JP2002058033A - Image encoding apparatus and image encoding method - Google Patents

Abstract

(57) Abstract: An image encoding apparatus and an image code capable of improving the coding efficiency of motion-compensated block data and encoding only the motion-compensated block data only. Provide a method of conversion. SOLUTION: A change circuit 350a changes reference block data used at the time of motion compensation for block data to be coded to block data to be referred when a motion vector is assumed to be 0. . The code amount determination circuit 350b uses the block data changed by the change circuit 350a to determine the amount of code that would be generated when coding processing is performed on the block data to be coded. Skip processing circuit 350c
When the determined code amount is equal to or smaller than the predetermined amount, the coding process is skipped for the block data to be coded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image encoding device and an image encoding method for compressing and encoding image data.

[0002]

2. Description of the Related Art Conventionally, MPEG (Moving Picture E-mail) has been used as an image coding method for compressing and coding image data.
xperts Group) standard. In this bidirectional predictive coding method, three types of coding are performed: intra-frame coding, inter-frame forward predictive coding, and bidirectional predictive coding. I (Intra) picture, P (Predictive) picture, and B
(Bidirectionally predictive) Three types of picture types are specified. The P picture and the B picture are also called non-intra pictures or inter pictures.

When encoding image data to be encoded as an intra picture, the image data is encoded, for example, within the same frame (or field). On the other hand, when encoding image data to be encoded as a non-intra picture, encoding is performed on differential image data obtained by referring to a past frame or a future frame.

[0004] For example, there is a hierarchical encoding method as an encoding method for improving image quality step by step.
In this hierarchical coding method, image data to be coded is divided into image data of a plurality of layers, and encoding is performed on the divided image data of each layer. Here, the image data of each layer is, for example, image data divided for each different frequency component.

FIG. 11 shows a configuration of an image coding apparatus of such a hierarchical coding system. This image coding apparatus includes a dividing circuit 170 and coding circuits 171a and 172.
a. The dividing circuit 170 divides the input image data XX as the image data to be encoded into a plurality of (here, two) hierarchical image data (basic hierarchical image data X1 and higher hierarchical image data X2). is there. The encoding circuit 171a encodes the basic hierarchical image data X1 output from the division circuit 170. The encoding circuit 172a encodes the high-order hierarchical image data X2 output from the division circuit 170.

The dividing circuit 170 includes an image processing circuit 170a
And a subtraction circuit 170b. Image processing circuit 1
Reference numeral 70a is for extracting basic hierarchical image data X1, which is image data having basic characteristics, from the input image data XX. The subtraction circuit 170b is for subtracting the basic layer image data X1 from the input image data XX. Here, the basic hierarchical image data is image data that can be viewed as a normal image. For example, in terms of the spatial frequency of an image, it is image data having a low frequency component. The higher hierarchical image data is, for example, image data for obtaining a high-quality image, and is image data having a high frequency component. When dividing the input image data XX with respect to the spatial frequency, the image processing circuit 170a
It is constituted by an F (Low Pass Filter) circuit.

The input image data XX is supplied to an image processing circuit 170a and a subtraction circuit 170b in the division circuit 170, respectively. Image processing circuit 170
"a" represents the input image data XX to the basic hierarchical image data X1.
And outputs the extracted basic layer image data X1 to the encoding circuit 171a and the subtraction circuit 170b, respectively.

The subtraction circuit 170b receives the input image data XX
, The base layer image data X1 output from the image processing circuit 170a is subtracted, and the difference image data obtained as a result of the subtraction is used as the higher layer image data X2 as an encoding circuit 172a
Output.

FIG. 12 shows the encoding circuit 171 shown in FIG.
3 shows the configuration of a. This encoding circuit 171a
Are a pre-processing circuit 151, a subtraction circuit 152, a DCT
(Discrete Cosine Transform) circuit 153 and a quantization circuit 154 are included. The preprocessing circuit 151 rearranges, for example, image data in a raster scan format into a predetermined encoding process order, converts the rearranged image data into a block scan format, and converts the image data of a plurality of macroblocks (hereinafter, referred to as block (Called data). The subtraction circuit 152 is for subtracting, for example, predicted image data described later from the image data (block data) output from the preprocessing circuit 151. The DCT circuit 153 is for converting image data into frequency components, and is for obtaining DCT coefficients by performing DCT on the subtraction result output from the subtraction circuit 151. Quantization circuit 1
Numeral 54 is for quantizing the DCT coefficient output from the DCT circuit 153 based on a predetermined quantization value.

The encoding circuit 171a includes an inverse quantization circuit 158, an inverse DCT circuit 159, and an addition circuit 160
And a frame memory 161. The inverse quantization circuit 158 is for inversely quantizing output data of the quantization circuit 154 (data relating to an intra (I) picture or a P picture used as reference image data for motion compensation). The inverse DCT circuit 159 is
This is for performing inverse DCT on output data (reconstructed DCT coefficients) of the inverse quantization circuit 158. The addition circuit 160 is for adding the output data (image data) of the inverse DCT circuit 159 and the predicted image data. The frame memory 161 is for storing the addition result of the addition circuit 160 as reference image data (reference block data).

Further, the encoding circuit 171a includes a motion compensation circuit 162, a motion vector detection circuit 163, a switch 164, and a control circuit 166. The motion vector detection circuit 163 is for detecting a motion vector based on the image data output from the pre-processing circuit 151 and the reference image data stored in the frame memory 161. Also, the motion vector detection circuit 163
Outputs the detected motion vector to the multiplexing circuit 156 and the encoding circuit 172a, respectively. The motion compensation circuit 162 includes the motion vector detection circuit 16
3 is for performing motion compensation on the reference image data stored in the frame memory 161 based on the motion vector detected by 3 and generating reference image data for motion compensation as predicted image data.

The control circuit 166 determines whether or not to encode the image data output from the preprocessing circuit 151 as an intra picture, and switches the switch 164 according to the determination result.

When the image data output from the preprocessing circuit 151 is encoded as an intra picture, the control circuit 16
6 is determined, the switch 164 switches to the control circuit 166.
Is switched so that data "0" is output to the subtraction circuit 152 and the addition circuit 160, respectively, in accordance with the switching signal output from. When the control circuit 166 determines that the image data output from the preprocessing circuit 151 is to be encoded as a non-intra picture, the switch 164 controls the motion compensation circuit 162 in response to the switching signal output from the control circuit 166. Switching is performed so that the generated predicted image data is output to the subtraction circuit 152 and the addition circuit 160, respectively.

Thus, when the image data is encoded as an intra picture, the subtraction result output from the subtraction circuit 152 is the image data itself. When the image data is encoded as a non-intra picture, the subtraction result is difference image data obtained by using predicted image data.

The encoding circuit 171a includes a variable length encoding circuit 155, a multiplexing circuit 156, and a buffer 157.
And a rate control circuit 165. The variable length coding circuit 155 is for performing variable length coding on output data of the quantization circuit 154. Multiplexing circuit 1
Reference numeral 56 is for multiplexing the encoded data (DCT coefficients, the quantization value of the quantization circuit 154, the picture type, and the like) output from the variable length encoding circuit 155, the motion vector, and the like. The buffer 157 temporarily holds output data of the multiplexing circuit 156 and outputs the data at a predetermined bit rate as a stream. The rate control circuit 165 monitors the data occupation state of the buffer 157 and controls the quantization value of the quantization circuit 154 according to the data occupation state.

FIG. 13 shows the encoding circuit 172 shown in FIG.
3 shows the configuration of a. This encoding circuit 172a is not provided with a motion vector detection circuit 163 as compared with the encoding circuit 171a. Instead, the motion compensation circuit 162 generates predicted image data using the motion vector supplied from the motion vector detection circuit 163 of the encoding circuit 171a. In other respects, the encoding circuit 172a is configured and operates in the same manner as the encoding circuit 171a.

As described above, the encoding circuit 171a
It is assumed that the motion vector detected by the motion vector detection circuit 21 is the optimal motion vector, and when input image data is encoded as a non-intra picture, motion compensation is performed using the motion vector.
Further, the encoding circuit 172a determines that the motion vector supplied from the motion vector detection circuit 163 of the encoding circuit 171a is an optimal motion vector, and encodes input image data as a non-intra picture.
Motion compensation is performed using this motion vector.

[0018]

By the way, in the coding circuit 171a as shown in FIG. 12, the motion vector detected by the motion vector detection circuit 163 may not function optimally at the time of motion compensation. For example, this is a case where the detection accuracy of the motion vector by the motion vector detection circuit 163 is low. Further, as in the case of the image encoding apparatus shown in FIG. 11, a certain encoding circuit (the encoding circuit 171) is used.
If the motion vector used in a) is used as it is in another encoding circuit (encoding circuit 172a), the motion vector does not function optimally, and as a result,
Many block data that are not optimally motion-compensated will be generated. However, in this case, even the block data that is not optimally motion-compensated is encoded, so that the encoding efficiency of the image data is reduced.

The present invention has been made in view of the above problems, and has as its object to improve the coding efficiency of motion-compensated block data and to encode only the motion-compensated block data only. It is an object of the present invention to provide an image encoding device and an image encoding method that can be encoded.

[0020]

According to a first aspect of the present invention, there is provided an image coding apparatus capable of executing a predetermined coding process on block data to be coded, on which motion compensation has been performed. And, using the corresponding block data at a position corresponding to the position of the block data to be coded in another image frame different from the current image frame to which the block data to be coded belongs, to the block data to be coded. Determining means for determining the amount of code that would be generated when coding processing is performed on the block data, and performing coding processing on the block data to be coded based on the determination result of the determining means Control means for determining whether or not to perform coding, and controlling the encoding processing means in accordance with the result of the determination.

An image coding apparatus according to a second aspect of the present invention comprises: coding processing means capable of executing predetermined coding processing on block data to be coded, on which motion compensation has been performed; Means for determining the amount of code that would be generated when the encoding process is performed on the block data to be encoded, and another image different from the current image frame to which the block data to be encoded belongs. Comparing means for comparing corresponding block data at a position corresponding to the position of the block data to be coded in the frame with reference block data used in motion compensation for the block data to be coded; Based on the determination result of the means and the comparison result of the comparing means, it is determined whether or not to perform the encoding process on the block data to be encoded. Depending on the cross-sectional results, and a control means for controlling the encoding means.

An image coding apparatus according to a third aspect of the present invention comprises coding processing means for performing a predetermined coding process on block data to be coded, on which motion compensation has been performed, to obtain coded block data. By using the block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs, Determining means for determining the amount of code that would be generated when the encoding processing is performed, and outputting a stream to the encoded block data obtained by the encoding processing means based on the determination result of the determining means. Processing means for judging whether or not to execute a process, and selectively executing a stream output process for the encoded block data according to the judgment result It is equipped with a.

An image coding apparatus according to a fourth aspect of the present invention comprises coding processing means for performing a predetermined coding process on block data to be coded, on which motion compensation has been performed, to obtain coded block data. Determining means for determining the amount of code of the coded block data obtained by the coding processing means; and determining the coding amount of the coding target block data of another image frame different from the current image frame to which the coding target block data belongs. Comparing means for comparing corresponding block data at a position corresponding to the position of the block data with reference block data used in motion compensation for the block data to be encoded; Based on the result of the comparison, whether or not to execute the stream output process on the encoded block data obtained by the encoding processing means. Cross and, in accordance with the determination result, and a processing means for executing a stream output processing selectively on the coded block data.

An image encoding method according to a first aspect of the present invention is a method of encoding an image frame of another image frame different from the current image frame to which the block data to be encoded subjected to motion compensation belongs.
Using the corresponding block data at a position corresponding to the position of the block data to be encoded, determine the amount of code that would be generated when the encoding process was performed on the block data to be encoded. A step of determining whether or not to perform an encoding process on the block data to be encoded based on the determination result; and encoding the block data to be encoded according to the determination result. Selectively performing a process.

In the image coding method according to the second aspect of the present invention, the step of determining the amount of code that would be generated when coding processing is performed on the block data to be coded, on which motion compensation has been performed. And corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs, and motion compensation for the block data to be encoded Comparing with the reference block data used at the time of the determination, and determining whether or not to perform the encoding process on the block data to be encoded based on the determination result and the comparison result And selectively executing an encoding process on the encoding target block data in accordance with the determination result.

An image encoding method according to a third aspect of the present invention comprises the steps of: performing a predetermined encoding process on motion-compensated block data to be encoded to obtain encoded block data; Encoding processing is performed on the block data to be encoded using block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the target block data belongs. Determining the amount of codes that would be generated when performing the above, and determining whether or not to execute a stream output process on the encoded block data based on the determination result. And selectively performing a stream output process on the encoded block data in accordance with

An image encoding method according to a fourth aspect of the present invention comprises the steps of: performing a predetermined encoding process on motion-compensated block data to be encoded to obtain encoded block data; Determining the amount of code of the coded block data, and corresponding block data at a position corresponding to the position of the block data to be coded in another image frame different from the current image frame to which the block data to be coded belongs Comparing with the reference block data used at the time of motion compensation for the block data to be coded, and executing a stream output process on the coded block data based on the determination result and the comparing means. Determining whether or not the stream is output to the coded block data in accordance with the determination result. And a step of executing processing selectively.

In the image encoding apparatus or the image encoding method according to the first aspect of the present invention, the encoding target of another image frame different from the current image frame to which the block data to be encoded subjected to motion compensation belongs. Using the corresponding block data at a position corresponding to the position of the block data, the amount of codes that would be generated when the encoding process is performed on the block data to be encoded is determined. Then, based on the determination result, it is determined whether or not to perform the encoding process on the block data to be encoded. Based on the determination result, the encoding process on the block data to be encoded is selected. Is executed.

In the image encoding apparatus or the image encoding method according to the second aspect of the present invention, a code which would be generated when encoding processing is performed on the block data to be encoded which has been subjected to motion compensation. The amount of the corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs, and the block data to be encoded Is compared with the reference block data used in the motion compensation for. Then, based on the determination result and the comparison result, it is determined whether or not to perform the encoding process on the block data to be encoded. Conversion processing is selectively executed.

[0030] In the image coding apparatus or the image coding method according to the third aspect of the present invention, a predetermined coding process is performed on the motion-compensated block data to be coded to obtain coded block data. The block data to be coded using block data at a position corresponding to the position of the block data to be coded in another image frame different from the current image frame to which the block data to be coded belongs. The amount of code that would be generated when the encoding process was performed is determined. Then, it is determined whether or not to execute the stream output process on the encoded block data based on the determination result, and the stream output process on the encoded block data is selectively executed according to the determination result.

In the image coding apparatus or the image coding method according to the fourth aspect of the present invention, a predetermined coding process is performed on the motion-compensated block data to be coded to obtain coded block data. The amount of code of the encoded block data is determined, and a corresponding image data of another image frame different from the current image frame to which the encoded block data belongs is located at a position corresponding to the position of the encoded block data. The block data is compared with reference block data used at the time of motion compensation for the block data to be encoded. Then, it is determined whether or not to execute the stream output process on the coded block data based on the determination result and the comparison means. According to the determination result, the stream output process on the coded block data is selectively performed. Be executed.

[0032]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows the configuration of an image coding apparatus according to the present embodiment. Note that the image encoding method according to the present embodiment is embodied by the image encoding device according to the present embodiment, and thus will be described together.

The image coding apparatus shown in FIG. 1 includes a dividing circuit 1 and coding circuits 2a and 3a.

The division circuit 1 includes an image processing circuit 1a and a subtraction circuit 1b. For example, input image data YY as a current image claim is divided into a plurality of (here, two) image data (basic hierarchical image data Y1). And high-level image data Y2). When dividing the input image data YY with respect to the spatial frequency, the image processing circuit 1a is configured by, for example, an LPF circuit.

The input image data YY is supplied to the image processing circuit 1a and the subtraction circuit 1b in the division circuit 1, respectively. The image processing circuit 1a extracts, from the input image data YY, basic layer image data Y1 which is image data having basic components, and outputs the extracted basic layer image data Y1 to the encoding circuit 2a and the subtraction circuit 1b, respectively. It is supposed to.

The subtraction circuit 1b subtracts the basic layer image data Y1 output from the image processing circuit 1a from the input image data YY, and converts the difference image data obtained as a result of the subtraction into higher-layer image data Y2 having an extended component. Is output to the encoding circuit 3a.

The encoding circuit 2a calculates the basic hierarchical image data Y
1 is for encoding, and has a configuration similar to that of the encoding circuit 171a and operates in the same manner. The encoding circuit 2a supplies the detected motion vector to the encoding circuit 3a.

FIG. 2 shows the configuration of the encoding circuit 3a shown in FIG. The encoding circuit 3a is for encoding the higher hierarchical image data Y2, and includes a preprocessing circuit 10, a subtraction circuit 11, a DCT circuit 12,
And a quantization circuit 13. The preprocessing circuit 10 rearranges, for example, raster scan format image data in a predetermined encoding process order, and converts the rearranged image data into a block scan format to obtain a plurality of block data. . The subtraction circuit 11 includes a pre-processing circuit 1
From the image data (block data) output from 0,
For example, predicted image data to be described later is reduced. The DCT circuit 12 obtains a DCT coefficient by performing DCT on the subtraction result output from the subtraction circuit 11. The quantization circuit 13 quantizes the DCT coefficient output from the DCT circuit 12 based on a predetermined quantization value.

The encoding circuit 3a includes an inverse quantization circuit 1
7, an inverse DCT circuit 18, an addition circuit 19, and a frame memory 20. The inverse quantization circuit 17 performs inverse quantization on output data of the quantization circuit 13. The inverse DCT circuit 18 performs an inverse DCT on the output data (the restored DCT coefficient) of the inverse quantization circuit 17.
It is supposed to do. The adding circuit 19 adds the output data (image data) of the inverse DCT circuit 18 and the predicted image data. The frame memory 20
The addition result of the addition circuit 19 is stored as reference image data (reference block data).

Further, the coding circuit 3a includes a motion compensation circuit 22, a switch 23, and a control circuit 29. The motion compensation circuit 22 performs motion compensation on the reference image data stored in the frame memory 20 based on the motion vector supplied from the encoding circuit 2a, and uses the reference image data for motion compensation as predicted image data. Is to occur.

The control circuit 29 determines whether or not the image data output from the preprocessing circuit 10 is to be encoded as an intra picture.
Is switched.

When the control circuit 29 determines that the image data output from the preprocessing circuit 10 is to be encoded as an intra picture, the switch 23 sets the data “0” according to the switching signal output from the control circuit 29. Switching is performed so as to be output to the subtraction circuit 11 and the addition circuit 19, respectively. When the control circuit 29 determines to encode the image data output from the preprocessing circuit 10 as a non-intra picture, the switch 2
Reference numeral 3 designates switching in accordance with a switching signal output from the control circuit 29 such that predicted image data generated in the motion compensation circuit 22 is output to the subtraction circuit 11 and the addition circuit 19, respectively.

Thus, when the input image data is encoded as an intra picture, the subtraction result output from the subtraction circuit 11 becomes the image data itself. When the input image data is encoded as a non-intra picture, the subtraction result is difference image data obtained by using predicted image data, and the difference image data is a motion-compensated image. It corresponds to data (block data).

The encoding circuit 3a includes a skip circuit 3
50, a variable length encoding circuit 14, a multiplexing circuit 15,
It has a buffer 16 and a rate control circuit 24.

The skip circuit 350 determines whether or not to perform the encoding process on the block data to be encoded which has been subjected to the motion compensation, and sends the code to the variable length encoding circuit 14 according to the result of the determination. The conversion process is selectively executed. The skip circuit 350 includes a change circuit 350a, a code amount determination circuit 350b, and a skip processing circuit 350c.

When the control circuit 29 determines that the image data is to be encoded as a non-intra picture, the changing circuit 350a uses the reference used for motion compensation for the block data to be encoded output from the quantization circuit 13. Block data is changed. Specifically, the change circuit 350a replaces the reference block data used in the motion compensation on the block data to be encoded with another block data (for example, the motion vector used in the motion compensation is set to 0). Is changed to block data to be referred to when it is assumed that

Here, reference is made when it is assumed that the reference block data used in the motion compensation for the block data to be encoded and the motion vector used in the motion compensation are 0. The relationship with the power block data will be described. FIG. 3 shows the relationship between these block data. As shown in FIG. 3, with respect to the block data 370a to be coded belonging to the current image frame 370, for example, the block data 371b belonging to the image frame 371 one frame before, which is referred to by the motion vector, is used for the motion compensation. Becomes the reference block data used for Here, for example, assuming that the motion vector used in this motion compensation is 0, the block data 371a belonging to the image frame 371 should be referred to when performing motion compensation on the block data 370a to be encoded. It becomes block data. The block data 371a is corresponding block data at a position corresponding to the position of the block data 370a to be encoded.

When the image data is encoded as a non-intra picture, the code amount determination circuit 350b
Is determined, the changing circuit 3 in the reference image data (block data) stored in the frame memory 20 is used.
Using the block data (corresponding block data described above) changed by 50a, the amount of codes that would be generated when encoding processing is performed on the encoding target block data is determined. ing. The amount of this code is determined, for example, by counting each time block data is input.

The skip processing circuit 350c determines, based on the determination result of the code amount determination circuit 350b, whether or not to execute coding processing on the block data to be coded, on which motion compensation has been performed. According to the result, the variable length coding circuit 14 is made to selectively execute the coding process. Here, when it is determined that the encoding target block data is skipped without performing the encoding process, the skip processing circuit 350c skips the encoding process instead of the encoding target block data. Is output to the variable-length encoding circuit 14.

On the other hand, when the control circuit 29 determines to encode the image data as an intra picture, no motion compensation is performed. Therefore, the skip processing circuit 350c
The block data output from the quantization circuit 13 is output to the variable length encoding circuit 14 without skipping the encoding process.

Here, the skip processing circuit 350c corresponds to a specific example of "control means" of the present invention.

The variable-length encoding circuit 14 includes a skip circuit 3
Variable length coding is performed on 50 output data. The multiplexing circuit 15 encodes the coded data (DCT coefficient, quantization circuit 1) output from the variable length coding circuit 14.
3, a quantization value, a picture type, skip information, etc.), a motion vector, and the like. The buffer 16 temporarily holds the output data of the multiplexing circuit 15 and outputs the data at a predetermined bit rate as a stream. The rate control circuit 24 includes a buffer 16
Is monitored, and the quantization value of the quantization circuit 13 is controlled in accordance with the data occupation state.

Next, the operation of the image coding apparatus configured as described above will be described.

FIG. 4 is a flowchart showing an encoding process by the image encoding apparatus shown in FIG. When the input image data YY is input to the division circuit 1, in step M1, the division circuit 1 divides the input image data YY into basic layer image data Y1 and higher layer image data Y2.
Then, the dividing circuit 1 divides the divided basic hierarchical image data Y
1 is output to the encoding circuit 2a, and the divided higher hierarchical image data Y2 is output to the encoding circuit 3a.

In step M2, the encoding circuit 2a
Operates in the same manner as the conventional encoding circuit 171a, and encodes the basic hierarchical image data Y1 output from the division circuit 1. That is, when encoding the basic layer image data Y1 output from the division circuit 1 as an intra picture, the encoding circuit 2a uses the basic layer image data Y1.
1 is encoded. On the other hand, the basic hierarchical image data Y
When encoding 1 as a non-intra picture, the encoding circuit 2a encodes difference image data obtained by using the basic layer image data Y1 and the prediction image data.

On the other hand, in step M3, the encoding circuit 3a encodes the higher hierarchical image data Y2 output from the division circuit 1 as follows.

The preprocessing circuit 10 rearranges the input high-level image data Y2 in a predetermined coding order, and converts the rearranged high-level image data Y2 into a plurality of block data. The motion compensating circuit 22 performs frame memory 2 based on the motion vector supplied from the encoding circuit 2a.
The motion compensation is performed on the reference image data stored in 0 to generate predicted image data.

If it is determined that the higher hierarchical image data Y2 is to be encoded as a non-intra picture, the control circuit 29
Switches the switch 23 so that the predicted image data generated in the motion compensation circuit 22 is supplied to the subtraction circuit 11 and the addition circuit 19, respectively. As a result, the motion compensation is performed on the higher hierarchical image data Y2.

On the other hand, if it is determined that the higher hierarchical image data Y2 is to be encoded as an intra picture, the control circuit 2
9 indicates that the data “0” indicates that the subtraction circuit 11 and the addition circuit 19
The switch 23 is switched so as to be supplied to the respective switches. As a result, no motion compensation is performed for the higher hierarchical image data Y2.

The subtraction circuit 11 subtracts either the predicted image data or the data “0” from the input high-order hierarchical image data Y 2, and outputs the result of the subtraction to the DCT circuit 12. The DCT circuit 12 obtains a DCT coefficient by performing DCT on the subtraction result of the subtraction circuit 11. The quantization circuit 13 quantizes the DCT coefficient obtained by the DCT circuit 12, and outputs the quantized DCT coefficient to the skip circuit 350 and the inverse quantization circuit 17, respectively. The rate control circuit 24 monitors the data occupation state in the buffer 16 and controls the quantization value of the quantization circuit 13 according to the data occupation state.

The inverse quantization circuit 17 performs inverse quantization on the DCT coefficients quantized by the quantization circuit 13.
The inverse DCT circuit 18 performs an inverse DCT on the DCT coefficient inversely quantized by the inverse quantization circuit 17, thereby restoring image data. The adding circuit 19 adds the restored image data and either the predicted image data supplied through the switch 23 or the data “0”. The frame memory 20 stores the addition result of the addition circuit 19 as reference image data.

Here, the operation of the skip circuit 350 will be described. FIG. 5 is a flowchart showing a skip determination process by the skip circuit shown in FIG. If the control circuit 29 determines that the input high-level image data is to be encoded as a non-intra picture, the quantization circuit 1
The block data to be encoded output from 3 is motion-compensated. Therefore, in step P1, the changing circuit 350a determines that the reference block data used in the motion compensation for this block data is, for example, the motion vector used in the motion compensation is 0. Change to block data to be referenced.

In step P2, the code amount determination circuit 3
Reference numeral 50b denotes a case where the encoding process is performed on the encoding target block data using the block data changed by the changing circuit 350a in the reference image data (block data) stored in the frame 20. To determine the amount of code that would be generated.

In step P3, the skip processing circuit 350c determines whether or not the code amount determined by the code amount determination circuit 350b is larger than a predetermined amount (for example, 0 in this case). If the determined code amount is larger than the predetermined amount, the skip processing circuit 350c determines that the coding process is to be performed without skipping, and outputs the block data to be coded to the variable length coding circuit 14.

On the other hand, if the determined code amount is equal to or less than the predetermined amount, in step P4, the skip processing circuit 35
0c determines to skip without performing the encoding process on the block data to be encoded. Then, the skip processing circuit 350c outputs skip information indicating that the encoding process is skipped to the variable length encoding circuit 14 instead of the block data.

As described above, after the skip circuit 350 performs the skip determination processing, the variable length encoding circuit 14
Performs variable length coding on block data or skip information output from the skip circuit 350,
The obtained encoded data is output to the multiplexing circuit 15.

The multiplexing circuit 15 includes a variable length encoding circuit 14
(DCT coefficients, quantized value of quantization circuit 13, picture type, skip information, etc.) output from, and the motion vector supplied from coding circuit 2a for the block data on which the coding process has been executed. Multiplex and so on. These multiplexed data are temporarily stored in the buffer 16 and then output as a stream at a predetermined bit rate.

As described above, the encoding process for the block data to be encoded which has been subjected to the motion compensation is selectively performed.

(Modification Example of First Embodiment) FIG. 6 shows a configuration of an encoding circuit of an image encoding device according to a modification example of the present embodiment. This image coding apparatus performs skip determination processing on block data on which motion compensation has been performed not only for high-layer image data but also for basic layer image data. For others,
The configuration and the operation are the same as those of the embodiment.

The encoding circuit shown in FIG. 6 corresponds to the encoding circuit 2a shown in FIG. 1, and performs encoding on the basic hierarchical image data. This encoding circuit further includes a motion vector detection circuit 21 as compared with the encoding circuit shown in FIG. The motion vector detection circuit 21 detects a motion vector based on the image data output from the preprocessing circuit 10 and the reference image data stored in the frame memory 20. Then, the motion vector detection circuit 21 outputs the detected motion vector to the motion compensation circuit 22 and the skip circuit 35.
0, the multiplexing circuit 15, and the encoding circuit 3a. The motion compensation circuit 22 performs motion compensation using the motion vector detected by the motion vector detection circuit 21.

In the encoding circuit configured as described above, when encoding the input basic layer image data as a non-intra picture, the skip circuit 350
Performs an encoding process selectively on block data to be encoded based on the above-described skip determination process.

Otherwise, encoding is performed on the basic hierarchical image data in the same manner as in the first embodiment. The higher hierarchical image data is encoded by, for example, the encoding circuit shown in FIG.

As described above, according to the present embodiment, for example, another image frame different from the current image frame to which the motion-compensated block data to be coded belongs.
Using the block data at the position corresponding to the position of the block data to be encoded, the amount of code that would be generated when the encoding process is performed on the block data to be encoded is determined. . Then, based on the determination result, it is determined whether or not to perform the encoding process on the block data to be encoded, and the encoding process is skipped as necessary. Therefore, it is possible to improve the coding efficiency of the motion compensated block data.

(Second Embodiment) FIG. 7 shows a configuration of an encoding circuit of an image encoding device according to the present embodiment. This image encoding apparatus performs a skip determination process (described later) that differs from the skip determination process of the first embodiment with respect to the block data to be encoded on which motion compensation has been performed.
Is performed, and it is determined whether or not to perform the encoding process on the block data to be encoded based on the determination result. In other respects, the configuration and operation are the same as those of the first embodiment.

The image encoding method according to the present embodiment is embodied by the image encoding device according to the present embodiment, and will be described together. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The encoding circuit shown in FIG. 7 corresponds to the encoding circuit 3a shown in FIG. 1, and performs encoding with respect to the higher hierarchical image data. This encoding circuit is provided with a skip circuit 370 instead of the skip circuit 350 as compared with the encoding circuit shown in FIG.

The skip circuit 370 determines whether or not to perform an encoding process on the motion-compensated block data belonging to the current image frame and on which the motion compensation has been performed. The encoding circuit 14 is configured to selectively execute the encoding process. The skip circuit 370 includes a code amount determination circuit 370a, a comparison circuit 370b, and a skip processing circuit 370c.

When the control circuit 29 determines that the current image frame is to be encoded as a non-intra picture, the code amount determination circuit 370a performs an encoding process on the motion-compensated block data to be encoded. Is determined.
Here, the code amount is determined for the block data of the image data itself other than information such as a header and a motion vector.

When the control circuit 29 determines that the current image frame is to be encoded as a non-intra picture, the comparison circuit 370b performs motion compensation on the block data to be encoded based on the motion vector supplied from the encoding circuit 2a. Reference block data (reference image data stored in the frame memory 20) used at the time of
For example, the motion vector used for this motion compensation is 0
In this case, block data to be referred to is read from the frame memory 20 when it is assumed that Then, the comparison circuit 370b stores the frame memory 20
These block data read out from are compared.

The skip processing circuit 370c determines whether or not to execute the encoding process on the motion-compensated block data to be encoded based on the determination result of the code amount determination circuit 370a and the comparison result of the comparison circuit 370b. Is determined, and the variable-length coding circuit 14 selectively performs the coding process according to the result of the determination. Here, when it is determined that the encoding process is skipped without performing the encoding process, the skip processing circuit 370c substitutes skip information indicating that the encoding process is to be skipped, instead of the block data to be encoded, into variable-length encoding. The signal is output to the circuit 14.

On the other hand, when the control circuit 29 determines that the current image frame is to be encoded as an intra picture, no motion compensation is performed. Therefore, the skip processing circuit 370c
Is configured to output the block data to the variable-length encoding circuit 14 without skipping the encoding process on the block data output from the quantization circuit 13.

Next, the operation of skip circuit 370 will be described. FIG. 8 is a flowchart showing the skip determination processing by the skip circuit 370 shown in FIG. When the control circuit 29 determines to encode the input higher-layer image data (current image frame) as a non-intra picture, the block data to be encoded output from the quantization circuit 13 is motion-compensated. Therefore, in step N1, the code amount determination circuit 370a determines the amount of code that would be generated when the encoding process is performed on the block data to be encoded.

Next, in step N2, the skip processing circuit 370c determines whether or not the code amount determined by the code amount determination circuit 370a is larger than a predetermined amount (for example, 0 in this case). If the determined code amount is larger than the predetermined amount, the skip processing circuit 370c determines that the coding process is to be performed without skipping, and outputs this block data to the variable length coding circuit 14.

On the other hand, when the determined code amount is equal to or smaller than the predetermined code amount, there is a possibility that the encoding process is skipped for this block data. Therefore, step N
In 3, the comparison circuit 370b uses the reference block data (stored in the frame memory 20) used in the motion compensation for the block data to be encoded based on the motion vector supplied from the encoding circuit 2a. Reference image data) and, for example, block data to be referred to when the motion vector used in the motion compensation is assumed to be 0 are read from the frame memory 20. Then, the comparison circuit 370b stores the frame memory 20
Are compared with each other.

At step N4, the skip processing circuit 370c determines whether or not these block data read from the frame memory 20 are the same based on the comparison result by the comparison circuit 370b. If the block data is not the same (different), the skip processing circuit 370c performs the motion compensation on the block data to be encoded, and performs the encoding process on the block data to be encoded. It is determined that the image quality deteriorates when skipped. Therefore, the skip processing circuit 370c does not skip the encoding process,
The block data to be encoded is sent to a variable length encoding circuit 1
4 is output.

On the other hand, when these read block data are the same, in step N5, the skip processing circuit 370c determines that the image quality does not deteriorate, and performs the encoding process on the encoding target block data. skip. Then, the skip processing circuit 370c outputs, to the variable length encoding circuit 14, skip information indicating that the encoding process is skipped, instead of the block data.

As described above, the encoding process for the motion-compensated block data to be encoded is selectively performed.

Otherwise, the encoding is performed on the higher hierarchical image data in the same manner as in the first embodiment. The basic hierarchical image data is encoded by, for example, the encoding circuit shown in FIG.

The above-described skip determination processing is not limited to the case where the encoding is performed on the higher hierarchical image data, but can be applied to the case where the encoding is performed on the basic hierarchical image data.

As described above, in the present embodiment, for example, the amount of code that would be generated when coding processing is performed on the block data to be coded, on which motion compensation has been performed, is determined, and the code is determined. When performing motion compensation on the corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs, and the block data to be encoded. The used reference block data is compared. Then, based on the determination result and the comparison result, it is determined whether or not to perform the encoding process on the block data to be encoded, and the encoding process is skipped as necessary. Therefore, it is possible to encode only the block data on which the motion compensation has been appropriately performed without deteriorating the image quality. Further, it is possible to improve the coding efficiency of the block data subjected to the motion compensation.

(Third Embodiment) FIG. 9 shows the configuration of an image coding apparatus according to the present embodiment. This image coding apparatus performs skip determination processing on the coded data after coding the image data on which motion compensation has been performed, and performs stream output processing on the coded block data based on the determination result. Has been determined. In other respects, the configuration and operation are the same as those of the first embodiment.

The image encoding method according to the present embodiment is embodied by the image encoding device according to the present embodiment, and will be described below. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The image encoding device shown in FIG. 9 is different from the image encoding device shown in FIG.
60, a decoding circuit 361, a frame memory 362,
A skip circuit 363 is further provided.

The stream analysis circuit 360 analyzes the syntax of the stream (rule of the coded data sequence) related to the coded data of the high-order image data output from the coding circuit 3a, and encodes the coded block data and the analysis result. (Such as the picture type and the value of the motion vector used for motion compensation) are output to the skip circuit 363.

The decoding circuit 361 decodes a stream related to the encoded data of the higher hierarchical image data output from the encoding circuit 3a, and outputs the decoded data to the frame memory 362.

The frame memory 362 includes a decoding circuit 361.
Is stored as image data (block data).

The skip circuit 363 determines whether or not to perform the stream output process on the coded block data based on the picture type which is the analysis result output from the stream analysis circuit 360, and according to the determination result. Thus, the stream output process is selectively executed. The skip circuit 363 includes the change circuit 36
3a, a code amount determination circuit 363b, and a skip processing circuit 363c.

When the stream analysis circuit 360 determines that the coded data output from the coding circuit 3a has been coded as a non-intra picture, the changing circuit 363a performs the coding corresponding to the coded data. The reference block data used in the motion compensation for the target block data is changed. For example, the change circuit 363a changes the reference block data to block data to be referred to when the motion vector used in the motion compensation is assumed to be 0. In this case, the changed block data is the corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs.

The code amount determination circuit 363 b
The stream analysis circuit 3 determines that the encoded data output from a is encoded as a non-intra picture.
If the determination is made at 60, the frame memory 36 uses the block data changed by the change circuit 363a in the image data stored in the frame memory 362.
2 to determine the amount of codes that would be generated when encoding processing is performed on the encoding target block data corresponding to the encoded data.

The skip processing circuit 363c determines whether or not to execute the stream output process on the coded block data based on the determination result of the code amount determination circuit 363b. The processing is selectively executed. Here, when it is determined that skipping is performed without executing the stream output processing on the encoded block data, the skip processing circuit 36
3c deletes the encoded block data, reconstructs the stream, and outputs the stream.

On the other hand, when the encoded data is encoded as an intra picture, the skip processing circuit 3
63c outputs the coded block data as a stream without skipping the stream output process for the coded block data.

Next, the operation of the image coding apparatus configured as described above will be described.

FIG. 10 is a flowchart showing an encoding process by the image encoding apparatus shown in FIG. When input image data YY, which is image data to be encoded, is input to the dividing circuit 1, in step Q1, the dividing circuit 1
The input image data YY is divided into basic layer image data Y1 and higher layer image data Y2. And the dividing circuit 1
Converts the divided basic hierarchical image data Y1 into an encoding circuit 2a.
, And outputs the divided high-level image data Y2 to the encoding circuit 3a.

In step Q2, the encoding circuit 2a
Operates in the same manner as, for example, the conventional encoding circuit 171a, and outputs the basic hierarchical image data Y1 output from the division circuit 1.
Is encoded. Then, the encoding circuit 2a outputs encoded data of the basic layer image data as a stream.

On the other hand, in step Q3, the encoding circuit 3a operates, for example, in the same manner as the conventional encoding circuit 172a, and outputs the higher hierarchical image data Y output from the dividing circuit 1.
2 is coded. Then, the encoding circuit 3a
The obtained encoded data of the higher hierarchical image data is output to the stream analysis circuit 360 and the decoding circuit 361, respectively.

At step Q4, the stream analysis circuit 360 analyzes the syntax of the stream (rule of the coded data sequence) related to the coded data of the higher hierarchical image data output from the coding circuit 3a. Then, the stream analysis circuit 360 encodes the encoded block data and the analysis result (picture type and motion vector value).
Output to the skip circuit 363.

In step Q5, the decoding circuit 361
Performs decoding of a stream related to the encoded data of the high-order hierarchical image data output from the encoding circuit 3a, and outputs the decoded data to the frame memory 362.

In step Q6, the frame memory 3
Reference numeral 62 stores decoded data output from the decoding circuit 361, for example, image data for at least two frames.

In step Q7, skip circuit 36
3 performs a skip determination process on the encoded block data output from the stream analysis circuit 360 in the same manner as in the flowchart shown in FIG. Encoding circuit 3a
The stream analysis circuit 36 determines that the encoded data output from
When 0 is determined, the change circuit 363a uses the reference block data used in the motion compensation for the block data to be encoded corresponding to the encoded data, for example, in the motion compensation. When the motion vector obtained is assumed to be 0, the motion vector is changed to block data to be referred to.

Next, when the stream analysis circuit 360 determines that the encoded data output from the encoding circuit 3a has been encoded as a non-intra picture, the code amount determination circuit 363b stores the encoded data in the frame memory 362. Using the block data changed by the change circuit 363a in the stored image data, the encoding target block data corresponding to the encoded data stored in the frame memory 362 is encoded. The amount of codes that would be generated when the processing was performed is determined.

The skip processing circuit 363c determines whether the code amount determined by the code amount determination circuit 363b is larger than a predetermined amount (for example, 0 in this case).
When the determined code amount is larger than the predetermined amount, the skip processing circuit 363c determines that the stream output process is to be performed on the encoded block data without skipping. Then, the skip processing circuit 363c outputs the encoded block data as a stream.

On the other hand, when the determined code amount is equal to or less than the predetermined amount, the skip processing circuit 363c determines that the skip is performed without executing the stream output process on the encoded block data. Then, the skip processing circuit 363
c deletes the encoded block data, reconstructs the stream, and outputs the stream.

As described above, the stream output process for the coded block data is selectively performed.

As described above, in the present embodiment, after the block data to be coded belonging to the current image frame is coded as a non-intra picture, for example, Using the block data at the position corresponding to the position of the block data to be encoded, determine the amount of code that would be generated if the encoding process was performed on the block data to be encoded. ing. Then, based on the determination result, it is determined whether or not to execute the stream output process on the encoded block data, and the stream output process is skipped as necessary. Therefore, it is possible to reduce the transmission amount of the coded block data and improve the transmission efficiency.

In the present embodiment, the skip determination processing similar to the skip determination processing based on the flowchart shown in FIG. 5 is not limited to the skip determination processing based on the flowchart shown in FIG. 8, for example. A determination process may be performed.

Further, the skip determination processing of the present embodiment is not limited to the case where the skip determination processing is performed on high-level image data.
The present invention can also be applied to a case where the processing is performed on basic hierarchical image data.

As described above, several embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible.

For example, in a coding method other than the hierarchical coding method, a case where coding processing is performed on motion-compensated image data, or a stream output processing is performed on coded image data. In this case, the present invention can be applied.

In the present invention, encoding is performed on image data of a layer in which image data to be encoded is divided for each different frequency component. For example, encoding is performed on image data of a layer divided for each color component. May be performed.

Further, the motion vector detecting circuit is not limited to being provided in only one of the two encoding circuits as in the case of the image encoding device of the hierarchical encoding method. That is,
In the case of an image encoding device having a plurality of encoding circuits, the motion vector detection circuit may be provided in at least one of the encoding circuits.

[0122]

As described above, the image encoding apparatus according to any one of claims 1 to 3, or the ninth aspect.
According to the image encoding method described in (1), the image data is located at a position corresponding to the position of the encoding target block data of another image frame different from the current image frame to which the motion compensated encoding target block data belongs. Using the corresponding block data, determine the amount of code that would be generated when encoding processing is performed on the block data to be encoded, and based on the determination result, determine the block data to be encoded. It is determined whether or not to perform the encoding process on the block data, and according to the determination result, the encoding process is selectively performed on the block data to be encoded. There is an effect that data encoding efficiency can be improved.

According to the image encoding apparatus of any one of claims 4 to 6, or the image encoding method of claim 10, encoding of the motion-compensated block data to be encoded is performed. Determine the amount of code that would be generated if the processing was performed, and correspond to the position of the block data to be coded in another image frame different from the current image frame to which the block data to be coded belongs. The corresponding block data at the position is compared with the reference block data used in the motion compensation for the block data to be coded, and based on the determination result and the comparison result, the block data to be coded is It is determined whether or not to perform the encoding process on the block data, and according to the result of the determination, the encoding process for the block data to be encoded is selectively executed. Because the, suitably only block data motion compensation is made to be able to encode, also an effect that it is possible to improve the coding efficiency of the block data motion compensation is made.

According to the image coding apparatus of the present invention, a predetermined coding process is performed on the motion-compensated block data to be coded. Block data to be coded by using the block data at a position corresponding to the position of the block data to be coded in another image frame different from the current image frame to which the block data to be coded belongs. The amount of codes that would be generated when encoding processing is performed on block data to be encoded, and whether to perform stream output processing on the encoded block data based on the determination result Is determined, and stream output processing for the encoded block data is selectively executed according to the determination result. Reduce Okuryou an effect that it is possible to improve the transmission efficiency.

According to the image encoding apparatus of the present invention or the image encoding method of the present invention, a predetermined encoding process is performed on the motion-compensated block data to be encoded. To obtain the encoded block data, determine the amount of code of the encoded block data, and determine the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs. Is compared with the reference block data used in the motion compensation for the block data to be coded, and based on the determination result and the comparison means, the coded block data It is determined whether or not to execute the stream output process on the encoded block data. So it was to be executed selectively,
This has the effect of reducing the transmission amount of coded block data for which motion compensation has not been properly performed and improving its transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image encoding device using a hierarchical encoding method according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an encoding circuit shown in FIG.

FIG. 3 is a diagram for explaining a relationship between block data referred to at the time of motion compensation in the encoding circuit shown in FIG. 1;

FIG. 4 is a flowchart illustrating an encoding process performed by the image encoding device illustrated in FIG. 1;

FIG. 5 is a flowchart illustrating a skip determination process performed by a skip circuit illustrated in FIG. 2;

FIG. 6 is a block diagram illustrating a configuration of an encoding circuit of an image encoding device that is a modification example according to the first embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of an encoding circuit of an image encoding device according to a second embodiment of the present invention.

FIG. 8 is a flowchart illustrating a skip determination process by a skip circuit illustrated in FIG. 7;

FIG. 9 is a block diagram illustrating a configuration of an image encoding device according to a third embodiment of the present invention.

10 is a flowchart illustrating an encoding process performed by the image encoding device illustrated in FIG. 9;

FIG. 11 is a block diagram illustrating a configuration of a conventional image coding apparatus using a hierarchical coding method.

FIG. 12 is a block diagram illustrating a configuration of an encoding circuit illustrated in FIG. 11;

FIG. 13 is a block diagram showing a configuration of the encoding circuit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Division circuit, 1a ... Image processing circuit, 1b, 11 ... Subtraction circuit, 2a, 3a ... Encoding circuit, 10 ... Preprocessing circuit, 1
2 DCT circuit, 13 quantization circuit, 14 variable-length coding circuit, 15 multiplexing circuit, 16 buffer, 17 inverse quantization circuit, 18 inverse DCT circuit, 19 addition circuit, 2
0, 362: Frame memory, 21: Motion vector detection circuit, 22: Motion compensation circuit, 23: Switch, 24: Rate control circuit, 29, 54: Control circuit, 350, 36
3,370: skip circuit, 350a, 363a: change circuit, 350b, 363b, 370a: code amount determination circuit, 350c, 363c, 370c: skip processing circuit, 360: stream analysis circuit, 361: decoding circuit
370b a comparison circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) BC01 BC02 BC08 BC14 BC16 BC25 BD01

Claims (12)

[Claims] 1. An apparatus for converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, comprising: a motion-compensated block to be encoded. Encoding processing means capable of executing a predetermined encoding process on the data, at a position of the encoding target block data of another image frame different from the current image frame to which the encoding target block data belongs; A determining unit that determines an amount of a code that will be generated when an encoding process is performed on the encoding target block data using a corresponding block data at a corresponding position; and Based on the determination result, it is determined whether or not to perform the encoding process on the block data to be encoded, and the encoding processing unit is controlled according to the determination result. An image encoding apparatus comprising: 2. The encoding unit according to claim 1, wherein the encoding unit is configured to skip encoding of the block data to be encoded when the amount of the code determined by the determining unit is equal to or less than a predetermined amount. The image encoding device according to claim 1, wherein the image encoding device performs control. 3. The image encoding apparatus according to claim 1, wherein said one image frame is an image frame of each layer obtained by dividing an original image frame into image components of a plurality of layers. apparatus. 4. An apparatus for converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, the motion-compensated block being encoded. Encoding processing means capable of executing predetermined encoding processing on data; and the amount of codes that would be generated when the encoding processing means performed encoding processing on the block data to be encoded. Determining means for determining, the corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the block data to be encoded belongs, and the code Comparing means for comparing the reference block data used in the motion compensation with respect to the block data to be converted; A control unit that determines whether or not to perform an encoding process on the block data to be encoded based on a comparison result of the comparison unit, and that controls the encoding processing unit in accordance with the determination result. An image encoding device comprising: 5. The control means, if the amount of the code determined by the determination means is equal to or less than a predetermined amount, and if the corresponding block data matches the reference block data in the comparison means, 5. The image coding apparatus according to claim 4, wherein said coding processing means is controlled so as to skip coding processing for block data to be converted. 6. The image coding apparatus according to claim 4, wherein said one image frame is an image frame of each layer obtained by dividing an original image frame into image components of a plurality of layers. apparatus. 7. An apparatus for converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, wherein the motion-compensated block to be encoded is Coding processing means for performing predetermined coding processing on data to obtain coded block data; and, for another image frame different from the current image frame to which the block data to be coded belongs, Using block data at a position corresponding to the position of the block data, determining means for determining the amount of code that would be generated when performing encoding processing on the block data to be encoded, Determining whether to execute a stream output process on the coded block data obtained by the coding processing unit based on a result of the determination by the determining unit; And a processing unit for selectively executing a stream output process on the encoded block data in accordance with a result of the determination. 8. An apparatus for converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, the motion-compensated block being encoded. Coding processing means for performing predetermined coding processing on data to obtain coded block data; determining means for determining a code amount of coded block data obtained by the coding processing means; Block data of another image frame different from the current image frame to which the block data to be encoded belongs, at a position corresponding to the position of the block data to be encoded; and motion compensation for the block data to be encoded. Comparing means for comparing with the reference block data used at the time of the determination, based on the determination result of the determining means and the comparison result of the comparing means. And determining whether or not to execute a stream output process on the encoded block data obtained by the encoding processing means, and selectively executing the stream output process on the encoded block data according to the determination result. An image encoding device comprising: processing means. 9. A method of converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, wherein the motion-compensated block to be encoded is An encoding process is performed on the block data to be encoded by using corresponding block data at a position corresponding to the position of the block data to be encoded in another image frame different from the current image frame to which the data belongs. Determining the amount of code that would be generated when performing the above, and determining whether to execute an encoding process on the block data to be encoded based on the determination result And selectively performing an encoding process on the block data to be encoded according to a result of the determination. Method. 10. A method for converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, wherein the motion-compensated block to be encoded is provided. Determining the amount of code that would be generated if the encoding process was performed on the data; and the encoding target of another image frame different from the current image frame to which the encoding target block data belongs. Comparing the corresponding block data at the position corresponding to the position of the block data with the reference block data used at the time of the motion compensation for the block data to be coded; and the determination result and the comparison result Determining whether or not to execute the encoding process on the encoding target block data based on Depending on the result, the image coding method characterized by comprising the step of performing a coding process for the block data of the encoding target selectively. 11. A method for converting one image frame into a plurality of block data, and performing an encoding process with motion compensation on each of the converted block data, comprising: a motion-compensated block to be encoded. Performing a predetermined encoding process on the data to obtain encoded block data; anda different image frame different from the current image frame to which the encoding target block data belongs, of the encoding target block data. Using the block data at the position corresponding to the position to determine the amount of code that would be generated when coding processing is performed on the block data to be coded; and Determining whether or not to execute a stream output process on the encoded block data based on the determination result. Image coding method which comprises the step of selectively executing a stream output processing for Goka block data. 12. A method of converting one image frame into a plurality of block data and performing an encoding process with motion compensation on each of the converted block data, wherein the motion-compensated block to be encoded is provided. Performing predetermined coding processing on the data to obtain coded block data; determining the amount of code of the coded block data; and a current image frame to which the block data to be coded belongs. Comparing the corresponding block data at a position corresponding to the position of the block data to be coded of another different image frame with the reference block data used in the motion compensation for the block data to be coded. And outputting a stream to the encoded block data based on the determination result and the comparison means. And determining whether to perform the management, in accordance with this determination result, the image coding method characterized by comprising the step of performing the stream output processing selectively for the coded block data.