WO2012093491A1

WO2012093491A1 - Dynamic picture image encoding method and device, and dynamic picture image decoding method and device

Info

Publication number: WO2012093491A1
Application number: PCT/JP2011/050197
Authority: WO
Inventors: 沙織浅香; 隆志渡辺; 昭行谷沢
Original assignee: 株式会社東芝
Priority date: 2011-01-07
Filing date: 2011-01-07
Publication date: 2012-07-12

Abstract

According to an embodiment, this dynamic picture image encoding device includes a loop filter processor, a generator, a derivation unit, a deblocking filter processor, and an encoder. The loop filter processor performs a loop filter process according to loop filter information. The generator sets one of a plurality of conversion processes according to the loop filter information, and generates conversion process information indicative of the conversion process that has been set. The derivation unit performs, on the basis of quantization information, the conversion process that has been specified by the conversion process information, and derives a filter control parameter. The deblocking filter processor performs a deblocking filter process according to the filter control parameter. The encoder encodes at least the loop filter information and the quantization information.

Description

Moving picture encoding method and apparatus, moving picture decoding method and apparatus

Embodiment relates to deblocking filter processing.

Generally, various filter processes are performed in the process of encoding and decoding moving images. For example, a deblocking filter (DF) process may be performed to reduce block distortion of a (local) decoded image. Further, an adaptive loop filter (ALF) process may be performed to reduce the coding distortion of the decoded image. Specifically, the encoding side sets application / non-application of filter processing and information indicating the filter coefficient (loop filter information) and transmits the information to the decoding side, and the decoding side performs ALF processing using the loop filter information. Do. Furthermore, both deblocking filter processing and ALF processing may be mixed.

Usually, in deblocking filter processing, application / non-application of filter processing, strength or type of applied filter processing, and the like are controlled in accordance with predetermined filter control parameters, pixel values of a target image, prediction mode, and the like. However, even when the deblocking filter process and the ALF process are mixed, the deblocking filter process is controlled independently. That is, the influence of the ALF process is not considered in the control of the deblocking filter process. For example, when the ALF process is applied to the application target of the deblocking filter process, the decoded image tends to be blurred. On the other hand, when the ALF process is not applied to the application target of the deblocking filter process, the deblocking filter process is required to sufficiently reduce the coding distortion of the decoded image alone.

Embodiment is aimed at effective control of deblocking filter processing.

According to the embodiment, the moving image encoding apparatus includes a loop filter processing unit, a generation unit, a derivation unit, a deblocking filter processing unit, and an encoding unit. The loop filter processing unit performs loop filter processing according to the loop filter information. The generation unit sets one of a plurality of conversion processes according to the loop filter information, and generates conversion process information indicating the set conversion process. The derivation unit performs a conversion process specified by the conversion process information based on the quantization information, and derives a filter control parameter. A deblocking filter process part performs a deblocking filter process according to a filter control parameter. The encoding unit encodes at least loop filter information and quantization information.

1 is a block diagram illustrating a moving image encoding apparatus according to a first embodiment. The block diagram which shows the modification of the moving image encoder of FIG. The block diagram which illustrates the parameter derivation part of Drawing 1. 3 is a flowchart illustrating a part of the operation of the moving image encoding apparatus in FIG. 1. Explanatory drawing of two types of conversion tables. Explanatory drawing of two types of conversion tables. 1 is a block diagram illustrating a video decoding device according to a first embodiment. The block diagram which shows the modification of the moving image decoding apparatus of FIG. The block diagram which illustrates the moving picture coding device concerning a 2nd embodiment. 10 is a flowchart illustrating a part of the operation of the video decoding apparatus in FIG. 9. The block diagram which illustrates the moving picture decoding device concerning a 2nd embodiment. Explanatory drawing of a deblocking filter process. Explanatory drawing of a deblocking filter process.

Hereinafter, embodiments will be described with reference to the drawings. In each embodiment, the same or similar elements as those already described are denoted by the same or similar reference numerals, and redundant description is basically omitted.

(First embodiment)
(Moving picture encoding device)
As shown in FIG. 1, the moving image encoding apparatus according to the first embodiment includes an encoding unit 113, an encoding control unit 114, and a multiplexer 112. The encoding unit 113 encodes the input image (signal) 11 and obtains encoded data 25. The encoding unit 113 includes a subtractor 101, a transform / quantization unit 102, an inverse quantization / inverse transform unit 103, an adder 104, a deblocking filter processing unit 105, a loop filter processing unit 106, a frame memory 107, and a prediction unit 108. A conversion processing setting unit 109, a parameter deriving unit 110, and an entropy encoding unit 111.

The subtracter 101 takes in the input image 11 from the outside, and inputs a predicted image (signal) 24 corresponding to the input image 11 from the prediction unit 108. The subtracter 101 subtracts the predicted image 24 from the input image 11 to obtain a prediction error (signal) 12. The subtractor 101 outputs the prediction error 12 to the transform / quantization unit 102.

The transform / quantization unit 102 inputs the prediction error 12 from the subtractor 101. The transform / quantization unit 102 performs predetermined transform processing and quantization processing on the prediction error 12 to obtain a quantized transform coefficient (hereinafter referred to as a quantized transform coefficient) 13. The predetermined transformation process is orthogonal transformation such as discrete cosine transformation (DCT), for example. The transform / quantization unit 102 receives quantization information 18 (for example, a quantization parameter QP), which will be described later, from the encoding control unit 114, and performs quantization processing in accordance therewith. Furthermore, the transform / quantization unit 102 may perform a quantization process according to offset information 19 described later. The transform / quantization unit 102 outputs the quantized transform coefficient 13 to the inverse quantization / inverse transform unit 103 and the entropy encoder 111.

The inverse quantization / inverse transform unit 103 receives the quantized transform coefficient 13 from the transform / quantization unit 102. The inverse quantization / inverse transform unit 103 performs a predetermined inverse quantization process and inverse transform process on the quantized transform coefficient 13 to restore the prediction error (signal) 14. The predetermined inverse quantization process and inverse transform process are inverse processes of the transform process and the quantization process in the transform / quantization unit 102. The inverse quantization / inverse transform unit 103 receives the quantization information 18 from the encoding control unit 114 and performs an inverse quantization process according to the input. Further, the inverse quantization / inverse transform unit 103 may perform an inverse quantization process according to offset information 19 described later. The inverse quantization / inverse transform unit 103 outputs the prediction error 14 to the adder 104.

The adder 104 inputs the prediction error 14 from the inverse quantization / inverse transform unit 103, and inputs the predicted image 24 from the prediction unit 108. The adder 104 adds the prediction error 14 and the prediction image 24 to obtain a locally decoded image (signal) 15. The adder 104 outputs the locally decoded image 15 to the deblocking filter processing unit 105.

The deblocking filter processing unit 105 inputs the local decoded image 15 from the adder 104 and inputs a filter control parameter 20 described later from the parameter deriving unit 110. The deblocking filter processing unit 105 performs deblocking filtering on the local decoded image 15 (its block boundary) according to the filter control parameter 20 to obtain a filtered image (signal) 21. The deblocking filter processing unit 105 outputs the filtered image 21 to the loop filter processing unit 106.

The loop filter processing unit 106 inputs the filtered image 21 from the deblocking filter processing unit 105 and inputs the loop filter information 16 from the encoding control unit 114. The loop filter processing unit 106 performs loop filter processing on the filtered image 21 (block) according to the loop filter information 16 to obtain a restored image (signal) 22. The loop filter information 16 can include information indicating application / non-application of loop filter processing and filter coefficients. The loop filter processing unit 106 stores the restored image 22 in the frame memory 107.

The frame memory 107 stores the restored image 22 from the loop filter processing unit 106 as a reference image (signal) 23. The reference image 23 is read by the prediction unit 108 as necessary.

The prediction unit 108 reads the reference image 23 from the frame memory 107. The prediction unit 108 performs a prediction process (for example, an intra prediction process or an inter prediction process) based on the reference image 23 to obtain a predicted image 24. The prediction unit 108 outputs the predicted image 24 to the subtracter 101 and the adder 104, respectively.

The encoding control unit 114 performs overall control of the encoding unit 113. Specifically, the encoding control unit 114 controls the generated code amount (so-called rate control) through feedback control of the generated code amount and control of the quantization characteristic. The control of the quantization characteristic includes setting the quantization information 18 and the offset information 19. Further, the encoding control unit 114 controls application / non-application of the loop filter processing by the loop filter processing unit 106 and sets the loop filter information 16. Also, the encoding control unit 114 may perform control of the prediction unit 108 (for example, selection of a prediction mode).

The encoding control unit 114 outputs the loop filter information 16 to the loop filter processing unit 106, the conversion processing setting unit 109, and the entropy encoder 111, respectively. The encoding control unit 114 outputs the quantization information 18 to the transform / quantization unit 102, the inverse quantization / inverse transform unit 103, the parameter derivation unit 110, and the entropy encoder 111, respectively. The encoding control unit 114 outputs the offset information 19 to the parameter derivation unit 110 and the entropy encoder 111, respectively.

The entropy encoder 111 receives the quantized transform coefficient 13 from the transform / quantization unit 102, and inputs the loop filter information 16, quantization information 18, and offset information 19 from the encoding control unit 114. The entropy encoder 111 performs entropy encoding (that is, variable length encoding) on the quantized transform coefficient 13, the loop filter information 16, the quantization information 18, and the offset information 19 to obtain encoded data 25. The entropy encoder 111 outputs the encoded data 25 to the multiplexer 112.

Note that the entropy encoder 111 may encode information other than the above. For example, the entropy encoder 111 may input conversion processing information 17 (to be described later) from the conversion processing setting unit 109 and perform entropy encoding as an element of the encoded data 25. The conversion processing information 17 is encoded, for example, in block units, slice units, or sequence units. However, since the conversion processing information 17 can be uniquely derived based on the loop filter information 16, it does not necessarily have to be given to the decoding side.

The multiplexer 112 receives the encoded data 25 from the entropy encoder 111. The multiplexer 112 multiplexes the encoded data 25 according to a predetermined multiplexing method to obtain the bit stream 26. The multiplexer 112 outputs the bit stream 26 to the outside (for example, a transmission system or a storage system (not shown)).

The conversion processing setting unit 109 inputs the loop filter information 16 from the encoding control unit 114. Based on the loop filter information 16, the conversion process setting unit 109 sets a conversion process applied in the parameter derivation unit 110 described later. Specifically, the parameter deriving unit 110 can use a plurality of conversion processes, and the conversion process setting unit 109 sets one of the plurality of conversion processes. The conversion process is set, for example, in block units, slice units, or sequence units. The conversion processing unit 109 generates conversion processing information 17 indicating the set conversion processing and outputs it to the parameter deriving unit 110.

The parameter deriving unit 110 inputs the conversion processing information 17 from the conversion processing setting unit 109, and inputs the quantization information 18 and the offset information 19 from the encoding control unit 114. The parameter deriving unit 110 performs the conversion process specified by the conversion process information 17 based on the quantization information 18 and the offset information 19 to obtain the filter control parameter 20. The filter control parameter 20 controls the deblocking filter process performed by the deblocking filter processing unit 105. The parameter deriving unit 110 may exclude the offset information 19 from the application target of the conversion process. The parameter deriving unit 110 outputs the filter control parameter 20 to the deblocking filter processing unit 105.

For example, the filter control parameter 20 can include a parameter related to a determination condition for application / non-application of the deblocking filter process. In addition, the filter control parameter 20 can include a parameter related to the type of deblocking filter processing to be applied or the determination condition of the strength.

Specifically, the parameter deriving unit 110 includes a switching unit 131 and a conversion processing unit 132, as shown in FIG. The conversion processing unit 132 includes at least a first conversion processing unit 132-1 for applying the first conversion processing and a second conversion processing unit 132-2 for applying the second conversion processing. Of course, the conversion processing unit 132 may be able to use three or more conversion processes.

The switching unit 131 sets the output destination of the quantization information 18 and the offset information 19 according to the conversion processing information 17 to the first conversion processing unit 132-1, the second conversion processing unit 132-2, or another conversion processing unit. Switch between. For example, if the loop filter information 16 indicates that the loop filter processing is not applied, conversion processing information 17 designating the first conversion processing is given to the switching unit 131. On the other hand, if the loop filter information 16 indicates application of the loop filter processing, conversion processing information 17 designating the second conversion processing is given to the switching unit 131. Furthermore, when the loop filter information 16 includes a filter coefficient for loop filter processing, the conversion processing may be further subdivided according to the type or strength of the loop filter processing.

The first conversion processing unit 132-1 and the second conversion processing unit 132-2 realize the first conversion processing and the second conversion processing, respectively, by using, for example, a conversion table or a conversion formula. In general, the conversion table is useful for speeding up the processing, and the conversion formula is useful for saving memory capacity. The conversion process may be realized by a method other than the conversion table or the conversion formula.

For example, the first conversion processing unit 132-1 implements the first conversion processing using the conversion table A, and the second conversion processing unit 132-2 implements the second conversion processing using the conversion table B. To do. FIG. 5 illustrates the conversion table A and the conversion table B. The conversion table A and the conversion table B in FIG. 5 convert the combined value QPindex based on the quantization information 18 and the offset information 19 into β, which is an element of the filter control parameter 20, as shown in FIG. QPindex is obtained, for example, by the following mathematical formula (1). The QPindex may be obtained by a weighted sum of the quantization information 18 and the offset information 19.

As is apparent from FIGS. 5 and 6, β obtained by the second conversion process is smaller than β obtained by the first conversion process. As will be described later, β is a parameter (threshold value) related to a determination condition for application / non-application of the deblocking filter process, and the application rate of the deblocking filter process can be reduced by using a smaller β. As a result, when the loop filter process is applied, it becomes difficult to apply the deblocking filter process. Further, in the conversion table A, β changes abruptly at QPindex = 15, 16, and deblocking filter processing is not applied until QPindex = 15. On the other hand, by gradually changing β as in the conversion table B, it is difficult to gradually apply the deblocking filter process.

For example, the first conversion processing unit 132-1 implements the first conversion process using the conversion formula shown in the following formula (2), and the second conversion processing unit 132-2 sets the following formula (3). The second conversion process may be realized using the conversion formula shown in FIG. In Equation (3), γ <1 and φ <1. Note that values such as the slope γ or φ and the intercept may be encoded as part of the conversion processing information 17. In this case, the values of the gradient γ or φ, the intercept, and the like are also encoded, for example, in block units, slice units, or sequence units, as in the conversion processing information 17.

In the above description, the parameter β related to the determination condition for application / non-application of the deblocking filter process is exemplified, but the filter control parameter 20 is not limited thereto. For example, the filter control parameter 20 may include various parameters related to the deblocking filter process, such as a parameter related to the determination condition of the strength or type of the deblocking filter process. Here, the filter control parameter 20 will be specifically described.
Application / non-application of the deblocking filter process may be determined for each line across the block boundary, or may be determined for the entire block boundary. When determining the application / non-application of the deblocking filter process for each line, the pixel group illustrated in FIG. 12 is considered. Specifically, the deblocking filter processing unit 105 determines the application of the deblocking filter process if the following conditional expression (4) is true, and otherwise determines the non-application of the deblocking filter process.

In the conditional expression (4), α is an element of the filter control parameter 20 as in β. The deblocking filter processing unit 105 can further determine the strength or type when determining the application of the deblocking filter processing. For example, if the target pixel p or the adjacent pixel q belongs to an intra block and includes a block boundary between p and q, the deblocking filter processing unit 105 performs a strong low-pass filter (so-called strong filter). ) Is applied. Otherwise, the deblocking filter processing unit 105 determines to apply a weak low-pass filter (so-called weak filter). When the weak filter is applied, high-frequency components included in the application target are easily maintained.

When determining the application / non-application of the deblocking filter process over the entire block boundary, the pixel group illustrated in FIG. 13 is considered. Specifically, the deblocking filter processing unit 105 determines the application of the deblocking filter process if the following conditional expression (5) is true, and determines the non-application of the deblocking filter process otherwise.

The deblocking filter processing unit 105 can further determine the strength or type when determining the application of the deblocking filter processing. For example, if the following conditional expression (6) is true, the deblocking filter processing unit 105 determines to apply the strong filter. Otherwise, the deblocking filter processing unit 105 determines to apply the weak filter. In the conditional expression (6), t _c is one element of the filter control parameter 20 like β. In the conditional expression (6), i takes an integer of 0 ≦ i ≦ 7.

Hereinafter, a part of the operation of the moving picture encoding apparatus in FIG. 1 (particularly, the operation of the conversion processing setting unit 109, the parameter deriving unit 110, and the loop filter processing unit 106) will be described with reference to FIG. Note that the process of FIG. 4 can be implemented with appropriate modifications on the decoding side. Further, the process of FIG. 4 can be expanded when three or more types of conversion processes are available.
When the processing of FIG. 4 starts, the conversion processing setting unit 109 inputs the loop filter information 16 from the encoding control unit 114 (step S201). The conversion process setting unit 109 refers to the loop filter information 16 input in step S201, and determines whether or not the loop filter process has been applied to the target image (step S202). The target image is, for example, a pixel set in block units, slice units, or sequence units. If the loop filter process is applied to the target image, the process proceeds to step S204; otherwise, the process proceeds to step S203.

In step S203, the conversion process setting unit 109 generates conversion process information 17 indicating that the first conversion process has been set. In step S204, the conversion process setting unit 109 generates conversion process information 17 indicating that the second conversion process has been set.

The parameter deriving unit 110 inputs the quantization information 18 and the offset information 19 from the encoding control unit 114, and inputs the conversion processing information 17 generated in step S203 or step S204 from the conversion processing setting unit 109 (step S205). . The parameter deriving unit 110 performs the conversion process specified by the conversion process information 17 input in step S205 based on the quantization information 18 and the offset information 19, and derives the filter control parameter 20 (step S206).

The deblocking filter processing unit 105 receives the filter control parameter 20 derived in step S206, and performs deblocking filter processing on the locally decoded image 15 according to the input (step S207).

Note that the moving picture encoding apparatus of FIG. 1 can be modified as shown in FIG. 2 is different from that in FIG. 1 in the execution order of the deblocking filter process and the loop filter process. Specifically, the encoding unit 123 of the moving image encoding apparatus in FIG. 2 includes a loop filter processing unit 121 and a deblocking filter processing unit 122.

The loop filter processing unit 121 inputs the local decoded image 15 from the adder 104 and inputs the loop filter information 16 from the encoding control unit 124. The loop filter processing unit 121 performs loop filter processing on the local decoded image 15 (block thereof) according to the loop filter information 16 to obtain a filtered image (signal) 27. The loop filter processing unit 121 outputs the filtered image 27 to the deblocking filter processing unit 122.

The deblocking filter processing unit 122 inputs the filter processed image 27 from the loop filter processing unit 121 and inputs the filter control parameter 20 from the parameter derivation unit 110. The deblocking filter processing unit 122 performs deblocking filter processing on the filtered image 27 (its block boundary) according to the filter control parameter 20 to obtain the restored image 22. The deblocking filter processing unit 122 stores the restored image 22 in the frame memory 107.

(Video decoding device)
The moving picture decoding apparatus according to the first embodiment includes a demultiplexer 301, a decoding unit 311 and a decoding control unit 312 as shown in FIG. The decoding unit 311 decodes the encoded data 31 to obtain a restored image (signal) 36 as an output image (signal). The decoding unit 311 includes an entropy decoder 302, an inverse quantization / inverse conversion unit 303, an adder 304, a deblocking filter processing unit 305, a loop filter processing unit 306, a frame memory 307, a prediction unit 308, and a conversion processing setting unit. 309 and a parameter deriving unit 310. The decoding control unit 312 performs overall control of the decoding unit 311.

The demultiplexer 301 inputs the bit stream 26 from the outside (for example, a transmission system or a storage system not shown). The demultiplexer 301 demultiplexes (that is, separates) the bit stream 26 according to a predetermined multiplexing method, and obtains encoded data 31. The demultiplexer 301 outputs the encoded data 31 to the entropy decoder 302.

The entropy decoder 302 receives the encoded data 31 from the demultiplexer 301. The entropy decoder 302 entropy-decodes the encoded data 31 to obtain at least quantized transform coefficients 32, loop filter information 39, quantized information 40, and offset information 41.

The entropy decoder 302 outputs the quantized transform coefficient 32 to the inverse quantization / inverse transform unit 303. The entropy decoder 302 outputs the loop filter information 39 to the loop filter processing unit 306 and the conversion processing setting unit 309, respectively. The entropy decoder 302 outputs the quantization information 40 to the inverse quantization / inverse transform unit 303 and the parameter derivation unit 310, respectively. The entropy decoder 302 outputs the offset information 41 to the parameter derivation unit 310, respectively.

The inverse quantization / inverse transform unit 303 inputs the quantized transform coefficient 32 and the quantization information 40 from the entropy decoder 302. The inverse quantization / inverse transform unit 303 performs a predetermined inverse quantization process and inverse transform process on the quantized transform coefficient 32 to restore the prediction error (signal) 33. The predetermined inverse quantization process and inverse transform process are inverse processes of the transform process and the quantization process on the encoding side. The inverse quantization / inverse transform unit 303 performs an inverse quantization process according to the quantization information 40. Further, the inverse quantization / inverse transform unit 303 may perform an inverse quantization process according to the offset information 41. The inverse quantization / inverse transform unit 303 outputs the prediction error 33 to the adder 304.

The adder 304 receives the prediction error 33 from the inverse quantization / inverse conversion unit 303 and the prediction image (signal) 38 from the prediction unit 308. The adder 304 adds the prediction error 33 and the predicted image 38 to obtain a decoded image (signal) 34. The adder 304 outputs the decoded image 34 to the deblocking filter processing unit 305.

The deblocking filter processing unit 305 is the same as or similar to the deblocking filter processing unit 105 described above. That is, the deblocking filter processing unit 305 inputs the decoded image 34 from the adder 304 and inputs the filter control parameter 43 from the parameter derivation unit 310. Here, the filter control parameter 43 is the same as or similar to the filter control parameter 20 described above. The deblocking filter processing unit 105 performs a deblocking filter process on the decoded image 34 (its block boundary) according to the filter control parameter 43 to obtain a filtered image (signal) 35. The deblocking filter processing unit 305 outputs the filtered image 35 to the loop filter processing unit 306.

The loop filter processing unit 306 inputs the filter processed image 35 from the deblocking filter processing unit 305 and inputs the loop filter information 39 from the entropy decoder 302. The loop filter processing unit 306 performs loop filter processing on the filter processed image 35 (block thereof) according to the loop filter information 39 to obtain a restored image 36. The loop filter processing unit 306 outputs the restored image 36 to the outside (for example, a display device (not shown)) and stores the restored image 36 in the frame memory 307.

The frame memory 307 stores the restored image 36 from the loop filter processing unit 306 as a reference image (signal) 37. The reference image 37 is read by the prediction unit 308 as necessary. In addition to the reference image 37, the frame memory 307 may store information necessary for decoding.

The prediction unit 308 reads the reference image 37 from the frame memory 307. The prediction unit 308 performs a prediction process (for example, an intra prediction process or an inter prediction process) based on the reference image 37, and obtains a predicted image 38. The prediction unit 308 may perform a prediction process according to prediction information (not shown) decoded by the entropy encoder 302. The prediction unit 308 outputs the predicted image 38 to the adder 304.

The conversion process setting unit 309 is the same as or similar to the conversion process setting unit 109 described above. That is, the conversion process setting unit 309 inputs the loop filter information 39 from the entropy decoder 302. The conversion process setting unit 309 sets the conversion process applied in the parameter derivation unit 310 based on the loop filter information 39. Specifically, the parameter deriving unit 310 can use a plurality of conversion processes, and the conversion process setting unit 309 sets one of the plurality of conversion processes. The conversion process is set, for example, in block units, slice units, or sequence units. The conversion processing unit 309 generates conversion processing information 42 indicating the set conversion processing and outputs it to the parameter deriving unit 310. It is assumed that the conversion processing information 42 is encoded on the encoding side and is given to the moving picture decoder in FIG. In such a case, the entropy decoder 302 may decode the transform processing information 42 and output it directly to the parameter derivation unit 310. According to such a configuration, the conversion process setting unit 309 is not necessary.

The parameter deriving unit 310 is the same as or similar to the parameter deriving unit 110 described above. That is, the parameter deriving unit 310 inputs the conversion processing information 42 from the conversion processing setting unit 309 (or the entropy decoder 302), and inputs the quantization information 40 and the offset information 41 from the entropy decoder 302. The parameter deriving unit 310 applies the conversion process specified by the conversion process information 42 to the quantization information 40 and the offset information 41 to obtain the filter control parameter 43. The parameter deriving unit 310 may exclude the offset information 41 from the application target of the conversion process. The parameter deriving unit 310 outputs the filter control parameter 43 to the deblocking filter processing unit 305.

Note that the moving picture decoding apparatus in FIG. 7 can be modified as shown in FIG. The moving picture decoding apparatus in FIG. 8 differs from that in FIG. 7 in the execution order of the deblocking filter process and the loop filter process. Specifically, the decoding unit 323 of the video decoding device in FIG. 8 includes a loop filter processing unit 321 and a deblocking filter processing unit 322. The decryption control unit 324 performs overall control of the decryption unit 323.

The loop filter processing unit 321 inputs the decoded image 34 from the adder 304 and inputs the loop filter information 39 from the entropy decoder 302. The loop filter processing unit 321 performs loop filter processing on the decoded image 34 (block thereof) according to the loop filter information 39 to obtain a filtered image (signal) 44. The loop filter processing unit 321 outputs the filtered image 44 to the deblocking filter processing unit 322.

The deblocking filter processing unit 322 inputs the filter processing image 44 from the loop filter processing unit 321 and inputs the filter control parameter 43 from the parameter derivation unit 110. The deblocking filter processing unit 322 performs a deblocking filter process on the filter processed image 44 (its block boundary) according to the filter control parameter 43 to obtain a restored image 36 as an output image. The deblocking filter processing unit 322 outputs the restored image 36 to the outside (for example, a display device (not shown)) and stores the restored image 36 in the frame memory 307.

As described above, the video encoding / decoding device according to the first embodiment switches the conversion process for deriving the control parameter for the deblocking filter process according to the loop filter information. Therefore, according to the moving image encoding / decoding device according to the present embodiment, it is possible to effectively control the deblocking filter process. For example, excessive loop processing on the decoded image is suppressed by making the deblocking filter processing relatively difficult to apply when applying the loop filter processing or by making the filter strength relatively weak. .

(Second Embodiment)
(Moving picture encoding device)
As shown in FIG. 9, the moving image encoding apparatus according to the second embodiment includes an encoding unit 143, an encoding control unit 144, and a multiplexer 112. The encoding unit 143 encodes the input image 11 and obtains encoded data 25. The encoding unit 143 includes a subtracter 101, a transform / quantization unit 102, an inverse quantization / inverse transform unit 103, an adder 104, a deblocking filter processing unit 105, a loop filter processing unit 106, a frame memory 141, and a prediction unit 108. A conversion processing setting unit 142, a parameter deriving unit 110, and an entropy encoding unit 111.

The frame memory 141 stores the loop filter information 16 in addition to the reference image 23. The reference image loop filter information 28 is read by the conversion processing setting unit 142 as necessary.

The conversion processing setting unit 142 reads the loop filter information 28 from the frame memory 141. The conversion process setting unit 142 sets the conversion process applied in the parameter derivation unit 110 based on the loop filter information 28. Specifically, the conversion process setting unit 142 sets one of a plurality of conversion processes that can be used by the parameter derivation unit 110, similarly to the conversion process setting unit 109. The conversion process is set, for example, in block units, slice units, or sequence units. The conversion processing unit 142 generates conversion processing information 29 indicating the set conversion processing and outputs it to the parameter deriving unit 110.

Incidentally, as described above, the conversion processing setting unit 142 generates the conversion processing information 29 using the loop filter information 28 of the reference image instead of the loop filter information 16 of the target image. Therefore, the loop filter information 28 has a delay of, for example, one frame compared to the target image. That is, when the target image belongs to the first frame, the conversion processing setting unit 142 cannot obtain the loop filter information 28. Therefore, when the target image belongs to the first frame, the conversion process setting unit 142 generates the conversion process information 29 according to the initial setting. The initial setting is determined by the encoding control unit 144, for example.

Hereinafter, a part of the operation of the moving picture coding apparatus in FIG. 9 (particularly, the operation of the conversion processing setting unit 142, the parameter deriving unit 110, and the loop filter processing unit 106) will be described with reference to FIG. Note that the processing of FIG. 10 can be implemented with appropriate modifications on the decoding side. Further, the process of FIG. 10 can be expanded when three or more types of conversion processes are available.
When the process of FIG. 10 starts, the conversion process setting unit 142 determines whether the target image belongs to the first frame (that is, FrameNum = 0) (step S211). If the target image belongs to the first frame, the process proceeds to step S212; otherwise, the process proceeds to step S213.

In step S212, the conversion process setting unit 142 receives an initial setting from the encoding control unit 144, and determines which conversion process the initial setting specifies. If the initial setting specifies the second conversion process, the process proceeds to step S204. If the initial setting specifies the first conversion process, the process proceeds to step S203.

In step S213, the conversion processing setting unit 142 reads the loop filter information 28 of the reference image from the frame memory 141. The conversion processing unit 142 refers to the loop filter information 28 read in step S213, and determines whether or not the loop filter processing is applied to the reference image (step S214). It is assumed that the reference image and the target image correspond spatially although the frames are different. That is, the reference image is, for example, a pixel set in block units, slice units, or sequence units. If the loop filter process is applied to the reference image, the process proceeds to step S204; otherwise, the process proceeds to step S203.

In step S203, the conversion process setting unit 142 generates conversion process information 29 indicating that the first conversion process has been set. In step S204, the conversion process setting unit 142 generates conversion process information 29 indicating that the second conversion process has been set.

The parameter deriving unit 110 inputs the quantization information 18 and the offset information 19 from the encoding control unit 144, and inputs the conversion processing information 29 generated in step S203 or step S204 from the conversion processing setting unit 142 (step S205). . The parameter deriving unit 110 applies the transformation process specified by the transformation process information 29 input in step S205 to the quantization information 18 and the offset information 19 to derive the filter control parameter 20 (step S206).

(Video decoding device)
As shown in FIG. 11, the moving picture decoding apparatus according to the second embodiment includes a demultiplexer 301, a decoding unit 333, and a decoding control unit 334. The decoding unit 333 decodes the encoded data 31 and obtains a restored image 36 as an output image. The decoding unit 333 includes an entropy decoder 302, an inverse quantization / inverse conversion unit 303, an adder 304, a deblocking filter processing unit 305, a loop filter processing unit 306, a frame memory 331, a prediction unit 308, and a conversion processing setting unit. 332 and a parameter deriving unit 310. The decryption control unit 334 performs overall control of the decryption unit 333.

The frame memory 331 stores the loop filter information 45 in addition to the reference image 36. The reference image loop filter information 45 is read by the conversion processing setting unit 332 as necessary.

The conversion processing setting unit 332 reads the loop filter information 45 from the frame memory 331. The conversion process setting unit 332 sets the conversion process applied in the parameter derivation unit 310 based on the loop filter information 45. Specifically, the conversion process setting unit 332 sets one of a plurality of conversion processes that can be used by the parameter deriving unit 310, similarly to the conversion process setting unit 309. The conversion process is set, for example, in block units, slice units, or sequence units. The conversion processing unit 332 generates conversion processing information 46 indicating the set conversion processing and outputs it to the parameter deriving unit 310.

Incidentally, as described above, the conversion processing setting unit 332 generates the conversion processing information 46 using the loop filter information 45 of the reference image instead of the loop filter information 39 of the target image. Therefore, the loop filter information 45 has a delay of, for example, one frame compared to the target image. That is, when the target image belongs to the first frame, the conversion processing setting unit 332 cannot obtain the loop filter information 45. Therefore, when the target image belongs to the first frame, the conversion processing setting unit 332 generates conversion processing information 46 according to the initial setting. The initial setting may be determined by the decoding control unit 334, for example, or may be given from the encoding side and decoded by the entropy decoder 302. In addition, it is assumed that the conversion processing information 46 is encoded on the encoding side and given to the moving picture decoder in FIG. In such a case, the entropy decoder 302 may decode the transform processing information 46 and output it directly to the parameter derivation unit 310. According to such a configuration, the conversion process setting unit 332 is not necessary.

As described above, the video encoding / decoding device according to the second embodiment switches the conversion process for deriving the control parameter for the deblocking filter process according to the loop filter information of the reference image. Yes. Therefore, according to the moving image encoding / decoding device according to the present embodiment, it is possible to effectively control the deblocking filter process. For example, excessive loop processing on the decoded image is suppressed by making the deblocking filter processing relatively difficult to apply when applying the loop filter processing or by making the filter strength relatively weak. .

The processing of each of the above embodiments can be realized by using a general-purpose computer as basic hardware. The program for realizing the processing of each of the above embodiments may be provided by being stored in a computer-readable storage medium. The program is stored in the storage medium as an installable file or an executable file. The storage medium can be a computer-readable storage medium such as a magnetic disk, optical disk (CD-ROM, CD-R, DVD, etc.), magneto-optical disk (MO, etc.), semiconductor memory, etc. Any form may be used. Further, the program for realizing the processing of each of the above embodiments may be stored on a computer (server) connected to a network such as the Internet and downloaded to the computer (client) via the network.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ...

Input image

12, 14, 33 ...

Prediction error

13, 32 ... Quantization transform coefficient 15 ... Local decoded

image

16, 28, 39, 45 ...

Loop filter information

17, 29, 42, 46 ...

Conversion processing information

18, 40 ...

Quantization information

19, 41 ... Offset

information

20, 43 ...

Filter control parameters

21, 27, 35, 44 ... Filter processing image 22, 36: restored

image

23, 37 ...

reference image

24, 38 ... predicted

image

25, 31 ... encoded data 26 ... bit stream 34 ... decoded image 101 ... subtractor 102 ... Transformation / quantization unit 103,303 ... Inverse quantization / inverse transformation unit 104,304 ... Addition unit 105,122,305,322 ... Deblocking

filter processing unit

106,12 , 306, 321 ... Loop

filter processing unit

107, 141, 307, 331 ...

Frame memory

108, 308 ...

Prediction unit

109, 142, 309, 332 ... Conversion

processing setting unit

110, 310 ... Parameter deriving unit 111 ... Entropy encoder 112 ... Multiplexer 113, 123, 143 ...

Encoding unit

114, 124, 144 ... Encoding control unit 131 ... Switching unit 132- ..Conversion processing unit 301: Demultiplexer 302 ... Entropy decoder 311,323,333 ... Decoding unit 312,324,334 ... Decoding control unit

Claims

Performing loop filter processing according to the loop filter information;
Setting one of a plurality of conversion processes according to the loop filter information, and generating conversion process information indicating the set conversion process;
Performing transformation processing specified by the transformation processing information based on quantization information, and deriving filter control parameters;
Performing deblocking filtering according to the filter control parameters;
A video encoding method comprising: encoding at least the loop filter information and the quantization information.
The loop filter information includes information indicating application / non-application of the loop filter processing,
If the loop filter process is not applied, the first conversion process is set, and if the loop filter process is applied, the second conversion process is set.
The moving image encoding method according to claim 1.
The filter control parameter obtained by the second conversion process is compared with the filter control parameter obtained by the first conversion process (1) a first difference that makes the deblocking filter process difficult to apply, and (2) The moving picture encoding method according to claim 2, wherein at least one of the second differences in which the filter strength of the applied deblocking filter process is likely to be weakened is provided.
The moving picture encoding method according to claim 1, wherein the filter control parameter is derived by applying a conversion process specified by the conversion process information to a synthesized value of the quantization information and the offset information.
The moving picture encoding method according to claim 1, wherein at least one of the plurality of conversion processes is realized using a conversion table.
The moving image encoding method according to claim 1, wherein at least one of the plurality of conversion processes is realized using a conversion formula.
Decoding at least loop filter information and quantization information; performing loop filter processing according to the loop filter information;
Setting one of a plurality of conversion processes according to the loop filter information, and generating conversion process information indicating the set conversion process;
Performing transformation processing specified by the transformation processing information based on the quantization information, and deriving filter control parameters;
And performing a deblocking filtering process according to the filter control parameter.
The loop filter information includes information indicating application / non-application of the loop filter processing,
If the loop filter process is not applied, the first conversion process is set, and if the loop filter process is applied, the second conversion process is set.
The moving picture decoding method according to claim 7.
The filter control parameter obtained by the second conversion process is compared with the filter control parameter obtained by the first conversion process (1) a first difference that makes the deblocking filter process difficult to apply, and (2) The moving picture decoding method according to claim 8, wherein the moving picture decoding method has at least one of the second differences in which the filter strength of the applied deblocking filter processing tends to be weak.
The moving picture decoding method according to claim 7, wherein the filter control parameter is derived by applying a transformation process specified by the transformation process information to a synthesized value of the quantization information and the offset information.
The moving picture decoding method according to claim 7, wherein at least one of the plurality of conversion processes is realized using a conversion table.
The moving picture decoding method according to claim 7, wherein at least one of the plurality of conversion processes is realized using a conversion formula.
A loop filter processing unit that performs loop filter processing according to the loop filter information;
A generation unit configured to set one of a plurality of conversion processes according to the loop filter information and generate conversion process information indicating the set conversion process;
A derivation unit that performs a transformation process specified by the transformation process information based on quantization information and derives a filter control parameter;
In accordance with the filter control parameter, a deblocking filter processing unit that performs a deblocking filter process,
A video encoding device comprising: an encoding unit that encodes at least the loop filter information and the quantization information.
A decoding unit that decodes at least loop filter information and quantization information; a loop filter processing unit that performs loop filter processing according to the loop filter information;
A generation unit configured to set one of a plurality of conversion processes according to the loop filter information and generate conversion process information indicating the set conversion process;
A derivation unit that performs a transformation process specified by the transformation process information based on the quantization information and derives a filter control parameter;
A moving picture decoding apparatus comprising: a deblocking filter processing unit that performs a deblocking filter process according to the filter control parameter.