JP4655791B2 - Encoding apparatus, encoding method and program thereof - Google Patents

Description

  The present invention relates to a moving image data encoding apparatus, encoding method, and program thereof.

  In recent years, MPEG (compressed by orthogonal transform such as discrete cosine transform and motion compensation is used for the purpose of efficiently transmitting and storing information, and using redundancy unique to image information. H. Moving Picture Experts Group) H.264 / AVC (Advanced Video Coding) and other encoding devices and decoding devices that are compliant with an encoding method are becoming widespread in both information distribution such as broadcasting stations and information reception in general households.

By the way, in the conventional encoding device, each picture constituting the moving image data according to a GOP (Grope Of Pictures) structure corresponding to a predetermined M value without considering the characteristics of the moving image data to be encoded. I, P, and B picture types are assigned to data.
Here, the M value is a value indicating the interval between P slices (P pictures), that is, the number of picture intervals between I pictures.

  However, since the above-described conventional encoding apparatus performs encoding with a GOP structure corresponding to a predetermined M value without considering the characteristics of moving image data to be encoded, it has sufficiently high encoding efficiency. There is a problem that cannot be obtained.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an encoding device, an encoding method, and a program thereof that can further increase the encoding efficiency of moving images.

The encoding apparatus according to the present invention includes a scene change detection means for determining whether or not each of a plurality of picture data constituting moving image data to be encoded is picture data immediately after a scene change, and the scene change detection Based on the determination result of the means, a scene change position is specified from the plurality of picture data, and for each scene defined by the scene change position, predicted picture data obtained from the picture data and its reference picture data, Correlation level detection means for detecting a total value for each scene of pixel value differences between the picture data as a correlation level between the picture data and the reference picture data when the plurality of picture data is inter-coded When the respective scene, the picture data and the picture of the picture data Difficulty level detection means for detecting a total value of each pixel value difference between the predicted image data and the encoded image data as a difficulty level of intra-frame encoding of the picture data; and for each scene, the correlation level M value determining means for generating index data proportional to the correlation detected by the detecting means and inversely proportional to the difficulty detected by the difficulty detecting means, and determining a smaller M value as the index data becomes smaller; And a picture type determining means for determining a picture type of the picture data based on the M value determined by the M value determining means.

An encoding method according to the present invention is an encoding method of an encoding device having scene change detection means, correlation degree detection means, difficulty detection means, M value determination means, and picture type determination means. A first step in which the scene change detecting means determines whether or not each of a plurality of picture data constituting moving image data to be encoded is picture data immediately after a scene change; and the correlation degree detection A means identifies a scene change position from among the plurality of picture data based on the determination result in the first step, and for each scene defined by the scene change position, the picture data and its reference picture data The plurality of picture data are inter-coded with the total value for each scene of the pixel value difference from the predicted image data obtained from A second step of detecting the correlation between the picture data and the reference picture data, and the difficulty level detection means, for each scene, the picture data and an intra-picture code of the picture data A third step of detecting a total value for each scene of a difference in pixel value between the predicted image data and the predicted image data as the degree of difficulty of intra-frame encoding of the picture data; and the M value determining means, For the scene, index data that is proportional to the degree of correlation detected in the second step and inversely proportional to the degree of difficulty detected in the third step is generated, and the M value decreases as the index data decreases. And a picture type of the picture data is determined based on the M value determined in the fourth process. That has a fifth step.

The program of the present invention is a program that is executed by a computer included in an encoding device that encodes moving image data, and for each of a plurality of picture data constituting the moving image data to be encoded, A scene change position is specified from the plurality of picture data based on a first procedure for determining whether or not the data is picture data and a determination result in the first procedure, and is defined by the scene change position. For each scene, a total value for each scene of a difference in pixel values between the picture data and predicted image data obtained from the reference picture data is obtained when the plurality of picture data are inter-coded. A second procedure for detecting the correlation between the picture data and the reference picture data; A total value of each pixel value difference between the picture data and the predicted image data obtained by intra-picture coding of the picture data is detected as a difficulty level of intra-frame coding of the picture data. Generating index data that is proportional to the degree of correlation detected in the second procedure and inversely proportional to the degree of difficulty detected in the third procedure for each scene and the third procedure; A fourth procedure for determining a smaller M value as the data becomes smaller; and a fifth procedure for determining a picture type of the picture data based on the M value determined in the fourth procedure. Let the computer run.

  According to the present invention, it is possible to provide an encoding device, an encoding method, and a program thereof that can further increase the encoding efficiency of moving images.

Hereinafter, a communication system according to an embodiment of the present invention will be described.
First, the relationship between the configuration of the present embodiment and the configuration of the present invention will be described.
The trial motion prediction / compensation circuit 51 shown in FIG. 2 is an example of the correlation degree detecting means and the difficulty degree detecting means of the present invention.
The picture type assignment circuit 54 is an example of the picture type determination means of the present invention.
The optimum M determination circuit 53 is an example of the M value determination means of the present invention.

FIG. 1 is a conceptual diagram of a communication system 1 according to the present embodiment.
As shown in FIG. 1, the communication system 1 includes an encoding device 2 provided on the transmission side and a decoding device 3 provided on the reception side.

In the communication system 1, the encoding device 2 on the transmission side generates frame image data (bit stream) compressed by orthogonal transformation such as discrete cosine transformation and Karhunen-Labe transformation and motion compensation, and modulates the frame image data. Later, it is transmitted via a transmission medium such as a satellite broadcast wave, a cable TV network, a telephone line network, or a mobile phone line network.
On the receiving side, after the image signal received by the decoding device 3 is demodulated, frame image data expanded by inverse transformation of orthogonal transformation and motion compensation at the time of the modulation is generated and used.
The transmission medium may be a recording medium such as an optical disk, a magnetic disk, and a semiconductor memory.

<Encoder 2>
Hereinafter, the encoding device 2 shown in FIG. 1 will be described.
FIG. 2 is an overall configuration diagram of the encoding device 2 shown in FIG.
As shown in FIG. 2, the encoding device 2 includes, for example, an A / D conversion circuit 21, a screen rearrangement circuit 23, an arithmetic circuit 31, an orthogonal transformation circuit 32, a quantization circuit 33, a rate control circuit 34, and a lossless encoding. Circuit 35, buffer memory 36, inverse quantization circuit 37, inverse orthogonal transform circuit 38, addition circuit 39, deblock filter 40, frame memory 41, intra prediction circuit 42, motion prediction / compensation circuit 43, trial motion prediction / compensation circuit 51, an SC (Scene Change) detection circuit 52, an optimum M determination circuit 53, and a picture type assignment circuit 54.

In the encoding device 2, by using the trial motion prediction / compensation circuit 51 and the SC detection circuit 52, as shown in FIG. 3, the correlation between the picture data is detected in units of the macroblock MB and the statistic is calculated. At the same time, a statistic of the difficulty level of intra-frame coding of each macroblock MB is calculated.
Then, the optimum M decision circuit 53 decides the M value based on these statistics so that high coding efficiency can be obtained, and the picture type assignment circuit 54 uses the decided M value for each picture data. The picture type is determined.
In the present embodiment, the picture data is frame data or field data.

Hereinafter, components of the encoding device 2 will be described.
[A / D conversion circuit 21]
The A / D conversion circuit 21 converts the original image signal S10 composed of the input analog luminance signal Y and color difference signals Pb and Pr into digital original picture data, which is converted into the screen rearrangement circuit 23 and the trial motion. Output to the prediction / compensation circuit 51.

[Screen rearrangement circuit 23]
The screen rearrangement circuit 23 encodes the picture data generated by the A / D conversion circuit 21 according to a GOP (Group Of Pictures) structure composed of picture types I, P, and B assigned by the picture type assignment circuit 54. The data are rearranged in the order of output and output to the arithmetic circuit 31, intra prediction circuit 42 and motion prediction / compensation circuit 43.

[Arithmetic circuit 31]
The arithmetic circuit 31 generates image data indicating a difference between the picture data to be encoded input from the screen rearrangement circuit 23 and the predicted image data PI input from the intra prediction circuit 42 or the motion prediction / compensation circuit 43. This is output to the orthogonal transformation circuit 32.

[Orthogonal transformation circuit 32]
The orthogonal transform circuit 32 generates image data (for example, DCT coefficient) indicating transform coefficients by performing orthogonal transform such as discrete cosine transform (DCT) or Karhunen-Loeve transform on the image data input from the arithmetic circuit 31. This is output to the quantization circuit 33.

[Quantization circuit 33]
The quantization circuit 33 quantizes the image data (transform coefficient before quantization) input from the orthogonal transform circuit 32 based on the quantization scale QS input from the rate control circuit 34, and indicates the transform coefficient after quantization. Image data is generated and output to the lossless encoding circuit 35 and the inverse quantization circuit 37.

[Rate control circuit 34]
For example, the rate control circuit 34 generates a quantization scale QS based on the image data read from the buffer memory 36, and outputs this to the quantization circuit 33.

[Reversible encoding circuit 35]
The lossless encoding circuit 35 stores the image data obtained by variable-length encoding the image data input from the quantization circuit 33 in the buffer 36.
At this time, the lossless encoding circuit 35 uses the motion vector MV input from the motion prediction / compensation circuit 43 or its differential motion vector, identification data of the reference image data, and the intra prediction mode input from the intra prediction circuit 42 as header data or the like. To store.

[Buffer memory 36]
The image data stored in the buffer memory is modulated and transmitted as image data S2.
The image data S2 is decoded by the decoding device 3 as will be described later.
[Inverse quantization circuit 37]
The inverse quantization circuit 37 performs an inverse quantization process corresponding to the quantization of the quantization circuit 33 on the image data from the quantization circuit 33 to generate data obtained by the inverse quantization process. It outputs to the circuit 38.
[Inverse orthogonal transform circuit 38]
The inverse orthogonal transform circuit 38 outputs the image data generated by performing the inverse transform of the orthogonal transform in the orthogonal transform circuit 32 to the data input from the inverse quantization circuit 37 to the adder circuit 39.

[Addition circuit 39]
The adder circuit 33 adds (decodes) the image data input (decoded) from the inverse orthogonal transform circuit 38 and the predicted image data PI input from the intra prediction circuit 42 or the motion prediction / compensation circuit 43 to be referred (reconstructed). Picture data is generated and output to the deblocking filter 40.

[Deblock filter 40]
The deblocking filter 40 removes block distortion of the reference picture data input from the addition circuit 39 and writes it in the frame memory 41.

[Intra prediction circuit 42]
The intra prediction circuit 42 determines the intra prediction mode and the block size of the prediction block that minimize the residual in the macroblock to be intra-coded.
The intra prediction circuit 42 uses 4 × 4 and 16 × 16 pixels as the block size.
The intra prediction circuit 42 outputs predicted image data PI based on intra prediction to the arithmetic circuit 31 and the addition circuit 39 when intra prediction is selected.

[Motion prediction / compensation circuit 43]
The motion prediction / compensation circuit 43 performs motion prediction based on the reference picture data REF that has been locally decoded and stored in the frame memory 41 after encoding, and a motion vector that minimizes the residual and a block size for motion compensation To decide.
The motion prediction / compensation circuit 43 uses 16 × 16, 16 × 8, 8 × 16, 8 × 8, 8 × 4, 4 × 8, and 4 × 4 pixels as block sizes.
When the inter prediction is selected, the motion prediction / compensation circuit 43 outputs the predicted image data PI by the inter prediction to the arithmetic circuit 31 and the addition circuit 39.

[Trial Motion Prediction / Compensation Circuit 51]
For each macroblock MB in each original picture data input from the A / D conversion circuit 21, the trial motion prediction / compensation circuit 51, as shown in the following formula (1), the pixel data Org (i , N, x, y) and index data interAD (i, indicating the sum of absolute values of the differences between the pixel data interPred (i, n, x, y) of the macro block MB of the inter prediction image corresponding thereto. n) is calculated.
At this time, the trial motion prediction / compensation circuit 51 uses “1” as the M value.
In the present embodiment, the M value is a value indicating how many P-pictures are arranged between P-slices (P-pictures), that is, between I-pictures.
Here, i indicates the number of picture data, and n indicates the number of the macroblock MB.
Abs represents an absolute value.

(Equation 1)
interAD (i, n) = Σabs (Org (i, n, x, y) −interPred (i, n, x, y))
... (1)

  Further, the trial motion prediction / compensation circuit 51, for each macroblock MB in each original picture data input from the A / D conversion circuit 21, pixel data of the macroblock MB and pixel data of the intra prediction macroblock MB. The absolute value sum IND (i, n) of the differences is calculated.

For each picture data, the trial motion prediction / compensation circuit 51 calculates INTER_AD (i) indicating the sum of the index data interAD (i, n) of all (N) macroblocks MB in the picture data. Is output to the optimum M determination circuit 53.
Further, the trial motion prediction / compensation circuit 51 calculates, for each picture data, a sum IND (i) of the absolute value sums IND (i, n) for all the macroblocks MB in the picture data. Output to the optimum M determination circuit 53.

The trial motion prediction / compensation circuit 51 outputs the original picture data input from the A / D conversion circuit 21 to the SC detection circuit 52.
Further, the trial motion prediction / compensation circuit 51 outputs the calculated index data interAD (i, n) to the SC detection circuit 52, for example.

[SC detection circuit 52]
Based on the index data interAD (i, n) input from the trial motion prediction / compensation circuit 51, the SC detection circuit 52 determines whether each picture data is the picture data immediately after the scene change SC. The determination result RSC is output to the optimum M determination circuit 53.

[Optimum M Determination Circuit 53]
As shown in FIG. 4, the optimum M determination circuit 53 specifies a scene change position from a plurality of series of picture data based on the determination result RSC from the SC detection circuit 52, and sets the specified scene change position to the specified scene change position. For each scene defined accordingly, the index data X is calculated by dividing the sum of INTER_AD (i) of the picture data belonging to the scene by the sum of IND (i), as shown in the following equation (2).

(Equation 2)
X = (sum of INTER_AD (i)) / (sum of IND (i))
... (2)

The optimum M determination circuit 53 assigns “1” as the M value when the calculated index data X is equal to or less than the threshold value TH, and assigns “2” or “3” as the M value in other cases. .
In the other cases, the optimum M determination circuit 53 may assign only “2” as the M value.
In the present embodiment, the threshold value TH is determined experimentally.

[Picture type assignment circuit 54]
The picture type assignment circuit 54 assigns any one of I, P, and B picture types to the original picture data input from the SC detection circuit 52.
At this time, if the M value input from the optimum M determination circuit 53 indicates “1”, the picture type assignment circuit 54 assigns the picture type P to all the picture data other than the I picture data in the scene to be processed. Assign.
In addition, when the M value input from the optimum M determination circuit 53 indicates “2”, the picture type assignment circuit 54 adds picture types P and B to picture data other than I picture data in the scene to be processed. Are assigned alternately.

Hereinafter, an example of an operation for determining the M value in the encoding device 2 will be described.
FIG. 5 and FIG. 6 are flowcharts for explaining an operation example for determining the M value in the encoding device 2.
Step ST11:
For each macroblock MB in each original picture data input from the A / D conversion circuit 21, the trial motion prediction / compensation circuit 51, as shown in the above equation (1), the pixel data Org (i , N, x, y) and index data interAD (i, n) indicating the sum of the differences between the corresponding pixel data interPred (i, n, x, y) of the macro block MB of the inter predicted image. .
At this time, the trial motion prediction / compensation circuit 51 uses “1” as the M value.

Step ST12:
The trial motion prediction / compensation circuit 51, for each macroblock MB in each original picture data input from the A / D conversion circuit 21, MeanOrg (i, n) indicating an average value of pixel data constituting the macroblock MB. Is calculated.
Then, the trial motion prediction / compensation circuit 51 calculates the absolute value sum IND (i, n) for all the macroblocks MB in the picture data for each picture data.

Step ST13:
For each picture data, the trial motion prediction / compensation circuit 51 calculates INTER_AD (i) indicating the sum of the index data interAD (i, n) of all (N) macroblocks MB in the picture data. Is output to the optimum M determination circuit 53.

Step ST14:
The trial motion prediction / compensation circuit 51 calculates, for each picture data, IND (i) indicating the sum of the absolute value sums IND (i, n) of all the macroblocks MB in the picture data, which is optimal. The data is output to the M determination circuit 53.

Step ST15:
Based on the index data interAD (i, n) input from the trial motion prediction / compensation circuit 51, the SC detection circuit 52 determines whether each picture data is the picture data immediately after the scene change SC. The determination result RSC is output to the optimum M determination circuit 53.

Step ST16:
As shown in FIG. 4, the optimum M determination circuit 53 specifies a scene change position from a plurality of series of picture data based on the determination result RSC from the SC detection circuit 52, and sets the specified scene change position to the specified scene change position. For each scene defined accordingly, the index data X is calculated by dividing the sum of INTER_AD (i) of the picture data belonging to the scene by the sum of IND (i), as shown in the above equation (3).

Step ST17:
The optimum M determination circuit 53 determines whether or not the index data X calculated in step ST16 is equal to or less than the threshold value TH. If the optimum M determination circuit 53 determines that the index data X is equal to or less than the threshold value TH, the process proceeds to step ST18. If so, the process proceeds to step ST19.

Step ST18:
The optimum M determination circuit 53 assigns “1” as the M value.

Step ST19:
The optimum M determination circuit 53 assigns “2” or “3” as the M value.

Hereinafter, the overall operation of the encoding apparatus 2 shown in FIG. 2 will be described.
The input image signal is first converted into digital original picture data by the A / D conversion circuit 21 and output to the screen rearrangement circuit 23 and the trial motion prediction / compensation circuit 51.
Then, in the trial motion prediction / compensation circuit 51, the SC detection circuit 52, and the optimum M determination circuit 53, the M value is determined by the procedure shown in FIGS.
Next, the picture type assignment circuit 54 assigns a picture type based on the determined M value. Subsequently, in the screen rearrangement circuit 23, the picture data is rearranged in accordance with the GOP structure of the image compression information, and the picture data obtained thereby is used as the arithmetic circuit 31, the intra prediction circuit 42, and the motion prediction / compensation. It is output to the circuit 43.
Then, the arithmetic circuit 31 generates a difference image between the picture data from the screen rearrangement circuit 23 and the predicted image data PI from the intra prediction circuit 42 or the motion prediction / compensation circuit 43, and outputs this to the orthogonal transform circuit 32. Is done.

Then, in the orthogonal transform circuit 32, the quantization circuit 33, the inverse quantization circuit 37, and the inverse orthogonal transform circuit 38, the difference image is subjected to orthogonal transform, quantization, inverse quantization, and inverse orthogonal transform, and is output to the adder circuit 39. The
Then, in the adder circuit 39, the predicted image data PI from the intra prediction circuit 42 or the motion prediction / compensation circuit 43 and the difference image from the inverse orthogonal transform circuit 38 are reconstructed, and the reconstructed image is decoded as reference image data. It is written into the frame memory 41 via the block filter 40.
Then, the intra prediction circuit 42 performs intra prediction and generates predicted image data PI.
Further, the motion prediction / compensation circuit 43 generates predicted image data PI based on the reference image data REF stored in the frame memory 41.
Then, among the predicted image data PI generated by the intra prediction circuit 42 and the motion prediction / compensation circuit 43, predicted image data PI with higher encoding efficiency is selected and output to the arithmetic circuit 31.

As described above, the encoding device 2 determines an optimum M value according to the characteristics of the picture data of the moving image data to be encoded, and the picture type assignment circuit 54 determines the picture data based on the M value. Determine the picture type.
Therefore, according to the encoding device 2, it is possible to perform encoding with a GOP structure suitable for specifying picture data, and it is possible to increase the encoding efficiency as compared with the conventional case.

<Modification 1>
In the above-described embodiment, the trial motion prediction / compensation circuit 51 uses the index data interAD indicating the sum of the pixel data differences between the macroblock MB of the original picture data to be processed and the macroblock MB of the inter predicted image. (I, n) is used, but instead, the absolute value sum of the pixel data difference between the macro block MB of the processing target picture data and the macro block MB of the picture data with the previous display order is calculated. It may be used.
Further, the trial motion prediction / compensation circuit 51 replaces the index data interAD (i, n) with pixel data between the macroblock MB of the picture data to be processed and the macroblock MB of the inter predicted image. The total value of the DC component or AC component after DCT or FFT conversion of the difference may be used.
Further, the trial motion prediction / compensation circuit 51 may use the sum of absolute values of each element of the motion vector of the macro block MB to be processed instead of the index data interAD (i, n).

<Modification 2>
In the embodiment described above, the trial value motion prediction / compensation circuit 51 uses the absolute value sum IND (i). Instead, the pixel data Org (i, i, i) of each macro block MB in the original picture data to be processed is used. n, x, y) and index data Mad (i, n) indicating the sum of absolute values of the difference between the average value MeanOrg (i, n) may be used.
In addition, the trial motion prediction / compensation circuit 51 uses the pixel data difference between the macroblock MB of the processing target picture data and the macroblock MB of the intra-predicted image instead of the absolute value sum IND (i). The total value of the DC component or AC component after DCT or FFT conversion may be used.
Further, the trial motion prediction / compensation circuit 51 replaces the absolute value sum IND (i) with the variance value of the pixel data in the macroblock MB to be processed, or the maximum value of the pixel data in the macroblock MB or A difference between the minimum values may be used.

The present invention is not limited to the embodiment described above.
That is, those skilled in the art may make various modifications, combinations, subcombinations, and alternatives regarding the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.
For example, all or part of the functions of the encoding device 2 described above are executed by a processing circuit 253 such as a CPU (Central Processing Unit) according to the description of the program PRG stored in the memory 252 as shown in FIG. Also good.
In this case, the image data to be encoded is input via the interface 251 and the processing result is output.

  In the above-described embodiment, the optimum M determination circuit 53 may assign “1” or “2” as the M value based on the index data X, or assign a value “3” or more. The number of threshold values used for M value assignment may be two or more.

FIG. 1 is a configuration diagram of a communication system according to an embodiment of the present invention. FIG. 2 is a functional block diagram of the encoding apparatus shown in FIG. FIG. 3 is a diagram for explaining the processing of the trial motion prediction / compensation circuit 51 shown in FIG. FIG. 4 is a diagram for explaining processing of SC detection circuit 52 and optimum M determination circuit 53 shown in FIG. FIG. 5 is a flowchart for explaining an operation example for determining the M value in the encoding apparatus shown in FIG. FIG. 6 is a continuation flowchart of FIG. 5 for describing an operation example of determining the M value in the encoding apparatus shown in FIG. FIG. 7 is a diagram for explaining a modification of the encoding device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Communication system, 2 ... Encoding apparatus, 3 ... Decoding apparatus, 21 ... A / D conversion circuit, 23 ... Screen rearrangement circuit, 31 ... Operation circuit, 32 ... Orthogonal transformation circuit, 33 ... Quantization circuit, 34 ... Rate control circuit, 35 ... Lossless encoding circuit, 36 ... Buffer memory, 37 ... Inverse quantization circuit, 38 ... Inverse orthogonal transform circuit, 39 ... Adder circuit, 40 ... Deblock filter, 41 ... Frame memory, 42 ... Intra prediction Circuit 43... Motion prediction / compensation circuit 51 .. trial motion prediction / compensation circuit 52. SC detection circuit 53. Optimum M determination circuit 54.

Claims (6)

Scene change detection means for determining whether each of a plurality of picture data constituting moving image data to be encoded is picture data immediately after a scene change;
Based on the judgment result of the scene change detection means, a scene change position is specified from the plurality of picture data, and each scene defined by the scene change position is obtained from the picture data and its reference picture data. The total value for each scene of the difference in pixel value from the predicted image data is detected as the degree of correlation between the picture data and the reference picture data when the plurality of picture data is inter-coded. Correlation degree detection means;
For each scene, the total value of each pixel value difference between the picture data and the predicted image data obtained by intra-picture coding of the picture data is detected as the difficulty level of intra-frame coding of the picture data. A difficulty level detection means to
For each scene, index data that is proportional to the correlation degree detected by the correlation degree detection unit and inversely proportional to the difficulty level detected by the difficulty level detection unit is generated, and the M value decreases as the index data decreases. M value determining means for determining
Picture type determining means for determining a picture type of the picture data based on the M value determined by the M value determining means;
An encoding device. The correlation degree detection means includes a total value of pixel values between the picture data and predicted image data obtained from the reference picture data, and a total value of DC components or AC components after orthogonally transforming the differences. And a sum of pixel value differences between the picture data and the picture data whose display order is the previous one with respect to the picture data, and an absolute value sum of each element of the motion vector of the picture data The encoding device according to claim 1, wherein one of them is detected as the correlation degree. The difficulty level detection means includes a pixel value of pixel data of the picture data and a total value of a first difference between the average value and predicted picture data obtained by intra-picture encoding of the picture data and the picture data. A total value of second differences of pixel values between the first and second values, a total value of DC components or AC components after orthogonal transformation of the second difference, a variance value of pixel values of the picture data, and the pixels The encoding device according to claim 1, wherein any one of a difference between a maximum value and a minimum value of the value is detected as the difficulty level. The encoding apparatus according to claim 1, further comprising: an encoding unit that encodes the picture data based on the picture type determined by the picture type determination unit. An encoding method for an encoding device, comprising: a scene change detection unit, a correlation detection unit, a difficulty detection unit, an M value determination unit, and a picture type determination unit,
A first step in which the scene change detection means determines whether or not each of a plurality of picture data constituting moving image data to be encoded is picture data immediately after a scene change;
The correlation degree detection unit specifies a scene change position from the plurality of picture data based on the determination result in the first step, and for each scene defined by the scene change position, the picture data and When the plurality of picture data are inter-coded, the total value for each scene of the pixel value difference between the predicted picture data obtained from the reference picture data and the reference picture data A second step of detecting as a degree of correlation with
The difficulty level detection means, for each scene, calculates a total value for each scene of a difference in pixel values between the picture data and predicted image data obtained by intra-picture encoding of the picture data in the frame of the picture data. A third step of detecting as the difficulty of encoding;
The M value determining means generates index data proportional to the degree of correlation detected in the second step and inversely proportional to the degree of difficulty detected in the third step for each scene; A fourth step of determining a smaller M value as the index data becomes smaller;
A fifth step in which the picture type determining means determines a picture type of the picture data based on the M value determined in the fourth step ;
An encoding method comprising: A program to be executed by a computer included in an encoding device that encodes moving image data ,
A first procedure for determining whether each of a plurality of picture data constituting moving image data to be encoded is picture data immediately after a scene change;
Based on the determination result in the first procedure, a scene change position is specified from the plurality of picture data, and each scene defined by the scene change position is obtained from the picture data and its reference picture data. the total value for each of the scenes of the difference in pixel values between the predicted image data, in a case where the plurality of picture data are inter-coded is detected as the degree of correlation and the picture data, and the reference picture data A second procedure ;
For each scene, the total value of each pixel value difference between the picture data and the predicted image data obtained by intra-picture coding of the picture data is detected as the difficulty level of intra-frame coding of the picture data. A third procedure to
For each scene, index data that is proportional to the degree of correlation detected in the second procedure and inversely proportional to the degree of difficulty detected in the third procedure is generated, and decreases as the index data decreases. A fourth procedure for determining the M value;
A fifth procedure for determining a picture type of the picture data based on the M value determined in the fourth procedure ;
A program for causing the computer to execute.

Images