JPH11163817A - Digital encoding multiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To multiplex program data without adding any change to a data transmission rate about a bit stream on the side of being multiplexed by inserting a redundant code stream into an idle time that appears in a packet data stream from a compression encoding means and outputting it as a multiplexed bit stream. SOLUTION: An acoustic video encoder 11 compresses a program A with compressibility that is indicated by a control signal CTL, makes it a packet and outputs it as a transport stream TS (A). When the stream TS (A) is inputted from the encoder 11, a multiplexer 13 outputs it in a transmission rate that is the same with the time of being inputted and when the stream TS (A) is not inputted, it inserts a null packet Null sent from a null packet generator 12 that is a redundant packet generating means into an idle period. Consequently, it is possible to generate a transport stream TS (C) which is easy to be remultiplexed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention multiplexes one or a plurality of program data (video data, audio data, etc.) into another bit stream (including program data),
The present invention relates to a digital encoding and multiplexing device that outputs a single 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) are
Rules for multiplexing into one transport stream are defined (ITU-T Recommendation H.222.0).

FIG. 2 shows a conventional example of such a digital encoding and multiplexing apparatus, and FIG. 3 shows an example of its operation. In addition,
FIGS. 2 and 3 both show two program data,
This shows a case where the data is multiplexed into one transport stream.

A digital encoding and multiplexing apparatus shown in FIG. 2 encodes two program data A and B into a transport stream and outputs the encoded audio and video (AV).
It comprises encoders 1A and 1B and a multiplexer (MUX) 2 for multiplexing and outputting the transport streams TS (A) and TS (B) as one output to one transport stream TS (C). .

A multiplexer 2 multiplexes each of the transport streams A and B input from the audio / video (AV) encoders 1A and 1B at a data transmission rate twice 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 and multiplexing apparatus having such a configuration, 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 information that each program data has so that an accurate clock can be reproduced on the decoding side is damaged by the multiplexing.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and has been made in consideration of the above-mentioned problems, and has been made in consideration of the above-described problems. A multiplexing device is proposed.

[0008]

According to a first aspect of the present invention, there is provided a compression encoding unit for compressing and encoding input program data and outputting it as a packet data stream; ) Redundant code generation means for generating redundant codes having no meaning in codes and outputting them as redundant code streams, and (3) inputting from the redundant code generating means to idle time appearing in the packet data stream inputted from the compression encoding means. Multiplexing means for inserting a redundant code to be output and outputting a multiplexed bit stream having the same transmission rate as the packet data stream.

As described above, since a redundant bit stream is generated by multiplexing a redundant code in a free time in a packet data stream obtained by compression coding, the program data is multiplexed with another bit stream. When multiplexing, it is possible to change to a multiplexed bit stream suitable for multiplexing without changing the transmission rate.

In order to solve such a problem, according to the second aspect of the present invention, (1) an input bit stream includes:
A redundant code detecting unit that detects whether or not the code includes a meaningless redundant code, and when the redundant code is included, each time a redundant code is detected, a redundant code detecting unit that outputs a detection signal indicating a detection period of the redundant code; (2) compression encoding means for compressing and encoding the input program data, and outputting the packet data stream as a packet data stream; and (3) transmission timing for the packet data stream inputted from the compression encoding means,
Delay means for adjusting based on the detection signal given from the redundant code detection means to avoid competition between significant packet data in the bit stream and significant packet data in the packet data stream; and (4) redundancy appearing in the multiplexed bit stream. The digital coding and multiplexing apparatus is provided with a multiplexing unit that inserts significant packet data input from the delay unit into the code period or the idle time and outputs the multiplexed bit stream having the same transmission rate as the bit stream. I do.

Thus, the free time is generated in the packet data stream by compressing and encoding the program data,
The delay control using the idle time avoids competition of significant packet data with another bit stream to be multiplexed, and the redundant code period or significant time obtained from the program data during the idle time appearing in the other bit stream. By inserting packet data, multiplexing can be performed without changing the transmission rate.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a digital encoding and multiplexing apparatus according to the present invention.

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

This digital encoding and multiplexing apparatus includes an audio / video (AV) encoder 11, a null packet generator 12,
A multiplexer (MUX) 13 is provided.

The audio / video (AV) encoder 11 compresses and encodes the program data A (audio data or video data) into packets, and transports the transport stream TS.
This is a means for outputting as (A). Note that 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) depends on the data transmission rate (the transport streams TS (A) and TS (C)). Is set to be equal to or less than the transmission rate.

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

The multiplexer (MUX) 13 transmits a null packet (N) to the idle time of the transport stream TS (A).
ul) and the transport stream TS
The multiplexing means outputs the result as (C), and instructs the audio / video (AV) encoder 11 as a control signal CTL at a compression rate corresponding to the data transmission rate. 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 input side and the output side use the same clock. It is configured to be operable.

(A-2) Multiplexing Operation by the First Embodiment The multiplexing operation of the digital encoding and multiplexing apparatus as the first embodiment will be described.

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

FIG. 4 shows the data rate (the amount of information generated per unit time) of the transport stream TS (A) as the data transmission rate (the data transmission rate of the transport streams TS (A) and TS (C)). 1)
4 is an example in the case where it is determined.

When a significant packet compressed and encoded as described above is input from the audio / video (AV) encoder 11, the multiplexer (MUX) 13 converts the significant packet at the same data transmission rate as at the time of input. Output. On the other hand, when a significant packet that has been compressed and encoded is not input (that is,
When there is no input), a null packet (Null) input from the null packet generator 12 is inserted into the empty period. As a result, as shown in the lower part of FIG. 4, a transport stream TS (C) in which a null packet (Null), which is a 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)
Is compressed so as to be equal to or lower than the data transmission rate of the transport stream TS (C) output from the multiplexer 13, and redundant packets are inserted within the idle time generated by the compression processing. And a digital encoding and multiplexing apparatus that can generate a transport stream TS (C) that can be easily remultiplexed.

In multiplexing, since it is not necessary to change the data transmission rate between the input and output of the multiplexer 13, the conventional problems, that is, the increase in the data transmission rate and the time required for clock recovery. Loss of information can be effectively avoided.

(B) Second Embodiment (B-1) Second Embodiment Configuration of Apparatus FIG. 5 shows a functional block configuration of a digital encoding and multiplexing apparatus according to a second embodiment. In FIG. 5, FIG.
The same reference numerals are given to the same parts as in FIG.

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

The delay unit 21 has a first-in first-out memory (F) having a capacity sufficient to store one or a plurality of packets.
This is a means for outputting a delay output as a transport stream TS (A) ′. However, the delay time is equal to the other bit stream (here, the bit stream is multiplexed with the transport stream TS (A) input to the delay unit 21).
It is not constant because it is determined in accordance with a race condition occurring with the transport stream TS (B)) and the 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 is no packet waiting to be transmitted,
The delay unit 21 reads the input packet simultaneously with writing (at this time, the delay time is zero). If there is a packet waiting to be transmitted, the delay unit 21 reads the packet with the longest waiting time. (The delay time of the packet output at this time varies according to 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").
In the case of (level), the delay unit 21 stores the input packet in the address following the end of the packet waiting to be transmitted, assuming that a race condition may occur.

For this reason, the delay unit 21 has an F which can arbitrarily designate both the write address and the read address.
An IFO memory is used.

The null packet detector 22 adds a null packet (N) to the transport stream TS (B) which is multiplexed with the transport stream TS (A) '.
This is a means for detecting whether or not a bit stream called “ull” and not including audiovisual (AV) information is included, and providing 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 sets the null packet (N
When “ull” is not detected, the null packet detection signal is set to an insignificant level (“L” level).

The null packet detector 22 and the delay unit 21
, The significant packet of the program data A and the significant packet of the transport stream TS (B) are prevented from being input to the input of the multiplexer (MUX) 23 at the same timing.

The multiplexer (MUX) 23 includes a transport stream TS (A) ′ and a null packet (Nul).
1) A means for inputting the bit stream of 1) and the transport stream TS (B), multiplexing these, and outputting as one transport stream TS (C).

The multiplexer (MUX) 23 selects one of the transport streams TS (A) ′ and TS (B) that contains a significant packet, and transfers the significant packet to the transport stream TS ( C), but when both streams do not include a significant packet, a null packet (Null) is output at the packet timing.

The first embodiment is different from the first embodiment in that the multiplexer (MUX) 23 instructs the audio / video (AV) encoder 11 as a control signal CTL at 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 The multiplexing operation of the digital encoding and multiplexing apparatus as the second embodiment will be described. Here, an example of the operation will be described with reference to FIG. In FIG. 6, a null packet (Nu) is used as a bit stream to be multiplexed.
11) is included at an arbitrary timing, and the transport stream TS as obtained by the device of the first embodiment.
(B) shall be used.

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

First, the audio / video (AV) encoder 11
When significant data is input as the program data A (audio data or video data), which is a stream in the own device, it is packetized after compression encoding at a compression ratio specified by the control signal CTL, and is converted into a transport stream TS (A). Output. This transport stream TS
FIG. 6A shows a significant packet “A” that appears discretely in FIG.

On the other hand, the null packet detector 22 outputs a transport stream TS (B) which is another device stream.
Is input, the current input packet becomes a null packet (Nul
1) It is determined whether or not. This transport stream T
In FIG. 6, S (B) is represented by a packet string of “B” and “Null”.

In the case of FIG. 6, since the head packet (shown on the left end in FIG. 6) of the stream of the other device is a significant packet "B", the "L" level indicating that it is not a null packet (Null). A null packet detection signal is output from the null packet detector 22 to the delay unit 21. The delay unit 21 that has received the null packet detection signal operates to prohibit the reading of the significant packet “A” of the stream in its own device input to the delay unit 21 at the same timing, and to hold the data content.

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

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

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

As a result, the delay unit 21 releases the read prohibition of the significant packet “A” captured in the previous packet period, and multiplexes the significant packet “A” as a packet of the transport stream TS (A) ′. Container (MUX)
23.

That is, the significant packet “A” delayed by one packet period is added to the transport stream TS.
(A) 'is output to the multiplexer (MUX) 23. In FIG. 6, this correspondence is indicated by oblique arrows 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 a stream in the own device, and the packet “A” is It will be 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.

The next packet timing (in FIG. 6,
At the third packet timing from the left), significant data is input as 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 out the significant packet “A” input from the audio-video (AV) encoder 11 without delay time, and outputs it to the multiplexer (MUX) 23 as a transport stream TS (A) ′. .

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

As in the subsequent packet timing, the input of the program data A, which is a stream in the own apparatus, is not input, and the transport stream TS (B), which is another apparatus stream, is a null packet (N).
In the case of (ull), there is no significant packet input to the multiplexer (MUX) 23 for any of the streams, so the null packet (Null) input from the null packet generator 12 is used as the transport stream TS.
(C) will be output.

By repeating the above operations, the multiplexer (MUX) 23 remultiplexes the significant packet "A" of the stream in the own apparatus during the null packet (Null) input period of the stream of the other apparatus. Packet sequence (…
"B", "A", "A", "Null", "B",
"A", "A" ...) are the transport streams TS
(C) will be output.

If the transport stream TS (B), which is another device stream, is program data that has been compression-encoded in the same manner as the transport stream TS (A), the transport stream TS (B)
The null packet (Null) generated by the null packet generator 12 in the non-input period (blank period in which no significant packet exists) in both (A) and TS (B) is transmitted to the multiplexer (M).
UX) 23.

(B-3) Effects of the Second Embodiment As described above, according to the second embodiment, the multiplexer 23
Can perform multiplexing processing on the input side and the output side using the same data transmission rate, so that it is possible to realize a digital coding and multiplexing apparatus that can easily perform multiplexing processing as compared with the related art.

Since the number of packets generated by the audio / video (AV) encoder 11 can be freely increased or decreased by controlling the compression ratio, the free time required for remultiplexing can be freely set. Can do.

In addition, at the time of the multiplexing, information other than information on the bit stream to be multiplexed (here, the transport stream TS (B)) (the presence or absence of a null packet (Null)) is not used. The control itself can be simplified.

(C) Third Embodiment (C-1) Third Embodiment Configuration of Apparatus FIG. 7 shows a functional block configuration of a digital encoding and multiplexing apparatus according to a third embodiment. Note that FIG.
, The same parts are denoted by the same reference numerals.

The digital encoding and multiplexing apparatus includes an audio / video (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) changer 31.

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

The delay unit 21 'is a means corresponding to the delay unit 21 constituting the digital encoding and multiplexing apparatus according to the second embodiment, and its basic configuration is the same as that of the delay unit 21. That is, the delay unit 21 'is constituted by 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 of the delay unit 21 ′ from the delay unit 21 is that a significant level (for example,
The difference is that a function of giving the delay time signal Td giving the “H” level) to the PCR changer 31 is added. This is to prevent time information deviation caused by the delay processing from affecting the decoding, as described later.

The PCR changing unit 31 has a PCR (Program Cl
time information for setting or calibrating a value of a basic synchronization signal, which is a time reference on the decoding side, to a value intended by the decoder side, which is called an “ock reference: program time reference value”.
This is a means for changing according to the delay amount.

For this reason, the PCR changer 31 is configured so as to be able to correct it based on the delay time signal Td input from the delay unit 21 'located at the preceding stage. Note that, since this is a means intended for such a use, the PCR changer 31 transmits a packet that does not include a PCR (hereinafter, “non-PC
R packet ". ) Is configured to pass through without any processing. In addition, PCR
Is hereinafter referred to as a “PCR packet”.

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 comprises an adder 35 and a selector 36. Further, the PCR changer 31 has an input terminal for inputting the transport stream TS (A) ′ which is an output of the delay unit 21 ′, and an input terminal for inputting the delay time signal Td for each packet. Have.

The PCR determination circuit 32 determines that the input packet is P
This is a means for determining whether the packet is a CR packet or a non-PCR packet. Here, when 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, extracts the PCR value from the PCR packet, and stores it in the PCR register 33. On the other hand, if it is determined that the packet is a non-PCR packet, the PCR determination circuit 32
The selection signal is output so as to switch the input to be selected to the delay device 21 'side.

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

The timer 34 is a means which operates while the delay time signal Td is at a significant level (for example, "H" level) and counts the delay time. The count value is reset when the delay time signal Td changes to an ineffective level (for example, “L” level) or when the delay time signal Td once changed to the ineffective level changes to the significant level again. .

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

The selector 36 selectively outputs one of the non-PCR packet input from the delay unit 21 ′ and the PCR packet after the PCR value correction, based on the selection signal supplied from the PCR determination circuit 32. It is.

(C-2) Multiplexing Operation by Third Embodiment Next, the multiplexing operation of the digital encoding and multiplexing apparatus according to the third embodiment will be described. Here, an example of the operation will be described with reference to FIG. In the case of FIG.
As the transport stream TS (B), a stream 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 is basically the same as that of the second embodiment having the same basic configuration.

That is, a packet of the program A, which is a stream in the own device, which is input at the same timing, and a transport stream TS (B) which is a stream of another device.
Are both significant packets, the packet of the program A is delayed by giving priority to the packet of the transport stream TS (B), while the null packet (Nul) is added to the transport stream TS (B).
When l) is input, the multiplexer 23 selectively outputs the delayed packets of the internal device stream or the significant packets of the internal device stream input at the same timing.

Therefore, here, an operation part specific to the third embodiment, particularly, an operation in the case where a PCR packet is input as program data A which is a stream in the own device will be described.

First, when there is no competition between the PCR packet output from the audio / video (AV) encoder 11 and a significant packet of the transport stream TS (B) which is another device stream (that is, a 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 supplied to the PCR changer 31 without any waiting time. At this time, the delay time signal Td input to the PCR changer 31 never changes to a significant level (for example, “H” level) and remains at an indefinite 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 in which no change has been made to the PCR value is input to the multiplexer (MUX) 23 as the transport stream TS (A) ″ output from the PCR modifier 31. To be remultiplexed and output as a transport stream TS (C).

Next, when a PCR packet output from the audio / video (AV) encoder 11 and a significant packet of the transport stream TS (B), which is another device stream, compete with each other (that is, a null packet detector). 22 when a null packet (Null) is not detected)
Will be described. This operation is the operation of the packet timing shown in the third and second from the right in FIG.

In this case (the third packet timing from the right in FIG. 9), the output of the PCR packet input to the delay unit 21 'is prohibited while being written at a 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, a delay time signal Td of a significant level ("H" level) is output from the delay unit 21 '.

However, the next packet timing (FIG. 9)
In the middle, second packet timing from the right), the transport stream TS (B) which is another device stream
, A null packet detection signal of a significant level (“H” level) is output from the null packet detector 22 to the delay unit 21 ′ and stored in the delay unit 21 ′. PCR packet is P
It is read out to the CR changer 31. At the same time as this reading, the delay time signal Td output from the delay unit 21 'is output.
Changes to the inaction level (“L” level).

When the PCR change circuit 31 determines that the input packet is a PCR packet by the PCR determination circuit 32, the PCR changer 31 takes in the PCR value into the PCR register 33 and outputs the current packet timing as follows: The selection signal is output to the selector 36 so as to output the PCR packet having the changed PCR value.

Thereafter, the PCR value fetched from the input PCR packet is read out 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. Thereby, the PCR value of the PCR packet is corrected to a correct value.
Then, the PCR packet having the corrected PCR value is provided from the selector 36 to the multiplexer 23, and output as the transport stream TS (C).

(C-3) Effect of Third Embodiment As described above, in the third embodiment, as in the second embodiment, it is necessary to change the data transmission rate between input and output streams. A digital coding and multiplexing apparatus that can easily perform multiplexing processing can be realized. Also, by changing the compression ratio, the number of packets generated by the audio-video (AV) encoder 11 can be freely increased or decreased, so that the idle time can be freely set in preparation for the re-multiplexing.

Further, in the transport stream after remultiplexing, which is the output of the third embodiment, P
Since the CR value has been changed to a correct value, even when decoding the transport stream, it is possible to reproduce an accurate clock based on an accurate PCR value without jitter due to re-multiplexing. 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 remultiplexing from program data will be described. Second and third embodiments Has described a single device for multiplexing other program data into a bit stream composed of such a transport stream, but as shown in FIG.
A multiplexing system may be constructed by cascading the devices of the second embodiment and the devices of the second embodiment, or by cascading the devices of the first embodiment and the devices of the third embodiment.

In this way, it is possible to easily construct a system capable of multiplexing more program data without changing the data transmission rate and outputting the same as one transport stream TS (C). it can.

Of course, the configuration is not limited to the configuration shown in FIG. 10, but may be a configuration in which the first to third embodiments are arbitrarily combined.

In each of the second and third embodiments, the bit stream for multiplexing the program data A, which is a stream in the own apparatus, is described as another apparatus stream, and the signal path 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.

In the third embodiment, the PCR
The case where the PCR value is changed to a 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. Circuit and a counter for measuring the delay time of the PCR packet detected by the determination circuit, and the count value measured by the counter is changed by the PCR changer 31.
(Instead of the delay time signal Td). Even with this configuration, as in the third embodiment, P
The CR value can be changed to a correct value.

In each of the first to third embodiments, the compression ratio at the time of compression coding performed by the audio / video (AV) encoder 11 is controlled by the multiplexer (MUX) 13 or 23. Although described as a configuration, the data rate after compression (the amount of generated information per unit time) is determined by 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, compression encoding may be performed at a predetermined fixed compression ratio, or control may be performed by a control unit that controls the entire system.

[0089]

As described above, according to the first aspect, a multiplexed bit stream is generated by multiplexing a redundant code in a free time in a packet data stream generated by compression encoding in a compression encoding unit. By doing so, it is possible to easily realize a digital encoding and multiplexing apparatus that can output a multiplexed bit stream that can be multiplexed with another bit stream without changing the transmission rate.

Further, as described above, according to the second aspect of the present invention, the delay control using the vacant time in the packet data stream generated by the compression encoding by the compression encoding means makes it possible to multiplex other packets to be multiplexed. By avoiding contention of significant packet data with the bit stream and inserting significant packet data obtained from program data into the redundant code period or idle time appearing in the other bit stream, multiplexing can be performed without changing the transmission rate. Digital multiplexing and multiplexing apparatus capable of executing the conversion process can be easily realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating 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 illustrating an example of a multiplexing operation of a conventional device.

FIG. 4 is a diagram illustrating an example of a multiplexing operation performed by the device according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a digital encoding and multiplexing apparatus as a second embodiment apparatus.

FIG. 6 is a diagram illustrating an example of a multiplexing operation performed by the device according to the second embodiment;

FIG. 7 is a block diagram illustrating a configuration of a digital encoding and multiplexing apparatus that is a third embodiment apparatus.

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

FIG. 9 is a diagram illustrating an example of a multiplexing operation performed by the device according to the third embodiment.

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

[Explanation of symbols]

11 audio video (AV) encoder, 12 null packet generator, 13, 23 multiplexer (MUX), 21, 2
1 ': delay unit, 22: null packet detector, 31: PC
R changer, 32 ... PCR determination circuit, 33 ... PCR register, 34 ... Timer, 35 ... Adder, 36 ... Selector.

Claims (4)

[Claims] 1. Compression encoding means for compressing and encoding input program data and outputting it as a packet data stream, redundant code generating means for generating a redundant code having no meaning in the code and outputting it as a redundant code stream, The redundant code input from the redundant code generating means is inserted into the idle time appearing in the packet data stream input from the compression encoding means, and a multiplexed bit stream having the same transmission rate as the packet data stream is output. A digital encoding and multiplexing device comprising multiplexing means. 2. The digital encoding and multiplexing apparatus according to claim 1, wherein said multiplexing means sets a compression rate of said program data in said compression and encoding means based on a transmission rate of said multiplexed bit stream. A digital coding and multiplexing device characterized by setting. 3. An input bit stream detects whether a redundant code having no meaning is included in a code. If the redundant bit code is included, a detection period of the redundant code is set every time a redundant code is detected. Redundant code detection means for outputting a detection signal indicating the compression data, compression encoding means for compressing and encoding the input program data and outputting it as a packet data stream, and transmission timing for the packet data stream inputted from the compression encoding means. And delay means for adjusting contention based on a detection signal given from the redundant code detection means to avoid competition between significant packet data of the bit stream and significant packet data in the packet data stream. In the redundant code period or the idle time, a significant packet input from the delay means is used. Multiplexing means for inserting multiplexed data and outputting a multiplexed bit stream having the same transmission rate as the bit stream. 4. The digital encoding and multiplexing apparatus according to claim 3, wherein clock recovery information included in a packet data stream input from said delay means to said multiplexing means is converted into a significant packet including said clock recovery information. A digital coding and multiplexing apparatus further comprising a clock reproduction information updating means for updating data in accordance with a delay time in the delay means.