WO2012077347A1 - Decoding method - Google Patents

Abstract

A decoding method comprises: an entropy decoding step of performing entropy decoding for an encoded signal and generating quantized coefficients and a prediction mode; a transform control step of outputting transform control information on the basis of the prediction mode; an inverse quantization step of inverse-quantizing the quantized coefficients and generating a decoded transform output signal; and an inverse orthogonal transform step of sequentially performing the horizontal transform and vertical transform in a separable inverse orthogonal transform for the decoded transform output signal. In the inverse orthogonal transform step, in each of the horizontal transform and vertical transform, an inverse orthogonal transform is performed for the N-point (N is a natural number) decoded transform output signal by an N-point inverse discrete cosine transform when the transform control information indicates a first mode, and the inverse orthogonal transform is performed for the N-point decoded transform output signal by a 2N-point inverse discrete sine transform when the transform control information indicates a second mode.

Description

Decryption method

The present invention relates to audio encoding and decoding, still image encoding and decoding, and moving image encoding and decoding, and in particular, a method related to a process of converting a space-time domain signal vector to a frequency domain, and The present invention relates to a program for causing a computer to execute the method.

In order to compress audio data and moving image data, a plurality of audio encoding standards and moving image encoding standards have been developed. As an example of the video coding standard, H.264 ITU-T standard called 26x and ISO / IEC standard called MPEG-x. The latest video coding standard is H.264. H.264 / MPEG-4AVC.

FIG. 36A is a diagram showing a configuration for encoding these audio data and moving image data at a low bit rate. The conversion unit 912 converts an input signal, which is various data, or a converted input signal obtained by performing some processing on the input signal from the space-time domain to the frequency domain, and outputs a converted output signal with reduced correlation. In addition, in order to distinguish conversion from reverse conversion, it may be called forward conversion.

The quantization unit 913 quantizes the conversion output signal output from the conversion unit 912, and outputs a quantization coefficient with a small total data amount. The entropy encoding unit 919 encodes the quantization coefficient output from the quantization unit 913 using an entropy encoding algorithm, and outputs an encoded signal obtained by compressing the remaining data.

The conversion process in the conversion unit 912 will be described in detail. In Expression 1, an N-point vector (N-dimensional signal) input to the conversion unit 912 is a conversion input vector x ⁿ , and an output of a certain conversion T is a conversion output vector y ⁿ . Is a relational expression.

When the transformation T is a linear transformation, the transformation T can be expressed by a matrix product of a transformation coefficient A of an N × N matrix and a transformation input vector x ⁿ as shown in Equation 2.

The conversion unit 912 sequentially performs horizontal conversion in units of rows and vertical conversion in units of columns. The order of horizontal conversion and vertical conversion may be reversed. The conversion unit 912 operates by switching a plurality of types of conversion.

H. When the prediction error signal of the H.264 in-plane prediction is a transform input signal, the transform unit 912 uses a typical discrete cosine transform (DCT) and a transform (second type transform) different from the DCT. H. The H.264 prediction is performed by extrapolating (stretching) the decoded adjacent pixels in a specific direction indicated by the prediction mode.

The conversion unit 912 uses the above-described second type conversion for horizontal conversion or vertical conversion for an angle parallel to the prediction direction, and uses the above-described typical for horizontal conversion or vertical conversion for an angle perpendicular to the prediction direction. A discrete cosine transform (DCT) is used. As a result, it is known that compression performance is improved as compared with using only DCT (refer to Non-Patent Document 1 for details).

In FIG. 36A, based on the prediction mode which is information indicating the prediction direction of the in-plane prediction, the conversion control unit 930 instructs the type of conversion (DCT or second type conversion) used in the conversion unit 912. Outputs conversion control information. The conversion unit 912 performs horizontal conversion and vertical conversion according to the conversion control information.

FIG. 36B is a block diagram showing a decoding device. The entropy decoding unit 924 entropy-decodes the encoded signal to generate a quantization coefficient and a prediction mode. The inverse quantization unit 914 inversely quantizes the quantization coefficient and outputs a decoded conversion output signal (the decoded conversion output signal may be referred to as an inverse conversion input signal). Based on the prediction mode signal, conversion control unit 930 outputs conversion control information for instructing the type of conversion in horizontal conversion and vertical conversion (inverse conversion in the decoding apparatus).

The inverse conversion unit 915 inversely converts the decoded conversion output signal using the conversion type indicated by the conversion control information, and outputs a decoded conversion input signal (sometimes referred to as an inverse conversion output signal).

Expression 4 is an expression indicating coefficients K _{i, j} (i, j = 0... N−1) of a forward conversion matrix for N-point input signals. Expression 5 is an expression indicating the coefficient K ′ _{i, j} (i, j = 0... N−1) of the inverse transformation matrix.

The inverse transformation matrix has a transposed matrix relationship with the forward transformation matrix. FIG. 37A shows an example in which a transformation matrix for forward transformation when N = 4 points is expressed in 8 bits. FIG. 37B shows an example of a transformation matrix for inverse transformation.

In typical DCT, there is a high-speed calculation algorithm using butterfly calculation or the like. For this reason, the amount of calculation (particularly the number of multiplications) is reduced. However, in the second type of conversion as shown in FIGS. 37A and 37B, there is no efficient high-speed algorithm. Therefore, the number of multiplications increases. In particular, the problem becomes more prominent as the conversion size becomes larger, such as N = 16 or N = 32.

That is, multiplication is necessary for conversion to the frequency domain optimized based on statistical properties in the conventional image encoding device and the conventional image decoding device. And the amount of calculation for the multiplication is large. More specifically, the amount of calculation is large in the second type of conversion different from typical DCT.

In order to solve the above problems, a decoding method according to the present invention is a decoding method for decoding an encoded signal, and performs entropy decoding on the encoded signal to generate a quantized coefficient and a prediction mode. Information for controlling each of horizontal transformation and vertical transformation in the separation-type inverse orthogonal transformation based on the entropy decoding step and the prediction mode, and transformation that is information indicating the first mode or the second mode A transform control step for outputting control information; an inverse quantization step for inversely quantizing the quantization coefficient to generate a decoded transform output signal; and the demultiplexed inverse orthogonal transform for the decoded transform output signal. An inverse orthogonal transform step for sequentially performing horizontal transform and vertical transform, wherein the inverse orthogonal transform step includes that of the horizontal transform and the vertical transform. In this case, when the transform control information indicates the first mode, the inverse orthogonal transform is performed on the decoded transform output signal of N (N is a natural number) by N-point discrete cosine inverse transform, When the transform control information indicates the second mode, the inverse orthogonal transform is performed on the N-point decoded transform output signal by 2N-point discrete sine transform.

This makes it possible to reduce the amount of calculation for conversion and inverse conversion.

Further, the inverse orthogonal transform used in the second mode includes a butterfly computation step for performing a butterfly computation on an input signal, and N / 2 points of the addition result among the outputs of the butterfly computation. An addition result conversion step for executing discrete cosine transform Type-4, and a subtraction result conversion step for recursively executing the inverse orthogonal transform used in the second mode on the subtraction result of the output of the butterfly operation And a post-conversion step that performs rearrangement and sign change on the output of the addition result conversion step and the output of the subtraction result conversion step, and outputs an N-point inverse conversion output signal. But you can.

The decoding method according to the present invention is a decoding method for decoding an encoded signal, wherein entropy decoding is performed on the encoded signal to generate a quantized coefficient and a prediction mode, and the prediction mode Is a conversion control step for outputting conversion control information that is information for controlling each of horizontal conversion and vertical conversion in separation-type inverse orthogonal conversion, and is information indicating the first mode or the second mode. And an inverse quantization step for inversely quantizing the quantization coefficient to generate a decoded transform output signal, and a horizontal transform and a vertical transform in the separation-type inverse orthogonal transform are sequentially performed on the decoded transform output signal. In the inverse orthogonal transform step, the transform control is performed in each of the horizontal transform and the vertical transform. When the report indicates the first mode, the inverse orthogonal transform is performed on the decoded transform output signal of N (N is a natural number) points by N-point discrete cosine inverse transform, and the transform control information is When the second mode is indicated, a decoding method may be used in which the inverse orthogonal transform is performed by N-point discrete sine transform on the N-point decoded transform output signal.

The discrete sine transform used in the inverse orthogonal transform may be DST-Type2.

The discrete sine transform used in the inverse orthogonal transform may be DST-Type4.

The number of multiplications of the second type conversion and inverse conversion can be reduced by the encoding method or decoding method according to the present invention.

1A is a block diagram of an encoding apparatus according to Embodiment 1. FIG. FIG. 1B is a block diagram of the decoding apparatus according to Embodiment 1. FIG. 2A is a diagram showing an example (N = 4) of a forward transformation matrix according to Embodiment 1. FIG. 2B is a diagram illustrating an example (N = 4) of the inverse transformation matrix according to Embodiment 1. FIG. 2C is a diagram illustrating an example of a transformation matrix for forward transformation according to Embodiment 1 (N = 4, 2 / N square root excluded version). FIG. 2D is a diagram showing an example of the inverse transformation matrix (N = 4, 2 / N square root excluded version) according to Embodiment 1. FIG. 3A is a diagram showing an example (N = 8) of a forward transformation matrix according to Embodiment 1. FIG. 3B is a diagram illustrating an example (N = 8) of the inverse transformation matrix according to Embodiment 1. FIG. 3C is a diagram showing an example of a forward transformation matrix (N = 8, 2 / N square root excluded version) according to Embodiment 1. FIG. 3D is a diagram showing an example of an inverse transformation matrix (N = 8, 2 / N square root excluded version) according to Embodiment 1. FIG. 4 is a diagram showing an example (N = 16) of the inverse transformation matrix according to the first embodiment. FIG. 5 is a diagram illustrating an example of the inverse transformation matrix (N = 16, 2 / N square root excluded version) according to the first embodiment. FIG. 6 is a diagram showing a list of types I to IV of discrete sine transform and discrete cosine transform. FIG. 7 is a block diagram illustrating a conversion unit according to the second embodiment. FIG. 8 is a block diagram illustrating an inverse conversion unit according to the second embodiment. FIG. 9A is a signal flow diagram of the conversion unit (N = 4) according to Embodiment 3. FIG. 9B is a diagram illustrating pseudo code of the conversion unit (N = 4) according to Embodiment 3. FIG. 10A is a signal flow diagram of the inverse transform unit (N = 4) according to Embodiment 3. FIG. 10B is a diagram illustrating pseudo code of the inverse transform unit (N = 4) according to Embodiment 3. FIG. 11 is a signal flow diagram of the inverse transform unit (N = 8) according to Embodiment 3. FIG. 12 is a flowchart of the inverse conversion process according to the third embodiment. FIG. 13 is a signal flow schematic diagram of the inverse transform unit (N = 16) according to Embodiment 3. FIG. 14 is a signal flow schematic diagram when a typical DCT and a second type of conversion are shared in the inverse conversion unit according to the third embodiment. FIG. 15A is a diagram illustrating an example (N = 4, 8-bit notation) of a forward transformation matrix and an inverse transformation matrix according to Embodiment 4. FIG. 15B is a diagram showing an example of a transformation matrix for forward transformation and inverse transformation according to Embodiment 4 (N = 4, 2 / N square root excluded version, 8-bit notation). FIG. 15C is a diagram illustrating an example (N = 8, 8-bit notation) of forward and inverse transformation matrices according to Embodiment 4. FIG. 15D is a diagram showing an example of a transformation matrix of forward transformation and inverse transformation according to Embodiment 4 (N = 8, 2 / N square root excluded version, 8-bit notation). FIG. 16A is a diagram showing an example (N = 4, 7-bit notation) of a transformation matrix for forward transformation and inverse transformation according to Embodiment 4. FIG. 16B is a diagram showing an example of a transformation matrix for forward transformation and inverse transformation according to Embodiment 4 (N = 4, 2 / N square root excluded version, 7-bit notation). FIG. 16C is a diagram illustrating an example (N = 8, 7-bit notation) of a forward transformation matrix and an inverse transformation matrix according to Embodiment 4. FIG. 16D is a diagram showing an example of a transformation matrix for forward transformation and inverse transformation according to Embodiment 4 (N = 8, 2 / N square root excluded version, 7-bit notation). FIG. 17 is an overall configuration diagram of a content supply system that implements a content distribution service. FIG. 18 is an overall configuration diagram of a digital broadcasting system. FIG. 19 is a block diagram illustrating a configuration example of a television. FIG. 20 is a block diagram illustrating a configuration example of an information reproducing / recording unit that reads and writes information from and on a recording medium that is an optical disk. FIG. 21 is a diagram illustrating a structure example of a recording medium that is an optical disk. FIG. 22A illustrates an example of a mobile phone. FIG. 22B is a block diagram illustrating a configuration example of a mobile phone. FIG. 23 is a diagram showing a structure of multiplexed data. FIG. 24 is a diagram schematically showing how each stream is multiplexed in the multiplexed data. FIG. 25 is a diagram showing in more detail how the video stream is stored in the PES packet sequence. FIG. 26 is a diagram illustrating the structure of TS packets and source packets in multiplexed data. FIG. 27 is a diagram illustrating a data structure of the PMT. FIG. 28 is a diagram illustrating an internal configuration of multiplexed data information. FIG. 29 shows the internal structure of stream attribute information. FIG. 30 shows steps for identifying video data. FIG. 31 is a block diagram illustrating a configuration example of an integrated circuit that realizes the moving picture coding method and the moving picture decoding method according to each embodiment. FIG. 32 is a diagram showing a configuration for switching the drive frequency. FIG. 33 is a diagram showing steps for identifying video data and switching between driving frequencies. FIG. 34 is a diagram showing an example of a look-up table in which video data standards are associated with drive frequencies. FIG. 35A is a diagram illustrating an example of a configuration for sharing a module of a signal processing unit. FIG. 35B is a diagram illustrating another example of a configuration for sharing a module of a signal processing unit. FIG. 36A is a block diagram showing an encoding apparatus according to the prior art. FIG. 36B is a block diagram showing a decoding device according to the prior art. FIG. 37A is a diagram illustrating an example (N = 4) of a forward transformation matrix according to the related art. FIG. 37B is a diagram showing an example (N = 4) of the inverse transformation matrix according to the conventional technique.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. The present invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

(Embodiment 1)
FIG. 1A is a configuration diagram of an encoding apparatus according to the present embodiment. The conversion unit 120 converts an input signal, which is various data, or a converted input signal obtained by performing some processing on the input signal from the space-time domain to the frequency domain, and outputs a converted output signal with reduced correlation. In addition, in order to distinguish transformation (orthogonal transformation) from inverse transformation (inverse orthogonal transformation), it may be called forward transformation.

The quantization unit 130 quantizes the conversion output signal output from the conversion unit 120 and outputs a quantization coefficient with a small total data amount. The entropy encoding unit 190 encodes the quantization coefficient output from the quantization unit 130 using an entropy encoding algorithm, and outputs an encoded signal obtained by compressing the remaining data.

In FIG. 1A, based on a prediction mode that is information indicating a prediction direction of in-plane prediction, the conversion control unit 300 instructs a conversion type (DCT or second type conversion) used in the conversion unit 120. Outputs conversion control information. The conversion unit 120 performs horizontal conversion and vertical conversion according to the conversion control information.

FIG. 2B is a configuration diagram of the decoding apparatus according to the present embodiment. The entropy decoding unit 240 entropy decodes the encoded signal to generate a quantized coefficient and a prediction mode. The inverse quantization unit 140 inversely quantizes the quantized coefficient and outputs a decoded transform output signal (the decoded transform output signal may be referred to as an inverse transform input signal). Based on the prediction mode signal, conversion control unit 300 outputs conversion control information for instructing the type of conversion in horizontal conversion and vertical conversion (inverse conversion in the decoding apparatus).

The inverse conversion unit 150 performs inverse conversion on the decoded conversion output signal using the conversion type indicated by the conversion control information, and outputs a decoded conversion input signal (sometimes referred to as an inverse conversion output signal).

Signals such as audio, still images or moving images are input to the encoding device. This encoding target signal (Original Signal) or a prediction error signal that is a difference between this signal and a prediction signal created based on the previously input encoding target signal is used as a conversion input signal. Is input. In general, a prediction error signal is often input as a conversion target. However, when prediction is not performed while avoiding the introduction of errors in the transmission path or when the energy is small, the input signal is input as a conversion target without prediction.

Expression 6 is an expression indicating a conversion matrix of the second type of conversion in the encoding device. Expression 7 is an expression showing a conversion matrix of the second conversion (inverse conversion) in the decoding device. D _i in Equation 6 and Equation 7 is a coefficient and is represented by Equation 8.

FIG. 2A shows the conversion coefficient K _{i, j} of the conversion matrix of the forward conversion in 8 bits when N = 4. FIG. 2B shows the conversion coefficient K ′ _{i, j} of the inverse transformation matrix when N = 4. As in Equation 8, all conversion coefficients include a square root of 2 / N. For this reason, the conversion unit 120 and the inverse conversion unit 150 may perform conversion or inverse conversion on the remainder after separation. FIGS. 2C and 2D show a forward transformation matrix S _{i, j} and an inverse transformation matrix S ′ _{i, j} excluding the 2 / N square root.

The square root of 2 / N separated from the transformation matrix of the forward transformation is superimposed on the quantization step size or norm correction table in the quantization process performed by the quantization unit 130. Thereby, the amount of calculation does not increase by separation. Similarly, the 2 / N square root separated from the inverse transformation matrix is superimposed on the quantization step size or norm correction table in the inverse quantization process performed by the inverse quantization unit 140. As a result, the calculation amount does not increase.

Equation 9 shows a transformation matrix S _{i, j} for forward transformation excluding the square root of 2 / N. Equation 10 shows a transformation matrix S ′ _{i, j} of inverse transformation excluding the square root of 2 / N.

3A to 3D show the transformation matrix at N = 8 by 8 bits. FIG. 3A shows a transformation matrix K _{i, j} for forward transformation. FIG. 3B shows a transformation matrix K ′ _{i, j} for inverse transformation. 3C and 3D show a forward transformation matrix S _{i, j} and an inverse transformation matrix S ′ _{i, j} excluding the square root of 2 / N. FIG. 4 shows a transformation matrix K ′ _{i, j} of inverse transformation at N = 16. FIG. 5 shows an inverse transformation matrix S ′ _{i, j} excluding the square root of 2 / N.

As can be seen from the specific numerical examples of the conversion matrix (FIGS. 2A to 5), many conversion coefficients with the same value are included in the same row or column. Therefore, the arithmetic processing required for these can be made efficient.

Hereinafter, an example of inverse transformation in FIG. 2B will be described. Here, x is a column vector of the converted input signal, X is a column vector of the converted output signal, and Y is a column vector of the inversely converted output signal obtained by inversely converting X. The inverse conversion process is Y = KX, and the calculation process of the second row (i = 1) is expressed by Expression 11.

By developing Equation 11, Y ₁ = K _1,0 X (0) + K _1,1 X (1) + K _1,2 X (2) + K _1,3 X (3) is obtained. The magnitude of the coefficient K _{1, *} is the same as ± 128. Therefore, the number of multiplications is reduced by calculating X _* before each multiplication. That is, the calculation in the second row of the inverse conversion process is executed as Y ₁ = 128 * (X (0) + X (1) −X (2) −X (3)). The transformation matrix according to the present embodiment includes many such equivalent coefficients. Therefore, the number of multiplications can be easily reduced.

(Embodiment 2)
The conversion and inverse conversion according to the present embodiment further reduce the amount of calculation.

FIG. 6 shows four types of discrete cosine transform and discrete sine transform, respectively. When a typical DCT is used for image compression or the like, the forward transformation is DCT type 3 and the inverse transformation is DCT type 2. DCT type 1, DCT type 4, and DST are rarely used for image compression. The forward conversion according to the present embodiment (see Expression 6) corresponds to type 3 among the four types of DST. Equation 6 matches the equation obtained by substituting N = 2N and k = 2j into the DST ^III equation of FIG.

The above equation 12 will be described with reference to the signal flow diagram of FIG. As shown in FIG. 7, a 2N-point signal sequence obtained by alternately adding zero elements to the N-point input signal is input to the 2N-point DST type 3. Of the 2N point DST type 3 output signals, only the first N points are used. The forward conversion according to the present embodiment is equivalent to the conversion as shown in FIG.

Similarly, the inverse transformation (refer to Expression 7) according to the present embodiment corresponds to Type 2 of DST. Equation 7 matches the equation obtained by substituting N = 2N and k = 2j into the DST ^II equation of FIG. In other words, the inverse transformation according to the present embodiment, by inputting a signal sequence of 2N points generated by adding N zero elements behind the input signal N points to DST ^II of 2N points DST ^II Is equivalent to taking out an odd-numbered element from the output signal from.

The above equation 13 will be described with reference to the signal flow diagram of FIG. In the inverse transformation according to the present embodiment, N zero elements are added after the N-point input signal (inverse transformation input signal). The input signal is input to the 2N point DST type 2. Of the DST type 2 output signals, only odd-numbered elements are used.

The chance that the discrete sine transform DST is used for image compression is less than that of the discrete cosine transform. However, Type 2 and Type 3 have an advantage that they are easy to handle because their calculation characteristics are well known. Since the encoding apparatus and decoding apparatus according to the present embodiment are based on DST type 2 and type 3 as described above, they can enjoy the merit of ease of handling.

(Embodiment 3)
This embodiment is an example of a relatively small configuration, and in the conversion and inverse conversion, the processing of the portion where the zero value is input / output in the 2N-point DST is omitted. In the present embodiment, an example is shown in which the transformation matrix C _{i, j} and the inverse transformation matrix C ′ _{i, j} excluding the 2 / N square root are realized. K _{i, j} and K ′ _{i, j} when not removed can be realized by superimposing the multiplications so that the multiplication of the square root of 2 / N occurs only once.

FIG. 9A is a signal flow diagram of forward conversion when N = 4. Data flows along the arrows. When a numerical value is written next to the arrow, the numerical value is multiplied. A circle is a virtual node indicating an intermediate point of data. When a plurality of arrows enter one node, the data of these arrows are added. Conversion input / output data may be out of order. However, the amount of calculation for rearranging them is assumed to be small. Therefore, the rearrangement process may be omitted for convenience of explanation.

In FIG. 9A, the conversion inputs are shown in no particular order. The signal flow diagram of FIG. 9A will be described along FIG. 9B. Of the four converted input signals, the first element x (0) is input to a (0), and the third element x (2) is virtually input to a (1). The No arithmetic processing such as multiplication and addition is performed at the time of these two inputs. For convenience of explanation, input is performed. The fourth element x (3) is multiplied by S (2/8), which is one of Ci _{, j} , and input to a (2). Here, S (n / m) means sin (nπ / m).

In this way, by performing the calculation according to the procedure shown in the signal flow diagram of FIG. 9A, a result equivalent to the result of matrix multiplication of C _{i, j} is obtained. Multiplication and addition processes are efficiently combined, and the number of these operations is reduced.

Similarly, FIG. 10A is a signal flow diagram of C ′ _{i, j} of inverse transformation at N = 4. FIG. 10B is pseudo code. This will be described using these two. A butterfly operation is performed on X which is an inverse conversion input signal. The butterfly operation is an operation that creates a pair of an addition result and a subtraction result with predetermined elements. In the example of FIG. 10A, a (0) = X (0) + X (3), a (1) = X (1) + X (2), a (2) = X (1) −X (2), a The butterfly operation is executed as (3) = X (0) −X (3).

The inverse conversion unit 150 uses a (0) and a (1) which are the results on the addition side among the butterfly calculation results to convert Y (0) which is the first element of the inverse conversion output to s (1 / 8) Derived by * a (0) + s (3/8) * a (1). Further, the inverse transform unit 150 derives Y (2), which is the third element of the inverse transform output signal, from s (3/8) * a (0) −s (3/8) * a (1). .

The inverse transform unit 150 further adds and subtracts a (2) and a (3), which are the results on the subtraction side, among the butterfly calculation results, and multiplies the coefficients. Specifically, the inverse transformation unit 150 derives Y (3), which is the fourth element of the inverse transformation output signal, from s (4/8) * (a (3) −a (2)). Further, the inverse transform unit 150 derives Y (1), which is the second element of the inverse transform output signal, from s (2/8) * (a (3) + a (2)).

Note that s (4/8) is equal to s (1/2), and s (2/8) is equal to s (1/4). The multiplication to obtain Y (3) is only required once for the multiplication of s (4/8). Further, the multiplication for obtaining Y (1) may be performed only once for s (2/8). In the case of the original matrix operation, the number of multiplications is greatly reduced as compared with the case where each is required four times.

It can be seen by comparing FIG. 9A to FIG. 10B that the signal flow diagrams of forward conversion and reverse conversion can be obtained mutually by switching the directions of the arrows. Therefore, only the signal flow diagram of the inverse transformation will be shown in the future.

FIG. 11 is a signal flow diagram of the inverse transformation when N = 8. FIG. 11 shows a plurality of operations (operation 504, operation 604, and operation 704). The operation 504 corresponds to conversion of the subtraction result (subtraction result conversion). The calculation 604 corresponds to conversion of the addition result (addition result conversion). The operation 704 corresponds to the change of the sign (post conversion). Rearrangement may be performed in operation 704. This processing step will be described with reference to the flowchart of FIG.

First, an N-point butterfly operation is performed on the inverse transformation input signal (S101). The N / 2 point on the result side of the butterfly calculation coincides with the DCT type 4 of N / 2 point. Therefore, a known high-speed algorithm for DCT type 4 (see Non-Patent Document 2) is applied. Thereby, the calculation is performed with a low processing amount (S102 and calculation 604). Further, the sign is adjusted (S103 and operation 704).

The N / 2 point on the subtraction result side of the butterfly calculation matches the configuration of the N / 2 point according to the present embodiment. Therefore, by applying the configuration and processing procedure of this embodiment recursively, the calculation of N / 2 points on the subtraction result side is executed (S104). The order of step S102 (calculation 604) and step S103 (calculation 704) may be reversed. These can also be operated in parallel. Note that c (n / m) in FIG. 11 means cos (nπ / m).

The above operations and configurations, ie, operations for DCT type 4 at N = 4, and recursive configurations hold for N power-of-two points. Although the proof is omitted, when the score is M and C ′ _{i, j} of this embodiment is E _M , the calculation according to this embodiment is a small size of M / 2 points as shown in Equation 14. It can be decomposed into a matrix operation.

Here, B _M is a matrix that vertically separates odd and even rows of the matrix. Γ _M is a matrix in which the lower half of the unit matrix has a negative sign. R _M is a matrix corresponding to DCT type 4. I _M is a unit matrix. J _M is a matrix obtained by horizontally inverting the unit matrix. Equation 15 which is a part of the right side of Equation 14 means a typical butterfly operation.

In Equation 14, R _{M / 2} J _{M / 2} means that step S102 is performed on the addition result of the butterfly calculation. Γ _{M / 2} corresponds to step S103. E _{M / 2} corresponds to the recursive step S104.

Equation 14 also holds for larger N. Therefore, an inverse transformation configuration (signal flow and pseudo code) with a low calculation amount can be obtained for N = 16 or N = 32. As shown in the example of N = 4, a forward conversion configuration is obtained from the reverse conversion. FIG. 13 shows a conceptual diagram of N = 16.

As described above, the processing corresponding to the DCT type 4 can be shared with a typical DCT high-speed algorithm. FIG. 14 is a configuration diagram showing sharing of processing. The configuration of the second type of conversion according to the present embodiment is as described above, and is indicated by C ′ _{i, j} in the figure.

On the other hand, in a typical DCT (that is, DCT type III), data is input from the right side in FIG. A process corresponding to Γ for code adjustment is not required. DCT type 4 processing is performed in reverse order. Then, the result is input to the subtraction side of the butterfly calculation unit. Operations are performed on the other data in a typical DCT recursive configuration. Then, the output is input to the addition side of the butterfly calculation unit. The butterfly operation unit performs the process in the reverse order and outputs the result. The output result is equal to the output of a typical DCT.

In the conversion and inverse conversion according to the present embodiment, the amount of calculation is reduced to the same level as a typical DCT. Further, the conversion according to the present embodiment is DST ^III , and the inverse conversion is DST ^II . There are fast algorithms for these. Therefore, the calculation amount is further reduced.

(Embodiment 4)
This embodiment is a derivation from the above-described first to third embodiments. The transformation matrix of the second type of transformation in the encoding apparatus according to the present embodiment is Equation 17. The transformation matrix of the second transformation (inverse transformation) in the decoding device is Equation 18. The inverse transformation K ′ _{i, j} matches the forward transformation K _{i, j} . D _i in Equation 16 and Equation 17 represents a coefficient used for multiplication. This conversion is DST ^IV (DST Type-IV in FIG. 6). DST ^IV also has a high-speed algorithm. For this reason, the amount of calculation is reduced by using this conversion.

FIG. 15A shows the transform coefficient K _{i, j} of the transform matrix of the forward transform at N = 4 and the transform coefficient K ′ _{i, j} of the transform matrix of the inverse transform in 8 bits. FIG. 15B shows conversion coefficients obtained by separating the square root of 2 / N, which is a common coefficient. FIG. 15C shows the conversion coefficient K _{i, j} for forward conversion and the conversion coefficient K ′ _{i, j} for inverse conversion when N = 8. FIG. 15D shows conversion coefficients obtained by separating the square root of 2 / N, which is a common coefficient.

16A to 16D show examples of transform coefficients with 7 bits. FIG. 16A shows the conversion coefficient K _{i, j} for forward conversion and the conversion coefficient K ′ _{i, j} for inverse conversion when N = 4. FIG. 16B shows conversion coefficients obtained by separating the square root of 2 / N, which is a common coefficient. FIG. 16C shows the conversion coefficient K _{i, j} for forward conversion and the conversion coefficient K ′ _{i, j} for inverse conversion when N = 8 points. FIG. 16D shows conversion coefficients obtained by separating the square root of 2 / N, which is a common coefficient.

There is a fast algorithm in DST ^IV . The high-speed DST ^IV algorithm is obtained by shifting the input position by N / 2 points with respect to the N-point input signal sequence based on the high-speed DCT ^IV algorithm. The fast algorithm of DCT ^IV is as described in the first to third embodiments. By using the conversion and inverse conversion described in the present embodiment, the amount of calculation of the second type conversion is reduced.

As mentioned above, although the encoding apparatus and decoding apparatus which concern on this invention were demonstrated based on several embodiment, this invention is not limited to those embodiment. Forms obtained by subjecting those embodiments to modifications conceivable by those skilled in the art, and other forms realized by arbitrarily combining components in those embodiments are also included in the present invention.

For example, another processing unit may execute a process executed by a specific processing unit. In addition, the order in which the processes are executed may be changed, or a plurality of processes may be executed in parallel.

Further, the present invention can be realized not only as an encoding device and a decoding device, but also as a method in which processing means constituting the encoding device and the decoding device are used as steps. For example, these steps are performed by a computer. The present invention can be realized as a program for causing a computer to execute the steps included in these methods. Furthermore, the present invention can be realized as a computer-readable recording medium such as a CD-ROM in which the program is recorded.

The encoding device, decoding device, encoding method, and decoding method according to the present invention can also be applied to, for example, an image encoding device, an image decoding device, an image encoding method, and an image decoding method.

Also, the plurality of components included in the encoding device and the decoding device may be realized as an LSI (Large Scale Integration) that is an integrated circuit. These components may be individually made into one chip, or may be made into one chip so as to include a part or all of them. For example, the components other than the memory may be integrated into one chip. Although referred to here as an LSI, it may be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other technologies derived from it, naturally, using that technology, the components included in the encoding device and decoding device can be integrated into an integrated circuit. You may go.

(Embodiment 5)
By recording a program for realizing the configuration of the moving image encoding method (image encoding method) or the moving image decoding method (image decoding method) shown in each of the above embodiments on a storage medium, each of the above embodiments It is possible to easily execute the processing shown in the form in the independent computer system. The storage medium may be any medium that can record a program, such as a magnetic disk, an optical disk, a magneto-optical disk, an IC card, and a semiconductor memory.

Furthermore, application examples of the moving picture coding method (picture coding method) and the moving picture decoding method (picture decoding method) shown in the above embodiments and a system using the same will be described. The system has an image encoding / decoding device including an image encoding device using an image encoding method and an image decoding device using an image decoding method. Other configurations in the system can be appropriately changed according to circumstances.

FIG. 17 is a diagram showing an overall configuration of a content supply system ex100 that realizes a content distribution service. A communication service providing area is divided into desired sizes, and base stations ex106, ex107, ex108, ex109, and ex110, which are fixed wireless stations, are installed in each cell.

This content supply system ex100 includes a computer ex111, a PDA (Personal Digital Assistant) ex112, a camera ex113, a mobile phone ex114, a game machine ex115 via the Internet ex101, the Internet service provider ex102, the telephone network ex104, and the base stations ex106 to ex110. Etc. are connected.

However, the content supply system ex100 is not limited to the configuration shown in FIG. 17, and may be connected by combining any one of the elements. In addition, each device may be directly connected to the telephone network ex104 without going from the base station ex106, which is a fixed wireless station, to ex110. In addition, the devices may be directly connected to each other via short-range wireless or the like.

The camera ex113 is a device that can shoot moving images such as a digital video camera, and the camera ex116 is a device that can shoot still images and movies such as a digital camera. The mobile phone ex114 is a GSM (registered trademark) (Global System for Mobile Communications) system, a CDMA (Code Division Multiple Access) system, a W-CDMA (Wideband-Code Division Multiple Access) system, or an LTE (Long Term Evolution). It is possible to use any of the above-mentioned systems, HSPA (High Speed Packet Access) mobile phone, PHS (Personal Handyphone System), or the like.

In the content supply system ex100, the camera ex113 and the like are connected to the streaming server ex103 through the base station ex109 and the telephone network ex104, thereby enabling live distribution and the like. In live distribution, the content (for example, music live video) captured by the user using the camera ex113 is encoded as described in the above embodiments (that is, the image encoding of the present invention). Function as a device) and transmit to the streaming server ex103. On the other hand, the streaming server ex103 stream-distributes the content data transmitted to the requested client. Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, and a game machine ex115 that can decode the encoded data. Each device that receives the distributed data decodes the received data and reproduces it (that is, functions as the image decoding device of the present invention).

Note that the captured data may be encoded by the camera ex113, the streaming server ex103 that performs data transmission processing, or may be shared with each other. Similarly, the decryption processing of the distributed data may be performed by the client, the streaming server ex103, or may be performed in common with each other. In addition to the camera ex113, still images and / or moving image data captured by the camera ex116 may be transmitted to the streaming server ex103 via the computer ex111. The encoding process in this case may be performed by any of the camera ex116, the computer ex111, and the streaming server ex103, or may be performed in a shared manner.

Further, these encoding / decoding processes are generally performed in the computer ex111 and the LSI ex500 included in each device. The LSI ex500 may be configured as a single chip or a plurality of chips. It should be noted that moving image encoding / decoding software is incorporated into some recording medium (CD-ROM, flexible disk, hard disk, etc.) that can be read by the computer ex111, etc., and encoding / decoding processing is performed using the software. May be. Furthermore, when the mobile phone ex114 is equipped with a camera, moving image data acquired by the camera may be transmitted. The moving image data at this time is data encoded by the LSI ex500 included in the mobile phone ex114.

Further, the streaming server ex103 may be a plurality of servers or a plurality of computers, and may process, record, and distribute data in a distributed manner.

As described above, in the content supply system ex100, the encoded data can be received and reproduced by the client. Thus, in the content supply system ex100, the information transmitted by the user can be received, decrypted and reproduced by the client in real time, and personal broadcasting can be realized even for a user who does not have special rights or facilities.

In addition to the example of the content supply system ex100, as shown in FIG. 18, the digital broadcast system ex200 also includes at least the video encoding device (video encoding device) or video decoding of each of the above embodiments. Any of the devices (image decoding devices) can be incorporated. Specifically, in the broadcast station ex201, multiplexed data obtained by multiplexing music data and the like on video data is transmitted to a communication or satellite ex202 via radio waves. This video data is data encoded by the moving image encoding method described in the above embodiments (that is, data encoded by the image encoding apparatus of the present invention). Receiving this, the broadcasting satellite ex202 transmits a radio wave for broadcasting, and this radio wave is received by a home antenna ex204 capable of receiving satellite broadcasting. The received multiplexed data is decoded and reproduced by an apparatus such as the television (receiver) ex300 or the set top box (STB) ex217 (that is, functions as the image decoding apparatus of the present invention).

Also, a reader / recorder ex218 that reads and decodes multiplexed data recorded on a recording medium ex215 such as a DVD or a BD, or encodes a video signal on the recording medium ex215 and, in some cases, multiplexes and writes it with a music signal. It is possible to mount the moving picture decoding apparatus or moving picture encoding apparatus described in the above embodiments. In this case, the reproduced video signal is displayed on the monitor ex219, and the video signal can be reproduced in another device or system using the recording medium ex215 on which the multiplexed data is recorded. Alternatively, a moving picture decoding apparatus may be mounted in a set-top box ex217 connected to a cable ex203 for cable television or an antenna ex204 for satellite / terrestrial broadcasting and displayed on the monitor ex219 of the television. At this time, the moving picture decoding apparatus may be incorporated in the television instead of the set top box.

FIG. 19 is a diagram illustrating a television (receiver) ex300 that uses the video decoding method and the video encoding method described in each of the above embodiments. The television ex300 obtains or outputs multiplexed data in which audio data is multiplexed with video data via the antenna ex204 or the cable ex203 that receives the broadcast, and demodulates the received multiplexed data. Alternatively, the modulation / demodulation unit ex302 that modulates multiplexed data to be transmitted to the outside, and the demodulated multiplexed data is separated into video data and audio data, or the video data and audio data encoded by the signal processing unit ex306 Is provided with a multiplexing / demultiplexing unit ex303.

Further, the television ex300 decodes each of the audio data and the video data, or encodes the respective information, the audio signal processing unit ex304, the video signal processing unit ex305 (function as the image encoding device or the image decoding device of the present invention). ), A speaker ex307 for outputting the decoded audio signal, and an output unit ex309 having a display unit ex308 such as a display for displaying the decoded video signal. Furthermore, the television ex300 includes an interface unit ex317 including an operation input unit ex312 that receives an input of a user operation. Furthermore, the television ex300 includes a control unit ex310 that performs overall control of each unit, and a power supply circuit unit ex311 that supplies power to each unit. In addition to the operation input unit ex312, the interface unit ex317 includes a bridge unit ex313 connected to an external device such as a reader / recorder ex218, a recording unit ex216 such as an SD card, and an external recording unit such as a hard disk. A driver ex315 for connecting to a medium, a modem ex316 for connecting to a telephone network, and the like may be included. Note that the recording medium ex216 is capable of electrically recording information by using a nonvolatile / volatile semiconductor memory element to be stored. Each part of the television ex300 is connected to each other via a synchronous bus.

First, a configuration in which the television ex300 decodes and reproduces multiplexed data acquired from the outside by the antenna ex204 and the like will be described. The television ex300 receives a user operation from the remote controller ex220 or the like, and demultiplexes the multiplexed data demodulated by the modulation / demodulation unit ex302 by the multiplexing / demultiplexing unit ex303 based on the control of the control unit ex310 having a CPU or the like. Furthermore, in the television ex300, the separated audio data is decoded by the audio signal processing unit ex304, and the separated video data is decoded by the video signal processing unit ex305 using the decoding method described in each of the above embodiments. The decoded audio signal and video signal are output from the output unit ex309 to the outside. At the time of output, these signals may be temporarily stored in the buffers ex318, ex319, etc. so that the audio signal and the video signal are reproduced in synchronization. Also, the television ex300 may read multiplexed data from recording media ex215 and ex216 such as a magnetic / optical disk and an SD card, not from broadcasting. Next, a configuration in which the television ex300 encodes an audio signal or a video signal and transmits the signal to the outside or to a recording medium will be described. The television ex300 receives a user operation from the remote controller ex220 and the like, encodes an audio signal with the audio signal processing unit ex304, and converts the video signal with the video signal processing unit ex305 based on the control of the control unit ex310. Encoding is performed using the encoding method described in (1). The encoded audio signal and video signal are multiplexed by the multiplexing / demultiplexing unit ex303 and output to the outside. When multiplexing, these signals may be temporarily stored in the buffers ex320, ex321, etc. so that the audio signal and the video signal are synchronized. Note that a plurality of buffers ex318, ex319, ex320, and ex321 may be provided as illustrated, or one or more buffers may be shared. Further, in addition to the illustrated example, data may be stored in the buffer as a buffer material that prevents system overflow and underflow, for example, between the modulation / demodulation unit ex302 and the multiplexing / demultiplexing unit ex303.

In addition to acquiring audio data and video data from broadcasts, recording media, and the like, the television ex300 has a configuration for receiving AV input of a microphone and a camera, and performs encoding processing on the data acquired from them. Also good. Here, the television ex300 has been described as a configuration capable of the above-described encoding processing, multiplexing, and external output, but these processing cannot be performed, and only the above-described reception, decoding processing, and external output are possible. It may be a configuration.

In addition, when reading or writing multiplexed data from a recording medium by the reader / recorder ex218, the decoding process or the encoding process may be performed by either the television ex300 or the reader / recorder ex218, The reader / recorder ex218 may share with each other.

As an example, FIG. 20 shows a configuration of the information reproducing / recording unit ex400 when data is read from or written to an optical disk. The information reproducing / recording unit ex400 includes elements ex401, ex402, ex403, ex404, ex405, ex406, and ex407 described below. The optical head ex401 irradiates a laser spot on the recording surface of the recording medium ex215 that is an optical disk to write information, and detects reflected light from the recording surface of the recording medium ex215 to read the information. The modulation recording unit ex402 electrically drives a semiconductor laser built in the optical head ex401 and modulates the laser beam according to the recording data. The reproduction demodulator ex403 amplifies the reproduction signal obtained by electrically detecting the reflected light from the recording surface by the photodetector built in the optical head ex401, separates and demodulates the signal component recorded on the recording medium ex215, and is necessary To play back information. The buffer ex404 temporarily holds information to be recorded on the recording medium ex215 and information reproduced from the recording medium ex215. The disk motor ex405 rotates the recording medium ex215. The servo controller ex406 moves the optical head ex401 to a predetermined information track while controlling the rotational drive of the disk motor ex405, and performs a laser spot tracking process. The system control unit ex407 controls the entire information reproduction / recording unit ex400. In the reading and writing processes described above, the system control unit ex407 uses various kinds of information held in the buffer ex404, and generates and adds new information as necessary, and the modulation recording unit ex402, the reproduction demodulation unit This is realized by recording / reproducing information through the optical head ex401 while operating the ex403 and the servo control unit ex406 in a coordinated manner. The system control unit ex407 is composed of, for example, a microprocessor, and executes these processes by executing a read / write program.

In the above, the optical head ex401 has been described as irradiating a laser spot. However, a configuration in which higher-density recording is performed using near-field light may be used.

FIG. 21 shows a schematic diagram of a recording medium ex215 that is an optical disk. Guide grooves (grooves) are formed in a spiral shape on the recording surface of the recording medium ex215, and address information indicating the absolute position on the disc is recorded in advance on the information track ex230 by changing the shape of the groove. This address information includes information for specifying the position of the recording block ex231 that is a unit for recording data, and the recording block is specified by reproducing the information track ex230 and reading the address information in a recording or reproducing apparatus. Can do. Further, the recording medium ex215 includes a data recording area ex233, an inner peripheral area ex232, and an outer peripheral area ex234. The area used for recording user data is the data recording area ex233, and the inner circumference area ex232 and the outer circumference area ex234 arranged on the inner or outer circumference of the data recording area ex233 are used for specific purposes other than user data recording. Used. The information reproducing / recording unit ex400 reads / writes encoded audio data, video data, or multiplexed data obtained by multiplexing these data with respect to the data recording area ex233 of the recording medium ex215.

In the above description, an optical disk such as a single-layer DVD or BD has been described as an example. However, the present invention is not limited to these, and an optical disk having a multilayer structure and capable of recording other than the surface may be used. Also, an optical disc with a multi-dimensional recording / reproducing structure, such as recording information using light of different wavelengths in the same place on the disc, or recording different layers of information from various angles. It may be.

Also, in the digital broadcasting system ex200, the car ex210 having the antenna ex205 can receive data from the satellite ex202 and the like, and the moving image can be reproduced on a display device such as the car navigation ex211 that the car ex210 has. The configuration of the car navigation ex211 may be, for example, a configuration in which a GPS receiving unit is added in the configuration shown in FIG.

FIG. 22A is a diagram showing the mobile phone ex114 using the moving picture decoding method and the moving picture encoding method described in the above embodiment. The mobile phone ex114 includes an antenna ex350 for transmitting and receiving radio waves to and from the base station ex110, a camera unit ex365 capable of capturing video and still images, a video captured by the camera unit ex365, a video received by the antenna ex350, and the like Is provided with a display unit ex358 such as a liquid crystal display for displaying the decrypted data. The mobile phone ex114 further includes a main body unit having an operation key unit ex366, an audio output unit ex357 such as a speaker for outputting audio, an audio input unit ex356 such as a microphone for inputting audio, a captured video, In the memory unit ex367 for storing encoded data or decoded data such as still images, recorded audio, received video, still images, mails, or the like, or an interface unit with a recording medium for storing data A slot ex364 is provided.

Furthermore, a configuration example of the mobile phone ex114 will be described with reference to FIG. 22B. The mobile phone ex114 has a power supply circuit part ex361, an operation input control part ex362, and a video signal processing part ex355 with respect to a main control part ex360 that comprehensively controls each part of the main body including the display part ex358 and the operation key part ex366. , A camera interface unit ex363, an LCD (Liquid Crystal Display) control unit ex359, a modulation / demodulation unit ex352, a multiplexing / demultiplexing unit ex353, an audio signal processing unit ex354, a slot unit ex364, and a memory unit ex367 are connected to each other via a bus ex370. ing.

When the end of call and the power key are turned on by a user operation, the power supply circuit unit ex361 starts up the mobile phone ex114 in an operable state by supplying power from the battery pack to each unit.

The cellular phone ex114 converts the audio signal collected by the audio input unit ex356 in the voice call mode into a digital audio signal by the audio signal processing unit ex354 based on the control of the main control unit ex360 having a CPU, a ROM, a RAM, and the like. Then, this is subjected to spectrum spread processing by the modulation / demodulation unit ex352, digital-analog conversion processing and frequency conversion processing are performed by the transmission / reception unit ex351, and then transmitted via the antenna ex350. The mobile phone ex114 also amplifies the received data received via the antenna ex350 in the voice call mode, performs frequency conversion processing and analog-digital conversion processing, performs spectrum despreading processing by the modulation / demodulation unit ex352, and performs voice signal processing unit After being converted into an analog audio signal by ex354, this is output from the audio output unit ex357.

Further, when an e-mail is transmitted in the data communication mode, the text data of the e-mail input by operating the operation key unit ex366 of the main unit is sent to the main control unit ex360 via the operation input control unit ex362. The main control unit ex360 performs spread spectrum processing on the text data in the modulation / demodulation unit ex352, performs digital analog conversion processing and frequency conversion processing in the transmission / reception unit ex351, and then transmits the text data to the base station ex110 via the antenna ex350. . In the case of receiving an e-mail, almost the reverse process is performed on the received data and output to the display unit ex358.

When transmitting video, still images, or video and audio in the data communication mode, the video signal processing unit ex355 compresses the video signal supplied from the camera unit ex365 by the moving image encoding method described in the above embodiments. Encode (that is, function as the image encoding apparatus of the present invention), and send the encoded video data to the multiplexing / demultiplexing unit ex353. The audio signal processing unit ex354 encodes the audio signal picked up by the audio input unit ex356 while the camera unit ex365 images a video, a still image, etc., and sends the encoded audio data to the multiplexing / separating unit ex353. To do.

The multiplexing / demultiplexing unit ex353 multiplexes the encoded video data supplied from the video signal processing unit ex355 and the encoded audio data supplied from the audio signal processing unit ex354 by a predetermined method, and is obtained as a result. The multiplexed data is subjected to spread spectrum processing by the modulation / demodulation unit (modulation / demodulation circuit unit) ex352, digital-analog conversion processing and frequency conversion processing by the transmission / reception unit ex351, and then transmitted via the antenna ex350.

Decode multiplexed data received via antenna ex350 when receiving video file data linked to a homepage, etc. in data communication mode, or when receiving e-mail with video and / or audio attached Therefore, the multiplexing / separating unit ex353 separates the multiplexed data into a video data bit stream and an audio data bit stream, and performs video signal processing on the video data encoded via the synchronization bus ex370. The encoded audio data is supplied to the audio signal processing unit ex354 while being supplied to the unit ex355. The video signal processing unit ex355 decodes the video signal by decoding using the video decoding method corresponding to the video encoding method shown in each of the above embodiments (that is, functions as the image decoding device of the present invention). For example, video and still images included in the moving image file linked to the home page are displayed from the display unit ex358 via the LCD control unit ex359. The audio signal processing unit ex354 decodes the audio signal, and the audio is output from the audio output unit ex357.

In addition to the transmission / reception type terminal having both the encoder and the decoder, the terminal such as the mobile phone ex114 is referred to as a transmission terminal having only an encoder and a receiving terminal having only a decoder. There are three possible mounting formats. Furthermore, in the digital broadcasting system ex200, it has been described that multiplexed data in which music data or the like is multiplexed with video data is received and transmitted, but data in which character data or the like related to video is multiplexed in addition to audio data It may be video data itself instead of multiplexed data.

As described above, the moving picture encoding method or the moving picture decoding method shown in each of the above embodiments can be used in any of the above-described devices / systems. The described effect can be obtained.

Further, the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.

(Embodiment 6)
The moving picture coding method or apparatus shown in the above embodiments and the moving picture coding method or apparatus compliant with different standards such as MPEG-2, MPEG4-AVC, and VC-1 are appropriately switched as necessary. Thus, it is also possible to generate video data.

Here, when a plurality of pieces of video data conforming to different standards are generated, it is necessary to select a decoding method corresponding to each standard when decoding. However, since it is impossible to identify which standard the video data to be decoded complies with, there arises a problem that an appropriate decoding method cannot be selected.

In order to solve this problem, multiplexed data obtained by multiplexing audio data or the like with video data is configured to include identification information indicating which standard the video data conforms to. A specific configuration of multiplexed data including video data generated by the moving picture encoding method or apparatus shown in the above embodiments will be described below. The multiplexed data is a digital stream in the MPEG-2 transport stream format.

FIG. 23 is a diagram showing a structure of multiplexed data. As shown in FIG. 23, multiplexed data is obtained by multiplexing one or more of a video stream, an audio stream, a presentation graphics stream (PG), and an interactive graphics stream. The video stream indicates the main video and sub-video of the movie, the audio stream (IG) indicates the main audio portion of the movie and the sub-audio mixed with the main audio, and the presentation graphics stream indicates the subtitles of the movie. Here, the main video indicates a normal video displayed on the screen, and the sub-video is a video displayed on a small screen in the main video. The interactive graphics stream indicates an interactive screen created by arranging GUI components on the screen. The video stream is encoded by the moving image encoding method or apparatus shown in the above embodiments, or the moving image encoding method or apparatus conforming to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1. ing. The audio stream is encoded by a method such as Dolby AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, or linear PCM.

Each stream included in the multiplexed data is identified by PID. For example, 0x1011 for video streams used for movie images, 0x1100 to 0x111F for audio streams, 0x1200 to 0x121F for presentation graphics, 0x1400 to 0x141F for interactive graphics streams, 0x1B00 to 0x1B1F are assigned to video streams used for sub-pictures, and 0x1A00 to 0x1A1F are assigned to audio streams used for sub-audio mixed with the main audio.

FIG. 24 is a diagram schematically showing how multiplexed data is multiplexed. First, a video stream ex235 composed of a plurality of video frames and an audio stream ex238 composed of a plurality of audio frames are converted into PES packet sequences ex236 and ex239, respectively, and converted into TS packets ex237 and ex240. Similarly, the data of the presentation graphics stream ex241 and interactive graphics ex244 are converted into PES packet sequences ex242 and ex245, respectively, and further converted into TS packets ex243 and ex246. The multiplexed data ex247 is configured by multiplexing these TS packets into one stream.

FIG. 25 shows in more detail how the video stream is stored in the PES packet sequence. The first row in FIG. 25 shows a video frame sequence of the video stream. The second level shows a PES packet sequence. As shown by arrows yy1, yy2, yy3, and yy4 in FIG. 25, a plurality of video presentation units in a video stream are divided into pictures, B pictures, and P pictures and stored in the payload of the PES packet. . Each PES packet has a PES header, and a PTS (Presentation Time-Stamp) that is a display time of a picture and a DTS (Decoding Time-Stamp) that is a decoding time of a picture are stored in the PES header.

FIG. 26 shows the format of the TS packet that is finally written in the multiplexed data. The TS packet is a 188-byte fixed-length packet composed of a 4-byte TS header having information such as a PID for identifying a stream and a 184-byte TS payload for storing data. The PES packet is divided and stored in the TS payload. The In the case of a BD-ROM, a 4-byte TP_Extra_Header is added to a TS packet, forms a 192-byte source packet, and is written in multiplexed data. In TP_Extra_Header, information such as ATS (Arrival_Time_Stamp) is described. ATS indicates the transfer start time of the TS packet to the PID filter of the decoder. Source packets are arranged in the multiplexed data as shown in the lower part of FIG. 26, and the number incremented from the head of the multiplexed data is called SPN (source packet number).

In addition, TS packets included in the multiplexed data include PAT (Program Association Table), PMT (Program Map Table), PCR (Program Clock Reference), and the like in addition to each stream such as video / audio / caption. PAT indicates what the PID of the PMT used in the multiplexed data is, and the PID of the PAT itself is registered as 0. The PMT has the PID of each stream such as video / audio / subtitles included in the multiplexed data and the attribute information of the stream corresponding to each PID, and has various descriptors related to the multiplexed data. The descriptor includes copy control information for instructing permission / non-permission of copying of multiplexed data. In order to synchronize the ATC (Arrival Time Clock), which is the ATS time axis, and the STC (System Time Clock), which is the PTS / DTS time axis, the PCR corresponds to the ATS in which the PCR packet is transferred to the decoder. Contains STC time information.

FIG. 27 is a diagram for explaining the data structure of the PMT in detail. A PMT header describing the length of data included in the PMT is arranged at the head of the PMT. After that, a plurality of descriptors related to multiplexed data are arranged. The copy control information and the like are described as descriptors. After the descriptor, a plurality of pieces of stream information regarding each stream included in the multiplexed data are arranged. The stream information includes a stream descriptor in which a stream type, a stream PID, and stream attribute information (frame rate, aspect ratio, etc.) are described to identify a compression codec of the stream. There are as many stream descriptors as the number of streams existing in the multiplexed data.

When recording on a recording medium or the like, the multiplexed data is recorded together with the multiplexed data information file.

As shown in FIG. 28, the multiplexed data information file is management information of multiplexed data, has a one-to-one correspondence with the multiplexed data, and includes multiplexed data information, stream attribute information, and an entry map.

The multiplexed data information includes a system rate, a reproduction start time, and a reproduction end time as shown in FIG. The system rate indicates a maximum transfer rate of multiplexed data to a PID filter of a system target decoder described later. The ATS interval included in the multiplexed data is set to be equal to or less than the system rate. The playback start time is the PTS of the first video frame of the multiplexed data, and the playback end time is set by adding the playback interval for one frame to the PTS of the video frame at the end of the multiplexed data.

In the stream attribute information, as shown in FIG. 29, attribute information about each stream included in the multiplexed data is registered for each PID. The attribute information has different information for each video stream, audio stream, presentation graphics stream, and interactive graphics stream. The video stream attribute information includes the compression codec used to compress the video stream, the resolution of the individual picture data constituting the video stream, the aspect ratio, and the frame rate. It has information such as how much it is. The audio stream attribute information includes the compression codec used to compress the audio stream, the number of channels included in the audio stream, the language supported, and the sampling frequency. With information. These pieces of information are used for initialization of the decoder before the player reproduces it.

In this embodiment, among the multiplexed data, the stream type included in the PMT is used. Also, when multiplexed data is recorded on the recording medium, video stream attribute information included in the multiplexed data information is used. Specifically, in the video encoding method or apparatus shown in each of the above embodiments, the video encoding shown in each of the above embodiments for the stream type or video stream attribute information included in the PMT. There is provided a step or means for setting unique information indicating that the video data is generated by the method or apparatus. With this configuration, it is possible to discriminate between video data generated by the moving picture encoding method or apparatus described in the above embodiments and video data compliant with other standards.

FIG. 30 shows steps of the moving picture decoding method according to the present embodiment. In step exS100, the stream type included in the PMT or the video stream attribute information included in the multiplexed data information is acquired from the multiplexed data. Next, in step exS101, it is determined whether or not the stream type or the video stream attribute information indicates multiplexed data generated by the moving picture encoding method or apparatus described in the above embodiments. To do. When it is determined that the stream type or the video stream attribute information is generated by the moving image encoding method or apparatus described in the above embodiments, in step exS102, the above embodiments are performed. Decoding is performed by the moving picture decoding method shown in the form. If the stream type or video stream attribute information indicates that it conforms to a standard such as conventional MPEG-2, MPEG4-AVC, or VC-1, in step exS103, the conventional information Decoding is performed by a moving image decoding method compliant with the standard.

In this way, by setting a new unique value in the stream type or video stream attribute information, whether or not decoding is possible with the moving picture decoding method or apparatus described in each of the above embodiments is performed. Judgment can be made. Therefore, even when multiplexed data conforming to different standards is input, an appropriate decoding method or apparatus can be selected, and therefore decoding can be performed without causing an error. In addition, the moving picture encoding method or apparatus or the moving picture decoding method or apparatus described in this embodiment can be used in any of the above-described devices and systems.

(Embodiment 7)
The moving picture encoding method and apparatus and moving picture decoding method and apparatus described in the above embodiments are typically realized by an LSI that is an integrated circuit. As an example, FIG. 31 shows a configuration of an LSI ex500 that is made into one chip. The LSI ex500 includes elements ex501, ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 described below, and each element is connected via a bus ex510. The power supply circuit unit ex505 is activated to an operable state by supplying power to each unit when the power supply is on.

For example, when performing the encoding process, the LSI ex500 performs the microphone ex117 and the camera ex113 by the AV I / O ex509 based on the control of the control unit ex501 including the CPU ex502, the memory controller ex503, the stream controller ex504, the drive frequency control unit ex512, and the like. The AV signal is input from the above. The input AV signal is temporarily stored in an external memory ex511 such as SDRAM. Based on the control of the control unit ex501, the accumulated data is divided into a plurality of times as appropriate according to the processing amount and the processing speed and sent to the signal processing unit ex507, and the signal processing unit ex507 encodes an audio signal and / or video. Signal encoding is performed. Here, the encoding process of the video signal is the encoding process described in the above embodiments. The signal processing unit ex507 further performs processing such as multiplexing the encoded audio data and the encoded video data according to circumstances, and outputs the result from the stream I / Oex 506 to the outside. The output multiplexed data is transmitted to the base station ex107 or written to the recording medium ex215. It should be noted that data should be temporarily stored in the buffer ex508 so as to be synchronized when multiplexing.

In the above description, the memory ex511 is described as an external configuration of the LSI ex500. However, a configuration included in the LSI ex500 may be used. The number of buffers ex508 is not limited to one, and a plurality of buffers may be provided. The LSI ex500 may be made into one chip or a plurality of chips.

In the above description, the control unit ex501 includes the CPU ex502, the memory controller ex503, the stream controller ex504, the drive frequency control unit ex512, and the like, but the configuration of the control unit ex501 is not limited to this configuration. For example, the signal processing unit ex507 may further include a CPU. By providing a CPU also in the signal processing unit ex507, the processing speed can be further improved. As another example, the CPU ex502 may be configured to include a signal processing unit ex507 or, for example, an audio signal processing unit that is a part of the signal processing unit ex507. In such a case, the control unit ex501 is configured to include a signal processing unit ex507 or a CPU ex502 having a part thereof.

In addition, although it was set as LSI here, it may be called IC, system LSI, super LSI, and ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of progress in semiconductor technology or other derived technology, it is naturally possible to integrate functional blocks using this technology. Biotechnology can be applied.

(Embodiment 8)
When decoding the video data generated by the moving picture encoding method or apparatus shown in the above embodiments, the video data conforming to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1 is decoded. It is conceivable that the amount of processing increases compared to the case. Therefore, in LSI ex500, it is necessary to set a driving frequency higher than the driving frequency of CPU ex502 when decoding video data compliant with the conventional standard. However, when the drive frequency is increased, there is a problem that power consumption increases.

In order to solve this problem, moving picture decoding devices such as the television ex300 and LSI ex500 are configured to identify which standard the video data conforms to and switch the driving frequency in accordance with the standard. FIG. 32 shows a configuration ex800 in the present embodiment. The drive frequency switching unit ex803 sets the drive frequency high when the video data is generated by the moving image encoding method or apparatus described in the above embodiments. Then, the decoding processing unit ex801 that executes the moving picture decoding method described in each of the above embodiments is instructed to decode the video data. On the other hand, when the video data is video data compliant with the conventional standard, compared to the case where the video data is generated by the moving picture encoding method or apparatus shown in the above embodiments, Set the drive frequency low. Then, it instructs the decoding processing unit ex802 compliant with the conventional standard to decode the video data.

More specifically, the drive frequency switching unit ex803 includes the CPU ex502 and the drive frequency control unit ex512 in FIG. Also, the decoding processing unit ex801 that executes the moving picture decoding method shown in each of the above embodiments and the decoding processing unit ex802 that complies with the conventional standard correspond to the signal processing unit ex507 in FIG. The CPU ex502 identifies which standard the video data conforms to. Then, based on the signal from the CPU ex502, the drive frequency control unit ex512 sets the drive frequency. Further, based on the signal from the CPU ex502, the signal processing unit ex507 decodes the video data. Here, for example, the identification information described in the sixth embodiment can be used for identifying the video data. The identification information is not limited to that described in the sixth embodiment, and any information that can identify which standard the video data conforms to may be used. For example, it is possible to identify which standard the video data conforms to based on an external signal that identifies whether the video data is used for a television or a disk. In some cases, identification may be performed based on such an external signal. In addition, the selection of the driving frequency in the CPU ex502 may be performed based on, for example, a lookup table in which video data standards and driving frequencies are associated with each other as shown in FIG. The look-up table is stored in the buffer ex508 or the internal memory of the LSI, and the CPU ex502 can select the drive frequency by referring to the look-up table.

FIG. 33 shows steps for executing the method of the present embodiment. First, in step exS200, the signal processing unit ex507 acquires identification information from the multiplexed data. Next, in step exS201, the CPU ex502 identifies whether the video data is generated by the encoding method or apparatus described in each of the above embodiments based on the identification information. When the video data is generated by the encoding method or apparatus shown in the above embodiments, in step exS202, the CPU ex502 sends a signal for setting the drive frequency high to the drive frequency control unit ex512. Then, the drive frequency control unit ex512 sets a high drive frequency. On the other hand, if it indicates that the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1, in step exS203, the CPU ex502 drives the signal for setting the drive frequency low. This is sent to the frequency control unit ex512. Then, in the drive frequency control unit ex512, the drive frequency is set to be lower than that in the case where the video data is generated by the encoding method or apparatus described in the above embodiments.

Furthermore, the power saving effect can be further enhanced by changing the voltage applied to the LSI ex500 or the device including the LSI ex500 in conjunction with the switching of the driving frequency. For example, when the drive frequency is set low, it is conceivable that the voltage applied to the LSI ex500 or the device including the LSI ex500 is set low as compared with the case where the drive frequency is set high.

In addition, the setting method of the driving frequency may be set to a high driving frequency when the processing amount at the time of decoding is large, and to a low driving frequency when the processing amount at the time of decoding is small. It is not limited to the method. For example, the amount of processing for decoding video data compliant with the MPEG4-AVC standard is larger than the amount of processing for decoding video data generated by the moving picture encoding method or apparatus described in the above embodiments. It is conceivable that the setting of the driving frequency is reversed to that in the case described above.

Furthermore, the method for setting the drive frequency is not limited to the configuration in which the drive frequency is lowered. For example, when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in the above embodiments, the voltage applied to the LSIex500 or the apparatus including the LSIex500 is set high. However, when it is shown that the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, VC-1, etc., it is also possible to set the voltage applied to the LSIex500 or the device including the LSIex500 low. It is done. As another example, when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in the above embodiments, the driving of the CPU ex502 is stopped. If the video data conforms to the standards such as MPEG-2, MPEG4-AVC, VC-1, etc., the CPU ex502 is temporarily stopped because there is room in processing. Is also possible. Even when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in each of the above embodiments, if there is a margin for processing, the CPU ex502 is temporarily driven. It can also be stopped. In this case, it is conceivable to set the stop time shorter than in the case where the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1.

Thus, it is possible to save power by switching the drive frequency according to the standard to which the video data conforms. In addition, when the battery is used to drive the LSI ex500 or the device including the LSI ex500, it is possible to extend the life of the battery with power saving.

(Embodiment 9)
A plurality of video data that conforms to different standards may be input to the above-described devices and systems such as a television and a mobile phone. As described above, the signal processing unit ex507 of the LSI ex500 needs to support a plurality of standards in order to be able to decode even when a plurality of video data complying with different standards is input. However, when the signal processing unit ex507 corresponding to each standard is used individually, there is a problem that the circuit scale of the LSI ex500 increases and the cost increases.

In order to solve this problem, a decoding processing unit for executing the moving picture decoding method shown in each of the above embodiments and a decoding conforming to a standard such as MPEG-2, MPEG4-AVC, or VC-1 The processing unit is partly shared. An example of this configuration is shown as ex900 in FIG. 35A. For example, the moving picture decoding method shown in each of the above embodiments and the moving picture decoding method compliant with the MPEG4-AVC standard are processed in processes such as entropy coding, inverse quantization, deblocking filter, and motion compensation. Some contents are common. For the common processing content, the decoding processing unit ex902 corresponding to the MPEG4-AVC standard is shared, and for the other processing content unique to the present invention not corresponding to the MPEG4-AVC standard, the dedicated decoding processing unit ex901 is used. Configuration is conceivable. In particular, since the present invention is characterized by inverse transformation, for example, a dedicated decoding processing unit ex901 is used for inverse transformation, and other entropy coding, inverse quantization, deblocking filter, motion, etc. It is conceivable to share the decoding processing unit for any or all of the compensation. Regarding the sharing of the decoding processing unit, regarding the common processing content, the decoding processing unit for executing the moving picture decoding method described in each of the above embodiments is shared, and the processing content specific to the MPEG4-AVC standard As for, a configuration using a dedicated decoding processing unit may be used.

Further, ex1000 in FIG. 35B shows another example in which processing is partially shared. In this example, a dedicated decoding processing unit ex1001 corresponding to processing content unique to the present invention, a dedicated decoding processing unit ex1002 corresponding to processing content specific to other conventional standards, and a moving picture decoding method of the present invention A common decoding processing unit ex1003 corresponding to processing contents common to other conventional video decoding methods is used. Here, the dedicated decoding processing units ex1001 and ex1002 are not necessarily specialized in the processing content specific to the present invention or other conventional standards, and may be capable of executing other general-purpose processing. Also, the configuration of the present embodiment can be implemented by LSI ex500.

As described above, by sharing the decoding processing unit with respect to the processing contents common to the moving picture decoding method of the present invention and the moving picture decoding method of the conventional standard, the circuit scale of the LSI is reduced, and the cost is reduced. It is possible to reduce.

The decoding method according to the present invention can be used in, for example, a television, a digital video recorder, a car navigation, a mobile phone, a digital camera, or a digital video camera.

120, 912 Transformer 130, 913 Quantizer 140, 914 Inverse quantizer 150, 915 Inverse transformer 190, 919 Entropy encoder 240, 924 Entropy decoder 300, 930 Transform controller 504, 604, 704

Claims (5)

1. A decoding method for decoding an encoded signal, comprising:
   Entropy decoding to perform entropy decoding on the encoded signal to generate quantized coefficients and prediction modes;
   Based on the prediction mode, it outputs information for controlling each of horizontal transformation and vertical transformation in the separation type inverse orthogonal transformation, and outputs transformation control information which is information indicating the first mode or the second mode. A conversion control step;
   An inverse quantization step of inversely quantizing the quantization coefficient to generate a decoded transformed output signal;
   An inverse orthogonal transformation step that sequentially performs horizontal transformation and vertical transformation in the separation type inverse orthogonal transformation on the decoded transformation output signal,
   In the inverse orthogonal transform step, in each of the horizontal transform and the vertical transform,
   When the transform control information indicates the first mode, the inverse orthogonal transform is performed on the decoded transform output signal of N (N is a natural number) points by N-point discrete cosine inverse transform,
   When the transform control information indicates the second mode, the inverse orthogonal transform is performed by 2N-point discrete sine transform on the N-point decoded transform output signal.
2. The inverse orthogonal transform used in the second mode is
   A butterfly operation step for performing a butterfly operation on the input signal;
   An addition result conversion step of performing N / 2-point discrete cosine transformation Type-4 on the addition result of the output of the butterfly operation;
   A subtraction result conversion step for recursively executing the inverse orthogonal transform used in the second mode on the subtraction result of the output of the butterfly operation;
   And a post-conversion step of performing rearrangement and sign change on the output of the addition result conversion step and the output of the subtraction result conversion step, and outputting an N-point inverse conversion output signal. The decoding method according to 1.
3. A decoding method for decoding an encoded signal, comprising:
   Entropy decoding to perform entropy decoding on the encoded signal to generate quantized coefficients and prediction modes;
   Based on the prediction mode, it outputs information for controlling each of horizontal transformation and vertical transformation in the separation type inverse orthogonal transformation, and outputs transformation control information which is information indicating the first mode or the second mode. A conversion control step;
   An inverse quantization step of inversely quantizing the quantization coefficient to generate a decoded transformed output signal;
   An inverse orthogonal transformation step that sequentially performs horizontal transformation and vertical transformation in the separation type inverse orthogonal transformation on the decoded transformation output signal,
   In the inverse orthogonal transform step, in each of the horizontal transform and the vertical transform,
   When the transform control information indicates the first mode, the inverse orthogonal transform is performed on the decoded transform output signal of N (N is a natural number) points by N-point discrete cosine inverse transform,
   When the transform control information indicates the second mode, the inverse orthogonal transform is performed by N-point discrete sine transform on the N-point decoded transform output signal.
4. The decoding method according to claim 3, wherein the discrete sine transform used in the inverse orthogonal transform is DST-Type2.
5. The decoding method according to claim 3, wherein the discrete sine transform used in the inverse orthogonal transform is DST-Type4.
   

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