JP3429652B2 - Digital coding and multiplexing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention multiplexes one or more program data (video data, audio data, etc.) into another bit stream (including program data),
The present invention relates to a digital encoding / multiplexing device for outputting as one bit stream.

[0002]

2. Description of the Related Art MPEG2 (ISO / IEC1381
In the multiplexing method represented by 8), a plurality of program data (for example, audio data and video data)
The protocol for multiplexing into one transport stream is defined (ITU-T Recommendation H.222.0).

FIG. 2 shows a conventional example of such a digital encoding / multiplexing apparatus, and FIG. 3 shows an example of its operation. In addition,
2 and 3 both contain two program data,
The figure shows the case of multiplexing into one transport stream.

The digital encoding / multiplexing device shown in FIG. 2 encodes two program data A and B into a transport stream, and outputs an audiovisual image (AV).
It includes encoders 1A and 1B and a multiplexer (MUX) 2 that multiplexes the output transport streams TS (A) and TS (B) into one transport stream TS (C) and outputs the multiplexed transport stream TS (C). .

The multiplexer 2 multiplexes the transport streams A and B input from the audio-visual (AV) encoders 1A and 1B at a data transmission rate twice as high as that of each transport stream. It is configured to output as a transport stream TS (C).

[0006]

However, in the case of the digital coding / multiplexing apparatus having such a structure, there is a problem that the bit rate must be changed at the time of multiplexing as shown in FIG. Moreover, when such a multiplexing process (change of the data transmission rate) is performed, there is a problem that the information that each program data has so that the correct clock can be reproduced on the decoding side is lost due to the multiplexing.

The present invention has been made in consideration of the above points, and a digital encoding capable of multiplexing program data without changing the data transmission rate of the bit stream to be multiplexed. It is intended to propose a multiplexer.

[0008]

In order to solve such a problem, according to the present invention, (1) it is detected whether or not a code includes a meaningless redundant code, and it is included. When the redundant code is detected, redundant code detecting means for outputting a detection signal indicating the detection period of the redundant code, and (2) the input program data are compression-encoded and output as a packet data stream. The compression coding means and (3) the transmission timing of the packet data stream input from the compression coding means is adjusted based on the detection signal given from the redundant code detection means, and significant packet data and packet data of the bit stream are adjusted. Delay means to avoid contention with significant packet data in the stream, and (4) redundant code period or redundant code period appearing in the multiplexed bitstream. The idle time, insert a significant packet data inputted from the delay means, the Bittosu
No significant packet data is inserted in the stream
Insert a redundant code in the redundant code period or idle time,
A digital coding and multiplexing apparatus is provided with a multiplexing means for outputting a multiplexed bitstream having the same transmission rate as the bitstream.

As described above, the program data is compression-encoded to generate a free time in the packet data stream,
By delay control using the idle time, it is possible to avoid contention of significant packet data with other bitstreams to be multiplexed, and to obtain the significance obtained from the program data in the redundant code period or idle time appearing in the other bitstream. By inserting packet data, multiplexing can be performed without changing the transmission rate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a digital coding and multiplexing apparatus according to the present invention will be described below in order with reference to the drawings.

(A) First Embodiment (A-1) First Embodiment Device Configuration FIG. 1 shows a functional block configuration of a digital encoding and multiplexing device according to the first embodiment.

This digital encoding / multiplexing apparatus comprises an audiovisual (AV) encoder 11, a null packet generator 12,
It is composed of a multiplexer (MUX) 13.

The audio-visual (AV) encoder 11 compresses and encodes the program data A (acoustic data or video data) into packets, and then the transport stream TS.
(A) is a means for outputting. The compression rate here is controlled based on the control signal CTL, and the data rate after compression (the amount of information generated per unit time) is the data transmission rate (transport streams TS (A) and TS (C)). (Transmission rate of)).

The null packet generator 12 is a redundant packet generating means for generating a bit stream called null packet (Null) which does not include audiovisual (AV) information.

The multiplexer (MUX) 13 has a null packet (N) in the idle time of the transport stream TS (A).
and the transport stream TS
(C) is a multiplexing unit that outputs a compression rate corresponding to the data transmission rate to the audio-visual (AV) encoder 11 as a control signal CTL. The data transmission rate input to the multiplexer (MUX) 13 and the data transmission rate output from the multiplexer (MUX) 13 are the same, and the same clock is used on the input side and the output side. It is configured to be operable.

(A-2) Multiplexing Operation by the First Embodiment Apparatus Next, the multiplexing operation of the digital coding and multiplexing apparatus which is the first embodiment apparatus will be described.

First, the digital encoding / multiplexing apparatus inputs the inputted program data A to the audio-visual (AV) encoder 11. Audiovisual (AV) encoder 11
Compresses the program A at a compression rate indicated by the control signal CTL, packetizes it, and outputs it as a transport stream TS (A). The packet represented by “A” in the upper part of FIG. 4 corresponds to this.

In FIG. 4, the data rate of the transport stream TS (A) (the amount of information generated per unit time) is calculated as the data transmission rate (data transmission rate of the transport streams TS (A) and TS (C)). ) 1 /
This is an example of the case defined in 4.

When the significant packet compressed and encoded in this way is input from the audio-visual (AV) encoder 11, the multiplexer (MUX) 13 sets it at the same data transmission rate as that at the time of input. Output. On the other hand, when the compression-coded significant packet is not input (that is,
When there is no input), the null packet (Null) input from the null packet generator 12 is inserted in the empty period. As a result, as shown in the lower part of FIG. 4, the transport stream TS (C) in which the null packet (Null) that is the redundant bit appears at an arbitrary timing is output.

(A-3) Effects of the First Embodiment As described above, according to the first embodiment, the data rate of the program data A (the amount of information generated per unit time).
Are compressed so that the data transmission rate of the transport stream TS (C) output from the multiplexer 13 is equal to or lower than the data transmission rate, and redundant packets are inserted in the free time generated by the compression processing. Thus, it is possible to realize a digital coding and multiplexing apparatus that can generate a transport stream TS (C) that can be easily re-multiplexed.

Further, in multiplexing, since it is not necessary to change the data transmission rate between the input and output of the multiplexer 13, there is a problem that has occurred in the past, that is, the time required for speeding up the data transmission rate and clock reproduction. Information loss, etc. can be effectively avoided.

(B) Second Embodiment (B-1) Second Embodiment Device Configuration FIG. 5 shows a functional block configuration of a digital encoding and multiplexing device according to a second embodiment. Note that FIG.
The same parts as and are indicated by the same reference numerals.

The digital coding / multiplexing apparatus includes an audiovisual (AV) encoder 11, a null packet generator 12, a delay device 21, a null packet detector 22, and a multiplexer (MUX).
23. That is, the configurations of the audiovisual (AV) encoder 11 and the null packet generator 12 are the same as those in the first embodiment. Therefore, the other components will be described below.

The delay device 21 is a first-in first-out memory (F) having a sufficient capacity to store one or a plurality of packets.
IFO memory), and is a means for outputting the delayed output as a transport stream TS (A) ′. However, the delay time of the other bit stream (here, in the relation to be multiplexed with the transport stream TS (A) input to the delay device 21 (here,
It is not constant because it is determined according to a race condition generated with the transport stream TS (B) and an internal storage state of the FIFO memory.

For example, when the null packet detection signal provided from the null packet detector 22 is significant (for example, "H" level) and there are no packets waiting to be sent,
While the delay device 21 reads the input packet at the same time as writing (at this time, the delay time is zero), when there is a packet waiting for transmission, the delay device 21 reads the packet with the longest waiting time. (The delay time of the packet output at this time varies depending on the waiting time until transmission).

On the other hand, the null packet detection signal provided from the null packet detector 22 is not significant (for example, "L").
Level), the delay device 21 stores the input packet at the address following the end of the packet waiting to be sent, because a race condition may occur.

Therefore, in the delay device 21, both the write address and the read address can be arbitrarily designated.
IFO memory is used.

The null packet detector 22 adds a null packet (N) to the transport stream TS (B) which is in a relationship of being multiplexed with the transport stream TS (A) '.
It is a means for detecting whether or not a bit stream that does not include audio-visual (AV) information called "ull)" is included and for giving a null packet detection signal indicating the detection result (timing) to the delay unit 21.

When a null packet (Null) is detected, the null packet detector 22 sets the null packet detection signal to a significant level (“H” level) and outputs the null packet (N).
null) is not detected, the null packet detection signal is set to the insignificant level (“L” level).

The null packet detector 22 and the delay device 21
By the existence of the above, it is possible to avoid the situation in which the significant packet of the program data A and the significant packet of the transport stream TS (B) are input to the input of the multiplexer (MUX) 23 at the same timing.

The multiplexer (MUX) 23 receives the transport stream TS (A) 'and a null packet (Nul).
It is a means for inputting the bit stream of 1) and the transport stream TS (B), multiplexing them, and outputting them as one transport stream TS (C).

The multiplexer (MUX) 23 selects one of the transport streams TS (A) 'and TS (B), whichever contains the significant packet, and selects the significant packet as the transport stream TS ( However, when both streams do not include a significant packet, a null packet (Null) is output at the packet timing.

In the first embodiment, the multiplexer (MUX) 23 instructs the audio-visual (AV) encoder 11 as a control signal CTL, which is a compression rate corresponding to the data transmission rate. This is the same as the case of the multiplexer (MUX) 23.

(B-2) Multiplexing operation by the second embodiment device Next, the multiplexing operation of the digital coding and multiplexing device which is the second embodiment device will be described. Here, an example of the operation will be described with reference to FIG. Note that in FIG. 6, a null packet (Nu packet) is set as the bit stream to be multiplexed.
transport stream TS as obtained by the apparatus of the first embodiment in which 11) is included at any timing
(B) shall be used.

Also, this digital encoding and multiplexing apparatus has two data inputs unlike the apparatus of the first embodiment, and one of the data inputs has a stream (hereinafter, "It is called" internal device stream ".)
And a bit stream processed by another device (hereinafter, referred to as “other device stream”) is input to the other data input.

First, the audiovisual (AV) encoder 11
When significant data is input as the program data A (audio data or video data) which is a stream in the device itself, it is packetized after compression encoding at the compression rate designated by the control signal CTL, and is used as the transport stream TS (A). Output. This transport stream TS
In FIG. 6, (A) is represented by a significant packet “A” that appears discretely.

On the other hand, the null packet detector 22 uses the transport stream TS (B) which is a stream of another device.
If you enter, the current input packet
It is judged whether it is 1) or not. This transport stream T
In FIG. 6, S (B) is represented by a packet sequence of “B” and “Null”.

In the case of FIG. 6, since the head packet (shown at the left end of FIG. 6) of the stream of another device is the significant packet “B”, it is at the “L” level indicating that it is not a null packet (Null). The null packet detection signal is output from the null packet detector 22 to the delay device 21. The delay device 21 to which this null packet detection signal is input inhibits the reading of the significant packet “A” of the in-device stream input to the delay device 21 at the same timing, and operates to hold the data content.

Therefore, the only significant packet input to the multiplexer (MUX) 23 for the first packet is the significant packet "B" input from the other device stream, and the relevant packet "B" is the transport for the period. It will be output as the stream TS (C).

At the next packet timing (second packet timing from the left in FIG. 6), since the input of the program data A, which is a stream in the own device, is not input due to data compression, the audiovisual (AV The encoder 11 does not output any packet during the period. This is represented by a blank in FIG.

On the other hand, since the null packet (Null) is input to the transport stream TS (B) which is the stream of the other device, the null packet detector 22 which has detected the existence of the null packet (Null).
Outputs a null packet detection signal of “H” level to the delay unit 21.

As a result, the delay unit 21 removes the read prohibition of the significant packet "A" taken in during the previous packet period and multiplexes the significant packet "A" as a packet of the transport stream TS (A) '. Bowl (MUX)
To 23.

That is, the significant packet "A" delayed by one packet period is the transport stream TS.
(A) ′ is output to the multiplexer (MUX) 23. In FIG. 6, this correspondence is represented by an oblique arrow from the transport stream TS (A) to the transport stream TS (A) ′.

Thus, the significant packet input to the multiplexer (MUX) 23 for the timing is only the significant packet "A" input one packet before as the in-device stream, and the packet "A" is It is output as the transport stream TS (C) in the period. The significant packet “A” shown in the lower part of FIG. 6 corresponds to this.

Further next packet timing (in FIG. 6,
At the third packet timing from the left), significant data is input as the program data A which is a stream in the own device, while a null packet (N
ull) is input. Therefore, the delay unit 21 reads the significant packet “A” input from the audio-visual (AV) encoder 11 without delay time and outputs it as a transport stream TS (A) ′ to the multiplexer (MUX) 23. .

As a result, the multiplexer (MUX) 23 outputs the significant packet "A" of its own device stream as the transport stream TS (C) in the period.

It should be noted that, as in the subsequent packet timing, the input of the program data A, which is a stream in the own device, is not input, and the transport stream TS (B), which is a stream of another device, is a null packet (N
If there is no significant packet input to the multiplexer (MUX) 23 in any of the streams, the null packet (Null) input from the null packet generator 12 is the transport stream TS.
(C) will be output.

By repeating the above operation, the significant packet "A" of the own apparatus stream is re-multiplexed from the multiplexer (MUX) 23 during the null packet (Null) input period of the stream of another apparatus. Packet sequence (...
"B", "A", "A", "Null", "B",
"A", "A" ...) is the transport stream TS
(C) will be output.

When the transport stream TS (B), which is the other device stream, is program data compressed and coded like the transport stream TS (A), the transport stream TS
The null packet (Null) generated by the null packet generator 12 is input to the multiplexer (M) during the non-input period (blank period in which no significant packet exists) of both (A) and TS (B).
UX) 23.

(B-3) Effect of Second Embodiment As described above, according to the second embodiment, the multiplexer 23 is used.
Since the input side and the output side can perform the multiplexing process using the same data transmission rate, it is possible to realize a digital coding and multiplexing device in which the multiplexing process is easier than in the past.

Since the number of packets generated by the audio-visual (AV) encoder 11 can be freely increased or decreased by controlling the compression rate, the free time required for re-multiplexing can be set freely. You can do it.

Moreover, at the time of multiplexing, information other than the bit stream on the multiplexed side (transport stream TS (B) in this case) (whether there is a null packet (Null)) is not used. The control itself can be simplified.

(C) Third Embodiment (C-1) Third Embodiment Device Configuration FIG. 7 shows a functional block configuration of a digital encoding and multiplexing device according to a third embodiment. In addition, in FIG.
, And the same parts are designated by the same reference numerals.

The digital coding / multiplexing apparatus includes an audiovisual (AV) encoder 11, a null packet generator 12, a delay unit 21 ', a null packet detector 22, and a multiplexer (MU).
X) 23 and a PCR (Program Clock Reference) changing unit 31.

That is, the delay device 21 'and the PCR changer 3
Other parts except 1 have the same device configuration as the device of the second embodiment. Therefore, here, the delay devices 21 'and P
Only the CR changer 31 will be described, and description of other components will be omitted.

The delay device 21 ′ is means corresponding to the delay device 21 which constitutes the digital encoding and multiplexing apparatus according to the second embodiment, and its basic configuration is the same as that of the delay device 21. That is, the delay unit 21 'is composed of a delay unit including a first-in first-out memory (FIFO memory) having a sufficient capacity to store one or a plurality of packets.

The difference between the delay device 21 'and the delay device 21 is that a significant level (for example,
The point is that a function of giving a delay time signal Td giving "H" level) to the PCR changer 31 is added. This is to prevent the time information shift caused by the delay processing from affecting the decoding, as will be described later.

The PCR changer 31 uses the PCR (Program Cl
ock Reference: Program time reference reference value), which is the time information for setting or calibrating the value of the basic synchronization signal that serves as the time reference on the decoding side to the value intended by the decoder.
It is a means for changing according to the delay amount.

Therefore, the PCR changer 31 is constructed so as to be able to correct it based on the delay time signal Td input from the delayer 21 'located in the preceding stage. Since the PCR changer 31 is a means for such an application, the PCR changer 31 does not include a PCR-containing packet (hereinafter, "non-PC").
R packet ”. ) Is configured to pass without any treatment. In addition, PCR
A packet including "" will be referred to as a "PCR packet" below.

FIG. 8 shows a configuration example of the PCR changer 31. As shown in FIG. 8, the PCR changer 31 includes a PCR determination circuit 32, a PCR register 33, a timer 34,
It is composed of an adder 35 and a selector 36. Further, the PCR changer 31 has an input end for inputting the transport stream TS (A) 'which is the output of the delay device 21' and an input end for inputting the delay time signal Td for each packet. Have

In the PCR judging circuit 32, when the input packet is P
It is means for determining whether the packet is a CR packet or a non-PCR packet. If it is determined that the packet is a PCR packet, P
The CR determination circuit 32 outputs a selection signal to switch the input to be selected by the selector 36 to the adder 35 side, takes out the PCR value in the PCR packet, and stores it in the PCR register 33. On the other hand, when it is determined that the packet is a non-PCR packet, the PCR determination circuit 32 determines that the selector 36
A selection signal is output so as to switch the input to be selected to the delay device 21 'side.

The PCR register 33 is a temporary storage means for temporarily holding the PCR value extracted from the PCR packet.

The timer 34 is means for operating while the delay time signal Td is at a significant level (for example, "H" level) and counting the delay time. The count value is reset when the delay time signal Td changes to a useless level (for example, “L” level) or when the delay time signal Td that has once changed to a useless level changes to a significant level again. .

The adder 35 is means for adding the count value of the timer 34 to the PCR value stored in the PCR register 33 and outputting it.

The selector 36 selectively outputs either the non-PCR packet input from the delay unit 21 'or the PCR packet with the corrected PCR value, based on the selection signal given from the PCR determination circuit 32. Is.

(C-2) Multiplexing Operation by the Third Embodiment Apparatus Next, the multiplexing operation of the digital coding and multiplexing apparatus which is the third embodiment apparatus will be explained. Here, an example of the operation will be described with reference to FIG. In the case of FIG. 9 as well,
As the transport stream TS (B), a stream packet containing a null packet (Null) at an arbitrary timing is used.

As can be seen from FIG. 9, the basic operation of the third embodiment device is basically the same as that of the second embodiment device having the same basic configuration.

That is, the packet of the program A which is the stream in the own apparatus and the transport stream TS (B) which is the stream of the other apparatus are input at the same timing.
When the packet of the transport stream TS (B) is a significant packet, the packet of the program A is delayed by prioritizing the packet of the transport stream TS (B), while the null packet (Nul) is added to the transport stream TS (B).
When 1) is input, the multiplexer 23 selectively outputs the delayed packet of the in-device stream or the significant packet of the in-device stream input at the same timing.

Therefore, here, the operation part peculiar to the third embodiment, particularly the operation when the PCR packet is input as the program data A which is the stream in the own device, will be described.

First, when there is no competition between the PCR packet output from the audio-visual (AV) encoder 11 and the significant packet of the transport stream TS (B) which is the other device stream (that is, the null packet detector). 22
When a null packet (Null) is detected in
Will be described.

In this case, the PC input to the delay unit 21 '
The R packet is immediately given to the PCR changer 31 without waiting time. At this time, the delay time signal Td input to the PCR changer 31 does not change to a significant level (for example, “H” level) even once, and remains at a dead level (for example, “L” level). is there. Therefore, the count value output from the timer 34 remains zero, and the output value of the adder 35 is the same as the value when input to the PCR changer 31.

As a result, the PCR packet whose PCR value has not been changed is input to the multiplexer (MUX) 23 as the transport stream TS (A) ″ output from the PCR changer 31. It is re-multiplexed and output as the transport stream TS (C).

Next, when the PCR packet output from the audio-visual (AV) encoder 11 and the significant packet of the transport stream TS (B) which is another device stream compete with each other (that is, the null packet detector). If no null packet (Null) is detected in 22)
Will be described. This operation is the packet timing operation shown in the third and second parts from the right in FIG.

In this case (third packet timing from the right in FIG. 9), the PCR packet input to the delay unit 21 'is prohibited from being output while being written in the predetermined address. On the other hand, the significant packet “B” of the transport stream TS (B) input at the same timing is selected by the multiplexer (MUX) 23 and output as it is as the transport stream TS (C). .

At this time, the delay unit 21 'outputs the delay time signal Td at a significant level ("H" level).

However, the next packet timing (see FIG. 9)
In the middle and second packet timing from the right), the transport stream TS (B) which is the other device stream.
Since a null packet (Null) is input as, the null packet detector 22 outputs a null packet detection signal of a significant level (“H” level) to the delay device 21 ′ and is stored in the delay device 21 ′. PCR packet is P
It is read to the CR changer 31. Simultaneously with this reading, the delay time signal Td output from the delay device 21 '
Changes to an ineffective level (“L” level).

Here, when the PCR changer 31 determines that the input packet is a PCR packet by the PCR determination circuit 32, the PCR value is loaded into the PCR register 33, and the output of the current packet timing is as follows. The selection signal is output to the selector 36 so that the PCR packet having the changed PCR value is output.

Thereafter, the PCR value fetched from the input PCR packet is read from the PCR register 33, and the delay time is measured while the PCR packet is delayed by the delay unit 21 '. The count value of the timer 34 is added by the adder 35. As a result, the PCR value of the PCR packet is corrected to the correct value.
Then, the PCR packet having the corrected PCR value is given from the selector 36 to the multiplexer 23, and is output as the transport stream TS (C).

(C-3) Effects of Third Embodiment As described above, also in the third embodiment, it is necessary to change the data transmission rate between the input and output streams, as in the case of the second embodiment. Thus, it is possible to realize a digital coding and multiplexing device which can easily perform a multiplexing process. Further, by changing the compression rate, the number of packets generated by the audio-visual (AV) encoder 11 can be freely increased or decreased, so that the idle time can be freely set in preparation for the re-multiplexing.

Moreover, in the transport stream after re-multiplexing which is the output of the apparatus of the third embodiment, P
Since the CR value has been changed to the correct value, it is possible to reproduce the correct clock based on the correct PCR value without jitter due to re-multiplexing even when the transport stream is decoded. It is possible to eliminate the adverse effect on the decoder side due to the time variation of the clock.

(D) Other Embodiments In the first embodiment, a single device for generating a transport stream suitable for re-multiplexing from program data will be described, and the second and third embodiments will be described. In the above, a single device that multiplexes other program data into a bitstream consisting of such a transport stream has been described, but as shown in FIG.
The apparatus according to the first embodiment and the apparatus according to the second embodiment may be cascade-connected, or the apparatus according to the first embodiment and the apparatus according to the third embodiment may be cascade-connected to construct a multiplexing system.

By doing so, it is possible to easily construct a system that can multiplex more program data without changing the data transmission rate and output it as one transport stream TS (C). it can.

Of course, the configuration is not limited to that shown in FIG. 10, and the configurations of the first to third embodiments can be arbitrarily combined.

In each of the second and third embodiments, the bit stream for multiplexing the program data A, which is the in-device stream, is described as the other device stream, and the signal path thereof is not mentioned at all. But,
Such a stream may be transmitted from a remote device connected via a network. Therefore, the system shown in FIG. 10 is not necessarily limited to the system constructed at the same point.

Further, in the third embodiment, PCR
The case where the PCR value is changed to the correct value by adding the delay time measured by the timer 34 provided in the changer 31 to the PCR register 33 has been described. A circuit and a counter for measuring the delay time of the PCR packet detected by the determination circuit are provided, and the count value measured by the counter is used as the PCR changer 31.
(Instead of the delay time signal Td). Even with such a configuration, as in the third embodiment, P
The CR value can be changed to the correct value.

In each of the first to third embodiments, the compression rate at the time of compression encoding performed by the audio / video (AV) encoder 11 is controlled by the multiplexer (MUX) 13 or 23. Although described as the configuration, the data rate after compression (the amount of information generated per unit time) is the transport stream TS output from the multiplexer 13 or 23.
It is not limited to this as long as the relationship below the data transmission rate of (C) is satisfied. That is, the compression coding may be performed at a fixed compression rate determined in advance, or the control means for controlling the entire system may control this.

[0087]

As described above, according to the present invention, another bit stream to be multiplexed is controlled by the delay control utilizing the free time in the packet data stream generated by the compression encoding in the compression encoding means. avoiding conflicts significant packet data and inserts a significant packet data obtained from the program data to the redundant code period or idle time appear on the other bit streams, the Bittosu
No significant packet data is inserted in the stream
By inserting the redundant code in the redundant code period or the vacant time, it is possible to easily realize the digital coding and multiplexing apparatus that can execute the multiplexing process without changing the transmission rate.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a digital encoding and multiplexing apparatus that is a first embodiment apparatus.

FIG. 2 is a block diagram showing a configuration of a conventional device.

FIG. 3 is a diagram showing an example of a multiplexing operation of a conventional device.

FIG. 4 is a diagram showing an example of a multiplexing operation performed by the device of the first exemplary embodiment.

FIG. 5 is a block diagram showing a configuration of a digital encoding and multiplexing apparatus which is an apparatus according to a second exemplary embodiment.

FIG. 6 is a diagram showing an example of multiplexing operation by the apparatus of the second embodiment.

FIG. 7 is a block diagram showing a configuration of a digital encoding and multiplexing apparatus that is an apparatus according to a third exemplary embodiment.

FIG. 8 is a block diagram showing a detailed configuration of a PCR changer.

FIG. 9 is a diagram showing an example of multiplexing operation by the apparatus of the third embodiment.

FIG. 10 is a diagram showing an example of a system constructed by the apparatuses of the first to third embodiments.

[Explanation of symbols]

11 ... Audio-visual (AV) encoder, 12 ... Null packet generator, 13, 23 ... Multiplexer (MUX), 21, 2
1 '... delay device, 22 ... null packet detector, 31 ... PC
R changer, 32 ... PCR determination circuit, 33 ... PCR register, 34 ... Timer, 35 ... Adder, 36 ... Selector.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-168150 (JP, A) JP-A-10-173622 (JP, A) JP-A-56-64532 (JP, A) JP-A-4- 330885 (JP, A) Japanese Patent Laid-Open No. 8-138316 (JP, A) Yasuhiro Miki, Special Feature 5 Actual and Challenges of Experiments for Digital Data Transmission of Image / Audio, Interface, Japan, 1996, Sep, 1999, p. ． 154-160 (58) Fields investigated (Int.Cl. ⁷ , DB name) H04J 3/00 H04N 7/08 H04N 7/081 JISST file (JOIS)

Claims (2)

(57) [Claims] 1. A detection is made as to whether or not a code includes a meaningless redundant code in the input bitstream, and if such a code is included, the detection period of the redundant code is set every time the redundant code is detected. Redundant code detecting means for outputting the detection signal shown, compression encoding means for compressing and encoding the input program data and outputting as a packet data stream, and transmission timing for the packet data stream input from the compression encoding means. Appearing in the bitstream, and delay means for adjusting based on the detection signal given from the redundant code detecting means to avoid conflict between the significant packet data of the bitstream and the significant packet data in the packet data stream. During the redundant code period or the idle time, the significant packet input from the delay means is input. Data and insert significant packets on the above bitstream.
The above redundant code period where data is not inserted or when it is empty
A digital encoding / multiplexing apparatus, characterized by comprising a redundant code inserted therebetween and outputting a multiplexed bitstream having the same transmission rate as the bitstream. 2. The digital encoding and multiplexing apparatus according to claim 1, wherein the clock reproduction information included in the packet data stream input from the delay means to the multiplexing means is a significant packet including the clock reproduction information. A digital encoding and multiplexing apparatus further comprising clock reproduction information updating means for updating data in accordance with the delay time of the data in the delay means.