JPH11252554A - Coding and multiplexing system and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a coding and multiplexing system and its method by which transmission efficiency is considerably enhanced. SOLUTION: In this coding and multiplexing system, a multiplexer assigns an excess frequency band with respect to a setting rate of rate conversion means 21A-21N and coding means 22A-22N for a frequency band used for reading 1st or 2nd coded data from 1st buffer 25 or a 2nd buffer 33. In this coding and multiplexing method, an excess frequency band with respect to each channel consisting of rate-converted coding data or real-time-coded data is assigned for a frequency band for reading other channels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order.

BACKGROUND OF THE INVENTION Problems to be Solved by the Invention (FIG. 7) Means for Solving the Problems Embodiments of the Invention (1) Principle (FIGS. 1 and 2) (2) This embodiment Configuration of Transmission System According to Embodiment (FIGS.
(FIG. 6) (3) Operation and effects of this embodiment (FIGS. 1 to 6) (4) Other embodiments (FIGS. 1 to 6) Effects of the invention

[0003]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coding and multiplexing apparatus and a coding and multiplexing method, and is suitable for application to, for example, digital multi-channel broadcasting.

[0004]

2. Description of the Related Art In recent years, communication satellites (C
S: Communication Satellite) has started digital multi-channel broadcasting. In the near future, similar services are scheduled for a broadcasting system using a broadcasting satellite (BS) or a terrestrial or cable television.

[0005]

When digital multi-channel broadcasting is performed, for example, a local station or a cable television broadcasting station broadcasts a program distributed from another station in some channels and broadcasts the remaining programs in some channels. It is conceivable to broadcast your own program on the channel.

Accordingly, in a local station or a cable television broadcasting station, a transmission system capable of multiplexing program data distributed from another station and program data unique to the own station within a limited band and broadcasting the data is provided. Required.

FIG. 7 shows an example of the configuration of such a transmission system. A plurality of rate converters 2A to 2N and a plurality of encoders 3A to 3N are provided at the input stage. The coded data D1 of the program distributed from, for example, another station or the like is provided to each of the conversion devices 2A to 2N, and the video signals S1A to S1N of the program unique to the broadcasting station are provided to each of the coding devices 3A to 3N.

In each of the rate converters 2A to 2N,
The rate is set to a predetermined value for the channel by a method of decoding the supplied coded data D1A to D1N and then re-encoding the data, or a method of reducing higher-order coefficients without decoding. (Hereinafter, referred to as a set rate), and the resulting encoded data D2
A to D2N are sent to the multiplexer 4.

In each of the encoding devices 3A to 3N,
The supplied video signals S1A to S1N are compression-encoded at the set rate of the channel, and the obtained encoded data D3A to D3N are sent to the multiplexer 4. Note that the set rate of each channel is set in advance so that the total is within the band allowed for the broadcast station.

In the multiplexing device 4, a plurality of buffers 5A to 5N, 6A to 6N provided in correspondence with the rate conversion devices 2A to 2N and the encoding devices 3A to 3N, respectively.
6N, and a multiplexing control unit 7 for controlling the reading and writing of the buffers 5A to 5N and 6A to 6N.

In this case, the multiplexing control unit 7 includes coded data D2A to D2N and D3A to D3 supplied from the rate conversion devices 2A to 2N and the coding devices 3A to 3N, respectively.
3N is sequentially taken into the corresponding buffers 5A to 5N and 6A to 6N, and is sequentially read from the buffers 5A to 5N and 6A to 6N in a time-division manner at the set rate of the channel.

As a result, each of these buffers 5A to 5N, 6
Encoded data D2A to D2 read from A to 6N
N, D3A to D3N are provided to the transmission unit 9 as transmission data D4 via the data bus 8, and after being subjected to predetermined signal processing in the transmission unit 9, are transmitted to the reception side as a transmission signal S2.

As described above, in the transmission system 1, the encoded data D1A to D1N provided from other stations are provided.
And multiplexed data D3A to D3N obtained by encoding the video signals S1A to S1N unique to the own station so that digital multi-channel broadcasting can be performed.

However, in the transmission system 1 having such a configuration, since the rates are fixedly assigned to the respective channels, the encoding devices 3A to 3N have a complicated structure when compressing and encoding the video signals S1A to S1N. There is a problem that image quality degradation in a picture or scene change becomes very large.

In the transmission system 1, since the rates are fixedly assigned to the respective channels, the video signals S1A to S1 in the encoding devices 3A to 3N.
Even for a pattern that does not require much code when compressing and encoding 1N, it is necessary to add dummy data in order to keep the output rate constant, and there is a problem that transmission efficiency deteriorates.

The present invention has been made in view of the above points, and an object of the present invention is to propose a coding multiplexing apparatus and a coding multiplexing method capable of significantly improving transmission efficiency.

[0017]

According to the present invention, there is provided an encoding / multiplexing apparatus for storing rate-converted first encoded data output from corresponding rate converting means. A first buffer, a second buffer for storing second encoded data obtained by compression-encoding the video signal output from the corresponding encoding means, and a second buffer for storing the first and second buffers. The first and second encoded data are read out at a specific set rate preset for the corresponding rate conversion means or encoding means, respectively, to multiplex the first and second encoded data. Multiplexing means, and the multiplexing means corresponds to a surplus band for the set rate of the rate conversion means and the encoding means with another rate conversion means and / or encoding means. That was to distribute the first or reading of the second encoded data from the first and or second buffer.

As a result, in this coding and multiplexing apparatus, the band control for each channel can be dynamically performed, and the temporal change of the code amount at the time of rate conversion and coding is absorbed between the channels. can do.

According to the present invention, in the coding and multiplexing method, each of the input coded data for one or a plurality of channels is converted into a different rate and stored in a different first buffer. A first step of compressing and encoding the video signals of the respective minutes and storing them in different second buffers, respectively, and a first and a second coded data stored in the first and second buffers, respectively. A second step of performing multiplexing by reading in a time-division manner at a specific set rate preset for each channel is provided. In the second step, a surplus band for the read rate of each channel is set to another band. The first and / or second coded data is read from the first and / or second buffer corresponding to the channel.

As a result, according to this encoding and multiplexing method,
Band control can be dynamically performed for each channel, and a temporal change in the code amount at the time of rate conversion or encoding can be absorbed between the channels.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

(1) Principle As shown in FIG. 1, a video signal S10 for a plurality of channels is provided.
A to S10N are respectively different from encoding devices 11A to 11
N to obtain the respective encoded data D1.
For a multiplexing system 10 that multiplexes the signals 0A to D10N within a predetermined transmission band by the multiplexing device 12, virtual buffers 13A to 13A to coded devices 11A to 11N and the multiplexing device 12, respectively. Consider the case where 13N is provided.

In this case, the coded data D10A to D10 from each of the coding devices 11A to 11N to the buffers 13A to 13N.
In writing 10N, one picture unit is set as an access unit, and the access unit is instantaneously written. The writing cycle is set to each of the encoding devices 11A to 11A.
It is assumed that the picture period is the picture cycle of the video signals S10A to S10N input to the 1N. Also, each of the encoding devices 11A to 11A
In N, it is assumed that a unique coding rate is set in advance so that the total does not exceed the broadcasting band of the digital multi-channel broadcasting.

If the encoding devices 11A to 11N are the writing times of arbitrary pictures n to the buffers 13A to 13N based on the video signals S10A to S10N,
Buffers 13A-13 just before writing the picture n
The data occupancy of N is C ₀ [bit], the code amount of picture n is C [n] [bit], and picture n is a buffer 13A to 13A.
Tw [n] [s] is the time from writing to N to reading of the head (hereinafter referred to as a waiting time), and the set rate of the encoding devices 11A to 11N is R ₀ [bps
], And if the picture period is Tf [s], the waiting time Tw [n + 1] of the following picture n + 1 is given by the following equation.

(Equation 1) Given by

The waiting time Tw [n + 1] is given by the following equation:

(Equation 2) If

(Equation 3) Encoded data D10A to D1 for the code amount A given by
0N to can be extra transmitted within a set rate R ₀ for the encoding device 11A to 11N.

Therefore, in this case, during the period from the writing time of the picture n to the writing time of the next picture n + 1 (corresponding to a picture cycle), the encoding devices 11A to 11A to 11D are used.
The read rate of the coded data D10A to D10N from the buffers 13A to 13N corresponding to 11N is represented by the following equation.

(Equation 4) By setting as follows, the encoding device 11A
Of the set rates R ₀ assigned to 11N

(Equation 5) Is defined as a surplus band (hereinafter, referred to as a gap band), and this is referred to as other coding devices 11A to 11N.
Can be sorted.

In this case, however, the coded data D10 is transmitted from the buffers 13A to 13N corresponding to the other coding devices 11A to 11N by such a gap band sorting operation.
When A to D10N are read continuously at a high rate,
Overflow may occur in the buffer on the receiving side. Therefore, in order to avoid such an overflow, it is necessary to provide a limit on the amount of codes to be allocated to the gap bands of the other encoding devices 11A to 11N (hereinafter, this will be referred to as a congestion limit).

In this case, a buffer 13A for a certain picture n
-13N, the picture n and a plurality of consecutive pictures n-5 to n-
FIG. 2 shows the relationship between the waiting time Tw [i] (i = n-5 to n) and the transmission time from the writing of one coded data D10A to D10N to the corresponding buffers 13A to 13N until the decoding. It is assumed that the state shown in FIG.

In this state, the maximum value of the code amount that can be allocated to another gap band by the writing time of the next picture n + 1 is, as shown in FIG. 2B, the picture n that has not reached the decoding time. All the waiting times from −5 to n can be estimated retroactively and obtained as a value whose minimum value is zero.

Actually, the maximum value Z _max [bit] of the code amount
Is the oldest picture number that has not reached the decryption time
The waiting time Tw [n] of the picture n is expressed by the following equation as Nb.

(Equation 6) And the waiting time Tw [i] of each picture i (i = Nb to n-1) up to the picture number Nb that has not reached the previous decoding time is given by

(Equation 7) By the following equation,

(Equation 8) Can be obtained as

On the other hand, in order to avoid underflow of the buffer on the receiving side, each of the encoding devices 11A to 11A
It is necessary to limit the code amount per picture for N.

In practice, assuming that some of the encoding devices 11A to 11N are at the writing time of the picture n, the maximum value C _max [bi of the code amount of the picture Nf several frames after the picture n is assumed.
t] is the encoded data D10A to D10N of the picture n
C ₀ The data occupancy quantity of code buffer immediately before writing
[Bit], the code amount of the picture n is C [n] [bit], the waiting time of the picture n is Tw [n] [s], and its encoding device 11
R ₀ [bit] setting rate for A～11N, Tf [s] a picture period, the offset period as T ₀ [s], the following equation to picture n + 1 of the waiting time Tw [n + 1]

(Equation 9) The waiting time Tw [i] of the subsequent picture i (i ≧ n + 2) is calculated by the following equation.

(Equation 10) By the following equation,

[Equation 11] Can be obtained as

(2) Configuration of Transmission System According to the Present Embodiment FIG. 3 in which the same reference numerals are assigned to parts corresponding to FIG. 7 shows a transmission system 20 according to the present embodiment.
A plurality of rate converters 21A to 21N and a plurality of encoders 22A to 22N are provided.
Coded data D1A to D1N are provided to A to 21N, respectively, and video signals S1A to S1N are provided to each of the coding devices 22A to 22N.

In each of the rate converters 21A to 21N, a code amount converter 23, a rate conversion controller 24
And the buffer 25, and supplies the supplied encoded data D1A to D1N to the code amount conversion unit 23.

At this time, the rate conversion control unit 24 determines the data occupation amount C ₀ of the buffer 25 at that time, the code amount per picture up to the picture n to be restricted, and the set rate R ₀ previously allocated to the channel. The code amount limit value calculation program shown in FIG. 4 is executed on the basis of
_{The maximum} is calculated, and this is given to the code amount conversion unit 23 as the control signal S10.

The code amount converter 23 converts the supplied coded data D1A to D1N into a code amount that does not exceed the limit value _Cmax obtained based on the control signal S10, and obtains the obtained coded data D20. To the rate conversion control unit 2
Under the control of (4), one picture is stored collectively in the buffer 25 at a picture cycle.

At this time, the rate conversion control unit 24 outputs a reference time (ST) of a 24-hour cycle supplied from the reference time management unit 27 of the multiplexer 26 via the first control bus 28.
C: System Time Clock) Based on the information D21, the time at which the encoded data D20 of the picture n is written to the buffer 25 is tp [n], the buffer size on the receiving side is B, and the set rate assigned to the channel is R _0. As
Next formula

(Equation 12) To calculate the time at which the picture n is to be decoded, and decode time information DTS (Decodi
ng Time Clock) [n] is replaced with the DTS previously added to the encoded data D20 of the picture n,
The time reference value (PCR: Program Clock Reference) added to the encoded data D20 is replaced with a time obtained based on the reference time information D21 at that time,
These are stored in the buffer 25 together with the coded data D20.

Further, at this time, the rate conversion control unit 24
A data occupancy quantity C ₀ of buffer 25 just before writing the coded data D20 of the picture n, a code amount C [n] of the picture n, on the basis of such a set rate R ₀ assigned to that channel Figure By executing the surplus transmission code amount calculation program shown in FIG. 5, a code amount A that can be transmitted extra in the range of the set rate _R0 is obtained, and this is set as surplus transmission code amount information D22A to D22N on the second control bus. The signal is sent to the multiplexing control unit 30 of the multiplexing device 26 via the multiplexing device 29.

Further, the rate conversion control unit 24 further includes a buffer data occupation amount CC ₀ immediately before writing the picture n and a code amount C of the picture n necessary for obtaining the maximum value Z _max of the congestion limit. [n] and the channel setting rate R ₀ (hereinafter referred to as congestion limit value calculation information) D23A to D23N are multiplexed by the multiplexing device 26 via the second control bus 29. Control unit 3
Send to 0.

On the other hand, each of the encoding devices 22A to 22N includes an encoding unit 31, an encoding control unit 32, and a buffer 33, and supplies the supplied video signals S1A to S1N to the encoding unit 31. I do.

The encoding control unit 32 at this time, in the same manner as rate conversion control unit 24 of the rate conversion device 21A through 21N, picture of the data occupancy quantity C ₀ of buffer 33 at that time, to picture n of restricted By executing the code amount limit value calculation program shown in FIG. 4 based on the unit code amount and the set rate R ₀ allocated to the channel, the code amount limit value C per picture at that time is obtained.
_max is calculated, and the calculated value is used as a control signal S11.
Give to 1.

Thus, the encoding section 31 compresses and encodes the supplied video signals S1A to S1N to a code amount not exceeding the limit value _Cmax obtained based on the control signal S11, and encodes the obtained coded data D24. Under the control of the control unit 32, one picture is stored in the buffer 33 at a cycle of the picture and collectively.

At this time, the encoding control unit 32 sends the first control bus 28 from the reference time management unit 27 of the multiplexer 26.
Based on the reference time information D21 given through
By calculating the equation (12), a time at which the picture n is to be decoded is calculated, and decoding time information DT indicating the time is calculated.
S [n] is replaced with the DTS previously added to the encoded data D24 of the picture n, and the time reference value added to the encoded data D24 is obtained based on the reference time information at that time. And stores them in the buffer 33 together with the coded data D24.

Further, at this time, the coding control unit 32 stores the data occupation amount C ₀ of the buffer 33 immediately before writing the coded data D24 of the picture n, the code amount C [n] of the picture n, and the channel. By executing the surplus transmission code amount calculation program shown in FIG. 5 based on the assigned set rate R ₀ and the like, the set rate R ₀
Is obtained as a surplus transmission code amount information D25A to D25N.
To the multiplexing control unit 30 of the multiplexing device 26 via the control bus 29 of FIG.

[0045] Further coding control unit 32, multiplexing the convergence limit value calculation information D26A~D26N including various information necessary for obtaining the maximum value Z _max of the congestion restriction therewith via a second control bus 29 Control section 3 of the multiplexing device 26
Send to 0.

In the multiplexing control unit 30, surplus transmission code amount information D22A to D22N provided from the rate conversion control unit 24 of each of the rate conversion devices 21A to 21N and the coding control unit 32 of each of the coding devices 22A to 22N. ,
Based on D25A to D25N, how much gap band is generated in which channel is recognized, and for each channel where no gap band is generated, the rate conversion control unit 24 of the corresponding rate conversion device 21A to 21N. Alternatively, the congestion limit value calculation information D23A to D23A provided from the coding control unit 32 of each of the coding devices 22A to 22N.
D23N, slave connexion calculates the maximum value Z _max of the amount of codes to be distributed to the gaps band of another channel congestion limit value calculation program shown in FIG. 6 based on D26A～D26N.

Based on the result of the calculation, the multiplexing control unit 30 assigns the code amounts A _{1 to} A to each of the channels from which no gap band is generated to the other channels.
_m and the code amounts Z _{1 to} Z _m to be distributed from the other channels to each channel in which the gap band has occurred are given by the following equations.

(Equation 13) Is satisfied, and until the writing time of the subsequent picture n + 1 to the buffer, based on the determination result,
For a channel in which no gap band occurs, the set rate of the channel is R ₀ , and the picture period is Tf.

[Equation 14] For a channel having a rate of and a gap band, the set rate of the channel is R ₀ , the picture period is Tf, and the following equation is used.

(Equation 15) The encoded data D20 and D24 are read out from the buffer 25 of each of the rate converters 21A to 21N and the buffer 33 of each of the encoders 22A to 22N in a time-division manner.

The coded data D20 and D24 read out in a time-division manner are thereafter transmitted to the transmission unit 9 via the data bus 39, and after being subjected to predetermined signal processing in the transmission unit 9, , And transmitted to the receiving side as a transmission signal S2.

As described above, in this transmission system 20, the coded data D1A to D1N for a plurality of channels supplied from other stations and the like, and the video signals S1A to S1 unique to the own station.
The coded data D3A to D3N for a plurality of channels obtained by encoding 1N in real time can be multiplexed and broadcast.

(3) Operation and effect of the present embodiment In the above configuration, in the transmission system 20, in each of the rate converters 21A to 21N, the rate of the coded data D1A to D1N to be input is set to the corresponding channel. The video signals S1A to S1N to be input are compression-encoded in the respective encoding devices 22A to 22N, while the video signals S1A to S1N are compressed and encoded in the respective encoding devices 22A to 22N. A gap band for the set rate of the channel is calculated, and based on the calculation result, the encoded data D from the buffers 25 and 33 of the channel in which the gap band has occurred.
The readout rate of D20 and D24 (corresponding to the set rate of the channel) is reduced, and the readout rate is allocated to the readout of the encoded data D20 and D24 from the buffers 25 and 33 of the other channels where no gap band is generated.

Therefore, in the transmission system 20, even when a gap band occurs in any one of the channels, the gap band can be effectively used without adding dummy data.

In the transmission system 20, each rate conversion device 21A-21N and each coding device 22A-22
Since N only keeps the code amount limit per picture, it is possible to decode each picture at the designated decoding time without causing overflow and underflow in the buffer on the receiving side. Control can be performed reliably.

According to the above configuration, the multiplexing device 26 dynamically detects a band which is not required for the channel among the set rates preset for each channel, and distributes the band to a channel having no margin. By doing so, it is possible to dynamically control the band of each channel,
Thus, a transmission system that can significantly improve transmission efficiency can be realized.

(4) Other Embodiments In the above embodiment, the multiplexing control unit 30 of the multiplexer 26 is assigned to each channel from the writing time of the picture n to the writing time of the picture n + 1. The surplus band of the band is allocated to another channel so that the corresponding buffer 2 of each channel is allocated.
The case where the readout rate from each of the buffers 5 and 33 is varied has been described. However, the present invention is not limited to this. For example, the multiplexing control unit 30 constantly monitors the data occupancy of each of the buffers 25 and 33, and When the buffers 25 and 33 are empty, the band allocated to the channel may be allocated to another channel.

In the above-described embodiment, the rate conversion devices 21A to 21A as rate conversion means for converting the rates of the input encoded data D1A to D1N, respectively.
A plurality of 1N (code amount conversion units 23) are provided, and a plurality of (encoding units 31) of encoding devices 22A to 22N as encoding means for compressing and encoding the input video signals S1A to S1N are provided. However, the present invention is not limited to this, and one or both of them may be provided one by one.

[0056]

As described above, according to the present invention, in a coding and multiplexing apparatus, a first buffer for storing rate-converted first coded data output from corresponding rate converting means is provided. A second buffer for storing second encoded data obtained by compression-encoding the video signal output from the corresponding encoding means, and a first or second buffer stored in each of the first and second buffers. And multiplexing means for multiplexing each of the first and second coded data by reading out the second coded data at a specific set rate preset for the corresponding rate conversion means or coding means. A multiplexing means for converting a surplus band for the set rate of the rate conversion means and the coding means into first and / or second buffers corresponding to the other rate conversion means and / or the coding means. To read the first or second coded data from the multiplexing unit, so that the band control for each channel can be dynamically performed, and thus the coding and multiplexing that can significantly improve the transmission efficiency can be performed. The device can be realized.

According to the present invention, in the coding and multiplexing method, each of the input coded data for one or more channels is converted into a different rate and stored in a different first buffer. A first step of compressing and encoding the video signals of the channels and storing them in different second buffers, respectively, and a first and a second encoded data stored in the first and second buffers, respectively. There is provided a second step of performing multiplexing by reading in a time-division manner at a specific set rate preset for each channel, and in the second step, a surplus bandwidth for the set rate of each channel is set to another. From the first and / or second buffer corresponding to the first channel
And / or by distributing to reading of the second encoded data, it is possible to dynamically perform band control for each channel, and thus realize an encoding / multiplexing method capable of significantly improving transmission efficiency. it can. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an encoding and multiplexing system used for explaining the principle of the present invention.

FIG. 2 is a schematic diagram for explaining congestion control;

FIG. 3 is a block diagram showing a configuration of a transmission system according to the present embodiment.

FIG. 4 is a schematic diagram illustrating a code amount limit value calculation program.

FIG. 5 is a schematic diagram illustrating a surplus transmission code amount calculation program.

FIG. 6 is a schematic diagram illustrating a congestion limit value calculation program.

FIG. 7 is a block diagram illustrating a configuration example of a transmission system.

[Explanation of symbols]

20 transmission system, 21A to 21N rate conversion device, 22A to 22N coding device, 23 code amount conversion unit, 24 rate conversion control unit, 25, 33 buffer, 26 Multiplexer 27, Reference time management unit 30, Multiplex control unit 31, Encoding unit 32
... Encoding control unit, D1A to D1N, D20, D24 ...
Coded data, D22A to D22N, D25A to D25
N: surplus transmission code amount information, D23A to D23N, D2
6A to D26N: Information for calculating congestion limit value, S1A to S
1N: Video signal.

Claims (6)

[Claims] 1. One or a plurality of rate conversion means for converting a rate of input first encoded data, and a plurality of rate conversion means respectively provided corresponding to each of said rate conversion means,
A first storing unit that stores the rate-converted first encoded data output from the corresponding rate converting unit;
Buffer, one or a plurality of encoding means for compression-encoding each input video signal, and the video signal output from the corresponding encoding means provided in correspondence with each of the encoding means. A second buffer for storing second encoded data obtained by compressing and encoding the first and second encoded data stored in each of the first and second buffers. Multiplexing means for multiplexing each of the first and second encoded data by reading out at a specific set rate preset for the rate converting means or the encoding means,
The multiplexing means converts the surplus bandwidth of the rate conversion means and the coding means with respect to the set rate into the first and / or second buffers corresponding to the other rate conversion means and / or the coding means. The first or second from
An encoding and multiplexing device, which sorts out the readout of encoded data. 2. The multiplexing means according to claim 1, wherein said multiplexing means limits respective bands to be allocated to said rate conversion means and / or said encoding means so that a buffer on the decoding side does not overflow. Encoding multiplexing device. 3. The rate conversion means and the coding means respectively rate-convert the first coded data by limiting the amount of code per picture so that the buffer on the decoding side does not underflow. 2. The coding and multiplexing apparatus according to claim 1, wherein said video signal is compression-coded. 4. The input coded data for one or a plurality of channels are stored in different first buffers after converting the rates, and the video signals for one or a plurality of channels are respectively compressed and coded. The first step stored in a different second buffer and the first and second encoded data stored in each of the first and second buffers are preset for each of the channels. A second step of performing multiplexing by reading in a time-division manner at a specific set rate. In the second step, a surplus bandwidth of each of the channels with respect to the set rate corresponds to the other channels. Encoding multiplexing for distributing reading of the first and / or second encoded data from the first and / or second buffer; Method. 5. The encoding and multiplexing method according to claim 4, wherein in the second step, a band is allocated to each of the other channels so that the buffer on the decoding side does not overflow. . 6. In the first step, the rate of the first coded data is converted or the video signal is converted by limiting the amount of code per picture so that the buffer on the decoding side does not underflow. The encoding / multiplexing method according to claim 4, wherein compression encoding is performed.