JP2004088135A - Image encoder and image decoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image encoder and an image decoder wherein dissidence between encoding processing and decoding processing of an image associated with an area reallocation (reallocation of a storage capacity of storage areas of a long time memory and a short time memory) is avoided. <P>SOLUTION: The image encoder is provided with: a frame memory for storing frames to two kinds of memories, that is, the short time memory adopting the first-in first-out system and the long time memory adopting the random access system; and a missing short time memory detection section 150 that decides a memory area in which the frame is stored at the oldest time in the short time memory and makes the memory area available for the long time memory through a long time memory deallocating section 133. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image encoding method and an image encoding device for efficiently encoding a moving image signal using correlation between screens, and an image decoding method and an image decoding device for decoding an encoded signal. And a recording medium on which a program for executing the same by software is recorded.
[0002]
[Prior art]
In recent years, the multimedia era, in which voices, images, and other pixel values are integrated, has been approached, and the traditional information media, that is, means for transmitting information such as newspapers, magazines, televisions, radios, and telephones, to humans has been developed. It has been taken up as an object. Generally, multimedia means not only characters, but also figures, sounds, and especially images, etc., that are simultaneously associated with each other. Is an essential condition.
[0003]
However, when the amount of information of each of the above information media is estimated as a digital information amount, the amount of information per character is 1 to 2 bytes in the case of characters, while 64 kbits per second in the case of voice (telephone quality). In addition, for a moving image, an information amount of 100 Mbits per second (current television reception quality) or more is required, and it is not realistic to handle the vast amount of information in the above-mentioned information medium in a digital form. For example, a videophone has already been put into practical use by an Integrated Services Digital Network (ISDN) having a transmission rate of 64 kbps to 1.5 Mbps, but it is impossible to send a video of a video camera directly through the ISDN. It is possible.
[0004]
Therefore, what is needed is an information compression technology. For example, in the case of a videophone, H.264 standardized internationally by ITU (International Telecommunication Union Telecommunication Standardization Sector). 261 and H.E. H.263 video compression technology is used. In addition, according to the information compression technology of the MPEG-1 standard, it is possible to store image information together with audio information in a normal music CD (compact disc).
[0005]
Here, MPEG (Moving Picture Experts Group) is an international standard for digital compression of moving picture plane signals, and MPEG-1 converts moving picture plane signals up to 1.5 Mbps, that is, information of television signals by about 1/100. It is a standard that compresses up to. In addition, since the transmission rate for the MPEG-1 standard is mainly limited to about 1.5 Mbps, the moving picture signal is 2 to 2 in MPEG-2, which is standardized to meet the demand for higher image quality. It is compressed to 15 Mbps.
[0006]
Further, at present, MPEG-4, which has a higher compression ratio, has been standardized by a working group (ISO / IEC JTC1 / SC29 / WG11), which has been standardizing MPEG-1 and MPEG-2. MPEG-4 initially introduced not only high-efficiency coding at low bit rates, but also a strong error resilience technique that can reduce subjective image quality degradation even if a transmission path error occurs. . In addition, ISO / IEC and ITU have been jointly working on the standardization of JVT (Joint Video Team) as a next-generation screen coding system, and the one called Joint Model 1 (JM1) is the latest at the present time.
[0007]
FIG. 16 is a block diagram of an image encoding device assumed from the conventional image encoding method and the memory management method studied in JM1. This image coding apparatus includes a motion detection unit 101, a frame memory 102, a motion compensation unit 103, a subtraction unit 104, an orthogonal transformation unit 105, a quantization unit 106, an inverse quantization unit 107, an inverse orthogonal transformation unit 108, and an addition unit 109. Variable length encoding section 110, long time memory size holding section 130, memory size comparing section 131, lost long time memory detecting section 132, long time memory opening section 133, short time memory opening section 134, long time memory moving section 135 , And a management information encoding unit 136.
[0008]
First, the operation of encoding an image will be described. The motion detection unit 101 compares the input image Vin with the reference image M1 in the frame memory 102, specifies the reference image number Idx indicating the reference image having the smallest difference between the input image Vin and the motion vector that is the motion amount of the pixel. The MV is calculated and output to the frame memory 102 and the variable length coding unit 110.
[0009]
The motion compensation unit 103 reads out the pixels of the area indicated by the reference image number Idx and the motion vector MV from the frame memory 102 as a motion compensation reference image M2, performs a predetermined operation, generates a motion compensation image M3, and Output to 109.
[0010]
The subtraction unit 104 calculates a residual image M4, which is a difference value between the input image Vin and the motion compensation image M3, and outputs the result to the orthogonal transformation unit 105. The orthogonal transformation unit 105 converts the frequency of the residual image M4 into the frequency domain. The component M5 is output to the quantization unit 106. Further, the quantization unit 106 quantizes the frequency component M5, and outputs a quantization value M6 of the motion compensation error to the inverse quantization unit 107 and the variable length coding unit 110.
[0011]
Further, the inverse quantization unit 107 inversely quantizes the quantized value M6 and outputs a decoded frequency component M7 to the inverse orthogonal transform unit 108. The inverse orthogonal transform unit 108 is a pixel difference value from the frequency domain of the decoded frequency component M7. The decoding residual image M8 is calculated and output to the adding unit 109.
[0012]
The adding unit 109 calculates the decoded image signal M9 by adding the decoded residual image M8 and the motion compensation image M3, and stores the decoded image signal M9 in the frame memory 102.
On the other hand, the variable length coding unit 110 codes the motion vector MV, the reference image number Idx, the quantization value M6, and the management information MMCO from the management information coding unit 136 described later, and outputs a coded signal str to the outside. I do.
[0013]
FIGS. 17A and 17B are explanatory diagrams of the image management method, and show a state in which a short-term memory and a long-term memory are respectively secured in the frame memory 102 serving as a reference image memory. The number of memory areas including the short-term memory and the long-term memory is determined, and the total number of usable images (frames) stored therein is determined.
[0014]
Therefore, by encoding the number of memory areas LTsize of the long-term memory,
Number of memory areas of short-time memory STsize = total number of memory areas−number of memory areas of long-time memory LTsize
As a result, the memory area number STsize of the short-time memory is obtained. A reference image number Idx is assigned to each area where the reference image is stored. Then, the reference image is identified by the reference image number Idx. In the short-term memory and the long-term memory, there is an area (unused) in which an image is not yet stored, but the reference image number Idx is not assigned to this area.
[0015]
When encoding / decoding is performed with reference to an image, an image to be referred to as a forward image is represented by a reference image number Idx.
In video coding, an arbitrary image (frame) can be selected as a reference image from a plurality of images (frames) as a forward reference image. FIG. 18 is an explanatory diagram of image encoding using a short-time memory. The short-time memory stores several pictures decoded immediately before, and is a reference picture of a so-called MPEG-1 or MPEG-2 P picture (forward predictive coded picture) and B picture (bidirectional predictive coded picture). Is equivalent to
[0016]
FIG. 18A is a prediction example of a P picture. In a P picture, only an I picture or a P picture can be referred to. Frame 3 refers to Frame 0, Frame 6 refers to Frame 0 or Frame 3, and Frame 9 refers to Frame 0, Frame 3, or Frame 6 for encoding / decoding.
[0017]
FIG. 18B is a prediction example of a B picture. In a B picture, an I picture and a P picture can be referred to as forward images. The back image can refer to one temporally closest picture in the I picture or the P picture. Frame 1 and Frame 2 refer to Frame 0 forward, Frame 4 and Frame 5 refer to Frame 0 or Frame 3, and Frame 7 and Frame 8 refer to Frame 0, Frame 3 or Frame 6 for encoding / decoding. Can be done.
In the prediction of a B picture, in some cases, a B picture is referred to as a forward picture in addition to an I picture and a P picture.
[0018]
FIG. 19 is an explanatory diagram of image encoding using a long-term memory. The short-term memory stores several images that were temporally (encoded and) decoded, whereas the long-term memory explicitly stores images and discards the stored contents regardless of the passage of time. Is what you do. For example, if a surveillance camera switches between multiple cameras and shoots, if the final decoded image for each camera is stored in the long-term memory, the last time the same camera is used to shoot the same If the difference value between the image and the image stored in the memory is encoded, the correlation between the images is high and the compression ratio can be improved.
[0019]
It can be seen from FIG. 19 that LTFrame0, LTFrame1, LTFrame2, and LTFrame3 which are screens at times older than the short-time memory shown in FIG. 18 are referenced as reference images of the target image CurFrame. The LTFrame 0, LTFrame 1, LTFrame 2, and LTFrame 3 are stored in the memory for a long time.
[0020]
Next, the operation of managing the memory secured in the frame memory 102 will be described.
When the long-time memory size change signal LTS is input from the outside, the new size of the long-time memory by the long-time memory size change signal LTS is held in the long-time memory size holding unit 130. Then, the memory size comparing unit 131 compares the current memory size already held in the long-time memory size holding unit 130 with a new memory size based on the long-time memory size change signal LTS. Here, the memory size of the long-time memory corresponds to the number of memory areas.
[0021]
Next, when the memory size of the long-term memory is reduced according to the comparison result of the memory size comparing unit 131, the long-term memory releasing unit 133 releases the memory area determined by the lost long-term memory detecting unit 132, and Put it in use.
At this time, the unused memory area of the long time memory can be used as the memory area of the short time memory.
[0022]
Further, the long-time memory release unit 133 releases the memory area indicated by the long-time memory release signal LTD, which is an external signal, to make it unused. Then, the short-time memory release unit 134 receives the short-time memory release signal STD input from the outside, and sets the memory area of the short-time memory in the frame memory 102 to an unused state.
[0023]
Further, the long-time memory moving unit 135 receives the long-time memory moving signal LTM input from the outside, and transfers the contents stored in the short-time memory memory area in the frame memory 102 to the long-time memory memory area. Move.
The long-time memory size change signal LTS, the long-time memory release signal LTD, the short-time memory release signal STD, and the long-time memory movement signal LTM are encoded by the management information encoding unit 136, and the management information MMCO Is output to the variable length coding unit 110.
[0024]
FIGS. 17A and 17B show states before and after changing the memory areas of the long-term memory and the short-term memory, respectively. In FIG. 17A, the memory size STsize of the short-time memory is composed of six memory areas each storing a frame whose image reference number Idx is indicated by 0 to 5, and one memory area in an unused state. The memory size LTsize of the long-time memory includes three memory areas each storing a frame whose image reference number Idx is indicated by 6 to 8, and one unused memory area.
[0025]
The hatched memory area is a used state in which a frame is stored, and the non-hatched memory area is an unused state.
At this time, the unused state is, for example, a state in which the memory area is set to be unused by a flag or the like.
[0026]
In FIG. 17B, the memory size LTsize of the long-term memory is composed of two memory areas, and the memory size STsize of the short-term memory is composed of nine memory areas. The size STsize increases, and the memory size LTsize of the long-term memory decreases.
On the other hand, FIGS. 20A and 20B show the state before and after the change of each memory area of the short-term memory and the long-term memory, and the memory size STsize of the short-term memory decreases after the change. ing.
[0027]
FIG. 21 is a block diagram of an image decoding device assumed from the conventional image decoding method, and decodes an encoded signal str encoded by the image encoding device shown in FIG.
In FIG. 21, the same operations as those in the block diagram of the image encoding device shown in FIG. 16 are denoted by the same reference numerals, and description thereof will be omitted.
[0028]
The variable length decoding unit 120 decodes the encoded signal str, outputs the motion vector MV and the reference image number Idx to the frame memory 102, outputs the motion compensation error quantization value M6 to the inverse quantization unit 107, The management information MMCO is output to the management information decoding unit 236.
Further, the quantized value M6 is input to the adding unit 109 as a decoded residual image M8 via the inverse quantization unit 107 and the inverse orthogonal transform unit 108.
[0029]
The motion compensation unit 103 reads out the pixels in the area indicated by the reference image number Idx and the motion vector MV from the frame memory 102 as the motion compensation reference image M2, performs a predetermined operation, calculates the motion compensation image M3, and Output to 109.
The addition unit 109 outputs the decoded image Vout by adding the decoded residual image M8 and the motion compensation image M3, and outputs the decoded image Vout to the frame memory 102 for reference in decoding a subsequent image.
[0030]
Further, the management information decoding unit 236 acquires and decodes the management information MMCO from the variable length decoding unit 120, and transmits the long-term memory size change signal LTS to the frame memory 102, the long-term memory size holding unit 130, the memory size comparing unit 131, and outputs a long-term memory movement signal LTM to the long-time memory movement unit 135. Further, the management information decoding unit 236 outputs the long-time memory release signal LTD to the long-time memory release unit 133 and outputs the short-time memory release signal STD to the short-time memory release unit 134.
The operation of setting the memory areas of the short-term memory and the long-term memory to the unused state and changing the respective memory areas is the same as that of the image encoding apparatus of FIG.
[0031]
With the above configuration, the encoded signal str encoded by the image encoding device in FIG. 16 can be correctly decoded.
As described above, the frame memory is divided into the long-term memory and the short-term memory to store the reference image, thereby achieving the compression efficiency.
[0032]
[Problems to be solved by the invention]
However, with the above-described configuration, when the memory size of the short-time memory is reduced when the memory area is changed (when the area of the frame memory is redistributed), the memory area in the short-time memory is set to the unused state. However, if some care is not taken, the inconvenience that the latest data in the memory is erased for a short time occurs. Therefore, a mismatch occurs between the encoding process and the decoding process.
[0033]
The present invention has been made in order to solve the above-described problem, and has been made in consideration of an image encoding process associated with an area reallocation of a frame memory (a reallocation of a storage capacity of a storage area of a long-time memory and a short-time memory). An object of the present invention is to provide an image encoding device and an image decoding device that avoid mismatching of decoding processing.
[0034]
[Means for Solving the Problems]
In order to achieve the above object, an image encoding apparatus according to the present invention is an apparatus for encoding while comparing an input image with a reference image, wherein the first storage area and the second storage area have different data read / write methods. Storage means for dividing the reference image into two storage areas and storing the reference image, and the oldest first storage area having a smaller storage capacity when the storage capacity of the first and second storage areas is redistributed. A redistribution unit is provided for setting a storage area in which a reference image is stored at a time to a state where the storage area can be used as a second storage area having a large storage capacity.
[0035]
A decoding unit that decodes the input image while comparing the input image with the reference image, the storage unit configured to store the reference image by dividing the image into a first storage area and a second storage area having different data read / write schemes; When redistributing the storage capacity of the first and second storage areas, the storage area in which the reference image is stored at the earliest time in the first storage area having the smaller storage capacity is increased. And a redistribution unit for making the storage area usable as a second storage area.
[0036]
An image encoding method using a storage unit that stores a reference image by dividing into a first storage area and a second storage area having different data read / write methods, wherein the first and second storage areas When the reallocation of the storage capacity is performed, the storage area in which the reference image is stored at the oldest time in the first storage area where the storage capacity becomes small can be used as the second storage area where the storage capacity becomes large. It is characterized by being in a state.
[0037]
An image decoding method using storage means for storing a reference image by dividing into a first storage area and a second storage area having different data read / write methods, wherein the first and second storage areas are provided. When the reallocation of the storage capacity is performed, the storage area in which the reference image is stored at the oldest time in the first storage area where the storage capacity becomes small can be used as the second storage area where the storage capacity becomes large. It is characterized by being in a state.
[0038]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
Hereinafter, an image encoding device according to the first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to the first embodiment of the present invention.
The image encoding apparatus includes a motion detection unit 101, a frame memory 102, a motion compensation unit 103, a subtraction unit 104, an orthogonal transformation unit 105, a quantization unit 106, an inverse quantization unit 107, an inverse orthogonal transformation unit 108, an addition unit 109, Long-term memory size holding unit 130, memory size comparing unit 131, lost long-term memory detecting unit 132, long-term memory releasing unit 133, lost short-term memory detecting unit 150, short-time memory releasing unit 134, long-term memory moving unit 135 , And a management information encoding unit 136.
[0039]
Devices that perform the same operations as in the block diagram of the image encoding device in FIG. 16 are denoted by the same reference numerals.
Motion detection section 101, frame memory 102, motion compensation section 103, subtraction section 104, orthogonal transformation section 105, quantization section 106, inverse quantization section 107, inverse orthogonal transformation section 108, addition section 109, variable length encoding section 110 Is the same as in FIG. 16, and a description thereof will be omitted.
[0040]
First, the configuration of management of the frame memory 102 in the present image encoding device will be described.
The long-time memory size holding unit 130 is a holding unit that receives a long-term memory size change signal LTS input from the outside and sequentially holds a new memory size of the long-term memory. Then, the memory size comparing unit 131 compares the memory size currently held in the long time memory size holding unit 130 with the new memory size set by the long time memory size change signal LTS, and loses the comparison result. It outputs to the long-term memory detection unit 132 and the lost short-time memory detection unit 150.
[0041]
The lost long-term memory detection unit 132 receives the comparison result of the memory size comparison unit 131, determines a memory area of the long-term memory in which the stored contents are to be unused, and sends the memory area to the long-term memory release unit 133. A signal indicating the address of the area is output.
On the other hand, based on the comparison result of the memory size comparing unit 131, the lost short-time memory detecting unit 150 determines a memory area of the short-time memory in which the stored content is to be in an unused state, and sends the memory area to the short-time memory releasing unit 134. A signal indicating the address of the memory area is output.
[0042]
The long-time memory release unit 133 sets the memory area indicated by the lost long-time memory detection unit 132 in the long-term memory of the frame memory 102 to an unused state, and inputs a long-term memory release signal LTD input from the outside. The memory area indicated by is set to an unused state.
Here, the unused state is a state in which the memory area is set as an unused state by a flag or the like.
[0043]
The short-time memory release unit 134 sets the memory area indicated by the lost short-time memory detection unit 150 in the short-time memory of the frame memory 102 to an unused state, and releases the short-time memory input from the outside. The memory area indicated by the signal STD is set to an unused state.
[0044]
In the present invention, the lost short-time memory detection unit 150 puts the short-time memory in the unused state sequentially from the memory area stored at the oldest time.
Further, the memory size change signal LTS, the long-time memory release signal LTD, the short-time memory release signal STD, and the long-time memory movement signal LTM are encoded by the management information encoding unit 136, so that the management information MMCO has a variable length. Output to encoding section 110
[0045]
In the present embodiment, the short-term memory secured in the frame memory 102 is a first-in first-out (FIFO) memory. When a new memory is stored, the stored contents having the oldest stored time are discarded in order. An image of the latest fixed number of frames is always stored. Unnecessary images can be explicitly opened. Then, only the image whose time is close is stored, and is used for the same purpose as the reference image used in normal MPEG1 / 2.
[0046]
On the other hand, the long-time memory is a memory of a random access system, and has a configuration in which a frame can be stored in an arbitrary area and a frame stored in an arbitrary area can be read. The long-time memory stores images referred to after a long time, such as a background image and an image before scene insertion (immediately before the start of insertion when another scene is inserted into one scene). Also stores a reference image for a long time.
[0047]
When storing in the long-term memory, the data stored in the short-term memory is moved to the long-term memory, and the long-term memory moving unit 135 receives the long-term memory move signal LTM, and Of the memories stored in the memory 102, the storage contents stored in the memory area of the short-time memory are moved to the memory area of the long-time memory.
[0048]
The operation of the image encoding apparatus having the above configuration when receiving the memory size change signal LTS for a long time in four cases will be described.
[0049]
First, the operation in the first case will be described with reference to the flowchart in FIG. 2 and the diagram showing changes in the memory area in FIG. First, when the storage capacity of the long-term memory and the short-term memory is redistributed, the reduced memory area is first unallocated when the memory area of the long-term memory decreases or increases. This is an example in which the memory size of each memory is changed after the state of use is changed.
[0050]
FIG. 3 is a diagram showing the states of the long-term memory and the short-term memory among the memories of the frame memory 102. In FIG. 3, there are eleven memory areas from memory area numbers A0 to A10 as shown in the memory 31, the memory areas with diagonal lines are used, and the memory areas without diagonal lines are unused.
[0051]
The short-term memory has seven memory areas from memory area numbers A0 to A6, and the long-term memory has four memory areas from memory area numbers A7 to A10. The area is divided into a time memory area L. Here, the number of memory areas in the short-time memory area S corresponds to the memory size of the short-time memory, and the number of memory areas in the long-time memory area L corresponds to the memory size of the long-time memory.
[0052]
In the short-term memory area S, the time at which the memory is stored in the memory in the order of the memory area number A0 to the memory area number A6 becomes old, and the memory of the memory area number A6 is unused.
[0053]
First, when the long-time memory size change signal LTS is input from the outside, the memory size comparison unit 131 compares the current memory size already held in the long-time memory size holding unit 130 with the long-time memory size change signal LTS. Compare with the new memory size. That is, a process of determining whether to change the memory size is performed (step S1).
[0054]
If it is determined in the comparison result of the memory size comparing unit 131 that there is no change in the memory size of the long-time memory (N in step S1), the process ends, but it is determined that there is a change in the memory size (step S1). In step S2, a determination process is performed to determine whether or not to reduce the memory area of the long-term memory based on the comparison result of the memory size comparison unit 131 (step S2).
[0055]
Then, when it is determined that the memory area of the long-term memory is to be reduced (for example, the two memory areas are reduced) (Y in step S2), the long-term memory releasing unit 133 The memory area determined by the long-time memory detection unit 132 is set in an unused state (step S3).
That is, it becomes the memory 32 in FIG. 3, and the memory areas of the memory area numbers A7 and A8 are in an unused state.
[0056]
Subsequently, the lost long-term memory detection unit 132 stores the unused memory area of the long-term memory in addition to the short-term memory as belonging to the short-term memory, and stores the long-term memory area L and the short-term memory The memory size of the area S is changed (Step S4).
[0057]
This state is the memory 33 in FIG. 3, the boundary between the long-term memory area L and the short-term memory area S is changed from K1 to K2, and the short-term memories are nine memory areas from memory area numbers A0 to A8. The storage capacities of the long-term memory and the short-term memory are redistributed so that the long-term memory becomes two memory areas of memory area numbers A9 and A10.
Here, in order to make the memory area of the long-term memory usable as a short-term memory, the memory area is set to an unused state as an example.
[0058]
On the other hand, when the memory size comparison unit 131 determines that the memory area of the long-term memory is not to be reduced (N in step S2) in the above-described determination process (step S2) of determining whether to reduce the memory area of the long-term memory. Assuming that the memory area of the short-time memory is reduced (for example, the three memory areas are reduced), the short-time memory release unit 134 sets the memory area of the short-time memory in order from the memory area in which the time at which the frame is stored is oldest. An unused state is set (step S5). At this time, the memory area to be unused is determined by the short-time memory detector 150.
[0059]
This state is indicated by the memory 34 in FIG. 3, and three memory areas (memory area numbers A6, A5, and A4) stored in the short time memory area S at the oldest time become unused. In this case, since the memory area of the memory area number A6 is unused from the beginning, the short-time memory release unit 134 sets the memory areas of the memory area numbers A5 and A4 to the unused state.
[0060]
Then, the short-time memory detection unit 150 stores the unused memory area of the short-time memory in addition to the long-time memory as belonging to the long-time memory, and stores the long-time memory area L and the short-time memory area S Change the memory size of
[0061]
This state is the memory 35 in FIG. 3, the boundary between the short-term memory area S and the long-term memory area L is changed from K1 to K3, and the short-term memory area S is divided into four memory areas A0 to A3. Then, the storage capacities of the long-term memory and the short-term memory are redistributed so that the long-term memory area L becomes seven memory areas from memory area numbers A4 to A10 (step S4).
[0062]
Such processing is performed for each memory area by a table storing whether the memory area belongs to the short-time memory or the long-time memory, whether the memory area is used, or whether the memory area is used. This can be easily performed by providing a table for storing the presence or absence.
[0063]
Next, the operation in the second case will be described with reference to the flowchart in FIG. 4 and the diagram showing the change in the state in FIG. Second, when redistributing the storage capacities of the long-term memory and the short-term memory, in both cases where the memory area of the long-term memory decreases and increases, This is an example in which the memory size of each memory of the memory is changed, and then one of the memories is moved to the other memory with one decreasing memory area being unused.
[0064]
The memory 51 in FIG. 5 has the same configuration as the memory 31 in FIG.
First, the flowchart of FIG. 4 differs from that of FIG. 2, that is, when the memory size comparison unit 131 determines that the memory size is to be changed (Y in step S1) in the process of determining whether to change the memory size (step S1). The processing will be described. When the memory size comparing unit 131 determines that the memory size is changed, the lost long-term memory detection unit 132 or the short-term lost memory detection unit 150 sets the long-term memory area L and the short-term memory area L in accordance with the comparison result of the memory size comparison unit 131. Change the boundary of the memory area S.
[0065]
In this case, when the memory size of the long-term memory area L becomes smaller, the boundary between the long-term memory area L and the short-term memory area S changes from K1 to K2 as shown in the memory 52 of FIG. When the memory size of the area S becomes smaller, the boundary is changed from K1 to K3 as shown in the memory 54 of FIG. (Step S11).
Subsequently, a process (step S12) of determining whether to reduce the memory area of the long-term memory by the memory size comparing unit 131 is performed.
[0066]
At this time, when it is determined that the memory area of the long-term memory is to be reduced (Y in step S12), the boundary between the short-term memory area S and the long-term memory area L is determined as shown in the memory 52 of FIG. Has been changed from K1 to K2 (in step S11), and the long-term memory release unit 133, as shown in the memory 53 of FIG. 5, determines the memory area ( The memory area numbers A7, A8) are set in an unused state. Then, the lost long-time memory detection unit 132 moves the unused memory area to the short-time memory area S (Step S13), and ends the processing. Thereby, the memory area is redistributed into the short-time memory area S and the long-time memory area L.
[0067]
On the other hand, when the memory size comparing unit 131 determines that the memory size of the long-term memory is not reduced (N in step S12), as shown in the memory 54 of FIG. This means that the boundary with the region L has been changed from K1 to K3 (in step S11).
[0068]
Subsequently, as shown by the memory 55 in FIG. 5, the short-time memory release unit 134 sets the time at which the frame was stored in the memory area of the short-time memory in the chronological order (the memory area numbers A6, A5, and A4). Leave unused. This unused memory area is determined by the disappearance short-time memory detection unit 150.
[0069]
Then, the lost short-time memory detection unit 150 moves the unused memory area to the long-time memory area L, and ends the process (step S14). Thereby, the memory area is redistributed into the short-time memory area S and the long-time memory area L.
[0070]
In the above processing, the area of the short-term memory and the long-term memory (the short-term memory area S and the long-term memory area L) are determined by the boundary K2 or K3 when the memory size is changed (step S11). Thus, it is not determined which of the long-term memory and the short-term memory is to be transferred to the other memory.
[0071]
Next, the operation in the third case will be described with reference to the flowchart in FIG. 6 and the state change diagram in FIG. Third, when the storage capacity of the long-term memory and the short-term memory is redistributed, if the memory area of the long-term memory decreases, the reduced memory area is placed in an unused state, and the memory size of each memory is reduced. In the case where the memory area is changed and the memory area of the long-time memory increases, the memory size of each memory is first changed, and then the memory area to be reduced is set to an unused state and transferred to the other memory.
[0072]
The state of the memory 71 in FIG. 7 is the same as the state of the memory 31 in FIG.
First, the flow chart of FIG. 6 is different from that of FIG. 2, that is, the processing after the determination processing (step S2) of whether to reduce the memory area of the long-time memory will be described.
[0073]
When the memory size comparison unit 131 determines that the memory area of the long-term memory is to be reduced (Y in step S2), the long-term memory release unit 133 determines the long-term memory by the lost long-term memory detection unit 132 The used memory area is set in an unused state (step S21).
That is, the state of the memory 72 in FIG. 7 is set, and the memory areas of the memory area numbers A7 and A8 are unused.
[0074]
Subsequently, the lost long-term memory detection unit 132 changes the boundary between the short-term memory area S and the long-term memory area L from K1 to K2 as shown in the memory 73 in FIG. Is moved to the short-term memory area S (step S22), and the process is terminated. That is, the storage capacities of the long-term memory and the short-term memory are redistributed.
[0075]
On the other hand, when the memory size comparison unit 131 determines that the memory area of the long-term memory is not reduced (N in step S2), the lost short-time memory detection unit 150 reduces the number of memory areas of the short-term memory. The size is changed (step S23). The state shown in the memory 74 of FIG. 7 is a state in which the size has been changed, and the boundary between the short-term memory area S and the long-term memory area L has been changed from K1 to K3.
[0076]
Next, as shown by the memory 75 in FIG. 7, the short-time memory release unit 134 sets the time at which the frame was stored in the memory area of the short-time memory in the chronological order (the memory area numbers A6, A5, and A4). Leave unused. This unused memory area is determined by the disappearance short-time memory detection unit 150. Then, the lost short-time memory detection unit 150 moves the unused memory area in the short-time memory area S to the long-time memory area L (Step S24), and ends the processing.
[0077]
Also in the above processing, at the time when the memory size is changed (step S23), only the short-time memory and the long-time memory are determined by the boundary K3. It is in a state where it is not determined whether to move to the time memory area L. That is, when the memory size is changed, the memory areas of the memory area numbers A4, A5, and A6 belong to the short-time memory.
[0078]
Further, the operation in the fourth case will be described with reference to the flowchart in FIG. 8 and the diagram showing the state change in FIG. Fourth, when redistributing the storage capacities of the long-term memory and the short-term memory, if the memory area of the long-term memory decreases, first change the memory size of each memory, and then reduce the memory area. When the memory area of the memory is increased for a long time while the memory area of the memory is increased for a long time, the memory area of the decreasing memory area is changed to the unused state, and then the memory size of each memory is changed.
[0079]
The memory 91 in FIG. 9 is in the same state as the memory 31 in FIG.
First, the flow chart of FIG. 8 is different from that of FIG. 2, that is, the processing after the determination processing (step S2) of whether to reduce the memory area of the long-time memory will be described.
[0080]
When the memory size comparison unit 131 determines that the memory area of the long-term memory is to be reduced (Y in step S2), the lost long-term memory detection unit 132 changes the memory size so as to reduce the number of memory areas of the long-term memory. (Step S31).
The state shown in the memory 92 of FIG. 9 is a state in which the size has been changed, and the boundary between the short-term memory area S and the long-term memory area L has been changed from K1 to K2.
[0081]
Subsequently, the long-time memory release unit 133 sets the memory areas (memory area numbers A7 and A8) of the long-term memory determined by the lost long-term memory detection unit 132 to an unused state, as indicated by the memory 93 in FIG. I do. Then, the lost long-time memory detection unit 132 moves the unused memory area to the short-time memory area S (Step S32), and ends the processing.
[0082]
In the above processing, when the memory size is changed (step S31), the area of the short-time memory and the long-time memory is determined by the boundary K2. Whether to move to the area L is not determined. That is, when the memory size is changed, the memories of the memory area numbers A7 and A8 are long-time memories.
[0083]
On the other hand, when the memory size comparison unit 131 determines that the memory area of the long-term memory is not reduced (N in step S2), the short-time memory release unit 134 determines the memory area determined by the lost short-time memory detection unit 150. Is set to an unused state (step S33). At this time, as shown in the memory 94 of FIG. 9, three memory areas in the short-time memory area are unused in the order of older stored times (the order of the memory area numbers A6, A5, and A4). It becomes.
[0084]
Subsequently, the lost short-time memory detecting unit 150 changes the memory size so that the unused memory area of the short-time memory is used as the long-time memory (step S34), and ends the process. The state in which the size of the memory is changed is the state of the memory 95 in FIG. 9, and the boundary between the long-term memory area L and the short-term memory area S is changed from K1 to K3.
[0085]
Note that the memories described with reference to FIGS. 3, 5, 7, and 9 logically show that the ratio between the short-term memory area and the long-term memory area changes. It need not be physically contiguous.
As described above, an image encoding device can be realized.
[0086]
As described above, according to the present embodiment, when the memory area of the short-term memory is changed to the memory area of the other long-term memory, the memory area stored at the old time of the short-term memory is changed. In an apparatus that encodes an input image while comparing it with a frame to make it more unused, encoding can be performed while comparing the input image with a new frame that is more likely to be a reference. In addition, it is possible to avoid a mismatch between the encoding process and the decoding process.
[0087]
(Embodiment 2)
FIG. 10 is a block diagram of an image decoding apparatus according to the present invention, and decodes an encoded signal str encoded by the image encoding apparatus shown in FIG.
10, the same components as those of the image decoding device shown in FIGS. 1 and 12 are denoted by the same reference numerals, and the description thereof will be described.
[0088]
10, the image decoding apparatus includes a variable length decoding unit 120, a frame memory 102, a motion compensation unit 103, an inverse quantization unit 107, an inverse orthogonal transform unit 108, an addition unit 109, and a management information decoding unit. Conversion unit 236, long-time memory size holding unit 130, memory size comparison unit 131, lost long-term memory detection unit 132, long-time memory release unit 133, lost short-time memory detection unit 150, short-time memory It is composed of an opening unit 134 and a long-time memory moving unit 135, and decodes the input encoded signal str to output a decoded image Vout.
[0089]
As described with reference to FIG. 21, the variable length decoding unit 120 decodes the encoded signal str, outputs the motion vector MV and the reference image number Idx to the frame memory 102, and outputs the quantization value M6 to the inverse quantization unit 107. And outputs the management information MMCO to the management information decoding unit 236.
Further, the quantized value M6 is input to the adding unit 109 as a decoded residual image M8 via the inverse quantization unit 107 and the inverse orthogonal transform unit 108.
[0090]
The motion compensation unit 103 reads out the pixels in the area indicated by the reference image number Idx and the motion vector MV from the frame memory 102 as the motion compensation reference image M2, performs a predetermined operation, calculates the motion compensation image M3, and Output to 109.
The addition unit 109 outputs the decoded image Vout by adding the decoded residual image M8 and the motion compensation image M3, and outputs the decoded image Vout to the frame memory 102 for reference in decoding a subsequent image.
[0091]
Further, the management information decoding unit 236 acquires and decodes the management information MMCO from the variable length decoding unit 120, and transmits the long-term memory size change signal LTS to the frame memory 102, the long-term memory size holding unit 130, the memory size comparing unit 131, and outputs a long-term memory movement signal LTM to the long-time memory movement unit 135. Further, the management information decoding unit 236 outputs the long-time memory release signal LTD to the long-time memory release unit 133 and outputs the short-time memory release signal STD to the short-time memory release unit 134.
[0092]
The operation of setting the memory areas of the short-term memory and the long-term memory to the unused state and changing the respective memory areas is the same as that of the image encoding apparatus of FIG.
With the above configuration, the encoded signal str encoded by the image encoding device in FIG. 10 can be correctly decoded.
[0093]
As described above, according to the present embodiment, when the memory area of the short-time memory is changed to the memory area of the other long-time memory when the memory area of the In an apparatus that decodes an input image while comparing it with a frame in order to make it unused from the area, it is possible to perform decoding while comparing the input image with a new frame that is more likely to be a reference It is possible to avoid a mismatch between the encoding process and the decoding process.
Note that, in each of the above-described embodiments, the process of “releasing the memory area” may be accompanied by a process of deleting the contents of the memory area.
[0094]
Further, the image encoding device and the image decoding device described in the above embodiments can be realized not only by dedicated hardware such as an LSI, but also as a program to be executed by a general-purpose computer such as a personal computer. You can also.
Such a program can be distributed via a recording medium such as a CD-ROM or a transmission medium such as the Internet.
[0095]
FIG. 11 illustrates a case where the image encoding method used in the image encoding device according to the above embodiment and the image decoding method used in the image decoding device are implemented by a computer system using a program stored in a flexible disk. FIG.
[0096]
FIG. 11B shows the appearance, cross-sectional structure, and flexible disk of the flexible disk as viewed from the front, and FIG. 11A shows an example of the physical format of the flexible disk which is a recording medium body. The flexible disk FD is built in the case F, and a plurality of tracks Tr are formed concentrically from the outer circumference toward the inner circumference on the surface of the disk, and each track is divided into 16 sectors Se in an angular direction. ing. Therefore, in the flexible disk storing the program, an image encoding method and an image decoding method as the program are recorded in an area allocated on the flexible disk FD.
[0097]
FIG. 11C shows a configuration for recording and reproducing the program on the flexible disk FD. When the above program is recorded on the flexible disk FD, the image encoding method and the image decoding method as the above program are written from the computer system Cs via the flexible disk drive FDD. When the image encoding method and the image decoding method are constructed in a computer system using a program in a flexible disk, the program is read from the flexible disk by a flexible disk drive and transferred to the computer system.
[0098]
In the above description, the description has been made using a flexible disk as a recording medium. However, the same description can be made using an optical disk. Further, the recording medium is not limited to this, and can be similarly implemented as long as the program can be recorded, such as a CD-ROM, a memory card, a ROM cassette, and the like.
[0099]
As described above, in the present embodiment, with regard to the long-term memory, which part of the memory area is allocated to the long-term memory is determined in advance, and an index that can uniquely designate each memory is determined. When the size of the increase or decrease of the long-term memory is explicitly changed, the following processing is performed.
When the long-term memory decreases, for example, the long-term memory is allocated to the short-term memory in order from a region having a larger index. Note that the regions may be allocated to the memory for a short time in order from the region with the smallest index.
On the other hand, for the short-term memory, the use of the memory area is usually determined by the FIFO. When the long-term memory increases, first, the unused memory among the short-term memory is first used. To be assigned to
[0100]
Further, here, an application example of the image encoding device or the image decoding device described in the above embodiment and a system using the same will be described.
FIG. 12 is a block diagram illustrating an overall configuration of a content supply system ex100 that realizes a content distribution service. A communication service providing area is divided into desired sizes, and base stations ex107 to ex110, which are fixed wireless stations, are installed in each cell.
[0101]
The content supply system ex100 includes, for example, a computer ex111, a PDA (personal digital assistant) ex112, a camera ex113, a mobile phone ex114, and a camera on the Internet ex101 via an Internet service provider ex102 and a telephone network ex104, and base stations ex107 to ex110. Each device such as the mobile phone ex115 is connected.
[0102]
However, the content supply system ex100 is not limited to the combination as shown in FIG. 1, and may be connected by combining any of them. Further, each device may be directly connected to the telephone network ex104 without going through the base stations ex107 to ex110 which are fixed wireless stations.
[0103]
The camera ex113 is a device such as a digital video camera capable of shooting moving images. In addition, a mobile phone can be a PDC (Personal Digital Communications) system, a CDMA (Code Division Multiple Access) system, a W-CDMA (Wideband-Code Division Multiple Access mobile phone system, or a GSM gigabit mobile access system). Or PHS (Personal Handyphone System) or the like.
[0104]
The streaming server ex103 is connected from the camera ex113 to the base station ex109 and the telephone network ex104, and enables live distribution and the like based on encoded data transmitted by the user using the camera ex113. The encoding process of the photographed data may be performed by the camera ex113, or may be performed by a server or the like that performs the data transmission process.
[0105]
Also, moving image data captured by the camera 116 may be transmitted to the streaming server ex103 via the computer ex111. The camera ex116 is a device such as a digital camera that can shoot still images and moving images. In this case, encoding of the moving image data may be performed by the camera ex116 or the computer ex111. The encoding process is performed by the LSI ex117 of the computer ex111 and the camera ex116.
[0106]
The image encoding / decoding software may be incorporated in any storage medium (CD-ROM, flexible disk, hard disk, or the like) that is a recording medium readable by the computer ex111 or the like. Further, the moving image data may be transmitted by the mobile phone with camera ex115. The moving image data at this time is data encoded by the LSI included in the mobile phone ex115.
[0107]
In the content supply system ex100, the content (for example, a video image of a live music) captured by the user with the camera ex113, the camera ex116, or the like is encoded and transmitted to the streaming server ex103 as in the above-described embodiment. On the other hand, the streaming server ex103 stream-distributes the content data to the requesting client.
[0108]
Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, and the like that can decode the encoded data. In this way, the content supply system ex100 can receive and reproduce the encoded data at the client, and further, realizes personal broadcast by receiving, decoding, and reproducing the data in real time at the client. It is a system that becomes possible.
[0109]
The encoding and decoding of each device constituting this system may be performed using the image encoding device or the image decoding device described in each of the above embodiments.
A mobile phone will be described as an example.
[0110]
FIG. 13 is a diagram illustrating a mobile phone ex115 that uses the image encoding device and the image decoding device described in the above embodiment. The mobile phone ex115 includes an antenna ex201 for transmitting and receiving radio waves to and from the base station ex110, a camera unit ex203 capable of taking a picture such as a CCD camera, a still image, a picture taken by the camera unit ex203, and an antenna ex201. A display unit ex202 such as a liquid crystal display for displaying data obtained by decoding a received video or the like, a main unit including a group of operation keys ex204, an audio output unit ex208 such as a speaker for outputting audio, and audio input. Input unit ex205 such as a microphone for storing encoded or decoded data, such as data of captured moving images or still images, received mail data, moving image data or still image data, etc. Storage media ex207, attached storage media ex207 to mobile phone ex115 And a slot portion ex206 to ability. The storage medium ex207 stores a flash memory element, which is a kind of an electrically erasable and programmable read only memory (EEPROM), which is a nonvolatile memory that can be electrically rewritten and erased, in a plastic case such as an SD card.
[0111]
Further, the mobile phone ex115 will be described with reference to FIG. The mobile phone ex115 is provided with a power supply circuit unit ex310, an operation input control unit ex304, an image encoding unit, and a main control unit ex311 which controls the respective units of a main body unit including a display unit ex202 and operation keys ex204. Unit ex312, camera interface unit ex303, LCD (Liquid Crystal Display) control unit ex302, image decoding unit ex309, demultiplexing unit ex308, recording / reproducing unit ex307, modulation / demodulation circuit unit ex306, and audio processing unit ex305 via the synchronous bus ex313. Connected to each other.
[0112]
When the end of the call and the power key are turned on by a user operation, the power supply circuit unit ex310 supplies power to each unit from the battery pack to activate the digital cellular phone with camera ex115 in an operable state. .
[0113]
The mobile phone ex115 converts a sound signal collected by the sound input unit ex205 into digital sound data by the sound processing unit ex305 in the voice call mode based on the control of the main control unit ex311 including a CPU, a ROM, a RAM, and the like. This is spread-spectrum-processed by a modulation / demodulation circuit unit ex306, subjected to digital-analog conversion processing and frequency conversion processing by a transmission / reception circuit unit ex301, and then transmitted via an antenna ex201.
[0114]
Also, the mobile phone ex115 amplifies the received signal received by the antenna ex201 in the voice communication mode, performs frequency conversion processing and analog-to-digital conversion processing, performs spectrum despreading processing in the modulation / demodulation circuit unit ex306, and performs analog voice After being converted into a signal, the signal is output via the audio output unit ex208.
[0115]
Further, when an e-mail is transmitted in the data communication mode, text data of the e-mail input by operating the operation key ex204 of the main body is sent to the main control unit ex311 via the operation input control unit ex304. The main control unit ex311 performs spread spectrum processing on the text data in the modulation / demodulation circuit unit ex306, performs digital / analog conversion processing and frequency conversion processing in the transmission / reception circuit unit ex301, and transmits the data to the base station ex110 via the antenna ex201.
[0116]
When transmitting image data in the data communication mode, the image data captured by the camera unit ex203 is supplied to the image encoding unit ex312 via the camera interface unit ex303. When image data is not transmitted, image data captured by the camera unit ex203 can be directly displayed on the display unit ex202 via the camera interface unit ex303 and the LCD control unit ex302.
[0117]
The image encoding unit ex312 includes the image encoding device described with reference to FIG. 1, and uses the image data supplied from the camera unit ex203 in the encoding method used in the image encoding device described in the above embodiment. The image data is converted into encoded image data by compression encoding, and is transmitted to the demultiplexing unit ex308. At this time, the mobile phone ex115 simultaneously transmits the audio collected by the audio input unit ex205 during imaging by the camera unit ex203 to the demultiplexing unit ex308 as digital audio data via the audio processing unit ex305.
[0118]
The demultiplexing unit ex308 multiplexes the encoded image data supplied from the image encoding unit ex312 and the audio data supplied from the audio processing unit ex305 by a predetermined method, and multiplexes the resulting multiplexed data into a modulation / demodulation circuit unit. The signal is subjected to spread spectrum processing in ex306 and subjected to digital-analog conversion processing and frequency conversion processing in the transmission / reception circuit unit ex301, and then transmitted via the antenna ex201.
[0119]
When receiving data of a moving image file linked to a homepage or the like in the data communication mode, the modulation and demodulation circuit unit ex306 performs spectrum despread processing on a received signal received from the base station ex110 via the antenna ex201, and obtains the resulting multiplexed signal. The demultiplexed data is sent to the demultiplexing unit ex308.
[0120]
To decode the multiplexed data received via the antenna ex201, the demultiplexing unit ex308 separates the multiplexed data into coded image data and audio data by separating the multiplexed data, and transmits the multiplexed data via the synchronization bus ex313. And supplies the encoded image data to the image decoding unit ex309 and the audio data to the audio processing unit ex305.
[0121]
Next, the image decoding unit ex309 is configured to include the image decoding device described with reference to FIG. 10 and decodes the encoded image data using a decoding method corresponding to the encoding method described in the above embodiment. Thereby, reproduced moving image data is generated and supplied to the display unit ex202 via the LCD control unit ex302, whereby, for example, moving image data included in a moving image file linked to a homepage is displayed. At this time, the audio processing unit ex305 simultaneously converts the audio data into an analog audio signal, and supplies the analog audio signal to the audio output unit ex208. Thereby, the audio data included in the moving image file linked to the homepage is reproduced, for example. You.
[0122]
It should be noted that the present invention is not limited to the example of the system described above, and digital broadcasting using satellites and terrestrial waves has recently become a hot topic. As shown in FIG. Any of the decoding devices can be incorporated.
[0123]
Specifically, at the broadcasting station ex409, an encoded bit stream of video information is transmitted to a communication or broadcasting satellite ex410 via radio waves. The broadcasting satellite ex410 receiving this transmits a radio wave for broadcasting, receives this radio wave with a home antenna ex406 having a satellite broadcasting receiving facility, and transmits the radio wave to a television (receiver) ex401 or a set-top box (STB) ex407 or the like. The device decodes the encoded bit stream and reproduces it. Further, the image decoding device described in the above embodiment can also be mounted on a playback device ex403 that reads and decodes an encoded bit stream recorded on a storage medium ex402 that is a recording medium.
[0124]
In this case, the reproduced video signal is displayed on the monitor ex404. A configuration is also conceivable in which an image decoding device is mounted in a set-top box ex407 connected to a cable ex405 for cable television or an antenna ex406 for satellite / terrestrial broadcasting, and this is reproduced on a monitor ex408 of the television.
[0125]
At this time, the image encoding device may be incorporated in the television instead of the set-top box. Further, it is also possible to receive a signal from the satellite ex410 or the base station ex107 or the like with the car ex412 having the antenna ex411 and reproduce the moving image on a display device such as the car navigation ex413 or the like included in the car ex412.
[0126]
The configuration of the car navigation system ex413 may be, for example, a configuration excluding the camera unit ex203 and the camera interface unit ex303 in the configuration illustrated in FIG. 14. . In addition, terminals such as the mobile phone ex114 and the like have three mounting formats, in addition to a transmitting / receiving terminal having both an encoder and a decoder, a transmitting terminal having only an encoder and a receiving terminal having only a decoder. Can be considered.
[0127]
As described above, it is possible to use the image encoding device and the image decoding device shown in the embodiment of FIGS. 1 and 10 in any of the devices and systems described above. The effect described in 10 can be obtained.
[0128]
【The invention's effect】
As is apparent from the above description, the image encoding apparatus according to the present invention is an apparatus that performs encoding while comparing an input image with a reference image, and has a first storage area and a data storage method that are different from each other. A storage unit that stores the reference image by dividing it into a second storage area; and a storage unit that reduces the storage capacity when the storage capacity of the first and second storage areas is redistributed. A redistribution unit is provided for setting a storage area in which a reference image is stored at an old time as a second storage area having a larger storage capacity.
[0129]
With this, when the storage capacity of the first storage area is reduced, the reference image stored at the old time is lost, so that the input image is compared with a new reference image that is more likely to be referred to. It is possible to perform encoding while avoiding mismatch between the encoding process and the decoding process.
[0130]
A decoding unit that decodes the input image while comparing the input image with the reference image, the storage unit configured to store the reference image by dividing the image into a first storage area and a second storage area having different data read / write schemes; When redistributing the storage capacity of the first and second storage areas, the storage area in which the reference image is stored at the earliest time in the first storage area having the smaller storage capacity is increased. And a redistribution unit for making the storage area usable as a second storage area.
[0131]
With this, when the storage capacity of the first storage area is reduced, the reference image stored at the old time is lost, so that the input image is compared with a new reference image that is more likely to be referred to. Decoding can be performed while avoiding mismatch between the encoding process and the decoding process.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image encoding device according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of the image coding apparatus according to the first embodiment;
FIG. 3 is a diagram showing a state of a memory in the image encoding device according to the first embodiment;
FIG. 4 is a flowchart showing another operation of the image coding apparatus according to the first embodiment;
FIG. 5 is a diagram showing another state of the memory in the image encoding device of the above.
FIG. 6 is a flowchart showing still another operation of the image encoding apparatus.
FIG. 7 is a diagram showing still another state of the memory in the image encoding device of the above.
FIG. 8 is a flowchart showing yet another operation of the above image encoding device.
FIG. 9 is a diagram showing still another state of the memory in the image encoding device of the above.
FIG. 10 is a block diagram illustrating a configuration of an image decoding device according to a second embodiment of the present invention.
FIGS. 11A, 11B, and 11C are explanatory diagrams of a case where the present invention is implemented by a computer system using a flexible disk storing an image encoding method and an image decoding method according to the present invention.
FIG. 12 is a configuration diagram showing an overall configuration of a content supply system using an image encoding device and an image decoding device according to the present invention.
FIG. 13 is an external view showing a configuration of a mobile phone using the image encoding device and the image decoding device according to the present invention.
FIG. 14 is a block diagram showing a configuration of the mobile phone of the above.
FIG. 15 is a configuration diagram illustrating an overall configuration of a digital broadcasting system using the image encoding device and the image decoding device according to the present invention.
FIG. 16 is a block diagram illustrating a configuration of an image encoding device assumed from a conventional image encoding method and the like.
17A and 17B are explanatory diagrams of an image management method.
FIGS. 18A and 18B are explanatory diagrams of image encoding using a short-time memory.
FIG. 19 is an explanatory diagram of image encoding using a long-term memory.
FIGS. 20A and 20B are explanatory diagrams of an image management method.
FIG. 21 is a block diagram illustrating a configuration of an image decoding device assumed from a conventional image decoding method.
[Explanation of symbols]
101 Motion detector
102 frame memory
103 Motion compensation unit
104 Subtraction unit
105 orthogonal transform unit
106 Quantization unit
107 Inverse quantization unit
108 Inverse orthogonal transform unit
109 Adder
110 variable length coding unit
130 Long-time memory size holding unit
131 Memory size comparison unit
132 Lost long time memory detector
133 Long-time memory release section
134 Short-time memory release section
135 Long-term memory moving unit
136 management information encoding unit
150 erasure short-time memory detector

Claims (12)

An apparatus for encoding while comparing an input image with a reference image,
Storage means for storing a reference image by dividing into a first storage area and a second storage area having different data read / write methods;
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. An image encoding device, comprising: a reallocation unit that makes the image data usable as a second storage area. The redistribution unit sets a storage area in which a reference image is stored at the oldest time in the first storage area to an unused state, and adds the unused storage area to the second storage area. The image coding apparatus according to claim 1, wherein The first storage area is a first-in first-out storage area,
The image encoding device according to claim 1, wherein the second storage area is a storage area of a random access method. The first storage area is a short-term storage memory,
The image according to any one of claims 1 to 3, wherein the second storage area is a long-term storage memory that stores a reference image for a longer time than the first storage area. Encoding device. An apparatus for decoding while comparing an input image with a reference image,
Storage means for storing a reference image by dividing into a first storage area and a second storage area having different data read / write methods;
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. An image decoding device, comprising: a reallocation unit that sets a state in which the image data can be used as a second storage area. The redistribution unit sets a storage area in which a reference image is stored at the oldest time in the first storage area to an unused state, and adds the unused storage area to the second storage area. The image decoding apparatus according to claim 5, wherein The first storage area is a first-in first-out storage area,
7. The image decoding apparatus according to claim 5, wherein the second storage area is a storage area of a random access method. The first storage area is a short-term storage memory,
The image according to any one of claims 5 to 7, wherein the second storage area is a long-term storage memory that stores a reference image for a longer time than the first storage area. Decryption device. An image encoding method using a storage unit that stores a reference image by dividing into a first storage area and a second storage area having different data read / write methods,
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. An image coding method, wherein the image is set to be usable as a second storage area. An image decoding method using a storage unit that stores a reference image by dividing into a first storage area and a second storage area having different data read / write methods,
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. An image decoding method, wherein the image is set to be usable as a second storage area. A program for image encoding using a storage unit that stores a reference image by dividing into a first storage area and a second storage area having different data read / write methods,
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. A program for causing a computer to execute a step of making the storage area usable as a second storage area. A program for image decoding using a storage unit that stores a reference image by dividing into a first storage area and a second storage area having different data read / write methods,
When the storage capacity of the first and second storage areas is redistributed, the storage area in which the reference image is stored at the oldest time in the first storage area having the smaller storage capacity has a larger storage capacity. A program for causing a computer to execute a step of making the storage area usable as a second storage area.

Images