KR20080020314A - Scalable video encoding apparatus and method and scalable video decoding apparatus and method - Google Patents

Abstract

A scalable video encoding apparatus and a scalable video decoding apparatus are provided to perform decoding using a base layer bitstream acquired from a scalable bitstream in an existing base decoder and perform decoding using the base layer bitstream and an extension layer bitstream included in the scalable bitstream in an improved decoder, thereby enabling an improved video codec and an existing video codec to coexist with each other. A scalable video encoding apparatus comprises a base layer encoding unit(510), an extension layer encoding unit(530), and a bitstream combining unit(550). The base layer encoding unit generates a base layer bitstream supporting a bit depth in correspondence to a base bit by encoding video data. The extension layer encoding unit generates an extension layer bitstream supporting a bit depth in correspondence to an extension bit by encoding the video data. The bitstream combining unit generates a scalable bitstream by combining the base layer bitstream and the extension layer bitstream each other.

Description

Scalable video encoding apparatus and method and scalable video decoding apparatus and method

1 is a view for explaining the concept of a scalable video encoding apparatus and a scalable video decoding apparatus according to the present invention;

2 is a diagram illustrating an example of a syntax of a scalable bitstream obtained from a scalable video encoding apparatus according to the present invention;

3A to 3D are diagrams showing examples of information included in each base layer or extension layer shown in FIG. 2;

4 is a view showing an example of a start code as a section for loading an extended layer identifier in the scalable video encoding apparatus according to the present invention;

5 is a block diagram showing a configuration according to a first embodiment of a scalable video encoding apparatus according to the present invention;

6 is a block diagram showing a configuration according to a first embodiment of a scalable video decoding apparatus according to the present invention;

7 is a block diagram showing a configuration according to a second embodiment of a scalable video encoding apparatus according to the present invention;

8 is a block diagram showing a configuration according to a second embodiment of a scalable video decoding apparatus according to the present invention;

9 is a block diagram showing a configuration according to a third embodiment of a scalable video encoding apparatus according to the present invention; and

10 is a block diagram showing a configuration according to a third embodiment of a scalable video decoding apparatus according to the present invention.

The present invention relates to a scalable video encoding apparatus and method and a video decoding apparatus and method, and more particularly, to a scalable video encoding apparatus capable of decoding even if at least one of bit-depth or video format is changed; The present invention relates to a method and a scalable video decoding apparatus and method.

In a typical video codec, for example, the bit depth of a basic encoder such as a VC-1 encoder is changed from a basic bit, i.e., 8 bits to an extended bit, for example 10 bits, or a video format of a basic encoder such as a VC-1 encoder. If we change from 4: 2: 0 to simply 4: 2: 2 or 4: 4: 4, the VC-1 decoder generates a bitstream generated from an enhanced encoder with extended bit depth or an improved encoder with changed video format. It is impossible to read and play it. In recent years, forward compatibility allows the VC-1 decoder and other advanced decoders to recover not only such fixed bit depths or fixed image formats, but also bitstreams encoded at various bit depths or various image formats. There is a great need to develop a video codec that is guaranteed.

That is, a new video codec that does not guarantee forward compatibility cannot support a terminal having only an existing basic video codec, and thus content reuse between terminals having different specifications is not possible. In addition, there is a disadvantage that it takes a long time before the new video codec takes place in the market because it has to overcome the already established video codec market.

SUMMARY An aspect of the present invention provides a scalable video encoding apparatus capable of encoding a bit depth by changing from a basic bit to an extended bit, or by changing a first video format to a second or third video format and encoding the same. To provide a method.

Another technical problem to be solved by the present invention is to decode a bitstream obtained by changing a bit depth from a basic bit to an extended bit, or by changing a first video format to a second or third video format. The present invention provides a scalable video decoding apparatus and method.

In order to achieve the above technical problem, the scalable video encoding apparatus according to the present invention generates a scalable bitstream supporting a base bit and a bit depth of an extension bit different from the base bit. A base layer encoder for generating a base layer bitstream including data obtained by encoding according to bit depths, an extended quantization level, and a basic quantization coefficient; An extension layer encoder for generating an extension layer bitstream including data obtained by encoding the image data according to bit depths of the extension bits, and an extension index for compensating a difference between the extension bits and the basic bits; And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream.

In order to achieve the above technical problem, the scalable video encoding method according to the present invention generates a scalable bitstream supporting a base bit and a bit depth of an extension bit different from the base bit, wherein the scalable bitstream is image data. A base layer bitstream including data, an extended quantization level, and a basic quantization coefficient obtained by encoding H according to the bit depth of the basic bit; And an extension layer bitstream including data obtained by encoding the image data according to the bit depth of the extension bit, and an extension index for compensating for the difference between the extension bit and the basic bit.

According to an aspect of the present invention, a scalable video encoding apparatus includes a first video format and a scalable video encoding apparatus for generating a scalable bitstream that supports a second video format different from the first video format. And a base layer for generating a base layer bitstream including a first luminance block bitstream obtained by encoding the luminance block of the second image format and a chrominance block bitstream obtained by encoding the chrominance block of the first image format. Encoding means; And a second luminance block bitstream obtained by encoding the luminance block of the second image format, and a chrominance difference image bitstream obtained by encoding the color difference image between the restored color difference block and the original color difference block of the second image format. Enhancement layer encoding means for generating an enhancement layer bitstream; And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream.

According to an aspect of the present invention, there is provided a scalable video encoding method in which a luminance block bitstream obtained by encoding a luminance block of the second image format and a first color difference obtained by encoding a color difference block of the first image format. A base layer bitstream consisting of a block bitstream; And an enhancement layer bitstream including the luminance block bitstream and a second chrominance block bitstream obtained by encoding a color difference image between the restored color difference block of the second image format and the original color difference block.

According to an aspect of the present invention, there is provided a scalable video encoding apparatus according to an embodiment of the present invention, including a bit depth of a base bit and an extension bit different from the base bit, and a first video format and a second video format different from the first video format. A scalable video encoding apparatus for generating a scalable bitstream that supports the data, comprising: data obtained by encoding a luminance block of the second video format according to the bit depth of the basic bit, an extended quantization level, and a basic quantization coefficient Base layer encoding means for generating a base layer bitstream comprising a first luminance block bitstream and a chrominance block bitstream obtained by encoding a chrominance block of the first video format; A second luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the bit depth of the extension bit, and an extension index for compensating a difference between the extension bit and the basic bit; Enhancement layer encoding means for generating an enhancement layer bitstream comprising a color difference block bitstream obtained by encoding a color difference image between the restored color difference block of the second image format and the original color difference block; And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream.

In order to achieve the above technical problem, the scalable video encoding method according to the present invention includes a bit depth of a base bit and an extension bit different from the base bit, a first video format, and a second video format different from the first video format. Generating a scalable bitstream that supports the data stream, wherein the scalable bitstream includes data obtained by encoding the luminance block of the second image format according to the bit depth of the basic bit, an extended quantization level, and a basic quantization coefficient. A base layer bitstream comprising a luminance block bitstream and a chrominance block bitstream obtained by encoding the chrominance block of the first video format; And a second luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the bit depth of the extension bit, and an expansion index for compensating for the difference between the extension bit and the basic bit. And an enhancement layer bitstream including a color difference image bit stream obtained by encoding a color difference image between the restored color difference block of the second image format and the original color difference block.

According to an aspect of the present invention, there is provided a scalable video decoding apparatus including: a bitstream analyzer for analyzing a received bitstream to determine whether an extension layer identifier is included; When the bitstream does not include the enhancement layer identifier, a base layer decoding is performed to decode a base layer bitstream of the bitstream to generate a basic reconstructed image, and when the bitstream includes the enhancement layer identifier, to provide decoded base layer information. part; An enhancement layer decoder for decoding an enhancement layer bitstream of the bitstream when the bitstream includes the enhancement layer identifier; And a bit depth recovery unit for restoring a bit depth of the enhancement layer bitstream using the decoded base layer information.

According to an aspect of the present invention, there is provided a scalable video decoding method comprising: analyzing a received bitstream to determine whether the scalable bitstream is a scalable bitstream; Decoding a base layer bitstream of the bitstream; And decoding the enhancement layer bitstream of the bitstream by using the base layer information decoded by the base layer decoder when the bitstream is a scalable bitstream.

The scalable video encoding method and the scalable video decoding method may be embodied as a computer readable recording medium having recorded thereon a program for execution on a computer.

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

1 illustrates a concept of a scalable video encoding apparatus and a scalable video decoding apparatus according to an embodiment of the present invention, wherein an encoder part includes a first encoder 113 serving as a basic encoder and a second encoder serving as an improved encoder. Taking the two encoder 117 as an example, the decoder part serves as a basic decoder and serves as a first decoder 153 and an improved decoder corresponding to the first encoder 113 and corresponds to the second encoder 117. A second decoder 157 is described as an example. In one embodiment, the first encoder 113 generates a bitstream according to the basic bit and the first image format, the second encoder 117 supports the basic bit and the extension bit, and scales according to the first image format Generates a flexible bitstream. In another embodiment, the first encoder 113 generates a bitstream according to the base bit and the first video format, the second encoder 117 supports the first and second video formats, and scales according to the base bit. Generates a flexible bitstream. In another embodiment, the first encoder 113 generates a bitstream according to the basic bit and the first image format, the second encoder 117 supports the basic bit and the extension bit, and the first and second images. A scalable bitstream that supports a format is generated, or a scalable bitstream that supports a basic bit and an extended bit and supports a first and a third video format.

For convenience of explanation, the basic bit is 8 bits, the extension bit is 10 bits, the first video format is 4: 2: 0, the second video format is 4: 2: 2, and the third video format is 4: 4: 4. Let's take an example. Accordingly, as an example of the first encoder 113, a VC-1 encoder supporting 8 bit and 4: 2: 0 video format may be adopted.

Referring to FIG. 1, the bitstream 131 generated by the first encoder 113 may be decoded by the second decoder 157 as well as the first decoder 153. The scalable bitstream 137 generated by the second encoder 117 may be decoded by the second decoder 157, and the first decoder 153 may decode the enhancement layer bitstream included in the scalable bitstream. In the neglected state, decoding may be performed on the base layer bitstream. The second encoder 117 capable of providing such forward compatability corresponds to the scalable video encoding apparatus of the present invention, and the second decoder 157 corresponds to the scalable video decoding apparatus of the present invention. .

2 illustrates an example of the syntax of a scalable bitstream obtained from a scalable video encoding apparatus according to the present invention, and includes a base layer bitstream and an extension layer bitstream.

Referring to FIG. 2, the scalable bitstream may include a base layer sequence level 211, an enhancement layer sequence level 213, a base layer GOP (Group Of Pictures) level 215, The enhancement layer GOP level 217, the enhancement layer picture level 219, the base layer picture level 221, the base layer picture data 223, and the enhancement layer picture data 225 are included. Here, although the enhancement layer picture level 219 is located in front of the base layer picture level 221, the enhancement layer picture header 219 may be located behind the base layer picture header 221.

Information 211, 215, 221, 223 related to the base layer is obtained from the first encoder 113, and information 213, 217, 219, 225 related to the extended layer is obtained from the first encoder 113 and the second encoder 117. Here, the sequence consists of at least one or more coded pictures or at least one or more GOPs. The GOP is composed of at least one coded picture, and an entry-point may be used for the VC-1 codec. Here, the first picture in each GOP may provide random access. On the other hand, the picture is decomposed into macroblocks, and when the image format is 4: 2: 0, each macroblock is composed of four luminance blocks and two color difference blocks.

3A to 3D show examples of information included in each base layer or extension layer shown in FIG. 2, and FIG. 3A is information included in the extension layer sequence level 213 and may be provided in the extension layer. Profile and level information 311 and bit depth information 313 that can be supported by the enhancement layer. Here, the image format information 315 may not be included in the enhancement layer sequence level 213 when it is possible to define the base layer sequence level 211. 3B is information included in the enhancement layer picture level 219 and includes an extended index (refined QP, hereinafter referred to as R) to indicate the remaining bit depth of the enhancement layer that cannot be represented in the base layer.

3C is information included in the base layer picture level 221 and includes a basic quantization coefficient of the first encoder 113. FIG. 3D is information included in the enhancement layer picture data region 225 and shows an encoded color difference image when the image formats of the first encoder 113 and the second encoder 117 are different. Although not shown, in the present invention, when the bit depth is extended, the extended quantization level is included in the base layer picture data region 223 instead of the basic quantization level, while the extended layer picture data region 225 is extended quantization. The level is not included.

FIG. 4 illustrates an area for loading information related to an extension layer, including an extension layer identifier, in a scalable bitstream obtained from the scalable video encoding apparatus according to the present invention. When the first encoder 113 is a VC-1 encoder, in one embodiment, a start code of 4 bytes is used. In the case of the VC-1 encoder, the start code may be supported in an advanced profile or higher. On the other hand, the start code may be included in the first region in the header of each level.

A process of loading information related to an extension layer in a start code of VC-1 used as an embodiment will be described with reference to FIG. 4. In the start code, among reserved bitstream data unit (BDU) types defined in the suffix, reserved areas (451,452,453,454) reserved for future use are used to contain information related to the extension layer. Here, the BDU refers to a compressed data unit that can be parsed independently of other information in the same hierarchical level, and may be, for example, a sequence header, an entry point header, an encoded picture, or a slice. The remaining areas 411 to 421 other than the prohibited area 422 among the BDU types defined in the suffix of the start code are for containing information related to the base layer. Here, the start code is just an example, and other parts of the components of the bitstream may be used.

On the other hand, the enhancement layer includes a sequence level, a group of pictures (GOP) level, a frame level, a field level, and a slice level. The information of the extended layer may be included in any one of the second spare area 452 and the fourth spare area 454 in one embodiment. Specifically, the start code is included in the header for the sequence level of the extended layer in '0x09' in the second spare area 452 or '0x40' in the fourth spare area 454, and the second spare area 452 is included. The start code is included in the header for the GOP level of the extended layer in '0x08' or '0x3F' in the fourth spare area 454, and '0x07' or fourth spare area 454 in the second spare area 452. ), The start code is included in the header for the frame level of the extended layer in '0x3E', and the field level of the extended layer in '0x06' in the second spare area 452 or '0x3D' in the fourth spare area 454. The start code is included in the header for the start code, and the start code for the extended chrominance data is included in the header for the data of the extended layer in '0x06' in the second spare area 452 or '0x3C' in the fourth spare area 454. Included. This will be described in more detail as follows.

As information that can be included in the start code of the header for the extended layer sequence level defined at '0x09' in the second spare area 452, additional profile and level information that can be achieved by the extended layer in addition to the base layer. , And bit depth information. In detail, at the sequence level of the base layer, the profile is defined as 2 bits, '3' represents an advanced profile, and '0-2' represents a spare area. Level is defined as 3 bits, '000' is AP @ LO, '001' is AP @ L1, '010' is AP @ L2, '011' is AP @ L3, '100' is AP @ L4, ' 101-111 'represents a spare area. The bit depth information that may be achieved by the enhancement layer may be represented by a value of "N-8" (where N is the bit depth of the enhancement layer), and the bit depth information of the first encoder (113 of FIG. Depending on the bit depth, a value other than 8 can be used. Meanwhile, the information on the extended layer may include changed video format information. The video format information may be represented by using a variable included in the sequence level of the base layer, for example, a 'COLORDIFF' variable in the case of the VC-1 encoder. The second preliminary region 452 may be included in '0x09'. In other words, if the variable of the base layer is utilized, the extended layer does not need to transmit changed image format information. In the example of the 'COLORDIFF' variable, '1' is used to define the 4: 2: 0 video format, and '2' and '3' are designated as spare areas. And 4: 4: 4 video formats. Meanwhile, as information on the extended layer, an additional HRD (Hypothetical Reference Decoder) variable may be included. The HRD variable is a virtual video buffer variable that is referred to by the decoder for buffer operation.

The start code of the header for the extended layer GOP level defined at '0x08' in the second spare area 452 is designated as a spare area because it is unnecessary when the bit depth or the video format is not changed in GOP units. This is necessary when the video format is changed in units of GOP.

The start code for the picture level of the extended layer defined in '0x07' and '0x06' of the second preliminary region 452, that is, the frame level and the field level header, is generated according to progressive scan or interlaced scan. An extension index (R) for indicating the remaining bit depth of the extension layer that cannot be expressed in the base layer is included. In one embodiment, when the bit depth of the first encoder 113 is 8 bits, 'N-8' (where , N denotes the bit depth of the second encoder 117). In this case, since the expansion index (R) is used for each picture unit, the expansion index (R) is included in the picture level. According to another embodiment, when the expansion index (R) is used for each slice unit, the expansion index (for macroblock units) is used. In the case of using R), it is included in the macroblock level, and in the block level when the expansion index R is used in units of blocks. In order to calculate an expansion index R for each slice, each macroblock, or each block, a process of calculating an expansion index R of a picture level described later may be applied.

The start code for the header of the data of the extended layer defined in '0x05' of the second spare area 452 is unnecessary since it is unnecessary when the video format of the extended layer is not changed compared to the base layer. That is, when the video format of the base layer and the extension layer is the same as 4: 2: 0, data for four luminance blocks and two color difference blocks forming one macro block are transmitted in the base layer. On the other hand, if the video format of the base layer and the extended layer are different, for example, the video format of the base layer is 4: 2: 0 and the video format of the extension layer is 4: 2: 2, or the video format of the base layer is 4 : 2: 0 and the video format of the extended layer is 4: 4: 4. The video format allows the extended layer to support the changed video format while transmitting data for four luminance blocks and two chrominance blocks from the base layer. It transmits data for the difference color difference block corresponding to. On the other hand, since the data for the four luminance blocks are the same regardless of the image format, it is not necessary to transmit separate data in the extension layer.

On the other hand, the information related to the extension layer is not limited to the start code described in FIG. 4 and is stored in a reserved area reserved for future use at the sequence level, the GOP level, the picture level, the macroblock level, and the block level. May be included. In addition, in order to transmit the bitstream, the video bitstream may be a payload, and may include an extension layer identifier in various forms in a system layer for packaging the packet or various layers of a network protocol.

Next, a process of obtaining a scalable bitstream as the bit depth is expanded is as follows.

When the first encoder 113 is an 8-bit encoder and the second encoder 117 uses an N-bit encoder as an example, the start of the picture level of the enhancement layer bitstream included in the scalable bitstream obtained from the second encoder 117. The code is used to represent the rest of the bit depth that the first encoder 113 cannot express. For example, if the bit depth is N bits, and the extended quantization coefficient is QP _N , QP _N uses the basic quantization coefficient QP ₈ when the bit depth is 8 bits, and the extended index (R). It can be expressed as Equation 1. Where the extended quantization coefficient QP _N Or the basic quantization coefficient QP ₈ is derived from 'PQINDEX' for the VC-1 encoder.

According to Equation 1, the expansion index R may be obtained by Equation 2 below.

에 해당한다. 한편, QP_N 이 2^(N-8)의 배수인 경우에는 R은 0이다.Here, the expansion index (R) is in the range [-T, T-1], where T is

Corresponds to On the other hand, when QP _N is a multiple of 2 ^(N-8) , R is 0.

의 관계가 성립한다. 한편, 제2 디코더(157)에서 복원되는 DCT 계수는

이 된다. 이때, QP₁₀의 범위는

이므로, 각 확장 양자화계수 QP₁₀의 값에 따른 기본 양자화계수 QP₈의 값과 확장지수(R)의 값은 다음과 같다.Specifically, when the second encoder 117 is a 10-bit encoder, a transform coefficient, for example, a DCT (Discrete Cosine Transform) coefficient, is divided by an extended quantization coefficient QP ₁₀ and quantized, and an extended quantization level that is a quantized result is' Level ₁₀ ', where, according to equation (1)

The relationship is established. Meanwhile, the DCT coefficients restored by the second decoder 157 may be

Becomes At this time, the range of QP ₁₀ is

Therefore, the values of the basic quantization coefficient QP _{8 and} the values of the expansion index R according to the values of the respective extended quantization coefficients QP ₁₀ are as follows.

According to the target extended quantization coefficient QP ₁₀ , the second encoder 117 divides the DCT coefficient by the extended quantization coefficient QP ₁₀ and quantizes the extended quantization level 'Level ₁₀ ', which is determined as described above. The value of the basic quantization coefficient QP ₈ is included in the picture level of the base layer in the scalable bitstream and transmitted, and the value of the extension index R is included in the picture level of the extension layer in the scalable bitstream and transmitted.

을 구하고, 제2 디코더(157)는 기본계층을 통해 전송된 'Level₁₀' 값과 기본 양자화계수 QP₈, 및 확장계층을 통해 전송된 확장지수(R)을 이용하여 복원된 DCT 계수, 즉

을 구한다.Receiving such a scalable bitstream, the first decoder 153 reconstructs a DCT coefficient reconstructed by using the extended quantization level 'Level ₁₀ ' and the basic quantization coefficient QP ₈ transmitted through the base layer.

The second decoder 157 obtains a DCT coefficient reconstructed by using a 'Level ₁₀ ' value transmitted through the base layer, a basic quantization coefficient QP ₈ , and an extension index R transmitted through the extension layer.

Obtain

Specifically, in the second encoder 117, for example, if the DCT coefficient is '482' and the extended quantization coefficient QP ₁₀ is '13', the base layer has '37' having the extended quantization level "Level ₁₀ " and the basic quantization. A scalable bitstream including '3' having a coefficient QP ₈ and '1' having an extended index (R) value is formed and transmitted to the extension layer.

Meanwhile, the first decoder 153 receiving the scalable bitstream obtains '111' (= 37 X 3) as the restored DCT coefficient, and the second decoder 157 receives '481' (= as the restored DCT coefficient. 444 + 37 x 1).

Meanwhile, a process of obtaining a scalable bitstream by changing an image format will be described below.

When the image formats of the first encoder 113 and the second encoder 117 are different from each other, a scalable bitstream is formed by applying a concept of spatial scalability. For example, when the video format of the first encoder 113 is 4: 2: 0 and the video format of the second encoder 117 is 4: 2: 2, the color difference before input to the first encoder 113 is shown. The down-sampling of the block in the vertical direction is performed 1/2 times to reconstruct the 4: 2: 0 image format. The reconstructed 4: 2: 0 image is encoded by the first encoder 113 and forms a base layer bitstream. On the other hand, before being input to the second encoder 117, up-double sampling is performed in the vertical direction with respect to the reconstructed image of the 4: 2: 0 image transmitted to the base layer, and the up-sampling result is obtained. Obtain the color difference image between 4: 2: 2 reconstructed image and 4: 2: 2 original image. The obtained color difference image is encoded together with the coded block pattern (CBP) in the second encoder 117 to form an extended layer bitstream.

On the other hand, in another example, when the video format of the first encoder 113 is 4: 2: 0 and the video format of the second encoder 117 is 4: 4: 4, it is input to the first encoder 113. Prior to this, 1/2 times down sampling is performed on the color difference block in the horizontal and vertical directions to reconstruct the 4: 2: 0 image format. The reconstructed 4: 2: 0 image is encoded by the first encoder 113 and forms a base layer bitstream. On the other hand, before input to the second encoder 117, to perform the up-sampling (up sampling) twice in the horizontal and vertical direction for the reconstructed image of the 4: 2: 0 image transmitted to the base layer, The resulting color difference image between 4: 4: 4 reconstructed image and 4: 4: 4 original image is obtained. The obtained color difference image is encoded together with the coded block pattern (CBP) in the second encoder 117 to form an extended layer bitstream.

Here, the CBP used in the base layer encoder (510 of FIG. 5) of the first encoder 113 or the second encoder 117 is 6 bits in the 4: 2: 0 video format, and the 4: 2: 2 video format. In the case of 8 bits, the 4: 4: 4 video format has 12 bits. On the other hand, the CBP used in the enhancement layer encoder (530 of FIG. 5) of the second encoder 117 is performed only for the chrominance block, so that the 4: 2: 2 image format is 2 bits, which is 4: 4: 4. In case of video format, it consists of 4 bits.

FIG. 5 is a block diagram illustrating a configuration of a scalable video encoding apparatus according to a first embodiment of the present invention, and includes a base layer encoder 510, an enhancement layer encoder 530, and a bitstream combiner 550. It is made to include. The first embodiment of the scalable video encoding apparatus may be applied when the encoder and the decoder have different bit depths.

Referring to FIG. 5, the base layer encoder 510 encodes image data to generate a base layer bitstream supporting a bit depth corresponding to a base bit, and the base layer bitstream includes an extended quantization level and a base quantization coefficient. Included. Here, the extended quantization level is generated during quantization during the encoding process of the enhancement layer encoder 530.

The enhancement layer encoder 530 encodes the image data to generate an enhancement layer bitstream supporting bit depths corresponding to the extension bits, and the extension layer bitstream includes only the extension index R as shown in FIG. 3B. The quantization level is not included.

The bitstream combiner 550 combines the base layer bitstream and the enhancement layer bitstream independently of each other to generate a scalable bitstream having the syntax illustrated in FIG. 2.

6 is a block diagram showing a configuration according to a first embodiment of a scalable video decoding apparatus according to the present invention, including a bitstream analyzer 610, a base layer decoder 630, an extended layer decoder 650, and And a bit depth recovery unit 670. Here, the scalable video decoding apparatus may include a bitstream analyzer 610 and a base layer decoder 630.

Referring to FIG. 6, the bitstream analyzer 610 analyzes the received scalable bitstream to determine whether an extension layer identifier is included.

When the scalable bitstream does not include the extended layer identifier, the base layer decoder 630 decodes the base layer bitstream of the scalable bitstream to generate a basic reconstructed image having a bit depth corresponding to the base bit. Meanwhile, when the scalable bitstream includes the extended layer identifier, the base layer decoder 630 may use the extended quantization level and the basic quantization coefficient used during inverse quantization during the decoding of the base layer bitstream separated from the scalable bitstream. It is provided to the bit depth recovery unit 670.

When the scalable bitstream includes the extension layer extension, the enhancement layer decoder 650 decodes the extension layer bitstream separated from the scalable bitstream, and extracts the extension index R obtained from the picture level header of the enhancement layer. Provided to the bit depth recovery unit 670.

The bit depth reconstruction unit 670 corresponds to an extended bit using the extended quantization level and the basic quantization coefficient provided from the base layer decoder 630 and the extended index R provided from the extended layer decoder 650. The bit depth is restored, and a subsequent reconstruction process such as inverse transform is performed to generate an extended reconstructed image.

FIG. 7 is a block diagram illustrating a configuration of a scalable video encoding apparatus according to a second embodiment of the present invention. The luminance encoder 700, the downsampling unit 710, the base layer encoder 720, and the base layer are shown in FIG. A decoder 730, an upsampling unit 740, a subtractor 750, an enhancement layer encoder 760, and a bitstream combiner 770 are included. The second embodiment of the scalable video encoding apparatus may be applied when the encoder and the decoder have different image formats. Here, the luminance encoder 700, the down sampling unit 710, and the base layer encoder 720 constitute the base layer encoder 780, the luminance encoder 700, the chrominance difference image generator 790, The enhancement layer encoding unit 760 constitutes enhancement layer encoding means. Meanwhile, the color difference image generating unit 790 includes a down sampling unit 710, a base layer encoder 720, a base layer decoder 730, an upsampling unit 740, and a subtractor 750.

Referring to FIG. 7, since the luminance encoder 700 has the same luminance block regardless of the image format, the luminance encoder 700 may be shared by the base layer and the extension layer. Accordingly, the luminance encoder 700 generates a luminance block bitstream by encoding the luminance block of the input image data.

When the image format of the input image data is 4: 2: 2, the downsampling unit 710 performs 1/2 times down sampling in the vertical direction on the color difference block to perform 4: 2: 0 image format. Reconfigure In addition, when the image format of the input image data is 4: 4: 4, the downsampling unit 710 performs 1/2 times down sampling on the color difference block in the horizontal and vertical directions to perform 4: 2 down sampling. : 0 Reconstruct the video format.

The base layer encoder 720 generates a base layer luminance block bitstream by encoding the color difference block of the reconstructed 4: 2: 0 image format. The base layer decoder 730 decodes the encoded color difference block of the 4: 2: 0 image format.

When the image format of the input image data is 4: 2: 2, the upsampling unit 730 performs twice the up sampling in the vertical direction with respect to the color difference block of the decoded 4: 2: 0 image format. do. Meanwhile, when the image format of the input image data is 4: 4: 4, the upsampling unit 730 doubles upsampling in the horizontal and vertical directions with respect to the color difference block of the decoded 4: 2: 0 image format. sampling).

The subtractor 750 obtains a color difference image between the restored color difference block of the 4: 2: 2 image format and the color difference block in the original image of the 4: 2: 2 image format obtained as a result of the upsampling. In addition, the subtractor 750 obtains a color difference image between the restored color difference block of the 4: 4: 4 image format and the color difference block in the original image of the 4: 4: 4 image format. The enhancement layer encoder 760 generates an enhancement layer color difference block bitstream by encoding the color difference image.

The bitstream combiner 770 combines the base layer bitstream and the enhancement layer bitstream independently of each other to generate a scalable bitstream as shown in FIG. 2.

8 is a block diagram illustrating a configuration of a scalable video decoding apparatus according to a second embodiment of the present invention, including a bitstream analyzer 810, a luminance decoder 830, and a first base layer decoder 840. And a first enhancement layer decoder 850, an upsampling unit 860, and an adder 870. Here, the first base layer decoder 840 and the upsampling unit 860 constitute a basic color difference reconstructed image generator 880.

Referring to FIG. 8, the bitstream analyzer 810 interprets the received scalable bitstream to determine whether the extended layer identifier is included.

The luminance decoder 830 generates a reconstructed image of the base layer or the extended layer by generating a reconstructed image by decoding the luminance block bitstream among the scalable bit stream regardless of whether the scalable bitstream includes the extended layer identifier. Use it.

When the scalable bitstream does not include the extended layer identifier, the first base layer decoder 840 decodes the color difference block bitstream of the base layer among the scalable bitstreams to generate a color difference reconstruction image of the base layer. When the scalable bitstream includes the extended layer identifier, the first base layer decoder 840 decodes the color difference block bitstream of the base layer among the scalable bitstreams to generate a color difference reconstruction image of the base layer to generate the upsampling unit ( 860).

When the scalable bitstream includes the extended layer identifier, the first enhancement layer decoder 850 decodes the color difference image among the scalable bitstreams and provides the decoded color difference image to the adder 870.

The up sampling unit 860 performs up sampling on the color difference reconstructed image of the base layer provided from the first base layer decoding unit 840 and provides the up sampling unit 870 to the adder 870. At this time, upsampling is performed only in the vertical direction or upsampling is performed in the horizontal and vertical directions according to the image format used in the enhancement layer during encoding.

The adder 870 adds the color difference reconstructed image of the base layer by matching the image format by the up-sampling unit 860 and the color difference reconstructed image of the extended layer by adding the color difference difference image decoded by the first extended layer decoder 850. Create

Although not shown, a basic reconstructed image is obtained using the luminance reconstructed image generated by the luminance decoder 830 and the color difference reconstructed image of the base layer generated by the first base layer decoder 840. Similarly, an extended reconstructed image is generated by using the luminance reconstructed image generated by the luminance decoder 830 and the color difference reconstructed image of the extended layer generated by the adder 870.

9 is a block diagram showing a configuration of a scalable video encoding apparatus according to a third embodiment of the present invention, wherein the first base layer encoder 910, the first enhancement layer encoder 915, and the bit depth converter are shown. 920, the down sampling unit 925, the second base layer encoder 930, the base layer decoder 935, the upsampling unit 940, the bit depth reconstruction unit 945, the subtraction unit 950, The second enhancement layer encoder 955 and the bitstream combiner 960 are included. The third embodiment of the scalable video encoding apparatus may be applied when the encoder and the decoder have different bit depths and image formats, and combine the first embodiment of FIG. 5 and the second embodiment of FIG. Here, the first base layer encoder 910, the bit depth converter 920, the down sampling unit 925, and the second base layer encoder 930 form a base layer encoder 965. Meanwhile, the first enhancement layer encoder 915, the chrominance difference image generator 970, and the second enhancement layer encoder 955 form enhancement layer encoding means. Meanwhile, the color difference image generating unit 970 includes a bit depth converter 920, a down sampling unit 925, a second base layer encoder 930, a base layer decoder 935, and an upsampling unit 940. ), A bit depth recovery unit 945, and a subtraction unit 950.

Referring to FIG. 9, the first base layer encoder 910 generates a luminance block bitstream of a base layer that supports a bit depth corresponding to a base bit by encoding a luminance block of image data, and generates a luminance block of the base layer. The bitstream includes an extended quantization level and a basic quantization coefficient as shown in FIG. 3C. Here, the extended quantization level is generated during quantization during the encoding process of the enhancement layer encoder 530.

The first enhancement layer encoder 915 encodes the luminance block of the image data to generate a luminance block bitstream of the enhancement layer supporting a bit depth corresponding to the extension bit, and the luminance block bitstream of the enhancement layer is shown in FIG. The expansion index (R) is included.

The bit depth converter 920 converts the bit depth by dividing the color difference block of the image data by 2 ^{n2 - n1} . Here, n2 represents an extended bit and n1 represents a basic bit.

The down sampling unit 925 performs down sampling on the color difference block in which the bit depth is converted by the bit depth converter 920. At this time, downsampling is performed only in the vertical direction or downsampling is performed in the horizontal and vertical directions according to the video format to be supported.

The second base layer encoder 930 encodes the color difference block provided from the down sampling unit 925 to generate the color difference block bitstream of the base layer that supports the first image format.

The base layer decoder 935 decodes the color difference block of the encoded first image format. The up sampling unit 940 performs up sampling on the color difference block of the decoded first image format. At this time, upsampling is performed in correspondence with the down sampling unit 925. That is, upsampling is performed only in the vertical direction or upsampling is performed in the horizontal and vertical directions according to the video format to be supported.

The bit depth reconstruction unit 940 determines the bit depth of the color difference block of the decoded first image format provided from the upsampling unit 945 using the extension index R obtained by the first enhancement layer encoder 915. Restore

The subtractor 950 subtracts the color difference image between the restored color difference block of the second or third image format provided from the bit depth recovery unit 940 and the color difference block of the original image of the input second or third image format. Obtain The second enhancement layer encoder 955 encodes the color difference image to generate a color difference block bitstream of the enhancement layer.

The bitstream combiner 960 generates a base layer bitstream by combining the luminance block bitstream of the base layer and the color difference block bitstream of the base layer, and generates the luminance block bitstream of the enhancement layer and the color difference block bitstream of the extension layer. By combining, an extension layer bitstream is generated, and the base layer bitstream and the extension layer bitstream are independently combined with each other to generate a scalable bitstream as shown in FIG. 2.

FIG. 10 is a block diagram illustrating a configuration of a scalable video decoding apparatus according to a third embodiment of the present invention. The bitstream analyzer 1010, the first base layer decoder 1020, and the first enhancement layer decoder are illustrated in FIG. 1030, a first bit depth decompressor 1040, a second base layer decoder 1050, a second enhancement layer decoder 1060, an upsampling unit 1070, and a second bit depth decompressor 1080 And an adder 1090. Here, the second base layer decoder 1050, the upsampling unit 1070, and the second bit depth reconstructor 1080 constitute a basic color difference reconstructed image generator 1095.

Referring to FIG. 10, the bitstream analyzer 1010 analyzes the received scalable bitstream to determine whether an extension layer identifier is included.

When the scalable bitstream does not include the extended layer identifier, the first base layer decoder 1020 decodes the luminance block bitstream of the base layer among the scalable bitstreams to determine a base layer having a bit depth corresponding to the base bit. A luminance reconstruction image is generated. Meanwhile, when the scalable bitstream includes the extended layer identifier, the first base layer decoder 1020 may use the extended quantization level used for inverse quantization during the decoding process of the luminance block bitstream of the base layer separated from the scalable bitstream. And a basic quantization coefficient to the first bit depth reconstruction unit 1040.

When the scalable bitstream includes the extension layer extension, the first enhancement layer decoder 1030 decodes the luminance block bitstream of the extension layer among the scalable bitstreams, and decodes the extension index R obtained as a result of the first bit. It is provided to the depth recovery unit 1040.

The first bit depth reconstructor 1040 uses the extended quantization level and the basic quantization coefficient provided from the first base layer decoder 1020, and the extended index R provided from the first extended layer decoder 1030. Then, the bit depth corresponding to the extended bit is restored, and subsequent decoding processes such as inverse transform processing are performed to generate the brightness restored image of the extended layer.

When the scalable bitstream does not include the extended layer identifier, the second base layer decoder 1050 decodes the color difference block bitstream of the base layer among the scalable bitstreams to generate a color difference reconstruction image of the base layer.

When the scalable bitstream includes the extension layer identifier, the second enhancement layer decoder 1060 decodes the color difference image of the enhancement layer in the scalable bitstream and provides the decoded color difference image to the adder 1090.

The upsampling unit 1070 performs upsampling on the color difference reconstructed image of the base layer provided from the second base layer decoder 1050, and provides the upsampling unit 1070 to the second bit depth reconstruction unit 1080. At this time, upsampling is performed only in the vertical direction or upsampling is performed in the horizontal and vertical directions according to the image format used in the enhancement layer during encoding.

The second bit depth reconstructor 1080 uses the extended index R obtained by the first enhancement layer encoder 1030 to determine the color difference of the decoded second or third image format provided from the upsampling unit 1070. Restore the bit depth of the block.

The adder 1090 adds the color difference reconstruction image of the base layer in which the second bit depth reconstruction unit 1080 matches the bit depth and the image format, and adds the color difference image decoded by the second enhancement layer decoder 1060 to expand the image. A color difference reconstruction image of the layer is generated.

As in the second embodiment, the basic reconstruction is performed using the luminance reconstruction image of the base layer generated by the first base layer decoder 1020 and the color difference reconstruction image of the base layer generated by the second base layer decoder 1050. Obtain the video. The extended reconstruction image is generated by using the luminance reconstruction image of the extension layer generated by the first extension layer decoder 1030 and the color difference reconstruction image of the extension layer generated by the adder 1090.

In the above-described embodiment, at least one of a bit depth or an image format supports two codecs different from each other based on an embodiment in which a scalable bitstream has one basic bitstream and one extended bitstream. However, it is also possible to support more than one codec by having multiple extension bitstreams. In addition, in the present embodiment, although the value of the basic bit is larger than the extension bit in the bit depth as an example, various design changes are possible even when the direction of changing the bit depth, that is, the basic bit is smaller than the extension bit. In addition, various design changes are possible according to the shape of the first to third image formats. In addition, in the present exemplary embodiment, the expansion index R is allocated for each picture level. However, the expansion index R may be allocated for each slice level, for each macroblock level, or for each block level.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include any type of recording device that stores data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. And functional programs, codes and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

The best embodiments have been disclosed in the drawings and specification above. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the present invention as described above, in order to provide a new video codec with guaranteed forward compatibility, the scalable video encoder generates a scalable bitstream consisting of a base layer bitstream and an extension layer bitstream, and a scalable bitstream The existing base decoder that receives Rx performs decoding using the base layer bitstream obtained from the scalable bitstream, and the improved decoder uses both the base layer bitstream and the enhancement layer bitstream included in the scalable bitstream. By performing the decoding, there is an advantage that the improved video codec and the existing video codec are compatible with each other and coexist. Accordingly, in particular, there is an advantage that the existing window media video (WMV) codec or the VC-1 codec and a video codec supporting a new bit depth and a new video format can be used together.

As described above, the video codec according to the present invention provides forward compatibility, so that the video codec of the present invention can be used not only in an improved video codec installed in a wired or wireless electronic device such as a mobile phone, a DVD player, a portable music player, or a car stereo, but also in the existing basic video codec It can be applied to various video codecs regardless of the bit depth or image format supported.

Claims (25)

A scalable video encoding method for generating a scalable bitstream supporting a base bit and a bit depth of an extension bit different from the base bit, The scalable bitstream is A base layer bitstream including data obtained by encoding image data according to the basic bits, an extended quantization level, and a basic quantization coefficient; And And an extension layer bitstream including data obtained by encoding the image data according to the extension bits, and an extension index for compensating a difference between the extension bits and the basic bits. The scalable video encoding method of claim 1, wherein the extended quantization level is obtained during quantization during an encoding process according to a bit depth of the extended bit. A scalable video encoding method for generating a scalable bitstream supporting a first video format and a second video format different from the first video format, The scalable bitstream is A base layer bitstream comprising a luminance block bitstream obtained by encoding the luminance block of the second video format and a first color difference block bitstream obtained by encoding the chrominance block of the first video format; And And an enhancement layer bitstream including the luminance block bitstream, and a second color difference block bitstream obtained by encoding a color difference image between the restored color difference block of the second image format and the original color difference block. Flexible video coding method. The method of claim 3, wherein the color difference block of the first image format is obtained by down-sampling the color difference block of the second image format in the vertical direction, the horizontal direction and the vertical direction according to the shape of the second image format. Scalable video coding method. 4. The method of claim 3, wherein the restored color difference block of the second image format is obtained by up-sampling in the vertical direction, the horizontal direction and the vertical direction with respect to the restored color difference block of the first image format according to the shape of the second image format. A scalable video encoding method, characterized in that. 10. A scalable video encoding method for generating a scalable bitstream that supports a basic bit, a bit depth of an extension bit different from the basic bit, and a first video format and a second video format different from the first video format. , The scalable bitstream is A first luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the basic bit, an extended quantization level and a basic quantization coefficient, and a second obtained by encoding the color difference block of the first image format. A base layer bitstream comprising one color difference block bitstream; And A second luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the extension bits, and an extension index for compensating a difference between the extension bits and the basic bits; And an enhancement layer bitstream comprising a second chrominance block bitstream obtained by encoding a difference image between a reconstructed chrominance block of a format and an original chrominance block. The extended layer identifier according to any one of claims 1 to 6, wherein the enhancement layer identifier is included in at least one of a sequence level, a GOP level, a picture level, a macroblock level, and a block level of the base layer bitstream. A scalable video encoding method. 7. The scalable video encoding method according to any one of claims 1 to 6, wherein the enhancement layer identifier is included in a spare area existing in the base layer bitstream. A scalable video encoding apparatus for generating a scalable bitstream supporting a basic bit and a bit depth of an extension bit different from the basic bit, A base layer encoder for generating a base layer bitstream including data obtained by encoding image data according to bit depths of the base bits, an extended quantization level, and a base quantization coefficient; An extension layer encoder for generating an extension layer bitstream including data obtained by encoding the image data according to bit depths of the extension bits, and an extension index for compensating a difference between the extension bits and the basic bits; And And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream. 10. The scalable video encoding apparatus of claim 9, wherein the extended quantization level is obtained during quantization in the encoding process according to the bit depth of the extended bit in the enhancement layer encoder. A scalable video encoding apparatus for generating a scalable bitstream supporting a first video format and a second video format different from the first video format, A base layer encoding means for generating a base layer bit stream comprising a luminance block bitstream obtained by encoding the luminance block of the second video format and a first chrominance block bitstream obtained by encoding the chrominance block of the first video format ; Enhancement layer encoding means for generating an enhancement layer bitstream comprising the luminance block bitstream, a second chrominance block bitstream obtained by encoding a color difference image between the restored color difference block of the second image format and the original color difference block; And And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream. The method of claim 11, wherein the base layer encoding means A luminance encoder which encodes a luminance block of the second image format; A down sampling unit for converting the color difference block of the second image format into the color difference block of the first image format; And And a base layer encoder which encodes a color difference block of a first image format provided from the down sampling unit. The method of claim 11, wherein the enhancement layer encoding means A luminance encoder which encodes a luminance block of the second image format; A color difference image generator for obtaining a color difference image between the restored color difference block of the second image format and the original color difference block; And And an extension layer encoder which encodes the chrominance difference image. 10. A scalable video encoding apparatus for generating a scalable bitstream supporting a basic bit and a bit depth of an extension bit different from the basic bit, and a first video format and a second video format different from the first video format. , A first luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the basic bit, an extended quantization level and a basic quantization coefficient, and a second obtained by encoding the color difference block of the first image format. Base layer encoding means for generating a base layer bitstream consisting of one chrominance block bitstream; A second luminance block bitstream including data obtained by encoding the luminance block of the second image format according to the extension bits, and an extension index for compensating a difference between the extension bits and the basic bits; Enhancement layer encoding means for generating an enhancement layer bitstream comprising a second chrominance block bitstream obtained by encoding a difference image between the restored color difference block of the format and the original color difference block; And And a bitstream combiner configured to combine the base layer bitstream and the enhancement layer bitstream to generate a scalable bitstream. A bitstream analyzer for interpreting the received bitstream to determine whether an extension layer identifier is included; A base layer decoder for decoding a base layer bitstream of the bitstream according to a base bit to generate a basic reconstructed image when the bitstream does not include the enhancement layer identifier; An enhancement layer decoder for decoding an enhancement layer bitstream of the bitstream according to an extension bit when the bitstream includes the enhancement layer identifier; And And a bit depth reconstruction unit for reconstructing the bit depth of the enhancement layer bitstream by using the decoded base layer information when the bitstream includes the enhancement layer identifier. A bitstream analyzer for interpreting the received bitstream to determine whether an extension layer identifier is included; Base layer decoding means for decoding a luminance block bitstream and a base layer chrominance block bitstream of a first image format of the bitstream to generate a basic reconstructed image when the bitstream does not include the enhancement layer identifier; And And an enhancement layer decoding means for decoding the luminance block bitstream of the bitstream and the enhancement layer chrominance block bitstream of the second video format to generate an extension layer reconstructed image when the bitstream includes the extension layer identifier. A scalable video decoding apparatus, characterized in that. 17. The apparatus of claim 16, wherein the enhancement layer decoding means A luminance decoder which decodes a luminance block bitstream of the bitstream; An enhancement layer decoder for decoding the color difference image of the second image format included in the enhancement layer color difference block bitstream; And A chrominance reconstruction image generation unit for converting a chrominance reconstruction image of the first image format obtained by decoding the base layer chrominance block bitstream into a chrominance reconstruction image of the second image format; And And an adder configured to add the decoded color difference image and the color difference reconstructed image of the second image format. A bitstream analyzer for interpreting the received bitstream to determine whether an extension layer identifier is included; If the bitstream does not include the enhancement layer identifier, the base layer luminance block bitstream of the bitstream is decoded according to the base bits, and the base reconstruction image is decoded by decoding the base layer chrominance block bitstream of the first image format. Generating base layer decoding means; And When the bitstream includes the enhancement layer identifier, the enhancement layer luminance block bitstream of the bitstream is decoded according to the extension bits, and the bit depth of the enhancement layer bitstream is obtained by using the decoded base layer information and the extension index. And extended layer decoding means for decoding the extended layer chrominance block bitstream of the second image format to generate an extended layer reconstructed image. 19. The method of any one of claims 15 to 18, wherein the enhancement layer identifier is included in at least one of a sequence level, a GOP level, a picture level, a macroblock level, and a block level of the base layer bitstream. A scalable video decoding apparatus. 19. The scalable video decoding apparatus of any one of claims 15 to 18, wherein an enhancement layer identifier is included in a spare area existing in the base layer bitstream. Interpreting the received bitstream to determine whether an extension layer identifier is included; Generating a basic reconstruction image by decoding a base layer bitstream of the bitstream according to a base bit when the bitstream does not include the enhancement layer identifier; Decoding the enhancement layer bitstream of the bitstream according to an extension bit when the bitstream includes the enhancement layer identifier; And And reconstructing the bit depth of the enhancement layer bitstream using the decoded base layer information when the bitstream includes the enhancement layer identifier. Interpreting the received bitstream to determine whether an extension layer identifier is included; Generating a basic reconstructed image by decoding a luminance block bitstream and a base layer chrominance block bitstream of a first image format of the bitstream when the bitstream does not include the enhancement layer identifier; And And if the bitstream includes the enhancement layer identifier, decoding the luminance block bitstream and the enhancement layer chrominance block bitstream of the second image format to generate an enhancement layer reconstruction image. Scalable video decoding method. Interpreting the received bitstream to determine whether an extension layer identifier is included; If the bitstream does not include the enhancement layer identifier, the base layer luminance block bitstream of the bitstream is decoded according to the base bits, and the base reconstruction image is decoded by decoding the base layer chrominance block bitstream of the first image format. Generating; And If the bitstream includes the enhancement layer identifier, the enhancement layer luminance block bitstream of the bitstream is decoded according to the extension bits, and the bit depth of the enhancement layer bitstream is obtained by using the decoded base layer information and the extension index. Reconstructing and decoding the extended layer chrominance block bitstream of the second image format to generate an extended layer reconstructed image. 24. The method of any one of claims 21 to 23, wherein the enhancement layer identifier is included in at least one of a sequence level, a GOP level, a picture level, a macroblock level, and a block level of the base layer bitstream. Scalable video decoding method. 24. The scalable image decoding method according to any one of claims 21 to 23, wherein the enhancement layer identifier is included in a spare area existing in the base layer bitstream.

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