WO2019176361A1

WO2019176361A1 - Video-encoding device and video-encoding method

Info

Publication number: WO2019176361A1
Application number: PCT/JP2019/003643
Authority: WO
Inventors: 宮下　敦; 武居　裕之
Original assignee: 株式会社日立国際電気
Priority date: 2018-03-13
Filing date: 2019-02-01
Publication date: 2019-09-19
Also published as: JP6694905B2; JP2019161424A

Abstract

[Problem] To provide a video-encoding device and a video-encoding method that can improve, even when transfer data is restricted in its amount, image quality of an object intended to be imaged. [Solution] A video-encoding device and a video-encoding method in which divided videos (slices) obtained by dividing a video signal into plural segments are encoded by a plurality of encoding processing units, an aiming data-amount instruction unit 17 detects a region with small changes such as a sky as a strong-compression area, sets an aiming data amount of an encoding processing unit which processes the slices containing many strong-compression areas to a smaller amount by a specified reduction amount compared with a case of equal spacing, and sets an aiming data amount of an encoding processing unit which processes other slices to a larger amount by the reduction amount for enabling generation of larger amount of encoding data, to thereby efficiently allocate the compressed data amount.

Description

Video encoding apparatus and video encoding method

The present invention relates to a video encoding apparatus and a video encoding method that perform compression by division parallel processing, and in particular, a video that can improve the image quality of a target imaging object even if there is a restriction on the amount of data transmission. The present invention relates to an encoding device and a video encoding method.

[Description of Prior Art]
Conventionally, as a compression process used in a video encoding apparatus, there has been a method of controlling the degree of quantization based on distortion when encoded data is decoded. In this method, the amount of data after compression increases or decreases according to the imaging target (picture).
On the other hand, there is also a compression processing method for controlling quantization so that the amount of data after compression is a constant amount. In this method, the image quality after decoding changes depending on the pattern.

In the FPU (Field Pickup Unit) used for relaying marathons, etc., the amount of data that can be transmitted per unit time is limited by the transmission line. ing.

In UHD (Ultra High Definition) represented by 8k video, the number of processing pixels is large, and an image is often divided into a plurality (M) and processed in parallel by M encoding processing units.
For example, the image for one screen is divided into M strip-shaped regions (slices) in the horizontal direction, and parallel processing is performed.

[Example of video division: FIG. 12]
An example of video division will be described with reference to FIG. FIG. 12 is a schematic explanatory diagram illustrating an example of video division, where (a) illustrates an example of a video signal, and (b) illustrates an example of a divided signal.
In the conventional video encoding apparatus, as shown in FIG. 12A, the video signal (SI-VID) for one screen is divided into M strip-shaped videos (slices) as shown in FIG. 12B. Then, each slice is compressed by the corresponding encoding processing unit. Here, an example in which M = 5 is divided into five is shown, and each slice of v_1 to v_5 is encoded by parallel processing.

[Configuration of Conventional Video Encoding Device: FIG. 13]
Next, the configuration of a conventional video encoding device will be described with reference to FIG. FIG. 13 is a schematic configuration diagram of a conventional video encoding device. Here, a configuration in which a video signal is divided into five and parallel processing is performed will be described as an example.
As shown in FIG. 13, the conventional video encoding apparatus includes a video dividing unit 50, an encoding processing unit (1) 51 to an encoding processing unit (5) 55, a data integration unit 56, a target data amount instruction. Part 57.

Each part of the conventional video encoding device will be described.
The video dividing unit 50 divides the input video signal (SI-VID) into a predetermined number (here, 5) slices (v_1, v_2, v_3, v_4, v_5), and each slice corresponds to each. The data is output to the encoding processing units 51 to 55.
The encoding processing unit (1) 51 to the encoding processing unit (5) 55 compress the input slices and output encoded data (CD_1, CD_2, CD_3, CD_4, CD_5), respectively.

The data integration unit 56 receives the encoded data from the encoding processing unit (1) 51 to the encoding processing unit (5) 55, integrates them, and outputs them as compressed data (SCD).
The target data amount instruction unit 57 sets a target data amount for the encoding processing unit (1) 51 to the encoding processing unit (5) 55.

The target data amount is a target value for the encoded data amount generated by each encoding processing unit.
In the FPU, the transmission data amount per unit time is constant (assumed to be D), and the target data amount instruction unit 57 of the conventional video encoding apparatus includes the encoding processing unit (1) 51 to the encoding processing unit (5). The same target data amount is set for 55.
That is, in the conventional video encoding apparatus, when the transmission data amount is D, a target data amount of D / 5 is set in each encoding processing unit.

Then, the encoding processing unit (1) 51 to the encoding processing unit (5) 55 perform the encoding process while adjusting the compression strength so as not to exceed the target data amount (D / 5). .
Specifically, each encoding processor compares the amount of data stored in the buffer memory that stores the encoded data with the target data amount, and adjusts the compression strength (strength). ing.

[Videos of road races, etc.]
By the way, in images such as road races performed outdoors, a pattern including a sky in the background often appears.
The image of the sky is characterized by a long distance and little movement, and because the image is rough and simple with images such as clouds floating somewhere on the blue background or gray clouds spreading all over, Decoding reproduction is possible even with a small amount of compressed data.

On the other hand, in the area below the sky, roadside buildings below the middle distance, as well as short-distance spectators and runners will be imaged, so the moving speed is fast, the pattern is complicated, and the amount of compressed data required is empty. More than that.
As described above, in a video such as a road race, an area where change is small and can be decoded even with a small amount of compressed data, and an area where change is large and a sufficient amount of compressed data is required are mixed.

However, as shown in the lower part of FIG. 13, in the conventional video encoding device, by setting the target data amount equally in all the encoding processing units, the compressed data generated in each encoding processing unit is also equalized. It has become.

That is, when video is divided and encoded, the required amount of compressed data differs depending on the slice, but in the conventional video encoding device, the same target data amount is set in all the encoding processing units, The amount of encoded data is allocated uniformly.
For this reason, the image of the sky part becomes higher definition than necessary, and the image quality cannot be improved in the middle distance or near distance area.

[Camera angle]
Also, in a marathon or the like, the mobile relay camera changes the distance to the runner and the shooting angle (front, diagonal, horizontal) by program development. In addition, the angle of view (the range in which the image is displayed) changes by changing the focal length of the lens.
That is, the size and shape of the empty area change according to the camera angle.

[Related technologies]
Incidentally, as a conventional technique of the video encoding apparatus, there is "Coding apparatus and encoding method" (Patent Document 1) of Japanese Patent Application Laid-Open No. 2016-184912.
In Patent Document 1, in the encoding device, motion data Mv is generated by weighting the detected motion in accordance with the state information of the camera angle and the zoom magnification of the lens, and based on SUM, It is described that data I-CD, data P-CD obtained by P processing, or motion data Mv is selected and output as compressed data.

Japanese Unexamined Patent Publication No. 2016-184912

As described above, in a conventional video encoding apparatus that divides video and performs encoding with a plurality of encoding processing units, there are an area that can be decoded even with a small amount of compressed data, and an area that requires a sufficient amount of compressed data. Even in mixed video, the same target data amount is set for all encoding processing units, so it is possible to improve the image quality by effectively allocating the compressed data amount in a system with limited transmission data amount. There was a problem that it was not possible.

In Patent Document 1, the target data amount of an encoding processing unit that processes a slice including many regions with little change is reduced, and the target data amount of other encoding processing units is increased to obtain more compressed data. There is no mention of improving allocation and image quality.

The present invention has been made in view of the above circumstances, and reduces the target data amount of an encoding processing unit that processes a slice including many regions with little change, and accordingly, the target data amount of another encoding processing unit. To provide a video encoding device and a video encoding method capable of improving the image quality of a target imaging object even when there is a restriction on the amount of transmission data by allocating more compressed data. Objective.

The present invention for solving the problems of the above-described conventional example is a video encoding device provided with a video dividing unit that divides a video signal from a camera into a plurality of slices and corresponding to each slice. A plurality of encoding processing units that perform encoding processing of slices to be output and output compressed data; a data integration unit that outputs compressed data integrated by integrating compressed data output from the plurality of encoding processing units; A target data amount instruction unit that sets a target data amount that is a target amount of generated compressed data for each encoding processing unit, and the encoding processing unit is set by the target data amount instruction unit The compressed data is generated within the range of the target data amount, and the target data amount instruction unit divides the upper limit value of the integrated compressed data amount by the number of slices and stores it as a basic target data amount. Image A small compression area is detected, the ratio of the strong compression area in each slice is calculated, and a specific reduction amount is calculated from the basic target data quantity as the target data quantity of the encoding processing unit corresponding to the slice with a large percentage. As a target data amount for other encoding processing units, the total reduction amount is divided by the number of other encoding processing units and set in addition to the basic target data amount. Yes.

In addition, in the video encoding device, the present invention provides the target data amount instruction unit, when the ratio of the strong compression area in the slice exceeds a preset threshold, If the ratio is equal to or lower than the threshold value, the slice is classified into the second class, and the basic target data is used as the target data amount of the encoding processing unit corresponding to the slice of the first class. A specific reduction amount is set lower than the amount, and as the target data amount of the encoding processing unit corresponding to the second class slice, the total reduction amount is the number of slices classified into the second class. It is characterized by being set in addition to the basic target data amount.

According to the present invention, in the video encoding device, the target data amount instruction unit stores a first reduction amount as a reduction amount and a second reduction amount less than the first reduction amount, and slices If the ratio of the strongly compressed area in is over the first threshold, the slice is classified into the first class, the ratio exceeds the second threshold, and the first threshold If it is less than, classify the slice into the second class, and if the ratio is less than or equal to the second threshold, classify the slice into the third class and As the target data amount of the encoding processing unit corresponding to the slice, the first reduction amount is set lower than the basic target data amount, and as the target data amount of the encoding processing unit corresponding to the second class slice, Set by reducing the second reduction amount from the basic target data amount In addition, as a target data amount of the encoding processing unit corresponding to the slice of the third class, a slice in which the sum of the first reduction amount and the sum of the second reduction amount is classified into the third class It is characterized by being set in addition to the basic target data amount by dividing by the number of.

Further, according to the present invention, in the video encoding device, the target data amount instruction unit calculates a reduction amount of the target data amount of the encoding processing unit corresponding to a slice having a large ratio of the strong compression area based on the ratio. It is characterized by being calculated by a formula.

The present invention is also characterized in that, in the video encoding device, the target data amount instruction section detects a strong compression area based on angle information of a camera angle, tilt, and zoom.

The present invention is also a video encoding method in a video encoding apparatus that divides a video signal from a camera into a plurality of slices and encodes the slices by parallel processing, wherein the target data amount instruction unit is integrated The upper limit value of the compressed data amount divided by the number of slices is stored as a basic target data amount, a strong compression area with a small image change in the video signal is detected, and the ratio of the strong compression area in each slice is determined. Calculate and set a specific reduction amount from the basic target data amount as a target data amount of the encoding processing unit corresponding to a slice with a large ratio, and as a target data amount of another encoding processing unit The total reduction amount is divided by the number of other encoding processing units and added to the basic target data amount.

According to the present invention, a video dividing unit that divides a video signal from a camera into a plurality of slices, and a plurality of codes that are provided corresponding to each slice and that perform compression processing of the corresponding slices and output compressed data Data processing unit, a data integration unit that integrates compressed data output from a plurality of encoding processing units and outputs integrated compressed data, and a target of compressed data generated for each encoding processing unit A target data amount instructing unit for setting a target data amount to be an amount, and the encoding processing unit generates compressed data within the range of the target data amount set from the target data amount instructing unit, and The unit divides the upper limit value of the integrated compressed data amount by the number of slices and stores it as a basic target data amount, detects a strong compression area with a small image change in the video signal, By calculating the ratio of the compression area and setting the target data amount of the encoding processing unit corresponding to the slice with a large ratio by reducing a specific reduction amount from the basic target data amount, As the target data amount, the video encoding device is set in addition to the basic target data amount by dividing the total reduction amount by the number of other encoding processing units, so strong compression that can be sufficiently decoded even with a small amount of code Reduces the amount of compressed data in processing of slices containing many areas, and can increase the amount of compressed data generated in processing of other slices by that amount, even if there is a limit on the amount of transmitted data. There is an effect that the image quality of the region including the object can be improved.

According to the present invention, the target data amount instruction unit classifies the slice into the first class when the ratio of the strongly compressed area in the slice exceeds a preset threshold, and the ratio Is equal to or less than the threshold, the slice is classified into the second class, and the target data amount of the encoding processing unit corresponding to the slice of the first class is a specific reduction from the basic target data amount. A basic target by dividing the total reduction amount by the number of slices classified in the second class as the target data amount of the encoding processing unit corresponding to the second class slices Since the video encoding device is set in addition to the data amount, there is an effect that the image quality of the region including the target imaging object can be improved with a simple process even when the transmission data amount is limited.

Further, according to the present invention, the target data amount instruction unit stores the first reduction amount as the reduction amount and the second reduction amount that is smaller than the first reduction amount, so that the strong compression area in the slice is stored. If the ratio exceeds the first threshold, the slice is classified into the first class, and the ratio exceeds the second threshold and is less than or equal to the first threshold. Classifies the slice into the second class, and classifies the slice into the third class when the ratio is equal to or less than the second threshold, and codes corresponding to the slices of the first class. The target data amount of the encoding processing unit is set by reducing the first reduction amount from the basic target data amount, and the target data amount of the encoding processing unit corresponding to the slice of the second class is determined from the basic target data amount. The second reduction amount is set to be reduced and the third class is set. As the target data amount of the encoding processing unit corresponding to each slice, the sum of the first reduction amount and the sum of the second reduction amount is divided by the number of slices classified into the third class. Since the video encoding device is set in addition to the target data amount, the target data amount to be reduced can be changed step by step according to the ratio of the strong compression area in the slice, and even when the transmission data amount is limited There is an effect that the image quality of the slice including the target imaging target can be improved while appropriately maintaining the image quality of the slice in which the target data amount is reduced.

Further, according to the present invention, the target data amount instruction unit calculates a reduction amount of the target data amount of the encoding processing unit corresponding to a slice having a large ratio of the strong compression area by an arithmetic expression based on the ratio. Since the video encoding apparatus is used, there is an effect that the amount of reduction can be finely controlled instead of a fixed value.

Further, according to the present invention, the target data amount instruction unit is the video encoding device that detects the strong compression area based on the angle information of the camera angle, tilt, and zoom. There is an effect that the area can be calculated.

In addition, according to the present invention, there is provided a video encoding method in a video encoding apparatus that divides a video signal from a camera into a plurality of slices and encodes the slices by parallel processing, wherein the target data amount instruction unit includes: The upper limit value of the integrated compressed data amount is divided by the number of slices and stored as a basic target data amount, and a strong compression area with a small image change in the video signal is detected, and the strong compression area of each slice is detected. The ratio is calculated and the target data amount of the encoding processing unit corresponding to the slice having a large ratio is set by reducing the specific reduction amount from the basic target data amount, and the target data of the other encoding processing unit Since the video encoding method is set in addition to the basic target data amount by dividing the total reduction amount by the number of other encoding processing units, sufficient decoding is possible even with a small code amount. The amount of compressed data in the processing of slices that contain many strong compression areas can be reduced, and the amount of compressed data generated in processing of other slices can be increased accordingly, even if the amount of transmitted data is limited. There is an effect that the image quality of the region including the imaging target to be improved can be improved.

It is a schematic block diagram of a video encoding apparatus according to an embodiment of the present invention. 3 is a configuration block diagram of an encoding processing unit 11. FIG. It is explanatory drawing which shows the example of the target data amount setting in this encoding apparatus. It is explanatory drawing which shows the relationship (1) of angle information and a strong compression area. It is explanatory drawing which shows the relationship (2) of angle information and a strong compression area. It is explanatory drawing which shows the relationship (3) of angle information and a strong compression area. It is explanatory drawing which shows the relationship (4) of angle information and a strong compression area. 5 is a flowchart showing processing in a target data amount instruction unit 17. It is a schematic explanatory drawing which shows the example of a video signal. It is explanatory drawing which shows the example of calculation of the empty area in a basic state. It is explanatory drawing which shows the example of calculation of the empty area using the angle information of a camera. It is a schematic explanatory drawing which shows the example of a video division | segmentation, (a) shows the example of a video signal, (b) shows the example of the divided | segmented signal. It is a schematic block diagram of the conventional video coding apparatus.

Embodiments of the present invention will be described with reference to the drawings.
[Outline of the embodiment]
A video encoding device (main encoding device) and a video encoding method (main encoding method) according to an embodiment of the present invention include a plurality of encoding processing units for dividing a divided video (slice) into a plurality of video signals. The target data amount instruction unit detects an area with a small change such as the sky as a strong compression area based on angle information such as the tilt, angle, and zoom of the camera, and detects the strong compression area. Set the target data amount of the encoding processing unit that processes many slices to a smaller value than the case of equal allocation, and increase the target data amount of the encoding processing unit that processes other slices accordingly By generating data, even if there is a restriction on the amount of transmitted data, it is possible to effectively allocate the compressed data amount and improve the image quality of the area including the target imaging object. A.

[Configuration of Video Encoding Device According to Embodiment: FIG. 1]
FIG. 1 is a schematic block diagram of a video encoding apparatus according to an embodiment of the present invention.
This encoding apparatus is configured as a part of an FPU that encodes and transmits video from a camera mounted on a relay vehicle, for example.
As shown in FIG. 1, the present encoding apparatus includes an encoding unit 1, and the encoding unit 1 is connected to a camera 20 and an angle detection unit 21.

For example, the camera 20 is mounted on a mobile relay vehicle or the like, captures a video such as a road race, and outputs it as a video signal (SI-VID).
The angle detection unit 21 acquires information related to the angle of the camera 1 and outputs it as angle information. The angle information includes an angle (An), a tilt (Ti), and a camera field angle (Zm; zoom).
Here, the angle indicates a horizontal angle, the tilt indicates a vertical angle, and the camera field angle indicates a zoom range.

The encoding unit 1 divides the video signal into a plurality of slices, encodes each slice in parallel with different encoding processing units, integrates the plurality of encoded data, and outputs compressed data.
In particular, in the present encoding device, a strongly compressible area (strong compression area) is calculated based on the angle information from the angle detection unit 21, and each encoding process is performed according to the ratio of the strong compression area in each slice. The image quality of the area including the target imaging object is improved by increasing / decreasing the target data amount of the part.

Here, the case where the strong compression area is an empty image will be described as an example. However, if the area is a simple pattern with little change, such as a distant road, sea, or forest, it is strong regardless of the type of subject. It can be a compression area.

Each unit of the encoding unit 1 will be described. Here, a configuration in which a video signal is divided into five slices and parallel processing is performed will be described as an example, but the present invention is not limited to this.
The basic configuration of the encoding unit 1 is the same as that of the conventional encoding unit shown in FIG. 13, and includes a video dividing unit 10, an encoding processing unit (1) 11 to an encoding processing unit (5) 15, A data integration unit 16 and a target data amount instruction unit 17 are provided.
Among these components, the target data amount instruction unit 17 is a characteristic part of the present encoding device.

The video dividing unit 10 divides the video signal (SI-VID) input from the camera into five slices (V_1, V_2, V_3, V_4, V-5).
The encoding processing unit (1) 11 (hereinafter referred to as the encoding processing unit 11) encodes the slice V_1 and outputs encoded data CD_1.
The encoding processing unit (2) 12 (hereinafter referred to as the encoding processing unit 12) encodes the slice V_2 and outputs encoded data CD_2.
The encoding processor (3) 13 (hereinafter referred to as the encoding processor 13) encodes the slice V_3 and outputs encoded data CD_3.
The encoding processing unit (4) 14 (hereinafter referred to as the encoding processing unit 14) encodes the slice V_4 and outputs encoded data CD_4.
The encoding processing unit (5) 15 (hereinafter referred to as the encoding processing unit 15) encodes the slice V_5 and outputs encoded data CD_5.

The data integration unit 16 integrates the encoded data CD_1, CD_2, CD_3, CD_4, CD_5, and outputs compressed data (SCD).
The target data amount instruction unit 17 is a characteristic part of the present encoding device, and includes a strong compression area calculation unit 18 and a target data calculation unit 17, and each of the encoding processing unit 11 to the encoding processing unit 15 has a target data amount. Set the amount of data.

The strong compression area calculation unit 18 calculates an area (strong compression area) that can be strongly compressed in the video signal (SI-VID) for one screen based on the angle information from the angle detection unit 21.
The calculation of the strong compression area will be described later.

Further, the strong compression area calculation unit 18 calculates the ratio (r) of the strong compression area in each divided video signal (slice), and classifies the slices into a plurality of classes based on the ratio.
Specifically, the strong compression area calculation unit 18 stores a threshold value for classifying slices into a plurality of classes in advance, and compares the threshold value with the ratio of the strong compression area of each slice. Classify slices into classes.

For example, the strong compression area calculation unit 18 classifies the class as a class 1 if the ratio (r) of the strong compression area in the slice is r> 80%, and class 2 if r ≦ 80%.
Here, slices classified as class 1 have a high ratio of strong compression areas, and even if they are strongly compressed, the image quality degradation is small, so that the target data amount can be set small.
The slice classification will be described later.

The target data amount calculation unit 19 calculates a target data amount corresponding to the classified class according to the number of slices classified into each class, and sends the target data amount to the encoding processing unit 11 to the encoding processing unit 15, respectively. Target data amounts TD1 to TD5 are set.

The target data amount calculation unit 19 stores a reduction data amount corresponding to the class in advance. Here, it is assumed that the reduced data amount α is stored corresponding to the class 1.
The reduced data amount is a data amount that is reduced from the target data amount (reference target data amount) when the target data amount is uniformly allocated to all the encoding processing units.

In the lower part of FIG. 1, an image of the integrated compressed data is shown.
FIG. 1 shows a case where slice V_1 is classified into class 1, and slice V_2 to slice V_5 are classified into class 2.
In this case, the target data calculation unit 19 reduces the target data amount TD1 of the encoding processing unit 11 corresponding to the slice V_1 by α as compared with the data amount of even allocation. As a result, as shown in FIG. 1, the data amount of the compressed data CD_1 generated in the encoding processing unit 11 is also reduced by α as compared with the data amount of even allocation.
Since the slice V_1 includes many empty portions, it can be sufficiently decoded even with a small amount of compressed data.

Then, the target data calculation unit 19 distributes the compressed data amount α reduced by the encoding processing unit 11 to the TD encoding processing unit 12 to the encoding processing unit 15, and these encoding processing units 12 to 15 The generated compressed data CD_2 to CD_5 is increased by α / 4 as compared with the reference data amount of uniform allocation.
By performing such processing, it is possible to improve the image quality by allocating a larger amount of encoded data to a region including the target imaging object without increasing the overall data amount.
The processing in the target data amount instruction unit 17 will be described later.

[Configuration of Encoding Processing Unit: FIG. 2]
Next, the configuration of each encoding processing unit in the video encoding apparatus will be described with reference to FIG. FIG. 2 is a block diagram illustrating the configuration of the encoding processing unit 11. Here, the encoding processing unit 1 will be described as an example, but the encoding processing unit 12 to the encoding processing unit 15 have the same configuration.
As illustrated in FIG. 2, the encoding processing unit 11 of the present encoding device includes a control unit 31 and I (Intra-co
It includes a ded picture (Processing unit) 32, a P (Predictive-coded Picture) processing unit 33, a selection unit 34, a buffer memory 35, and a decoding unit 36.

Each unit of the encoding processing unit 11 will be described.
The control unit 31 outputs a control signal to each unit, adjusts the strength of compression, and controls the data amount of the compressed data (S-CD).
The processing of the control unit 31 will be described later.

The I processing unit 32 performs processing for generating compressed data (I-CD) as an I frame from the input slice V_1. The I frame is a frame that is encoded without using prediction (interframe prediction) from the preceding and succeeding frames.

The P processing unit 33 performs processing for generating compressed data (P-CD) as a P frame from the video signal (SI-VID) and decoded data (V-DEM) described later. The P frame is a frame composed of difference data between the current video frame and the previous video frame.

The selection unit 34 selects either compressed data (I-CD) from the I processing unit 32 or compressed data (P-CD) from the P processing unit 33 in accordance with the I / P control signal from the control unit 31. To output the selected compressed data (S-CD).

The buffer memory 35 stores the compressed data (S-CD) output from the selection unit 34 and outputs the compressed data (CD_1). In addition, the buffer memory 35 outputs information (SUM: compressed data amount information) related to the amount of accumulated compressed data to the control unit 31.
The decoding unit 36 decodes the selected compressed data (S-CD) and outputs decoded data (V-DEM).

The control unit 31 outputs to the selection unit 34 an I / P control signal that instructs whether to select an I-CD or a P-CD. The I / P control signal is a control signal instructing to select an I-CD at a specific timing and to select a P-CD otherwise.
The output interval of I frames (for example, once every 2 seconds) is set so that the amount of compressed data and the image quality after decoding are appropriate.

Further, the control unit 31 outputs a compression (comp) control signal for increasing or decreasing the amount of compressed data to be generated to the I processing unit 32 and the P processing unit 33 based on the SUM value from the buffer memory 35.
The I processing unit 32 and the P processing unit 33 increase or decrease the amount of generated code by changing the roughness of quantization based on the comp control signal.

Specifically, the target data amount TD1 is set in the control unit 31 from the target data amount instruction unit 17 shown in FIG. 1, and the SUM value is compared with the target data amount TD1, Control the threshold.
For example, when SUM> target data amount TD1 (when the memory capacity of the buffer memory 35 is not sufficient), the control unit 31 increases the quantization threshold value with the comp control signal to 0 (zero). The frequency of the truncated coefficient is increased, the high frequency component is reduced, and the amount of compressed data S-CD input to the buffer memory 35 is suppressed.

When SUM≈target data amount TD1, the comp control signal is maintained, the threshold value is maintained, and the code generation pace is maintained.
Furthermore, when SUM <target data amount TD1 (when the capacity of the buffer memory 35 has a margin), the quantization threshold values in the I processing unit 32 and the P processing unit 33 are set low, and many codes are set. Keep the data.
By setting the quantization threshold low, the high frequency component of the DCT coefficient tends to remain.

In this way, the control unit 31 adjusts the roughness of quantization by the comp control signal based on the magnitude of the data amount (SUM value) accumulated in the buffer memory 35 and the target data amount, and creates a new It controls the amount of generated data.

[Operation of this encoding apparatus: FIGS. 1 and 2]
The operation of this encoding apparatus will be described with reference to FIGS.
First, as shown in FIG. 1, the video signal (SI-VID) input from the camera is input to the encoding unit of the video encoding device, and a predetermined number (here, 5) is input by the video dividing unit 10. Divided into slices. Each slice is input to the corresponding encoding processing unit 11-15.

On the other hand, angle information from the angle detection unit 21 is input to the target data amount instruction unit 17, and the strong compression area calculation unit 18 calculates a strong compression area based on the angle information, and further, a strong compression area in each slice. The ratio (r) is calculated, slices are classified based on the ratio, and the number of slices for each class is obtained.
Then, the target data calculation unit 19 calculates target data amounts TD1 to TD5 corresponding to the classes according to the number of slices for each class, and sets them in the encoding processing units 11 to 15.

Next, the operation of the encoding processing units 11 to 15 will be described using the encoding processing unit 11 as an example.
As shown in FIG. 2, the slice V_1 input to the encoding processing unit 11 is input to the I processing unit 32 and the P processing unit 33, and the I processing unit 32 outputs compressed data I-CD as an I frame. Then, the compressed data P-CD as a P frame is output from the P processing unit 33.
At that time, the I processing unit 32 and the P processing unit 33 perform quantization according to the comp control signal from the control unit 31 so that the compressed data amount does not exceed the set target data amount TD1.

Then, the selection unit 34 selects the compressed data (I-CD) from the I processing unit 32 or the compressed data (P-CD) from the P processing unit 32 based on the I / P control signal from the control unit 31. The selected compressed data (S-CD) is stored in the buffer memory 35 and output as compressed data. Based on the I / P control signal, the selection unit 34 selects an I-CD at a predetermined timing set in advance.

The buffer memory 35 outputs information (SUM) indicating the accumulated amount of data to the control unit 31, and the control unit 31 compares the SUM value with the target data amount TD1 to adjust the comp control signal.
In this way, the operation of the present encoding device is performed.

[Target data amount setting: Fig. 3]
Next, setting of the target data amount in the present encoding device will be described with reference to FIG. FIG. 3 is an explanatory diagram illustrating an example of target data amount setting in the present encoding device.
In FIG. 3, an empty area is determined as a strong compression area, the target data amount of the encoding processing unit corresponding to a slice (strong compression slice) with a high ratio of the strong compression area is reduced, and the other amount is encoded. An example is shown in which the target data amount of the processing unit is added and set.
Assuming that the data transmission amount per unit time is D and the number of slices to be processed in parallel is M, the target data amount (reference target data amount) of each encoding processing unit is D / M when allocated equally.

[First method]
In the first method, slices are classified into two classes using one threshold value, and a certain amount of data is reduced from the target data amount for processing of slices with a high proportion of strongly compressed areas. Allocate minutes for processing of other slices.
For example, assuming that the threshold is 80%, slices in which the ratio (r) of the strongly compressed area exceeds 80% are classified into class 1, and slices having 80% or less are classified into class 2. Further, the reduction data amount (reduction amount) of class 1 is set to α.
In the first method, slices classified as class 1 correspond to strongly compressed slices.

FIG. 3A shows a state in which the top slice includes many strong compression areas (for example, empty images). The top slice is class 1 and the other slices are class 2. are categorized.
In this case, in this encoding apparatus, the target data amount corresponding to the slice of class 1 is reduced by α, and the target data amount of the encoding processing unit 11 (described as processing 1) is set to D / M−α.

Then, the reduced data amount (α) is allocated to the processing of the class 2 slice in which the ratio of the strong compression area is 80% or less. That is, the target data amount of the encoding processing unit 12 to the encoding processing unit 15 (processing 2 to processing 5) is set to D / M + α / 4.

FIG. 3B shows a case where the ratio of the strong compression areas of the first and second slices from the top exceeds 80%. That is, slices V_1 and V_2 are classified as class 1, and other slices are classified as class 2.
In this case, the target data amounts of the encoding processing unit 11 and the encoding processing unit 12 are respectively reduced by α to be D / M−α.
Then, the reduced 2α data amount is allocated to the other encoding processing units 13 to 15 (processing 3 to processing 5), and the target data amount of these encoding processing units is set to D / M + 2α / 3. And

That is, if the amount of data to be reduced in the processing of the slices classified into class 1 classified as class 1 is α, the target data amount in the processing of class 1 is fixed at D / M−α, but class 2 The target data amount varies depending on the number m of slices classified into class 1.
Specifically, the allocation data amount of each class is calculated as follows.
Class 1: TD_c1 = D / M-α (Formula 1)
Class 2: TD_c2 = D / M + (m · α) / M−m (Formula 2)

[Second method]
In the second method, the threshold is set in two stages (for example, 80% and 40%), and slices are classified into three classes (class 1, class 2, class 3) according to the ratio of the strong compression area. Set the target data volume. In the second method, slices classified into class 1 and class 2 correspond to strong compression slices.
It is assumed that the target data amount calculation unit 19 stores a data reduction amount α corresponding to class 1 and a data reduction amount β corresponding to class 2. Here, α> β, α corresponds to the first reduction amount described in the claims, and β corresponds to the second reduction amount.

FIG. 3C shows a state where the ratio of the strong compression area of the second slice is smaller than that of the first slice.
In this case, the first slice in which the proportion of the strong compression area exceeds 80% is classified as class 1, and the second slice in which the proportion of the strong compression area is 40% to 80% (40 <r ≦ 80) is class 2. are categorized.
Thus, the target data amount calculation unit 19 sets the target data amount of the encoding processing unit 11 (processing 1) to D / M-α, and sets the target data amount of the encoding processing unit 12 (processing 2) to D / M−. Set as β.

Then, the reduced (α + β) data amount is distributed to the encoding processing unit 13 to the encoding processing unit 15 that process the slice of class 3, and the target data amount of these encoding processing units is set to D / M + ( α + β) / 3.

That is, assuming that the number of slices classified into class 1 is ma and the number of slices classified into class 2 is mb, the allocation data amount of each class is calculated as follows. The target data amount in the processing of class 3 slices depends on the number of slices classified into class 1 and class 2.
Class 1 target data volume: TD_c1 = D / M-α (Formula 1)
Class 2 target data amount: TD_c2 = D / M-β (Formula 3)
Class 3 target data amount: TD_c3 = D / M + (ma · α + mb · β) / (M−ma−mb) (Formula 4)

In this way, while reducing the target data amount of the encoding processing unit that processes a slice containing a large amount of the strong compression area, a large amount of code or data is used for processing a slice with a small proportion of the strong compression area (complex pattern). The amount is assigned to improve the image quality of the region including the target imaging object.

[Relationship between angle information and strong compression area: Fig. 4 to Fig. 7]
Next, the relationship between the angle information and the strong compression area will be described with reference to FIGS.
Here, a case will be described as an example where the above-described second method is adopted, slices are classified into three stages using two types of threshold values, and a target data amount is assigned.
[Relationship between angle information and strong compression area (1): FIG. 4]
FIG. 4 is an explanatory diagram showing the relationship (1) between the angle information and the strong compression area.
As shown in FIG. 4A, FIGS. 4D and 4E show the state of the camera when shooting an image taken from the front of the runner. (D) is explanatory drawing seen from the top (top view), (e) is explanatory drawing seen from the side (side view).

As shown in FIG. 4D, the camera angle (horizontal angle) is 0 (zero) °, and the front is photographed. Further, as shown in FIG. 4E, the tilt (vertical angle) of the camera is also 0 °, and the imaging surface is vertical.
That is, FIGS. 2A and 2B show an image and an empty area in the reference state (angle = 0 °, tilt = 0 °).

Then, the strong compression area calculation unit 18 of the target data amount instruction unit 17 calculates an empty area (strong compression area) on the screen based on the video signal (a) based on the angle information from the angle detection unit 21. The strong compression area is calculated as shown in (b), for example.
Further, the strong compression area calculation unit 18 calculates the ratio (r) of the strong compression area in each slice based on the information of the strong compression area of (b), and compares the slice with the threshold value in three stages. Class.

Here, in the second method described above, slices with r> 80% are classified into class 1, slices with 40% <r ≦ 80% are classified into class 2, and slices with r ≦ 40% are classified into class 3. To do. Further, the data reduction amount of class 1 is α, and the data reduction amount of class 2 is β.

FIG. 4C shows the number of slices classified into each class.
That is, when the strong compression area is calculated as shown in (b), the class 1 slice number ma = 1, the class 2 slice number mb = 1, and the class 3 slice number mc = 3.
Assuming that the target data amount D / M = TD (basic target data amount) when the target data amount is evenly divided by the five encoding processing units, (Equation 1), (Equation 3), (Equation 4) described above. Based on the above, the target data amount of classes 1 to 3 is calculated as follows.
Class 1: TD_c1 = TD-α
Class 2: TD_c2 = TD-β
Class 3: TD_c3 = TD + (α + β) / 3

Then, the target data amount instruction unit 17 sets TD1 = TD−α, TD2 = TD−β, and TD3 = TD4 = TD5 = TD + (α + β) as the target data amounts (TD1 to TD5) of the encoding processing units 11 to 15. / 3 is set.

[Relationship between angle information and strong compression area (2): FIG. 5]
FIG. 5 is an explanatory diagram showing the relationship (2) between the angle information and the strong compression area.
In FIGS. 5A and 5B, as shown in FIGS. 5D and 5E, the camera orientation is in a state where the angle = 0 ° and the tilt = −10 °. In other words, the camera is facing 10 ° downward from the horizontal direction.
In this state, an image as shown in (a) is taken, and as shown in (b), the empty area is narrower than that in FIG.

In the state of FIG. 5 (b), the top slice (slice V_1) is classified as class 1 and the others are classified as class 3, so that ma = 1, mb = 0, mc = 4.
Class 3 target data volume is
TD_c3 = TD + α / 4 is calculated.
Therefore, the target data amount instruction unit 17 sets TD1 = TD−α and TD2 = TD3 = TD4 = TD5 = TD + α / 4 in the encoding processing units 11 to 15.

[Relationship between angle information and strong compression area (3): FIG. 6]
FIG. 6 is an explanatory diagram showing the relationship (3) between the angle information and the strong compression area.
In FIGS. 6A and 6B, as shown in FIGS. 6D and 6E, the camera orientation is such that the angle = 0 ° and the tilt = + 10 °, and the camera is 10 ° upward from the horizontal direction.
In this state, as shown in (a), a video with an increased sky area is taken. The strong compression area is calculated as shown in (b).

Based on this, when the slices are classified, slice V_1 and slice V_2 are classified as class 1, slice V_3 is classified as class 2, slice V_4 and slice V_5 are classified as class 3.
That is, as shown in (c), ma = 2, mb = 1, and mc = 2.
In this case, the target data amount of class 3 is
TD_c3 = TD + (2α + β) / 2 is calculated.
Therefore, the target data amount instruction unit 17 sets TD1 = TD2 = TD−α, TD3 = TD−β, TD4 = TD5 = TD + (2α + β) / 2 in the encoding processing units 11 to 15.

[Relationship between angle information and strong compression area (4): FIG. 7]
FIG. 7 is an explanatory diagram showing the relationship (4) between the angle information and the strong compression area.
In FIG. 7, as shown in (d) and (e), the camera orientation is in a state where the angle = 10 ° and the tilt = 0. That is, the camera is facing 10 ° leftward from the front.
In this state, an image in which the runner approaches the right side of the screen as shown in (a) is taken, and as shown in (b), the sky area has an asymmetric shape.

In this case, the slice V_1 is classified as class 1, the slice V_2 is classified as class 2, and the slices V_3 to V_5 are classified as class 3.
That is, as shown in (c), ma = 1, mb = 1, and mc = 3, and the same target data amount as in the example shown in FIG. 4 is set.
Therefore, the target data amount instruction unit 17 sets TD1 = TD−α, TD2 = TD−β, TD3 = TD4 = TD5 = TD + (α + β) / 3 in the encoding processing units 11 to 15.

Although illustration is omitted, by adjusting the zoom of the camera lens, the angle of view of the camera changes, and the sky region changes accordingly.
In FIGS. 4 to 7, the zoom is constant.

That is, as shown in FIGS. 4 to 7, the shape of the empty area on the screen changes with changes in the camera angle such as angle, tilt, and zoom.
In this encoding apparatus, using this fact, an empty area with small motion is determined as a strong compression area, and the target data amount of a slice having a high ratio of the strong compression area is reduced, and the target data of another slice is also determined. The amount is increased to improve the image quality of the target imaging object.

[Processing in Target Data Amount Instructing Unit: FIG. 8]
Next, the process in the target data amount instruction | indication part 17 is demonstrated using FIG. FIG. 8 is a flowchart showing processing in the target data amount instruction unit 17. FIG. 8 shows processing for a video signal for one screen.
As shown in FIG. 8, when the angle information (An, Ti, Zm) is input from the angle detection unit 21 (100), the target data amount instruction unit 17 calculates a strong compression area based on them (102). ). A method for calculating the strong compression area will be described later.
The target data amount instruction unit 17 sets the class 1 slice number ma = 0 and the class 2 slice number mb = 0 as initial values (104).

The target data amount instruction unit 17 first calculates the ratio (r) of the strongly compressed area in the first slice with the slice number n = 1 (106), compares r with a threshold value, and compares the slice with the slice number n = 1. Are classified into one of

classes

1, 2 and 3 (108). When returning from processing 140 described later, 1 is added to the slice number (n = n + 1), and processing is performed for the nth slice.

When r> 80%, the target data amount instruction unit 17 classifies the slice into class 1 (110) and sets ma = ma + 1 (112).
If 40% <r ≦ 80%, the target data amount instruction unit 17 classifies the slice into class 2 (120) and sets mb = mb + 1 (122).
If r ≦ 40%, the target data amount instruction unit 17 classifies the slice into class 3 (130).

Then, the target data amount instructing unit 17 compares the slice number (n) with the total number of slices (M), and determines whether all slices have been classified (n ≧ M) (140). If it has not ended (in the case of No), the processing returns to the processing 106 and the next slice is classified.

In the process 140, when the classification is completed for all slices (in the case of Yes), the target data amount instruction unit 17 sets the target data amount of the encoding processing unit that performs the processing of the slices classified into the class 1 as TD. Set to -α (142).
Here, TD is a value obtained by dividing the upper limit (the amount of data that can be transmitted) of the compressed data amount output from the present encoding device by the total number of slices to be processed in parallel, and is equal to all the encoding processing units. This is the target data amount (basic target data amount) when the target data amount is assigned to.
Further, the target data amount setting instructing unit 17 sets the target data amount of the encoding processing unit that performs processing of slices classified into class 2 to TD-β (144).

Then, the target data amount instructing unit 17 sets the target data amount (TD_c3) in the encoding processing unit that performs class 3 slice processing based on the number of slices classified into class 1 and class 2 (ma, mb). Is calculated as TD_3 = TD + (ma · α + mb · β) / (M− (ma + mb)) (146). Here, M is the total number of slices, the denominator corresponds to the number of slices classified into class 3, and the numerator corresponds to the target data amount reduced by the processing of slices classified into class 1 and class 2.
Then, the target data amount of the encoding processing unit that performs class 3 slice processing is set to TD_3 (148), and the processing ends.

In the processing shown in FIG. 8, processing 100 to processing 140 are performed by the strong compression area calculation unit 18, and processing 142 to processing 148 are performed by the target data amount calculation unit 19.
In this way, processing in the target eye data amount instruction unit 17 is performed.

[Example of video signal: FIG. 9]
Next, an example of a video signal will be described with reference to FIG. FIG. 9 is a schematic explanatory diagram illustrating an example of a video signal. Here, the signal structure of the high vision is shown.
As shown in FIG. 9, in the two-dimensional image, the horizontal direction indicates the video period (horizontal), and the vertical direction indicates the video period (vertical). The information in the thick frame is video information displayed on one screen. In high vision, the number of effective scanning lines in the video display period (vertical) is 1080 and the number of effective pixels included in one scanning line is 1920 pixels.

As a two-dimensional image, a horizontal blanking period is provided on the left side of video information for one screen, and a vertical blanking period is provided on the lower side. The blanking period is an invalid period, and a line number (scanning line number) is inserted in the horizontal blanking period.
The control unit can recognize the video display start timing by searching for the line No = 1 in the horizontal blanking period generated following the last scanning line 1125 from the input video signal.

In the time axis signal image, video signals are output in order from line No = 1 in units of scanning lines. A horizontal blanking period is provided before the video signal of each scanning line, and a portion corresponding to the 1081st to 1125th scanning lines is a vertical blanking period.

[Calculation of strong compression area: FIGS. 10 and 11]
Next, a calculation example of the strong compression area (empty area, empty area) in the present encoding device will be described with reference to FIGS. FIG. 10 is an explanatory diagram illustrating an example of calculating an empty area in the basic state, and FIG. 11 is an explanatory diagram illustrating an example of calculating an empty area using angle information of the camera.
In this encoding apparatus, an empty area is approximated by a triangle and calculated.

[Example of calculation in basic state: FIG. 10]
First, an example of calculating an empty area when the camera is in the basic state will be described with reference to FIG.
FIG. 10A shows an example of an image when tilt = 0 ° and angle = 0 °, and this state is a basic state. In the basic state, it is assumed that there is a vanishing point of the empty area in the center of the screen, and this point is set as the vertex of the empty area (empty area vertex) approximated by a triangle.

As shown in FIG. 10B, the empty area vertex in the basic state is set as a point P0.
In the high-definition video, the number of pixels in the horizontal direction is 1920 pixels, and the number of lines in the vertical direction is 1080. Therefore, the coordinates (pixel number, line number) of the empty area vertex P0 in the basic state are (960, 540).
Then, a triangular area having apexes at the point P0, the upper left corner (0, 0), and the upper right corner (0, 1920) is defined as an empty area in the basic state.

[Example of calculation using angle information: FIG. 11]
Next, a case where an empty area is calculated using angle information will be described with reference to FIG.
FIG. 11A shows an example of an image when the tilt and angle are not 0 °, and the vanishing point (empty area vertex) P1 moves in the upper right direction of the screen compared to the basic state. The zoom amount in FIG. 11 is the same as that in FIG.
If the horizontal displacement from the point P0 is Hof and the vertical displacement is Vof, the coordinates of the point P1 are (960 + Hof, 540 + Vof).

Horizontal displacement Hof is
Hof = Kh / 2 × tan (angle angle) / tan (horizontal angle of view / 2) Calculated as equation (5).
Here, Kh is the number of pixels in the horizontal direction (1920), and the sign of the angle angle is negative on the left and positive on the right with respect to the center. The horizontal angle of view is determined by the zoom value, and is large when the angle is wide and small when the distance is telephoto.

The vertical deviation Vof is
Vof = Kv / 2 × tan (tilt angle) / tan (vertical angle of view / 2) Calculated as equation (6).
Here, Kv is the number of lines in the vertical direction (1080), and the sign of the tilt angle is minus on the top and plus on the bottom. The vertical angle of view is determined by the zoom value, and is large for wide angles and small for telephoto.
FIG. 10B shows a case where the sign of the angle angle is plus and the sign of the tilt angle is minus.

Thus, based on the camera angle information, Hof and Vof are calculated by equations (5) and (6) to determine the coordinates of the empty area vertex P1, the empty area vertex P1, the upper left corner of the screen, and the upper right corner of the screen. A triangular area having apexes at the three corners is defined as an empty area on the screen.
In the present encoding apparatus, an empty area can be calculated by a simple calculation by approximating with a triangle.

Here, the case where the empty area is approximated by a triangle has been described, but when the zoom amount becomes large, it may be approximated as a trapezoid instead of a triangle.
For example, a point (referred to as point Q and point R) that is moved by a certain length (number of pixels) to the left and right according to the zoom amount with the empty area vertex P obtained by the above-described method as the center is defined as the lower bottom vertex. To do. Then, a trapezoidal region having apexes at the upper left corner, point Q, point R, and upper right corner of the screen is determined as an empty area.
In this way, an empty area can be accurately obtained even when the zoom amount increases.

Then, the target data amount instruction unit 17 of the present encoding apparatus detects the video start timing (line = 1) from the video signal (SI-VID) and inputs angle information, as shown in FIG. An empty area in the video signal for one screen is calculated and the information is retained.

Further, the target data amount instruction unit 17 holds a line number that is an image area of a slice divided by the video dividing unit 10.
Then, the target data amount instruction unit 17 compares the calculated empty area with the area of each slice according to the processing shown in FIG. 8, calculates the ratio (r) of the empty area in the slice, and The target data amount of a slice having a high area ratio is reduced, and the target data amount of a normal slice having a low empty area ratio is increased and set.

In this way, in the present encoding device, even if there is a restriction on the amount of transmission data, the compressed data is set by setting the target data amount low in processing of a slice (strong compression slice) that includes a large area such as a background with little change. In addition to reducing the amount, the target data amount for other slice processing is set higher and more compressed data is allocated to efficiently distribute the compressed data amount and improve the image quality of the target object It can be made to.

[Application to motion vectors]
Since the strong compression area calculated by the present encoding device is an area with small motion, the motion vector is small.
Therefore, the motion vector header can be omitted for the strong compression area, and the data amount can be further reduced.

[Effect of the embodiment]
According to the present encoding device and the present encoding method, a divided video (slice) obtained by dividing a video signal into a plurality of parts is encoded by a plurality of encoding processing units, and the target data amount indicating unit 17 Based on the camera angle information input from the detection unit 21, a region with a small change such as the sky is detected as a strong compression area, and the target data amount of the encoding processing unit that processes slices including many strong compression areas is equalized. Since it is set to be smaller than the case of allocation and a large amount of encoded data is generated by setting the target data amount of the encoding processing unit that processes other slices accordingly, there is a restriction on the amount of transmission data. Even if it exists, there exists an effect which can improve the image quality of the area | region containing the target imaging target object by allocating the amount of compression data effectively.

Further, according to the present encoding device and the present encoding method, the target data amount instruction unit 17 stores a threshold value for classifying slices, and the ratio of the strong compression area in the slice indicates the threshold value. If the target data is evenly allocated to all the encoding processing units to the encoding processing unit corresponding to the strong compression slice, the certain amount is reduced from the reference target data amount The target data amount is set as the target data amount, and the data amount reduced by the strong compression slice is distributed to the encoding processing units corresponding to the other slices and added to the reference target data amount. Therefore, the target data amount of each encoding processing unit can be calculated and set with a simple process, and even if there is a restriction on the transmission data amount, the compressed data amount can be effectively allocated to the target. There is an effect that it is possible to improve the image quality of a region including the imaging object.

In the example described above, the slices are classified into a plurality of classes using the ratio (r) of the strong compression area in the slice and the threshold value, and the target data amount in the encoding processing unit corresponding to the strong compression slice is set to a certain amount ( (Fixed value) is reduced, but an arithmetic expression for calculating the target data amount is stored in accordance with the ratio (r) of the strong compression area, and each of the arithmetic expressions based on r without classifying slices. The target data amount of the slice may be calculated each time.

Further, in the present encoding device and the present encoding method, the calculation of the strong compression area is performed based on the angle information of the camera. For example, the calculation is performed using other information such as information extracted from the video signal. You may make it do.

This application claims the benefit of priority based on Japanese Patent Application No. 2018-044979 filed on March 13, 2018, the entire disclosure of which is incorporated herein by reference.

The present invention is suitable for a video encoding apparatus and a video encoding method capable of improving the image quality of a target imaging target even if there is a restriction on the amount of transmission data.

DESCRIPTION OF SYMBOLS 1 ... Coding part, 10,50 ... Video | video division | segmentation part, 11, 12, 13, 14, 15, 51, 52, 53, 54, 55 ... Coding process part, 16, 56 ... Data integration part, 17, 57 ... target data amount instruction unit, 18 ... strong compression area calculation unit, 19 ... target data amount calculation unit, 20 ... camera, 21 ... angle detection unit, 31 ... control unit, 32 ... I processing unit, 33 ... P processing unit, 34 ... selection unit, 35 ... buffer memory, 36 ... decoding unit

Claims

A video dividing unit for dividing the video signal from the camera into a plurality of slices;
A plurality of encoding processing units that are provided corresponding to the respective slices, perform encoding processing of the corresponding slices, and output compressed data;
A data integration unit that integrates the compressed data output from the plurality of encoding processing units and outputs the integrated compressed data;
A target data amount instruction unit that sets a target data amount that is a target amount of generated compressed data for each encoding processing unit,
The encoding processing unit generates compressed data within a range of a target data amount set from the target data amount instruction unit;
The target data amount instructing unit divides the upper limit value of the integrated compressed data amount by the number of slices and stores it as a basic target data amount, and detects a strong compression area with a small image change in the video signal Then, the ratio of the strongly compressed area in each slice is calculated, and a specific reduction amount is reduced from the basic target data amount and set as the target data amount of the encoding processing unit corresponding to the slice having the large proportion In addition, as the target data amount of the other encoding processing unit, the sum of the reduction amounts is divided by the number of the other encoding processing units and set in addition to the basic target data amount. Video encoding device.
When the target data amount instruction unit has a ratio of the strongly compressed area in the slice exceeding a preset threshold value, the target data amount instruction unit classifies the slice into the first class, and the ratio is equal to or less than the threshold value. If there is, classify the slice into the second class,
The target data amount of the encoding processing unit corresponding to the first class slice is set by reducing a specific reduction amount from the basic target data amount, and the encoding processing corresponding to the second class slice 2. The video according to claim 1, wherein the target data amount is set in addition to the basic target data amount by dividing the total of the reduction amounts by the number of slices classified into the second class. Encoding device.
The target data amount instructing unit stores a first reduction amount as a reduction amount and a second reduction amount that is smaller than the first reduction amount,
When the ratio of the strongly compressed area in the slice exceeds the first threshold, the slice is classified into the first class, and the ratio exceeds the second threshold and the first threshold is exceeded. If the threshold is less than or equal to the threshold, classify the slice into the second class; if the percentage is less than or equal to the second threshold, classify the slice into the third class;
The encoding process corresponding to the second class slice is set by setting the first reduction amount lower than the basic target data amount as the target data amount of the encoding processing unit corresponding to the first class slice. The target data amount of the first portion is set by reducing the second reduction amount from the basic target data amount, and the target data amount of the encoding processing unit corresponding to the slice of the third class is set as the first target data amount. The sum of the reduction amount and the sum of the second reduction amount are divided by the number of slices classified into the third class and set in addition to the basic target data amount. 1. The video encoding device according to 1.
The target data amount instruction unit calculates a reduction amount of the target data amount of the encoding processing unit corresponding to a slice having a large ratio of the strong compression area by an arithmetic expression based on the ratio. Video encoding device.
2. The video encoding apparatus according to claim 1, wherein the target data amount instruction section detects a strong compression area based on angle information of the camera angle, tilt, and zoom.
A video encoding method in a video encoding device that divides a video signal from a camera into a plurality of slices and encodes the slices by parallel processing,
The target data amount instruction unit divides the upper limit value of the integrated compressed data amount by the number of slices and stores it as a basic target data amount, and detects a strong compression area in which the image change in the video signal is small. The ratio of the strongly compressed area in each slice is calculated, and a specific reduction amount is reduced from the basic target data amount and set as the target data amount of the encoding processing unit corresponding to the slice having the large proportion. In addition, as the target data amount of the other encoding processing unit, the sum of the reduction amounts is divided by the number of the other encoding processing units and set in addition to the basic target data amount. Encoding method.