JPH10294936A - Remaining buffer capacity limit processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remaining buffer capacity limit processor which improves the degradation of picture quality after the limitation of remaining buffer capacity. SOLUTION: A remaining capacity limiting range detecting means 11 detects a remaining capacity limiting range as the range to limit remaining buffer capacity. A distribution ratio calculating means 12 calculates a distribution ratio so that the distribution ratio of bit amount to respective pictures in the remaining capacity limiting range can be equal with the ratio before the remaining capacity is limited. Based on the distribution ratio, a bit amount calculating means 13 calculates the amount of bits to be distributed to the pictures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer remaining amount limiter, and more particularly to a buffer remaining amount limiter which distributes the amount of bits stored in the buffer to pictures when encoding a video signal so that the bit amount does not fall below a certain value. And a buffer remaining amount processing device that performs

[0002]

2. Description of the Related Art One of the important factors for the spread of multimedia services is the creation of multimedia applications. Multimedia applications are generally created by using authoring tools to combine content, such as video and audio.

[0003] In addition, since it is difficult to newly create the content itself, a service for providing only a content such as a photo book or a video book has appeared, so that the user can freely use and process the content.

In an encoding authoring system that creates a multimedia application by compressing and editing information from such contents, DVD, Video,
The compressed video signal such as oCD is information-compressed, edited, and stored in a package medium such as a CDROM or a file.

[0005] The encoding process first distributes information such as image complexity (hereinafter referred to as Difficulty). Further, the user evaluates (previews) the image quality of the encoding result. In addition, if necessary, a bit distribution amount is adjusted or a customizing operation for applying a filter is performed. As described above, the encoding work is performed while repeating the customization / preview.

In MPEG video encoding, bits are distributed to pictures in consideration of a virtual remaining buffer capacity of a decoder. This buffer remaining amount calculation is called VBV (Video_Buffering_Verifier).

In the VBV calculation process, if there are many bits to be distributed to pictures (hereinafter referred to as target bits), the amount of data stored in the buffer is reduced.
The target bit amount must be limited so that the buffer remaining amount does not fall below a certain value. On the other hand, when the buffer becomes full, the supply of data from the pickup of the decoder is stopped, so that it is not necessary to particularly consider the overflow.

[0008]

However, in the conventional VBV calculation processing as described above, when encoding under a high bit rate condition, the target bit amount is relatively relative to the bit amount given to the buffer. growing.

Then, the target bit amount must be limited for each picture, and the ratio of the bit amount for each picture changes. Therefore, since the original bit ratio is distributed according to the Difficulty of the image, there is a problem that if the ratio changes significantly, the bit cannot be distributed according to the Difficulty.

[0010] Normally, the I picture has the largest Difficulty value in the GOP, and the target bit amount also increases accordingly. However, at the time of VBV restriction, the probability of bit reduction for a picture having a large target bit amount is high, and as a result, the ratio of I-pictures in a GOP decreases. For this reason, there is a problem that the target bit amount of the I picture cannot be given sufficiently, and thus the image quality degradation spreads in the GOP.

SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to provide a buffer remaining amount processing apparatus in which image quality deterioration after VBV restriction is improved.

[0012]

In order to solve the above-mentioned problems, the remaining amount of the buffer is limited so that the amount of bits stored in the buffer does not fall below a certain value when the video signal is distributed to pictures. In the buffer remaining amount limit processing device, a remaining amount limited range detecting unit that detects a remaining amount limited range in which the buffer remaining amount is limited, and a distribution ratio of a bit amount to each picture within the remaining amount limited range is determined. Distribution ratio calculating means for calculating a distribution ratio so as to be equal to that before performing the remaining amount limitation, and bit amount calculating means for calculating the bit amount to be distributed to pictures based on the distribution ratio, There is provided a buffer remaining amount limit processing device.

Here, the remaining amount limit range detecting means detects a remaining amount limit range in which the buffer remaining amount is limited. The distribution ratio calculation means calculates the distribution ratio such that the distribution ratio of the bit amount to each picture within the remaining amount limit range becomes equal to that before the remaining amount is limited. The bit amount calculating means calculates a bit amount to be distributed to the picture based on the distribution ratio.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the principle of a buffer remaining amount processing device according to the present invention. Remaining amount limit range detecting means 11
Detects a remaining amount limit range in which the buffer remaining amount is limited. The distribution ratio calculating means 12 calculates the distribution ratio such that the distribution ratio of the bit amount to each picture within the remaining amount limit range becomes equal to that before the remaining amount is limited. The bit amount calculation means 13 calculates the bit amount to be distributed to the picture based on the distribution ratio. The detailed operation will be described later.

Next, the overall configuration of the MPEG video encoding system will be described. FIG. 2 is an overall view of the MPEG video encoding system. Supervisor device 300 and PC (personal computer) 10 via network 200
0 connects. The PC 100 has a VTR 500 and MP
EG encoder 400 is connected and MPEG encoder 4
00 is connected to a monitor 410.

The supervisor device 300 manages the entire authoring system, gives an encoding condition to the PC 100, and receives a report of the encoding result from the PC 100. In the figure, video encoding conditions are input by a file called v.enc. The PC 100 reports an address v.adr at which the bit stream of the encoding result is written on the hard disk, and data vxxx.aui necessary for multiplexing the bit stream. (Xxx indicates the ENCU number.) The GUI 101 is the encoding control program 10
2. It manages three programs: a bit distribution program 103 and a VTR control program 104.

Next, the GOP structure will be described. FIG. 3 shows the GOP structure. DVD adopts MPEG as a video compression method. In MPEG, the temporal redundancy is removed by motion compensation prediction, and three picture types are defined in order to realize this prediction encoding.

A picture coded only in a frame is an I picture, a picture coded by predicting the current from a past screen is a P picture, and a picture coded by predicting the current from a past or future image. Is called a B picture. A group of pictures that always includes one I picture is called a GOP. When coding, the I and P pictures are processed first, and the intervening B pictures are processed later.

Next, a description will be given of an encoding operation process when the user performs encoding. FIG. 4 is a flowchart showing the encoding operation process. Note that the steps in the bold frame in the figure correspond to the offline processing on the computer. [S1] Encoding conditions such as the total amount of bits and the maximum rate allocated to video via the network 200 from the supervisor apparatus 300 described in FIG. 2 are set. [S2] After setting the encoding conditions, the Diff
Measure iculty. Here, the amount of generated bits is measured under the condition that the number of quantization steps is set to a fixed value at the time of encoding. For images with lots of motion and large high frequency components,
The generated bit amount increases, and the generated bit amount decreases in a still image or an image having many flat portions. The magnitude of this generated bit amount is measured as Difficulty of the image. [S3] Difficul of each picture based on encoding conditions
A distribution calculation of the target bit amount is performed according to the size of ty. [S4] A preview is performed based on the image quality of the output of the local decoder built in the encoder to determine whether to execute the encoding using the result of the bit distribution. [S5] According to the image quality evaluation by the preview, if there is a problem with the image quality, the process proceeds to step S6, and if there is no problem, the process proceeds to step S8. [S6] A customizing operation is performed. For example, the rate of a portion having a problem in image quality is increased, or the filter level is adjusted. [S7] The bit distribution is recalculated, and the process returns to step S4. [S8] The entire encoding is executed. [S9] Post-processing is performed. For example, a bit stream as an encoding result is directly written to the RAID which is a server of the authoring system via SCSI. Also, the encoding result information is transferred to the supervisor device 30 described in FIG.
0 via the network 200.

Next, the bit distribution calculation will be described. FIG. 5 is a diagram showing a process in the bit distribution calculation. First, the authoring system specifies the total bit amount (QTY_BYTES) and the maximum bit rate (MAXRATE) allocated to the video from the disk capacity.

On the other hand, the total number of bits (USB_BYTES) limited so as to be equal to or less than the maximum bit rate is obtained. The calculation formula is shown in formula (1). Note that FW in the expression is the number of frames per second, which is 29.97 for NTSC and 25 for PAL.

[0022]

[Expression 1] USB_BYTES = min (QTY_BYTES, MAXRATE / 8 / FW * TOTAL_FRAME_NB) (1) From this value, the number of bits required for GOP HEADER (TOTAL_HEAD)
From the value obtained by subtracting ER) and the total number of frames, SUPPLY_BYTES which is the target value of the total number of targets is calculated. The calculation formula is shown in formula (2).

[0023]

## EQU2 ## SUPPLY_BYTES = USB_BYTES-HEADER (2) The amount of bits (target amount) allocated to each picture is distributed so as to be within the size of SUPPLY_BYTES. TARGET_BYTES sums the total amount of bits allocated to all pictures
Then, the value obtained by subtracting TARGET_BYTES from SUPPLY_BYTES is the remaining amount (REMAIN_BYTES) in bit distribution. Also, the bit amount obtained by adding HEADER to TARGET_BYTES is TARGET_OUT_BYTES, which is the sum of the bit amounts scheduled to be output by the bit distribution calculation. Equation (3),
This is shown in (4).

[0024]

[Expression 3] REMAIN = SUPPLY_BYTES-TARGET_BYTES (3)

[0025]

TARGET_OUT_BYTES = TARGET_BYTES + HEADER (4) Next, the calculation processing of the bit distribution amount in picture units will be described. The target bit amount for each picture is calculated according to the Difficulty and the bit amount (SUPPLY_BYTES) given to the whole, and a control file for the encoder is created.

At that time, as a calculation process of the target bit amount, it is assumed that the bit amount is firstly distributed in GOP units, and the bit distribution according to the Difficulty of each picture is performed in each GOP. Here is the sum of Difficulty for each GOP
The bit distribution amount (gop_target) in GOP units at the time of encoding is determined according to gop_diff.

FIG. 6 is a diagram showing an evaluation function. The vertical axis shows the bit distribution (TARGET), and the horizontal axis shows Difficulty. The evaluation function is a conversion function between gop_diff and gop_target.
Y = AX + B, where Y is gop_target and X is gop_diff
It is expressed by the following equation. Since B is known as GOP MINBYTES from the figure, A can be obtained. First, USB_BYTES is obtained.
The calculation formula is the formula (1) described above.

Next, SUPPLY_BYTES and Di of all pictures
Find Difficulty_SUM, which is the sum of fficulty. The calculation formulas are formulas (5) and (6).

[0029]

[Equation 5] SUPPLY_BYTES = USB_BYTES−TOTAL_HEADER (5)

[0030]

(6) Difficulty_SUM = ΣDifficulty (6) Since ま た Y = A × ΣX + B × n, ΣY = SUPP
If LY_BYTES, ΣX = Difficulty_SUM, n is the total number of GOPs, A is given by equation (7).

[0031]

[Mathematical formula-see original document] A = (SUPPLY_BYTES-B * n) / Difficulty_SUM (7) Therefore, since the evaluation function is Expression (8),

[0032]

Gop_target = A × gop_diff + B (8) gop_diff and gop_target can be calculated. Also GO
In the case where the distribution to each picture in P is proportional to the magnitude of Difficulty, the target amount for each picture is given by equation (9).

[0033]

[Mathematical formula-see original document] TARGET (k) = gop_target * Difficulty (k) / gop_diff (9) Note that extremely difficult in the material (gop_diff is large)
If there is a picture, the amount of gop_target becomes very large and exceeds the maximum rate allowed by the system. Therefore, it is necessary to apply a limiter with a fixed amount such as GOP MAXBYTES. Also, the minimum target amount is GOP
Limited by MINBYTES.

Next, VBV (Video_Buffering_Verifi)
er) will be described. At the time of MPEG video encoding, it is required to distribute bits while taking into consideration the remaining buffer capacity of the virtual decoder. This calculation of the remaining virtual buffer is called VBV. FIG. 7 is a diagram showing a VBV calculation process.

In the case of DVD, buffer size VBVMA
For X (1.75 Mbits), assuming that the start point of the k-th picture buffer is Occupancy_up (k) and the target amount of the k-th picture is TARGET (k), the buffer after bits are discharged to the picture Occupancy
_Down (k) is represented by equation (10).

[0036]

Occupancy_down (k) = Occupancy_up (k) −TARGET (k) (10) In this buffer, the data amount (SYSTEM_S) of the bit rate according to the video data amount from the decoder pickup is provided.
UPPLY) is accumulated.

[0037]

[Equation 11] SYSTEM_SUPPLY = MAXRATE * KT (11) Then, the remaining buffer amount Occupancy_up (k +
1) is represented by equation (12).

[0038]

(12) Occupancy_up (k + 1) = Occupancy_down (k) + SYSTEM_SUPPLY (12) This supply amount corresponds to the amount that rises to the upper right in the figure. The higher the supplied bit rate, the greater the slope, and the more the data tends to accumulate in the buffer. When the buffer is full, the supply from the pickup to the buffer is stopped, so that it is not necessary to consider the overflow of the buffer. This means that it is not necessary to control exactly at a certain set value, but it is only necessary to control so as to be equal to or more than the set value.

Conversely, if the data amount of each picture is large, the amount of data stored in the buffer decreases. The target bit amount is calculated so that this buffer remaining amount does not become less than a certain value. The first Occupancy_up (0) of this calculation starts from a fixed value (VBVMAX * 2/3 in this example).

[0040]

[Expression 13] Occupancy_up (0) = VBVMAX * 2/3 (13) Next, the VBV buffer calculation processing will be described. FIG.
FIG. 9 is a diagram illustrating an example of distribution of target bits in GOP units. FIG. 8 is a diagram showing a target bit amount obtained in consideration of GOP MAXRATE, and FIG. 9 is a diagram showing a target bit amount obtained by performing VBV restriction processing.

The pictures of picture numbers 1, 4, and 7 in FIG. 8 are below the value of VBVMIN which is the lower limit of the VBV buffer. Therefore, the target bit amount of a GOP including a picture whose VBV is lower than VBVMIN is reduced to a target bit amount as shown in FIG.

Here, the Occupa when the VBV calculation is executed with the target amount before the VBV restriction in the GOP is applied.
Let the minimum value of ncy be Occ_min. Then, the start point kstart at which the restriction is performed is such that Occupancy_up (k) has a reference value (V
(BVLINE: VBVMAX * 3/4) and the value of Occupancy_up (k) at this time is defined as Occ_start. When Occ_min <VBVMIN, the first distribution ratio r is as shown in Expression (14).

[0043]

R = (Occ_start−VBVMIN) / (VBVSTART−Occ_min) (14) The target bit amount given in this way is GOP MAXR
Since the distribution must be performed so as to observe the ATE restriction and the VBV buffer restriction, there may be a case where the target amount must be simply reduced from the target amount obtained by the evaluation function. Therefore, the sum total of the target amounts after the restriction (TARGET_BYTES) becomes smaller than the total target bit amount (SUPPLY_BYTES), and a remainder (REMAIN_BYTES) occurs. Normally, the cycle is such that the surplus amount is redistributed in order to increase the bit distribution ratio.

FIG. 10 is a diagram showing an evaluation function of the remaining bit distribution. Here, an evaluation function of Y = QX + R is used. X is gop_diff, and Y is the amount of change (GOP_TARGET_AD) of the target amount redistributed for each GOP.
D). Dx is Y = AX + B and Y = GOP MAXBYTES
Is the value of the intersection with

Next, a description will be given of GOP_TARGET_ADD and the amount of distribution of retarget bits in the GOP. The minimum value of gop_diff which becomes the maximum number of bytes of GOP by the evaluation function is D
Then, from GOP MAXRATE = A × D + B,

[0046]

D = (GOP MAXRATE−B) / A (15a) R = −Q × D (15b) ΣY = Q × (ΣX−D × n) (15c) where X <D is satisfied. Di total of Difficulty of picture
fficulty_SUM and the number of pictures are picture_number.

ΣY = REMAIN_BYTES, ΣX = Difficulty
_SUM (X <D), n = picture_number (X <D),

[0048]

Q = (REMAIN_BYTES) / (Difficulty_SUM−D × n) (16) Therefore, the surplus target distribution amount for each GOP is

[0049]

GOP_TARGET_ADD = Q × gop_diff + R (17) Further, the distribution amount of the re-target bits of each picture in the GOP is:

[0050]

TARGET_add (k) = GOP_TARGET_add × Difficulty (k) / gop_diff (1 ≦ k ≦ the number of pictures in the GOP) (18) The surplus amount has become a certain amount or less, or If the distribution loop exceeds a certain number of times, the bit redistribution calculation is aborted and the encoded bit stream is RAID
Set the address to write to and output the control file for the encoder. By performing the encoding process using the control file created in this way,
Variable bit encoding according to Difficulty is executed.

Next, it is considered that the buffer distribution calculation device of the present invention performs the bit distribution calculation under a high bit rate condition (AVERAGE_RATE and MAXRATE are close values). here
AVERAGE_RATE is an average bit rate at the time of encoding.

[0052]

[Equation 19] AVERAGE_RATE = USB_BYTES / TOTAL_FRAME_NB / KT (19) FIGS. 11 and 12 are diagrams showing a process of calculating the remaining amount of VBV, and FIG. 11 shows the distribution of target bits before the restriction is applied. FIG. 12 shows a case where the VBV buffer calculation according to the present invention is performed on the target amount obtained in consideration of the evaluation function and the GOP MAXRATE restriction.

In the picture of k = 2, 4, 5, and 6 in FIG. 11, the value is lower than the value of VBVMIN which is the lower limit of the VBV buffer. Therefore, the target amount of a GOP including a picture whose VBV is lower than VBVMIN is reduced. VB in GOP
Before adding V limit, look ahead for each target amount and Occupa
Calculate the value of ncy and search for the location and value where the minimum value of Occupancy is Occ_min.

The remaining amount limit range detecting means 11 sets the start point kstart at which the restriction is made to the value of Occupancy_up (k) at which the value of Occupancy_up (k) is equal to or greater than the reference value, and sets the value of Occupancy_up (k) at this time to Occ_st
art. The distribution ratio calculation means 12 takes the minimum value of r given by equation (22c) at the position where Occ_min is updated from kstart as the distribution ratio r to be restricted. Equation (22b) is the first distribution ratio, and equation (22a) is the second distribution ratio.

Oc when Occupancy_down (k) <VBVMIN
Find the minimum value Occ_min of cupancy_down (k). Occ
If the position at the time of _min> Occupancy_down (k) is kmin,

[0056]

Occ_min = Occupancy_down (k) (20a) SPMIN = ΣSYSTEM_SUPPLY (k) (kstart ≦ k ≦ kmin-1) (20b) TGMIN = ΣTARGET (k) (kstart ≦ k ≦ kmin) (20c) Also, (Occ_start + SPMIN) −TGMIN = Occ_min,
(Occ_start + SPMIN) − TGMIN × rt = VBVMIN,

[0057]

Rt = 1− (VBVMIN−Occ_min) / TGMIN (21a) r ° = (Occ_start−VBVMIN) / (VBVSTART−Occ_min) (21b) r = MIN (r °, rt) (21c) The remaining amount limit range detecting means 11 sets the end point (kend) of the limited range to the Occu corrected by this ratio.
The value of pancy_up (k) is the position where Occ_end is greater than VBVLINE. At this position, the bit amount calculating means 13
Multiplies the distribution ratio, which uniformly limits the targets in the range. By performing such processing, the distribution ratio can be kept constant, so that even after VBV restriction, the bit amount according to Difficulty can be distributed.

The remaining buffer capacity is calculated again based on the target corrected for the calculation of VBV in the next section.

[0059]

(22) Occ_end = Occ_start + SPEND-TGMIN × rt (22a) SPEND = ΣSYSTEM_SUPPLY (k) (kstart ≦ k ≦ kend) (22b) TGMIN = ΣTARGET (k) (kstart ≦ k ≦ kend) (22c) When Occ_end> VBVLINE, k = kend and kstart ≦ j
Execute the following process in the range of ≤kend.

[0060]

TARGET (j) = TARGET (j) · r (23a) Occupancy_down (j) = Occupancy_up (j) −TARGET (j) (23b) Occupancy_up (j + 1) = Occupancy_down ( k) + SYSTEM_SUPPLY ... (23c) r = (Occ_start-VBVMIN) / (VBVSTART-Occ_min) ... (23d) As a result of ending the processing as described above, FIG.
Modified as 2.

Next, the calculation flow of the VBV calculation according to the present invention will be described. FIG. 13 and FIG. 14 are flowcharts showing the processing procedure of the VBV calculation. The details have been described above, and will not be described. [S10] k = 0, MODE = 0, Occupancy_up (k) = VBVSTAR
T [S11] Occupancy_down (k) = Occupancy_up (k)
-TARGET (k), SYSTEM_SUPPLY (k) = MAXRATE * KT [S12] It is determined whether MODE = 0. If the value is 0, the process proceeds to step S13; otherwise, the process proceeds to step S20. [S13] r = 1.0, SPEND = TGEND = 0, Occ_min = VBVMIN [S14] If Occupancy_down (k) <VBVMIN, go to step S20, otherwise go to step S15. [S15] If Occupancy_up (k)> VBVLINE, go to step S16, otherwise go to step S17. [S16] KSTART = k, Occ_min = VBVMIN, Occ_st
art = Occupancy_up (k) [S17] Occupancy_up (k + 1) = Occupancy_down
(k) + SYSTEM_SUPPLY (k) [S18] k = k + 1 [S19] If k> KSTOP, the process ends; otherwise, the process returns to step S11. [S20] MODE = 1 [S21] If Occ_min> Occupancy_down (k), the flow proceeds to step S22; otherwise, the flow proceeds to step S23. [S22] Occ_min = Occupancy_down (k), TGMIN =
ΣTARGET (j) KSTART <j <k, rt = 1- (VBVMIN-Occ_min)
/ TGMIN, r = MIN (r °, rt) [S23] TGEND = TGEND + TARGET (k), SPEND = SPEND + SYST
EM_SUPPLY (k), Occ_END = Occ_start -r TGEN
D + SPEND [S24] If Occ_end> VBVLINE or k = KSTOP, go to step S25, otherwise go to step S17.
Return to [S25] k = KEND, j = KSTART [S26] TARGET (j) = TARGET (j) · r, Occupancy_do
wn (j) = Occupancy_up (j) -TARGET (j), Occupancy
_Up (j + 1) = Occupancy_down (j) + SYSTEM_SUPPLY (j) [S27] j = j + 1 [S28] If j> KEND, return to step S29, otherwise return to step S26. [S29] MODE = 0 and the process returns to step S18.

As described above, the buffer remaining amount limit processing device of the present invention calculates the distribution ratio of the bit amount so as to be equal to the distribution ratio before the buffer remaining amount is limited, and distributes to the picture from the distribution ratio. The amount of bits to be obtained is obtained and the remaining buffer amount is limited. As a result, the bit amount according to the Difficulty of the image can be distributed even after the buffer remaining amount is limited, so that it is possible to improve image quality deterioration.

[0063]

As described above, the buffer remaining amount limit processing device of the present invention calculates the distribution ratio of the bit amount to be equal to the distribution ratio before the buffer remaining amount is restricted, and from this distribution ratio, In this configuration, the buffer amount is limited by calculating the amount of bits to be distributed to the buffer. As a result, the bit amount according to the difficulty of the image can be distributed even after the buffer remaining amount is limited, so that the deterioration of the image quality can be improved.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a buffer remaining amount limit processing device of the present invention.

FIG. 2 is an overall view of an MPEG video encoding system.

FIG. 3 is a diagram showing a GOP structure.

FIG. 4 is a flowchart showing an encoding operation process.

FIG. 5 is a diagram showing a process in a bit distribution calculation.

FIG. 6 is a diagram showing an evaluation function.

FIG. 7 is a diagram showing a VBV calculation process.

FIG. 8 is a diagram showing an example of target bit distribution in GOP units.

FIG. 9 is a diagram illustrating an example of target bit distribution in GOP units.

FIG. 10 is a diagram showing an evaluation function of distribution of remaining bits.

FIG. 11 is a diagram showing a process of calculating a VBV remaining amount.

FIG. 12 is a diagram showing a process of calculating a VBV remaining amount.

FIG. 13 is a flowchart illustrating a processing procedure of VBV calculation.

FIG. 14 is a flowchart illustrating a processing procedure of VBV calculation.

[Description of Signs] 11 ... Remaining amount limit range detecting means, 12 ... Distribution ratio calculating means, 13 ... Bit amount calculating means.

Claims (5)

[Claims] 1. A buffer remaining amount processing device for limiting the remaining amount of a buffer so that the amount of bits stored in the buffer is not reduced below a predetermined value when distributing the amount of bits stored in the buffer to a picture at the time of encoding a video signal. A remaining amount limit range detecting means for detecting a remaining amount limit range in which the amount is limited; and a distribution ratio of a bit amount to each picture within the remaining amount limit range becomes equal to that before the buffer remaining amount limit is performed. A buffer ratio calculating means for calculating the distribution ratio, and a bit amount calculating means for calculating the bit amount to be distributed to the picture based on the distribution ratio. 2. The remaining capacity limit range detecting means sets a picture having a buffer occupancy value exceeding a preset buffer remaining capacity reference value as a start position of the remaining capacity limit range. Buffer remaining amount processing device according to the above. 3. The remaining capacity limit range detecting means ends the remaining capacity limit range for a picture whose buffer occupancy value corrected by the distribution ratio exceeds a preset buffer remaining capacity reference value. 2. The buffer remaining amount limit processing device according to claim 1, wherein the position is a position. 4. The distribution ratio calculation means includes: a first distribution ratio that does not consider a sum of bit amounts to be distributed to each picture within the remaining amount limit range; And a second distribution ratio taking into account the sum of the bit amounts to be distributed to each other is calculated, and the smaller one of the first distribution ratio and the second distribution ratio is calculated as the distribution ratio. 2. The buffer remaining amount processing device according to claim 1, wherein: 5. The bit amount calculation unit according to claim 1, wherein the bit amount is calculated by multiplying the distribution ratio by a bit amount before the buffer remaining amount is limited.
Buffer remaining amount processing device according to the above.