JP2008252225A - Motion picture encoding device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion picture encoding device and a method that can perform scene change detection with a small computational quantity and suitably encode image data without specially using a storage device to store pixel values of an image. <P>SOLUTION: The ratio between the generated code amount of encoded data generated by encoding input image data and the area allocation code amount of each area is calculated to judge a picture of scene change according to the ratio, and when a picture of scene change is judged, a calculated picture allocation code amount is adjusted to determine quantization parameters for each microblock according to the adjusted picture allocation code amount. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a moving image encoding apparatus and method for encoding image data of a moving image.

  The image data of the moving image is converted to MPEG-2 or H.264. In a moving picture coding apparatus that performs coding using a coding scheme such as H.264, the coding complexity (difficulty level) depends on a generated code amount after coding of image data and a quantization scale (quantization coefficient) for each picture. ), And an assigned code amount for encoding the next picture is determined according to the complexity.

  In a conventional moving image encoding device, when a scene change in which the image content changes greatly occurs, the complexity of pictures before and after the change changes greatly, so the generated code amount and the quantization scale before the scene change are used. Since it is not appropriate to determine the allocated code amount for encoding the next picture according to the complexity calculated in the above, the complexity is reset to the initial value and the next picture is encoded according to the complexity after reset. The assigned code amount is determined.

As a conventional method for detecting a scene change, a screen is divided into a plurality of areas, and a large image change in which the difference value of the pixel values of the preceding and succeeding images is greater than or equal to a first threshold value is detected for each area. There is a method of determining a scene change when it is detected that the area of change is equal to or greater than a second threshold on one screen (see Patent Documents 1 and 2).
JP 2002-185817 A JP 2003-47004 A

  However, in a moving image encoding apparatus using such a conventional scene change detection method, a storage device for storing pixel values of an image is necessary for detecting a scene change. There is also a problem that the amount of calculation increases because a difference value is calculated for each pixel and compared with a threshold value.

  Therefore, the problem to be solved by the present invention includes the above-mentioned drawbacks as an example, scene change detection can be performed with a small amount of computation and image data without using a storage device for storing image pixel values. It is an object of the present invention to provide a moving picture coding apparatus and method capable of appropriately coding a video.

  The moving picture encoding apparatus according to the first aspect of the present invention includes an encoding unit that encodes input image data for each macroblock according to a quantization parameter to generate encoded data, and the input image data for each picture. Picture allocation code amount calculation means for calculating an allocation code amount as a picture allocation code amount, and quantization for determining a quantization parameter for each macroblock according to the picture allocation code amount calculated by the picture allocation code amount calculation means A parameter determination unit; a region allocation code amount calculation unit that divides the input image data into a plurality of regions for each picture and calculates an allocation code amount of each of the plurality of regions as a region allocation code amount; and the encoding unit. A ratio calculating means for calculating a ratio between a generated code amount of generated encoded data and a region allocation code amount for each region; Scene change determining means for determining a scene change picture according to the ratio calculated by the ratio calculating means, and when the scene change picture is determined by the scene change determining means, the picture allocation code amount calculating means is The calculated picture allocation code amount is adjusted, and the quantization parameter determining means determines the quantization parameter for each macroblock according to the adjusted picture allocation code amount.

  The moving image encoding method according to an eleventh aspect of the invention relates to an encoding step of generating input data by encoding input image data according to a quantization parameter for each macroblock, and for each picture of the input image data. A picture allocation code amount calculation step for calculating an allocation code amount as a picture allocation code amount, and a quantum for determining a quantization parameter for each macroblock according to the picture allocation code amount calculated in the picture allocation code amount calculation step A segmentation parameter determination step, a region allocation code amount calculation step of dividing the input image data into a plurality of regions for each picture and calculating an allocation code amount of each of the plurality of regions as a region allocation code amount, and the encoding step The ratio between the generated code amount of the encoded data generated in step 1 and the region allocation code amount is calculated for each region. A rate change step, and a scene change determination step for determining a scene change picture according to the ratio calculated in the ratio calculation step, and when the scene change picture is determined in the scene change determination step In the picture allocation code amount calculation step, the calculated picture allocation code amount is adjusted, and the quantization parameter determining means determines the quantization parameter for each macroblock according to the adjusted picture allocation code amount. It is characterized by that.

  According to the moving image encoding apparatus of the invention according to claim 1 and the moving image encoding method of the invention according to claim 11, the generated code amount of the encoded data actually generated by encoding the input image data and A ratio with the area allocation code amount for each area is calculated, and a scene change picture is determined according to the ratio. When the scene change picture is determined, the calculated picture allocation code amount is adjusted, and the quantization parameter for each macroblock is determined according to the adjusted picture allocation code amount. Therefore, unlike the conventional case, it is not necessary to use a storage device for storing the pixel value of a picture for scene change picture determination, and the difference value is calculated for each pixel and compared with a threshold value. Since no calculation is required, scene change detection can be performed with a small amount of calculation including ratio calculation, and image data can be encoded appropriately.

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

  FIG. 1 shows the configuration of a moving picture encoding apparatus according to the present invention. This moving image encoding apparatus includes an encoding unit 1 and a rate control unit 2.

  The encoding unit 1 includes an arithmetic unit 11, a DCT converter 12, a quantizer 13, a variable length encoder 14, a buffer 15, an inverse quantizer 16, an inverse DCT converter 17, an arithmetic unit 18, a frame memory 19, It consists of a motion compensator 20 and a motion vector detector 21, and performs, for example, encoding conforming to the MPEG2 standard.

  The computing unit 11 subtracts the predicted image data motion-compensated by the motion compensator 20 for each macroblock from the input image data, and outputs the difference data to the DCT converter 12. A macro block is each block obtained by dividing image data into, for example, 16 pixels × 16 pixels. Note that the processing blocks for converting the input image data into macroblocks are not shown in FIG. The DCT converter 12 performs two-dimensional discrete cosine transform on the output data of the calculator 11. The quantizer 13 quantizes the image data after DCT conversion using a quantization coefficient corresponding to a quantization parameter described later to generate quantized data, which is then converted into a variable length encoder 14 and an inverse quantizer. 16 is output. The variable length encoder 14 performs variable length encoding on the quantized data supplied from the quantizer 13 and the motion vector supplied from the motion vector detector 21, and outputs the encoded data as encoded data via the buffer 15. To do.

  The inverse quantizer 16 inversely quantizes the quantized data input from the quantizer 13 and outputs the quantized data to the inverse DCT converter 17. The inverse DCT converter 17 performs inverse DCT conversion on the dequantized data and supplies the result to the calculator 18. The arithmetic unit 18 adds the predicted image data motion-compensated by the motion compensator 20 and the error data input from the inverse DCT converter 17 to convert the converted image data into original image data. The data is supplied to the memory 19 and stored.

  The motion vector detector 21 detects the motion vector of the input image data with reference to the image data read from the frame memory 19, and outputs the motion vector to the variable length encoder 14 and the motion compensator 20. To do. The motion compensator 20 performs motion compensation on the image data read from the frame memory 19 in accordance with the motion vector to generate predicted image data.

  As shown in FIG. 2, the rate control unit 2 includes a picture allocation code amount calculation unit 26, a region allocation code amount calculation unit 27, a code amount ratio calculation unit 28, a scene change determination unit 29, and a quantization parameter determination unit 30. ing.

  The picture allocation code amount calculation unit 26 inputs a quantization parameter including a quantization coefficient used in the quantization immediately before the quantizer 13 and allocates a GOP code amount for each GOP, and for each picture of the input image data. An allocation code amount (picture allocation code amount) is calculated based on the target bit rate.

  GOP is an abbreviation for Group Of Picture. The input frame-unit image data is encoded as one of an intra picture (I picture), an inter picture (P picture), and a bi-directional picture (B picture) in the encoding unit 1, and the I picture 1 GOP is from the occurrence of the first I picture to the occurrence of the next I picture.

  The region allocation code amount calculation unit 27 receives the picture allocation code amount calculated by the picture allocation code amount calculation unit 26, divides one picture into a plurality of regions, and assigns an allocation code amount (region allocation code amount) for each region. calculate. As shown in FIG. 3, the plurality of areas are areas obtained by dividing one picture so that the number of macroblocks is constant in the encoding processing order. In this embodiment, the area is divided at equal intervals by a plurality of horizontal dividing lines. In the case of FIG. 3, 16 areas (area 0 to area 15) are formed. The number of divided areas is not limited to this.

  The code amount ratio calculation unit 28 inputs the region allocation code amount calculated by the region allocation code amount calculation unit 27, and further inputs the generated code amount of the encoded data generated by the variable length encoder 14. An actual generated code amount (region generated code amount) is obtained for each, and a ratio between the region allocation code amount and the region generated code amount is calculated. The scene change determination unit 29 receives the ratio from the code amount ratio calculation unit 28 and determines whether the picture is a scene change based on the ratio. The scene change determination result by the scene change determination unit 29 is supplied to the picture allocation code amount calculation unit 26.

  The quantization parameter determination unit 30 determines a quantization parameter for each macroblock according to the picture allocation code amount calculated by the picture allocation code amount calculation unit 26 and supplies it to the quantizer 13. The quantization parameter input to the picture allocation code amount calculation unit 26 is a quantization parameter of the same picture type before the quantization parameter of the macroblock determined by the quantization parameter determination unit 30.

  Next, a scene change determination process performed in the rate control unit 2 of the moving image encoding apparatus having the above configuration will be described.

  Here, it is assumed that one picture is divided into areas area0 to area15 as shown in FIG. 3, and the area allocation code amount calculation unit 27 calculates the area allocation code amount of each of the areas area0 to area15. The scene change determination process includes a first process and a second process.

In the first process, as shown in FIG. 4, first, when the area allocation code amount calculation unit 27 calculates the area allocation code amounts of the areas area0 to area15 of one picture in step S1, a variable N = 0 is set. (Step S2) Whether the ratio of the area areaN is calculated by the code amount ratio calculation unit 28 as the generated code amount / region allocation code amount (Step S3), and is the ratio larger than the threshold value I1 (first threshold value)? It is determined whether or not (step S4). Since the result of encoding based on the region allocation code amount is the region generation code amount, the region allocation code amount is temporally shifted from the region generation code amount by at least one region when calculating the ratio in step S3.
If the ratio> threshold value I1, the number of areas C1 is increased by 1 (step S5). The number of areas C1 is a value for counting areas where the ratio> threshold value I1 in one picture. If ratio ≦ threshold value I1, the current number of regions C1 is maintained. After the area number C1 is processed in this way, it is determined whether or not the area number C1 is larger than the threshold value I2 (second threshold value) (step S6). When the number of areas C1> threshold I2, it is determined that the scene has changed (step S7). If the number of regions C1 ≦ threshold I2, 1 is added to the variable N (step S8), and it is determined whether N is greater than 15 (step S9). If N ≦ 15, the process returns to step S3 and the above operation is repeated. Steps S4 to S7 are operations of the scene change determination unit 29.

  In the second process, as shown in FIG. 5, first, when the area allocation code amount calculation unit 27 calculates the area allocation code amount of each area area0 to area15 of one picture in step S11, a variable N = 0 is set. (Step S12) Whether the ratio for the area areaN is calculated by the code amount ratio calculation unit 28 as generated code amount / region assigned code amount (Step S13), and is the ratio smaller than the threshold value D1 (third threshold value)? It is determined whether or not (step S14). If the ratio <threshold value D1, the number of regions C2 is increased by 1 (step S15). The number of areas C2 is a value for counting the areas where the ratio <threshold value D1 in one picture. If the ratio ≧ the threshold value D1, the current area number C2 is maintained. After the area number C2 is processed in this way, it is determined whether or not the area number C2 is larger than the threshold value D2 (fourth threshold value) (step S16). When the number of areas C1> threshold value D2, it is determined that a scene change has been detected (step S17). If the number of regions C1 ≦ threshold D2, 1 is added to the variable N (step S18), and it is determined whether N is greater than 15 (step S19). If N ≦ 15, the process returns to step S13 and the above operation is repeated. Steps S14 to S17 are operations of the scene change determination unit 29.

  In the moving picture encoding apparatus according to the present invention, the scene change determination process is actually executed in combination with the encoding process. As an execution method thereof, there are a method that is executed every time the encoding process of one picture is completed, and a method that is executed during the encoding process of one picture.

  FIG. 6 shows an operation flow in the moving picture encoding apparatus every time one picture encoding process is completed. Here, one GOP is assumed to be composed of m (for example, 10) pictures.

  In the process of FIG. 6, first, a GOP code amount is assigned for each GOP (step S51), and the variable k is set to 0 (step S52). The picture allocation code amount for the kth picture is calculated by the picture allocation code amount calculation unit 26 (step S53). Then, it is determined whether or not a scene change has been detected in the immediately preceding picture (k-1th picture) (step S54). If a scene change is detected by the scene change determination unit 29, the calculated picture allocation code amount calculation unit 26 adjusts the picture allocation code amount calculation unit 26 (step S55). The quantization parameter determination unit 30 determines the quantization parameter according to the picture allocation code amount calculated by the picture allocation code amount calculation unit 26 and supplies it to the quantizer 13. Therefore, encoding for the kth picture is performed in the encoding unit 1 (step S56), and the above-described scene change determination process is performed according to the encoding result (step S57). In step S57, scene change determination processing is executed for each of all areas area0-16. Then, 1 is added to the variable k (step S58), and it is determined whether k is larger than m (step S59). If k ≦ m, the process returns to step S53 and the above operation is repeated. If k> m, the processing of the next GOP is started because the processing of 1 GOP is completed.

  When it is executed during the encoding process of one picture, the operation flow is as shown in FIG. In FIG. 7, steps S51 to S55 are the same as those executed every time the encoding process for one picture is completed. If the determination in step S54 is No or after execution of step S55, the variable N = 0 is set (step S61), and the encoding for the area areaN is executed in the encoding unit 1 (step S62). A scene change determination process for the area areaN is executed in accordance with the conversion result (step S63). This scene change determination process corresponds to steps S3 to S8 of the first process and steps S13 to S18 of the second process. It is determined whether or not the scene change determination processing result in step S63 is a scene change detection (step S64). If the scene change is detected, the picture allocation code amount is adjusted by the picture allocation code amount calculation unit 26 (step S65). If it is determined in step S64 that no scene change has been detected, 1 is added to the variable N (step S66), and it is determined whether N is greater than 15 (step S67). If N ≦ 15, the process returns to step S62 and the subsequent operations are repeated. Steps S66 and S67 are executed even after the picture allocation code amount is adjusted in step S65. If N> 15, 1 is added to the variable k in step S58, and it is determined in step S59 whether k is greater than m. If k ≦ m, the process returns to step S53 and the above operation is repeated. If k> m, the processing of the next GOP is started because the processing of 1 GOP is completed.

  Next, adjustment of the picture allocation code amount executed in step S65 will be described.

  When the allocated code amount is smaller than the generated code amount (the generated code amount is large) in the upper part of the picture, the quantization parameter increases in order to keep the generated code amount within the picture allocated code amount, and as shown in FIG. Then, the allocated code amount> the generated code amount. In this case, if the current quantization parameter is calculated from the immediately preceding quantization parameter without performing the scene change determination, the deterioration is conspicuous in the lower part of the picture.

  Therefore, in the first process, when the number of regions where the generated code amount / assigned code amount> threshold value I1 is larger than the threshold value I2, it is determined that the scene change has occurred. In this case, the picture allocation code amount calculation unit 26 adjusts the picture allocation code amount to suppress the increase in accordance with the scene change determination in step S6. Thereby, a sudden change in image quality can be prevented.

Further, when the allocated code amount is smaller than the generated code amount at the upper part of the picture, the quantization parameter increases, and as a result, the generated code amount is suppressed toward the lower part of the picture as shown in FIG. When the ratio> threshold value I1, the threshold value I1 is calculated as shown in Expression (1) with _Inew as Inew.

  For example, when the threshold value I1 = 2.0 and the generated code amount / assigned code amount = 2.0, I1 = 1.0 + (2.0-1.0) /2.0=1 from the equation (1). .5. In the case of the threshold value I1 = 2.0 and the generated code amount / assigned code amount = 1.5, from the equation (1), I1 = 1.0 + (2.0-1.0) /1.5=1.67. It becomes. Thus, the threshold I1 can be set smaller as the ratio increases. Therefore, it is easy to determine that a scene change has occurred, and image quality deterioration can be suppressed.

  On the other hand, if the allocated code amount> the generated code amount (the generated code amount is small) in the upper part of the picture, the quantization parameter becomes small because there is a margin in the generated code amount. As shown in FIG. Code amount <generated code amount. In this case, a large amount of code is generated because the quantization parameter is small even if the image quality can be obtained with a smaller amount of code. Therefore, in the second process, when the region where the generated code amount / assigned code amount <threshold D1 is larger than the threshold D2, it is determined as a scene change, and the picture assigned code amount is set so that the quantization parameter does not become too small. By adjusting, a large amount of code can be assigned to a more complicated picture.

Also, when the allocated code amount> the generated code amount in the upper part of the picture, the quantization parameter becomes smaller. As a result, the generated code amount is controlled to increase toward the lower part of the picture as shown in FIG. When the ratio <threshold value D1, the threshold value D1 is calculated as _Dnew as shown in Expression (2).

  For example, when the threshold value D1 = 0.5 and the generated code amount / assigned code amount = 0.5, D1 = 1.0− (1.0−0.5) × 0.5 = 0.75. When the threshold value D1 = 0.5 and the generated code amount / assigned code amount = 0.1, D1 = 1.0− (1.0−0.5) × 0.1 = 0. 95. Thus, the threshold D1 can be set larger as the ratio is smaller. Therefore, it is easy to determine that a scene change has occurred, and image quality deterioration can be suppressed.

  Further, in the first process, as shown in FIG. 12, when the determination result in step S6 is the number of regions C1 ≦ threshold I2, it is determined that the number of regions C1 is substantially equal to the threshold I2 / 2 (step S21). Yes), the threshold value I1 may be changed as described above in step S22. Similarly, in the second process, as shown in FIG. 13, if the determination result in step S16 is the number of areas C2 ≦ threshold D2, it is determined that the number of areas C2 is substantially equal to the threshold D2 / 2 (step In step S23, the threshold value D1 may be changed as described above.

  Further, the first process and the second process may be executed as shown in FIGS. In the first process of FIG. 14, if the determination result in step S4 is ratio> threshold I1, the number of regions C1 is increased by 1 (step S5), and if ratio ≦ threshold I1, the number of regions C1 is made equal to zero. (Step S5a). After execution of step S5 or S5a, it is determined whether or not the number of areas C1 is larger than a threshold value I3 (sixth threshold value) (step S6a). When the number of areas C1> threshold I3, it is determined that the scene has changed (step S7). That is, a scene change is determined when the ratio> threshold value I1 is detected in each region continuously for the number of times that the threshold value I1 exceeds the threshold value I3.

  In the second process of FIG. 15, if the determination result in step S14 is ratio <threshold D1, the number of areas C2 is increased by 1 (step S15), and if ratio ≧ threshold D1, the number of areas C2 is made equal to zero. (Step S15a). After execution of step S15 or S15a, it is determined whether or not the number of areas C2 is greater than a threshold D3 (seventh threshold) (step S16a). When the number of areas C2> threshold value D3, it is determined that the scene has changed (step S17). That is, a scene change is determined when the ratio <threshold value D1 is detected in each region continuously for the number of times that exceeds the threshold value D3.

  Also in the first process of FIG. 14, as shown in FIG. 16, the threshold value I1 may be changed when it is determined that the number of regions C1 is substantially equal to the threshold value I2 / 2. In the second process of FIG. 15, as shown in FIG. 17, the threshold value D1 may be changed when it is determined that the number of areas C2 is substantially equal to the threshold value D2 / 2.

  Note that it is possible to determine a video fade using the scene change determination process described above. As shown in FIG. 18, when a picture having an area detected as a scene change in the scene change determination process continues for the number of times (picture value C3) exceeding a threshold I4 (fifth threshold), it is determined as a fade. For example, a picture such as a fade-in in which video gradually appears or a fade-out in which video gradually disappears.

  As for a method of dividing one picture into a plurality of regions, for example, it may be divided into a plurality of regions (regions surrounded by solid lines) as schematically shown in FIG. In other words, one picture may be divided in the encoding processing order so that the number of macroblocks in each region is constant, and each region does not necessarily have to be a strip having the same width as shown in FIG.

  As described above, according to the present invention, a scene change can be detected with only a small amount of calculation including a ratio calculation, and image data can be appropriately encoded in accordance with the detection of the scene change. .

  The present invention is applicable to products having an image encoding function such as a DVD / HDD recorder. In the present invention, the encoding / conversion operation as shown in the flowcharts of FIGS. 6 and 7 may be performed by the computer executing the encoding program.

It is a block diagram which shows the structure of the moving image encoder by this invention. It is a block diagram which shows the structure of the rate control part in the apparatus of FIG. It is a figure which shows several area | regions area0-area15. It is a flowchart which shows the 1st process of a scene change determination process. It is a flowchart which shows the 2nd process of a scene change determination process. It is a flowchart which shows schematic operation | movement of the moving image encoder in the case of performing a scene change determination process after completion | finish of 1 picture encoding process. It is a flowchart which shows schematic operation | movement of the moving image encoder in the case of performing a scene change determination process during 1 picture encoding process. It is a figure which shows the change of the picture allocation code amount when the amount of generated code is large in the upper part of a picture. It is a figure which shows the production | generation code amount which decreases toward the lower part of a picture when the production | generation code amount is large in the upper part of a picture. It is a figure which shows the change of the picture allocation code amount in case the production | generation code amount is small in the upper part of a picture. It is a figure which shows the production | generation code amount which increases toward the lower part of a picture when the production | generation code amount is small in the upper part of a picture. It is a flowchart which shows the other example of the 1st process of a scene change determination process. It is a flowchart which shows the other example of the 2nd process of a scene change determination process. It is a flowchart which shows the other example of the 1st process of a scene change determination process. It is a flowchart which shows the other example of the 2nd process of a scene change determination process. It is a flowchart which shows the other example of the 1st process of a scene change determination process. It is a flowchart which shows the other example of the 2nd process of a scene change determination process. It is a flowchart which shows a fade determination process. It is a figure which shows the other example of the several area | region formed by dividing | segmenting 1 picture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Encoding part 2 Rate control part 13 Quantizer 14 Variable length encoder 26 Picture allocation code amount calculation part 27 Area allocation code amount calculation part 28 Code amount ratio calculation part 29 Scene change determination part 30 Quantization parameter determination part

Claims (11)

Encoding means for encoding input image data for each macroblock according to a quantization parameter to generate encoded data;
Picture allocation code amount calculation means for calculating an allocation code amount for each picture of the input image data as a picture allocation code amount;
Quantization parameter determining means for determining a quantization parameter for each macroblock according to the picture allocation code amount calculated by the picture allocation code amount calculation means;
A region allocation code amount calculating means for dividing the input image data into a plurality of regions for each picture and calculating an allocation code amount of each of the plurality of regions as a region allocation code amount;
A ratio calculating unit that calculates a ratio between a generated code amount of encoded data generated by the encoding unit and a region allocation code amount for each region;
Scene change determination means for determining a picture of a scene change according to the ratio calculated by the ratio calculation means,
When a scene change picture is determined by the scene change determination means, the picture allocation code amount calculation means adjusts the calculated picture allocation code amount, and the quantization parameter determination means determines the adjusted picture allocation code amount. And determining the quantization parameter for each of the macroblocks according to the method.   The scene change determination means detects when the ratio calculated by the ratio calculation means in one picture = the number of areas where the generated code amount / area allocation code quantity is greater than the first threshold is greater than the second threshold. 2. The moving picture coding apparatus according to claim 1, wherein the one picture is determined as a scene change picture.   The scene change determination means detects when the ratio calculated by the ratio calculation means in one picture = the number of areas where the generated code quantity / area allocation code quantity is smaller than the third threshold is greater than the fourth threshold. 2. The moving picture coding apparatus according to claim 1, wherein the one picture is determined as a scene change picture.   The scene change determination means has a ratio calculated by the ratio calculation means in one picture = a region where the generated code amount / the region allocation code amount is larger than the first threshold and is continuous more than the sixth threshold on the one picture. 2. The moving picture coding apparatus according to claim 1, wherein when the detected area is detected, the one picture is determined to be a scene change picture.   The scene change determination means has a ratio calculated by the ratio calculation means for one picture = a region where the generated code amount / the region allocation code amount is smaller than a third threshold value and continues more than the seventh threshold value on the one picture. 2. The moving picture coding apparatus according to claim 1, wherein when the detected area is detected, the one picture is determined to be a scene change picture.   The scene change determination means has a ratio calculated by the ratio calculation means in one picture = the number of generated codes / the number of areas where the area allocation code quantity is larger than the first threshold is half the number of the second threshold. 3. The moving picture encoding apparatus according to claim 2, wherein the first threshold value is decreased when the value reaches approximately.   The scene change determination unit is configured such that the ratio calculated by the ratio calculation unit in one picture = the number of generated code amounts / the area allocation code amount is half the number of the fourth threshold value. 4. The moving picture encoding apparatus according to claim 3, wherein the third threshold value is increased when substantially reaching the above. Each time the encoding unit performs encoding for one area, the scene change determination unit determines a scene change picture according to the ratio calculated by the ratio calculation unit,
When a scene change picture is determined by the scene change determination means, the picture allocation code amount calculation means adjusts the calculated picture allocation code amount, and the quantization parameter determination means determines the adjusted picture allocation code amount. The moving picture coding apparatus according to claim 1, wherein the quantization parameter for each subsequent macroblock is determined according to.   2. The moving picture coding apparatus according to claim 1, wherein the plurality of areas are areas obtained by dividing one picture so that the number of macroblocks is constant in the coding processing order.   The scene change determination unit determines that the ratio calculated by the ratio calculation unit = the generated code amount / the region allocation code amount is greater than the first threshold value. The moving picture coding apparatus according to claim 1, wherein the moving picture coding apparatus is determined as a picture. An encoding step of encoding input image data for each macroblock according to a quantization parameter to generate encoded data;
A picture allocation code amount calculating step for calculating an allocation code amount for each picture of the input image data as a picture allocation code amount;
A quantization parameter determination step for determining a quantization parameter for each macroblock according to the picture allocation code amount calculated in the picture allocation code amount calculation step;
A region allocation code amount calculation step of dividing the input image data into a plurality of regions for each picture and calculating an allocation code amount of each of the plurality of regions as a region allocation code amount;
A ratio calculating step for calculating, for each region, a ratio between the generated code amount of the encoded data generated in the encoding step and the region allocation code amount;
A scene change determination step for determining a picture of a scene change according to the ratio calculated in the ratio calculation step,
When the scene change picture is determined in the scene change determination step, the picture allocation code amount calculation step adjusts the calculated picture allocation code amount, and the quantization parameter determination means adjusts the adjusted picture allocation code. A moving picture encoding method, wherein the quantization parameter for each macroblock is determined according to a quantity.