KR102523959B1 - Image processing device and method for operating image processing device - Google Patents

Abstract

An image processing device and an operating method of the image processing device are provided. The image processing apparatus includes a multimedia IP for processing image data including a first component and a second component; a memory accessed by the multimedia IP; and a Frame Buffer Compressor (FBC) configured to perform compression on the image data to generate compressed data and store the compressed data in the memory, wherein the frame buffer compressor comprises: and a compression management module for controlling a compression sequence of components and the second component.

Description

Image processing device and method of operating the image processing device {IMAGE PROCESSING DEVICE AND METHOD FOR OPERATING IMAGE PROCESSING DEVICE}

The present invention relates to an image processing device and an operating method of the image processing device.

As the need for high-resolution video and high-frame rate video has emerged, the amount of access to memory by various multimedia devices of an image processing device, ie, bandwidth, has greatly increased.

When the bandwidth increases, the processing capability of the image processing device reaches its limit, and a problem in that speed decreases during recording and playback of video images may occur.

Accordingly, when a multimedia device accesses a memory, a method of compressing the size of data is being considered. For example, data may be compressed before data is written to memory, and compressed data may be decompressed before data is read from memory.

A technical problem to be solved by the present invention is to provide an image processing apparatus that performs image data compression with excellent compression quality.

Another technical problem to be solved by the present invention is to provide an operating method of an image processing apparatus that performs image data compression with excellent compression quality.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

An image processing apparatus according to an embodiment of the present invention for achieving the above technical problem includes a multimedia apparatus for processing image data including a first component and a second component; memory accessed by the multimedia device; A frame buffer compressor (FBC) that performs compression on image data to generate compressed data and stores the compressed data in a memory, wherein the frame buffer compressor comprises a first component and a second component of the image data Includes a compression management module that controls the compression sequence of

An image processing apparatus according to another embodiment of the present invention for achieving the above technical problem includes a multimedia apparatus for processing image data conforming to the YUV format; memory accessed by the multimedia device; A frame buffer compressor that performs compression on image data to generate compressed data and stores the compressed data in a memory, wherein the frame buffer compressor includes a chroma component (chroma component) including Cb and Cr components in the YUV format of the image data. and a compression management module that controls a compression sequence so that compression of a component is performed prior to compression of a luma component including a Y component among YUV formats of image data.

A method of operating an image processing apparatus according to another embodiment of the present invention for achieving the above technical problem includes total target bits based on a target compression ratio for image data conforming to the YUV format. Computes chroma component target bits for compressing chroma components including Cb and Cr components in the YUV format, compresses chroma components by allocating chroma component target bits, and compresses data for chroma components Using chroma component used bits of , luma component target bits for the luma component including the Y component in the YUV format are calculated, the luma component target bits are allocated to compress the luma components, and for the luma component and adding a dummy bit after the compressed data for the luma component when the sum of the luma component used bits and the chroma component used bits of the compressed data is less than the total target bits.

Details of other embodiments are included in the detailed description and drawings.

1 to 3 are block diagrams illustrating an image processing apparatus according to some embodiments of the present invention.
4 is a block diagram for explaining the frame buffer compressor of FIGS. 1 to 3 in detail.
5 is a block diagram for explaining the encoder of FIG. 4 in detail.
FIG. 6 is a block diagram for explaining the decoder of FIG. 4 in detail.
7 is a conceptual diagram for explaining three operation modes for YUV 420 format data of an image processing apparatus according to some embodiments of the present invention.
8 is a conceptual diagram illustrating three operation modes for YUV 422 format data of an image processing apparatus according to some embodiments of the present invention.
9 to 11 are schematic diagrams for explaining an operation of an image processing apparatus for YUV 420 format data according to some embodiments of the present invention.
12 to 13 are schematic diagrams for explaining an operation of an image processing apparatus for YUV 422 format data according to some embodiments of the present invention.
15 is a flowchart illustrating an operating method of an image processing apparatus according to some embodiments of the present disclosure.

1 to 3 are block diagrams illustrating an image processing apparatus according to some embodiments of the present invention.

Referring to FIG. 1 , an image processing device according to some embodiments of the present invention includes a multimedia device 100, a frame buffer compressor (FBC) 200, a memory 300, and a system bus 400. do.

The multimedia device 100 may be a part that directly performs image processing of an image processing device. That is, the multimedia device 100 may refer to various modules for performing video recording and playback, such as camcoding and playback of video images.

The multimedia device 100 may receive first data from an external source such as a camera and convert it into second data. In this case, the first data may be video or image raw data. The second data is data generated by the multimedia device 100 and may also include data being processed by the multimedia device 100 . That is, the multimedia device 100 may repeat storing the second data in the memory 300 through several steps and updating again. The second data may include all data during this step. However, since the second data may be stored in the form of third data when stored in the memory 300, the second data in the memory 300 is stored before or in the memory 300. It may mean data after being read. This will be explained in more detail later.

Specifically, the multimedia device 100 includes an image signal processor (ISP) 110, a shake correction module (G2D) 120, a multi-format codec (MFC) 130, a GPU 140, and a display 150. can do. However, this embodiment is not limited thereto. That is, the multimedia device 100 may include at least some of the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 described above. That is, the multimedia device 100 may refer to a processing module that needs to access the memory 300 to process a video or image.

The image signal processor 110 may receive the first data and pre-process it to convert it into the second data. In this case, the first data may be RGB type image source data. For example, the image signal processor 110 may convert the first data of RGB format into the second data of YUV format.

At this time, the data of the RGB method means a data format in which colors are expressed based on the three primary colors of light. That is, it is a method of expressing an image using three types of colors: RED, GREEN, and BLUE. In contrast, the YUV method denotes a data format that separately expresses brightness, that is, a luminance (luma) signal and a color difference (chroma) signal. That is, Y denotes a luminance signal, and U(Cb) and V(Cr) denote color difference signals, respectively. U denotes a difference between the luminance signal and the blue signal component, and V denotes a difference between the luminance signal and the red signal component.

The YUV method data is converted from RGB method data using conversion equations such as Y=0.3R+0.59G +0.11B, U=(B-Y)x0.493, and V=(R-Y)x0.877, for example. and can be obtained.

Since the human eye is sensitive to luminance signals but less sensitive to color signals, YUV data may be more easily compressed than RGB data. Accordingly, the image signal processor 110 may convert the first data of the RGB method into the second data of the YUV method.

The image signal processor 110 may store the first data in the memory 300 after converting the second data.

The shake correction module 120 may perform shake correction of image or video data. The shake correction module 120 may perform shake correction by reading the first data or the second data stored in the memory 300 . In this case, shake correction means detecting camera shake in video data and removing it.

The shake correction module 120 may generate or update new second data by compensating for shake of the first data or the second data, and store it in the memory 300 .

The multi-format codec 130 may be a codec that compresses video data. In general, since video data is very large in size, a compression module that reduces its size is required. Video data can be compressed through association between a plurality of frames, and the multi-format codec 130 can perform this. The multi-format codec 130 may read and compress the first data or the second data stored in the memory 300 .

The multi-format codec 130 may compress the first data or the second data to generate new second data or update the second data, and store it in the memory 300 .

A graphics processing unit (GPU) 140 may calculate and generate 2D or 3D graphics. The GPU 140 may calculate and process the first data or the second data stored in the memory 300 . The GPU 140 is specialized in processing graphic data and can process graphic data in parallel.

The GPU 140 may compress the first data or the second data to generate new second data or update the second data, and store it in the memory 300 .

The display 150 may display the second data stored in the memory 300 on a screen. The display 150 displays image data processed by other multimedia devices 100, that is, the image signal processor 110, the shake correction module 120, the multi-format codec 130, and the GPU 140, that is, the second data. can be displayed on the screen. However, this embodiment is not limited thereto.

The image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 may operate individually. That is, the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display 150 can individually access the memory 300 to write or read data. there is.

The frame buffer compressor 200 compresses the second data and converts the second data into the third data before the multimedia device 100 individually accesses the memory 300 . The frame buffer compressor 200 may transmit the third data to the multimedia device 100 again, and the multimedia device 100 may transmit the third data to the memory 300 .

Accordingly, the third data compressed by the frame buffer compressor 200 may be stored in the memory 300 . Conversely, the third data stored in the memory 300 may be loaded by the multimedia device 100 and transmitted to the frame buffer compressor 200 . The frame buffer compressor 200 may decompress and convert the third data into the second data. The frame buffer compressor 200 may transmit the second data to the multimedia device 100 again.

That is, each time the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 individually access the memory 300. The frame buffer compressor 200 may compress the second data into the third data and transfer the compressed data to the memory 300 . Conversely, whenever there is a data request from the memory 300 to the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100. The frame buffer compressor 200 decompresses the third data into the second data, and the image signal processor 110, the shake compensation module 120, the multi-format codec 130, and the GPU 140 of the multimedia device 100 ) and the display 150, respectively.

The memory 300 may store the third data generated by the frame buffer compressor 200 and provide the stored third data to the frame buffer compressor 200 so that the frame buffer compressor 200 can decompress the stored third data. there is.

The system bus 400 may connect the multimedia device 100 and the memory 300 to each other. Specifically, the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 may be individually connected to the system bus 400. there is. The system bus 400 connects the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, the display 150, and the memory 300 of the multimedia device 100 to each other. can be a path to transmit.

The frame buffer compressor 200 is not connected to the system bus 400, and the image signal processor 110 of the multimedia device 100, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display When 150 accesses the memory, respectively, the second data may be converted into the third data, and the third data may be converted into the second data.

Referring next to FIG. 2 , the frame buffer compressor 200 of the image processing device according to some embodiments of the present invention may be directly connected to the system bus 400 .

The frame buffer compressor 200 is not directly connected to the multimedia device 100, but may be connected to each other through the system bus 400. Specifically, the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 are each connected to the frame buffer through the system bus 400. The compressor 200 and data may be transmitted to each other, and data may be transmitted to the memory 300 through this.

That is, in the compression process, the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 are connected through the system bus 400, respectively. The second data may be transmitted to the frame buffer compressor 200 . Subsequently, the frame buffer compressor 200 compresses the second data into the third data, and transmits it to the memory 300 through the system bus 400 again.

Similarly, in the decompression process, the frame buffer compressor 200 may receive the third data stored in the memory 300 through the system bus 400 and decompress it as the second data. Subsequently, the frame buffer compressor 200 transmits the second data through the system bus 400 to the image signal processor 110 of the multimedia device 100, the shake compensation module 120, the multi-format codec 130, and the GPU. 140 and the display 150 respectively.

Referring next to FIG. 3 , in an image processing device according to some embodiments of the present invention, a memory 300 and a system bus 400 may be connected to each other through a frame buffer compressor 200 .

That is, the memory 300 cannot be directly connected to the system bus 400 and can be connected to the system bus 400 only through the frame buffer compressor 200 . In addition, the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 may be directly connected to the system bus 400. Accordingly, the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100 only go through the frame buffer compressor 200 to the memory ( 300) can be accessed.

In this specification, the second data is also referred to as image data 10, and the third data is also referred to as compressed data 20.

4 is a block diagram for explaining the frame buffer compressor of FIGS. 1 to 3 in detail.

Referring to FIG. 4 , the frame buffer compressor 200 may include an encoder 210 and a decoder 220 .

The encoder 210 may receive image data 10 from the multimedia device 100 and generate compressed data 20 . At this time, the image data 10 may be transmitted from the image signal processor 110, the shake correction module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100, respectively. there is. The compressed data 20 may be transmitted to the memory 300 through the multimedia device 100 and the system bus 400 .

Conversely, the decoder 220 may decompress the compressed data 20 stored in the memory 300 into image data 10 . Image data 10 may be delivered to a multimedia device. At this time, the image data 10 may be transferred to the image signal processor 110, the shake compensation module 120, the multi-format codec 130, the GPU 140, and the display 150 of the multimedia device 100, respectively. there is.

5 is a block diagram for explaining the encoder of FIG. 4 in detail.

Referring to FIG. 5 , the encoder 210 includes a first mode selector 219 , a prediction module 211 , a quantization module 213 , an entropy encoding module 215 and a padding module 217 .

The first mode selector 219 may determine whether the encoder 210 operates in a lossless mode or a lossy mode. When the encoder 210 operates in the lossless mode according to the first mode selector 219, the image data 10 is compressed along the lossless path of FIG. 3 and the encoder 210 operates in the lossy mode. In case of operation, the image data 10 may be compressed along a lossy path (Lossy).

The first mode selector 219 may receive a signal for determining whether to perform lossless compression or lossy compression from the multimedia apparatus 100 . In this case, lossless compression means compression without loss of data, and means a method in which the compression rate varies depending on the data. On the other hand, lossy compression is compression in which data is partially lost, and has a higher compression rate than lossless compression and may have a preset, fixed compression rate.

In the case of the lossless mode, the first mode selector 219 may derive the image data 10 through the prediction module 211, the entropy encoding module 215, and the padding module 217 along a lossless path. . Conversely, in case of the lossy mode, the first mode selector 219 derives the image data 10 through the prediction module 211, the quantization module 213, and the entropy encoding module 215 along the loss path (Lossy). can

The prediction module 211 may represent the image data 10 by dividing it into prediction data and residual data. For example, when one pixel has a value of 0 to 255, 8-bit data per pixel may be required to represent it. In contrast, when adjacent pixels have similar values, there is no data loss even if only the difference between adjacent pixels, that is, the residual, is expressed, and the number of data bits to be expressed can be greatly reduced. For example, if pixels with values of (253, 254, 255) are consecutive and the prediction data is set to 253, the expression of the residual data of (253 (prediction), 1 (residual), 2 (residual)) is sufficient. And the number of bits per pixel for expressing the residual data can be very small, such as 2 bits.

Accordingly, the prediction module 211 may compress the size of the entire image data 10 by dividing the image data 10 into prediction data and residual data. Of course, various methods may be possible for what the prediction data is.

The prediction module 211 may perform prediction in units of pixels or in units of blocks. In this case, a block may mean an area formed by a plurality of adjacent pixels.

The quantization module 213 may additionally further compress the image data 10 compressed by the prediction module 211 . The quantization module 213 may remove lower bits of the image data 10 through a preset quantization coefficient. Specifically, a representative value is selected by multiplying data by a quantization coefficient, but loss may occur by discarding decimal places. If the value of pixel data is between 0 and 28-1 (= 255), the quantization coefficient may be defined as 1/(2n-1) (where n is an integer of 8 or less). However, this embodiment is not limited thereto.

In this case, the removed lower bit may be lost because it is not restored later. Thus, the quantization module 213 can only be utilized in lossy mode. However, since the lossy mode may have a relatively higher compression rate than the lossless mode and may have a preset fixed compression rate, information on the compression rate may not be separately required later.

The entropy encoding module 215 compresses the image data 10 compressed by the quantization module 213 in the lossy mode or the image data 10 compressed by the prediction module 211 in the lossless mode through entropy coding. can do. In this case, entropy coding may utilize a method of allocating the number of bits according to the frequency.

The entropy encoding module 215 may compress the image data 10 using Huffman coding. Alternatively, the entropy encoding module 215 may compress the image data 10 through exponential gollomb coding or gollomb rice coding. At this time, the entropy encoding module 215 can generate a table through the value of k, so that the image data 10 can be simply compressed.

The padding module 217 may perform padding on the image data 10 compressed by the entropy encoding module 215 in a lossless mode. Here, padding may mean adding meaningless data to fit a specific size. This will be explained in more detail later.

The padding module 217 can be activated in lossless mode as well as in lossy mode. In the lossy mode, when the image data 10 is compressed by the quantization module 213, it may be compressed more than a desired compression rate. In this case, even in the lossy mode, compressed data 20 may be converted through the padding module 217 and transmitted to the memory 300 .

The compression management module 218 controls the compression order of the first component and the second component of the image data 10 . Here, the image data 10 may be image data conforming to the YUV format.

In this case, the first mode selector 219 determines that the encoder 210 operates in a lossy mode, and accordingly, the image data 10 is compressed along the lossy path of FIG. 5 . That is, the compression management module 218 controls the compression order of the first component and the second component of the image data 10 so that the frame buffer compressor 200 uses a lossy compression algorithm to control the image data The case of performing compression for (10) is assumed.

Specifically, the image data 10 may include a first component and a second component. Here, the first component may include, for example, a luma component (corresponding to the “luminance signal” described above) including the Y component in the YUV format, and the second component may include, for example, the Cb and Cr components in the YUV format. Chroma component (corresponding to the “color difference signal” described above) may be included.

The compression management module 218 determines the compression order of the first component and the second component of the image data 10, and the frame buffer compressor 200 determines the compression order of the first component according to the compression order determined by the compression management module 218. and compresses the second component.

That is, when the compression management module 218 determines the compression order of the first component and the second component of the image data 10, the frame buffer compressor 200 performs the prediction module 211 of the encoder 210 according to the compression order. ), the quantization module 213 and the entropy encoding module 215 are used to compress the image data 10 .

Thereafter, the frame buffer compressor 200 generates a single bit stream by merging the compressed data for the first component and the compressed data for the second component, and writes the generated single bit stream to the memory 300. can do. Also, the frame buffer compressor 200 may read a single bit stream from the memory 300, decompress the read single bit stream, and provide the read single bit stream to the multimedia device 100.

Further details of the compression management module 218 performing such an operation will be described later with reference to FIGS. 9 to 15 .

FIG. 6 is a block diagram for explaining the decoder of FIG. 4 in detail.

Referring to FIG. 6 , the decoder 220 includes a second mode selector 229, an unpadding module 227, an entropy decoding module 225, an inverse quantization module 223, and a prediction compensation module 221.

The second mode selector 229 may determine whether the compressed data 20 stored in the memory 300 is losslessly compressed or losslessly compressed. At this time, the second mode selector 229 may determine which mode among the lossless mode and the lossy mode compresses the compressed data 20 through the presence or absence of the header. This will be explained in more detail later.

In the case of the lossless mode, the second mode selector 229 derives the compressed data 20 through the unpadding module 227, the entropy decoding module 225, and the prediction compensation module 221 along the lossless path (Lossless). can Conversely, in case of the lossy mode, the second mode selector 229 converts the compressed data 20 to the entropy decoding module 225, the inverse quantization module 223, and the prediction compensation module 221 along the loss path (Lossy). can induce

The unpadding module 227 may remove a padded portion of data padded by the padding module 217 of the encoder 210 .

The entropy decoding module 225 may decompress data compressed by the entropy encoding module 215 . The entropy decoding module 225 may perform decompression through Huffman coding, exponential Gollum coding, or Gollum-Rice coding. Since the compressed data 20 includes the k value, the entropy decoding module 225 may perform decoding using the k value.

The inverse quantization module 223 may decompress data compressed by the quantization module 213 . The inverse quantization module 223 can restore the compressed data 20 using the quantization coefficient determined by the quantization module 213, but cannot completely restore even a portion lost in the compression process. Thus, the inverse quantization module 223 can only be utilized in lossy mode.

The prediction compensation module 221 may restore data expressed by the prediction module 211 as prediction data and residual data. For example, the prediction compensation module 221 may convert the residual data representation of (253 (prediction), 1 (residual), 2 (residual)) to (253, 254, 255).

The prediction compensation module 221 may reconstruct prediction performed in units of pixels or units of blocks according to the prediction module 211 . Accordingly, the compressed data 20 may be restored or decompressed and transmitted to the multimedia device 100 .

The decompression management module 228 determines the compression order of the first component and the second component determined by the compression management module 218 described above with reference to FIG. 5 to compress the image data 10, the compressed data ( 20) can be properly reflected when decompressing.

The image data 10 of the image processing device according to some embodiments of the present invention may be YUV type data. At this time, the data of the YUV method may have a YUV 420 format and a YUV 422 format.

7 is a conceptual diagram for explaining three operation modes for YUV 420 format data of an image processing apparatus according to some embodiments of the present invention.

Referring to FIGS. 1 to 7 , the encoder 210 and the decoder 220 of the frame buffer compressor 200 may have three operation modes. The image data 10 in the YUV 420 format includes a luminance signal block (Y) having a size of 16 x 16, a first color difference signal block (Cb or U) and a second color difference signal block (Cr or V) each having a size of 8 x 8. can have Here, the size of each block means how many rows and columns the pixels are arranged in, and the size of 16 x 16 means the size of a block composed of a plurality of pixels having 16 rows and 16 columns.

The frame buffer compressor 200 may include three operation modes: ① Concatenation mode, ② Partial concatenation mode, and ③ Separation mode. These three modes relate to the compression format of data, and may be operation modes determined separately from the lossy mode and the lossless mode.

First, the connection mode (①) is an operation mode in which the luminance signal block (Y), the first color difference signal block (Cb), and the second color difference signal block (Cr) are all compressed and decompressed. That is, in the connection mode (①), as shown in FIG. 5, a compression unit block may be a block in which a luminance signal block (Y), a first color difference signal block (Cb), and a second color difference signal block (Cr) are combined. Accordingly, the size of the compression unit block may be 16 x 24.

In some connection modes (②), the luminance signal block (Y) is compressed and decompressed separately, but the first color difference signal block (Cb) and the second color difference signal block (Cr) can be combined and compressed and decompressed together. . Accordingly, the luminance signal block Y may have an original size of 16x16, and a block in which the first color difference signal block Cb and the second color difference signal block Cr are combined may have a size of 16x8.

Separation mode (③) is an operation mode in which the luminance signal block (Y), the first color difference signal block (Cb), and the second color difference signal block (Cr) are separately compressed and decompressed. At this time, in order to make the size of the compression and decompression unit blocks the same, the luminance signal block (Y) is maintained in its original size of 16 x 16, but the first color difference signal block (Cb) and the second color difference signal block ( Cr) can be enlarged to a size of 16 x 16.

Accordingly, if the number of luminance signal blocks Y is N, the number of first color difference signal blocks Cb and second color difference signal blocks Cr may be reduced to N/4, respectively.

When the frame buffer compressor 200 of the image processing device according to some embodiments of the present invention operates in the connection mode (①), all necessary data can be read through a single access request to the memory 300. In particular, when the multimedia device 100 requires data of the RGB method rather than the YUV method, it is advantageous to operate in the connection mode (①). This is because the luminance signal block (Y), the first color difference signal block (Cb), and the second color difference signal block (Cr) can be acquired at once in the connection mode (①), and in order to obtain RGB data, the luminance signal block (Y ), the first color difference signal block Cb and the second color difference signal block Cr are all required.

In contrast, the separation mode (③) may require lower hardware resources if the compression unit block is smaller than that of the concatenation mode (①). Accordingly, when the multimedia device 100 requires YUV data rather than RGB data, the separation mode (③) may be more advantageous.

Finally, some connection modes (②) are modes that compromise between connection mode (①) and separation mode (③), and require lower hardware resources compared to connection mode (①), and even when RGB data is required, memory ( 300) may be requested a smaller number of times (twice) than in the separation mode (③).

The first mode selector 219 may determine which of three modes to compress the image data 10 in: a connection mode (①), a partial connection mode (②), and a separation mode (③). The first mode selector 219 may receive from the multimedia apparatus 100 a signal indicating in which mode to operate among connection mode (①), partial connection mode (②), and disconnection mode (③).

The second mode selector 229 decompresses the compressed data 20 according to which mode the first mode selector 219 compresses in connection mode (①), partial connection mode (②), and separation mode (③). can

8 is a conceptual diagram illustrating three operation modes for YUV 422 format data of an image processing apparatus according to some embodiments of the present invention.

Referring to FIGS. 1 to 6 and 8 , the encoder 210 and decoder 220 of the frame buffer compressor 200 may have three operation modes even for the YUV 422 format. The image data 10 in the YUV 422 format includes a 16x16 luminance signal block (Y), a 16x8 size first color difference signal block (Cb or U) and a second color difference signal block (Cr or V), respectively. can have

In the connection mode (①), a compression unit block may be a block in which a luminance signal block (Y), a first color difference signal block (Cb), and a second color difference signal block (Cr) are combined. Accordingly, the size of a compression unit block may be 16 x 32.

In some connection modes (②), the luminance signal block (Y) is compressed and decompressed separately, but the first color difference signal block (Cb) and the second color difference signal block (Cr) can be combined and compressed and decompressed together. . Accordingly, the luminance signal block Y may have an original size of 16x16, and a block in which the first color difference signal block Cb and the second color difference signal block Cr are combined may have a size of 16x16. Accordingly, blocks in which the luminance signal block Y, the first color difference signal block Cb, and the second color difference signal block Cr are combined may have the same size.

Separation mode (③) is an operation mode in which the luminance signal block (Y), the first color difference signal block (Cb), and the second color difference signal block (Cr) are separately compressed and decompressed. At this time, in order to make the size of the compression and decompression unit blocks the same, the luminance signal block (Y) is maintained in its original size of 16 x 16, but the first color difference signal block (Cb) and the second color difference signal block ( Cr) can be enlarged to a size of 16 x 16.

Accordingly, if the number of luminance signal blocks Y is N, the number of first color difference signal blocks Cb and second color difference signal blocks Cr may be reduced to N/2, respectively.

Now, with reference to FIGS. 9 to 15 , operations of the image processing device described above will be described. An operation of the image processing device described below may be performed in the connection mode (①) described above with reference to FIGS. 7 and 8 .

9 to 11 are schematic diagrams for explaining an operation of an image processing apparatus for YUV 420 format data according to some embodiments of the present invention.

9 and 10, when the image data 10 conforms to the YUV 420 format, the target compression ratio for the image data 10 is 50%, and the color depth is 8 bits. is showing

Referring to FIG. 9 , the first component of the image data 10, that is, the luma component, corresponds to the Y plane 510Y of the image data 10, and the second component, that is, the chroma component of the image data 10 corresponds to the image data 10. Corresponds to the Cb plane (510Cb) and the Cr plane (510Cr) of data (10).

In the case of the Y plane 510Y, since the target compression ratio is 50% and the color depth is 8 bits, the luma component target bits can be calculated as follows.

Luma component target bits = 16 X 16 X 8 X 0.5 bits = 128 X 8 bits

In the case of the Cb plane 510Cb and the Cr plane 510Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows.

Cb plane component target bits = 8 X 8 X 8 X 0.5 bits = 32 X 8 bits

Cr plane component target bits = 8 X 8 X 8 X 0.5 bits = 32 X 8 bits

Accordingly, the chroma component target bits obtained by adding the Cb plane component target bits and the Cr plane component target bits become 64 X 8 bits.

When the luma component and the chroma component are compressed according to the calculated target bit, it is equivalent to compressing both the luma component and the chroma component at the same compression ratio of 50%.

The compressed bit stream 512 corresponding to the compression result may be formed as a single bit stream having, for example, the order of the Y component bit stream 512Y, the Cb component bit stream 512Cb, and the Cr component bit stream 512Cr. However, the scope of the present invention is not limited thereto, and the frame buffer compressor 200 may compress the first component (eg luma component) and the second component (eg chroma component) in an arbitrary order different from the compression order. The compressed bit stream 512 may be generated by merging the compressed data with the compressed data for the second component. That is, the order of the Y component bit stream 512Y, the Cb component bit stream 512Cb, and the Cr component bit stream 512Cr in the compressed bit stream 512 may be different from that shown in FIG. 9 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 generates a compressed bit stream 512 by interleaving and merging compressed data for a first component and compressed data for a second component. can That is, in the compressed bit stream 512, the Y component bit stream 512Y, the Cb component bit stream 512Cb, and the Cr component bit stream 512Cr are repeated for each pixel unit of the image data 10, for example, Y, Cb, Bit streams of Cr components may be generated in a mixed form in any order.

For example, the compressed bit stream 512 may include a Y component bit stream for a first pixel of image data 10, a Cb component bit stream for the first pixel, a Cr component bit stream for the first pixel, an image The Y component bit stream for the second pixel of the data 10, the Cb component bit stream for the second pixel, and the Cr component bit stream for the second pixel may be interleaved and merged in the following order, Y, Cb, The interleaving order of Cr components may also be determined in an arbitrary order.

In general, the human eye is more sensitive to changes in brightness than color. Therefore, it can be said that the importance of the luma component is higher than that of the chroma component in the image data 10 conforming to the YUV format.

However, when image data 10 conforming to the YUV format is compressed, since the pixel correlation of chroma components is higher than that of luma components, prediction is made more easily, and thus the compression efficiency of chroma components is improved. It comes out higher than the ingredients.

Therefore, in order to further increase the compression quality of the compressed data 20 obtained by compressing the image data 10, more bits are allocated to the luma component with low compression efficiency than the chroma component with high compression efficiency, so that the compression rate for the luma component is relatively increased. How to increase it can be considered.

Referring now to FIG. 10 , the first component of the image data 10, that is, the luma component, corresponds to the Y plane 520Y of the image data 10, and the second component, that is, the chroma component of the image data 10, Corresponds to the Cb plane 520Cb and the Cr plane 520Cr of the image data 10 .

In this embodiment, the compression management module 218 controls the compression order such that the frame buffer compressor 200 compresses the chroma component first and then the luma component. To this end, the compression management module 218 first calculates the chroma component target bits before calculating the luma component target bits.

In the case of the Cb plane 520Cb and the Cr plane 520Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows, respectively.

Cb plane component target bits = 8 X 8 X 8 X 0.5 bits = 32 X 8 bits

Cr plane component target bits = 8 X 8 X 8 X 0.5 bits = 32 X 8 bits

The compression management module 218 first performs compression on chroma components by allocating chroma component target bits before calculating luma component target bits. Specifically, the compression management module 218 performs compression on the chroma component by determining the QP value and the entropy k value so that the chroma component used bits are smaller than the chroma target bits and are closest to each other.

As a result, assume that 28 X 8 bits are used for compression of the Cb plane component and 30 X 8 bits are used for compression of the Cb plane component. That is, in this embodiment, chroma component use bits ((28 + 30) X 8 bits) are less than chroma component target bits ((32 +32) X 8 bits).

The compression management module 218 calculates luma component target bits for the luma component using the chroma component use bits of the compressed data for the chroma component.

The compression management module 218 can now compute the luma component target bits as follows.

Luma component target bits = total target bits - chroma component used bits = 192 X 8 bits - (28 + 30) X 8 bits = 132 X 8 bits

Here, the total target bits are (16 + 8) X 16 X 0.5 in the case of a 16 X 16 Y plane (520Y), an 8 X 8 Cb plane (520Cb), and an 8 X 8 Cr plane (520Cr). = The size of 192 multiplied by the color depth value of 8. And 0.5 means the target compression ratio.

The compression management module 218 assigns the calculated luma component target bits to perform compression on the luma component.

According to this embodiment, a compressed bit stream 512 comprising a 128-bit Y component bit stream 512Y, a 32-bit Cb component bit stream 512Cb, and a 32-bit Cr component bit stream 512Cr of FIG. Unlike , the compression result is a compressed bit stream 522 comprising a 28-bit Cb component bit stream 522Cb, a 30-bit Cr component bit stream 522Cr, and a 134-bit Y component bit stream 522Y.

As described above, the frame buffer compressor 200 compresses data for the first component and compresses the second component in an arbitrary order different from the compression order for the first component (eg, luma component) and the second component (eg, chroma component). A compressed bit stream 522 may be generated by merging compressed data for . That is, the order of the Y component bit stream 522Y, the Cb component bit stream 522Cb, and the Cr component bit stream 522Cr in the compressed bit stream 522 may be different from that shown in FIG. 10 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 may generate the compressed bit stream 522 by interleaving and merging the compressed data for the first component and the compressed data for the second component. That is, in the compressed bit stream 522, the Y component bit stream 522Y, the Cb component bit stream 522Cb, and the Cr component bit stream 522Cr are repeated for each pixel unit of the image data 10, for example, Y, Cb, Bit streams of Cr components can be generated in a mixed form in any order. In this way, within the same total target bits, more bits are allocated to luma components that have high importance and relatively low compression efficiency, and By allocating fewer bits to the undefined chroma components, the compression quality of the compressed data 20 obtained by compressing the image data 10 may be improved.

Next, referring to FIG. 11 , the first component of the image data 10, that is, the luma component, corresponds to the Y plane 530Y of the image data 10, and the second component of the image data 10, that is, the chroma component. The components correspond to the Cb plane 530Cb and the Cr plane 530Cr of the image data 10 .

In this embodiment, the compression management module 218 controls the compression order such that the frame buffer compressor 200 compresses the chroma component first and then the luma component. To this end, the compression management module 218 first calculates the chroma component target bits before calculating the luma component target bits. However, unlike the embodiment of FIG. 10 , the compression management module 218 may set the compression ratio of the chroma component to less than 50%, for example, 40.625% in advance.

Accordingly, in the case of the Cb plane 530Cb and the Cr plane 530Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows.

Cb plane component target bits = 8 X 8 X 8 X 0.40625 bits = 26 X 8 bits

Cr plane component target bits = 8 X 8 X 8 X 0.40625 bits = 26 X 8 bits

The compression management module 218 first performs compression on chroma components according to a preset compression rate, for example, 40.625%. Specifically, the compression management module 218 performs compression on chroma components by determining a QP value and an entropy k value according to the preset compression rate. As a result, 26 X 8 bits are used for compression of the Cb plane component, and 26 X 8 bits are used for compression of the Cb plane component.

The compression management module 218 can now compute the luma component target bits as follows.

Luma component target bits = Total target bits - Chroma component target bits according to preset compression rate = 192 X 8 bits - (26 + 26) X 8 bits = 140 X 8 bits

Here, the total target bits are (16 + 8) X 16 X 0.5 in the case of a 16 X 16 Y plane (530Y), an 8 X 8 Cb plane (530Cb), and an 8 X 8 Cr plane (530Cr). = The size of 192 multiplied by the color depth value of 8. And 0.5 means the target compression ratio.

The compression management module 218 assigns the calculated luma component target bits to perform compression on the luma component.

That is, in some embodiments of the present invention, including this embodiment, when the image data 10 conforms to the YUV 420 format, the chroma component target bits are calculated by the compression management module 218 as the total target bits / 3 X W ( However, W can be calculated as a positive real number of 1 or less). For example, the embodiment of FIG. 11 shows a case where the value of W is 0.40625.

According to this embodiment, a compressed bit stream 512 comprising a 128-bit Y component bit stream 512Y, a 32-bit Cb component bit stream 512Cb, and a 32-bit Cr component bit stream 512Cr of FIG. Unlike , the compression result is a compressed bit stream 532 comprising a 26-bit Cb component bit stream 532Cb, a 26-bit Cr component bit stream 532Cr, and a 140-bit Y component bit stream 522Y.

As described above, the frame buffer compressor 200 compresses data for the first component and compresses the second component in an arbitrary order different from the compression order for the first component (eg, luma component) and the second component (eg, chroma component). A compressed bit stream 532 may be generated by merging compressed data for . That is, the order of the Y component bit stream 532Y, the Cb component bit stream 532Cb, and the Cr component bit stream 532Cr in the compressed bit stream 532 may be different from that shown in FIG. 11 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 may generate the compressed bit stream 532 by interleaving and merging the compressed data for the first component and the compressed data for the second component. That is, in the compressed bit stream 532, the Y component bit stream 532Y, the Cb component bit stream 532Cb, and the Cr component bit stream 532Cr are repeated for each pixel unit of the image data 10, for example, Y, Cb, Bit streams of Cr components may be generated in a mixed form in any order.

In this way, within the same total target bits, more bits are allocated to luma components with high importance and relatively low compression efficiency, and fewer bits are allocated to chroma components with relatively low compression efficiency, thereby compressing the image data 10. The compression quality of the compressed data 20 can be improved.

12 to 14 are schematic diagrams for explaining an operation of an image processing apparatus for YUV 422 format data according to some embodiments of the present invention.

12 and 13 show a case where the image data 10 conforms to the YUV 420 format, the target compression ratio for the image data 10 is 50%, and the color depth is 8 bits.

Referring to FIG. 12 , a first component of the image data 10, that is, a luma component, corresponds to the Y plane 540Y of the image data 10, and a second component, that is, a chroma component of the image data 10 corresponds to an image Corresponds to the Cb plane (540Cb) and Cr plane (540Cr) of data (10).

In the case of the Y plane 540Y, since the target compression rate is 50% and the color depth is 8 bits, the luma component target bits can be calculated as follows.

Luma component target bits = 16 X 16 X 8 X 0.5 bits = 128 X 8 bits

In the case of the Cb plane 540Cb and the Cr plane 540Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows.

Cb plane component target bits = 16 X 8 X 8 X 0.5 bits = 64 X 8 bits

Cr plane component target bits = 16 X 8 X 8 X 0.5 bits = 64 X 8 bits

Accordingly, the chroma component target bits obtained by adding the Cb plane component target bits and the Cr plane component target bits become 128 X 8 bits.

When the luma component and the chroma component are compressed according to the calculated target bits, it is equivalent to compressing both the luma component and the chroma component at the same compression ratio of 50%.

The compressed bit stream 542 corresponding to the compression result may be formed as a single bit stream having, for example, the order of the Y component bit stream 542Y, the Cb component bit stream 542Cb, and the Cr component bit stream 542Cr. However, the scope of the present invention is not limited thereto, and the frame buffer compressor 200 may compress the first component (eg luma component) and the second component (eg chroma component) in an arbitrary order different from the compression order. The compressed bit stream 542 may be generated by merging the compressed data and the compressed data for the second component. That is, the order of the Y component bit stream 542Y, the Cb component bit stream 542Cb, and the Cr component bit stream 542Cr in the compressed bit stream 542 may be different from that shown in FIG. 12 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 may generate the compressed bit stream 542 by interleaving and merging the compressed data for the first component and the compressed data for the second component. That is, in the compressed bit stream 542, the Y component bit stream 542Y, the Cb component bit stream 542Cb, and the Cr component bit stream 542Cr are repeated for each pixel of the image data 10, for example, Y, Cb, Bit streams of Cr components may be generated in a mixed form in any order.

For example, the compressed bit stream 542 may include a Y component bit stream for a first pixel of image data 10, a Cb component bit stream for the first pixel, a Cr component bit stream for the first pixel, an image The Y component bit stream for the second pixel of the data 10, the Cb component bit stream for the second pixel, and the Cr component bit stream for the second pixel may be interleaved and merged in the following order, Y, Cb, The interleaving order of Cr components may also be determined in an arbitrary order.

Referring now to FIG. 13 , the first component of the image data 10, that is, the luma component, corresponds to the Y plane 550Y of the image data 10, and the second component of the image data 10, that is, the chroma component, Corresponds to the Cb plane (550Cb) and the Cr plane (550Cr) of the image data (10).

In this embodiment, the compression management module 218 controls the compression order such that the frame buffer compressor 200 compresses the chroma component first and then the luma component. To this end, the compression management module 218 first calculates the chroma component target bits before calculating the luma component target bits.

In the case of the Cb plane 520Cb and the Cr plane 520Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows, respectively.

Cb plane component target bits = 16 X 8 X 8 X 0.5 bits = 64 X 8 bits

Cr plane component target bits = 16 X 8 X 8 X 0.5 bits = 64 X 8 bits

The compression management module 218 first performs compression on chroma components by allocating chroma component target bits before calculating luma component target bits. Specifically, the compression management module 218 determines the QP value and the entropy k value so that the chroma component used bits are smaller than the chroma target bits and have the closest value, and performs compression on the chroma components.

As a result, assume that 62 X 8 bits are used for compression of the Cb plane component and 60 X 8 bits are used for compression of the Cb plane component. That is, in this embodiment, chroma component use bits ((62 + 60) X 8 bits) are less than chroma component target bits ((64 +64) X 8 bits).

The compression management module 218 calculates luma component target bits for the luma component using the chroma component use bits of the compressed data for the chroma component.

The compression management module 218 can now compute the luma component target bits as follows.

Luma component target bits = total target bits - chroma component used bits = 256 X 8 bits - (62 + 60) X 8 bits = 134 X 8 bits

Here, the total target bits are (16 + 8 + 8) X 16 in the case of a 16 X 16 Y plane (550Y), an 8 X 8 Cb plane (550Cb), and an 8 X 8 Cr plane (550Cr). This is the value obtained by multiplying the size of X 0.5 = 256 by the color depth value of 8. And 0.5 means the target compression ratio.

The compression management module 218 assigns the calculated luma component target bits to perform compression on the luma component.

According to this embodiment, a compressed bit stream 542 comprising a 128-bit Y component bit stream 542Y, a 64-bit Cb component bit stream 542Cb and a 64-bit Cr component bit stream 542Cr of FIG. 12 Unlike , the compression result is a compressed bit stream 552 comprising a 62-bit Cb component bit stream 552Cb, a 60-bit Cr component bit stream 552Cr, and a 134-bit Y component bit stream 552Y.

As described above, the frame buffer compressor 200 compresses data for the first component and compresses the second component in an arbitrary order different from the compression order for the first component (eg, luma component) and the second component (eg, chroma component). A compressed bit stream 552 may be generated by merging compressed data for . That is, the order of the Y component bit stream 552Y, the Cb component bit stream 552Cb, and the Cr component bit stream 552Cr in the compressed bit stream 552 may be different from that shown in FIG. 13 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 may generate the compressed bit stream 552 by interleaving and merging the compressed data for the first component and the compressed data for the second component. That is, in the compressed bit stream 552, the Y component bit stream 552Y, the Cb component bit stream 552Cb, and the Cr component bit stream 552Cr are repeated for each pixel unit of the image data 10, for example, Y, Cb, Bit streams of Cr components may be generated in a mixed form in any order.

In this way, within the same total target bits, more bits are allocated to luma components with high importance and relatively low compression efficiency, and fewer bits are allocated to chroma components with relatively low compression efficiency, thereby compressing the image data 10. The compression quality of the compressed data 20 can be improved.

Next, referring to FIG. 14 , the first component of the image data 10, that is, the luma component, corresponds to the Y plane 560Y of the image data 10, and the second component of the image data 10, that is, the chroma component. The components correspond to the Cb plane 560Cb and the Cr plane 560Cr of the image data 10 .

In this embodiment, the compression management module 218 controls the compression order such that the frame buffer compressor 200 compresses the chroma component first and then the luma component. To this end, the compression management module 218 first calculates the chroma component target bits before calculating the luma component target bits. However, unlike the embodiment of FIG. 13 , the compression management module 218 may set the compression rate of the chroma component to less than 50%, for example, 40.625% in advance.

Accordingly, in the case of the Cb plane 560Cb and the Cr plane 560Cr, the Cb plane component target bits and the Cr plane component target bits can be calculated as follows.

Cb plane component target bits = 16 X 8 X 8 X 0.40625 bits = 52 X 8 bits

Cr plane component target bits = 16 X 8 X 8 X 0.40625 bits = 52 X 8 bits

The compression management module 218 first performs compression on chroma components according to a preset compression rate, for example, 40.625%. Specifically, the compression management module 218 performs compression on chroma components by determining a QP value and an entropy k value according to the preset compression rate. As a result, 52 X 8 bits are used for compression of the Cb plane component, and 52 X 8 bits are used for compression of the Cb plane component.

The compression management module 218 can now compute the luma component target bits as follows.

Luma component target bits = Total target bits - Chroma component target bits according to preset compression rate = 256 X 8 bits - (52 + 52) X 8 bits = 152 X 8 bits

Here, the total target bits are (16 + 8 + 8) X 8 in the case of a 16 X 16 Y plane (560Y), an 8 X 8 Cb plane (560Cb), and an 8 X 8 Cr plane (560Cr). = 256 multiplied by the color depth value of 8. And 0.5 means the target compression ratio.

The compression management module 218 assigns the calculated luma component target bits to perform compression on the luma component.

That is, in some embodiments of the present invention, including this embodiment, when the image data 10 conforms to the YUV 422 format, the chroma component target bits are calculated by the compression management module 218 as total target bits / 2 X W ( However, W can be calculated as a positive real number of 1 or less). For example, the embodiment of FIG. 14 shows a case where the value of W is 0.5.

According to this embodiment, a compressed bit stream 542 comprising a 128-bit Y component bit stream 542Y, a 64-bit Cb component bit stream 542Cb and a 64-bit Cr component bit stream 542Cr of FIG. 12 , the compression result is a compressed bit stream 562 comprising a 52-bit Cb component bit stream 562Cb, a 52-bit Cr component bit stream 562Cr, and a 152-bit Y component bit stream 562Y.

As described above, the frame buffer compressor 200 compresses data for the first component and compresses the second component in an arbitrary order different from the compression order for the first component (eg, luma component) and the second component (eg, chroma component). A compressed bit stream 562 may be generated by merging compressed data for . That is, the order of the Y component bit stream 562Y, the Cb component bit stream 562Cb, and the Cr component bit stream 562Cr in the compressed bit stream 532 may be different from that shown in FIG. 14 .

Meanwhile, in some embodiments of the present invention, the frame buffer compressor 200 may generate the compressed bit stream 562 by interleaving and merging the compressed data for the first component and the compressed data for the second component. That is, in the compressed bit stream 532, the Y component bit stream 562Y, the Cb component bit stream 562Cb, and the Cr component bit stream 562Cr are repeated for each pixel unit of the image data 10, for example, Y, Cb, Bit streams of Cr components may be generated in a mixed form in any order.

In this way, within the same total target bits, more bits are allocated to luma components with high importance and relatively low compression efficiency, and fewer bits are allocated to chroma components with relatively low compression efficiency, thereby compressing the image data 10. The compression quality of the compressed data 20 can be improved.

15 is a flowchart illustrating an operating method of an image processing apparatus according to some embodiments of the present disclosure.

Referring to FIG. 15 , a method of operating an image processing apparatus according to some embodiments of the present disclosure includes calculating a target bit for a chroma component ( S1501 ).

Specifically, the image processing device calculates the total target bits based on the target compression rate for the image data 10 conforming to the YUV format before calculating the target bits for the chroma component, and then the Cb and Cr components of the YUV format. Chroma component target bits for compressing a chroma component including .

Further, the method includes allocating chroma component target bits to compress chroma components (S1503).

In addition, the method obtains a compressed bit for the chroma component, that is, a chroma component use bit of compressed data for the chroma component (S1505), and uses this to obtain a luma component including the Y component in the YUV format. and calculating luma component target bits for (S1507).

Further, the method includes allocating luma component target bits to compress the luma component (S1509).

Furthermore, the method further adds a dummy bit after the compressed data for the luma component when the sum of the luma component used bits and the chroma component used bits of the compressed data for the luma component is less than the total target bits. can include

Although the embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above embodiments and can be manufactured in a variety of different forms, and those skilled in the art in the art to which the present invention belongs A person will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

100: multimedia device
200: frame buffer compressor
300: memory

Claims (20)

A multimedia device for processing image data including a first component including a luma component and a second component including a chroma component;
a memory accessed by the multimedia device;
A Frame Buffer Compressor (FBC) configured to compress the image data to generate compressed data and store the compressed data in the memory;
The frame buffer compressor includes a compression management module for controlling a compression sequence of the first component and the second component of the image data;
The compression management module,
Calculate a chroma component target bit from a target compression ratio of the image data and the chroma component;
calculating a first luma component target bit from the target compression rate and the luma component;
assigning at least one of the chroma component target bits to the first luma component target bits to generate second luma component target bits;
and compressing the chroma component according to chroma component target bits remaining after the assignment, and compressing the luma component according to the second luma component target bits. According to claim 1,
The frame buffer compressor compresses the first component and the second component according to the compression order determined by the compression management module, and then merges the compressed data for the first component and the compressed data for the second component. An image processing device that generates a single bit stream using According to claim 2,
The frame buffer compressor merges compressed data for the first component and compressed data for the second component in an arbitrary order different from the compression order for the first component and the second component to form the single bit stream. An image processing device that generates According to claim 2,
The frame buffer compressor generates the single bit stream by interleaving and merging compressed data for the first component and compressed data for the second component. According to claim 2,
The frame buffer compressor writes the single bit stream to the memory. According to claim 1,
The image data is image data conforming to the YUV format,
The first component includes a luma component including a Y component in the YUV format,
The second component includes a chroma component including Cb and Cr components in the YUV format. According to claim 6,
The compression management module controls a compression sequence such that the frame buffer compressor first compresses the chroma component and then compresses the luma component. According to claim 7,
The compression management module,
An image processing device that calculates a total target bit based on the target compression rate. According to claim 8,
Chroma component used bits used to compress the chroma component are less than the chroma component target bits. According to claim 8,
When the image data conforms to the YUV 420 format, the chroma component target bits are:
An image processing device that is calculated with the total target bits / 3 XW (where W is a positive real number of 1 or less). According to claim 8,
When the image data conforms to the YUV 422 format, the chroma component target bits are:
An image processing device that is calculated as the total target bits / 2 XW (where W is a positive real number of 1 or less). According to claim 8,
The second luma component target bit is calculated by subtracting chroma component use bits used to compress the chroma component from the total target bits. a multimedia device that processes image data conforming to the YUV format; and
A Frame Buffer Compressor (FBC) for generating compressed data by performing compression on the image data and storing the compressed data in a memory;
The frame buffer compressor,
Compression of a chroma component including Cb and Cr components in the YUV format of the image data takes precedence over compression of a luma component including a Y component in the YUV format of the image data. Control the order of compression to be performed,
The frame buffer compressor,
Calculate a chroma component target bit from a target compression ratio of the image data and the chroma component,
calculating a first luma component target bit from the target compression rate and the luma component;
assigning at least one of the chroma component target bits to the first luma component target bits to generate second luma component target bits;
and compressing the chroma component according to chroma component target bits remaining after the assignment, and compressing the luma component according to the second luma component target bits. According to claim 13,
The frame buffer compressor,
An image processing device that calculates a total target bit based on the target compression rate. According to claim 14,
Chroma component used bits used to compress the chroma component are less than the chroma component target bits. According to claim 15,
The frame buffer compressor determines a QP value and an entropy k value such that the chroma component use bits are smaller than the chroma component target bits and have a closest value. According to claim 14,
When the image data conforms to the YUV 420 format, the chroma component target bits are:
An image processing device that is calculated with the total target bits / 3 XW (where W is a positive real number of 1 or less). According to claim 14,
When the image data conforms to the YUV 422 format, the chroma component target bits are:
An image processing device that is calculated as the total target bits / 2 XW (where W is a positive real number of 1 or less). According to claim 14,
The second luma component target bit is calculated by subtracting chroma component use bits used to compress the chroma component from the total target bits. According to claim 14,
The frame buffer compressor outputs a dummy after compressed data for the luma component when the sum of the luma component used bits used to compress the luma component and the chroma component used bits used to compress the chroma component is less than the total target bits. An image processing device that adds a dummy bit.

Images