Method and apparatus for decoding image based on skip mode

The present invention relates to a method for encoding and decoding mode information and a device thereof, and more specifically, to a method for encoding and decoding mode information of a video encoded according to a plurality of modes and a device thereof.

With the development of wireless network technology, interconnection between devices via wireless networks is becoming an issue. Many companies are striving to ensure interconnection technology between devices over wireless networks. In particular, recently, WiHD (wireless HD) standardization, which is an uncompressed HD (high-definition) interconnection technology that replaces HDMI (high definition multimedia interface), is in progress. According to WiHD, various devices such as TVs (televisions), home theaters, DVD (digital versatile disc) players, Blu-ray players, and camcorders are interconnected via wireless networks.

<p num="0003"> A technical problem to be solved by the present invention is to provide a method for encoding and decoding mode information of a video encoded according to a plurality of modes and an apparatus therefor, and a program for executing the method. A computer-readable recording medium is provided.</p>

<p num="0004"> The method for decoding the mode information of the current block of the video according to the embodiment of the present invention for solving the technical problem indicates whether or not the current block is encoded according to the first coding mode. 1 A step of decoding information, a step of determining whether or not the current block is encoded in the first coding mode based on the decoded first information, and a step of determining whether or not the current block is encoded in the first coding mode. Decoding the second information indicating which of the second and third coding modes the current block was encoded by the determination that it was not encoded according to the first coding mode. A step of determining a decoding mode used for decoding the current block based on at least one of the decoded first information and the decoded second information. The first coding mode comprises indicating that the current block is adjacent to the current block in the slice of the video and is identical to a second block encoded prior to the current block. It is characterized by.</p><p num="0005"> According to another embodiment of the present invention, the second coding mode is a coding mode that encodes the current block based on the discrete cosine transform, and the third coding mode is a pixel value. It may be a coding mode that encodes the current block based on the plurality of bit planes involved.</p><p num="0006"> According to still another embodiment of the invention, the step of decoding the first information is based on the third information indicating whether the slice contains blocks encoded according to the first coding mode. The step of selectively parsing the first information is included.</p><p num="0007"> According to still another embodiment of the invention, the step of selectively parsing the first information determines whether the current slice contains blocks encoded according to the first coding mode. A step of determining based on the information and a step of parsing the first information by determining that the current slice contains blocks encoded according to the first coding mode based on the third information. Including.</p><p num="0008"> According to still another embodiment of the present invention, the step of selectively parsing the first information determines whether or not the current slice contains blocks encoded according to the first coding mode. An informed determination and a fourth informed step of determining whether the current slice contains blocks encoded according to a second coding mode or blocks encoded according to a third coding mode. And, based on the third and fourth information, the current slice contains a block encoded according to the first coding mode, and the current slice contains a block encoded according to the second coding mode. Alternatively, it includes a step of parsing the first information by determining that it does not include blocks encoded according to a third coding mode.</p><p num="0009"> According to still another embodiment of the present invention, in the step of decoding the second information, the current block is encoded according to the first coding mode based on the decoded first information. By determining no, the current slice is selected based on fourth information indicating whether the current slice contains either blocks encoded according to the second coding mode and blocks encoded according to the third coding mode. Includes a step of parsing the second information.</p><p num="0010"> According to still another embodiment of the present invention, the step of selectively parsing the second information is a block in which the current slice is encoded according to the second coding mode and a code according to the third coding mode. As a result of the step of determining whether or not to include any of the encoded blocks based on the fourth information and the determination based on the fourth information, the current slice is encoded according to the second coding mode. Including both the block and the block encoded according to the third coding mode, the second indicating which mode the current block is encoded according to the second coding mode or the third coding mode. Includes the step of parsing information.</p><p num="0011"> According to yet another embodiment of the invention, the second coding mode discretely cosine transforms the pixel values of the first block and the significant bit (MSB) of the coefficient generated as a result of the discrete cosine. It is characterized in that it is a mode in which it is divided into a plurality of bit planes from to the least significant bit (LSB) and encoded in bit plane units.</p><p num="0012"> According to still another embodiment of the present invention, the third coding mode causes the pixel values of the first block to move from the bit plane of the most significant bit (MSB) to the bit plane of the least significant bit (LSB). The mode is characterized in that it is divided into a plurality of bit planes and encoded in bit plane units.</p><p num="0013"> The method for encoding the mode information of the current block of the video according to the embodiment of the present invention for solving the technical problem is, among the first coding mode, the second coding mode, and the third coding mode. A step of determining the coding mode of the current block, a step of encoding the first information indicating whether or not the current block is encoded according to the first coding mode, and a coding mode of the current block. However, by determining that it is not the first coding mode, the second information indicating whether the coding mode of the current block is one of the second coding mode and the third coding mode is encoded. In the first coding mode, including the step, the current block is adjacent to the current block in the slice of the video and is identical to a second block encoded prior to the current block. It is characterized by showing.</p><p num="0014"> The apparatus for decoding the mode information of the current block of the video according to the embodiment of the present invention for solving the technical problem is a first indicating whether or not the current block is encoded according to the first coding mode. The first information decoding unit that decodes the information and determines whether or not the current block is encoded in the first coding mode based on the decoded first information, and the current block , The second information indicating which of the second and third coding modes the current block was encoded by the determination that it was not encoded according to the first coding mode. The mode used for decoding the current block is determined based on the second information decoding unit to be decoded and the decoding result of at least one of the first information and the decoded second information. The first coding mode includes a mode determination unit, wherein the current block is adjacent to the current block in the slice of the video and is identical to a second block encoded prior to the current block. It is characterized by showing that there is.</p><p num="0015"> The apparatus for encoding the mode information of the current block of the video according to the embodiment of the present invention for solving the technical problem is the first coding mode, the second coding mode, and the third coding mode. A mode determination unit that determines the coding mode of the current block, a first information coding unit that encodes first information indicating whether or not the current block is encoded according to the first coding mode, and the above. The determination that the coding mode of the current block is not the first coding mode indicates whether the coding mode of the current block is one of the second coding mode and the third coding mode. In the first coding mode, the current block is adjacent to the current block in the slice of the video and is coded before the current block, including a second information coding unit that encodes two pieces of information. It is characterized by showing that it is the same as the second block that has been converted.</p><p num="0016"> In order to solve the technical problem, the present invention provides a computer-readable recording medium on which a program for executing the mode information coding method and the mode information decoding method is recorded.</p>

<p num="0017"> According to the present invention, the mode information can be encoded more efficiently by hierarchically encoding the information related to the coding mode of the video block.</p>

<figref num="1">It is a figure which illustrates the image coding apparatus by one Embodiment.</figref><figref num="2">It is a figure which illustrates the image coding unit by one Embodiment.</figref><figref num="3">It is a figure for demonstrating the method of determining the skip mode by one Embodiment.</figref><figref num="4">It is a figure which illustrates the video coding apparatus by another embodiment.</figref><figref num="5">It is a figure which illustrates the natural mode coding part by one Embodiment.</figref><figref num="6A">It is a figure which illustrates the graphic mode coding part by one Embodiment.</figref><figref num="6B">It is a figure which illustrates the bit plane base coding method by one Embodiment.</figref><figref num="7">It is a figure which illustrates the image coding apparatus by still another Embodiment.</figref><figref num="8">It is a figure which illustrates the video decoding apparatus by one Embodiment.</figref><figref num="9">It is a figure which illustrates the video decoding apparatus by another embodiment.</figref><figref num="10">It is a flowchart for demonstrating the video coding method by one Embodiment.</figref><figref num="11">It is a flowchart for demonstrating the video coding method by another Embodiment.</figref><figref num="12">It is a flowchart for demonstrating the image decoding method by one Embodiment.</figref><figref num="13">It is a figure which illustrates the mode information coding apparatus by one Embodiment.</figref><figref num="14">It is a flowchart for demonstrating the mode information coding method by one Embodiment.</figref><figref num="15">It is a flowchart for demonstrating the mode information coding method by another Embodiment.</figref><figref num="16">It is a flowchart for demonstrating the mode information coding method by still another Embodiment.</figref><figref num="17">It is a figure which illustrates the mode information decoding apparatus by one Embodiment.</figref><figref num="18">It is a flowchart for demonstrating the mode information decoding method by one Embodiment.</figref><figref num="19">It is a flowchart for demonstrating the mode information decoding method by another Embodiment.</figref><figref num="20">It is a flowchart for demonstrating the mode information decoding method by still another Embodiment.</figref>

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

FIG. 1 illustrates a video coding apparatus according to an embodiment of the present invention. Referring to FIG. 1, the video coding apparatus 100 according to one embodiment includes a mode determination unit 110 and a coding unit 120.

The mode determination unit 110 determines the mode currently used for coding the block. The technology related to the interconnection of devices via a wireless network aims to transmit and receive high-definition condensation of HD (high-definition) or higher via the wireless network. However, standardization is underway with a focus on small memory and low complexity to allow interconnection between diverse devices. Therefore, we are pursuing the lowest possible complexity in video coding, but unlike MPEG-1, MPEG-2, and MPEG-4 H.264 / MPEG-4 AVC (advanced video coding), compression is used. Do not use complex techniques to increase rates.

However, transmitting video pixel values without any compression requires a wireless network with a high transmission rate, which is also a factor that interferes with interconnection between various devices. Therefore, by encoding and decoding the video using three modes, skip mode, natural mode, and graphic mode, which will be described later, low complexity and appropriate level can be achieved. The compression ratio can be guaranteed.

The skip mode is a mode in which the current block is encoded based on whether or not the current block is the same as the block adjacent to the current block. The natural mode is a mode in which if the current block is a block related to a natural image, the current block is encoded by using a discrete cosine transform (DCT) and a bit plane division. The graphic mode is a mode in which the current block is encoded by using bit plane division if the current block is a block related to artificially generated video such as text. .. The skip mode, natural mode, and graphic mode will be described in detail later with reference to FIGS. 3 to 5.

The mode determination unit 110 determines which of the above-mentioned plurality of modes is used to encode the current block. First, the mode determination unit 110 determines whether the current block is the same as or similar to other blocks of the previously encoded current slice adjacent to the current block. The pixel value of the current block is compared to the pixel value of the previously encoded block of the current slice to determine if they are identical or similar. This will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 illustrates a video coding unit according to one embodiment. With reference to FIG. 2, the video coding apparatus 100 divides and encodes the video in slice units, block units, and bit plane units. The video coding apparatus 100 can currently divide the picture 210 into a plurality of slices 212,214,216 and a plurality of slices 212 to 216 having N in the vertical direction. The video encoder 100 divides each slice into blocks 220 of NxN size, and each NxN block 220 is further divided from the bit plane related to the most significant bit (MSB: most significant bit) to the least significant bit (LSB: least). It is divided into multiple bit planes up to the bit plane related to (significant bit). If the pixel value or discrete cosine coefficient of block 220 is represented by M bits, it is divided into M bit planes.

FIG. 3 is a diagram for explaining a method of determining the skip mode according to the embodiment. With reference to FIG. 3, currently picture 310 is divided into a plurality of slices, as described in connection with FIG. A case where the video coding apparatus 100 encodes the slice 320 illustrated in FIG. 3 will be described as an example.

In order to encode the current block 322 of the current slice 320, the mode determination unit 110 of the video coding device 100 indicates that the current block 322 is the same as the previously encoded block 324 adjacent to the current block. Or determine if they are similar. In general, the current block 322, which is spatially adjacent to an adjacent block, is likely to be the same as or similar to the adjacent block. Therefore, the mode determination unit 110 may be the same as or similar to the previously encoded block 324 of the current block 322, i.e., the adjacent block 324 illustrated to the left of the current block 322 in FIG. For example, it can be determined that the coding mode of the block 322 is currently the skip mode. The adjacent block 324 may be the block encoded immediately before the current block is encoded.

Decisions regarding whether block 322 and adjacent block 324 are the same or similar can be performed in a variety of ways. The cost is calculated based on the SAD (sum of absolute difference), MSE (mean square error), SNR (signal to noise ratio), maximum difference (max difference), etc. between the current block 322 and the adjacent block 324. , The calculated cost determines whether the current block 322 and the adjacent block 324 are the same or similar. The closer the SAD, MSE, and maximum difference is to "0", the more it can be determined that the current block 322 and the adjacent block 324 are the same or sufficiently similar.

The mode determination unit 110 determines that the coding mode of the current block 322 is the skip mode only when the current block 322 and the adjacent block 324 are exactly the same, and even if it is similar to the current block 322, it is currently It is also possible to determine that the coding mode of block 322 is the skip mode. In other words, even when the above-mentioned SAD, MSE, maximum difference, etc. is "0", or when the SAD, MSE, maximum difference, etc. are less than or equal to a predetermined critical value, the coding mode of block 322 is currently skipped. You can also decide that there is. Therefore, if the above-mentioned SAD, MSE, maximum difference, etc. are the same as or less than the predetermined critical value, it can be determined that the current block 322 and the adjacent block 324 are sufficiently similar. it can.

As a result of the mode determination unit 110 determining the same or similar condition between the current block and the adjacent block, if the coding mode of the current block is determined not to be the skip mode, the mode determination unit 110 encodes the current block. The mode is determined to be one of the natural mode and the graphic mode. If it is determined that the current block is related to a natural image, for example, an image that has not been artificially generated, then the coding mode of the current block is determined to be the natural mode. On the other hand, if it is determined that the current block is a block related to an artificially generated image such as text or computer graphics, the coding mode of the current block is determined to be the graphic mode.

There are no restrictions on the criteria for determining which mode the current block is encoded in, natural mode or graphic mode, and various algorithms are used to relate the current block to the artificially generated video. It can be determined whether it is a block or not. For example, in an artificial image, there is a high probability that the same pixel value will be distributed in a specific area. The pixel values of the current blocks are compared, and if the same pixel value is equal to or greater than a predetermined number, it can be determined that the block is related to an artificially generated image.

Further, according to another embodiment, after encoding the current block according to the natural mode and the graphic mode, respectively, the coding result is obtained by setting the natural mode or the graphic mode to the current block based on the RD cost (rate distortion cost). Although it can be determined that the mode is the coding mode, a detailed description of this will be described later with reference to FIG. 7.

If the mode determination unit 110 determines the mode currently used for coding the block, the coding unit encodes the current block according to the coding mode determined by the mode determination unit 110.

If the current block is the same as or similar to a previously encoded adjacent block and the current block's coding mode is determined to be skip mode, then instead of the current block's pixel value , Encodes information indicating that the block is currently encoded in skip mode. Information indicating that the current block is encoded according to skip mode, such as flag information, is encoded instead of the pixel value of the current block.

Instead of directly encoding the pixel value of the current block, the current block can be encoded with 1-bit flag information, which improves the compression ratio of the video. Further, in order to encode the current block according to the skip mode, only the block encoded immediately before the current block is referred to, so that the skip mode can be realized with low complexity.

If the current block is the same as or dissimilar to the previously encoded adjacent block and it is determined that the current block's coding mode is not skip mode, the coding unit 120 will Currently the block is coded according to natural mode or graphic mode. If the mode determination unit 110 determines that the coding mode of the current block is the natural mode, it encodes the current block according to the natural mode, and the mode determination unit 110 determines that the coding mode of the current block is the graphic mode. Once determined, it is encoded according to the graphic mode. The coding method in the natural mode and the graphic mode will be described in detail with reference to FIGS. 4 to 6.

FIG. 4 illustrates a video coding device according to another embodiment. Referring to FIG. 4, the video coding apparatus 400 according to the embodiment includes a mode determining unit 410, a natural mode coding unit 420, a graphic mode coding unit 430, and a mode information coding unit 440. The mode determination unit 410 corresponds to the mode determination unit 110 of FIG. 1, and the natural mode coding unit 420, the graphic mode coding unit 430, and the mode information coding unit 440 correspond to the coding unit 120 of FIG.

The mode determination unit 410 determines the coding mode of the current block. Of the skip mode, the natural mode, and the graphic mode, the mode currently used for coding the block can be determined.

If the mode determination unit 410 determines that the coding mode of the current block is the skip mode, the mode information coding unit 440 indicates that the current block is encoded according to the skip mode, for example, the current block. Instead of pixel values, it encodes flag information that indicates that the block is currently coded according to skip mode.

If the mode determination unit 410 determines that the coding mode of the current block is the natural mode, the natural mode coding unit 420 encodes the current block according to the natural mode. The block is currently subjected to the discrete cosine transform to generate the discrete cosine coefficient, the generated coefficient is separated into multiple bit planes, and each bit plane is coded using a bit plane basis coding method. To become. This will be described in detail with reference to FIG.

FIG. 5 illustrates a natural mode coding section according to one embodiment. Referring to FIG. 5, the natural mode coding unit 420 according to one embodiment includes a conversion unit 510, a bit plane selection unit 520, and a bit plane coding unit 530.

The transformant 510 performs a discrete cosine transform (DCT) on the current block to generate a discrete cosine transform coefficient. The Discrete Cosine Transform is only an example of how to convert the pixel values of a pixel domain to a frequency domain and generate a coefficient of the frequency domain, and it is the present invention that other methods are currently available for block conversion. It will be easy to understand if you are a person skilled in the art in the technical field to which

Of the discrete cosine transform coefficients generated by the conversion unit 510 by performing the discrete cosine transform of the current block, the bit string related to the coefficient of the DC (direct current) component is directly inserted into the bit stream. However, the coefficients of the AC (alternating current) component are encoded by the bit plane-based coding method.

The bit plane selection unit 520 separates the coefficients of the AC component into a plurality of bit planes. It is separated into a plurality of bit planes, from a bit plane composed of the most significant bit of the coefficient of the AC component to a bit plane composed of the least significant bit. The coefficient of the AC component of M bits is separated in bit units to generate M bit planes. The first bit plane composed of the most significant bit of the bit string related to the coefficient of the AC component is separated, and the second bit plane composed of the bits following the most significant bit is separated. Bitplane separation is repeated up to the least significant bit to separate M bitplanes.

If the bit plane selection unit 520 separates the plurality of bit planes, the bit plane coding unit 530 encodes each of the generated bit planes by using the bit plane base coding method. There is no limitation on the method for encoding the bit plane, and any bit plane-based coding method according to the prior art can be utilized in the present invention. Also, according to one embodiment, each bit plane is encoded using a bit mask. The area where one bit, which means each bit plane, exists is set by using the bit mast, and the bit plane base coding is performed only for the set area.

In relation to FIG. 5, the method of separating the DC coefficient and the AC coefficient and encoding them separately has been described above. However, the coding method described in connection with FIG. 5 is exemplary, and any method that currently utilizes blocks using the discrete cosine transform and the bitplane-based coding method is the natural mode coding unit. May be applied to 420.

With reference to FIG. 4 again, if the mode determination unit 410 determines that the coding mode of the current block is the graphic mode, the graphic mode coding unit 430 encodes the current block according to the graphic mode. The pixel value of the current block is separated into a plurality of bit planes, and each bit plane is encoded by using a bit plane-based coding method. This will be described in detail with reference to FIG. 6A.

FIG. 6A illustrates a graphic mode coding unit according to one embodiment. Referring to FIG. 6A, the graphic mode coding unit 430 according to one embodiment includes a bit plane selection unit 610 and a bit plane coding unit 620.

The bit plane selection unit 610 separates the pixel value of the current block into a plurality of bit planes. The pixel value of the P bit is separated in bit units, and P bit planes are generated from the bit plane composed of the most significant bit of the pixel value to the bit plane composed of the least significant bit of the pixel value.

If the bit plane selection unit 610 separates the plurality of bit planes, the bit plane coding unit 620 encodes each of the generated bit planes by using the bit plane base coding method.

FIG. 6B illustrates a bit plane substrate coding method according to one embodiment. Referring to FIG. 6B, the bit plane coding unit 620 groups the same bit values and encodes the bit plane. Taking the case where the block size is 4x4 and the pixel value is 8 bits as an example, the bit plane encoding unit 620 first displays the bit plane related to the most significant bit, bit 7, in FIG. 6B. Encode as shown. The bit plane related to bit 7 is coded by dividing it into a group 631 of "0" and a group 632 of "1". Since the bit planes related to the most significant bit 7 do not contain the same bits, "1" is first encoded, and "000111111111000" is encoded to indicate the division form.

The bit plane associated with bit 6 is based on a group of bits 7 and is encoded by whether or not each group is divided by different bit values. In the embodiment illustrated in FIG. 6B, neither the "0" group 631 nor the "1" group 632 is split, so that "00" indicates that the "0" group 631 is not split. Encode "01" to indicate that group 632 of "1" is not split.

In the bit plane related to bit 5, the group 632 of "1" of the bit plane related to bit 6 is divided into two groups 634 and 644. Therefore, "00" indicating that the group of "0" is not divided is first encoded, and "1" is encoded to indicate that the group 632 of "1" is divided. Then, "0000011111" is encoded to indicate the divided form of the group 632 of "1".

In the bit plane related to bit 4, the group 633 of "0" is divided again among the groups 633 and 634 generated by dividing the group 632 of "1". Therefore, "00" is first encoded to indicate that the group 631 of "0" is not split. Also, of the groups 633 and 634 generated by dividing the group 632 of "1", "1" is encoded to indicate that the group 633 of "0" is divided, and the group of "0" is used. "11100" is encoded to indicate the division form of 633. Then, "01" is encoded to indicate that the group 634 of "1" is not divided.

The bit plane coding unit 620 repeatedly applies the bit plane base coding method based on the bit group generated by grouping the same bit values as described above to the least significant bit, and encodes each bit plane.

Referring to FIG. 4 again, the mode information coding unit 440 encodes the information related to the mode currently used for coding the block. If the mode determination unit 410 determines that the coding mode of the current block is the skip mode, the mode information coding unit 440 indicates that the current block is encoded according to the skip mode, for example, the current block. Encodes flag information indicating that the code has been coded according to the skip mode.

If the mode determination unit 410 determines that the coding mode of the current block is the natural mode or the graphic mode, the mode information coding unit 440 indicates that the current block is encoded according to the natural mode, or a graphic. Encodes information that indicates that it was coded according to the mode. Similar to skip mode, it encodes flag information indicating that the block is currently encoded according to natural or graphic mode.

In addition, the mode information coding unit 440 encodes information indicating whether or not the current slice including the current block contains a block encoded according to the skip mode, the natural mode, or the graphic mode. Since it is the flag information related to the current slice, the flag information is encoded as the syntax element of the current slice.

FIG. 7 illustrates a video coding device according to still another embodiment. Referring to FIG. 7, the video coding apparatus 700 according to still another embodiment includes a skip mode determination unit 710, a natural mode coding unit 720, a graphic mode coding unit 730, a mode determination unit 740, and a mode information coding unit. Including 750.

The skip mode determination unit 710 and the mode determination unit 740 correspond to the mode determination unit 110 in FIG. 1, and the natural mode coding unit 720, the graphic mode coding unit 730, and the mode information coding unit 750 are encoded in FIG. Corresponds to part 120.

The skip mode determination unit 710 determines whether or not to encode the current block according to the skip mode. If the pixel value of the current block is compared to the pixel and value of a previously encoded block adjacent to the current block and it is determined that the current block and the adjacent block are the same or similar. , Determines that the current block coding mode is skip mode.

If the skip mode determination unit 710 determines that the coding mode of the current block is the skip mode, the mode information coding unit 750 encodes information indicating that the current block is encoded according to the skip mode. As described above, the flag information indicating that the block is currently encoded according to the skip mode is encoded by the mode information coding unit 750.

If the skip mode determination unit 710 determines that the current block coding mode is not the skip mode, the natural mode coding unit 720 and the graphic mode coding unit 730 encode the current block according to the natural mode and the graphic mode, respectively. To do.

The mode determination unit 740 compares the coding result of the natural mode coding unit 720 with the coding result of the graphic mode coding unit 730, and currently encodes the block according to the natural mode or encodes it according to the graphic mode. To decide.

The RD cost is calculated based on the result encoded according to the natural mode and the result encoded according to the graphic mode. The cost is calculated by cost = (rate) + (lambda) x (distortion), and the mode with the lowest cost is determined to be the current block coding mode. The "lambda" is set differently depending on the embodiment, and the "lambda" can be adjusted to change the selection ratio of the natural mode and the graphic mode.

If the mode determination unit 740 determines that the coding mode of the current block is the natural mode or the graphic mode, the mode information coding unit 750 determines the information related to the determined coding mode, for example, the current block is in the natural mode. The flag information indicating that the code is encoded according to the graphic mode or the flag information indicating that the code is encoded according to the graphic mode is encoded.

Further, as described above, the mode information coding unit 750 indicates whether or not the current slice includes a block encoded according to the skip mode, the natural mode, or the graphic mode in addition to the mode information related to each block. Is encoded.

FIG. 8 illustrates a video decoding apparatus according to one embodiment. Referring to FIG. 8, the video decoding apparatus 800 according to the embodiment includes a mode information decoding unit 810 and a decoding unit 820.

The mode information decoding unit 810 decodes the information related to the coding mode of the current block contained in the bit stream. It parses the bitstream and decodes information that indicates which of the skip mode, natural mode, and graphic mode the block is currently encoded according to.

The decoding unit 820 decodes the current block based on the mode information decoded by the mode information decoding unit 810. As a result of decoding the mode information, if the current block is encoded according to the skip mode, it is based on a block that is the same as or similar to the current block, for example, an adjacent previously decoded block. Restore the current block. The adjacent block may be the block that was decoded immediately before the decoding of the current block. Assuming that the current block is coded according to natural mode or graphic mode, the current block is restored by reversely performing the coding method described in connection with FIGS. 5 and 6A. This will be described in detail with reference to FIG.

FIG. 9 illustrates a video decoding apparatus according to still another embodiment. Referring to FIG. 9, the video decoding apparatus 900 according to still another embodiment includes a mode information decoding unit 910, a skip mode decoding unit 920, a natural mode decoding unit 930, and a graphic mode decoding unit 940. The mode information decoding unit 910 corresponds to the mode information decoding unit 810 of FIG. 8, and the skip mode decoding unit 920, the natural mode decoding unit 930, and the graphic mode decoding unit 940 correspond to the decoding unit 820 of FIG. Corresponds to.

Like the mode information decoding unit 810 of FIG. 9, the mode information decoding unit 910 decodes the information related to the coding mode of the current block included in the bit stream.

If the decoded mode information is the information related to the skip mode, the skip mode decoding unit 920 decodes the current block according to the skip mode. Restores the current block based on the previously decrypted block to which the current block is adjacent. You can restore the current block by copying the adjacent block as is.

If the decoded mode information is information related to the natural mode, the natural mode decoding unit 930 decodes the current block according to the natural mode. The natural mode decoding unit 930 first parses the coefficient of the DC component among the discrete cosine coefficients included in the bit stream. After that, a plurality of bit planes related to the coefficient of the AC component among the discrete cosine coefficients are restored by using the bit plane-based decoding method. Once the AC component coefficients are restored by combining the restored bit planes, the inverse discrete cosine transform is performed based on the restored AC component coefficients and the parsed DC component coefficients. As a result of the inverse discrete cosine transform, the current block is restored.

If the decoded mode information is information related to the graphic mode, the graphic mode decoding unit 940 decodes the current block according to the graphic mode. Using the bitplane-based decoding method, restore multiple bitplanes related to the pixel value of the current block. It then combines the restored bitplanes and restores the pixel values of the current block.

FIG. 10 is a flowchart for explaining a video coding method according to an embodiment. Referring to FIG. 10, at step 1010, the video coding apparatus 100 or 400 according to one embodiment determines whether or not the current block is currently encoded according to the skip mode. Skip mode encodes information indicating that the current block is encoded according to skip mode, instead of the pixel value of the current block, if the current block and adjacent blocks are the same or similar. It is a mode to do.

If in step 1010 it is determined that the current block's coding mode is not skip mode, then in step 1020 the video encoder 100 or 400 encodes the current block according to natural mode or according to graphic mode. Decide if you want to. As described in connection with the mode determination unit 110 of FIG. 1, it is determined whether the current block is a block related to a natural image or an artificially generated image, and the current block is made natural. Decide whether to code according to the mode or the graphic mode.

If in step 1020 it is determined that the current block is a block related to natural video, then in step 1030 the current block is encoded according to natural mode. At step 1030, the video encoder 100 or 400 currently encodes the block according to natural mode. The natural mode coding method has been described in relation to FIG.

If at step 1020 it is determined that the current block is related to an artificially generated video, then the current block is encoded according to the graphic mode. At step 1040, the video encoder 100 or 400 currently encodes the block according to the graphic mode. The graphic mode coding method has been described in relation to FIG. 6A.

At step 1050, the video coding device 100 or 400 encodes information relating to the coding mode currently used to code the block. If in step 1010 it is determined that the coding mode of the current block is skip mode, then instead of the pixel value of the current block, information indicating that the current block is coded according to skip mode is encoded. If at stage 1010 it is determined that the current block's coding mode is not skip mode, and at stage 1030 or 1040 the current block is coded according to natural or graphic mode, then the current block is coded according to natural mode. It encodes information indicating that it has been encoded, or information indicating that it has been encoded according to the graphic mode.

FIG. 11 is a flowchart for explaining a video coding method according to another embodiment. Referring to FIG. 11, at step 1110, the video coding apparatus 100 or 700 according to one embodiment determines whether or not the current block is currently encoded according to the skip mode. Stage 1110 corresponds to stage 1010 in FIG.

If at step 1110 it is determined that the current block coding mode is not skip mode, the video coding device 100 or 700 encodes the current block according to the natural mode and the graphic mode, respectively.

At step 1140, the video coding apparatus 100 or 700 compares the result of coding the current block according to the natural mode with the result of coding according to the graphic mode to determine the coding mode of the current block. The RD cost is calculated based on the result encoded according to the natural mode and the result encoded according to the graphic mode. As a result of the cost calculation, the mode with the lower cost is determined to be the current block coding mode.

At step 1150, the video coding device 100 or 700 encodes information relating to the coding mode currently used to code the block. If in step 1110 it is determined that the current block's coding mode is skip mode, then instead of the pixel value of the current block, information indicating that the current block is coded according to skip mode is encoded. If at stage 1110 it is determined that the current block's coding mode is not skip mode, and at stage 1140 it is determined that the current block's coding mode is natural or graphic mode, then the current block is in natural mode. The information indicating that the code was encoded according to the graphic mode or the information indicating that the code was encoded according to the graphic mode is encoded.

FIG. 12 is a flowchart for explaining a video decoding method according to an embodiment. Referring to FIG. 12, in step 1210, the video decoding apparatus 800 or 900 according to one embodiment decodes the information relating to the coding mode of the current block contained in the bitstream. It parses the bitstream and decodes the information related to the coding mode, which indicates which of the skip mode, the natural mode, and the graphic mode the block is currently coded according to.

At step 1220, the video decoder 800 or 900 decodes the current block based on the decoded mode information. In step 1210, if the current block is encoded according to skip mode as a result of decoding the mode information, then a block that is the same as or similar to the current block, that is, an adjacent previously decoded block. Restore the current block based on. Assuming that the current block is coded according to natural mode or graphic mode, the current block is restored by reversely performing the coding method described in connection with FIGS. 5 and 6A.

FIG. 13 illustrates a mode information coding device according to one embodiment. The mode information coding device shown in FIG. 13 corresponds to the mode information coding unit 440 of FIG. 4 and the mode information coding unit 750 of FIG. 7.

Referring to FIG. 13, the mode information coding apparatus 1300 according to one embodiment includes a first information coding unit 1310, a second information coding unit 1320, and a slice information coding unit 1330.

The first information coding unit 1310 encodes the first information indicating whether or not the current block is encoded according to the skip mode, for example, the flag information indicating whether or not the current block is encoded according to the skip mode. For example, if the current block is encoded according to the skip mode based on the determination of the coding mode of the mode determination units 110, 410 and 740, and the skip mode determination unit 710, the flag information is set to "1" and the current block is set. If is not encoded according to skip mode, the flag information can be set to "0".

According to another embodiment of the present invention, the first information coding unit 1310 selectively encodes the first information based on whether or not the slice currently contains a block encoded according to the skip mode. .. If the current slice does not contain blocks encoded according to the skip mode, then for every block of the current slice the information that the information relating to the skip mode has the same value is encoded. In other words, for every block of the current slice, it indicates whether or not it was coded according to the skip mode, and flag information having the same value of "0" is encoded. Therefore, if the current slice does not contain blocks encoded according to skip mode, there is no need to encode the first information for each block. Therefore, the first information coding unit 1310 encodes the first information for each block only when the current slice contains blocks encoded according to the skip mode.

According to yet another embodiment, if the current slice contains blocks encoded according to skip mode, but the current slice does not contain blocks encoded according to natural mode or graphic mode, then the current block is It is clear that it is coded according to the skip mode. Therefore, even if the current slice contains blocks encoded according to skip mode, the first information only if the current slice contains blocks encoded according to natural mode or encoded according to graphic mode. Is encoded.

If it is determined that the block is not currently encoded according to the skip mode, the second information coding unit 1320 indicates the second information indicating which of the natural mode and the graphic mode the current block is currently encoded. For example, as the information related to the natural mode and the graphic mode, it may be flag information for specifying the mode currently used for encoding the block among the natural mode and the graphic mode.

For example, if the current block is coded according to natural mode, the flag information can be set to "0", and if the current block is coded according to graphic mode, the flag information can be set to "1". it can. If the block is currently encoded according to the skip mode, the first information coding unit 1310 already encodes the information related to the skip mode, so that the second information coding unit 1320 is set to the natural mode and the graphic mode. There is no need to encode the relevant information.

Information indicating whether the current block is selectively encoded according to the second mode (for example, natural mode) or the third mode (for example, graphic mode) depending on whether or not the block is encoded according to the skip mode. In order to encode, the number of bits required to encode the information related to the mode can be reduced.

In other words, the Hoffman code encodes the mode-related information and more efficiently encodes the mode-related information. For example, if the current block is encoded according to skip mode, one bit of "1" can encode information indicating that it was encoded according to skip mode, and the current block is encoded according to natural mode. If it is converted, the information indicating that it is encoded according to the natural mode is encoded by 2 bits of "00". Also, if the current block is encoded according to the graphic mode, the 2 bits of "01" encode the information indicating that the block is encoded according to the graphic mode. In the information related to the natural mode and the information related to the graphic mode, the first bit "0" is the first information, which indicates that the block is not currently encoded according to the skip mode. The second bit, "0" and "1", is the second information, which indicates which of the natural mode and the graphic mode the block is currently encoded.

In addition, the second coding unit 1320 selectively encodes the second information depending on whether the current slice contains a block encoded according to the natural mode and a block encoded according to the graphic mode.

Only when the first coding unit 1320 determines that the coding mode of the current block is not the skip mode, the second coding unit 1320 encodes the second information. Therefore, the currently block coding mode is natural mode or graphic mode.

By the way, if the current slice contains only blocks encoded according to natural mode, then the current block is a block clearly encoded according to natural mode. Therefore, even if the second information is not encoded, the decoding side can know that the coding mode of the block is currently the natural mode. The same is true if the current slice contains only blocks encoded according to the graphic mode. Even if the second government coding unit 1320 does not encode the second information, the decoding side can know that the block is currently a block encoded according to the graphic mode.

However, if the current slice contains both blocks encoded according to natural mode and blocks encoded according to graphic mode, which mode is currently encoded according to natural mode or graphic mode? Is not known on the encoding side, so the second information coding unit 1320 encodes the second information for identifying the mode currently used for encoding the block among the natural mode and the graphic mode. ..

The slice information coding unit 1330 includes a third information indicating whether or not the slice currently contains a block encoded according to the skip mode, a block encoded according to the natural mode, and a block encoded according to the graphic mode. The fourth information indicating whether or not it is encoded is encoded. The fourth information can include flag information indicating whether or not the block encoded according to the natural mode is included, and flag information indicating whether or not the block encoded according to the graphic mode is included. As mentioned above, whether the first information coding unit 1310 and the second information coding unit 1320 currently include blocks encoded according to skip mode and whether the slice contains blocks encoded according to natural mode. The first and second information are selectively encoded depending on whether or not the block is encoded according to the graphic mode. Therefore, the slice information coding unit 1330 encodes the third information and the fourth information, and even if the first information and the second information are not encoded, the decoding side can specify the coding mode of the current block. ..

FIG. 14 is a flowchart for explaining the mode information coding method according to the embodiment. Referring to FIG. 14, at step 1410, the mode information coding apparatus 1300 determines the coding mode of the current block. The mode currently used for coding the block is determined via the mode determination units 110, 410 and 740 and the skip mode determination unit 710.

At step 1420, the mode information coding device 1300 encodes the information related to the skip mode. Encodes the first information that indicates whether the block is currently encoded according to skip mode. If the current block coding mode is skip mode, the flag information can be set to "1", and if the current block coding mode is not skip mode, the flag information can be set to "0".

At step 1430, the mode information encoder 1300 determines whether the current block coding mode is skip mode. If the current block coding mode is skip mode, step 1450 encodes a third piece of information indicating whether the current slice contains blocks encoded according to skip mode. The flag information indicating whether or not the slice currently contains a block encoded according to the skip mode can be set to "1".

If the current block's coding mode is not skip mode, step 1440 encodes a second piece of information indicating which of the natural and graphic modes the current block was coded according to. If the current block coding mode is natural mode, set the flag information to "0", and if the current block coding mode is graphic mode, set the flag information to "1". Can be done.

Once the second information has been coded in step 1440, the fourth information is encoded in step 1450 to indicate whether the slice now contains blocks encoded according to natural and graphic modes. It encodes flag information indicating whether the current slice contains blocks encoded according to natural mode and flag information indicating whether it contains blocks encoded according to graphic mode.

FIG. 15 is a flowchart for explaining a mode information coding method according to another embodiment. Referring to FIG. 15, at step 1510, the mode information coding apparatus 1300 determines the coding mode of the current block. Corresponds to stage 1410 in FIG.

At step 1520, the mode information encoder 1300 determines whether the slice now contains blocks encoded according to skip mode. If the current slice does not contain a block encoded according to skip mode, it is not necessary to encode the first information indicating whether or not the current block is encoded according to skip mode.

If at step 1520 it is determined that the current slice contains a block encoded according to skip mode, then at step 1530 the mode information encoder 1300 indicates whether the current block is currently encoded according to skip mode. 1 Encode the information. If the current block is encoded according to skip mode, the flag information can be set to "1", and if it is not encoded according to skip mode, the flag information can be set to "0".

At step 1540, the mode information encoder 1300 determines whether the block is currently encoded according to skip mode. If the current block is encoded according to skip mode, move to step 1570 because there is no need to encode information indicating whether the current block is encoded according to natural or graphic mode.

At step 1550, the mode information encoder determines whether the current slice contains both blocks encoded according to natural mode and blocks encoded according to graphic mode. If the current slice contains only blocks encoded according to natural mode, then it is clear that the current block is also a block encoded according to natural mode, so that the current block is of natural mode and graphic mode. Since it is not necessary to encode the second information indicating which mode was encoded, move to step 1570. Also, if the current slice contains only blocks encoded according to the graphic mode, then it is clear that the current block is also a block encoded according to the graphic mode, so there is no need to encode the second information. So move to stage 1570.

At step 1560, the mode information encoder encodes a second piece of information indicating which of the natural and graphic modes the block is currently encoded according to. Set the flag information to "0" if the current block is encoded according to natural mode, and set it to "1" if the current block is encoded according to graphic mode.

At step 1570, the mode information coding device indicates whether the current slice contains blocks encoded according to skip mode; and according to the blocks whose current slice is encoded according to natural mode, and graphic mode. Encode the fourth piece of information; whether or not it contains a coded block. The fourth information includes flag information indicating whether the current slice contains blocks encoded according to natural mode, and flag information indicating whether the current slice contains blocks encoded according to graphic mode. Can include.

FIG. 16 is a flowchart for explaining a method of encoding mode information according to still another embodiment. Comparing the embodiment illustrated in FIG. 16 with the embodiment illustrated in FIG. 15, it differs where step 1625 is added. The other stages of stages 1610 to 1670 correspond to stages 1510 to 1570 of FIG. 15, respectively. According to the embodiment illustrated in FIG. 15, the first information was encoded even when the current slice contained only blocks encoded according to skip mode. However, according to the embodiment illustrated in FIG. 16, if step 1625 is added and the current slice contains only blocks encoded according to skip mode, it moves to step 1670 and does not encode the first information. ..

Table 1 below summarizes the mode information encoded by FIG.

<tables num="1"><img id="000002" he="120" wi="158" file="JP5775083B2_D0001.tif" img-format="tif" img-content="drawing" /></tables> The "skip_mode_used" field is flag information indicating whether or not the slice currently contains a block encoded according to the skip mode, and corresponds to the above-mentioned third information. The "nat_mode_used" field is flag information indicating whether the current slice contains blocks encoded according to natural mode. The "graphic_mode_used" field is flag information indicating whether or not the slice currently contains blocks encoded according to the graphic mode. The "nat_mode_used" field and the "graphic_mode_used" field correspond to the fourth information described above. The first information is flag information indicating whether or not the current block is encoded according to the skip mode, and the second information indicates whether the current block is encoded according to the natural mode or the graphic mode. Flag information.

FIG. 17 illustrates a mode information decoding apparatus according to one embodiment. The mode information coding device illustrated in FIG. 17 corresponds to the mode information decoding unit 810 of FIG. 8 and the mode information decoding unit 910 of FIG. Referring to FIG. 17, the mode information decoding apparatus 1700 according to one embodiment includes a slice information decoding unit 1710, a first information decoding unit 1720, a second information coding unit 1730, and a mode determination unit 1740.

The slice information decoding unit 1710 is encoded from the bitstream according to the third information indicating whether or not the current slice contains a block encoded according to the skip mode, and the block encoded according to the natural mode and the graphic mode. Parsing the fourth information indicating whether the block is included. The fourth information can include flag information indicating that the block is encoded according to the natural mode and flag information indicating whether or not the block is encoded according to the graphic mode.

The first information decoding unit 1720 parses the first information indicating whether or not the block is currently encoded according to the skip mode. The first information may be flag information indicating whether or not the block is currently encoded according to the skip mode. If the current block is encoded according to skip mode, the flag information is "1", and if the current block is not encoded according to skip mode, the flag information is "0". You may.

According to another embodiment of the invention, the first information decoding unit 1720 selectively encodes the first information based on whether the slice currently contains blocks encoded according to skip mode. To do. If the current slice does not contain blocks encoded according to skip mode, then it is clear that every block of the current slice is not encoded according to skip mode, and the mode information encoder 1300 is the first information. Is not encoded. Therefore, if the current slice does not contain blocks encoded according to skip mode, there is no need to parse the first information for each block. Therefore, the first information decoding unit 1710 encodes the first information for each block only when the current slice contains blocks encoded according to the skip mode.

According to still another embodiment, even if the current slice contains a block encoded according to the skip mode, the mode information coding apparatus 1300 currently uses the block whose slice is encoded according to the natural mode, or the graphic mode. The first information is encoded only if it contains blocks encoded according to. The first information decoding unit 1720 refers to the fourth information decoded by the slice information decoding unit 1710, and currently slices a block encoded according to the natural mode or a block encoded according to the graphic mode. The first information can be parsed only if it is included.

If the second information decoding unit 1720 determines that the block is not currently encoded according to the skip mode, the second information decoding unit 1720 indicates which of the natural mode and the graphic mode the current block is encoded. Parsing information. The second information may be flag information for identifying the mode currently used for encoding the block among the natural mode and the graphic mode. If the current block is encoded according to the skip mode, the first information decoding unit 1710 has already parsed the information related to the skip mode, and the mode currently used for decoding the block is the skip mode. Therefore, it is not necessary to parsing the information related to the natural mode and the graphic mode.

Further, the second information decoding unit 1320 refers to the fourth information decoded by the slice information decoding unit 1710, and selectively encodes the second information. If the current slice contains only blocks encoded according to natural mode, it is clear that the current block is a block encoded according to natural mode, and the mode information encoder 1300 encodes the second information. Therefore, it is not necessary for the second information decoding unit 1320 to parsing the second information. Also, if the current slice contains only blocks encoded according to the graphic mode, it is clear that the current block is a block encoded according to the graphic mode, and the mode information encoder 1300 provides second information. Is not encoded, so that the second information decoding unit 1320 does not need to parsing the second information.

In short, the second information decoding unit 1320 refers to the fourth information, and as a result, the second information is obtained only when the current slice contains both the block encoded according to the natural mode and the block encoded according to the graphic mode. Parsing.

The mode determination unit 1740 currently blocks the current block based on at least one of the first information decoded by the first information decoding unit 1720 and the second information decoded by the second information decoding unit 1730. Determine the mode used for decryption. Based on the first information, it is first determined whether the mode currently used for decoding the block is skip mode, and if it is not skip mode, which of the natural mode and the graphic mode is currently used. Decide whether to decrypt the block.

FIG. 18 is a flowchart for explaining a mode information decoding method according to the embodiment. Referring to FIG. 18, at step 1810, the mode information decoding apparatus 1700 decodes the first information indicating whether or not the current block is currently encoded according to the skip mode. Parsing the first information in the bitstream.

At step 1820, the mode information decoder 1700 determines whether the current block is currently encoded according to skip mode, based on the first information decoded in step 1820. If the current block is encoded according to skip mode, it moves to stage 1840 and determines that the mode currently used to decode the block is skip mode.

If in step 1820 it is determined that the block is not currently coded according to skip mode, then in step 1830 the mode information decoder 1700 encodes the block according to either the natural mode or the graphic mode coding mode. Decrypt the second information indicating whether it has been converted. Parsing the second information in the bitstream. Then, based on the decrypted second information, in step 1840, the mode currently used for decoding the block is determined to be the natural mode or the graphic mode.

FIG. 19 is a flowchart for explaining a mode information decoding method according to another embodiment. Referring to FIG. 19, at step 1910, the mode information decoder 1700 provides a third piece of information indicating whether the mode information encoder currently contains blocks whose slices are encoded according to skip mode, and now Decoding the fourth information indicating whether the slice contains blocks encoded according to natural mode and blocks encoded according to graphic mode. Parsing the 3rd and 4th information with a bitstream.

At step 1920, mode information decoder 1700 determines whether the slice now contains blocks encoded according to skip mode. Based on the third information decoded in step 1910, it is determined whether the current slice contains blocks encoded according to skip mode. If the current slice does not contain a block encoded according to skip mode, then there is no need to parse the current block with the first information indicating whether it was encoded according to skip mode.

If at step 1920 it is determined that the current slice contains blocks encoded according to skip mode, then at stage 1930 mode information decoder 1700 indicates whether the current block is currently encoded according to skip mode. 1 Parsing information.

At step 1940, the mode information decoder 1700 determines whether the block is currently encoded according to skip mode. At step 1930, it is determined whether the current block is currently encoded according to skip mode, based on the first parsing information. If the current block is encoded according to the skip mode, it is necessary to parsing the information indicating which of the natural mode and the graphic mode the current block is encoded according to, so that the process is moved to stage 1970.

At step 1950, the mode information decoder 1700 determines whether the current slice contains both blocks encoded according to natural mode and blocks encoded according to graphic mode. Determined based on the fourth information decoded in step 1910. If the current slice contains only blocks encoded according to natural mode, then it is clear that the current block is also a block encoded according to natural mode, so that the current block is of natural mode and graphic mode. Since it is not necessary to parsing the second information indicating which mode was encoded, move to stage 1970. Also, if the current slice contains only blocks encoded according to the graphic mode, then it is clear that the current block is also a block encoded according to the graphic mode, so there is no need to parsing the second information. , Move to stage 1970.

At step 1960, the mode information decoder 1700 parges a second piece of information indicating which of the natural and graphic modes the block is currently encoded according to.

In stage 1970, the mode currently used for decoding the block is determined based on at least one of the first and second information parsed in stages 1930 and 1960.

FIG. 20 is a flowchart for explaining a method of encoding mode information according to still another embodiment. FIG. 20 illustrates a mode information decoding method corresponding to the mode information coding method of FIG. Comparing the embodiment illustrated in FIG. 20 with the embodiment illustrated in FIG. 19 is different where stage 2030 is added. Stages 2010 to 2070 correspond to stages 1910 to 1970, respectively, in FIG. According to the embodiment illustrated in FIG. 19, the first information was also parsed when the current slice contained only blocks encoded according to skip mode. However, according to the embodiment illustrated in FIG. 20, if step 2025 is added and the current slice contains only blocks encoded according to skip mode, go to step 2070 and do not parsing the first information.

As described above, even if the present invention is described with reference to limited embodiments and drawings, the present invention is not limited to the above-described embodiments, and those skilled in the art are skilled in the art to which the present invention belongs. If so, various modifications and modifications would be possible from such a description. Therefore, the idea of the present invention is grasped only by the scope of claims, and any modification that is equal to or equivalent to it belongs to the category of the idea of the present invention. Further, the system according to the present invention can be embodied as a computer-readable code on a computer-readable recording medium.

For example, a video coding device and a video decoding device according to an exemplary embodiment of the present invention are coupled to each unit of a device as shown in FIGS. 1, 4, 7, 8, and 9. The bus can include at least one processor coupled to the bus. It is also coupled to the bus to store instructions, received messages or generated messages, execute instructions as described above, and couple to at least one processor to control the operation of the device. Can include memory.

Also, computer-readable recording media include all types of recording devices in which data readable by computer systems is stored. Examples of recording media include ROM (read-only memory), RAM (random-access memory), CD-ROM, magnetic tape, floppy (registered trademark) disk, and optical data storage device. Further, the computer-readable recording medium is distributed to the computer system connected to the network, and the computer-readable code is stored and executed in a distributed manner. Also, one embodiment may include a computer-readable transmission medium, such as a carrier wave, for transmission over a network.