JP2018046407A - Rate control device, video decoding device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a bit rate adjustable while suppressing distortion of video due to video encoding.SOLUTION: A rate control device includes: a signal processing part for outputting a second video signal obtained by eliminating a specific component from a first video signal; and a control part for controlling the degree of elimination of the specific component by the signal processing part on the basis of a control signal relevant to at least either a bit rate of an encoded video signal obtained by encoding the second video signal and encoded distortion of a decoded video signal obtained by decoding the encoded video signal, and the signal processing part eliminates the specific component by a calculation different from one in an irreversible information compression process in encoding of the second video signal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for realizing bit rate control in video encoding, and an apparatus for decoding video from a bit string that is bit rate controlled.

  As a bit rate control method in video coding, generally, the quantization width (quantization parameter) of the orthogonal transform coefficient is increased or decreased according to the amount of generated code so far. For example, the following is known as a method for realizing a constant bit rate (CBR). First, an output buffer such as a FIFO (First In First Out) type memory is provided. This output buffer temporarily stores the encoded bit string and then outputs it. When the amount of data currently stored in the output buffer exceeds a predetermined upper limit threshold, the quantization parameter is increased. Further, when the amount of data currently stored in the output buffer exceeds a predetermined lower limit threshold, the quantization parameter is decreased. Thus, by controlling the video encoding process, it is possible to adjust the amount of generated code and realize a fixed bit rate.

  In video coding, if a video to be coded contains many fine textures, the amount of generated code tends to increase. In particular, a random texture such as noise significantly increases the amount of generated code. For this reason, it is possible to suppress the amount of generated codes by removing noise from the video to be encoded. However, if noise removal is performed before encoding, the video obtained by decoding is flattened, and the texture of the original video is impaired. As a method for compensating for this loss of texture, a decoding device and a decoding program of Patent Document 1 have been proposed.

Japanese Patent No. 5727872

  However, since the increase / decrease of the quantization parameter affects the occurrence of block distortion, in the case of the method of controlling the generated code amount by the increase / decrease of the quantization parameter as described above, in the case of video that is difficult to encode, block distortion In the case of a video that can be easily encoded, the block distortion is reduced. Since block distortion presents a rectangular conspicuous pattern, the increase and decrease of the distortion every moment becomes annoying. Therefore, it is desired to be able to adjust the bit rate while suppressing distortion of the video due to video coding.

  An object of some aspects of the present invention is to provide a rate control device, a video decoding device, and a program capable of adjusting a bit rate while suppressing video distortion due to video coding. I will.

  Another object of another aspect of the present invention is to provide a rate control device, a video decoding device, and a program that can achieve the effects described in the embodiments described later.

In order to solve the above-described problem, according to one embodiment of the present invention, a signal processing unit that outputs a second video signal obtained by removing a specific component from a first video signal, and the second video signal are encoded. The signal processing unit removes a specific component based on a control signal related to at least one of the bit rate of the encoded video signal and the encoding distortion of the decoded video signal obtained by decoding the encoded video signal. A control unit that controls the degree, and the signal processing unit is a rate control device that removes the specific component by an operation different from an irreversible information compression process in encoding the second video signal. .
Another aspect of the present invention is the rate control device described above, wherein the specific component is a noise component, and the signal processing unit is a median filter or a low-frequency filter whose removal intensity is variable depending on a parameter. The noise component is removed using a pass filter.
One embodiment of the present invention is the rate control device described above, further including a calculation unit that calculates a removal amount of a specific signal component by the signal processing unit.
One aspect of the present invention is the rate control device described above, further including a storage unit that temporarily stores the encoded video signal, wherein the control signal is the encoded video signal generated by the storage unit. Is a signal related to the accumulated amount of.
According to another aspect of the present invention, a signal generation unit that generates a signal of a specific component based on the removal amount of the specific component calculated by the rate control device, and a video that decodes the encoded video signal A video decoding apparatus comprising: a decoding unit; and a superimposing unit that superimposes the signal generated by the signal generating unit on the decoded video signal decoded by the video decoding unit.
In one embodiment of the present invention, a first step of outputting a second video signal obtained by removing a specific component from the first video signal to a computer, and an encoded video obtained by encoding the second video signal Degree of removal of the specific component from the first video signal based on a control signal according to at least one of a bit rate of the signal and a coding distortion of the decoded video signal obtained by decoding the coded video signal A program for executing the second step of controlling the specific component by the calculation different from the irreversible information compression process in the encoding of the second video signal in the first step. The program to be removed.
According to another aspect of the present invention, a computer includes a first step of generating a signal of a specific component based on the removal amount of the specific component calculated by the rate control device, and the encoded video signal. A program for executing a second step of decoding and obtaining a decoded video signal, and a third step of superimposing the signal generated in the first step on the decoded video signal decoded in the second step. .

  According to one embodiment of the present invention, it is possible to adjust the bit rate while suppressing distortion of video due to video coding.

It is a block diagram which shows the structure of the video coding / decoding system which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the rate control apparatus which concerns on the same embodiment. It is a block diagram which shows the structure of the video decoding apparatus which concerns on the same embodiment. It is a block diagram which shows the structure of the rate control apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the video decoding apparatus which concerns on the same embodiment. It is a block diagram which shows the structure of the rate control apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the rate control apparatus which concerns on the 4th Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First embodiment]
A first embodiment of the present invention will be described.
First, the configuration of the video encoding / decoding system 1 will be described.
The video encoding / decoding system 1 according to the present embodiment includes MPEG-4 AVC / H. H.264 and MPEG-H HEVC / H.264. This is a system for encoding / decoding video by a video encoding method such as H.265. Note that the type of video encoding method is arbitrary, and may be lossless encoding or lossy encoding.

FIG. 1 is a block diagram showing a configuration of a video encoding / decoding system 1 according to the present embodiment.
The video encoding / decoding system 1 includes a rate control device 10, a video encoding device 30, a transmission storage unit 50, and a video decoding device 70. The rate control device 10, the video encoding device 30, and the video decoding device 70 are electronic devices including a computer system, for example.

  The rate control device 10 is a device that is communicably connected to the video encoding device 30 and controls the bit rate of compression encoding of the video signal by the video encoding device 30. The rate control apparatus 10 removes a specific component from the video signal to be encoded (input video signal). The specific component is a component related to at least one of frequency, wavelength, amplitude, and phase. In the present embodiment, as an example, the specific component is described as a high-frequency noise component.

  The rate control device 10 controls the degree of noise component removal from the video signal (hereinafter referred to as “removal degree”) in accordance with a predetermined control signal. Thereby, in the rate control apparatus 10, the predetermined control signal is a parameter related to at least one of the bit rate of the encoded video signal and the encoding distortion of the decoded video signal.

  The rate control device 10 outputs a video signal from which a specific component is removed (hereinafter referred to as “noise-removed video signal”) to the video encoding device 30. The rate control device 10 controls the bit rate of video signal encoding by adjusting the degree of difficulty in encoding video signals by adjusting the degree of removal of noise components. If the degree of removal is increased, the criticality of the video signal is reduced, so that the amount of code generated by video coding can be relatively reduced, and if the degree of removal is reduced, the criticality of the video signal is increased. The generated code amount of encoding can be made relatively large. Thereby, the rate control apparatus 10 can implement | achieve a fixed bit rate. However, the rate control apparatus 10 may use a variable bit rate (VBR, Variable Bit rate) instead of a fixed bit rate, or an average bit rate (AVR, Avertate Bitrate).

  The video encoding device 30 compresses and encodes the noise-removed video signal from the rate control device 10. The video encoding device 30 outputs a bit string of a compression-encoded video signal (hereinafter referred to as “encoded video signal”) to the rate control device 10.

  The rate control device 10 acquires a bit string of the encoded video signal from the video encoding device 30. The rate control apparatus 10 temporarily accumulates the acquired bit sequence of the encoded video signal and outputs it to the transmission accumulation unit 50 while maintaining the order of the bit sequence. In the present embodiment, as an example, the above control signal is described as a parameter related to the accumulation amount of the bit string of the encoded video signal by the rate control device 10. That is, the rate control apparatus 10 controls the removal degree of the noise component according to the accumulation amount of the bit string of the encoded video signal.

  The transmission storage unit 50 transmits or stores a bit string of an encoded video signal, that is, a code. The transmission storage unit 50 performs transmission path encoding and signal modulation on the video encoding device 30 side as necessary. Then, the transmission storage unit 50 performs signal transmission through a transmission line that is wireless, wired, or a combination thereof. On the video decoding device 70 side of the transmission storage unit 50, demodulation and transmission path decoding are performed as necessary, and a code is output. The transmission storage unit 50 may perform encryption, add an electronic signature, or multiplex or demultiplex with other signals. In addition, the transmission storage unit 50 may perform distribution, exchange, remodulation, delay, amplification, and the like in the middle of the transmission path.

  Further, when accumulating codes, the transmission accumulating unit 50 stores the acquired codes in a storage medium. The transmission storage unit 50 may output the code simultaneously with the storage of the code, or may read and output the code once stored. The transmission storage unit 50 may perform encoding or encryption with an error correction code or the like, addition of an electronic signature, or the like when storing the acquired code in a storage medium. This storage medium may be a solid-state memory or a magnetic or optical recording medium.

Further, the transmission storage unit 50 may be configured to combine transmission and storage. In this case, the transmission storage unit 50 transmits the code to a remote storage medium, such as a so-called cloud, and stores the code in the remote storage medium. Then, the transmission storage unit 50 transmits the code to the video decoding device 70 simultaneously with the storage of the code, reads the code once stored, and outputs the code to the video decoding device 70.
Here, it is assumed that the transmission storage unit 50 does not cause a signal error or signal degradation in the process of transmission and storage. That is, the transmission accumulation unit 50 outputs the code acquired from the rate control device 10 to the video decoding device 70 as it is.

The video decoding device 70 acquires a code, that is, a bit string of the encoded video signal, from the transmission storage unit 50. The video decoding device 70 decodes the bit string of the acquired encoded video signal. The video decoding device 70 outputs the decoded video signal (hereinafter referred to as “decoded video signal”) to, for example, a video playback device.
The above is the description of the configuration of the video encoding / decoding system 1.

Next, the configuration of the rate control device 10 will be described.
FIG. 2 is a block diagram showing a configuration of the rate control apparatus 10 according to the present embodiment.
The rate control device 10 includes a noise removing unit 11, a transmission buffer 12, and a control unit 13. The noise removal unit 11, the transmission buffer 12, and the control unit 13 may be implemented by executing a program stored in the storage unit by a CPU (Central Processing Unit) of the rate control apparatus 10, or may be implemented by an LSI (Large). It may be implemented as an integrated circuit such as a scale integration (ASIC) or an application specific integrated circuit (ASIC).

  The noise removing unit 11 removes noise components from the input video signal to generate a noise-removed video signal. The noise removal unit 11 outputs a noise removal video signal to the video encoding device 30. The degree of removal of noise components by the noise removing unit 11 is variable. The noise removal unit 11 changes the removal degree of the noise component according to a control signal c acquired from the control unit 13 described later.

  The noise component includes thermal noise generated in an image sensor or circuit, shot noise caused by light particle characteristics when the amount of light is small, and dot-like or linear image signal patterns due to pixel defects of the image sensor (so-called This refers to a minute disturbance of pixel values (for example, a connected region of about 1 to 10 pixels, or about 1 line or 1 column) that deviates from the original image of the subject, such as white and black. The removal of the noise component refers to an operation for removing a specific waveform component of the video signal waveform by an operation different from an irreversible information compression process (for example, quantization of orthogonal transform coefficients) in video coding. Shall.

Here, a specific example of noise component removal by the noise removal unit 11 will be described.
For example, the noise removing unit 11 processes the frame I of the input video signal. The pixel value at the image coordinates [x, y] ^T of the frame I is defined as a pixel value I ([x, y] ^T ). A superscript T represents transposition of a matrix or a vector. That is, the image coordinates ([x, y] ^T ) are image coordinates expressed by a column vector. Noise removal unit 11 removes the noise components according to the parameter p indicating the removal of the noise component, to generate a noise cancellation video signal J _p. Then, the noise removal unit 11 outputs the noise removal video signal _Jp to the video encoding device 30.
For example, the noise removal unit 11, the following equation (1) is converted by calculation of (2), the frame I to the frame J _p denoising video signal.

  Here, med is the median calculation, and the region K is the coordinate range for which the median is to be obtained. Hereinafter, the image M is referred to as a median image. For example, the region K may be set as shown in the following formula (3).

  That is, the region K can be a set of lattice points within a circle (including the circumference) having a radius of 1 at the Chebyshev distance. The region K may be set by the Euclidean distance or the Manhattan distance instead of the Chebyshev distance. The region K may be other than a circle, and in the case of a circle, the radius may be a positive real number other than 1 (assumed to be 1 or more). The parameter p is a real number, and may be a value between 0 and 1 (0 ≦ p ≦ 1), for example. In this case, in Formula (1), the larger the value of the parameter p, the greater the effect of noise removal by the median processing.

  The noise removal unit 11 changes the removal degree of the noise component according to the value of the control signal c from the control unit 13. For example, as shown in the following equation (4), the parameter p is sequentially updated using the real constant a and the real constant b in accordance with the value of the control signal c.

  In Expression (4), an arrow (←) indicates that the left side value is sequentially updated with the right side value. The sequential update timing is, for example, in units of frames. The real constant a may be “−1” or more and less than zero (−1 ≦ a <0). The real constant b may be (0 <b ≦ + 1). For example, the values of the real constants a and b may be set as in the following formulas (5) and (6).

  Note that the noise component removing method by the noise removing unit 11 is not limited to the above-described median calculation. For example, the noise removal unit 11 may remove the noise component using a low-pass filter. In this case, for example, the cutoff frequency of the low-pass filter may be controlled by the parameter p. In this case, the cutoff frequency may be decreased as the parameter p is increased. For example, the dispersion value of the low-pass filter using a Gaussian filter may be controlled according to the parameter p. In this case, the variance value may be increased as the parameter p is increased.

  The transmission buffer 12 is a memory that temporarily stores a bit string of the encoded video signal acquired from the video encoding device 30. For example, the transmission buffer is a FIFO type memory. The transmission buffer 12 sequentially outputs the bit strings held in the memory at appropriate timing while maintaining the order. Here, the appropriate timing may be a constant bit rate, for example, or may be a timing according to the data congestion status of the transmission storage unit 50.

Further, the transmission buffer 12 outputs untransmitted amount information to the control unit 13.
The untransmitted amount information is information relating to the total amount of unsent data accumulated in the transmission buffer 12. For example, the untransmitted amount information may be information indicating the amount of untransmitted data stored in the transmission buffer 12, or the amount of untransmitted data stored in the transmission buffer 12. May be flag information indicating whether one or more threshold values are exceeded. Hereinafter, as an example, the description will be made assuming that the untransmitted amount information is information indicating the amount of untransmitted data accumulated in the transmission buffer 12. Also, the amount of untransmitted data accumulated in the transmission buffer 12 will be described as an untransmitted data amount u, and the maximum capacity that can be stored in the transmission buffer will be described as a capacity B.

The control unit 13 generates a control signal c for controlling the noise removal unit 11 described later according to the amount of untransmitted data amount u.
For example, the control signal c takes three values according to the increase / decrease in the untransmitted data amount u. Specifically, the control signal c is “1” (c = 1) when increasing, “0” (c = 0) when holding, and “−1” (c = −1) when decreasing. In another example, when there is no untransmitted data amount u (u = 0), the control signal c is set to “1” (c = −1), and the untransmitted data amount u is equal to or less than a predetermined threshold k · B. In the case (0 <u ≦ k · B), the control signal c is set to “0” (c = 0), and the untransmitted data amount u is larger than a predetermined threshold (u> kB), the control signal c is set to “1”. (C = 1). At this time, the coefficient k is a real constant greater than 0 and less than or equal to 1 (0 <k ≦ 1). For example, the value of the coefficient k may be “0.8” (k = 0.8).
The above is the description of the configuration of the rate control device 10.

Here, a specific example of control of the degree of noise removal when the value of the coefficient k is “0.8” (k = 0.8) will be described. When the transmission buffer 12 is empty (u = 0), the control signal c is “−1” (c = −1), and the control unit 13 sets the noise removal unit 11 so that the noise component removal degree is lowered. Control. As a result, the amount of generated code is increased and the deterioration of the video is suppressed. When the untransmitted data amount u exceeds 80% of the capacity B of the transmission buffer 12 (u> kB), the control signal c becomes “1” (c = 1), and the control unit 13 removes the noise component. The noise removing unit 11 is controlled so as to increase the degree. As a result, the generated code amount decreases. In other cases (0 <u ≦ k · B), the control unit 13 controls the noise removal unit 11 so that the noise component removal degree is maintained as it is.
The above is the description of the specific example of the control of the noise removal degree when the value of the coefficient k is “0.8” (k = 0.8).

Next, the configuration of the video decoding device 70 will be described.
FIG. 3 is a block diagram illustrating a configuration of the video decoding device 70.
The video decoding device 70 includes a video decoding unit 71.
The video decoding unit 71 is configured to make a pair with the video encoding device 30 (video encoding unit). The video decoding unit 71 acquires a bit string of the encoded video signal output from the rate control device 10 via the transmission storage unit 50. The video decoding unit 71 decodes the encoded video signal and generates a decoded video signal R. The video decoding unit 71 outputs the decoded video signal R to a display device or the like.
The above is the description of the configuration of the video decoding device 70.

  The conventional rate control apparatus adjusts the bit rate by changing the quantization parameter according to the amount of generated code. For this reason, in the conventional rate control apparatus, the block distortion increases or decreases between frames, which is easily noticeable.

  On the other hand, the rate control apparatus 10 according to the present embodiment has a second video signal (for example, noise) obtained by removing a specific component (for example, noise component) from the first video signal (for example, input video signal). A noise removal unit 11 that outputs a (removed video signal) and a control signal related to the bit rate of the encoded video signal obtained by encoding the second video signal. And a noise removal unit 11 that removes the specific component by an operation different from the irreversible information compression process in the encoding of the second video signal.

  That is, the rate control apparatus 10 suppresses the generated code amount by removing a specific component from the input video signal. Also, the rate control apparatus 10 adjusts the generated code amount by controlling the degree of removal of a specific component in accordance with the amount of generated code. Therefore, the rate control apparatus 10 does not increase or decrease the block distortion due to the increase or decrease of the quantization parameter between frames while controlling the bit rate. Therefore, the rate control device 10 can adjust the bit rate while suppressing distortion of video due to video encoding. In other words, the video encoding / decoding system 1 does not make temporal changes in image quality caused by rate control conspicuous like block distortion. Can be improved.

In the rate control apparatus 10, the specific component is a noise component, and the noise removal unit 11 uses a median filter or a low-pass filter whose removal intensity is variable according to a parameter. Remove.
Since the noise component is a minute disturbance of the pixel value that is deviated from the original image of the subject, it can be removed by a median filter or a low-pass filter. Therefore, the rate control apparatus 10 can perform rate control while maintaining the video quality, as compared with the case where the generated code amount is adjusted by changing the quantization parameter.

Further, the rate control apparatus 10 includes a transmission buffer 12 that temporarily stores the encoded video signal, and the control signal is a storage amount of the encoded video signal by the transmission buffer 12 (for example, untransmitted). This is a signal related to the data amount u).
That is, the rate control apparatus 10 controls the degree of removal of a specific component according to the generated code amount of the encoded video signal and the data congestion status of the transmission storage unit 50. Therefore, the rate control device 10 can adjust the bit rate while suppressing distortion of video due to video encoding.

[Second Embodiment]
A second embodiment of the present invention will be described. Here, about the structure similar to embodiment mentioned above, the same code | symbol is attached | subjected and description is used.
A video encoding / decoding system 1 </ b> A (not shown) according to the present embodiment is a system that encodes and decodes video in the same manner as the video encoding / decoding system 1. However, the video encoding / decoding system 1A calculates the amount (removal amount) of the noise component removed from the input video signal, and adds noise corresponding to the removal amount at the time of decoding. Thereby, the texture of the input video signal can be reproduced at the time of decoding while suppressing the generated code amount at the time of encoding.

Next, the configuration of the video encoding / decoding system 1A will be described.
The video encoding / decoding system 1A includes a rate control device 10A and a video decoding device 70A instead of the rate control device 10 and the video decoding device 70 included in the video encoding / decoding system 1.

FIG. 4 is a block diagram showing the configuration of the rate control apparatus 10A.
The rate control device 10A includes a noise power calculation unit 14A and a multiplexing unit 15A in addition to the various configurations included in the rate control device 10.
The noise power calculation unit 14A compares the video frames between the input video signal and the noise-removed video signal, and quantifies the removal amount of the noise component. For example, the noise power calculation unit 14A includes a frame I of the input video signal, based on the frame J _p denoising video signal, calculates the noise power P. Then, the noise power calculation unit 14A outputs information indicating the noise power P (that is, information regarding the removal amount) to the multiplexing unit 15A. The information regarding the removal amount is information for compensating for a change in image quality accompanying removal of a noise component at the time of decoding. The noise power P is calculated by the following equation (7), for example.

  The multiplexing unit 15A outputs the bit sequence obtained by multiplexing the bit sequence of the encoded video signal read from the transmission buffer 12 and the information regarding the removal amount acquired from the noise power calculation unit 14A to the transmission storage unit 50. The multiplexing unit 15A may multiplex the information regarding the removal amount as it is, or may multiplex after multiplexing. Further, the multiplexing unit 15A may multiplex the information regarding the removal amount after predictive encoding or entropy encoding, or may entropy encode and multiplex after predictive encoding.

FIG. 5 is a block diagram showing a configuration of the video decoding device 70A.
The video decoding device 70A includes a demultiplexing unit 72A, a noise generating unit 73A, and a superimposing unit 74A in addition to the various configurations included in the video decoding device 70.
The demultiplexing unit 72A separates the bit sequence of the encoded video signal and the information regarding the removal amount of the noise component from the bit sequence multiplexed by the multiplexing unit 15A of the rate control apparatus 10A. The demultiplexing unit 72A outputs the separated encoded video signal bit string to the video decoding unit 71. In addition, the demultiplexing unit 72A outputs information on the noise component removal amount to the noise generating unit 73A.

  The noise generation unit 73A acquires information on the amount of noise component removal from the demultiplexing unit 72A. The noise generation unit 73A generates a noise signal N based on information regarding the removal amount of the noise component. For example, the noise generation unit 73A generates noise having a variance value corresponding to the noise power P, and uses the noise as a noise signal N. The noise generating unit 73A generates, for example, Gaussian noise. The noise generation unit 73A outputs the generated noise signal N to the superposition unit 74A.

  The superimposing unit 74A acquires the decoded video signal R from the video decoding unit 71. The superimposing unit 74A acquires the noise signal N from the noise generating unit 73A. The superimposing unit 74A superimposes the decoded video signal R and the noise signal N and outputs the result as an output video signal O. For example, the superimposing unit 74A may perform superimposition by adding the decoded video signal R and the noise signal N as shown in the following equation (8).

The above is the description of the configuration of the video encoding / decoding system 1A.
As described above, the rate control apparatus 10A includes the noise power calculation unit 14A that calculates the amount of removal of a specific signal component (for example, noise component) by the noise removal unit 11.
The video decoding device 70A also includes a noise generating unit 73A that generates a signal of a specific component based on the removal amount of the specific component calculated by the rate control device 10A, and a video decoding that decodes the encoded video signal. And a superimposing unit 74A that superimposes the signal generated by the signal generating unit on the decoded video signal decoded by the decoding unit.

  That is, the rate control apparatus 10A specifies the amount of the component removed from the input video signal. For example, the rate control apparatus 10A can add and transmit information for compensating for a change in image quality accompanying an increase or decrease in the amount of noise together with a bit string of an encoded video signal. Then, the video decoding device 70A adds the amount of components removed by the rate control device 10A to the decoded video signal. That is, the video decoding device 70A can compensate for the amount of noise removed before encoding, for example, for the encoded video signal. Accordingly, the video encoding / decoding system 1A can suppress a change in temporal texture of the video due to noise removal processing and encoding / decoding processing, and can improve subjective image quality.

[Third Embodiment]
A third embodiment of the present invention will be described. Here, about the structure similar to embodiment mentioned above, the same code | symbol is attached | subjected and description is used.
A video encoding / decoding system 1B (not shown) according to the present embodiment is a system that encodes and decodes video, similarly to the video encoding / decoding system 1A, and adds noise according to the removal amount during decoding. However, the video coding / decoding system 1A calculates the removal amount by comparing the input video signal with the noise-removed video signal, whereas the video coding / decoding system 1B has the input video signal, the decoded video signal, The difference is that the removal amount is calculated by comparing the two.

Next, the configuration of the video encoding / decoding system 1B will be described.
The video encoding / decoding system 1B includes a rate control device 10B instead of the rate control device 10A included in the video encoding / decoding system 1A.
FIG. 6 is a block diagram showing the configuration of the rate control device 10B.
The rate control device 10B includes a video decoding unit 16B in addition to the various configurations included in the rate control device 10A.

The video decoding unit 16B has the same configuration as the video decoding unit 71. The video decoding unit 16B outputs the decoded video signal to the noise power calculation unit 14A.
The noise power calculation unit 14A according to the present embodiment calculates the noise power P using the frame of the decoded video signal acquired from the video decoding unit 16B instead of the frame of the noise-removed video signal. Accordingly, the video decoding device 70A can add noise corresponding to the removal amount of the noise component to the decoded video signal.
The above is the description of the configuration of the video encoding / decoding system 1B.

  As described above, the rate control apparatus 10B may specify the amount of the specific component to be added at the time of decoding by comparing the input video signal and the video signal after the encoding / decoding process.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described. Here, about the structure similar to embodiment mentioned above, the same code | symbol is attached | subjected and description is used.
A video encoding / decoding system 1 </ b> C (not shown) according to the present embodiment is a system that encodes and decodes video as in the video encoding / decoding system 1. However, while the video encoding / decoding system 1 controls the degree of noise component removal from the input video signal based on the untransmitted data amount u of the transmission buffer 12, the video encoding / decoding system 1C The difference is that the degree of removal of the noise component is controlled based on the coding distortion of the video signal.

Next, the configuration of the video encoding / decoding system 1C will be described.
The video encoding / decoding system 1C includes a rate control device 10C instead of the rate control device 10 included in the video encoding / decoding system 1.
FIG. 7 is a block diagram showing the configuration of the rate control device 10C.
The rate control device 10C includes a control unit 13C instead of the control unit 13 included in the rate control device 10. Further, the rate control apparatus 10C includes a video decoding unit 16B in addition to the various configurations included in the rate control apparatus 10.

The control unit 13C determines the control signal c based on the coding distortion instead of the untransmitted data amount u of the transmission buffer 12. The control unit 13C may calculate the encoding distortion by an arbitrary method. For example, the control unit 13C may calculate the coding distortion by comparing the noise-removed video signal and the decoded video signal. Specifically, the coding distortion may be calculated using a distortion evaluation function in HEVC Test Model. Then, for example, when the coding distortion is large, the control unit 13C sets the value of the control signal c to “−1” (c = −1), and when the coding distortion is small, the value of the control signal c. May be set to “1” (c = 1). Accordingly, the video decoding device 70A can control the degree of noise component removal based on the coding distortion.
The above is the description of the configuration of the video encoding / decoding system 1C.

  In this way, the rate control apparatus 10C may control the degree of removal of a specific component according to the degree of coding distortion, in addition to the untransmitted data amount u of the transmission buffer 12. Also in this case, the rate control apparatus 10C can adjust the bit rate while suppressing the distortion of the video due to the video encoding.

[Modification]
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above-described embodiment, and includes a design and the like within a scope not departing from the gist of the present invention. For example, the configurations described in the first to fourth embodiments can be arbitrarily combined. In addition, for example, each configuration described in the above first to fourth may be separately provided in a separate device.
For example, the control signal c may be determined based on both the untransmitted data amount u of the transmission buffer 12 described in the first embodiment and the encoding distortion described in the fourth embodiment. For example, the control signal c may be determined based on an RD (Rate-Distortion) cost.

  Further, a program for realizing the functions of the rate control devices 10, 10A, 10B, 10C, the video encoding device 30, and the video decoding devices 70, 70A described above is recorded on a computer-readable recording medium. The programs recorded in the above may be read into a computer system and executed to perform processing as the rate control devices 10, 10A, 10B, and 10C, the video encoding device 30, and the video decoding devices 70 and 70A. Here, “loading and executing a program recorded on a recording medium into a computer system” includes installing the program in the computer system. The “computer system” here includes an OS and hardware such as peripheral devices. Further, the “computer system” may include a plurality of computer devices connected via a network including a communication line such as the Internet, WAN, LAN, and dedicated line. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. As described above, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM. The recording medium also includes a recording medium provided inside or outside that is accessible from the distribution server in order to distribute the program. The code of the program stored in the recording medium of the distribution server may be different from the code of the program that can be executed by the terminal device. That is, the format stored in the distribution server is not limited as long as it can be downloaded from the distribution server and installed in a form that can be executed by the terminal device. Note that the program may be divided into a plurality of parts, downloaded at different timings, and combined in the terminal device, or the distribution server that distributes each of the divided programs may be different. Furthermore, a “computer-readable recording medium” holds a program for a certain period of time, such as a volatile memory (RAM) inside a computer system that becomes a server or client when the program is transmitted via a network. Including things. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiments of the present invention have been described in detail above with reference to the drawings. However, the specific configuration is not limited to the above-described one, and various design changes and the like can be made without departing from the scope of the present invention. Is possible.

  DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Video coding / decoding system 10, 10A, 10B, 10C ... Rate control device, 30 ... Video coding device, 50 ... Transmission storage unit, 70, 70A ... Video decoding device, 11 ... Noise Removal unit, 12 ... transmission buffer, 13, 13C ... control unit, 14A ... noise power calculation unit, 15A ... multiplexing unit, 16B ... video decoding unit, 71 ... video decoding unit, 72A ... demultiplexing unit, 73A ... noise Generation part, 74A ... Superimposition part

Claims (7)

A signal processing unit that outputs a second video signal obtained by removing a specific component from the first video signal;
The signal based on a control signal according to at least one of a bit rate of an encoded video signal obtained by encoding the second video signal and an encoded distortion of a decoded video signal obtained by decoding the encoded video signal. A control unit that controls the degree of removal of a specific component by the processing unit;
With
The signal processing unit removes the specific component by an operation different from an irreversible information compression process in encoding of the second video signal. The specific component is a noise component,
The rate control apparatus according to claim 1, wherein the signal processing unit removes the noise component using a median filter or a low-pass filter whose removal intensity is variable according to a parameter. A calculation unit for calculating a removal amount of a specific signal component by the signal processing unit;
The rate control apparatus according to claim 1 or 2, further comprising: A storage unit for temporarily storing the encoded video signal;
The control signal is a signal related to an accumulation amount of the encoded video signal by the accumulation unit.
The rate control apparatus as described in any one of Claims 1-3. A signal generation unit that generates a signal of a specific component based on the removal amount of the specific component calculated by the rate control device according to claim 3;
A video decoding unit for decoding the encoded video signal;
A superimposing unit that superimposes the signal generated by the signal generating unit on the decoded video signal decoded by the video decoding unit;
A video decoding device comprising: On the computer,
A first step of outputting a second video signal obtained by removing a specific component from the first video signal;
Based on a control signal according to at least one of a bit rate of an encoded video signal obtained by encoding the second video signal and an encoding distortion of a decoded video signal obtained by decoding the encoded video signal. A second step of controlling the degree of removal of a specific component from one video signal;
A program for executing
In the first step, the specific component is removed by an operation different from an irreversible information compression process in the encoding of the second video signal. On the computer,
A first step of generating a signal of a specific component based on the removal amount of the specific component calculated by the rate control device according to claim 3;
A second step of decoding the encoded video signal to obtain a decoded video signal;
A third step of superimposing the signal generated in the first step on the decoded video signal decoded in the second step;
A program for running

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