JP2001136139A - Multiplexer and multiplexing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably operate a broadcast system even on the occurrence of a change in a state of a group. SOLUTION: Encoders 120-1, 120-2,..., 120-N encode a received digital video signal at a bit rate instructed from a controller 110. Thus, the digital video signal is compressed, and a multiplexer 130 multiplexes the compressed video signals. In this encoding processing, statistic data are also generated are transmitted to the controller 110 directly or via the multiplexer 130. The controller 110 dynamically assigns the signal to the encoders 120-1, 120-2,..., 120-N of groups for statistic multiplex in a way that the bit tare is not in excess of the transmission bit rate given to the groups for statistic multiplex on the basis of the statistic data. When there is any setting change in the groups, the controller 110 controls the bit rate assignment so that the bit rate is stably assigned without causing any hindrance to the broadcast system even on the occurrence a change in the setting of the groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexing apparatus and a multiplexing method, and more particularly to a multiplexing apparatus and a multiplexing method for encoding a digital broadcast program, multiplexing the program, and transmitting the multiplexed program.

[0002]

2. Description of the Related Art In recent years, the world of broadcasting has been digitized from satellite broadcasting to terrestrial broadcasting, and the practical use of digital broadcasting has become active. In such a digital broadcast, it is possible to multiplex a broadcast program and transmit many programs to the same transmission path. FIG. 3 is a configuration diagram of the digital satellite broadcasting system. The video / audio signal is input to each of the encoders 211, 212, 213, and 214, and is coded, respectively.
Is output to The multiplexing units 221 and 222 include an EPG
(Electric Program Guide; electronic program guide) The EPG generated by the generating devices 231 and 232 is also input. The coded signals input to the multiplexing units 221 and 222 are subjected to multiplexing processing, and
After frequency modulation is performed at 242, the transmission antenna 250
Is uplinked to satellite 300. Satellite 300
The uplink signal is amplified and downlinked to the receiving station. The receiving station receives the signal at the receiving antenna 410 and performs signal processing at the receiver 420. In the receiver 420, the tuner 421 selects and receives a channel, and the demodulator 422 demodulates the signal. The demodulated signal is separated into an EPG and program information by a separation unit 423, and the program information is decoded by a decoder 424 to return to a video / audio signal.

As described above, "statistical multiplexing" is well known as a technique for more efficiently transmitting a plurality of programs multiplexed and transmitted. Statistical multiplexing can dynamically change the transmission rate of each program. For example, if the deterioration of image quality is not conspicuous even if the transmission rate is reduced, the transmission rate can be reduced to give more transmission rates to other programs, so that multiple programs can be transmitted more efficiently. it can.
In addition, under predetermined restrictions, the bit rate is allocated so that the image quality is improved most as a whole multiple programs,
Improvements in image quality can also be expected. Regarding how much bit rate is assigned as a transmission rate to each program, processing with priority on image quality and processing with priority on average bit rate are well known. In such statistical multiplexing, a plurality of programs for performing statistical multiplexing are defined as a group, and the bit rate of each program is dynamically changed within a range of a transmission rate given to the entire group.

[0004]

However, in the actual operation of statistical multiplexing, there is a problem that if the state of a group changes, the operation of the broadcasting system may be hindered.

In statistical multiplexing, the bit rate of a program belonging to a group is adjusted within the range of the transmission rate given to the entire group.
If the number of programs in the group changes due to deletion or the grouping changes due to encoder failure, etc.,
The system may be disrupted before and after the change.

For example, when the number of programs in a group is changed due to a change in grouping, addition or deletion of a program, or restart of a pause service, if the transmission rate given to the entire group is constant before and after the change, , The bit rate given to each program changes relatively. Before and after this change, depending on the settings of the system, it may be difficult to set the bit rate, and for example, there may be a problem in operation such as exceeding a predetermined transmission rate.

There is no change in the number of programs in a group, such as a change in grouping in which the number of programs in the group does not change, or replacement of equipment due to an encoder failure.
The state may change. In such a case, similarly, depending on the system setting, it is difficult to set the bit rate before and after the change, and there is a possibility that an operational problem may occur. For example, there is a case where the distribution of bit rates may change significantly, such as when changing from a simple video program to a complex video program.

[0008] The present invention has been made in view of such a point, and a multiplexing apparatus and a multiplexing apparatus capable of stably operating a broadcast system even when a state of a group changes. The aim is to provide a method.

[0009]

According to the present invention, in order to solve the above-mentioned problems, in a multiplexing device for encoding a digital broadcast program, multiplexing and transmitting the digital broadcast program, the digital broadcast program to be input is processed by a predetermined algorithm. Encoding means for performing encoding processing in accordance with and generating an encoded signal and statistical data according to the data amount generated at the time of the encoding processing; and a group for performing a predetermined statistical multiplexing processing based on the statistical data. A control means for allocating the bit rate of the encoding means set to, and allocating the bit rate so that the bit rate stably shifts before and after the setting change of the group when the setting of the group is changed, Multiplexing means for multiplexing and outputting the coded signal generated by the coding means set in the group Multiplexing apparatus characterized by having, is provided.

In the multiplexing apparatus having such a configuration, normally, the encoding means corresponding to the digital broadcasting program set in the group performs program encoding processing in accordance with the set bit rate, and performs code encoding. A coded signal is generated, and statistical data corresponding to the amount of data generated during the encoding process is generated. The control means obtains the statistical data, performs a statistical multiplexing process of a predetermined algorithm for each group based on the statistical data, and distributes the bit rate of each encoding means. The allocated bit rate is sent to each encoding unit and set. The multiplexing unit multiplexes and outputs the coded signals of the coding units set in the group. When the setting of the group is changed, the bit rate is adjusted so that the bit rate shifts stably before and after the change, and is transmitted to the encoding means.

In a multiplexing method for encoding a digital broadcast program, multiplexing and transmitting the digital broadcast program, the digital broadcast program is encoded under predetermined conditions to generate statistical data corresponding to the amount of data generated. Setting a bit rate for each program set in a group that performs a predetermined statistical multiplexing process based on the statistical data;
The digital broadcast program is encoded in accordance with the set bit rate, and the procedure of generating the statistical data and performing the predetermined statistical multiplexing process is repeatedly executed. When the setting of the group is changed, the bit rate distribution is performed. A step of allocating the bit rate so that the transition is stable before and after the setting change of the group, multiplexing and outputting the coded signals of the group that have been coded according to the set bit rate, and A multiplexing method characterized by having the following.

Such a multiplexing method encodes the digital broadcasting program according to a set bit rate, generates statistical data according to the amount of data generated by performing the encoding process, and generates a new bit rate. Is repeated. When the setting of the group is changed, the bit rate is adjusted and set so that the bit rate stably shifts before and after the change.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a multiplexing device according to an embodiment of the present invention. The multiplexing device is incorporated in a broadcasting system that multiplexes and transmits broadcast signals, such as the satellite digital broadcasting system described above.

The multiplexing apparatus according to the present invention comprises a controller 110 as control means for setting the bit rate of each program, and encoders 120-1, 120-2,..., 120 as encoding means for encoding the programs. −N (N
Is an arbitrary integer), a spare encoder 121, and a digital signal multiplexer (hereinafter, referred to as a multiplexing unit) that multiplexes the encoded data generated by the encoders 120-1, 120-2,..., 120-N. , A multiplexer) 130
And

The controller 110 controls each encoder 12
, 120-N and the statistical data obtained from the multiplexer 130, the transmission bit rate set for the multiplexer is allocated.
Each of the programs and the encoders 120-1, 120-2,..., 120-N corresponding to each program and the spare encoder 121 are grouped, and the distribution process of the controller 110 is performed in accordance with a predetermined algorithm. Performed in units. For example, in the process of giving priority to the image quality, the bit rates are allocated so that the image quality of the plurality of programs constituting the group is improved as a whole. That is, if the deterioration of the image quality is not conspicuous even if the bit rate is reduced, the bit rate is set low and the bit rate of the video with high complexity is set high. Furthermore, the distribution is adjusted so that the sum of the bit rates of the programs allocated in this manner does not exceed the predetermined bit rate of the entire group. The determined bit rate of each program is notified to the corresponding encoder 120-1, 120-2, ..., 120-N.

The controller 110 is connected to a control unit (not shown) of the broadcasting system, and inputs group setting information such as change of group settings and addition / deletion of programs. When a group setting is changed, the bit rate distribution is adjusted so that the bit rates before and after the change are stably changed.

The encoders 120-1, 120-2,...
120-N encodes the digital video signals of the respective programs to be input at the bit rate specified by the controller 110 according to a predetermined algorithm. As a result, the digital video signal is compressed. For example, data is compressed by an MPEG method to generate encoded data, and the encoded data is output to the multiplexer 130. At this time, the encoder converts the statistical data used for statistical multiplexing processing such as the complexity of the video substantially corresponding to the generated code amount encoded by the fixed quantization table into the controller 1.
Transmit to 10. Also, the encoders 120-1 and 120-1
, 120-N may send the statistical data to the multiplexer 130 together with the coded data, instead of sending the statistical data directly to the controller 110.
The spare encoder 121 is the encoder 12 described above.
0-1, 120-2, ..., 120-N.

The multiplexer 130 includes the encoders 120-1, 120-2,.
-N, and if necessary, a spare encoder 121, and encoders 120-1, 120-2,.
The coded signal output from 20-N is multiplexed and output.
Also, the encoders 120-1, 120-2,.
If the output data of -N includes statistical data,
This statistical data is sent to the controller 110.

The operation and multiplexing method of the multiplexing apparatus having such a configuration will be described. In a normal state without a group setting change, the encoders 120-1, 120-2,
, 120-N encode the input digital video signal at the bit rate specified by the controller 110. As a result, the digital video signal is compressed. The compressed digital video signal is sent to the multiplexer 130, where it is multiplexed. Statistical data is also generated during the encoding process, and the statistical data is transmitted to the controller 110 directly or via the multiplexer 130. Based on the statistical data, the controller 110 controls each of the encoders 120-1 and 120-1 of the group that performs statistical multiplexing.
Bit rates are assigned to 20-2,..., 120-N. The allocation of the bit rate is performed dynamically so as not to exceed the transmission bit rate given to the group performing the statistical multiplexing. The controller 110 can control bit rate allocation of a plurality of statistical multiplex groups.

When there is a change in the group setting, the controller 110 controls the bit rate distribution so that the bit rate can be stably allocated without any trouble to the broadcasting system even if the group setting changes. I do.

Next, the bit rate control at the time of changing the group setting will be described. FIG. 2 is an example of the transmission rate control of the multiplexing device according to the embodiment of the present invention. This corresponds to program 1 (510), program 2 (52
This is an example in which a program 4 (540) is added to a group consisting of a program 3 (530) and a program 3 (530).

In performing the bit rate control in the digital video signal multiplexing apparatus described above, considering the operation of applying a large number of programs such as a broadcasting station, the setting of the group for performing the statistical multiplexing is dynamic. It is thought to change. To change the group settings, use controller 1
The internal factors that are voluntarily changed on the 10 side are divided into external factors such as failures.

As an internal factor, when a group setting is changed manually or by an operation of an algorithm (the connected device is not changed, but the number of programs is changed), or when a new encoder is connected and a program is added to the group. , To disconnect a connected encoder and remove a program from the group, or to resume a paused encoder operation to add a program to the group,
There is a case where the operation of the connected encoder is suspended and the program is deleted from the group. By changing the group setting, the number of programs or the contents of the programs, that is, the complexity of the video changes.

The external factors include a case where the program is deleted from the group due to a failure of the encoder, and a case where the program is continued but the encoder is changed due to the failure of the encoder. Also in this case, the number of programs or the contents of the programs, that is, the complexity of the video is changed by changing the group setting.

If the number of programs increases during operation, the total bit rate of the group immediately after the change of the group setting may exceed the allowable bit rate depending on the setting of the multiplexer. Assuming that the setting of the group is changed at an arbitrary time, it is desirable to change at a fixed rate without considering the complexity of the video in order to operate the system seamlessly before and after the change. Furthermore, in order to prevent the system from being affected before and after the change, a uniform bit rate is given to each program for a predetermined period before and after the change.

That is, a time (fixed rate control section) 620 that changes at a fixed rate is given before and after the change point 610, and each program is controlled at an equal fixed rate. Assignment of bit rate when changing group setting
The value obtained by dividing the smaller of the total bit rate assigned to each group before and after the group setting change by the larger number of programs set to the group before and after the group setting change is fixed. Bit rate is allocated equally to each program. Expressing this as an equation, the fixed rate is (fixed rate at the time of change) =
(Small value in bit rate given to group before and after change) / (large value in number of programs set in group before and after change).

As described above, by setting the bit rates before and after the change to the fixed rates as described above, the total bit rate of the group does not exceed the allowable bit rate and stably changes when the group setting is changed. . Also, no matter how many connected encoders are in any situation,
It can be controlled seamlessly. Further, the system can be operated stably without breaking down the system even when hardware is changed, such as a failure or addition of an encoder.

As described above, since the bit rate can be stably changed before and after the setting of the group, in a system such as a broadcasting station that operates a large number of programs, the setting change of the group is scheduled. This makes it possible to operate multiplexing of digital video signals in an integrated manner.

The above processing functions can be realized by a computer. In this case, the processing content of the function that the multiplexing apparatus should have is described in a program recorded on a computer-readable recording medium.
Then, by executing this program on a computer, the above processing is realized on the computer. Examples of the computer-readable recording medium include a magnetic recording device and a semiconductor memory. When distributing the program to the market, the program is stored and distributed on a portable recording medium such as a CD-ROM (Compact Disc Read Only Memory) or a floppy (registered trademark) disk, or a computer connected via a network. It can also be stored in a storage device and transferred to another computer via a network. When the program is executed by the computer, the program is stored in a hard disk device or the like in the computer, loaded into the main memory, and executed.

[0030]

As described above, according to the present invention, when the setting of the group for performing the statistical multiplexing process is changed, the bit rate is adjusted so that the bit rate shifts stably before and after the change. Done.

As described above, since the bit rate is adjusted before and after the group setting is changed, it is possible to stably perform the bit rate control without changing the total bit rate of the group beyond the allowable bit rate when the group setting is changed. it can.

Further, in the multiplexing method of the present invention, when there is a change in the group setting, the bit rate is adjusted so that the bit rate shifts stably before and after the change.
As described above, since the bit rate is adjusted before and after the setting change of the group, the bit rate is set stably. Therefore, the total bit rate of the group does not exceed the allowable bit rate.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a multiplexing device according to an embodiment of the present invention.

FIG. 2 is an example of transmission rate control of a multiplexer according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a satellite digital broadcasting system.

[Explanation of symbols]

110 ... controller, 120-1, 120-2, ...,
120-N: encoder, 121: encoder (spare), 130: digital signal multiplexer (multiplexer)

Continued on front page F term (reference) 5C059 KK34 MA00 RB06 RB19 RC09 RC28 SS02 TA60 TB14 TC19 TC37 TD06 UA02 5C063 AA01 AB07 AB11 AC01 CA11 DA01 DA07 DA13 5K028 AA14 BB04 CC05 DD01 DD02 EE03 EE08 KK01 SS05 KK35 LL

Claims (4)

[Claims] 1. A multiplexing apparatus for encoding a digital broadcast program, multiplexing and transmitting the digital broadcast program, and encoding the digital broadcast program to be input according to a predetermined algorithm to generate an encoded signal and a signal at the time of the encoding processing. Encoding means for generating statistical data according to the amount of generated data; and performing bit rate distribution of the encoding means set in the group for each group for performing a predetermined statistical multiplexing process based on the statistical data. Control means for allocating the bit rate so that the bit rate changes stably before and after the setting change of the group when the setting of the group is changed; and the code generated by the coding means set for the group. Multiplexing means for multiplexing the multiplexed signal and outputting the multiplexed signal. 2. The program according to claim 1, wherein the control unit fixes the bit rate for each program for a predetermined period including a point in time when the setting of the group is changed.
The multiplexing device of any of the preceding claims. 3. A program for setting a smaller one of the total bit rates assigned to each group before and after the setting change of the group to the group before and after the setting change of the group. 3. The multiplexing apparatus according to claim 2, wherein a value obtained by dividing a larger one of the numbers is uniformly assigned to each program as a fixed bit rate. 4. A multiplexing method for encoding a digital broadcast program, multiplexing and transmitting the digital broadcast program, and generating statistical data according to the amount of data generated by encoding the digital broadcast program under predetermined conditions. Setting a bit rate for each program set in a group that performs a predetermined statistical multiplexing process based on the statistical data; encoding the digital broadcast program according to the set bit rate; And repeatedly performing the procedure of performing the predetermined statistical multiplexing process.When the setting of the group is changed, the allocation of the bit rate is performed such that the allocation of the bit rate shifts stably before and after the setting change of the group. Multiplex the coded signals of the group, which have been coded according to the set bit rate, and output the multiplexed signals. Multiplexing method characterized by comprising a step of, a.