JP2000102003A - Moving picture coding apparatus and moving picture coding method - Google Patents

Abstract

(57) [Summary] [Problem] To realize high-performance and high-quality coding even when the complexity of an image pattern greatly differs depending on each macroblock in a picture. When encoding is performed on a picture composed of a plurality of regions, a target code amount determination unit uses a coding process information for each region of the picture to encode a target code for each region of the picture. Determine the amount. Each unit encoding unit 11 provided corresponding to each region performs encoding processing of each region of the picture according to the target code amount determined by the target code amount determination unit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture coding apparatus and a moving picture coding method, and more particularly to a high-performance moving picture coding apparatus which determines a target code amount for each part of a picture to be coded. The present invention relates to a moving image encoding technique for realizing encoding.

[0002]

2. Description of the Related Art In a conventional code amount control method shown in a test model 5 of MPEG2, the code amount is controlled in the following procedure. A picture described below is a processing unit corresponding to a frame or a field. A macro block is a processing unit that is composed of 16 × 16 pixels and is the minimum unit of code amount control.

(1) For example, an I picture processed before,
The picture complexity index of each picture type such as P picture and B picture, and available GOP (Group
The target code amount of the picture is determined from the remaining code amount in the picture. Here, the complexity index is the product of the picture generation code amount and the average quantization parameter.

(2) Encoding of each macroblock proceeds in raster order from upper left to lower right in a picture.
At this time, the quantization parameter (or quantization step) of the DCT coefficient of the macro block is determined by a value corresponding to the difference between the generated code amount from the first macro block of the picture to the macro block and the target code amount. It is determined. If the difference is large, the quantization step is determined to be a large value, and the generated code amount becomes small. Conversely, if the difference is small, the quantization step is determined to be small, and the generated code amount becomes large, and as a result, the generated code amount of the macroblock concerned Is controlled. Here, the target value from the first macroblock to the macroblock is obtained by dividing the target generated code amount of the picture by the total number of macroblocks of the picture and multiplying by the number from the first macroblock of the picture to the macroblock. Things.

[0005]

In the prior art, the quantization parameter of each macroblock in a picture is determined by the amount of code generated from the first macroblock processed in the picture to the processing of the macroblock and the amount of code generated. This is determined based on the magnitude of the difference from the target value calculated from the target code amount of the picture. The target value is a value obtained by dividing the target generated code amount of the picture by the total number of macroblocks of the picture and multiplying the number from the first macroblock of the picture to the macroblock being processed. Therefore, when the property of a pattern to be subjected to DCT (discrete cosine transform) is largely uneven in a picture, it may be difficult to determine a quantization parameter according to the unevenness. Therefore, there are places where the generated code amount is larger than necessary and places where the generated code amount is smaller, and there is a tendency that the image quality is deteriorated more in parts where the generated code amount is small than in other parts.

Further, in the conventional technique, it is assumed that macroblocks in a picture are coded in raster order. Therefore, when a plurality of parts of a picture are coded in parallel, the above coding is performed. The control method could not be applied.

In view of the above, the present invention firstly discloses that, in the prior art, when the complexity of an image pattern to be subjected to DCT greatly differs depending on each macroblock in a picture, a quantum corresponding to the bias is used. Because it is difficult to determine the optimization parameter, there are places where the generated code amount is larger than necessary and where it is smaller, and there is a tendency that the image quality deteriorates more in the portion where the generated code amount is smaller than in other portions. The purpose is to solve the problem.

Further, since the present invention is premised on encoding macroblocks in a picture in raster order in the past, when encoding a plurality of portions of a picture in parallel, it is necessary to first encode the macroblock in the picture. Coding control method using a quantization parameter determined based on a difference between a code amount generated from a macro block to be processed to processing of the macro block and a target value calculated from a target code amount of the picture The purpose is to solve the problem that is not applicable.

[0009]

In the present invention, the coding information of each part of a picture is tabulated every time the picture coding processing is completed, and an appropriate target code amount of each part is calculated based on the information. In order to determine an appropriate target code amount, specifically, the generated code amount of each part and information on the average quantization parameter are totaled, an index indicating the complexity of each part is obtained from the product, and the ratio is calculated. The target code amount is calculated based on Each unit encoder encodes each part simultaneously based on the target code amount.

[0010] Further, when using such means,
If multiple unit encoders encode each part of a picture in parallel, or if only a single encoding device performs encoding control processing for each part, multiple unit encoders will have unified control In which a plurality of image sequences are encoded.

By the means described above, the present invention has an operational effect that it is possible to realize encoding control that enables encoding with higher image quality in encoding systems having various configurations.

That is, according to the present invention, the code amount reflecting the past characteristics of each part to be coded is assigned to each part as a target value for each picture processing. Is more appropriate than the prior art, and good image quality can be obtained. Specifically, each time the picture coding is started, an appropriate target code amount for each of a plurality of regions set in the picture is determined from information for each region of the past picture, and the code amount control is performed for each region based on the information. , It is possible to realize higher quality encoding. Here, a part for setting the target code amount of each area is newly required, but the code amount control method in each area does not need to be newly changed, and implementation is relatively easy.

After the target code amount is given to each of the coding units at the time of starting the coding process of the picture, each of the coding processing units can perform the processing independently. An encoding device in which the unit encoding unit encodes in parallel
The method can also be applied. This makes it possible to appropriately control the code amount of an encoding system having a plurality of encoding subjects.

Specifically, when it is necessary to divide a picture and perform encoding by a plurality of encoding units due to mounting problems such as a large amount of processing, the above-described encoding control method is used. This makes it possible to realize an image quality equal to or higher than the case where all are encoded by a single encoding unit. In addition, by using the above method, it is possible to perform unified rate control for a plurality of image sequences.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows an example of the configuration of a moving picture coding apparatus according to a first embodiment. This moving picture coding apparatus includes an input picture dividing unit 1
0, a plurality of unit encoders 11, a target code amount determiner 12,
It comprises a stream reconstruction unit 13. Here, as the encoding method, an encoding method capable of controlling the code amount in block units, specifically, MPEG1, MPEG2 or H.264. A code corresponding to an international standard encoding method such as 26x is used.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 1 will be described with reference to the flowchart of FIG.

First, in the input image dividing unit 10, each picture of the input image sequence 14 is divided into a plurality of divided images 1
5 (S10). In this case, it is assumed that each picture is divided so as not to span a macroblock. The division method may be arbitrary as long as it does not cross macroblocks. Each divided image 15 is distributed to each corresponding unit encoding unit 11, and is encoded in each unit encoding unit 11 (S11).

The following steps S12 to S13 are executed in parallel in each unit encoding unit 11. Each unit encoding unit 11 encodes each picture after the target code amount 16 of the picture of each divided image sequence to be processed is given from the target code amount determination unit 12. That is, each unit encoding unit 11 encodes each macro block of the picture while controlling the code amount so that the generated code amount of the assigned picture matches the target code amount 16 (S12). More specifically, each macroblock is encoded by the encoding control method for each macroblock of the MPEG2 test model 5.

Each of the unit encoding units 11 sends information such as a variance value of a motion compensation prediction error (a variance value of an input image in the case of an encoding mode in which no motion compensation is performed) at the end of picture encoding. 12 (S13). Each stream 18 output from each unit encoding unit 11 is reconstructed into one stream 19 by the stream reconstructing unit 13 (S14).

The target code amount determining section 12 operates as follows. This will be described with reference to the flowchart shown in FIG.

The prediction error variance of the entire picture is obtained from the sum of the prediction error variances output from each unit encoder 11 (S15). Next, from the prediction error variance value of the entire picture of the past picture and the remaining code amount of the GOP (Group Of Picture) being processed, the target code amount of the entire picture of the picture to be processed is calculated (S16). The product of the ratio of the variance value of the prediction error of a certain unit encoding unit 11 to the sum of the variance values of the prediction error and the above-mentioned target code amount of the entire picture is defined as the target code amount 16 of the unit encoding unit 11 (S
17). Thus, each unit encoding unit 11
Is determined, and then transmitted to each unit encoding unit 11 as a target code amount 16 of the picture to be processed by each unit encoding unit 11 (S18).

In the above description, the prediction error variance of a picture is obtained from a past picture. When the motion compensation of the picture being processed is completed, the prediction error variance is obtained.
It is also possible to total the information at that time and to quantize the DCT coefficients in each unit encoding unit 11 based on the information, that is, control the code amount.

By using the distribution of the prediction error variance value as in this embodiment, it is possible to set a larger target code amount in an area requiring a larger code amount, and to set an appropriate code amount. An allocation can be made. In addition, this method can distribute the code amount in picture units among the encoding units even in a system having a structure in which a plurality of encoding units encode each region of a picture in parallel. In an encoding system having a plurality of encoding units, encoding with higher image quality than before can be performed. In addition, the target code amount of each encoding unit is determined in proportion to the ratio of the complexity index, but the target code amount of each encoding unit is determined in proportion to the ratio of the square root of the complexity index. It is conceivable to set a limit so that the amount of code distributed to each encoding unit does not become a certain value or more.

[Second Embodiment] FIG. 3 shows an example of the configuration of a moving picture coding apparatus according to a second embodiment, in which a plurality of picture sequences are multiplexed and transmitted. It represents a chemical system. This moving picture coding apparatus includes a plurality of unit coding units 20, a target code amount determination unit 21, and a multiplexing unit (MUX) corresponding to a plurality of input image sequences 23.
Unit) 22.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 2 will be described with reference to the flowchart of FIG.

The pictures in each image sequence 23 are input to each corresponding unit encoding unit 20 (S2
0), and are encoded as follows in each unit encoding unit 20. At this time, each unit encoding unit 20 encodes the picture after receiving the picture target code amount 24 of the picture to be processed from the target code amount determination unit 21.

Each unit encoder 20 encodes each macroblock of the picture while controlling the code amount so that the generated code amount of the picture to be encoded matches the given target code amount 24 ( S21). Each unit encoding unit 20
Transmits the information such as the variance value of the motion compensation prediction error to the target code amount determination unit 21 when the picture encoding is completed (S22). However, in the case of the encoding processing mode in which no motion compensation is performed, the variance value of the input image is used. Each bit stream 26 output from each unit encoder 20 is a MUX
The data is integrated into one bit stream 27 by the unit 22 (S23).

The target code amount determining section 21 operates as follows. This will be described according to the flowchart shown in FIG.

From the sum of the prediction error variance values (or input signal variance values) 25 output from each unit encoding unit 20, the variance value of the prediction error of the picture of the entire image sequence (hereinafter referred to as the prediction error variance value of all pictures) ) Is obtained (S24). From the variance value of the prediction error of the entire screen of each past picture type and the remaining code amount of the GOP (Group Of Picture) being processed, the target code amount of all the pictures to be processed is calculated (S25).

Next, the sum of the variance of the prediction error of each unit coding unit 20 and the variance of the prediction error of each unit coding unit 20 are calculated at the same time (S26). The product of the ratio of the variance value of the prediction error of a certain unit encoding unit 20 to the sum of the variance values of the calculated prediction errors and the above-described target code amount of all the pictures is defined as the target code amount 24 of the picture of each image sequence 23.
In this way, the target code amount 24 of the picture of each unit coding unit 20 is determined, and is given to each unit coding unit 20 as the target code amount of the picture to be processed by the unit coding unit 20 (S27). ).

In the above description, the prediction error variance of a picture is obtained from a past picture. When the motion compensation of the picture being processed is completed, the prediction error variance is obtained.
It is also possible to sum up the information at that time and to quantize the DCT coefficients, that is, control the code amount in each unit encoding unit 20 based on the information.

In this embodiment, the rate of the target code amount to be assigned to each image sequence is determined from the complexity of the pictures of the plurality of image sequences, so that unified rate control for each picture of the plurality of image sequences is performed. To achieve. It is possible to set a larger target code amount for sequences that require more code amount within a limited bit rate, realizing high-quality encoding of each image sequence within a limited bit rate. can do.

[Third Embodiment] FIG. 5 shows an example of the configuration of a moving picture coding apparatus according to a third embodiment.
This moving picture coding apparatus includes an input picture dividing section 30, a plurality of unit coding sections 31, a target code amount determining section 32, and a stream reconstructing section 33. Here, as an encoding method, an encoding method capable of controlling the code amount in block units, specifically, MPEG1, MPEG2, or H.264. A method corresponding to an international standard encoding method such as 26x is used.

The overall operation of the moving picture coding apparatus shown in FIG. 5 will be described below with reference to the flowchart of FIG.

First, in the input image dividing unit 30, each picture of the input image sequence 34 is divided into a plurality of divided images 3
5 (S30). In this case, it is assumed that each picture is divided so as not to span a macroblock. The sequence of each divided image 35 is distributed to each corresponding unit encoding unit 31 (S31), and is encoded in each unit encoding unit 31.

The following steps S32 to S33 are executed in parallel in each unit encoding unit 31. After receiving the target code amount 36 of the picture of each divided image sequence to be processed from the target code amount determination unit 32, each unit encoding unit 31 performs encoding of each picture as follows. Each unit encoding unit 31 encodes each macro block of the picture while controlling the code amount so that the generated code amount of the assigned picture matches the target code amount 35 (S32). Repeat this macroblock coding,
When the picture encoding is completed, each unit encoding unit 31
Information such as the generated code amount and the average quantization parameter 37 is transmitted to the target code amount determination unit 32 (S33). Each stream 38 output from each unit encoding unit 31 is reconstructed into one stream 39 by the stream reconstructing unit 33 (S34).

The target code amount determining section 32 operates as follows. This will be described according to the flowchart shown in FIG.

The generated code amount of the entire picture is obtained from the sum of the generated code amounts output from each unit coding unit 31 (S3).
5). Next, the average quantization parameter of the entire picture is obtained from the ratio between the average quantization parameter output from each unit encoding unit 31 and the size of each divided image (S36). The complexity index of the entire picture is obtained by taking the product of the generated code amount of the entire picture and the average quantization parameter of the entire picture described above (S37). Then, the complexity index of the entire picture of the past picture and the GOP (Group Of
The target code amount of the entire picture to be processed is calculated from the remaining code amount of Picture (S38). Next, the product of the picture generation code amount output by the unit encoding unit 31 and the average quantization parameter is calculated as a complexity index of the picture processed by each unit encoding unit 31, and at the same time, the complexity of each unit encoding unit 31 is calculated. The sum of the index is calculated (S39). The product of the ratio of the complexity index of a certain unit encoding unit 31 to the sum of the above-mentioned complexity indices and the above-described target code amount of the entire picture is defined as the target code amount 36 of the picture processed by the unit encoding unit 31 ( S40). In this manner, the target code amount 36 of the picture to be processed by each unit coding unit 31 is determined, and then the target code amount when each unit coding unit 31 processes the picture is set as the target code amount. 31 (S41).

In this embodiment, the product of the generated code amount and the average quantization parameter is used for the distribution of the code amount as an index indicating the complexity of each area. Quantization tends to be constant regardless of whether quantization is performed. By allocating the code amount based on the ratio of this index, the degree of quantization in each region is almost averaged, and the average of the entire screen is averaged. This is effective for improving image quality.

In this embodiment, the product of the generated code amount and the average quantization parameter is used. However, the complexity is calculated by a value obtained by taking the product by raising each parameter to the power or a sum of such values. It is also effective to use the index as a representative. It is also effective to take measures to limit the distribution, for example, when the distribution becomes extremely small, instead of the distribution of the code amount in proportion to the index.

According to the above-described method, in a system having a structure in which a plurality of encoding units perform encoding in parallel as described in this embodiment, an appropriate code amount for each picture between the encoding units is used. Distribution is possible, which contributes to improvement of image quality.

[Fourth Embodiment] FIG. 7 shows an example of the configuration of a moving picture coding apparatus according to a fourth embodiment, in which a plurality of picture sequences are multiplexed and transmitted. It represents a chemical system. This moving picture coding apparatus includes a plurality of unit coding units 40 corresponding to a plurality of input image sequences 43, a target code amount determining unit 41, and a multiplexing unit (MUX).
Unit) 42.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 7 will be described with reference to the flowchart of FIG.

The pictures in each image sequence 43 are input to each corresponding unit encoding unit 40 (S5).
0), and are encoded in each unit encoding section 40 as follows. At this time, each unit encoding unit 40 encodes the picture after receiving the picture target code amount 44 of the picture to be processed from the target code amount determination unit 41.

Each unit encoding section 40 encodes each macroblock of the picture while controlling the code amount so that the generated code amount of the picture to be encoded matches the given target code amount 44 ( S51). When coding of each macro block is repeated and picture coding is completed, each unit coding unit 40 transmits information such as a generated code amount and an average quantization parameter 45 to the target code amount determination unit 41 (S
52). Each bit stream 46 output from each unit encoding unit 40 is integrated into one bit stream 47 in the MUX unit 42 (S53).

The target code amount determining section 41 operates as follows. This will be described according to the flowchart shown in FIG.

From the sum of the generated code amounts output from each unit coding unit 40, the generated code amount of the pictures of the entire image sequence (hereinafter referred to as the generated code amount of all the pictures) is obtained (S
54). Next, the average quantization parameter of the pictures of the entire image sequence (hereinafter, referred to as the average quantization parameter of all the pictures) is obtained from the ratio between the average quantization parameter output from each unit encoding unit 40 and the size of each picture. (S
55).

The complexity index of all pictures is obtained by multiplying the above-mentioned generated code amount of all pictures by the average quantization parameter of all pictures (S56). Then, the complexity of all the past pictures is used as an index and the GO being processed.
From the total sum of the remaining code amounts of P (Group Of Picture), the target code amounts of all the pictures to be processed are calculated (S
57). Next, a complexity index is obtained from the product of the generated code amount of each unit encoding unit 40 and the average quantization parameter, and at the same time, the sum of the complexity index of each unit encoding unit 40 is calculated (S5).
8).

The product of the ratio of the complexity index of a certain unit encoding unit 40 to the sum of the above-mentioned complexity indices and the above-mentioned target code amount of all pictures is defined as the picture target code amount 44 of each image sequence 43 ( S59). In this way, the target code amount 44 of the picture of each unit
Is determined, and given to each unit encoding unit 40 as a target code amount of a picture to be processed by each unit encoding unit 40 (S
60).

According to this embodiment, unified rate control in a picture unit of a plurality of image sequences becomes possible. In particular, the product of the generated code amount and the average quantization parameter is used to distribute the code amount as an index indicating the complexity, but this index is constant regardless of the type of quantization performed for the same image pattern. , And more appropriate code amount distribution becomes possible.

[Fifth Embodiment] FIG. 9 shows an example of the configuration of a moving picture coding apparatus according to a fifth embodiment.
This moving picture coding apparatus includes an input picture dividing section 50, a plurality of unit coding sections 51, a target code amount determining section 52, and a stream reconstructing section 53. Here, as an encoding method, an encoding method capable of controlling the code amount in block units, specifically, MPEG1, MPEG2 or H.264. 26
A method corresponding to an international standard encoding method such as x is used.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 9 will be described with reference to the flowchart of FIG.

First, in the input image dividing section 50, each picture of the input image sequence 54 is divided into a plurality of divided images 5
5 (S70). In this case, it is assumed that each picture is divided so as not to span a macroblock. The sequence of each divided image 55 is distributed to each corresponding unit encoding unit 51 (S71),
Through the following steps S72 to S73, the encoding is performed in parallel in each unit encoding unit 51.

Each unit encoding section 51 encodes each picture after the target code quantity 56 of the picture of each divided image sequence to be processed is given from the target code quantity determining section 52. Each unit encoding unit 51 encodes each macroblock of the divided image picture while controlling the code amount so that the generated code amount of the assigned divided image picture matches the target code amount 56 (S72). When the encoding of the divided image picture is completed, each unit encoding unit 51
Information such as the generated code amount and the average quantization parameter 57 is transmitted to the target code amount determination unit 52 (S73). Each stream 58 output from each unit encoding unit 51 is reconstructed into one stream 59 by the stream reconstructing unit 53 (S74).

The target code amount determining section 52 operates as follows. This will be described with reference to the flowchart shown in FIG.

The generated code amount of the entire picture is obtained from the sum of the generated code amounts output from the unit coding units 51 (S7).
5). Further, the average quantization parameter of the entire picture is obtained from the ratio between the average quantization parameter output from each unit encoding unit 51 and the size of each divided image (S76). By calculating the product of the generated code amount of the entire picture and the average quantization parameter of the entire picture described above, a complexity index of the entire picture is obtained (S77). Then, the past complexity index of each picture type in the past and the GO being processed
From the remaining code amount of P (Group Of Picture), the target code amount of the entire picture to be processed is calculated (S7).
8).

Next, as the complexity index of each unit encoding unit 51, the product of the picture generation code amount output from each unit encoding unit 51 and the average quantization parameter is calculated. The sum of the complexity indices is calculated (S7)
9). The product of the ratio of the complexity index of a certain unit encoding unit 51 to the sum of the complexity indices and the above-described target code amount of the entire picture is calculated as the target code amount 56 of the unit encoding unit 51.
(S80). In this way, the target code amount 56 of the picture of each unit encoding unit 51 is determined, and each unit code unit 51 is used as a target code amount when processing a picture of the same picture type. (S81).

In this embodiment, the past pictures used for code amount distribution are limited to pictures having the same picture type as the picture type. Therefore, the code amount can be distributed in consideration of the influence of the difference in the DCT target image pattern in the picture type. Therefore, in a system having a structure in which a plurality of encoding units perform encoding in parallel, it is possible to appropriately distribute the code amount in units of pictures between the encoding units, thereby contributing to an improvement in image quality.

[Sixth Embodiment] FIG. 11 shows an example of the configuration of a moving picture coding apparatus according to the sixth embodiment. In the above-described embodiment, the divided images are encoded in parallel by the plurality of unit encoding units. However, in the present embodiment, each divided image is encoded in one encoding unit by time division. This moving picture coding apparatus includes an input picture dividing unit 6
0, an encoding unit 61, a target code amount determination unit 62, and a stream reconstruction unit 63. Here, as an encoding method, an encoding method capable of controlling the code amount in block units, specifically, MPEG1, MPEG2 or H.264. 26
A method corresponding to an international standard encoding method such as x is used.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 11 will be described with reference to the flowchart of FIG.

First, in the input image dividing section 60, each picture of the input image sequence 64 is divided into a plurality of divided images 6
5 (S90). In this case, it is assumed that each picture is divided so as not to span a macroblock. The pictures of each of the divided images 65 are sequentially sent to the encoding unit 61 (S91), and are encoded by the encoding unit 61. However, there is only one entity that implements the encoding unit 61, and the pictures of each image sequence are time-divisionally and temporally serially encoded. In addition, the encoding unit 61 has a storage medium necessary for performing inter-frame encoding of a plurality of sequences.

The encoding unit 61 encodes each picture after receiving the target code amount 66 of the picture of the divided image sequence to be processed from the target code amount determination unit 62. The encoding unit 61 encodes each macroblock of the divided image picture while controlling the code amount so that the generated code amount of the divided image picture to be encoded matches the target code amount 66 (S92). .

When the encoding of each divided picture is completed, the encoding unit 61 transmits information such as the generated code amount and the average quantization parameter 67 to the target code amount determination unit 62 (S93). The above steps S91 to S93 are repeated until the processing for all divided images is completed. Encoding unit 6
Stream 6 of each divided image sequence output from 1
8 is reconstructed into one stream 69 by the stream reconstruction unit 63 (S94).

The target code amount determining section 62 operates as follows. This will be described according to the flowchart shown in FIG.

The generated code amount of the entire picture is obtained from the sum of the generated code amounts of the divided images output by the coding unit 61 (S95). Further, the average quantization parameter of the entire picture is obtained from the ratio between the average quantization parameter output from the encoding unit 61 and the size of each divided image (S96). The product of the generated code amount of the entire picture and the average quantization parameter of the entire picture as described above obtains the complexity index of the entire picture (S97). Then, the complexity index of the entire picture of the past picture and the GOP (Group Of
The target code amount of the entire picture to be processed is calculated from the remaining code amount of Picture (S98).

Next, the product of the picture generation code amount output by the encoding unit 61 and the average quantization parameter as the complexity index of each divided image is calculated, and at the same time, the sum of the complexity index of the encoding unit 61 is calculated. (S99). The product of the ratio of the complexity index of a certain divided image to the sum of the complexity indices and the target code amount of the entire picture is set as the target code amount 66 of the divided image (S100). In this way, the target code amount 66 of the picture of each divided image is determined, and then given to the encoding unit 61 as the target code amount when the encoding unit 61 processes the divided image picture of the same picture type. (S101).

In this embodiment, past pictures used for code amount distribution are limited to pictures having the same picture type as the picture type. Therefore, the code amount can be distributed in consideration of the influence of the difference in the image pattern of the DCT target in the picture type, and the image quality is improved.

[Seventh Embodiment] FIG. 13 shows an example of the configuration of a moving picture coding apparatus according to a seventh embodiment. In this moving picture coding apparatus, a plurality of regions are set in a processed image, and only a process of controlling a generated code amount is separately performed for each region. Further, in this example, as an encoding method, an encoding method capable of controlling the amount of code in units of processing blocks, specifically, MPEG1, MPEG2, or H.264. A method corresponding to an international standard encoding method such as 26x is used. Therefore, in this case, the quantization unit 72 that determines the quantization parameter of the DCT coefficient is applied as the generated code amount control unit.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 13 will be described with reference to the flowchart of FIG.

The motion compensating section 70 determines whether the input image sequence 7
5 is subjected to motion compensation (S110), and the resulting prediction error image 76 is sent to the DCT unit 71. DCT unit 71
Calculates a DCT coefficient 77, and calculates a quantization unit 72 for each region.
(S111). When starting the determination of the quantization parameter of the macroblock in each region of the picture, each quantization unit 72 starts after receiving the target code amount 78 of each region from the target code amount determination unit 73. However, there are a plurality of quantization units 72, which operate in parallel.

Each quantizing unit 72 controls the code amount so that the generated code amount of each region matches the target code amount 78 of each region given from the target code amount determination unit 73, and The quantization parameter of each macroblock is determined (S112). When the determination of the quantization parameter of the region is completed, each quantization unit 72 transmits the generated code amount and the average quantization parameter 79 of the region to the target code amount determination unit 73 (S113). The variable length coding unit 74 performs variable length coding according to the determined quantization parameter (S11).
4).

The target code amount determining section 73 operates as follows. This will be described according to the flowchart shown in FIG.

The target code amount determination section 73 obtains the generated code amount of the entire picture from the sum of the generated code amounts of the respective areas (S
115). Next, the target code amount determination unit 73 obtains an average quantization parameter of the entire picture from the average quantization parameter of each area and the size of each area (S116). next,
As the complexity index of the entire screen, the product of the above-described generated code amount of the entire picture and the average quantization parameter of the entire picture is obtained (S117). Then, the complexity index of the entire screen of each past picture type and the GO being processed
From the remaining code amount of P (Group Of Picture), the target code amount of the entire picture to be processed is calculated (S11).
8).

Next, as the complexity index of each area, the product of the generated code amount output by the area and the average quantization parameter is calculated, and at the same time, the sum of the complexity index of each area is calculated (S1).
19). The product of the ratio of the index indicating the complexity of a certain region to the sum of the complexity indicators and the above-described target code amount of the entire picture is set as the target code amount of the region (S120). In this way, the target code amount 78 of each area is determined, and is given to the quantization unit 72 in charge of each area as the target code amount of each area when processing the same picture type next (S121).

According to this embodiment, the code amount reflecting the past characteristics of each part to be coded is assigned to each part as a target value for each picture processing. More appropriate than technology,
Good image quality can be obtained. Specifically, an appropriate target code amount for each of a plurality of regions set in the picture at each start of picture coding is determined from information of each region of a past picture, and the code amount is controlled for each region based on the determined target code amount. This makes it possible to realize higher quality encoding.

[Eighth Embodiment] FIG. 15 shows an example of the configuration of a moving picture coding apparatus according to the eighth embodiment. In the above-described embodiment, the quantization is performed in parallel by the plurality of quantization units.
The coefficients are processed serially in time by a single quantizer 82 in a time-division manner. In the moving picture coding apparatus shown in FIG. 15, a plurality of regions are set in a processed image, and only the process of controlling the generated code amount is separately performed for each region. Further, in this example, as an encoding method, an encoding method capable of controlling the amount of code in units of processing blocks, specifically, MPEG1, MPEG2, or H.264. 2
A method corresponding to an international standard encoding method such as 6x is used. Therefore, in this case, the DCT is used as the generated code amount control unit.
This applies to the quantization unit 82 that determines the quantization parameter of the coefficient.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 15 will be described with reference to the flowchart of FIG.

The motion compensating section 80 determines whether the input image sequence 8
5 is subjected to motion compensation (S130), and the resulting prediction error image 86 is sent to the DCT unit 81. DCT unit 81
Calculates the DCT coefficient 87 (S131), and
Send to When starting the determination of the quantization parameter of the macroblock in each area of the picture, each quantization unit 82
The processing is started after the target code amount 88 of each area is given from the target code amount determination unit 83. However, there is only one entity that implements the quantization unit 82, and the quantization of each area is performed in a time-division and time-series manner by the processing described below.

The quantization unit 82 controls the code amount such that the generated coding amount of each region matches the target code amount 88 of each region given from the target code amount determination unit 83, and The quantization parameter of each macroblock is determined (S132). When the determination of the quantization parameter of each region is completed, the quantization unit 82 transmits the generated code amount and the average quantization parameter 89 of the region to the target code amount determination unit 83 (S133). The above steps S132 to S133
Is repeated until the processing for all areas is completed. The variable length coding unit 84 performs variable length coding according to the quantization parameter determined by the quantization unit 82 (S13).
4).

The target code amount determining section 83 operates as follows. This will be described with reference to the flowchart shown in FIG.

The target code amount determining section 83 obtains the generated code amount of the entire picture from the sum of the generated code amounts of the respective areas (S
135). An average quantization parameter of the entire picture is obtained from the average quantization parameter of each area and the size of each area (S136). Next, the product of the above-described generated code amount of the entire picture and the average quantization parameter of the entire picture is calculated as a complexity index of the entire screen (S137). Then, the target code amount of the entire picture to be processed is calculated from the complexity index of the entire screen of each past picture type and the remaining code amount of the GOP (Group Of Picture) being processed (S138).

Next, the product of the generated code amount output by the region as the complexity index of each region and the average quantization parameter is calculated, and at the same time, the sum of the complexity index of each region is calculated (S1).
39). The product of the ratio of the index representing the complexity of a certain region to the sum of the complexity indicators and the above-described target code amount of the entire picture is set as the target code amount of the region (S140). In this way, the target code amount 89 of each region is determined, and is given to the quantization unit 82 in charge of each region as the target code amount of each region when processing the same picture type next (S141).

According to this embodiment, the code amount is assigned to each portion as a target value by reflecting the past characteristics of each portion to be coded for each picture process, so that the code amount of the entire image is distributed. More appropriate than the prior art,
Good image quality can be obtained. Specifically, an appropriate target code amount for each of a plurality of regions set in the picture at each start of picture coding is determined from information for each region of a past picture, and code amount control is performed for each region based on the information. By doing so, it is possible to realize higher quality encoding.

[Ninth Embodiment] FIG. 17 shows an example of the configuration of a moving picture encoding apparatus according to the ninth embodiment, in which a plurality of picture sequences are multiplexed and transmitted. It represents a chemical system. This video encoding device
A plurality of unit encoders 90 corresponding to a plurality of input image sequences 93, a target code amount determination unit 91, and a multiplexing unit (MUX)
(Unit) 92.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 17 will be described with reference to the flowchart of FIG.

The pictures in each image sequence 93 are input to each corresponding unit encoding section 90 (S15).
0), each unit encoding section 90 performs encoding by the following processing. At this time, each unit encoding unit 90 encodes the picture after receiving the picture target code amount 94 of the picture to be processed from the target code amount determination unit 91.

Each unit encoder 90 encodes each macroblock of the picture while controlling the code amount so that the generated code amount of the picture to be encoded matches the given target code amount 94. (S151). When the picture encoding is completed, each unit encoding unit 90 transmits information such as the generated code amount and the average quantization parameter 95 to the target code amount determining unit 91 (S152). Each bit stream 96 output from each unit encoding unit 90 is integrated into one bit stream 97 in the MUX unit 92 (S1).
53).

The target code amount determining section 91 operates as follows. Description will be made according to the flowchart shown in FIG.

The target code amount determining unit 91 obtains the generated code amount of the picture of the entire image sequence (hereinafter, referred to as the generated code amount of all the pictures) from the total sum of the generated code amounts output from the unit coding units 90 ( S154). Further, an average quantization parameter of the pictures of the entire image sequence (hereinafter referred to as an average quantization parameter of all the pictures) is obtained from the ratio of the average quantization parameter output from each unit encoding unit 90 and the size of each picture (hereinafter, referred to as the average quantization parameter of all the pictures) ( S155). The complexity index of all pictures is obtained by multiplying the generated code amount of all pictures described above and the average quantization parameter of all pictures (S156). Then, the target code amount of all the pictures to be processed is calculated from the complexity index of all the past pictures and the sum of the remaining code amounts of the GOP (Group Of Picture) being processed (S157).

Next, a complexity index is obtained from the product of the generated code amount of each unit encoding unit 90 and the average quantization parameter, and at the same time, the sum of the complexity index of each unit encoding unit 90 is calculated (S158). The product of the ratio of the complexity index of a certain unit encoding unit 90 to the sum of the complexity indexes and the above-mentioned target code amount of all the pictures is set as the picture target code amount 94 of each image sequence 93 (S159). Thus, the target code amount 94 of the picture of each unit encoding unit 90 is obtained.
Is determined, and is given to each unit encoding unit 90 as a target code amount of a picture of the same picture type processed by each unit encoding unit 90 (S160).

According to this embodiment, unified rate control in a picture unit of a plurality of image sequences can be performed. In particular, the product of the generated code amount and the average quantization parameter is used to distribute the code amount as an index indicating the complexity, but this index is constant regardless of the type of quantization performed for the same image pattern. , And more appropriate code amount distribution becomes possible. In addition, the bias of the complexity of the image depending on the picture type can be processed without any problem by performing the code amount distribution determination processing for each picture type.

[Tenth Embodiment] FIG. 19 shows a tenth embodiment.
1 shows a configuration example of a video encoding device according to an embodiment of the present invention. This moving picture encoding apparatus encodes a plurality of video object sequences already created in the preceding stage under unified rate control. As a specific encoding method, MPEG4 is used. Used.

Hereinafter, the overall operation of the moving picture coding apparatus shown in FIG. 19 will be described with reference to the flowchart of FIG.

A video object plane in each video object sequence 104 (hereinafter referred to as VOP)
Is input to each corresponding unit encoding unit 101 (S170), and is encoded in each unit encoding unit 101. Also, the VO in the video object referred to here
P corresponds to a picture in a normal image sequence.

At this time, each unit coding section 101 performs VOP coding after being provided with a target code amount 105 of a VOP to be processed from the target code amount determination section 102. Each unit encoding unit 101 controls the code amount such that the generated code amount of the VOP to be encoded matches the target code amount 105 given from the target code amount determination unit 102,
Encode each macroblock of the VOP (S17)
1). When the VOP encoding is completed, each unit encoding unit 1
01 transmits information such as the generated code amount and the average quantization parameter 106 to the target code amount determination unit 102 (S17).
2). Each bit stream 107 output from each unit encoding unit 101 is integrated into one bit stream 108 in the MUX unit 103 (S173).

The target code amount determining section 102 operates as follows. Description will be made according to the flowchart shown in FIG.

The target code amount determination unit 102 obtains the generated code amount of the VOPs of all object sequences (hereinafter, referred to as the generated code amount of all VOPs) from the total sum of the generated code amounts output from each unit encoding unit 101 (hereinafter, referred to as the generated code amount of all VOPs). S174). Further, an average quantization parameter of VOPs of all object sequences (hereinafter, referred to as an average quantization parameter of all VOPs) is obtained from a ratio of the average quantization parameter output from each unit encoding unit 101 and the size of each VOP (hereinafter, referred to as an average quantization parameter of all VOPs). S175). The complexity index of all VOPs is obtained by multiplying the amount of generated codes of all VOPs and the average quantization parameter of all VOPs described above (S176). Then, the target code amount of all VOPs to be processed is calculated from the complexity index of all VOPs in the past VOP and the sum of the remaining available code amounts (S17).
7).

Next, a complexity index is obtained from the product of the generated code amount of each unit encoding unit 101 and the average quantization parameter, and at the same time, the sum of the complexity index of each unit encoding unit 101 is calculated (S178). The ratio of the complexity index of a certain unit encoding unit 101 to the sum of the complexity indexes and the above-mentioned total VOP
Of the VOP of each video object sequence 104 with respect to each unit encoding unit 101 (S179). In this manner, the target code amount 10 of the VOP of each unit coding unit 101 is obtained.
5 is given, and given to each unit encoding unit 101 as a target code amount of a VOP of the same encoding type processed by each unit encoding unit 101 (S180).

According to this embodiment, unified rate control of a plurality of video object sequences on a VOP basis is possible. In particular, the product of the generated code amount and the average quantization parameter is used to distribute the code amount as an index indicating the complexity, but this index is constant regardless of the type of quantization performed for the same image pattern. , And more appropriate code amount distribution becomes possible.

[0100]

As described above, according to the present invention, it is possible to obtain an effect that high-quality coding can be performed in coding a moving image. In particular, in the encoding of a moving image including a plurality of encoding devices, an effect that high-performance and high-quality encoding can be performed is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video encoding device according to a first embodiment.

FIG. 2 is a flowchart illustrating an operation of the video encoding device according to the first embodiment.

FIG. 3 is a configuration diagram of a video encoding device according to a second embodiment.

FIG. 4 is a flowchart illustrating an operation of the video encoding device according to the second embodiment.

FIG. 5 is a configuration diagram of a video encoding device according to a third embodiment.

FIG. 6 is a flowchart illustrating an operation of the video encoding device according to the third embodiment.

FIG. 7 is a configuration diagram of a video encoding device according to a fourth embodiment.

FIG. 8 is a flowchart illustrating an operation of the video encoding device according to the fourth embodiment.

FIG. 9 is a configuration diagram of a video encoding device according to a fifth embodiment.

FIG. 10 is a flowchart illustrating an operation of the video encoding device according to the fifth embodiment.

FIG. 11 is a configuration diagram of a video encoding device according to a sixth embodiment.

FIG. 12 is a flowchart illustrating an operation of the video encoding device according to the sixth embodiment.

FIG. 13 is a configuration diagram of a video encoding device according to a seventh embodiment.

FIG. 14 is a flowchart illustrating an operation of the video encoding device according to the seventh embodiment.

FIG. 15 is a configuration diagram of a video encoding device according to an eighth embodiment.

FIG. 16 is a flowchart illustrating an operation of the video encoding device according to the eighth embodiment.

FIG. 17 is a configuration diagram of a video encoding device according to a ninth embodiment.

FIG. 18 is a flowchart illustrating an operation of the video encoding device according to the ninth embodiment.

FIG. 19 is a configuration diagram of a video encoding device according to a tenth embodiment.

FIG. 20 is a flowchart illustrating an operation of the video encoding device according to the tenth embodiment.

[Explanation of symbols]

 Reference Signs List 10 input image division unit 11 unit encoding unit 12 target code amount determination unit 13 stream reconstruction unit 14 input image sequence 15 divided image 16 target code amount 17 prediction error variance value / input signal variance value 18 stream 19 stream

[Procedure amendment]

[Submission date] September 27, 1999 (September 9, 1999
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] Further, when using such means,
If the encoding unit a plurality of units for encoding each part of the picture in parallel, etc. When performing only encoding control process in a single coding unit for each moiety.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

Specifically, when it is necessary to divide a picture and perform encoding by a plurality of encoding units due to mounting problems such as a large amount of processing, the above-described encoding control method is used. By doing so, it is possible to achieve an image quality equivalent to or better than the case where all are encoded by a single encoding unit.
You.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

[Second Embodiment Different from the Present Invention] FIG. 3 shows an example of the configuration of a moving picture coding apparatus according to a second embodiment, in which a plurality of picture sequences are multiplexed and transmitted. FIG. This moving picture coding apparatus includes a plurality of unit coding units 20 corresponding to a plurality of input image sequences 23, a target code amount determining unit 21, and a multiplexing unit (MUX unit) 22.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction contents]

[Fourth Embodiment Different from the Present Invention] FIG. 7 shows an example of the configuration of a moving picture coding apparatus according to a fourth embodiment, in which a plurality of picture sequences are multiplexed and transmitted. FIG. This moving picture coding apparatus includes a plurality of unit coding units 40 corresponding to a plurality of input image sequences 43, a target code amount determination unit 41, and a multiplexing unit (MUX unit) 42.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

[Ninth Embodiment Different from the Present Invention] FIG. 17 shows an example of the configuration of a moving picture coding apparatus according to the ninth embodiment, in which a plurality of picture sequences are multiplexed and transmitted. FIG. The moving picture coding apparatus includes a plurality of unit coding units 90 corresponding to a plurality of input image sequences 93, a target code amount determination unit 91,
A multiplexing unit (MUX unit) 92 is provided.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0092

[Correction method] Change

[Correction contents]

[Tenth Embodiment Different from the Present Invention]
FIG. 19 shows a configuration example of a video encoding device according to the tenth embodiment. This video encoding apparatus encodes a plurality of video object sequences already created in the preceding stage under unified rate control. MPEG4 is used as a specific encoding method. Used.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C059 KK23 MA00 MA04 MA05 MA23 MB14 MC11 PP04 RB10 TA46 TA60 TB04 TB07 TB18 TC03 TC10 TC38 UA02

Claims (14)

[Claims] 1. A moving picture coding apparatus for coding a picture comprising a plurality of regions, wherein a target code amount for each region of the picture is calculated by using coding processing information for each region of the picture. And a coding unit for coding each area of the picture in accordance with the target code amount determined by the target code amount determining unit. . 2. A moving picture coding apparatus for coding a plurality of picture sequences synchronously on a picture basis, wherein each picture sequence is encoded by using coding processing information of a picture at the same time of each picture sequence. A target code amount determining unit that determines a target code amount of each picture; and an encoding unit that performs an encoding process of a picture of each image sequence according to the target code amount determined by the target code amount determining unit. A moving picture coding apparatus characterized by the following. 3. The moving picture coding apparatus according to claim 1, wherein the target code amount determining unit uses an index indicating complexity as the coding processing information. Encoding device. 4. The moving picture coding apparatus according to claim 3, wherein the index indicating the complexity used by the target code amount determining unit as coding processing information is represented by a product of an average quantization parameter and a generated code amount. A moving picture coding apparatus characterized in that the moving picture is encoded. 5. A moving picture coding apparatus for coding a picture comprising a plurality of regions, wherein each of the pictures is encoded by using an index indicating complexity as coding processing information for each region of the picture. A target code amount determining unit that determines a target code amount for each region; and an encoding unit that performs an encoding process on each region of the picture according to the target code amount determined by the target code amount determining unit. A moving picture coding apparatus, characterized in that a picture having the same picture type as a picture to be coded is used as a picture for counting coding processing information for calculating an index indicating complexity by a quantity determining unit. 6. A moving picture coding apparatus for coding a plurality of picture sequences synchronously on a picture basis, wherein an index representing complexity is used as coding processing information of a picture at the same time in each picture sequence. A target code amount determining unit for determining a target code amount of a picture for each image sequence;
According to the target code amount determined by the target code amount determination unit,
An encoding unit that performs an encoding process on a picture of each image sequence, wherein the target code amount determining unit aggregates encoding processing information for calculating an index indicating complexity, as intra-frame prediction, frame A moving picture coding apparatus characterized by using a picture having the same picture type as a picture of each picture sequence to be coded when there are a plurality of picture coding types such as inter prediction. 7. The moving picture coding apparatus according to claim 2, further comprising using a video object sequence in object coding as a picture sequence. 8. A moving picture coding method for coding a picture composed of a plurality of regions, wherein a target code amount for each region of the picture is calculated using coding processing information for each region of the picture. And a coding process for each region of the picture according to the determined target code amount. 9. A moving picture coding method for coding a plurality of picture sequences synchronously on a picture basis, wherein each picture sequence is encoded using information on a picture at the same time of each picture sequence. A moving picture coding method comprising: determining a target code amount of each picture; and performing a coding process on the picture of each image sequence according to the determined target code amount. 10. The moving picture coding method according to claim 8, wherein an index indicating complexity is used as coding processing information. 11. A moving picture encoding method according to claim 10, wherein a complexity index represented by a product of an average quantization parameter and a generated code amount is used as an index indicating complexity. Encoding method. 12. A moving picture coding method for coding a picture composed of a plurality of areas, wherein each picture is encoded using an index indicating complexity as coding processing information for each area of the picture. A target code amount for each region is determined, and in accordance with the determined target code amount, encoding processing is performed on each region of the picture, and encoding processing information for calculating an index indicating the complexity is calculated as a picture for counting. A moving picture encoding method using a picture having the same picture type as a picture to be encoded. 13. A moving image encoding method for synchronously encoding a plurality of image sequences in units of pictures, wherein an index representing complexity is used as encoding processing information of pictures at the same time in each image sequence. Then, a target code amount of a picture for each image sequence is determined, a coding process of a picture of each image sequence is performed according to the determined target code amount, and coding for calculating the index indicating the complexity is performed. When a plurality of picture coding types such as intra-frame prediction and inter-frame prediction are present, a picture having the same picture type as the picture of each image sequence to be coded is used as the picture for which the processing information is totaled. Moving image encoding method. 14. The moving picture coding method according to claim 9, further comprising using a video object sequence in object coding as a picture sequence.