CN102651816B - Method and device for scanning transformation coefficient block - Google Patents

Abstract

The embodiment of the present invention discloses a scanning method and device for a transform coefficient block, wherein the implementation of the method includes: detecting the texture of the coded block as a reference of the block to be coded; selecting the texture from the preset candidate scanning order Corresponding scanning order; perform rate-distortion optimization processing on the Z-shaped scanning order and the selected scanning order to obtain the optimal scanning order; if the preferred scanning order is the Z-shaped scanning order, then perform the transformation coefficient block of the block to be encoded according to the optimal scanning order Scanning; if the preferred scanning order is other than the zigzag scanning order, then reset the transformation coefficient block of the block to be encoded to the transformation coefficient block scanned in the scanning order of the predetermined rule; according to the predetermined rule The scanning order scans the reset transform coefficient block of the block to be encoded; and encodes the indication information whether the scanning order used for scanning is a zigzag scanning order into the code stream. The above solutions can save resources and have higher efficiency.

Description

Scanning method and device for transform coefficient block

technical field

The invention relates to the field of communication technology, in particular to a method and device for scanning transform coefficient blocks in video codec.

Background technique

Scanning of transform coefficient blocks is an integral part of video codec technology. The scanning of the transform coefficient block has the following applications: at the video encoding end, the video encoding end scans the transformed two-dimensional transform coefficient block in the transform domain, so that the two-dimensional transform coefficient in the transform coefficient block is transformed into a one-dimensional Sequence of transform coefficients. In this process, it is necessary to select the scanning order according to the transformation method of the current transformation coefficient block, so that the scanned one-dimensional transformation coefficient sequence tends to be arranged from large to small, thereby improving the coding efficiency; According to the transform mode, the decoder selects the inverse scanning order to convert the one-dimensional transform coefficient sequence into a two-dimensional transform coefficient block.

At present, at the video encoding end, during the video encoding process, the prediction residual is transformed first to obtain transform coefficients. Before transform coefficient scanning, reference block information and quantized transform coefficient information can also be obtained; when high-frequency When the transform coefficient is non-zero, from the following three scan modes: Z-shape scan mode, horizontal scan mode and vertical scan mode, select a set of optimal scan modes through the rate-distortion optimization criterion; then use the selected scan mode to transform The coefficients are scanned, and the selection information of the scanning mode is encoded into the code stream and passed to the decoder.

At the encoding end of the video, it is necessary to select the mode among the three scanning modes, which makes the encoding end more complex; in addition, the selection information of the scanning mode needs to be encoded into the code stream, which affects the compression encoding efficiency.

Contents of the invention

Embodiments of the present invention provide a scanning method and device for transform coefficient blocks, which improve compression coding efficiency.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Detecting the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction;

Selecting a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include scan orders other than the zigzag scan order;

Performing rate-distortion optimization processing on the Z-shaped scanning order and the selected scanning order to obtain the preferred scanning order;

If the preferred scanning order is a zigzag scanning order, then scan the transform coefficient blocks of the block to be encoded according to the preferred scanning order;

If the preferred scanning order is a scanning order other than the zigzag scanning order, reset the transform coefficient block of the block to be coded to be the transform coefficient block scanned according to the scanning order of the predetermined rule; Scanning the reset transform coefficient block of the block to be encoded;

Indicating whether the scanning sequence used for scanning is a zigzag scanning sequence is encoded into the code stream.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Analyzing the code stream to obtain indication information, if the received indication information of the code stream indicates that the scanning order is not a zigzag scanning order, then detecting the texture of the decoded block as a reference of the block to be decoded, the texture embodies the The change rule of the transform coefficient block in each direction of the transform coefficient block of the decoding block; select the scan order corresponding to the texture from the preset candidate scan order; the preset candidate scan order includes other than the zigzag scan order scan order;

Scanning the transform coefficient blocks of the block to be decoded according to the scanning order of predetermined rules;

If the selected scanning order is different from the scanning order of the predetermined rule, after the scanning is completed, the transform coefficient blocks of the block to be decoded are reset to follow the selected scanning order according to the selected scanning order and the scanning order of the predetermined rule Scanned block of transform coefficients.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Detecting the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction;

Select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include Z-shaped scan orders and scan orders other than Z-shaped scan orders;

If the selected scanning order is a zigzag scanning order, scan the transform coefficient block of the block to be encoded according to the zigzag scanning order; if the selected scanning order is other scanning order than the zigzag scanning order, then scan The transform coefficient block of the block is reset to a transform coefficient block conforming to the zigzag scanning order; and the reset transform coefficient block of the block to be encoded is scanned according to the zigzag scanning order.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Detecting the texture of the decoded block as a reference of the block to be decoded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

Select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include Z-shaped scan orders and scan orders other than Z-shaped scan orders;

If the selected scanning order is a zigzag scanning order, scan the transform coefficient block of the block to be decoded according to the zigzag scanning order;

If the selected scanning order is a scanning method other than the zigzag scanning order, resetting the transform coefficient block of the block to be decoded from the transform coefficient block conforming to the zigzag scanning order to the transform coefficient block conforming to the selected scanning order; Scanning the reset transform coefficient block of the block to be decoded according to the selected scanning manner.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The first detection unit is configured to detect the texture of the coded block as a reference of the block to be coded, the texture embodies the change law of the transformation coefficient of the transformation coefficient block in each direction of the block to be coded;

A first selection unit, configured to select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include scan orders other than the zigzag scan order;

The first processing unit is configured to perform rate-distortion optimization processing on the preset zigzag scanning order and the selected scanning order to obtain the preferred scanning order;

A first resetting unit, configured to reset the transformation coefficient block of the block to be coded to the transformation coefficient block scanned according to a predetermined scanning order if the preferred scanning order is other than the zigzag scanning order;

The first scanning unit is configured to scan the transformation coefficient blocks of the block to be coded according to the preferred scanning order if the preferred scanning order is a zigzag scanning order; if the preferred scanning order is a scanning order other than the zigzag scanning order, then Scanning the reset transform coefficient blocks of the block to be encoded according to the scanning order of the predetermined rule;

The first encoding unit is configured to encode indication information indicating whether the scanning order used for scanning is a zigzag scanning order into the code stream.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The second parsing unit is used to parse the code stream to obtain indication information;

The second detection unit is configured to detect the texture of the encoded or decoded block as a reference of the block to be decoded if the received indication information of the code stream indicates that the scanning order is not a zigzag scanning order, and the texture reflects the to-be-decoded block. The change law of the transform coefficients of the transform coefficient block in each direction in the decoding block;

The second selection unit is configured to select a scanning order corresponding to the texture from preset candidate scanning orders; the preset candidate scanning orders include scanning orders other than the zigzag scanning order;

The second scanning unit is configured to scan the transform coefficient blocks of the block to be decoded according to a scanning order of predetermined rules;

The second resetting unit is used to reset the transform coefficient block of the block to be decoded according to the selected scanning order and the scanning order of the predetermined rule after the scanning is completed if the selected scanning order is different from the scanning order of the predetermined rule. Set to a block of transform coefficients that can be scanned in the selected scan order.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The third detection unit is configured to detect the texture of the coded block as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction;

A third selection unit, configured to select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include Z-shaped scan orders and other scan orders other than Z-shaped scan orders;

The third resetting unit is used to reset the transform coefficient block of the block to be encoded to a transform coefficient block conforming to the Z-shape scan order if the selected scan order is other than the Z-shape scan order;

The third scanning unit is configured to scan the transformation coefficient blocks of the block to be encoded according to the zigzag scanning order if the selected scanning order is the zigzag scanning order; The transform coefficient block of the block to be coded is scanned.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The fourth detection unit is configured to detect the texture of the decoded block as a reference of the block to be decoded, and the texture reflects the change law of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

A fourth selection unit, configured to select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include Z-shaped scan orders and other scan orders other than Z-shaped scan orders;

The fourth resetting unit is used to reset the transformation coefficient block of the block to be decoded from the transformation coefficient block conforming to the Z-shape scanning order to conforming to the selection if the selected scanning order is other than the Z-shape scanning order. Transform coefficient blocks in scan order;

The fourth scanning unit is configured to scan the transform coefficient block of the block to be decoded according to the zigzag scanning order if the selected scanning order is the zigzag scanning order; The transform coefficient block of the block to be encoded is scanned.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Detecting the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction;

If the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, reset the residual data block of the block to be encoded, so that the transformation coefficient block corresponding to the residual data block is a transformation coefficient block scanned according to the predetermined rule ;

Scanning the transform coefficient blocks of the block to be encoded according to a preferred scanning order, the preferred scanning order is a scanning order obtained by performing rate-distortion optimization on the zigzag scanning order and the scanning order of predetermined rules;

Indicating whether the scanning sequence used for scanning is a zigzag scanning sequence is encoded into the code stream.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Analyze the code stream to obtain the instruction information, and the instruction information of the code stream indicates the scanning order;

Scanning the transform coefficient blocks of the block to be decoded according to the scanned scanning order;

If the indication information of the code stream indicates that the scanning order is not Z-shaped scanning, then detect the texture of the decoded block as a reference of the block to be decoded, and the texture reflects that the transformation coefficient block of the block to be decoded is transformed in each direction The changing law of coefficients; if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, the residual of the block to be decoded will be converted according to the scanning order corresponding to the texture and the scanning order of the predetermined rule. The difference data block is reset, so that the transform coefficient block corresponding to the residual data block is a transform coefficient block that can be scanned according to a scanning order of a predetermined rule.

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Detecting the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction;

If the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, reset the residual data block of the block to be encoded, so that the transformation coefficient block corresponding to the residual data block is a transformation coefficient block scanned according to the predetermined rule ;

Scanning the transform coefficient blocks of the block to be coded according to a scanning order of predetermined rules;

An embodiment of the present invention provides a method for scanning a transform coefficient block, including:

Scanning the transform coefficient blocks of the block to be decoded according to the scanning order of predetermined rules;

Detecting the texture of the decoded block as a reference of the block to be decoded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

If the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, the residual data block of the block to be decoded is reset according to the scanning order corresponding to the texture and the scanning order of the predetermined rule , making the transform coefficient block corresponding to the residual data block a transform coefficient block that can be scanned according to a scanning order of a predetermined rule.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The fifth detection unit is configured to detect the texture of the coded block as a reference of the block to be coded, the texture embodies the change law of the transformation coefficient of the transformation coefficient block of the block to be coded in each direction;

The fifth resetting unit is configured to reset the residual data block of the block to be encoded if the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, so that the transformation coefficient block corresponding to the residual data block is Transform coefficient blocks scanned according to predetermined rules;

The fifth processing unit is configured to perform rate-distortion optimization processing on the preset zigzag scanning order and the scanning order of predetermined rules to obtain the preferred scanning order;

The fifth scanning unit is configured to scan the transform coefficient block of the block to be encoded according to the preferred scanning order;

The fifth encoding unit is configured to encode indication information indicating whether the scanning order used for scanning is a zigzag scanning order into the code stream.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

A sixth parsing unit, configured to parse the code stream to obtain indication information;

The sixth scanning unit is configured to scan the transform coefficient blocks of the block to be decoded according to the analyzed scanning order;

The sixth detection unit is configured to detect the texture of the decoded block as a reference of the block to be decoded if the indication information of the code stream indicates that the scanning order is not Z-scan, and the texture reflects the transformation of the block to be decoded The change law of the coefficient block transform coefficient in each direction;

The sixth resetting unit is used to, if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, according to the scanning order corresponding to the texture and the scanning order of the predetermined rule, the The residual data block of the block is reset, so that the transform coefficient block corresponding to the residual data block is a transform coefficient block that can be scanned according to a scanning order of a predetermined rule.

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

The seventh detection unit is used to detect the texture of the coded block as a reference of the block to be coded, and the texture embodies the change law of the transformation coefficient of the transformation coefficient block of the block to be coded in each direction;

The seventh resetting unit is configured to reset the residual data block of the block to be encoded if the scanning order corresponding to the texture is not consistent with the scanning order of the predetermined rule, so that the transformation coefficient block corresponding to the residual data block is Transform coefficient blocks scanned according to predetermined rules;

The seventh scanning unit is configured to scan the transform coefficient block of the block to be coded according to a scanning order of predetermined rules;

An embodiment of the present invention provides a scanning device for transform coefficient blocks, including:

An eighth scanning unit, configured to scan the transform coefficient blocks of the block to be decoded according to a scanning order of predetermined rules;

The eighth detection unit is configured to detect the texture of the decoded block as a reference of the block to be decoded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

The eighth reset unit is used for if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, the corresponding scanning order of the texture and the scanning order of the predetermined rule will be decoded The residual data block of the block is reset, so that the transform coefficient block corresponding to the residual data block is a transform coefficient block that can be scanned according to a scanning order of a predetermined rule.

The above-mentioned technical solution only needs to choose between the predetermined scanning order and the Z-shaped scanning order, which is a choice of one of two choices. Compared with the choice of one of three choices, one less bit can be used to carry the selected information. When encoding header information, it will save resources; in addition, it will be more efficient when selecting.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 2A is a schematic diagram of the scanning sequence of the vertical texture according to the embodiment of the present invention;

FIG. 2B is a schematic diagram of the scanning sequence of the horizontal texture according to the embodiment of the present invention;

FIG. 2C is a schematic diagram of the scanning sequence of oblique textures according to an embodiment of the present invention;

Fig. 3 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 4 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 5 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a device according to an embodiment of the present invention;

Fig. 7 is a schematic diagram of the device structure of the embodiment of the present invention;

Fig. 8 is a schematic structural diagram of the device of the embodiment of the present invention;

Fig. 9 is a schematic diagram of the structure of the device according to the embodiment of the present invention.

Fig. 10 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 11 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 12 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 13 is a schematic flow chart of the method of the embodiment of the present invention;

Fig. 14 is a schematic structural diagram of the device of the embodiment of the present invention;

Fig. 15 is a schematic structural diagram of the device of the embodiment of the present invention;

Fig. 16 is a schematic structural diagram of the device of the embodiment of the present invention;

Fig. 17 is a schematic diagram of the structure of the device according to the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

During the inter-frame encoding process, the encoding end of the embodiment of the present invention, for each block to be encoded, selects the optimal inter-frame encoding type from various inter-frame encoding types according to the rate-distortion criterion, and obtains motion information at the same time. and the encoded reconstructed frame information to obtain the predicted value of the block to be encoded, and make a difference between the predicted value and the pixel value of the block to be encoded to obtain the residual value, and perform transformation, quantization, scanning, and entropy encoding operations on the residual value in sequence , into the code stream, and at the same time encode the motion information into the code stream to complete the encoding process. The scanning in the process of encoding and decoding is described in detail below. The transformation mentioned in the embodiment of the present invention may be a discrete cosine transform (Discrete Cosine Transform, DCT); it may also be a multi-transform technique, such as KL transform (Karhunen Loeve Transform, KLT), which is not limited in this embodiment of the present invention.

A method for scanning a transform coefficient block, the solution of this embodiment can be executed at the encoding end, as shown in Figure 1, including:

101: Detect the texture of the coded block used as a reference of the block to be coded, the above texture reflects the change rule of the transformation coefficient block in each direction of the transformation coefficient block of the above-mentioned block to be coded;

The above 101 belongs to a physical derivation. The coded texture used as a reference is similar to the texture of the current block to be coded, and the texture to be coded is similar to the residual texture to be coded. The distribution law of the transformation coefficient is closely related to the residual texture relevant. More specifically, the above-mentioned textures include horizontal textures, vertical textures and oblique textures; the oblique textures can also be regarded as no textures.

More specifically, the above-mentioned detection of the texture of the decoded block includes:

When performing inter-frame decoding, calculate the horizontal gradient value in the horizontal direction and the vertical gradient value in the vertical direction of the transform coefficient block; the horizontal gradient value is the sum of the absolute values of the differences between adjacent pixels in the horizontal direction , the vertical gradient value is the sum of the absolute values of the differences between adjacent pixel points in the vertical direction; the above-mentioned transform coefficient block as a reference is the change coefficient block of the above-mentioned decoded block;

If the horizontal gradient value is greater than N times the vertical gradient value, the texture is determined to be a vertical texture, and the vertical gradient value is greater than N times the horizontal gradient value, then the texture is determined to be a horizontal texture, otherwise it is determined that the texture is an oblique texture; the above N is the first The preset value, N can be determined by the resolution width, for example, N=2 when the resolution width is greater than 1000, and N=1.5 when the resolution width is less than 1000; The embodiment of the invention does not limit this.

When performing intra-frame decoding, if the vertical offset of the intra-frame prediction mode direction is within M, the texture is determined to be a vertical texture, and the horizontal offset of the intra-frame prediction mode direction is within M, then the texture is determined It is a horizontal texture, otherwise it is determined that the texture is an oblique texture; the above M is the second preset value, and M can also be determined by the resolution width, for example, it can be set to 5, or it can be set to other values such as 3, 4, etc., for this purpose The embodiments of the invention are not limited.

Further, the embodiment of the present invention also provides an implementation method of modifying the preset value: if the ratio of the horizontal texture to the vertical texture exceeds the third preset value in the decoded block, then reduce the value of N; if the ratio of the horizontal texture to the vertical texture If the ratio of straight texture is less than N, increase the value of N. The third preset value can be obtained in the following manner. By performing intra-frame coding on the sequence of transform coefficients with different characteristics, and statistically calculating the proportional relationship between the horizontal and vertical prediction directions, the proportional relationship can be used as the third preset value.

Optionally, if there is an encoded block or a decoded block, then the texture of the encoded block or decoded block is known, and this information can be used to reduce the amount of computation; the above detection of the texture of the transform coefficient block includes: detecting the texture to be decoded The block sets the texture of the coded block or decoded block within the temporal or spatial distance, and determines the detected texture as the texture of the transform coefficient block.

102: Select a scanning order corresponding to the above-mentioned texture from the preset candidate scanning orders; in this embodiment, the preset candidate scanning orders include scanning orders other than the zigzag scanning order;

The scanning order corresponding to the above textures includes as shown in Figure 2A to Figure 2C: vertical texture corresponds to the horizontal scanning order of progressive scanning, horizontal texture corresponds to the vertical scanning order of column-by-column scanning, and oblique texture corresponds to the Z-shaped sequential scanning. shape scan order. 2A to 2C take a 4X4 matrix as an example, where the circle represents the transformation coefficient, the value under the circle represents the coordinate (ie position) of the transformation coefficient, and the direction of the arrow represents the scanning direction, that is, the scanning order. It should be noted that the matrix on the left side of Figure 2C and the matrix on the right represent a Z-shaped scanning order, and the Z-shaped scanning order can be customized, so there are many possible types, and the examples in Figure 2C are not exhaustive; therefore, this paper The embodiment of the invention does not limit the zigzag scanning sequence.

103: Perform rate-distortion optimization processing on the preset zigzag scanning order and the selected scanning order to obtain the optimal scanning order;

104: If the preferred scanning order is a zigzag scanning order, scan the transform coefficient blocks of the block to be encoded according to the preferred scanning order; if the above preferred scanning order is other than the zigzag scanning order, then transform The coefficient block is reset to the transform coefficient block scanned according to the scanning order of the predetermined rule; the reset transform coefficient block of the block to be encoded is scanned according to the scanning order of the predetermined rule;

More specifically, in the above 104, if the above-mentioned preferred scanning order is other than the zigzag scanning order, the transform coefficient block of the block to be coded is reset to the transform coefficient block scanned according to the scanning order of the predetermined rule; according to the above Scanning the reset transform coefficient blocks of the blocks to be coded in a scanning order of predetermined rules includes:

If the preferred scanning order is the first scanning order, the transform coefficients of the block to be encoded are transposed, and the transposed transform coefficient blocks of the block to be encoded are scanned according to the second scanning order; the first scanning order and the second scanning order The scan order of the second scan order is symmetric;

If the preferred scanning order is the second scanning order, the transform coefficient blocks of the block to be encoded are scanned according to the second scanning order.

It should be noted that the above "first" and "second" are used to distinguish two scanning sequences with a symmetrical relationship, and there is no other limitation. For example, there are two symmetrical scanning sequences between the horizontal scanning sequence and the vertical scanning sequence. The scanning order, if the first scanning order is a horizontal scanning order, then the second scanning order is a vertical scanning order, and if the first scanning order is a vertical scanning order, then the second scanning order is a horizontal scanning order.

More specifically, in the above 104, the transform coefficient block of the block to be coded is reset to a transform coefficient block scanned according to the scanning order of the predetermined rule; the transformed coefficient block of the block to be coded after the reset is The block scanning includes: resetting the transform coefficient blocks of the block to be coded to conform to the zigzag scanning order; and scanning the reset transform coefficient blocks of the block to be coded according to the zigzag scanning order. If this method is adopted, the instruction information in step 105 may not be transmitted, which will be described in detail in subsequent embodiments.

105: Encode the indication information of whether the scanning sequence used for scanning is a zigzag scanning sequence into the code stream.

In the above implementation mode, it is only necessary to choose between the predetermined scanning order and the Z-shaped scanning order, which is a choice of one of two choices. Compared with the choice of one of three choices, one less bit can be used to carry the selected information. Therefore, in the future When encoding header information, it will save resources; in addition, it will be more efficient when selecting. In addition, by transposing the transform coefficient matrix, multiplexing the same entropy coding model can improve the coding efficiency.

More specifically, this embodiment also provides an example of an implementation manner of presetting the candidate scanning order. The above preset candidate scanning order includes:

Pre-defined scanning rules, which determine the order of scanning; or, pre-count the number of non-zero transform coefficients at each position of two or more transform coefficient blocks, and arrange each non-zero For the positions of the transform coefficients corresponding to the number of times, the order of the positions of the transform coefficients obtained by arranging is determined as a preset candidate scanning order.

The embodiment of the present invention gives an example in the latter implementation of the above example of the preset candidate scanning mode: In the encoder, according to the texture of the residual block, the quantization residual can be divided into three categories: horizontal texture The corresponding quantized residual, the quantized residual corresponding to the vertical texture, and the quantized residual corresponding to the oblique texture; the way to determine the scanning order is to establish a counter group with the same number of transform coefficients (for example, 4x4 transform is 16 counters) , and then use the counter to count, specifically: judge whether each transform coefficient is zero, if it is not zero, then add one to the counter at the corresponding position; after the number of detected transform coefficient blocks reaches the set number, each counter has its own The value of the count; at this time, the values of each counter can be arranged in descending order, and the order of the positions of the above-mentioned transformation coefficients obtained by the arrangement can be determined as the preset candidate scanning order. Using this method, when scanning is performed according to the obtained order, the position of the transformation coefficient corresponding to the counter with a large value will be arranged at the front in the scanning order.

Example scheme 1. The following is a specific description of the scanning link in the encoding process:

A: Encode according to the encoding process until the transformation coefficient encoding is performed;

B: If inter-frame coding (Inter) is performed, the texture of the reference block is detected to obtain its texture (horizontal Hor texture, vertical ver texture, oblique texture); if intra-frame coding (Intra) is performed In some cases, if the direction of the intra prediction mode (ipmode) is ver+/-5, the texture is a vertical texture, the direction is Hor+/-5, and the texture is a horizontal texture, and in other cases it is an oblique texture. The offset set in this embodiment is 5, of course, it can also be set to other values, which is not limited in this embodiment of the present invention. A scanning order corresponding to the above texture is selected from preset candidate scanning orders according to the obtained texture.

The detection method in the above B can be:

B1: Determine the detection step size. This step sets different detection steps for different transformation units (Transform Unit, TU). For example, when TU=4, the step size is 1, when TU=8, the step size is 1, and when TU=16, the step size is 2. When TU=32, the step size is 4, or the corresponding step size of all sizes of TUs is 1; if all sizes of TUs use the same step size, then the step B1 can be omitted.

B2: In the reference block (that is, the transform coefficient block used as a reference), the difference value is calculated for every two pixels of adjacent detection steps in the horizontal direction; the absolute value of the accumulated difference value is obtained to obtain the horizontal gradient value;

B3: Calculate the difference between every two pixels of the adjacent detection step in the vertical direction in the reference block; accumulate the absolute value of the difference to obtain the vertical gradient value;

B4: If the horizontal gradient value is greater than N times the vertical gradient value, then determine its texture as vertical texture; if the vertical gradient value is greater than N times the horizontal gradient value, determine its texture as horizontal texture; otherwise it is oblique texture ; After B4, it is also possible to further judge whether the threshold N needs to be updated according to the proportion distribution of horizontal, vertical and oblique textures in the coded block. The judgment method is to judge whether the ratio of the horizontal gradient value to the vertical gradient value exceeds the preset value , if yes, increase the preset value, otherwise, decrease the preset value. (wherein the preset value is obtained by the following method, by performing intra-frame coding on the sequence of transform coefficients with different characteristics, and statistically calculating the proportional relationship between the horizontal and vertical prediction directions, the proportional relationship can be used as the preset value. Step C is to preset An automatic correction process of setting values, which is not a mandatory step.

In addition, for the method of step B detection in the above encoding process, there may be an alternative solution: detect the texture of the encoded block or decoded block within the set time domain or spatial domain distance of the block to be decoded, and determine the detected texture as the The texture of the transform coefficient block for the decoded block. More specifically, for example, the texture of the decoded block surrounding (upper, left, upper left, upper right, lower left) of the block to be decoded is detected as the texture of the transform coefficient block of the current block to be decoded.

C: performing rate-distortion optimization processing on the preset Z-shaped scanning order and the selected scanning order to obtain the optimal scanning order;

D: Determine whether the preferred scanning sequence is a Z-shaped scanning sequence, if yes, execute G, if not, execute E;

E: If the scanning order is vertical, transpose the transform coefficients; if the scanning order is horizontal, continue;

F: Scan the transformation coefficient block to be scanned according to the horizontal scanning order and the relevant entropy coding model, and then continue the subsequent coding process.

G: Encode and scan the transformation coefficient blocks to be scanned according to the zigzag scanning sequence and the relevant entropy coding model, and then continue the subsequent coding process.

H: Encode the indication information of whether the scanning sequence used for scanning is a zigzag scanning sequence into the code stream. This step can be performed during the execution of step G or F. It can be understood that, after the encoding is completed, the encoding result (code stream) will be sent to the decoding end, which will not be described in other places in this embodiment of the present invention.

Correspondingly, the embodiment of the present invention also provides a scanning method for transform coefficient blocks performed at the decoding end, as shown in FIG. 3 , including:

301: Analyze the code stream to obtain instruction information;

302: If the received code stream indication information indicates that the scanning order is a zigzag scanning order, scan the transformation coefficient blocks of the block to be decoded according to the zigzag scanning order; the scanning process ends.

303: If the received indication information of the code stream indicates that the scanning order is not a zigzag scanning order, then detect the texture of the decoded block as a reference of the block to be decoded, the texture reflects the transform coefficient block of the block to be decoded in each The change law of the transformation coefficient in the direction; select the scanning sequence corresponding to the above-mentioned texture from the preset candidate scanning sequence; in this embodiment, the above-mentioned preset candidate scanning sequence includes other scanning sequences other than the Z-shaped scanning sequence;

304: Scan the transform coefficient blocks of the block to be decoded according to the scanning order of the predetermined rule; if the selected scanning order is the same as the scanning order of the predetermined rule, the scanning process ends.

305: If the selected scanning order is different from the scanning order of the above-mentioned predetermined rules, after the scanning is completed, reset the transform coefficient blocks of the block to be decoded to follow the selected scanning order according to the above-mentioned selected scanning order and the scanning order of the predetermined rules Scanned block of transform coefficients. It can be understood that this embodiment corresponds to the encoding end, so the transform coefficient block of the block to be decoded has been reset by the encoding end according to the above predetermined rule.

More specifically, the transform coefficient blocks of the block to be decoded are scanned according to the scanning order of the predetermined rule; if the selected scanning order is different from the scanning order of the predetermined rule, after the scanning is completed, The scan order resets the transform coefficient blocks of the block to be decoded to transform coefficient blocks that can be scanned in the selected scan order including:

If the selected scanning order is the first scanning order, scan the transform coefficient block of the block to be decoded according to the second scanning order; after the scanning is completed, transpose the transform coefficient block of the block to be decoded; the first scanning order and the second scanning order The scanning sequence is symmetrical, and the second scanning sequence is the scanning sequence of the above-mentioned predetermined rules.

Example 2: The decoding process is similar to the scanning method of the encoding process:

A: Decode according to the decoding process until the transformation coefficient analysis is performed;

B: Analyze the code stream to obtain the instruction information, which is the instruction information in the step H of the encoding process; judge whether the instruction information indicates that the scanning sequence is a Z-shaped scanning sequence; if so, execute E; otherwise, execute C;

C: For this step, you can refer to step B of Example Scheme 1, select the scanning order corresponding to the above texture from the preset candidate scanning order according to the obtained texture, and then execute D;

D: If the texture direction corresponds to the vertical scanning order, analyze and scan the transformation coefficient block to be scanned according to the horizontal scanning order and the relevant entropy coding model, and then transpose the transformation coefficients to continue the subsequent decoding process; if the texture direction corresponds to the horizontal Scanning order, analyze and scan the transformation coefficient blocks to be scanned according to the horizontal scanning order and related entropy coding model, and continue the subsequent decoding process;

E: Analyze and scan the transformation coefficient blocks to be scanned according to the zigzag scanning sequence and the relevant entropy coding model, and then continue the subsequent decoding process.

The above examples of schemes 1 and 2 only need to choose between the horizontal and vertical scanning order and the Z-shaped scanning order, which is a choice between the two, compared to the horizontal, vertical and Z-shaped scanning order (zig-zag ) can use one less bit to carry the selected information, so when it is encoded into the encoding header information, it will save resources; in addition, it is more efficient when selecting.

The embodiment of the present invention also provides another scanning method for the transform coefficient block, which is implemented in the coding device, and further improves the coding efficiency without transmitting instruction information on the basis of the above two solutions; As shown in Figure 4, including:

401: Detect the texture of the coded block used as a reference of the block to be coded, the above texture reflects the change rule of the transformation coefficient block in each direction of the transformation coefficient block of the above-mentioned block to be coded;

402: Select a scan sequence corresponding to the above texture from the preset candidate scan sequences; the preset candidate scan sequences in this embodiment include Z-shaped scan sequences and other scan sequences other than the Z-shaped scan sequence;

403: If the selected scanning order is a zigzag scanning order, scan the transform coefficient block of the block to be encoded according to the zigzag scanning order; if the selected scanning order is other than the zigzag scanning order, then The transform coefficient blocks of the encoding block are reset to transform coefficient blocks conforming to the zigzag scanning order; the reset transform coefficient blocks of the block to be encoded are scanned according to the zigzag scanning order.

Correspondingly, the embodiment of the present invention also provides another scanning method for the transform coefficient block. This solution is implemented in the decoding device, and the coding efficiency can be further improved without transmitting instruction information; as shown in FIG. 5 , it includes:

Example scheme 1. The following is a specific description of the scanning link in the encoding process:

The following is a specific description of the scanning link in the encoding process:

A: Encode according to the encoding process until the transformation coefficient encoding is performed;

B: For this step, refer to Step B of Example Scheme 1, and select the scan order corresponding to the above texture from the preset candidate scan orders according to the obtained texture;

C: According to the selected scan order, reset the position of the transformation coefficients to conform to the positional relationship of the zigzag scan order;

D: Encoding and scanning the transformation coefficient blocks to be scanned according to the zigzag scanning sequence and the related entropy coding model, and then continue the subsequent coding process.

501: Detect the texture of the decoded block used as a reference of the block to be decoded, the texture reflects the change rule of the transform coefficient block in each direction of the transform coefficient block of the block to be decoded;

502: Select a scan sequence corresponding to the above texture from the preset candidate scan sequences; the preset candidate scan sequences in this embodiment include Z-shaped scan sequences and other scan sequences other than the Z-shaped scan sequence;

503: If the selected scanning order is a zigzag scanning order, scan the transformation coefficient blocks of the block to be decoded according to the zigzag scanning order;

504: If the selected scanning order is a scanning method other than the zigzag scanning order, reset the transform coefficient block of the block to be decoded from the transform coefficient block conforming to the zigzag scanning order to the transform coefficient block conforming to the above selected scanning order ; Scan the reset transform coefficient block of the block to be decoded according to the selected scanning mode.

The corresponding decoding process is similar to the scanning method of the encoding process:

A: Decode according to the decoding process until the transformation coefficient analysis is performed;

B: Analyzing and scanning the transformation coefficient blocks to be scanned according to the Z-shape scanning sequence and the relevant entropy coding model;

C: For this step, refer to Step B of Example Scheme 1, and select the scanning sequence corresponding to the above texture from the preset candidate scanning sequences according to the obtained texture;

D: If the texture direction corresponds to the vertical scanning order, reset the position of the transformation coefficient to conform to the positional relationship of the vertical scanning order; if the texture direction corresponds to the horizontal scanning order, reset the position of the transformation coefficient to conform to the position of the horizontal scanning order relationship; if the texture direction corresponds to the Z-shaped scanning order, this step is not performed;

E: continue the subsequent decoding process;

For the single-scan scheme, the scanning order of the transform coefficients (ie, the first scan, the second scan, the third scan...) corresponds to a unique frequency domain position relationship (ie (0, 0), (0, 1), (1, 0)...), so when analyzing the scanned point, it can be given a possible value according to the value of the analyzed point around its frequency domain (that is, to establish an entropy coding model, you can see The operation is a kind of prediction, which makes the encoding more efficient). For the multi-scan solution, since the scan order has been determined before analyzing the transform coefficients, that is, the relationship between the scan order and the frequency domain position has been determined, each scan order can still be performed in the manner of the single-scan solution. In the embodiment of the present invention, before analyzing the transformation coefficient, it can determine whether it is zig-zag and cannot distinguish between horizontal and vertical. Therefore, if no operation is performed, the relationship between the scanning order and the frequency domain position cannot be determined when it is not zig-zag. There is no way to establish an entropy coding model, and it cannot be decoded. The above solution solves this problem by resetting.

The following is the result of a simulation experiment performed on the solution provided by the embodiment of the present invention.

Test conditions: JCTVC high efficiency low delay test condition;

Test results: the third column is the result of the technical solution integrated in TMuC (new generation video coding test software platform), and the fourth column is the result of the embodiment of the present invention. It can be seen that the efficiency of the embodiment of the present invention is higher.

A scanning device for a transform coefficient block, as described above in Figure 6, comprising:

The first detection unit 601 is configured to detect the texture of the coded block as a reference of the block to be coded, and the above texture reflects the change law of the transformation coefficient of the transformation coefficient block of the above-mentioned block to be coded in each direction;

The first selection unit 602 is configured to select a scanning order corresponding to the above-mentioned texture from preset candidate scanning orders; the above-mentioned preset candidate scanning orders include scanning orders other than the zigzag scanning order;

The first processing unit 603 is configured to perform rate-distortion optimization processing on the preset zigzag scanning order and the selected scanning order to obtain the preferred scanning order;

The first resetting unit 604 is configured to reset the transformation coefficient block of the block to be encoded to the transformation coefficient block scanned according to the predetermined regular scanning order if the above-mentioned preferred scanning order is other than the zigzag scanning order;

The first scanning unit 605 is configured to scan the transformation coefficient blocks of the block to be coded according to the preferred scanning order if the preferred scanning order is the Z-shaped scanning order; if the above-mentioned preferred scanning order is other than the Z-shaped scanning order, then Scanning the reset transform coefficient blocks of the block to be encoded according to the scanning order of the predetermined rules;

The first encoding unit 606 is configured to encode indication information indicating whether the scanning order used for scanning is a zigzag scanning order into the code stream.

A scanning device for transform coefficient blocks, as shown in Figure 7, comprising:

The second parsing unit 701 is configured to parse the code stream to obtain indication information;

The second detection unit 702 is configured to detect the texture of the encoded or decoded block as a reference of the block to be decoded if the received indication information of the code stream indicates that the scanning order is not a zigzag scanning order, and the texture reflects the above-mentioned to-be-decoded Transformation coefficients of a block The change law of the transformation coefficients of the block in each direction;

The second selection unit 703 is configured to select a scanning order corresponding to the above-mentioned texture from preset candidate scanning orders; the above-mentioned preset candidate scanning orders include scanning orders other than the zigzag scanning order;

The second scanning unit 704 is configured to scan the transform coefficient blocks of the block to be decoded according to a scanning order of predetermined rules;

The second reset unit 705 is configured to reset the transform coefficient blocks of the block to be decoded according to the selected scanning order and the scanning order of the predetermined rule after the scanning is completed if the selected scanning order is different from the scanning order of the predetermined rule is a block of transform coefficients that can be scanned in the selected scan order.

A scanning device for transform coefficient blocks, as shown in Figure 8, comprising:

The third detection unit 801 is configured to detect the texture of the coded block as a reference of the block to be coded, the above texture embodies the change law of the transformation coefficient of the transformation coefficient block of the above-mentioned block to be coded in each direction;

The third selection unit 802 is configured to select a scanning order corresponding to the above-mentioned texture from preset candidate scanning orders; the above-mentioned preset candidate scanning orders include Z-shaped scanning orders and other scanning orders other than Z-shaped scanning orders;

The third resetting unit 803 is configured to reset the transformation coefficient block of the block to be encoded to a transformation coefficient block conforming to the Z-shape scanning order if the selected scanning order is a scanning order other than the Z-shape scanning order;

The third scanning unit 804 is configured to scan the transform coefficient block of the block to be encoded according to the Z-shaped scanning order if the selected scanning order is the Z-shaped scanning order; or, to scan the reset above-mentioned The transform coefficient blocks of the block to be coded are scanned.

A scanning device for transform coefficient blocks, as shown in Figure 9, comprising:

The fourth detection unit 901 is configured to detect the texture of the decoded block as a reference of the block to be decoded, and the texture reflects the change rule of the transform coefficient block in each direction of the transform coefficient block of the block to be decoded;

The fourth selection unit 902 is configured to select a scanning order corresponding to the above-mentioned texture from preset candidate scanning orders; the above-mentioned preset candidate scanning orders include Z-shaped scanning orders and other scanning orders other than Z-shaped scanning orders;

The fourth reset unit 903 is configured to reset the transformation coefficient block of the block to be decoded from the transformation coefficient block conforming to the Z-shape scanning order to complying with the above selection if the selected scanning order is other than the Z-shape scanning order Transform coefficient blocks in scan order;

The fourth scanning unit 904 is configured to scan the transformation coefficient block of the block to be decoded according to the zigzag scanning order if the selected scanning order is the zigzag scanning order; The transform coefficient blocks of the block to be coded are scanned.

The scheme of the above-mentioned device only needs to choose between the horizontal and vertical scanning order and the Z-shaped scanning order, which is an alternative choice, compared to horizontal, vertical and Z-shaped scanning order (zig-zag) The choice of one of the three choices can use one less bit to carry the selected information, so when it is encoded into the encoding header information, it will save resources; in addition, it is more efficient when selecting.

A scanning method of a transform coefficient block, the solution of this embodiment can be executed at the encoding end, as shown in Figure 10, including:

1001: Detect the texture of the coded block used as a reference of the block to be coded, the above texture embodies the change rule of the transformation coefficient block in each direction of the transformation coefficient block of the above-mentioned block to be coded;

The above 1001 belongs to a kind of physical derivation. The coded texture used as a reference is similar to the texture of the current block to be coded, and the texture to be coded is similar to the residual texture to be coded. The distribution law of the transformation coefficient is closely related to the residual texture relevant. More specifically, the above-mentioned textures include horizontal textures, vertical textures and oblique textures; the oblique textures can also be regarded as no textures.

More specifically, the above-mentioned detection of the texture of the decoded block includes:

When performing inter-frame decoding, calculate the horizontal gradient value in the horizontal direction and the vertical gradient value in the vertical direction of the transform coefficient block; the horizontal gradient value is the sum of the absolute values of the differences between adjacent pixels in the horizontal direction , the vertical gradient value is the sum of the absolute values of the differences between adjacent pixel points in the vertical direction; the above-mentioned transform coefficient block as a reference is the change coefficient block of the above-mentioned decoded block;

If the horizontal gradient value is greater than N times the vertical gradient value, the texture is determined to be a vertical texture, and the vertical gradient value is greater than N times the horizontal gradient value, then the texture is determined to be a horizontal texture, otherwise it is determined that the texture is an oblique texture; the above N is the first The preset value, N can be determined by the resolution width, for example, N=2 when the resolution width is greater than 1000, and N=1.5 when the resolution width is less than 1000; The embodiment of the invention does not limit this.

When performing intra-frame decoding, if the vertical offset of the intra-frame prediction mode direction is within M, the texture is determined to be a vertical texture, and the horizontal offset of the intra-frame prediction mode direction is within M, then the texture is determined It is a horizontal texture, otherwise it is determined that the texture is an oblique texture; the above M is the second preset value, M can also be determined by the resolution width, for example, set to 5, and can also be set to other values such as 3, 4, etc. The embodiments of the invention are not limited.

Further, the embodiment of the present invention also provides an implementation method of modifying the preset value: if the ratio of the horizontal texture to the vertical texture exceeds the third preset value in the decoded block, then reduce the value of N; if the ratio of the horizontal texture to the vertical texture If the ratio of straight texture is less than N, increase the value of N. The third preset value can be obtained in the following manner. By performing intra-frame coding on the sequence of transform coefficients with different characteristics, and statistically calculating the proportional relationship between the horizontal and vertical prediction directions, the proportional relationship can be used as the third preset value.

Optionally, if there is an encoded block or a decoded block, then the texture of the encoded block or decoded block is known, and this information can be used to reduce the amount of computation; the above detection of the texture of the transform coefficient block includes: detecting the texture to be decoded The block sets the texture of the coded block or decoded block within the temporal or spatial distance, and determines the detected texture as the texture of the transform coefficient block.

1002: If the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, reset the residual data block of the block to be encoded so that the corresponding transformation coefficient block is a transformation coefficient block scanned according to the predetermined rule;

The scanning order corresponding to the above textures includes as shown in Figure 2A to Figure 2C: vertical texture corresponds to the horizontal scanning order of progressive scanning, horizontal texture corresponds to the vertical scanning order of column-by-column scanning, and oblique texture corresponds to the Z-shaped sequential scanning. shape scan order. 2A to 2C take a 4X4 matrix as an example, where the circle represents the transformation coefficient, the value under the circle represents the coordinate (ie position) of the transformation coefficient, and the direction of the arrow represents the scanning direction, that is, the scanning order. It should be noted that the matrix on the left side of Figure 2C and the matrix on the right represent a Z-shaped scanning order, and the Z-shaped scanning order can be customized, so there are many possible types, and the examples in Figure 2C are not exhaustive; therefore, this paper The embodiment of the invention does not limit the order of the zigzag scanning.

1003: Perform rate-distortion optimization processing on the preset zigzag scanning order and the predetermined regular scanning order to obtain the optimal scanning order;

More specifically, in the above step 1003, if the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, the residual data block of the block to be encoded is reset so that the corresponding transform coefficient block is scanned according to the predetermined rule The transformation coefficient block of the block; scanning the transformation coefficient block of the block to be coded according to the scanning order of the predetermined rules includes:

If the preferred scanning order is the first scanning order, the residual data block of the block to be encoded is transposed, and the transposed transform coefficient block of the block to be encoded is scanned according to the second scanning order; the above-mentioned first scanning order The scan order is symmetrical to the scan order of the second scan order;

If the preferred scanning order is the second scanning order, the transform coefficient blocks of the block to be encoded are scanned according to the second scanning order.

It should be noted that the above "first" and "second" are used to distinguish two scanning sequences with a symmetrical relationship, and there is no other limitation. For example, there are two symmetrical scanning sequences between the horizontal scanning sequence and the vertical scanning sequence. The scanning order, if the first scanning order is a horizontal scanning order, then the second scanning order is a vertical scanning order, and if the first scanning order is a vertical scanning order, then the second scanning order is a horizontal scanning order.

More specifically, in the above step 1003, the residual data block of the block to be encoded is made such that the corresponding transform coefficient block is a transform coefficient block scanned according to the scanning order of the predetermined rule; The scanning of the transformation coefficient block includes: making the residual data block of the block to be encoded, making the corresponding transformation coefficient block a transformation coefficient block scanned according to the scanning order of the predetermined rule; scanning the block to be encoded according to the scanning order of the predetermined rule The transform coefficient blocks are scanned. If this method is adopted, the indication information in step 1005 may not be transmitted, which will be described in detail in subsequent embodiments.

1004: Scan the transform coefficient blocks of the block to be encoded according to the preferred scanning order;

1005: Encode the indication information indicating whether the scanning sequence used for scanning is a zigzag scanning sequence into the code stream.

In the above implementation mode, it is only necessary to choose between the predetermined scanning order and the Z-shaped scanning order, which is a choice of one of two choices. Compared with the choice of one of three choices, one less bit can be used to carry the selected information. Therefore, in the future When encoding header information, it will save resources; in addition, it will be more efficient when selecting. In addition, by transposing the transform coefficient matrix, multiplexing the same entropy coding model can improve the coding efficiency.

More specifically, this embodiment also provides an example of an implementation manner of presetting the candidate scanning order. The above preset candidate scanning order includes:

Pre-defined scanning rules, which determine the order of scanning; or, pre-count the number of non-zero transform coefficients at each position of two or more transform coefficient blocks, and arrange each non-zero For the positions of the transform coefficients corresponding to the number of times, the order of the positions of the transform coefficients obtained by arranging is determined as a preset candidate scanning order.

The embodiment of the present invention gives an example in the latter implementation of the above example of the preset candidate scanning mode: In the encoder, according to the texture of the residual block, the quantization residual can be divided into three categories: horizontal texture The corresponding quantized residual, the quantized residual corresponding to the vertical texture, and the quantized residual corresponding to the oblique texture; the way to determine the scanning order is to establish a counter group with the same number of transform coefficients (for example, 4x4 transform is 16 counters) , and then use the counter to count, specifically: judge whether each transform coefficient is zero, if it is not zero, then add one to the counter at the corresponding position; after the number of detected transform coefficient blocks reaches the set number, each counter has its own The value of the count; at this time, the values of each counter can be arranged in descending order, and the order of the positions of the above-mentioned transformation coefficients obtained by the arrangement can be determined as the preset candidate scanning order. Using this method, when scanning is performed according to the obtained order, the position of the transformation coefficient corresponding to the counter with a large value will be arranged at the front in the scanning order.

Example scheme 1. The following is a specific description of the scanning link in the encoding process:

A: Encode according to the encoding process until the transformation coefficient encoding is performed;

B: If inter-frame coding (Inter) is performed, the texture of the reference block is detected to obtain its texture (horizontal Hor texture, vertical ver texture, oblique texture); if intra-frame coding (Intra) is performed In some cases, if the direction of the intra prediction mode (ipmode) is ver+/-5, the texture is a vertical texture, the direction is Hor+/-5, and the texture is a horizontal texture, and in other cases it is an oblique texture. The offset set in this embodiment is 5, of course, it can also be set to other values, which is not limited in this embodiment of the present invention. A scanning order corresponding to the above texture is selected from preset candidate scanning orders according to the obtained texture.

The detection method in the above B can be:

B1: Determine the detection step size. This step sets different detection steps for different transformation units (Transform Unit, TU). For example, when TU=4, the step size is 1, when TU=8, the step size is 1, and when TU=16, the step size is 2. When TU=32, the step size is 4, or the corresponding step size of all sizes of TUs is 1; if all sizes of TUs use the same step size, then the step B1 can be omitted.

B2: In the reference block (that is, the transform coefficient block used as a reference), the difference value is calculated for every two pixels of adjacent detection steps in the horizontal direction; the absolute value of the accumulated difference value is obtained to obtain the horizontal gradient value;

B3: Calculate the difference between every two pixels of the adjacent detection step in the vertical direction in the reference block; accumulate the absolute value of the difference to obtain the vertical gradient value;

B4: If the horizontal gradient value is greater than N times the vertical gradient value, then determine its texture as vertical texture; if the vertical gradient value is greater than N times the horizontal gradient value, determine its texture as horizontal texture; otherwise it is oblique texture ; After B4, it is also possible to further judge whether the threshold N needs to be updated according to the proportion distribution of horizontal, vertical and oblique textures in the coded block. The judgment method is to judge whether the ratio of the horizontal gradient value to the vertical gradient value exceeds the preset value , if yes, increase the preset value, otherwise, decrease the preset value. (wherein the preset value is obtained by the following method, by performing intra-frame coding on the sequence of transform coefficients with different characteristics, and statistically calculating the proportional relationship between the horizontal and vertical prediction directions, the proportional relationship can be used as the preset value. Step C is to preset An automatic correction process of setting values, which is not a mandatory step.

In addition, for the method of step B detection in the above encoding process, there may be an alternative solution: detect the texture of the encoded block or decoded block within the set time domain or spatial domain distance of the block to be decoded, and determine the detected texture as the The texture of the transform coefficient block for the decoded block. More specifically, for example, the texture of the decoded block surrounding (upper, left, upper left, upper right, lower left) of the block to be decoded is detected as the texture of the transform coefficient block of the current block to be decoded.

C: If the scanning order corresponding to the texture is vertical, transpose the transformation coefficient; if the scanning order corresponding to the texture is horizontal, continue;

D: performing rate-distortion optimization processing on the preset zigzag scanning sequence and the scanning sequence of predetermined rules to obtain the optimal scanning sequence;

E: Encode and scan the transformation coefficient blocks to be scanned according to the preferred scanning order and related entropy coding model, and then continue the subsequent coding process;

F: Encoding the indication information indicating whether the scanning sequence used for scanning is a zigzag scanning sequence into the code stream. This step can be performed during the execution of step E. It can be understood that, after the encoding is completed, the encoding result (code stream) will be sent to the decoding end, which will not be described in other places in this embodiment of the present invention.

Correspondingly, the embodiment of the present invention also provides a scanning method for transform coefficient blocks performed at the decoding end, as shown in FIG. 11 , including:

1301: Analyze the code stream to obtain instruction information;

1302: Scan and inversely transform the transformation coefficient blocks of the block to be decoded according to the scanned scanning sequence;

1303: If the indication information of the code stream indicates that the scanning order is not zigzag scanning, then detect the texture of the decoded block as a reference of the block to be decoded, the texture reflects the transformation coefficient block of the block to be decoded in each direction Variation rules of up-conversion coefficients; in this embodiment, the scanning sequence corresponding to the above-mentioned texture includes scanning sequences other than the Z-shaped scanning sequence;

1304: If the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, according to the scanning order corresponding to the texture and the scanning order of the predetermined rule, convert the residual data block of the block to be decoded Reset so that the corresponding transform coefficient block is a transform coefficient block that can be scanned according to a scanning order of a predetermined rule. It can be understood that this embodiment corresponds to the encoding end, so the residual data block of the block to be decoded has been reset by the encoding end according to the above predetermined rules.

More specifically, the transform coefficient blocks of the block to be decoded are scanned according to the scanning order of the predetermined rule; if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, The corresponding scanning order and the scanning order of the predetermined rule reset the residual data block of the block to be decoded, so that the corresponding transform coefficient block is a transform coefficient block that can be scanned according to the predetermined rule of scanning order, including:

If the selected scanning order is the first scanning order, scan the transform coefficient block of the block to be decoded according to the second scanning order; after the scanning is completed, the residual data block of the block to be decoded is transposed; the first scanning order and the second The scanning order of the scanning order is symmetrical, and the second scanning order is the scanning order of the aforementioned predetermined rule.

Example 2: The decoding process is similar to the scanning method of the encoding process:

A: Decode according to the decoding process until the transformation coefficient analysis is performed;

B: Parse the code stream to obtain instruction information, which is the instruction information in step H of the encoding process;

C: Analyze, scan, and inversely transform the transformation coefficient blocks to be scanned according to the analyzed scanning order and the relevant entropy coding model;

D: Determine whether the instruction information indicates that the scanning sequence is a Z-scanning sequence. If it is not a Z-scanning sequence, you can refer to step B of Example Scheme 1, according to the obtained texture direction. If the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, transpose the residual data block of the block to be decoded;

E: Continue the subsequent decoding process.

The above examples of schemes 1 and 2 only need to choose between the horizontal and vertical scanning order and the Z-shaped scanning order, which is a choice between the two, compared to the horizontal, vertical and Z-shaped scanning order (zig-zag ) can use one less bit to carry the selected information, so when it is encoded into the encoding header information, it will save resources; in addition, it is more efficient when selecting.

The embodiment of the present invention also provides another scanning method for the transform coefficient block, which is implemented in the coding device, and further improves the coding efficiency without transmitting instruction information on the basis of the above two solutions; As shown in Figure 12, including:

1401: Detect the texture of the coded block used as a reference of the block to be coded, the above texture embodies the change rule of the transformation coefficient block in each direction of the transformation coefficient block of the above-mentioned block to be coded;

1402: If the scanning order corresponding to the texture is inconsistent with the scanning order of the predetermined rule, reset the residual data block of the block to be encoded so that the corresponding transformation coefficient block is a transformation coefficient block scanned according to the predetermined rule;

1403: Scan the transform coefficient blocks of the to-be-encoded block according to a predetermined scanning order.

Example scheme 1. The following is a specific description of the scanning link in the encoding process:

The following is a specific description of the scanning link in the encoding process:

A: Encode according to the encoding process until the transformation coefficient encoding is performed;

B: For this step, you can refer to Step B of Example Scheme 1 to obtain the texture direction;

C: According to the selected scan order, reset the position of the transformation coefficients to conform to the positional relationship of the zigzag scan order;

D: Encoding and scanning the transformation coefficient blocks to be scanned according to the zigzag scanning sequence and the related entropy coding model, and then continue the subsequent coding process.

Correspondingly, the embodiment of the present invention also provides another scanning method for transform coefficient blocks. This solution is implemented in the decoding device, without transmitting instruction information, and can further improve the coding efficiency; as shown in FIG. 13 , it includes:

1501: Scan the transform coefficient block of the block to be decoded according to the scanning order of the predetermined rule;

1502: Detect the texture of the decoded block used as a reference of the block to be decoded, where the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

1503: If the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, according to the scanning order corresponding to the texture and the scanning order of the predetermined rule, convert the residual data block of the block to be decoded to Reset so that the corresponding transform coefficient block is a transform coefficient block that can be scanned according to a scanning order of a predetermined rule.

The corresponding decoding process is similar to the scanning method of the encoding process:

A: Decode according to the decoding process until the transformation coefficient analysis is performed;

B: Analyzing, scanning, and inverse transforming the transformation coefficient blocks to be scanned according to the Z-shaped scanning sequence and the relevant entropy coding model;

C: In this step, you can refer to step B of Example Scheme 1 to obtain the texture direction; if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, transpose the residual data block of the block to be decoded

D: continue the subsequent decoding process;

The texture detection and transposition operations are performed after the inverse transformation operation, which will not affect the parallelism of decoding, reduce the processing delay, and improve the decoding efficiency.

A scanning device for transform coefficient blocks, as shown in Figure 14, comprising:

The fifth detection unit 1601 is configured to detect the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transformation coefficient of the transformation coefficient block of the block to be coded in each direction;

The fifth resetting unit 1602 is configured to reset the residual data block of the block to be coded so that the corresponding transform coefficient block is according to the predetermined rule if the scanning order corresponding to the texture is not consistent with the predetermined rule. Scanned transform coefficient block;

The fifth processing unit 1603 is configured to perform rate-distortion optimization processing on the preset zigzag scanning order and the scanning order of predetermined rules to obtain the preferred scanning order;

The fifth scanning unit 1604 is configured to scan the transformation coefficient blocks of the block to be encoded according to the preferred scanning order;

The fifth encoding unit 1605 is configured to encode indication information indicating whether the scanning order used for scanning is a zigzag scanning order into the code stream.

A scanning device for transform coefficient blocks, as shown in Figure 15, comprising:

A sixth parsing unit 1701, configured to parse the code stream to obtain indication information;

The sixth scanning unit 1702 is configured to scan the transform coefficient blocks of the block to be decoded according to the analyzed scanning order;

The sixth detection unit 1703 is configured to detect the texture of the decoded block as a reference of the block to be decoded if the indication information of the code stream indicates that the scanning order is not Z-scan, and the texture reflects the texture of the block to be decoded The change law of the transform coefficients of the transform coefficient block in each direction;

The sixth reset unit 1704 is configured to, if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, the scanning order corresponding to the texture and the scanning order of the predetermined rule will be The residual data block of the decoded block is reset, so that the corresponding transform coefficient block is a transform coefficient block that can be scanned according to a predetermined scanning order.

A scanning device for transform coefficient blocks, as shown in Figure 16, comprising:

The seventh detection unit 1801 is configured to detect the texture of the coded block as a reference of the block to be coded, the texture embodies the change law of the transformation coefficient of the transformation coefficient block in each direction of the block to be coded;

The seventh resetting unit 1802 is configured to reset the residual data block of the block to be coded so that the corresponding transform coefficient block is according to the predetermined rule if the scanning order corresponding to the texture is not consistent with the predetermined rule. Scanned transform coefficient block;

The seventh scanning unit 1803 is configured to scan the transform coefficient blocks of the block to be coded according to the scanning sequence of predetermined rules;

A scanning device for transform coefficient blocks, as shown in Figure 17, comprising:

An eighth scanning unit 1901, configured to scan the transform coefficient blocks of the block to be decoded according to a scanning sequence of predetermined rules;

The eighth detection unit 1902 is configured to detect the texture of the decoded block as a reference of the block to be decoded, and the texture embodies the change rule of the transform coefficient of the transform coefficient block of the block to be decoded in each direction;

The eighth reset unit 1903 is configured to, if the scanning order corresponding to the texture is different from the scanning order of the predetermined rule, after the inverse transformation is completed, the scanning order corresponding to the texture and the scanning order of the predetermined rule will be The residual data block of the decoded block is reset, so that the corresponding transform coefficient block is a transform coefficient block that can be scanned according to a predetermined scanning order.

The method provided by the embodiment of the present invention can be applied in the field of digital signal processing and realized by a video encoder and a decoder. Video encoders and decoders are widely used in various communication equipment or electronic equipment, such as: media gateways, mobile phones, wireless devices, personal data assistants (PDA), handheld or portable computers, GPS receivers/navigators, cameras , video players, cameras, video recorders, surveillance equipment and more. Such devices include processors, memory, and interfaces for transmitting data. The video codec can be implemented directly by a digital circuit or chip such as a DSP (digital signal processor), or by software code driving a processor to execute a process in the software code.

Those of ordinary skill in the art can understand that all or part of the steps in the method of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the above-mentioned program can be stored in a computer-readable storage medium, the above-mentioned storage medium It can be read-only memory, disk or CD-ROM, etc.

The method, device and system for scanning transform coefficient blocks provided by the embodiments of the present invention are described above in detail. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The descriptions of the above embodiments are only used To help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification does not It should be understood as a limitation of the present invention.

Claims (8)

1. A method for scanning transform coefficient blocks, comprising: Detecting the texture of the coded block used as a reference of the block to be coded, the texture embodies the change law of the transform coefficient of the transform coefficient block of the block to be coded in each direction; Selecting a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include scan orders other than the zigzag scan order; Performing rate-distortion optimization processing on the Z-shaped scanning order and the selected scanning order to obtain the preferred scanning order; If the preferred scanning order is a zigzag scanning order, then scan the transform coefficient blocks of the block to be encoded according to the preferred scanning order; If the preferred scanning order is a scanning order other than the zigzag scanning order, reset the transform coefficient block of the block to be coded to be the transform coefficient block scanned according to the scanning order of the predetermined rule; Scanning the reset transform coefficient block of the block to be encoded; Indicating whether the scanning sequence used for scanning is a zigzag scanning sequence is encoded into the code stream. 2. The method according to claim 1, wherein if the preferred scanning order is a scanning order other than the zigzag scanning order, the transform coefficient block of the block to be encoded is reset to scan according to a predetermined rule Sequentially scanned transform coefficient blocks; scanning the reset transform coefficient blocks of the block to be encoded according to the scanning order of the predetermined rule includes: If the preferred scanning order is the first scanning order, the transform coefficients of the block to be encoded are transposed, and the transposed transform coefficient blocks of the block to be encoded are scanned according to the second scanning order; the first scanning order The scan order is symmetrical to the scan order of the second scan order; If the preferred scanning order is the second scanning order, the transform coefficient blocks of the block to be encoded are scanned according to the second scanning order. 3. The method according to claim 1 or 2, wherein detecting the texture of the coded block comprises: When performing inter-frame encoding, calculate the horizontal gradient value in the horizontal direction and the vertical gradient value in the vertical direction of the encoded block; the horizontal gradient value is the sum of the absolute values of the differences between adjacent pixels in the horizontal direction , the vertical gradient value is the sum of the absolute values of the differences between adjacent pixels in the vertical direction; If the horizontal gradient value is greater than the vertical gradient value of N times, then it is determined that the texture is a vertical texture, and the vertical gradient value is greater than the horizontal gradient value of N times, then it is determined that the texture is a horizontal texture, otherwise it is determined that the texture is an oblique texture; a preset value; When performing intra-frame coding, if the vertical offset of the intra-frame prediction mode direction is within M, the texture is determined to be a vertical texture, and the horizontal offset of the intra-frame prediction mode direction is within M, then the texture is determined is a horizontal texture, otherwise it is determined that the texture is an oblique texture; the M is a second preset value. 4. A method for scanning transform coefficient blocks, comprising: Analyzing the code stream to obtain indication information, if the received indication information of the code stream indicates that the scanning order is not a zigzag scanning order, then detecting the texture of the decoded block as a reference of the block to be decoded, the texture embodies the block to be decoded The changing law of the transform coefficients of the transform coefficient block in each direction; Selecting a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include scan orders other than the zigzag scan order; Scanning the transform coefficient blocks of the block to be decoded according to the scanning order of predetermined rules; If the selected scanning order is different from the scanning order of the predetermined rule, after the scanning is completed, the transform coefficient blocks of the block to be decoded are reset to follow the selected scanning order according to the selected scanning order and the scanning order of the predetermined rule Scanned block of transform coefficients. 5. The method according to claim 4, wherein the transform coefficient blocks of the block to be decoded are scanned according to the scanning order of the predetermined rule; if the selected scanning order is different from the scanning order of the predetermined rule, then the After the completion, according to the selected scanning order and the scanning order of the predetermined rules, resetting the transform coefficient block of the block to be decoded as a transform coefficient block that can be scanned according to the selected scanning order includes: If the selected scanning order is the first scanning order, scan the transformation coefficient block of the block to be decoded according to the second scanning order; after the scanning is completed, transpose the transformation coefficient block of the block to be decoded; the first scanning order and the second scanning order The scanning sequences of the two scanning sequences are symmetrical, and the second scanning sequence is the scanning sequence of the predetermined rule. 6. The method according to claim 4 or 5, wherein detecting the texture of the decoded block comprises: When performing inter-frame decoding, calculate the horizontal gradient value in the horizontal direction and the vertical gradient value in the vertical direction of the decoded block; the horizontal gradient value is the sum of the absolute values of the differences between adjacent pixels in the horizontal direction , the vertical gradient value is the sum of the absolute values of the differences between adjacent pixels in the vertical direction; If the horizontal gradient value is greater than the vertical gradient value of N times, then it is determined that the texture is a vertical texture, and the vertical gradient value is greater than the horizontal gradient value of N times, then it is determined that the texture is a horizontal texture, otherwise it is determined that the texture is an oblique texture; a preset value; When performing intra-frame decoding, if the vertical offset of the intra-frame prediction mode direction is within M, the texture is determined to be a vertical texture, and the horizontal offset of the intra-frame prediction mode direction is within M, then the texture is determined is a horizontal texture, otherwise it is determined that the texture is an oblique texture; the M is a second preset value. 7. A scanning device for transform coefficient blocks, comprising: The first detection unit is configured to detect the texture of the coded block as a reference of the block to be coded, the texture embodies the change law of the transformation coefficient of the transformation coefficient block in each direction of the block to be coded; A first selection unit, configured to select a scan order corresponding to the texture from preset candidate scan orders; the preset candidate scan orders include scan orders other than the zigzag scan order; The first processing unit is configured to perform rate-distortion optimization processing on the zigzag scanning order and the selected scanning order to obtain the preferred scanning order; A first resetting unit, configured to reset the transformation coefficient block of the block to be coded to the transformation coefficient block scanned according to a predetermined scanning order if the preferred scanning order is other than the zigzag scanning order; The first scanning unit is configured to scan the transformation coefficient blocks of the block to be coded according to the preferred scanning order if the preferred scanning order is a zigzag scanning order; if the preferred scanning order is a scanning order other than the zigzag scanning order, then Scanning the reset transform coefficient blocks of the block to be encoded according to the scanning order of the predetermined rule; The first encoding unit is configured to encode indication information indicating whether the scanning order used for scanning is a zigzag scanning order into the code stream. 8. A scanning device for transform coefficient blocks, comprising: The second parsing unit is used to parse the code stream to obtain indication information; The second detection unit is configured to detect the texture of the decoded block as a reference of the block to be decoded if the received indication information of the code stream indicates that the scan order is not a zigzag scan order, and the texture embodies the block to be decoded The changing law of the transform coefficients of the transform coefficient block in each direction; The second selection unit is configured to select a scanning order corresponding to the texture from preset candidate scanning orders; the preset candidate scanning orders include scanning orders other than the zigzag scanning order; The second scanning unit is configured to scan the transform coefficient blocks of the block to be decoded according to a scanning order of predetermined rules; The second resetting unit is used to reset the transform coefficient block of the block to be decoded according to the selected scanning order and the scanning order of the predetermined rule after the scanning is completed if the selected scanning order is different from the scanning order of the predetermined rule. Set to a block of transform coefficients that can be scanned in the selected scan order.