, the sampling formats of MPEG-1 and MPEG-2 are the same 4: 2: 0 format, but since the positions of the color difference signals are different from each other, this information is determined by the scaler. It is used to interpolate the color difference signal.

5 is a flowchart illustrating a process of an on-screen display scaling method according to the present invention.

When the digital broadcast image is selected as the OSD scaling target and the input size and the output size are determined (S51), the scaler reads the digital broadcast image using the scaler dedicated memory access interface (S52). In this process of reading, the data is converted from the 4: 2: 0 sampling format to the 4: 2: 2 sampling format (S53). The 4: 2: 2 sampling format image is thus scaled (S54). The scaled image is stored in the scaler dedicated frame memory (S55). At this time, the sampling format is 4: 2: 2 format.

The interlaced scan image is composed of the progressive scan image divided into even-numbered and odd-numbered images.In the OSD targeting the fine text or the image, the progressive scan image is displayed in terms of the image quality rather than the interlaced scan image. Superior

Therefore, if the digital broadcast image is an interlaced scan, the deinterlacer inside the scaler converts the interlaced image into a progressive scan and writes it to the scaler dedicated frame memory.

The OSD dedicated memory access interface accesses an image of the scaler dedicated frame memory to handle blending with the main screen. In this case, since the image of the frame memory is a 4: 2: 2 sampling format rather than a 4: 2: 0 sampling format, it is possible to access the existing OSD.

When the external input image is selected as the OSD scaling target and the output size is determined, the scaling process is performed through the same process. Another difference is that the color difference sampling format is 4: 2: 2 rather than 4: 2: 0. Therefore, the interpolation process of the separate color difference signal does not work.

In data broadcasting, a bitmap image of a certain size is used, which is largely different from the display format size. Thus, there is a need to scale to fit a variety of sizes, including display format sizes.

Once the graphic image is selected for OSD scaling and the output size is determined, the CPU causes the graphics engine to convert the existing 16-bit or 24-bit graphic image to 4: 2: 2 sampling format and write it to memory.

The control unit allows the scaler to scale the image written in the scaler dedicated frame memory to the designated output size (S56).

Finally, in the OSD, the main picture from the main video scaler output and the sub picture from the sub-scaler output may be synthesized (S57).

The OSD may use a video scaler and scaling memory access interface to process digital broadcast video images, external input images, or graphical images. This allows existing hardware resources: two video scaler and video scaler memory access interfaces, an OSD and OSD memory access interface to complete OSD scaling for a variety of video or graphic images without a separate OSD-only or OSD-only memory access interface. Can be handled.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

As described above, the on-screen display scaling apparatus according to the present invention has an effect of completely processing OSD scaling for various video or graphic images without using a conventional window synthesis unit.

Claims (5)

delete Scaling the input broadcast video signal into a 4: 2: 2 sampling format; Storing the scaled broadcast video signal in a scaler dedicated memory; And Selecting and synthesizing one or more of the stored broadcast video signal or the graphic image stored in the OSD buffer. The method of claim 2, And the input broadcast video signal supports a 4: 2: 0 sampling format.       A main scaler for adjusting the size of the main image;       A sub-scaler for adjusting the size of the sub-image;      A first switch for transmitting a digital broadcast video signal of an external input image to the primary scaler and / or the secondary scaler;       A scaler dedicated frame memory for storing the scaled image;       An OSD frame memory for storing a graphic image;       A second switch capable of accessing the OSD frame memory or the scaling dedicated frame memory;       A blending unit configured to synthesize a video or graphic image read from at least one of a main image, a sub-image, an OSD frame memory, and a scaling frame memory; And a controller configured to control the main scaler and the subscaler to scale an image stored in a scaler-only frame memory to a specified output size. The method of claim 2, And converting the OSD signal format into a 4: 2: 2 sampling format while the scaler reads an input image using a scaler dedicated memory access interface.

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