JPH11177515A - Data encoding device, data multiplexing device, and data encoding and multiplexing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the multiplexing efficiency by means of a transmission rate of a transmission system by describing the information on the inefficient data included in the encoded data at a header part of the encoded data and sampling the inefficient data based on the information on the read inefficient data. SOLUTION: The data streams D8A and D8B which are compressed, encoded and outputted from the encoders 101A and 101B keep a fixed rate respectively by inserting the inefficient data between the header and effective data parts (end of header part) of each of PES packets constituting the streams D8A and D8B. An inefficient data sampling part 122 reads the quantity of inefficient data added to the PES packets of both received streams D8A and D8B out of the header part of every PES packet. The part 122 also samples at a time the inefficient data equivalent to their length based on the detection result of quantity of the inefficient data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

BACKGROUND OF THE INVENTION Prior Art (FIG. 8) Problems to be Solved by the Invention Means for Solving the Problems Embodiments of the Invention (FIGS. 1 to 7) Effects of the Invention

[0003]

The present invention relates to a data encoding device,
Regarding a data multiplexer and a data encoding multiplexer,
For example, it is suitable for application to a transmission device of a digital broadcasting system.

[0004]

2. Description of the Related Art In recent years, various compression encoding methods have been proposed as methods for reducing the amount of video and audio information, and a typical one is MPEG2 (Moving Picture Experts).
There is a method called GroupPhase 2).

[0005] This MPEG2 system is based on ITU-T (Inte
rnational Telecommunication Union-Telecommunicatio
n Standardization Sector: Standardization by bodies such as the International Telecommunication Union Telecommunication Standardization Sector (eg Recommendations, H.
222.0, etc.), and are standardized for the purpose of compressing and encoding video data and audio data, multiplexing and transmitting them.

In the MPEG2 system, a program stream (PS: Program Stream) is used as a data format for multiplexing compression-encoded video data and audio data.
m) (hereinafter referred to as PS data format) and a transport stream (TS: Transpo).
rt Stream) (hereinafter referred to as TS
Data format).

The PS data format is applied when multiplexed video data and audio data are stored in a predetermined digital storage medium, and the TS data format is used when multiplexed video data and audio data are transmitted. Applied to Each stream of the PS data format and the TS data format is a variable-length PES (Packetized Element).
ary Stream) packet is used as a basic element so that both streams can be mutually converted.

Among them, in the PS data format, for example, video data and audio data that have been compression-encoded are respectively converted into PES packets in predetermined units (for example, in units of one picture), and the PES packets obtained as a result are time-division multiplexed. It is defined that a stream of PS packets (a so-called program stream) is formed.

FIG. 8 shows a transmitting apparatus 100 of the digital broadcasting system.
Then, image data D1A and D1B corresponding to a television program are supplied from respective data output units (not shown) corresponding to a plurality of channels to the corresponding encoders 101A and 101B, and the respective encoders 101A and 101B are supplied. , The corresponding image data D1A and D1B are compression-encoded by the MPEG2 system, and the coded data obtained in this manner are sequentially converted to PE data by one picture unit.
Encoding data stream D
31A and D31B are formed and supplied to the multiplexer 102.

[0010] The multiplexing device 102 includes a
When multiplexing the coded data streams D31A and D31B supplied from 1A and 101B, a plurality of PES packets included in the coded data streams D31A and D31B are sequentially buffered in the order in which they arrived. The data is stored in the buffers 103A and 103B and temporarily stored, and is read out in the order of storage in each buffer and transmitted to the multiplexing unit 104.

At this time, each of the buffers 103A and 103B
Supplies the data amount of the stored PES packet to the multiplexing control unit 105 as data storage signals S2A and S2B, respectively, so that the multiplexing control unit 105 outputs the data of the buffers 103A and 103B based on the data storage signals S2A and S2B. Detect occupancy.

Based on the detection result, the multiplexing control unit 105 controls the buffer output control signals S3A and S3 for each of the buffers 103A and 103B before the buffers 103A and 103B exceed the maximum allowable amount.
By sending 3B, the PES packets can be read from the respective buffers 103A and 103B in the order in which they are stored in order, thus avoiding the failure of each of the buffers 103A and 103B due to excessive data accumulation. Can be.

Subsequently, the multiplexing unit 104 controls each buffer 10
Receiving the encoded data streams D31A and D31B obtained from the multiplexing control unit 10
5 receives the multiplexing control signal S4 from each of the coded data streams D31A and D31B, a plurality of PES packets included in each of the coded data streams D31A and D31B are sequentially transmitted in predetermined units (for example, 188-byte data amount). TS (Tran
After that, each TS packet obtained as a result is time-division multiplexed to form a TS stream (transport stream) D32 composed of one TS packet sequence.

Thereafter, the TS stream D32 is modulated by a modulator (not shown) in a predetermined manner, and a transmission signal obtained as a result is transmitted to a broadcasting satellite (not shown) via an antenna.
Sent to Thus, the transmitting device 100
A television program for a plurality of channels can be simultaneously broadcast via a broadcasting satellite.

[0015]

In the transmitting apparatus 100, each of the encoders 101A and 101B
Is adapted to supply the compression-encoded image data (encoded data streams D31A and D31B) to the multiplexer unit at a fixed bit rate. In this case, if the patterns of the input image data D1A and D1B are flat,
Due to the extremely small amount of image information of the image data D1A and D1B, each of the encoders 101A and 101B
Reduce the data amount of the encoded data sequentially generated.

For this reason, each of the encoders 101A and 101B
Is to add dummy data (hereinafter referred to as "invalid data"), which is originally unnecessary for encoding, to valid data in units of bytes when sequentially generating encoded data in PES packets for each picture unit. By doing so, the respective PES
The transmission rates of the encoded data streams D31A and D31B composed of a packet sequence are kept constant.

As described above, each of the encoders 101A and 101A
B is an encoded data stream D with invalid data added
Since 31A and 31B are output, there is a problem that the transmission rate of significant information in the encoded data streams D31A and D31B is reduced by the amount of adding invalid data.

The present invention has been made in view of the above points, and has a simple configuration of a data encoding apparatus and a data multiplexing apparatus capable of improving multiplexing efficiency by effectively utilizing a data transmission rate of a transmission system. And a data encoding and multiplexing device.

[0019]

According to the present invention, in order to solve the above-mentioned problems, when the data encoding device includes invalid data in encoded data, information of the invalid data included in the encoded data is stored in a header of the encoded data. Described and sent to the data multiplexing device, read out the invalid data information from the header of the encoded data input in the data multiplexing device, and extract the invalid data based on the read invalid data information. By doing so, it is possible to more easily detect and extract the invalid data amount.

[0020]

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

In FIG. 1, in which parts corresponding to those in FIG. 8 are assigned the same reference numerals, reference numeral 120 denotes a digital broadcasting system transmitting apparatus to which the present invention is applied, and this transmitting apparatus 120 supports a plurality of channels. The encoders 10 correspond to image data D1A and D1B constituting a television program from respective data output units (not shown).
1A and 101B.

Here, the encoders 101A and 101B have the same configuration, and the encoder 101A inputs the image data D1A to the preprocessor 11A as shown in FIG. The pre-processing unit 11A stores the sequentially input image data D1.
After designating which of three image types of I-picture, P-picture or B-picture to process for each frame image of A, the frame image is encoded according to the image type of the frame image. Rearranged in order, and furthermore, the frame image is 16 pixels × 1
It is divided into macroblocks composed of six lines of luminance signals and color difference signals corresponding to the luminance signals, and this is supplied to the arithmetic circuit 12A and the motion vector detection unit 23A as macroblock data D2A.

The motion vector detecting section 23A calculates a motion vector of each macro block of the macro block data D2A based on the macro block data D2A and the reference image data D14A stored in the frame memory 21A. D18A is sent to the motion compensator 22A.

The arithmetic circuit 12A determines whether the macroblock data D2A supplied from the preprocessor 11A is an intra mode, a forward prediction mode, a forward prediction mode, based on the image type of each macroblock in the macroblock data D2A.
The motion compensation is performed in either the backward prediction mode or the bidirectional prediction mode. Here, the intra mode is a method in which a frame image to be encoded is directly used as transmission data, and the forward prediction mode is a method in which a prediction residual between the frame image to be encoded and a past reference image is transmitted data. It is a method. The backward prediction mode is a method in which a prediction residual between a frame image to be encoded and a future reference image is used as transmission data, and the bidirectional prediction mode is a method in which a frame image to be encoded is This is a method in which a prediction residual between an average value of two prediction images, a reference image and a future reference image, is used as transmission data.

First, the case where the macroblock data D2A is an I-picture will be described. In this case, the macro block data D2A is processed in the intra mode.
That is, the arithmetic circuit 12A outputs the macro block data D2.
The macroblock of A is sent as it is to the DCT (Discrete Cosine Transform, Discrete Cosine Transform) unit 13A as the operation data D3A. The DCT unit 13A performs a DCT transform process on the operation data D3A to convert the operation data D3A into DCT coefficients.
The data is sent to the quantization unit 14A as DCT coefficient data D4A. The quantization unit 14A performs a quantization process on the DCT coefficient data D4A, and sends out the quantized DCT coefficient data D5A to the VLC unit 15A and the inverse quantization unit 18A. At this time, the quantization unit 14A controls the amount of code generated by adjusting the quantization step size in the quantization process according to the quantization control value D21A supplied from the control unit 142A.

The quantized DC sent to the inverse quantization unit 18A
The T coefficient data D5A undergoes an inverse quantization process and is sent to the inverse DCT unit 19A as DCT coefficient data D11A.
The DCT coefficient data D11A is supplied to the inverse DCT unit 19A.
Undergoes an inverse DCT process, and is sent to the arithmetic circuit 20A as arithmetic data D12A, and the reference image data D13A
Is stored in the frame memory 21A.

Next, a case where the macroblock data D2A is a P-picture will be described. In this case, the arithmetic circuit 12A performs a motion compensation process on the macroblock data D2A in one of the intra mode and the forward prediction mode.

When the prediction mode is the intra mode, the arithmetic circuit 12A sends the macroblock of the macroblock data D2A as it is to the DCT unit 13A as the arithmetic signal D3A, as in the case of the I-picture.

On the other hand, when the prediction mode is the forward prediction mode, the arithmetic circuit 12A outputs the macroblock data D
For 2A, a subtraction process is performed using the forward prediction image data D17A supplied from the motion compensation unit 22A.

The forward prediction image data D17A is obtained by referring to the reference image data D13 stored in the frame memory 21A.
A is calculated by performing motion compensation on A according to the motion vector data D18A. That is, in the forward prediction mode, the motion compensator 22 reads the reference image data D13A by shifting the read address of the frame memory 21A according to the motion vector data D18A, and uses the read image data D13A as the forward prediction image data D17A. 20A. The operation circuit 12A subtracts the forward prediction image data D17A from the macroblock data D2A to obtain difference data as a prediction residual, and obtains the operation data D3
A is transmitted to the DCT unit 13A.

The operation circuit 20A includes a motion compensator 22.
A forward prediction image data D17A is supplied from A, and the arithmetic circuit 20 locally reproduces the reference image data D13A (P picture) by adding the forward prediction image data D17A to the arithmetic data D12A, and the frame memory 21A To memorize.

Next, a case where macroblock data D2A of B picture is supplied from the preprocessing unit 11A to the arithmetic circuit 12A will be described. In this case, the arithmetic circuit 12A performs any one of the motion compensation processing of the intra mode, the forward prediction mode, the backward prediction mode, and the bidirectional prediction mode on the macroblock data D2A.

When the prediction mode is the intra mode or the forward mode, the macroblock data S2 is subjected to the same processing as in the case of the P picture described above. However, since the B picture is not used as another predicted reference image, the reference image data D13A is not stored in the frame memory 21A.

On the other hand, when the prediction mode is the backward prediction mode, the arithmetic circuit 12A outputs the macroblock data D
For 2A, a subtraction process is performed using the backward prediction image data D16A supplied from the motion compensation unit 22A.

The backward prediction image data D16A is the reference image data D13 stored in the frame memory 21A.
A is calculated by performing motion compensation on A according to the motion vector data D18A. That is, in the backward prediction mode, the motion compensator 22A reads the reference image data D13A by shifting the read address of the frame memory 21A in accordance with the motion vector data D18A, and uses the read reference image data D13A as the backward prediction image data D16A. 20A. The arithmetic circuit 12A subtracts the backward prediction image data D16A from the macroblock data D2A to obtain difference data as a prediction residual.
The data is transmitted to the DCT unit 13A as 3A.

The operation circuit 20A includes a motion compensator 22.
The backward prediction image data D16A is supplied from A, and the arithmetic circuit 20A locally reproduces the reference image data D13A (B picture) by adding the backward prediction image data D16A to the calculation data D12A. Is not used as another predicted reference image, the reference image data D13A is not stored in the frame memory 21.

When the prediction mode is the bidirectional mode, the arithmetic circuit 12A uses the macroblock data D2A to calculate the forward prediction image data D17A supplied from the motion compensator 22A.
Then, the average value of the backward prediction image data D16A is subtracted to obtain difference data as a prediction residual, and is sent to the DCT unit 13A as operation data D3A.

The operation circuit 20A includes a motion compensator 22.
A supplies the forward prediction image data D17A and the backward prediction image data D16A, and the arithmetic circuit 20A adds the forward prediction image data D17A to the arithmetic data D12A.
The reference image data D13A (B-picture) is generated by adding the average value of A and the backward prediction image data D16A. However, since the B-picture is not used as another prediction reference image, the reference image data D13A is stored in the frame memory. It is not stored in 21A.

Thus, the image data D1A input to the encoding device 101A undergoes motion compensation prediction processing, DCT processing and quantization processing, and is quantized DCT coefficient data D5A.
Is supplied to the VLC unit 15A.

The VLC unit 15A performs a variable length coding process on the quantized DCT coefficient data D5A based on a predetermined conversion table, and sends the resulting data to the buffer unit 141A as variable length coded data D6A. .

As shown in FIG. 3, the buffer section 141A inputs the variable length coded data D6A supplied from the VLC section 15A (FIG. 2) to the buffer memory 50A and stores them in the input order.

The control unit 142A (FIG. 2) uses the occupation amount information D23A supplied from the buffer memory 50A to
Variable length encoded data D6 in buffer memory 50A
A is constantly monitoring the accumulation state of A, and the occupation amount information D2
3A, and generates a quantization control value D21A to generate a quantization control value D21A.
4A, and adjusts the quantization step size in the quantization processing. As a result, the quantization unit 14A generates a data amount according to the data occupancy of the buffer memory 50A so that the buffer memory 50A does not overflow or underflow.

In FIG. 3, the buffer memory 50A reads the variable-length coded data D6A stored therein by a data transmission control signal D22A supplied from the control unit 142A (FIG. 2) every one picture, and reads this. The buffer output data D20A is sent to the invalid data adding unit 60A at a predetermined bit rate. Here, when the data amount of the encoded data (variable length encoded data D6A) stored in the buffer memory 50A becomes extremely small in accordance with the characteristics such as the picture of the image to be encoded, a predetermined read rate (transmission rate) is obtained. Rate) cannot be secured. Therefore, in this case, the invalid data adding unit 6
0A is an amount of stuffing byte data (dummy data) necessary to maintain a predetermined bit rate in accordance with the data occupancy of the buffer memory 50A based on the occupancy information D23A supplied from the buffer memory 50A. Is added to the buffer output data D20A, and this is output as fixed-length encoded data D60A to the packet forming unit 70A.

If the buffer output data D20A has a sufficient data amount to maintain a predetermined bit rate, the invalid data adding unit 60A outputs the buffer output data D20A.
No dummy data (hereinafter referred to as invalid data) is added to 20A. At this time, the invalid data adding unit 60
A supplies the generation information of invalid data added to the fixed-length encoded data D60A to the invalid data length description data generation unit 80A as invalid data generation information D61A. The invalid data length description data generating section 80A creates invalid data length description data D80A indicating the data length of invalid data added to the fixed length encoded data D60A based on the invalid data generation information D61A, and forms a packet forming section. 70A.

In the packet forming section 70A, the fixed length coded data D60A is packetized by adding a predetermined header to a PES (Packetized Elemantary Stream) and transmitted as a PES packet D70A. In this case, the packet forming unit 70A outputs a PES packet sequence in which a plurality of PES packets are connected to the output data stream D.
8A to the multiplexer 121 (FIG. 1).

At this time, the packet forming section 70A
Based on the invalid data length description data D80A supplied from the invalid data length description data generator 80A, the presence or absence of invalid data and the length of invalid data are described in the PES packet D70A.

That is, FIGS. 4A, 4B and 5 show the structure of the PES packet D70A of the present invention.
A packet start code A1 having a length of 3 bytes is assigned to the head of the ES packet D70A, followed by a stream ID (Identifier) A2 having a length of 1 byte and PES packet length data A3 having a length of 2 bytes. . Where P
The ES packet length data A3 indicates the length L1 from the PES packet length data A3 onward to the end of the PES packet D70A. By referring to the value indicated by the PES packet length data A3, the PES packet D70A It is made to know the length of.

In the PES packet D70A, the PES
PES consisting of 2 bytes following packet length data A3
Fill in the header flag A4. PES header flag A4
Describes information such as scramble information and copyright information in the PES packet D70A.
Here, the last 1 [bit] of the PES header flag A4 is defined as a PES extension flag, and the PES extension flag A4E indicates the presence or absence of the PES extension A7.
In describing the invalid data length in the present invention, the PE
A4E = 1 indicating that the PES extension data A7 exists is assigned to the S extension flag A4E.

Next, PES header length data A5 having a length of 1 [byte] is described. The PES header length data A5 starts with the valid data A from the PES header length data A5.
12 shows the length L2 up to the beginning of the data, and the start position of the valid data A12 can be known by referring to the value indicated by the PES header length data A5.

Following the PES header length data A5, the PES
Assign head field A6. The PES header field A6 is a PTS (Presentation Time Stamp).
) And DTS (Decoding Time Stamp), etc., describing various data related to the PES packet D70A, and the data length varies according to the contents of the PES packet D70A.

Then, following the PES header field A6, the PES extension data A7 is described. Here, in the PES extension data A7, a 1-bit PES extension flag 2 (A7E) is defined by the MPEG2 standard, and the PES extension flag 2 (A7E) is a PES extension field A8 (FIG. 4B). ). In addition, MPE
The G2 standard does not specify a specific use of the PES extension field A8. In the present invention, P
The presence or absence of invalid data is described using the ES extension flag 2 (A7E), and the data length of invalid data is described in the PES extension field A8.

When no invalid data is generated, PE
When the S extension data A7 exists, as shown in FIG. 4A, the PE extension flag A4E = 1 and the PE
A7E = 0 indicating that the PES extension field A8 does not exist is described for the S extension flag 2 (A7E), and PE
The valid data A12 is allocated following the S extension data A7, and the description of the PES packet D70A is completed.

When no invalid data is generated and the PES extension data A7 does not exist, the PES extension flag A4E is set to 0 as shown in FIG. In this case, the valid data A follows the PES header field A6.
12 are allocated.

On the other hand, when invalid data occurs,
That is, in FIG. 4B, the PES extension flag 2
(A7E) is described with A7E = 1 indicating that the PES extension field A8 exists, and the PES extension data A7
Describes a PES extension field A8. Where PE
The S extension field A8 includes identification byte data A9 and invalid data length data A10. The identification byte data A9 is an area having a length of 1 [byte] in which a predetermined content is written. By detecting the identification byte data A9, the data length of the invalid data length data A10 can be reliably identified. I have. The invalid data length data A10 has a length of 1 [byte], and indicates the data length from the invalid data length data A10 to the valid data A12, that is, L3 which is the data length of the invalid data A11. Therefore,
By referring to the value indicated by the invalid data length data A10, the data length of the invalid data A11 can be known without counting the data length of the invalid data A11. Here, the invalid data length data A1
The value of 0 is described based on the invalid data length description data D80A sent from the invalid data length description data generation unit 80A (FIG. 3). Thus, the invalid data A11 and the valid data A12 are described after the invalid data length data A10, and the description of the PES packet D70A is completed.

Thus, the output data stream D8A composed of a PES packet sequence to which invalid data A11 is added as required from the encoder 101A is output to the multiplexer 121 (FIG. 1) while maintaining a constant transmission rate. .

Although the above description has been given of the first encoder 101A, the other encoders 101B and 124 have the same configuration.

The multiplexing device 121 is provided with each encoder 101A.
And the output data stream D8 supplied from 101B
When multiplexing A and D8B, a plurality of PES packets included in each of the output data streams D8A and D8B are respectively associated with corresponding buffers 103A and 103B.
The data stored in the buffers 103A and 103B are read out in the order of storage, and stored in the buffer 103A and 103B.
Sent to

At this time, each of the buffers 103A and 103B
Supplies the data amount of the stored PES packet to the multiplexing control unit 123 as the data storage signals S2A and S2B, respectively, so that the multiplexing control unit 123 outputs the data of the buffers 103A and 103B based on the data storage signals S2A and S2B. Detect occupancy.

Based on this detection result, the multiplexing control unit 123 sends the buffer output control signals S3A and S3A to the buffers 103A and 103B before the buffers 103A and 103B exceed the maximum allowable capacity.
By sending 3B, the PES packets can be read out from the respective buffers 103A and 103B in the order in which they were stored sequentially, and thus each buffer 103A and 103B can be read out due to excessive data accumulation.
Can be avoided.

Subsequently, the invalid data extracting unit 122 outputs the PES extension flag (A4) described in the header of each PES packet of the output data streams D8A and D8B sequentially read from the buffers 103A and 103B.
E) and the PES extension flag 2 (A7E) (FIG. 4), the presence or absence of invalid data is determined. If invalid data exists, invalid data length data A10 (FIG. 4)
By referring to (B)), the invalid data amount (data length) described in the PES packet is detected. Subsequently, the invalid data extracting unit 122 sequentially extracts invalid data from the PES packet based on the detected invalid data length, and then outputs valid data streams D8A ′ and D8B ′ including a header unit and a valid data unit. This is sent to the multiplexing unit 127.

More specifically, as shown in FIGS. 6A and 6B, the PES packet sequences P _A1 , P _A2 , and P E forming the output data stream D8A output from the encoder 101A.
P _A3 , P _A4 ... (P _A1 , P _A2 , P _A3 , P _A4 ... Are the PES packet D70 described above with reference to FIGS. 4 and 5, respectively).
A), for example, invalid data portions ND _A2 and ND _A4 are assigned to PES packets P _A2 and P _A4 (ND _A2 and ND _A4 each represent an area where the invalid data A1 described above with reference to FIG. 4B is allocated). Are formed, and the encoder 1
PES packet strings P _B1 , P _B2 , P _B3 , P _B4 forming an output data stream D8B output from the data stream 01B.
(P _B1 , P _B2 , P _B3 , P _B4 ... _{Correspond to} FIGS. 4 and 5, respectively.
Represents a PES packet D70B having the same configuration as the above-described PES packet D70A). For example, the PES packets P _B1 , P _B2 and P _B3 have invalid data portions ND _B1 and ND.
_{When B2} and ND _B3 are formed, the invalid data sampling unit 122 outputs the output data streams D8A and D8B.
For each header part H _A1 of the incoming PES packet,
The presence / absence of invalid data is determined from H _A2 , H _A3 , H _A4 and H _B1 , H _B2 , H _B3 , H _B4 .

Thus, as shown in FIGS. 6C, 6D and 6E, the invalid data extracting section 122 outputs data streams D8A and D8B each composed of a PES packet sequence.
Of the invalid data portions ND _A2 , ND _A4 and ND _B1 , ND
_B2 and ND _B3 do not pass through the invalid data A11 (FIG. 4B), and valid data A12 other than the invalid data A11.
And only the header section is output.

At this time, the invalid data extracting unit 122
The PES extension flag 2 (A7E) is set to 0, the identification byte (A9) and the invalid data length (A10) are deleted, and when there is no use of PES extended data other than the invalid data length description, the PES extension flag (A7E) is set. After A4E) is returned to 0, this is output to the multiplexing unit 127. Incidentally, as the identification byte (A9) and the invalid data length (A10) are deleted, the description contents of the PES packet length (L1) and the PES header length (L2) are changed in the invalid data extracting unit 122.

As a result, the invalid data extracting unit 12
2 are valid data streams D8A 'and D
8B ', as shown in FIG. 6 (G) and (H), the invalid data section ND _A2, ND _A4, and ND _B1, ND _B2, ND _B3 a sampling ivy content, data length is short Natsuta PES packet P _A2 ', _PA4 ' and _PB1 ', _PB2 ', _PB3 '.

As shown in FIG. 6E, the invalid data extracting section 122 outputs the invalid data added to each PES packet from the header of each PES packet of each of the input output data streams D8A and D8B. Is read out and transmitted to the multiplexing control unit 123 as invalid data amount information S10 for each predetermined number of PES packets. In this case, the invalid data amount represented by the invalid data amount information S10 may be either for one PES packet or for two or more PES packets. The invalid data amount obtained for each predetermined number of PES packets in this manner is sequentially accumulated in the multiplexing control unit 123.

The valid data streams D8A 'and D8B' output from the invalid data extracting section 122 have a smaller total data amount because the invalid data sections ND _A2 , ND _A4 and ND _B1 , ND _B2 and ND _B3 are extracted. The output data amount is output to the multiplexing unit 127 in a state where the data is extracted, and the extracted data amount is recognized by the multiplexing control unit 123 based on the invalid data amount information signal S10.

The multiplexing control unit 123 provides a buffer 103A.
And a multiplexing control signal S16 is transmitted to the multiplexing unit 127 based on the multiplexing plan obtained according to the data occupancy amount of the multiplexing unit 103B. The multiplexing unit 127 generates a fixed data length TS from the effective data streams D8A 'and D8B' having the PES configuration.
A (Transport Stream) packet is generated and multiplexed to generate a multiplexed stream (transport stream) D15, which is output to transmission equipment (not shown) including a transmission antenna.

Incidentally, as the invalid data is extracted in the invalid data extracting section 122, it becomes necessary to rewrite time information for the valid data streams D8A 'and D8B'. Accordingly, the multiplexing control unit 123 adds new time information by transmitting the multiplexing control signal S16 to the multiplexing unit 127.

In addition to the above configuration, the transmitting apparatus 120
Service data D1X such as, for example, personal computer communication data and information service data is supplied from a data output unit (not shown) to the encoder 124 as needed, and the encoder 1
At 24, the output data stream D8X is formed by converting the coded data sequentially generated into PES packets for each predetermined data unit by the above-described compression coding according to the MPEG2 method, and the output data stream D8X corresponding to the output data stream D8X is formed. A buffer 125 is provided. The service data D1X is data that can be stored without having to be transmitted in real time, and can be used as needed after being stored on the receiving side.

In this buffer 125, a plurality of PES packets included in the output data stream D8X are stored and accumulated in the order of arrival. At this time, the buffer 125 gives the data amount of the stored PES packet to the multiplexing control unit 123 as the data storage signal S12, so that the multiplexing control unit 123 outputs the data storage signal S1.
2, the amount of data stored in the buffer 125 can be recognized.

Here, when the multiplexing control unit 123 receives the multiplexing request signal S15 for the service data from the external system controller 126, the multiplexing control unit 123 determines that the data amount of the service data D1X stored in the buffer 125 is the minimum that can be transmitted. It is determined whether or not only the amount of data is secured. If the amount is secured, a buffer output control signal S13 for designating a data amount equal to or less than the total amount of invalid data extracted by the invalid data extracting unit 122.
To the buffer 1 in which the service data D1X is stored.
25.

Based on the buffer output control signal S13, the buffer 125 reads out the stored PES packets in the order in which they are stored, in the order in which they are stored, by the amount of data that can be allocated to the invalid data amount, and reads this from the service data stream D8X '.
To the multiplexing unit 127.

At this time, the multiplexing control unit 123 prepares a new multiplexing plan to multiplex the service data stream D8X 'in addition to the valid data streams D8A' and D8B 'output from the invalid data extracting unit 122. Generate and respond accordingly to buffers 103A and 103B.
Of the output data streams D8A and D8B, and multiplexing in the multiplexing unit 127.

Thus, the multiplexing unit 127 outputs the valid data stream D supplied from the invalid data extracting unit 122.
8A 'and D8B' and a fixed length TS from the service data stream D8X 'supplied from the buffer 125.
By generating packets and multiplexing them, a multiplexed stream (transport stream) D16 including service data (D1X) is generated and output to a transmission facility (not shown) including a transmitting antenna.

The multiplexed stream D15 or D16 output from the multiplexing unit 127 is modulated by a modulator (not shown) of the transmission equipment in a predetermined manner, and the transmission signal obtained as a result is broadcast via an antenna. It is transmitted to a satellite (not shown). Thus, the transmitting device 120
In addition to the television programs for a plurality of channels, service data D1X in place of the extracted invalid data is multiplexed, and these are simultaneously broadcast via a broadcasting satellite.

When there is no service data D1X to be transmitted, the multiplexing control unit 123 multiplexes an invalid data stream corresponding to the invalid data amount into a valid data stream in the multiplexing unit 127.

In the above configuration, the output data streams D8A and D8B output as a result of the compression encoding in the encoders 101A and 101B are provided between the header part and the effective data part (header part) of the PES packet constituting each. At the end of the data), a constant rate is maintained by inserting invalid data (stuffing byte data). In this case, invalid data is inserted into an arbitrary PES packet with an arbitrary data length according to the amount of encoded data generated in the encoders 101A and 101B.

The invalid data extracting section 122 calculates the amount of invalid data added to each PES packet of the incoming output data streams D8A and D8B by using each PES packet.
Read from the header of the packet. Thus, the invalid data extracting unit 122 can detect the amount of invalid data simply by referring to the header of the PES packet. Accordingly, the invalid data (for example, data that is not used as valid data, such as “00” or “FF”) is directly read from the invalid data portion and counted, without performing the complicated processing that is required when the invalid data is read. The data amount of invalid data added to the area corresponding to the header can be detected easily and in a short time only by referring to the header arriving before.

Further, the invalid data extracting unit 122
When the data amount (data length) of the invalid data is detected from the header of the ES packet, the invalid data can be extracted by the data length at a time based on the detection result. As a result, cumbersome processing when extracting invalid data while directly detecting the invalid data is avoided, and the time required for the processing for extracting invalid data is shortened accordingly.

Thus, according to the above configuration, it is possible to detect the amount of invalid data in the invalid data extracting unit 122 and detect the amount of invalid data without requiring a processing time. Can be simplified, and the processing time can be shortened.

In the above-described embodiment, as described above with reference to FIG.
Although the case where 0A is provided inside the encoder 101A has been described, the present invention is not limited to this. For example, as shown in FIG. 7 in which parts corresponding to those in FIG. The description data generator may be provided outside the encoder 101A.

In this case, the invalid data adding unit 60A uses the invalid data length description information 90A of the external invalid data length entry unit 90A as invalid data generation information D61A as invalid data generation information D61A added to the fixed-length encoded data D60A. The data is supplied to the data generator 81A. The invalid data length description data generation unit 81A is based on the invalid data generation information D61A, and the invalid data length description data D8 representing the data length (data amount) of the invalid data added to the fixed length encoded data D60A.
1A is created and supplied to the header reconstruction unit 85A.

In the packet structuring unit 71A, the fixed-length coded data D60A is added with a predetermined header and converted into a PES packet, and then output to the header reconfiguring unit 85A as a PES packet D71A. Header reconstructing unit 85A
Is PES according to the invalid data length description data D81A.
The presence or absence of invalid data and the invalid data length (invalid data amount) are described in the format described above with reference to FIG. 4 for the packet D71A, and this is sent to the multiplexer as the PES packet D90A.

As described above, if the invalid data length entry section 90A is connected to the outside of the encoder, the invalid data entry section 90A can be connected as necessary to describe information on invalid data. .

In the above-described embodiment, the case has been described where the output data streams D8A and D8B output from the encoders 101A and 101B are data streams each composed of a PES packet sequence.
The present invention is not limited to this, and the present invention can be applied to the case of outputting in various other data units by describing the invalid data amount in the header section for each data unit.

In the above-described embodiment, the case where the present invention is applied to the transmitting apparatus 120 of the digital broadcasting system based on the MPEG2 system has been described. However, the present invention is not limited to this, and the present invention is not limited to this. It can be applied to various other transmitting devices.

[0087]

As described above, according to the present invention, when the data encoding device includes invalid data in the encoded data, the information of the included invalid data is described in the header of the encoded data to perform data multiplexing. To the gasifier,
The data multiplexing device reads invalid data information from the header of the coded data input, and extracts invalid data based on the read invalid data information. The extraction process can be more easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a transmitting device using an encoding device and a multiplexing device according to the present invention.

FIG. 2 is a block diagram showing a configuration of an encoding device according to the present invention.

FIG. 3 is a block diagram showing a configuration of a buffer section of the encoding device according to the present invention.

FIG. 4 is a schematic diagram showing a PES packet configuration according to the present invention.

FIG. 5 is a schematic diagram showing a PES packet configuration when there is no PES extension data.

FIG. 6 is a schematic diagram used to explain a process of extracting an invalid data portion;

FIG. 7 is a block diagram showing a buffer section and an externally attached invalid data entry section of an encoding device according to another embodiment.

FIG. 8 is a block diagram showing a configuration of a conventional transmission device.

[Explanation of symbols]

50A buffer memory, 60A invalid data adding section, 70A, 71A packet forming section, 80A, 81
A: invalid data length description data generating section, 85A: header reconstructing section, 90A: invalid data length entry section, 101
A, 101B, 124 encoder, 120 transmitter, 121 multiplexer, 122 invalid data extracting unit, 123 multiplex control unit, 127 multiplex unit, 140A Encoding section, 141A buffer section,
142A... Control unit.

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[Procedure amendment]

[Submission date] December 17, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H04N 7/08 H04N 7/08 Z 7/081

Claims (6)

[Claims] 1. A data encoding apparatus for encoding input data and outputting the encoded data in a predetermined encoded data unit, wherein when the encoded data includes invalid data, information of the included invalid data is transmitted. A data encoding apparatus comprising an invalid data information description means described in a header of the encoded data. 2. The data encoding apparatus according to claim 1, wherein the invalid data information is information indicating the presence or absence of the invalid data and information indicating the invalid data amount. 3. A data multiplexing apparatus for multiplexing and outputting data streams of a plurality of channels, wherein when a packet of a predetermined coded data unit forming said data stream includes invalid data, information of said invalid data is transmitted to said invalid data. Invalid data information reading means for reading from the header of the packet containing data; invalid data extracting means for extracting the invalid data based on the invalid data information read by the invalid data information reading means; Multiplexing means for multiplexing and outputting a data stream from which data has been extracted. 4. The data multiplexing apparatus according to claim 3, wherein the invalid data information is information indicating the presence or absence of the invalid data and information indicating the invalid data amount. 5. A plurality of data encoding units for respectively encoding input data of a plurality of channels and outputting the encoded data in units of predetermined encoded data, and the encoded data output from each of the data encoding units. A data multiplexing device having a data multiplexing device for multiplexing and outputting a data stream of a plurality of channels composed of a unit sequence, wherein the data coder has a function when the coded data contains invalid data. Invalid data information description means for describing the information of the included invalid data in a header of the encoded data, wherein the data multiplexing device unit is configured to transmit the predetermined encoded data unit of the predetermined encoded data unit forming the data stream. When the packet contains invalid data, the information of the invalid data is read from the header of the packet containing the invalid data. Data information reading means, invalid data extracting means for extracting the invalid data based on the invalid data information read by the invalid data information reading means, and a data stream from which the invalid data is extracted are multiplexed. And a multiplexing means for outputting the data. 6. The data encoding and multiplexing apparatus according to claim 5, wherein the information on the invalid data is information indicating the presence or absence of the invalid data and information indicating the invalid data amount.