JP6740549B2 - Moving picture coding apparatus, method, program, and moving picture coding system - Google Patents

Description

The present invention relates to a moving picture coding device, method, program, and moving picture coding system.

As a method of compressing a moving image, there is known a method of encoding the moving image by utilizing the similarity between a plurality of frames forming the moving image (each still image forming the moving image). In this method, for example, by calculating a difference between a still image serving as a reference (hereinafter, referred to as an encoding target image) and a still image (hereinafter, referred to as a reference image) before or after (past or future) Encode the moving image. Generally, when encoding a moving image, each still image is divided into a plurality of regions in block units, and the similarity between the encoding target image and the reference image is compared with pixel data in each block unit. Generate a predicted image with.

A method for encoding a moving image will be described with reference to FIG. FIG. 10 is a conceptual diagram for explaining a method for encoding a moving image, FIG. 10( a) shows a method for encoding a moving image without using a reference image, and FIG. 10( b) is a reference image. 2 shows a method of encoding a moving image using.

In FIG. 10A, consider a case where a block 11 surrounded by a square in the center of the encoding target image 10 (hereinafter referred to as an encoding target block) is encoded. If the encoding target block 11 is encoded as it is, the code amount becomes large.

On the other hand, as shown in FIG. 10B, consider a method of encoding the encoding target block 11 using the reference image 12. In this case, first, the frames before and after the encoding target image 10 are defined as the reference image 12, and a block of pixel data similar to the encoding target block 11 (hereinafter, referred to as a prediction target block) is searched from within the reference image (hereinafter, referred to as a prediction target block). , Called motion search). Then, the prediction image 13 including the prediction target block 14 is generated based on the search result of the motion search.

Next, the encoding target image is encoded based on the difference value between the prediction target block 14 and the encoding target block 11. At this time, the final code amount is a value obtained by adding the difference value between the predicted image and the reference image to the motion vector indicating the position of the reference image.

Since the difference between the target image to be encoded and the predicted image similar to the target image to be encoded is small, the method of encoding using the reference image has a larger code amount than the case of encoding without using the reference image. Is small.

However, the method of coding a moving image using a reference image needs to perform a motion search for the entire range of the reference image. Since it takes time to perform the motion search for the entire range of the reference image, it is difficult to encode the moving image using the reference image in an encoder, a hardware encoder, etc. that needs to be encoded at high speed. Is. For this reason, a method of limiting the range that a motion vector can take is being studied for motion search. Below, the range which this motion vector can take is called a search permission range. Also, in order to search only the range in which there is a high possibility that there is a similarity with the target block, instead of searching the entire search permitted range, the search is limited to a certain range from the center of the search permitted range. Methods to do so are also being considered. Below, the range in which the motion search is actually executed is called the search range.

The moving picture coding apparatus described in Patent Document 1 determines the center of motion search by determining the degree of similarity between peripheral images in the same frame as the coded image, and optimizes the search range of motion vectors. ..

The motion search described in Non-Patent Document 1 limits the search range of the motion vector by selecting and deriving the center of the motion search from a plurality of candidates.

JP, 2006-166247, A

L.-F. Ding, W.-Y. Chen, P.-K. Tsung, T.-D. Chuang, P.-H. Hsiao, Y.-H. Chen, H.-K. Chiu, S .-Y. Chien, and L.-G. Chen, “A 212 Mpixels/s 4096x2160p multiview video encoder chip for 3D/quad full HDTV applications,” IEEE Journal of Solid-State Circuits, vol. 45, no. 1, pp. 46-58, Jan. 2010.

When encoding a moving image with a large screen size such as Full HD (High Definition Video), 4K, 8K, even if a method of limiting the search range of the motion search from the search center to a certain range is used, The reference location differs depending on the block. Therefore, in order to encode a moving image at high speed, it is necessary to store image data in the search range inside the device. However, when the search permission range is large, the amount of information becomes enormous, and it is difficult to install a storage device capable of storing all the image data in the search permission range inside. Therefore, when the image data is large, the image data is usually stored in the external storage device. Here, the external storage device is, for example, in the case of a hardware encoder, an SDRAM (Synchronous Dynamic Random Access Memory) or the like installed outside the encoder core. However, when the image data is stored in the external storage device, the external storage device has a large access delay and it takes time to read the image data, so that there is a problem that a delay occurs in encoding.

Patent Document 1 includes a coded image memory that outputs a coded image and a reference image memory that outputs a reference image. Therefore, in Patent Document 1, when the screen size becomes large, it is necessary to store the image data required for encoding in the external storage device, and therefore, encoding may be delayed.

In Non-Patent Document 1, although a method is adopted in which all data is not retained by the cache mechanism, the cache mechanism becomes complicated, and the hardware encoder increases the circuit scale and causes a delay when no cache hit occurs. there is a possibility.

An object of the present invention is to provide a moving picture coding apparatus, method, program, and moving picture coding system that does not require a cache mechanism for holding a moving picture when coding a moving picture and that does not cause delay. To do.

A moving image encoding device according to one aspect of the present invention reads image data in a predetermined area of a reference image corresponding to an encoding target image from an external storage device that holds a plurality of still images that form a moving image, a reference image reading unit to be stored in the internal buffer, using the image data of a predetermined region of the reference image stored in the internal buffer, the encoding target area of the target image for encoding, the coding target A motion search is executed for a first search range centered on a vector of a region adjacent to the region and a second search range centered on a zero vector of the encoding target region , and search results are respectively set to the first and second search results . And a vector search unit for generating a motion vector having the best evaluation function value. The vector search unit compares the evaluation function values of the first and second motion vectors and selects the motion vector with the best evaluation function value. Then, output as an evaluation motion vector, the reference image reading unit, from the external storage device, the previous search range corresponding to the evaluation motion vector previously output by the vector search unit and the vector search unit next time. With respect to the next search range corresponding to the motion vector for performing the motion search, the image data is read out by using the area obtained by at least doubling the vertical and horizontal directions of the search range as the predetermined area, and then reading the image data into the internal buffer. Store.

In a moving image coding method according to another aspect of the present invention, a reference image reading unit is configured to detect a predetermined area of a reference image corresponding to a coding target image from an external storage device that holds a plurality of still images forming a moving image. Of the image data of the reference image is stored in the internal buffer, and the vector search unit uses the image data of the predetermined region of the reference image stored in the internal buffer as the encoding target region of the encoding target image. On the other hand, the motion search is executed for the first search range centered on the vector of the region adjacent to the coding target region and the second search range centered on the zero vector of the coding target region, and the search result As the first and second motion vectors, respectively, and the vector search unit compares the evaluation function values of the first and second motion vectors and selects the motion vector with the best evaluation function value. Then, output as an evaluation motion vector, the reference image reading unit, from the external storage device, the previous search range corresponding to the evaluation motion vector previously output by the vector search unit and the vector search unit next time. With respect to the next search range corresponding to the motion vector for performing the motion search, the image data is read out by using the area obtained by at least doubling the vertical and horizontal directions of the search range as the predetermined area, and then reading the image data into the internal buffer. Store.

According to another aspect of the present invention, there is provided a moving image encoding program, which causes a computer to extract image data of a predetermined area of a reference image corresponding to an encoding target image from an external storage device that holds a plurality of still images forming a moving image. For the encoding target area of the encoding target image by using reference image reading means for reading and storing the image in a predetermined area of the reference image stored in the internal buffer, A motion search is executed for a first search range centered on a vector of a region adjacent to the coding target region and a second search range centered on a zero vector of the coding target region, and the search results are respectively set to the first search range . A moving picture coding program that functions as a vector search means for generating the first and second motion vectors, the vector search means comparing the evaluation function values of the first and second motion vectors. Then, the motion vector having the best evaluation function value is selected and output as an evaluation motion vector, and the reference image reading unit, from the external storage device, to the evaluation motion vector previously output by the vector searching unit. the relative and next search range corresponding to the motion vector corresponding previous search range and the vector search unit performs the motion search to the next, at least twice the area of the vertical and horizontal their search range prescribed The image data is read out as the area of and stored in the internal buffer.

According to another aspect of the present invention, there is provided a moving image coding system, comprising: an external storage device that holds a plurality of still images that form a moving image; and a predetermined area of a reference image corresponding to the encoding target image from the external storage device. A reference image reading unit that reads out image data and stores the image data in an internal buffer, and image data of a predetermined region of the reference image stored in the internal buffer, is used for an encoding target region of the encoding target image. Then, a motion search is executed for a first search range centered on a vector of a region adjacent to the coding target region and a second search range centered on a zero vector of the coding target region, and a search result is obtained. And a vector search unit that generates a first motion vector and a second motion vector, respectively. The vector search unit compares evaluation function values of the first and second motion vectors, and the evaluation function value is the highest. Selecting a good motion vector and outputting it as an evaluation motion vector, the reference image reading unit, from the external storage device, the previous search range corresponding to the evaluation motion vector previously output by the vector searching unit and the The vector search unit reads the image data with a region obtained by at least doubling the vertical and horizontal directions of the next search range corresponding to the motion vector for which the motion search is performed next time as the predetermined region. However, it is stored in the internal buffer.

According to the present invention, a moving picture coding apparatus, method, program, and moving picture coding system that do not require a cache mechanism for holding a moving picture when a moving picture is coded and do not cause a delay are provided. can do.

It is a block diagram which shows the structure of the moving image encoding apparatus which concerns on the 1st Embodiment of this invention. It is a conceptual diagram for demonstrating the concept of the motion vector which concerns on this invention. It is a schematic diagram for demonstrating operation|movement of the moving image encoding apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the search range of the motion search which concerns on this invention. It is a flowchart which shows the flow of operation|movement of the moving image encoding apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the moving image encoding apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the flow of operation|movement of the moving image encoding apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the moving image encoding system which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the information processing apparatus which comprises the moving image encoding apparatus which concerns on this invention. 3A and 3B are conceptual diagrams for explaining a method of encoding a moving image, in which (a) shows a method of encoding a moving image without using a reference image, and (b) shows an example of encoding a moving image using a reference image. Shows how to make it.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in order to avoid complication due to repetitive description, the same or corresponding portions in each drawing are denoted by the same reference numerals, and description thereof will be appropriately omitted.

[First Embodiment]
[Video Coding Device]
A moving image encoding apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG.

The moving image coding apparatus 100 includes a reference image reading unit 110 and a vector searching unit 120.

The reference image reading unit 110 reads a reference image of an encoding target image from an external storage device (not shown) that holds a moving image composed of a plurality of still images (frames). The reference image means a past or future still image with respect to the encoding target image. The reference image reading unit 110 also stores the reference image read from the external storage device in the internal buffer. Here, the internal buffer may be included in the reference image reading unit 110, or may be included in the moving image encoding device 100 independently of the reference image reading unit 110.

The vector search unit 120 performs a motion search in an arbitrary search range for the coding target area of the coding target image based on the coding target image and the reference image stored in the internal buffer, and moves the search result as a motion. Generate as a vector. Here, the vector search unit 120 may specify the center of the search range by position coordinates or a vector from the encoding target area. Further, the vector search unit 120 executes motion search for each search range when N (N is an integer of 2 or more) search ranges having different arbitrary ranges are set as the first to Nth search ranges. Then, the search result is generated as the first to Nth motion vectors. Further, the vector search unit 120 compares the evaluation function values of the first to Nth motion vectors, selects one motion vector having the best evaluation function value, and outputs it as an evaluation motion vector.

Here, as the evaluation function value, for example, SAD (Sum of Absolute Difference) that searches for a point having a high similarity between the encoding target image and the reference image can be used. In this case, the best motion vector means the motion vector having the smallest SAD value. The method of comparing the evaluation function values is not limited to the above, and any evaluation method that can compare the encoding target image 20 and the reference image 30 may be used.

[Concept of motion vector]
The concept of the motion vector generated by the moving image coding apparatus 100 will be described with reference to FIG. FIG. 2 shows an image 20 to be encoded and a reference image 30.

The encoding target image 20 is an arbitrary still image that serves as a reference when encoding a moving image among a plurality of still images forming the moving image. In FIG. 2, the encoding target image 20 includes an encoding target block 21. The encoding target block 21 is an area to be encoded in the encoding target image 20.

The reference image 30 is a still image that is one frame past (or future) with respect to the encoding target image 20 among a plurality of still images that form a moving image. The search range 31 is a range within the reference image 30 in which the moving picture coding apparatus 100 performs a motion search. The search range 31 is not particularly limited, but is preferably in the vicinity of the encoding target block 21. This is because when the reference image 30 is a still image that is one frame past the encoding target image 20, the position of the encoding target block 21 is likely not to change significantly. Further, by setting the range to perform motion search between zero vector of the encoding target block 21, the reference image 30 may perform motion search at the same position as the coding pairs Zobu lock 21. The prediction target block 32 is an area most similar to the coding target block 21 in the search range 31. That is, the moving picture coding apparatus 100 searches for the position of the prediction target block 32 by searching within the search range 31.

The motion vector 40 indicates the motion of the coding target block 21 with respect to the prediction target block 32. In FIG. 2, only the motion vector 40 is shown as the motion vector, but the moving picture coding apparatus 100 can generate a plurality of motion vectors by setting a plurality of ranges in which the motion search is executed.

[Operation of video encoding device]
A specific example of the operation of the moving picture coding apparatus 100 will be described with reference to FIG. FIG. 3 shows an encoding target image 20′ having a plurality of regions and a reference image 30′.

As shown in FIG. 3, the encoding target image 20 ′ includes a total of 12 areas of blocks 1 to 12 of 4 horizontal blocks×3 vertical blocks. The reference image 30' includes a total of 12 regions of blocks 1'to 12'. Here, the positions of the blocks 1'to 12' correspond to the positions of the blocks 1 to 12, respectively.

In order to generate the motion vector of the coding target block among the blocks 1 to 12, it is effective to execute the motion search with a block near the coding target block as the search range. For example, when the block to be coded is block 2, when the motion vector of block 2 is generated, as the neighboring block (adjacent block), for example, the vector (position) of block 1′ adjacent to the left It is effective to execute the motion search with the range centered at as the search range. In this case, the moving picture coding apparatus 100 reads the block 1'as the search range from the external storage device in the reference image 30' and executes the motion search. In addition, when the motion vector cannot be generated in the motion search of the block 1′, the moving picture coding apparatus 100 horizontally moves to the block 2′, the block 3′, and the block 4′ after the end of the search of the block 1′. It is assumed that the motion search is performed on the blocks in one row.

Here, when performing the motion search centering on the vector of the block 1 ′ and performing the motion search for the next block 2, the moving picture decoding apparatus 100 determines that the external storage device is available after the motion search of the block 1 ′ is completed. From this, block 2'is read out as a reference image as a motion search range. Therefore, since the moving picture coding apparatus 100 executes the motion search of the block 2 after reading the reference image from the external storage device, the time until the reference image is read from the external storage device becomes a delay time and the coding efficiency is high. Getting worse. This is the same as when the motion search is performed on the blocks in a horizontal row when the block 6 to be encoded is also subjected to the motion search on the adjacent block 2′. If a delay of 1 occurs, a delay occurs before the motion search is executed.

Therefore, the moving picture coding apparatus 100 according to the first embodiment eliminates the delay time by, for example, pre-reading the information of the motion vector of the neighboring block to the left of the coding target block. Specifically, in the first embodiment, the reference image reading unit 110 uses the result of the motion search performed by the vector search unit 120 of the moving image coding apparatus 100 to eliminate the delay time.

In the following, a method will be described in which the moving picture coding apparatus 100 eliminates delay time by executing a motion search for two search ranges for a block to be coded.

For two of the search range, is not particularly limited, for example, a search range for the vector of a block adjacent to the left of the encoding target block as a contiguous block (position) and the center of the motion search, the vector of a block adjacent to the left Is a search range with different vectors (positions) as the center of motion search . Here, the vector different from the vector of the block adjacent to the left of the encoding target block is not particularly limited, but may be, for example, a zero vector of the encoding target vector. Further, as a vector different from the motion vector of the block adjacent to the left, for example, a motion vector obtained by searching a wide range in advance using a reduced image or an image in which pixels are thinned out may be used.

Note that, for simplicity, a case will be described in which a moving image is encoded based on two motion vectors, but this is an example and does not limit the present invention. The present invention can encode a target image for encoding based on N motion vectors.

First, the reference image reading unit 110 reads the reference image corresponding to the encoding target image from the external storage device and stores it in the internal buffer.

The vector search unit 120 executes a motion search centering on a vector of a block (left adjacent block) adjacent to the left of the target block to be encoded, based on the target image to be encoded and the reference image stored in the internal buffer. The result is generated as the first motion vector. Here, the vector searching unit 120, an evaluation motion vectors will be described later, to generate the motion vector of the left neighboring block is when you perform two types of motion search. Specifically, when a motion search centered on a zero vector is executed in a block adjacent to the left of the encoding target block (left adjacent block), and when the motion vector of the adjacent block to the left of the encoding target block is two. This is when the motion search with the center is executed .

Furthermore, the vector searching unit 120 performs a motion search around the zero vector of the encoding target block, and outputs the search result as a second motion vector. The vector search unit 120 compares the evaluation function value of the first motion vector and the evaluation function value of the second motion vector, and outputs the evaluation motion vector towards the good evaluation function value. Here, the evaluation as the motion vector, for example, it is noted that it may become a motion vector of the two left adjacent block of the encoding target block. Further, the block in the reference image designated by the evaluation motion vector is set as the prediction target block. Further, next, the vector searching unit 120 is different from the search range corresponding to the second motion vector and our first motion vector of the previous corresponding to the first motion vector and the second motion vector new A motion search is performed in the search range, and an evaluation motion vector is generated as a third motion vector.

Reference image reading unit 110, for each of the third motion vector and our evaluation motion vector outputted previously, external stores reference image vertical and horizontal search range in at least twice the area of the vector search unit 120 Read from the device. Then, the reference image reading unit 120 stores the read reference image in the internal buffer.

Next, the vector searching unit 120 searches the position of the prediction target block that is similar to the encoding target block. Here, the vector searching unit 120, as the evaluation motion vector, for example, to produce a motion vector of a block adjacent to the left of the encoding target block (left neighboring blocks), the motion for the two search ranges as described above It is when the search is executed. Therefore, the vector searching unit 120 to search for the position of the prediction target block, and executes the three motion search to be described below.

The first motion search is a motion search centered on the zero vector of the current block (hereinafter referred to as search A). The second motion search is a motion search centered on the motion vector generated by the motion search centered on the zero vector in the block adjacent to the left of the encoding target block (left adjacent block) (hereinafter, search B and Call). Then, the motion estimation of the three eyes, the two left adjacent block motion vectors motion search around the motion vector generated by the motion search around the encoding target block (hereinafter, referred to as the search C) Is.

Reference image reading unit 110, to the search range around zero Robekutoru of the encoding target block, reads the reference image obtained by adding at least vertically and horizontally and twice the area of the search range (hereinafter, a reading A Call). In addition, the reference image reading unit 120 reads a reference image in which a search range is added to the search result (prediction target block) of the search centered on the motion vector of the neighboring block to the left of the coding target block (the prediction target block) ( Hereinafter referred to as read B).

As described above, the vector search unit 120 executes the search C before the read B. That is, the range of the reference image read by the read B is included in the range of the reference image read by the read A. That is, the reference image reading unit 120 can omit the process of reading B by adding an additional area to the motion vector search result of the adjacent block to the left of the encoding target block.

Therefore, the moving picture coding apparatus 100 does not need to read the reference image for the search range of the prediction target block from the external storage device when performing the motion search of the prediction target block, and therefore delays in reading the reference image. It can be resolved.

FIG. 4 is a schematic diagram showing the relationship between the search range in the vector search unit 110 and the area read by the reference image read unit 120. Hereinafter, a method of prefetching the reference image by the reference image reading unit 120 will be specifically described with reference to FIG.

The reference image 50 includes a block 51 adjacent to the block to be coded. Adjacent blocks 51, that could be specified by the motion search around the two preceding vectors proximity block zero vector or the encoding target block, the encoding target block. The search range 52 indicates the search range of the adjacent block 51.

The reference image 60 shows the search result obtained by performing the motion search on the search range 52 in the reference image 50, and includes the prediction target block 53 as the search result . In this example, the prediction target block 53 is located at the lower right of the search range 52.

The reference image 70 is a region in which the search range centered on the zero vector of the target block to be encoded is at least twice the length and width of the search range with respect to the reference image 60, and a search for the prediction target block 53. It includes a region with an added range. Here, the search range 54 is a search range for motion search of the prediction target block 53, and the additional region 55 is a region in which the search range 52 of the adjacent block 51 is doubled vertically and horizontally.

The search range of the search A described above is a search range centered on the zero vector of the block to be coded . That is, the search range of the search A is within the range of the read A because it is included in the search range 52. Further, since the search range of the search B described above is generally the search range of the motion search centered on the motion vector generated by the motion search in the search centered on the zero vector in the immediately preceding neighboring block, corresponds to the search range 52 of adjacent blocks 51 in FIG. 4. That is, the search range of the search B is within the range of the read A, like the search A. Furthermore, the search C described above, generally, since the two previous vectors motion vectors generated by the motion search around the proximity block of the encoding target block motion search around the predicted target 4 Corresponds to block 53. Therefore, the search range of the search C corresponds to the search range 54 of the prediction target block 53 . Here, the search range 54 is within the range of the additional area 55. That is, the search range of the search C is included in the range of the additional area 55 and thus is within the range of the read B.

Therefore, the moving picture coding apparatus 100 reads the reference image including the search range of the prediction target block 53 in advance before reading the reference image of the search range of the prediction target block 53. Therefore, the moving image coding apparatus 100 can omit the time for reading the reference image in the search range of the prediction target block 53, and thus can eliminate the delay in coding the coding target image.

FIG. 5 is a flowchart showing an operation flow of the moving picture coding device 10 according to the first embodiment of the present invention. Hereinafter, with reference to FIG. 5, an operation flow of the moving picture coding apparatus 100 according to the first embodiment of the present invention will be described.

First, the reference image reading unit 110 reads out image data of a predetermined area of the reference image corresponding to the encoding target image from an external storage device that holds a plurality of still images that form a moving image (step S101). Here, as the search range of the reference image, the reference image reading unit 110 may specify an arbitrary search range, or the user of the moving image coding apparatus 100 may freely specify the search range.

Next, the reference image reading unit 110 stores the reference image read from the external storage device in the internal buffer (step S102). Here, in step S101 and step S102, by storing the image data of the predetermined area of the reference image corresponding to the image to be encoded in the internal buffer, it is not necessary to refer to the external storage device at the time of encoding. Therefore, the delay can be eliminated.

Next, the vector search unit 120 searches the search range of a predetermined area of the reference image read by the reference image read unit 110 in step S102, and calculates a motion vector for each search range (step S103).

Next, the vector search unit 120 calculates an evaluation function for each of the motion vectors calculated for each search range, and compares the evaluation functions (step S104).

Next, the vector search unit 120 selects the motion vector of the best evaluation function as a result of the comparison, and outputs the selected motion vector as the evaluation motion vector (step S105).

Then, the reference image reading unit 110 reads, from the external storage device, a reference image obtained by adding an area having at least twice the length and width of the search range to the search range corresponding to the evaluation motion vector (step S106).

Finally, the reference image reading unit 110 stores the reference image read in step S106 in the internal buffer (step S107).

[Second Embodiment]
FIG. 6 is a block diagram showing a moving picture coding apparatus according to the second embodiment of the present invention.

The moving image coding apparatus 100A according to the second embodiment includes a reference image reading unit 110, a vector searching unit 120, and a vector setting unit 130. That is, the moving picture coding apparatus 100A differs from the moving picture coding apparatus 100 in that the moving picture coding apparatus 100A includes the vector setting unit 130.

The vector setting unit 130 generates a motion vector different from the first to Nth motion vectors generated by the vector search unit 120 as a set motion vector. Here, the method of generating the set motion vector of the vector setting unit 130 may be a simpler method than the method of generating the first to Nth motion vectors by the vector searching unit 120. The vector setting unit 130 generates a set motion vector by searching a wide range of the screen more roughly than the vector searching unit 120, for example, by reducing the size of the image or thinning out the pixels of the image. Further, the vector setting unit 130 may generate a specific motion vector according to the position of the screen as a set motion vector based on the feature amount that is different for each coordinate of the still image obtained by the image analysis. In this case, the vector search unit 120 compares the evaluation function value of the first to Nth motion vectors with the evaluation function value of the set motion vector, and selects one motion vector with the best evaluation function value. The evaluation motion vector is output.

FIG. 7: is a flowchart which shows the flow of operation|movement of 100 A of moving image encoding apparatus which concerns on the 2nd Embodiment of this invention. Hereinafter, with reference to FIG. 7, an operation flow of the moving picture coding apparatus 100A according to the second embodiment of the present invention will be described.

First, the reference image reading unit 110 reads out image data of a predetermined area of the reference image corresponding to the encoding target image from an external storage device that holds a plurality of still images that form a moving image (step S201).

Next, the reference image reading unit 110 stores the reference image read from the external storage device in the internal buffer (step S202).

Next, the vector search unit 120 searches the search range of a predetermined area of the reference image read by the reference image read unit 110 in step S202, and calculates a motion vector for each search range (step S203).

Next, the vector setting unit 130 generates a motion vector different from the motion vector generated by the vector search unit 120 in step S203 as a set motion vector (step S204).

Next, the vector search unit 120 calculates an evaluation function for each of the motion vectors calculated for each search range in step S203 and the set motion vector, and compares the calculated evaluation function (step S205).

Next, the vector search unit 120 selects the motion vector of the best evaluation function as a result of the comparison, and outputs the selected motion vector as the evaluation motion vector (step S206).

Then, the reference image reading unit 110 reads, as a reference image, an area in the search range corresponding to the evaluation motion vector, in which the height and width of the search range in the vector search unit 110 are at least twice as large as the reference image (step S207).

Finally, the reference image reading unit 110 stores the reference image read in step S207 in the internal buffer (step S208).

[Video coding system]
FIG. 8 is a schematic diagram showing the configuration of the moving picture coding system according to the third embodiment of the present invention.

As shown in FIG. 8, the moving image coding system 300 includes a moving image coding device 100 and an external storage device 200.

The external storage device 200 is not particularly limited, but can be configured by, for example, an HDD (Hard Disk Drive) or the like provided inside or outside the moving image encoding device 100. The external storage device 200 may be, for example, a cloud storage existing on the communication network when the moving picture coding device 100 is connected to the communication network such as the Internet.

The operation of the moving picture coding system 300 is the same as that of the moving picture coding apparatus 100, and therefore its explanation is omitted. Further, the moving image coding system 300 may be configured by combining the moving image coding device 100A and the external storage device 200.

[Other Embodiments]
The moving image decoding apparatus 100 (FIG. 1) and the moving image decoding apparatus 100A (FIG. 6) may be realized by hardware or software. Further, the moving picture coding apparatus 100 and the moving picture coding apparatus 100A may be realized by a combination of hardware and software.

FIG. 9 is an example of an information processing device (computer) that configures the moving image coding device 100 (FIG. 1) and the moving image coding device 100A (FIG. 6).

As illustrated in FIG. 9, the information processing device 400 includes a control unit 401, a storage device 402, a ROM (Read Only Memory) 403, a RAM (Random Access Memory) 404, and a communication interface 405.

The control unit 401 can be configured by an arithmetic processing device such as a CPU (Central Processing Unit). The control unit 401 expands a program readable by the control unit 401 stored in the storage device 402 or the ROM 403 into the RAM 404 and executes the program to configure the moving image encoding device 100 and the moving image encoding device 100A. Each part can be realized. Further, the control unit 401 may include an internal buffer that can temporarily store data and the like.

The storage device 402 is a large-capacity storage medium capable of holding various data, and can be realized by a storage medium such as a magneto-optical disk, a HDD (Hard Disc Drive), and an SSD (Solid State Drive). Further, when the information processing device 400 is connected to the communication network via the communication interface 405, the storage device 402 may be a cloud storage existing on the communication network. Further, the storage device 401 may hold a program readable by the control unit 401.

The ROM 403 is a non-volatile storage device that has a smaller capacity than the storage device 401 and can be configured by a flash memory or the like. Further, the ROM 401 may hold a program readable by the control unit 401. The program readable by the control unit 401 may be stored in at least one of the storage device 402 and the ROM 403.

The RAM 404 is a semiconductor memory such as a DRAM (Dynamic Random Access Memory) and an SRAM (Static Random Access Memory), and can be used as an internal buffer for temporarily storing data and the like.

The communication interface 405 is an interface that connects the information processing apparatus 400 and a communication network via a wire or wirelessly.

The whole or part of the exemplary embodiments disclosed above can be described as the following supplementary notes. The following supplementary notes do not limit the present invention.

[Appendix 1]
A reference image reading unit that reads out image data of a predetermined area of a reference image corresponding to an encoding target image from an external storage device that holds a plurality of still images that form a moving image, and stores the image data in an internal buffer.
Using the image data of the predetermined area of the reference image stored in the internal buffer, the first to N-th areas (N is 2 or more) having different ranges with respect to the encoding target area of the encoding target image, respectively. (Integer), a vector search unit that executes a motion search for a search range and generates search results as first to Nth motion vectors, respectively.
The vector searching unit compares the evaluation function values of the first to Nth motion vectors, selects the motion vector with the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image reading unit, from the external storage device, with respect to the search range corresponding to the evaluation motion vector and the search range corresponding to the motion vector on which the vector search unit performs the motion search, the vertical search range. A moving image encoding apparatus which reads out the image data and stores the image data in the internal buffer by using an area obtained by at least doubling the horizontal width and the horizontal width as the predetermined area.

[Appendix 2]
The moving image coding apparatus according to attachment 1, further comprising a vector setting unit that previously generates a set motion vector as one of the first to Nth motion vectors.

[Appendix 3]
The vector setting unit extracts a feature amount for each coordinate of the reference image based on the image data of the predetermined region, and sets the set motion vector according to the feature amount. Video coding device.

[Appendix 4]
From an external storage device that holds a plurality of still images that make up a moving image, read image data in a predetermined area of a reference image corresponding to the image to be encoded, and store it in an internal buffer.
Using the image data of the predetermined area of the reference image stored in the internal buffer, the first to N-th areas (N is 2 or more) having different ranges with respect to the encoding target area of the encoding target image, respectively. (Integer) a motion search is performed for a search range, and search results are generated as first to Nth motion vectors,
Comparing the evaluation function values of the first to Nth motion vector, selecting the motion vector with the best evaluation function value, and output as an evaluation motion vector,
From the external storage device, the search range corresponding to the evaluation motion vector and the search range corresponding to the motion vector on which the vector search unit executes the motion search are at least twice as long and wide as the search range. The moving image encoding method, wherein the image data is read out using the specified region as the predetermined region and stored in the internal buffer.

[Appendix 5]
5. The moving picture coding method according to attachment 4, wherein a set motion vector is generated in advance as one of the first to Nth motion vectors.

[Appendix 6]
6. The moving picture coding method according to attachment 5, wherein a feature amount for each coordinate of the reference image is extracted based on the image data of the predetermined region, and the set motion vector is set according to the feature amount.

[Appendix 7]
Computer,
A reference image reading unit that reads out image data of a predetermined area of the reference image corresponding to the image to be encoded from an external storage device that holds a plurality of still images forming a moving image and stores the image data in an internal buffer;
Using the image data of the predetermined area of the reference image stored in the internal buffer, the first to N-th areas (N is 2 or more) having different ranges with respect to the encoding target area of the encoding target image, respectively. (Integer), a vector search means that executes a motion search for a search range and generates search results as first to Nth motion vectors, respectively.
Means for comparing the evaluation function values of the first to Nth motion vectors, selecting the motion vector with the best evaluation function value, and outputting it as an evaluation motion vector;
From the external storage device, the search range corresponding to the evaluation motion vector and the search range corresponding to the motion vector on which the vector search unit executes the motion search are at least twice as long and wide as the search range. A moving image coding program that causes the specified area to be the predetermined area to read the image data and store the image data in the internal buffer.

[Appendix 8]
8. The moving picture coding program according to appendix 7, further causing the computer to function as a vector setting unit that previously generates a set motion vector as one of the first to Nth motion vectors.

[Appendix 9]
Supplementary Note 8: The computer is caused to further function as a unit that extracts a feature amount for each coordinate of the reference image based on the image data of the predetermined region and sets the set motion vector according to the feature amount. The moving picture coding program according to item 1.

[Appendix 10]
An external storage device that holds a plurality of still images that make up a moving image;
A reference image reading unit that reads out image data of a predetermined area of a reference image corresponding to the encoding target image from the external storage device and stores the image data in an internal buffer;
Using the image data of the predetermined area of the reference image stored in the internal buffer, the first to N-th areas (N is 2 or more) having different ranges with respect to the encoding target area of the encoding target image, respectively. (Integer), a vector search unit that executes a motion search for a search range and generates search results as first to Nth motion vectors, respectively.
The vector searching unit compares the evaluation function values of the first to Nth motion vectors, selects the motion vector with the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image reading unit, from the external storage device, with respect to the search range corresponding to the evaluation motion vector and the search range corresponding to the motion vector on which the vector search unit performs the motion search, the vertical search range. A moving image encoding system in which the image data is read out and stored in the internal buffer with an area obtained by at least doubling the horizontal and horizontal directions as the predetermined area.

[Appendix 11]
The moving image coding system according to attachment 10, further comprising a vector setting unit that previously generates a set motion vector as one of the first to Nth motion vectors.

[Appendix 12]
Item 12. The vector setting unit extracts a feature amount for each coordinate of the reference image based on the image data of the predetermined region, and sets the set motion vector according to the feature amount. Video coding system.

10... Encoding target image 11... Encoding target block 12... Reference image 13... Prediction image 14... Prediction target block 20, 20'... Encoding target image 21... Encoding target block 30, 30'... Reference image 31... Search range 32... Prediction target block 40... Motion vector 50, 60, 70... Reference image 51... Adjacent block 52... .. Search range 53... Prediction target block 54... Search range 55... Additional area 100, 100A... Moving image coding device 110... Reference image reading unit 120... Vector search unit 130・・・ Vector setting unit 200 ・・・ External storage device 300 ・・・ Moving image coding system 400 ・・・ Information processing device 401 ・・・ Control unit 402 ・・・ Storage device 403 ・・・ ROM
404...RAM
405...Communication interface

Claims (8)

A reference image reading unit that reads out image data of a predetermined area of a reference image corresponding to an encoding target image from an external storage device that holds a plurality of still images that form a moving image, and stores the image data in an internal buffer.
Using image data of a predetermined area of the reference image stored in the internal buffer, a vector of an area adjacent to the encoding target area is centered with respect to the encoding target area of the encoding target image. a vector searching unit that the second performs motion search for the search range around zero vector of the first search range and the encoding target area, to produce search results as first and second motion vectors respectively, Equipped with
The vector search unit compares the evaluation function values of the first and second motion vectors, selects the motion vector with the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image read unit corresponds to a previous search range corresponding to the evaluation motion vector previously output by the vector search unit from the external storage device and a motion vector for which the vector search unit next performs a motion search. A moving image coding apparatus, which reads the image data with a region obtained by at least doubling the vertical and horizontal directions of the next search range as the predetermined region and stores the image data in the internal buffer. A vector setting unit that previously generates a set motion vector different from the first and second motion vectors ,
The vector search unit compares the evaluation function values of the first and second motion vectors with the evaluation function value of the set motion vector, selects the motion vector with the best evaluation function value, you output as evaluation motion vector, the moving picture coding apparatus according to claim 1. The reference image reading unit reads image data of a predetermined area of the reference image corresponding to the encoding target image from an external storage device that holds a plurality of still images that form a moving image, and stores the image data in an internal buffer.
The vector search unit uses the image data of the predetermined area of the reference image stored in the internal buffer, with respect to the encoding target area of the encoding target image, of the area adjacent to the encoding target area. A motion search is executed for a first search range centered on a vector and a second search range centered on the zero vector of the encoding target region , and search results are generated as first and second motion vectors, respectively . ,
The vector search unit compares the evaluation function values of the first and second motion vectors, selects the motion vector with the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image read unit corresponds to a previous search range corresponding to the evaluation motion vector previously output by the vector search unit from the external storage device and a motion vector for which the vector search unit next performs a motion search. A moving image encoding method, wherein the image data is read out and stored in the internal buffer with an area obtained by at least doubling the vertical and horizontal directions of the next search area as the predetermined area. A vector setting unit previously generates a set motion vector different from the first and second motion vectors ,
The vector search unit compares the evaluation function values of the first and second motion vectors with the evaluation function value of the set motion vector, selects a motion vector with the best evaluation function value, The video encoding method according to claim 3 , wherein the video is output as an evaluation motion vector . Computer,
A reference image reading unit that reads out image data of a predetermined area of the reference image corresponding to the image to be encoded from an external storage device that holds a plurality of still images forming a moving image and stores the image data in an internal buffer;
Using image data of a predetermined area of the reference image stored in the internal buffer, a vector of an area adjacent to the encoding target area is centered with respect to the encoding target area of the encoding target image. a vector search unit performs the motion search to generate search results as first and second motion vectors respectively, for a second search range centered on the zero vector of the first search range and the encoding target area, Is a moving picture coding program that functions as
The vector search means compares the evaluation function values of the first and second motion vectors, selects the motion vector having the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image reading unit corresponds to a previous search range corresponding to the evaluation motion vector previously output by the vector searching unit from the external storage device, and a motion vector at which the vector searching unit executes a motion search next time. A moving image encoding program for reading the image data with the area obtained by at least doubling the vertical and horizontal directions of the next search area as the predetermined area and storing the image data in the internal buffer. Causing the computer to further function as vector setting means for generating in advance a set motion vector different from the first and second motion vectors ,
The vector searching means compares the evaluation function values of the first and second motion vectors with the evaluation function value of the set motion vector, selects a motion vector having the best evaluation function value, you output as evaluation motion vector, the moving picture coding program according to claim 5. An external storage device that holds a plurality of still images that make up a moving image;
A reference image reading unit that reads out image data of a predetermined area of a reference image corresponding to the encoding target image from the external storage device and stores the image data in an internal buffer;
Using image data of a predetermined area of the reference image stored in the internal buffer, a vector of an area adjacent to the encoding target area is centered with respect to the encoding target area of the encoding target image. a vector searching unit that the second performs motion search for the search range around zero vector of the first search range and the encoding target area, to produce search results as first and second motion vectors respectively, Equipped with
The vector search unit compares the evaluation function values of the first and second motion vectors, selects the motion vector with the best evaluation function value, and outputs it as an evaluation motion vector,
The reference image read unit corresponds to a previous search range corresponding to the evaluation motion vector previously output by the vector search unit from the external storage device and a motion vector for which the vector search unit next performs a motion search. A moving image coding system, wherein the image data is read out and stored in the internal buffer with an area obtained by at least doubling the vertical and horizontal directions of the next search area as the predetermined area. A vector setting unit that previously generates a set motion vector different from the first and second motion vectors ,
The vector search unit compares the evaluation function values of the first and second motion vectors with the evaluation function value of the set motion vector, selects the motion vector with the best evaluation function value, you output as evaluation motion vector, the moving picture coding system according to claim 7.

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