JP3907422B2 - Data multiplexing transmission method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data multiplexing transmission method and apparatus for multiplexing and transmitting external data such as a character signal and a net cue signal to a video signal and the like, and more specifically, variable-length encoding a video signal such as program material transmission, When the variable-length encoded data is fixed-length encoded, the stuff bytes (synchronization adjustment code inserted for byte alignment of synchronization words) are controlled as much as possible to control characters, net queue signals, etc. The present invention relates to a packet-type data multiplexing transmission method and apparatus for effectively superimposing external data.
[0002]
[Prior art]
Currently, signals transmitted from broadcasting stations include signals obtained by multiplexing information signals such as character signals and net cue signals in addition to video signals and audio signals from cameras and the like. The character signal is transmitted by superimposing the character data generated by the character generator on the vertical blanking (vertical blanking interval) of the video signal. The net cue signal is a timing for sending only the main part of a commercial program to the affiliated stations nationwide from the key station using the micronet, and replacing it with the CM of the receiving station immediately before the CM (Commercial Message) is inserted. This information signal is effective in a semi-net in which a CM of a local sponsor is inserted at each receiving station, and is particularly effective for insertion of a CM in a live broadcast program. This information signal is inserted in the vertical blanking period of the video signal in the same manner as the character signal.
[0003]
On the other hand, in recent years, digitalization of broadcasting equipment has been progressing rapidly, and it is becoming more common to compress and transmit images and video materials such as programs or CMs. Under such a technical environment, these materials and programs are compressed and transmitted, and MPEG (Moving Picture Experts Group) 2 standard (ISO / IEC (International Organization for Standardization / International Electrotechnical Commission)) A digital processing system compliant with the International Electrotechnical Commission (13818-1-3) is becoming the standard for transmission systems. Incidentally, a high-efficiency compression method for moving images is called MPEG, and there are compression methods such as MPEG1, MPEG2, and MPEG4. MPEG1 can reproduce video at 1.5 Mbit / s, and MPEG2 can reproduce video at about 10 to 100 Mbit / s.
[0004]
However, in an image encoding technique such as MPEG2, when a video signal is encoded, it may be encoded so as not to include vertical blanking from the viewpoint of redundancy reduction. Therefore, even if a video signal in which a character signal or the like is superimposed on vertical blanking before the above encoding process is created and this video signal is input to the encoder and encoded, There is a drawback that the signal or the like is transmitted without being encoded, and the character signal or the like is lost.
[0005]
Therefore, conventionally, when an information signal such as a character signal or a net cue signal is sent at the same time as video data or audio signal encoded data, in addition to the encoded image data or audio data, a character signal or network signal is transmitted. External data obtained by converting the information signal such as a cue signal is multiplexed and transmitted. As the configuration, for example, there is a TS (transport stream) system of the MPEG2 system shown in FIG. In the figure, one TS packet has a fixed length of 188 bytes. The stream structure is composed of a 4-byte TS header (0x47, etc.), an m-byte AF (adaptation field), and an n-byte PL (payload). The sum (m + n) of AF and PL is 184 bytes. The ratio between the two can be set freely.
[0006]
[Problems to be solved by the invention]
However, the amount of external data such as character signals and net cue signals is smaller than that of image data and audio data. For this purpose, when the fixed length encoding process according to the TS method is performed and transmitted, a payload area (data in the figure) is inserted as shown in FIG. 4A. This area has a very small area, and there is a problem that most of the latter has to multiplex useless stuff bytes. The stuff byte is a code for synchronization adjustment inserted for byte alignment of the synchronization word of the TS packet. In particular, when low-speed data of 64 kbps or less input between video 1 fields is transmitted, a phenomenon that deteriorates transmission efficiency due to multiplexing of useless stuff bytes becomes remarkable.
[0007]
The present invention has been made in view of the above problems, and a packet-based data multiplex transmission method capable of reducing stuff bytes as much as possible when transmitting by fixed-length encoding processing and improving transmission efficiency, and its The object is to provide an apparatus.
[0008]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems, and the invention of claim 1 is directed to image data or audio data obtained by encoding a video signal or an image signal and an audio signal such as program material, In a data multiplexing transmission method for multiplexing and transmitting a video signal or predetermined information synchronized with an image signal,
The video signal or the predetermined information that is synchronized with the image signal is converted into binary data by the binarization process sends the predetermined information in chronological order, it sends the predetermined information and the next binarized data transmitted previously When the information amount with the predetermined information of the binarized data is added, the added information amount is compared with a predetermined threshold value, and when the added information amount is an information amount smaller than the predetermined threshold value, A data multiplexing transmission method characterized in that one packet is generated using the previous predetermined information and the next predetermined information as one information, and is multiplexed and transmitted together with the image data and audio data packets.
[0009]
According to the first aspect of the present invention, when a video signal such as program material or an image signal and an audio signal are encoded, and predetermined information synchronized with the video signal or the image signal is multiplexed and transmitted as one packet, a character signal is transmitted. The information signal (external data) such as a net queue signal or the like is converted into a predetermined format and the predetermined information is transmitted in time series, and the amount of information between the predetermined information transmitted first and the predetermined information transmitted next is determined. When the added information amount is an information amount smaller than a predetermined threshold, one packet is generated as one piece of information by sandwiching an identification code between the predetermined information sent first and the next predetermined information, This is a data multiplexing transmission method for multiplexing and transmitting together with image data and audio data packets. When the added information amount is larger than the predetermined threshold, the predetermined information for one period and the encoded image data and audio data are multiplexed and transmitted as one packet. According to this data multiplexing transmission method, when the amount of external data is small, the stuff byte area can be reduced, so that the transmission efficiency is improved. The identification code is used as a code indicating that data of two or more cycles is compressed.
[0010]
According to a second aspect of the present invention, in a data multiplexing transmission apparatus for multiplexing a video signal such as program material or an image signal and an audio signal,
Image encoding means for encoding the video signal or image signal;
Voice encoding means for encoding the voice signal;
Binary data conversion means for compressing predetermined information synchronized with the video signal or image signal into binary data;
A plurality of storage means for temporarily holding predetermined information which is the binarized data from the data conversion means;
A data amount calculating means for calculating a sum of data amounts of predetermined information held in the plurality of storage means;
Data creation for creating, as one piece of information , predetermined information of the plurality of binarized data held in the plurality of storage means when the total amount of data of the predetermined information held in the plurality of storage means does not exceed a predetermined threshold Means,
A data multiplexing transmission apparatus comprising:
[0011]
In the second aspect of the invention, the video signal or the image signal is encoded by the image encoding means, the audio signal is encoded by the audio encoding means, and an information signal (external data) such as a character signal or a net cue signal is obtained. Is converted into a predetermined format by the data conversion means, the predetermined information from the data conversion means is temporarily held in a plurality of storage means, and the sum of the data amounts of the predetermined information held in the plurality of storage means is a data amount calculation means If the sum of the data amounts of the predetermined information held in the plurality of storage means does not exceed a predetermined threshold, the data creation means processes the identification code between the predetermined information held in the plurality of storage means. Thus, the data multiplexing transmission apparatus generates one packet and multiplexes and transmits the packet together with the image data and audio data packets.
[0012]
Further, in the present invention, the data creation means includes a first switching means for switching an input terminal so that an identification code from an identification code generator is sandwiched between predetermined information from the plurality of storage means, and the first switching means. a temporary storage means for temporarily holding the data, ing and a second switching means for switching the input to multiplex the predetermined information held in the data or the plurality storage means of said temporary storage means.
[0013]
In the present invention, the data creation means is composed of a first switching means, a temporary storage means, and a second switching means, and the first data generation means determines whether the data amount added by the data amount calculation means exceeds a predetermined threshold value. And the second switching means are controlled so that the identification code from the identification code generator is sandwiched between the predetermined information, or the data temporarily stored in the plurality of storage means is not sandwiched between the identification codes. This is a data multiplexing transmission device that generates one packet by outputting every cycle, and multiplexes and transmits the packet together with a packet of image data and audio data. For example, when the data amount added by the data amount calculation means does not exceed a predetermined threshold value, the input terminal of the second switching means is the temporary storage means side, and the predetermined information from the plurality of storage means is passed through the first switching means. The temporary storage means temporarily holds the input, the input terminal of the first switching means is switched, and the identification code from the identification code generator is temporarily held in the temporary storage means via the first switching means. Subsequently, the input terminal is switched to the first switching means, and the predetermined information from the plurality of storage means is temporarily held in the temporary storage means via the first switching means. By controlling the first and second switching means in this way, data in which an identification code is sandwiched between predetermined information is created in the temporary storage means, and an identification code is sandwiched between image data, audio data, and predetermined information. Multiple data can be multiplexed by inputting the data to the multiplexer. If the total amount of data temporarily stored in the plurality of storage means exceeds a predetermined threshold, the data temporarily stored in the plurality of storage means is switched between the first and second switching means every cycle. To the multiplexer.
[0014]
Further, according to the present invention, the data creating means includes data in which an identification code is sandwiched between predetermined information from the plurality of storage means depending on whether or not the data amount added by the data amount calculating means exceeds a predetermined threshold. Ru means der to be converted to.
[0015]
In the present invention, when the data amount added by the data amount calculation means does not exceed a predetermined threshold, the data creation means is means for converting the data so that an identification code is sandwiched between the predetermined information. Further, when the threshold of the data amount held in the plurality of storage means exceeds the predetermined threshold, the predetermined information from the plurality of storage means is sent to the multiplexer every period and multiplexed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a data multiplex transmission method and apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, which is constituted by a digital processing system compliant with the MPEG2 standard.
[0017]
The data multiplex transmission apparatus according to the present embodiment will be described with reference to FIG. 1. An image encoding unit 101 that performs variable-length encoding on video data, and fixed-length encoding (such as PCM) or variable-length encoding on audio data. Speech encoding unit 102, converter 103 that compresses external data when necessary and converts it into a predetermined format, and first order that holds external data (predetermined information) converted into a predetermined format in time series Register 105 and second register 106, third register 109 that temporarily stores and combines external data and identification code during data compression, and the amount of external data temporarily stored in first register 105 and second register 106 A data amount calculation unit 104 that calculates ID, an identification code generator 107 that outputs an identification code, and input terminals 1 and 2 to switch external data that has been compressed. The first switch 108 that selects the identification code and the second and second switches 110 that select data from the second register 106 or the third register 109 by switching the input terminals 1 and 2 from the image encoding unit 101 Multiplexing that multiplexes the image data (image ES), the audio data (audio ES) from the audio encoding unit 102, and the data from the second switch 110, inserts the data into one packet, and sends it out The device 111 is configured. Note that the first switch 108 and the second switch 110 are switched based on the data amount added by the data amount calculation unit 104.
[0018]
The video data is input to the image encoding unit 101, and, for example, in accordance with ISO / IEC13818-3, information having high spatial and temporal correlation is inspected and converted to data with low redundancy. That is, a variable-length encoding process is performed and output as an image ES (elementary stream). The audio data is input to the audio encoding unit 102, subjected to data compression processing using human auditory characteristics so as to comply with, for example, ISO / IEC13818-2, and output as audio ES (elementary stream). . The image ES and audio ES are input to the multiplexer 111.
[0019]
External data is information signals such as text super, subtitles, net cue signals, etc., and as described above, the amount of data is smaller than that of image ES and audio ES, so unnecessary stuff bytes are multiplexed in only one cycle. Must. Therefore, external data is sequentially transferred to the first register 105 and the second register 106 and temporarily stored therein, and the data amount of the first register 105 and the second register 106 is calculated by the data amount calculator 104 and calculated. To do. Then, the data amount calculator 104 always calculates the external data amount for two cycles, and when the sum total is 180 bytes or less, the two amounts are combined into one TS packet. When the sum is 180 bytes or more, the sum is output to the multiplexer 111 for each cycle, and the multiplexing process is performed.
[0020]
The external data compression processing in the embodiment of FIG. 1 will be described below with reference to the flowchart of FIG. This compression processing is composed of a first switch 108, a second switch 110, a third register, an identification code generator 107, and a means for switching control of the first switch 108 and the second switch 110. It is executed by the data creation means.
[0021]
First, external data is input to the converter 103, and compression processing such as binarization processing is performed. The compressed external data is transferred to the first register 105 and temporarily stored. The stored data is sequentially transferred to the second register 106 in accordance with a basic clock (not shown). New data is sequentially input to the first register 105 after data transfer. Thus, the data amount A is stored in the first register 105, and the data amount B is stored in the second register. Both registers always store and hold data amounts for two adjacent periods (step S101). The data amount calculator 104 calculates the sum (A + B) of the data amount of the data stored and held here for two cycles (step S102).
[0022]
As a result of calculation by the data amount calculator 104, if the total amount of data for two cycles is 180 bytes or less, assuming that normal packet processing (multiplexing processing) is performed, both TS packets for two cycles are processed. The stuff bytes will be multiplexed in vain. Conversely, if the total amount of data for two cycles exceeds 180 bytes, TS packets in which useless stuff bytes are multiplexed can be suppressed within one cycle. That is, according to the present invention, it is possible to prevent TS packets from being output in a state where the transmission efficiency is continuously lowered for two or more cycles.
[0023]
Following step S102, the process proceeds to step S103. In step S103, calculation processing of A + B ≦ 180 is performed. If the total amount of data for two cycles is equal to or less than a predetermined threshold (for example, 180 bytes), the process proceeds to Y. First, when the sum (A + B) of the data amount for two cycles is 180 bytes or less (Y), the input end of the first switch 108 is set to 1 side, and the input end of the second switch 110 is set to 2 side, respectively. Switching (step S104). As a result, the data A in the second register 106 is transferred to the third register 109 and temporarily stored.
[0024]
Then, the 2nd switch 110 switches the input terminal of the 1st switch 108 to the 2 side as it is (step S105). Thereby, the identification code output from the identification code generator 107 is transferred to the third register 109 (step S106), and the previously transferred data A is concatenated with the identification code. Thereafter, the input terminal of the first switch 108 is returned to the 1 side (step S107), and the next data B in the second register 106 is transferred to the third register 109. As a result, as shown in FIG. 4B, the third register 109 stores the data A and B for two periods in one TS packet with the identification code in between (step S108). After step S108 is completed, the process returns to step S101.
[0025]
Since the data A and B for two cycles remain in the third register 109 and are not output by the switching operation as described above, the TS packet for the image ES or audio ES is sent from the data amount calculator 104 to the multiplexer 111. A control signal is sent to generate As a result, TS packets transmitted from the multiplexer 111 contain TS packets containing useless stuff bytes, and as a result, transmission efficiency is improved.
[0026]
On the other hand, if the total sum of data for two cycles exceeds 180 bytes (N), the process proceeds to step S109. In this case, since TS packets including useless stuff bytes can be limited to one, there is no problem even if control is performed so as to generate TS packets as usual. Accordingly, the input end of the first switch 108 is fixed to 1 side, and the input side of the second switch 110 is fixed to 1 (step S109), and the conventional ones as shown in FIGS. 4C and 4D are used. Two TS packets 2 and 3 are generated for external data having the same two cycles (steps S110 and S111). After step S111 is completed, the process returns to step S101 and the above steps are repeated.
[0027]
Note that the multiplexer 111 receives the ITU / T recommendation H.264 from the image ES, audio ES, and external data. 222.0 A TS (Transport Stream) packet defined by ISO / IEC13818-1 (MPEG-2 System) is generated. As described above, the TS packet has a fixed length of 188 bytes, and its configuration is composed of a 4-byte TS header (0x47, etc.), AF (adaptation field), and PL (payload) as shown in FIG. Has been. If AF and PL are 184 bytes excluding the header 4 bytes, the ratio of both is free. In many cases, AF is used for PCR (program clock reference) and stuffing. The PL sends a PES packet, PSI (Program Specific Information), external data, and the like. Also, multiplexing with a NULL packet (0xFF) is also performed as needed according to the amount of data stored in the buffer inside the multiplexer 111.
[0028]
There are several other embodiments of the present invention. For example, FIG. 5 illustrates another embodiment of the present invention. In the present embodiment, the first register 105 and the second register 106 are prepared on the input side of the converter 103, and the data amount for calculating the data amount temporarily stored and held in the first register 105 and the second register 106 A calculator 104 is provided. The data amount calculator 104 is temporarily stored and held in the first register 105 and the second register 106, and the data amount is calculated by arithmetic processing. If it is expected to be 180 bytes or less after conversion to a predetermined format (with compression if necessary) based on the calculation result of the data amount, identification of each cycle is performed within the converter 103. Thus, the data conversion is performed with the identification code interposed therebetween, and the converted data is input to the multiplexer 111 together with the image ES and the audio ES, and the multiplexing process is performed to send out TS packets.
[0029]
1 and 5, the first and second registers 105 and 106 are used as data storage means. However, the present invention is not limited to this embodiment, and the same amount of data can be handled. Obviously, possible FIFO (First In First Out) memory may be used.
[0030]
In addition, since video data, audio data, and external data have different time for encoding processing and the like, synchronization of these data becomes a problem. However, these data may be delayed by a delay memory (not shown) or a PTS (presentation time stamp). The timings of the data can be matched. Therefore, even when there is such a difference in processing time, the video signal can be normally reproduced on the decoder (decoder) side.
[0031]
As described above, in the present embodiment, the data processing in which the external data for two cycles is combined into one TS packet has been described. However, in order to further reduce the stuff bytes, the data for three cycles is further converted into one TS packet. It is also possible to summarize. Such a device can be configured, for example, by using three two registers in front of the first switch 108 in FIG. In this apparatus, similarly to the method of the above embodiment, the process of sandwiching the identification code between the data may be repeated twice.
[0032]
Furthermore, in the present embodiment, although not shown in the figure, in order to detect transmission errors in data, Reed-Solomon or CRC (Cyclic Redundancy Check) codes may be used as necessary for each line of image ES, audio ES, and external data. Obviously, it may be added to the multiplexer.
[0033]
Of course, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the scope of the present invention.
[0034]
【The invention's effect】
As described above, according to the present invention, when external data such as a character signal or a net cue signal is multiplexed and transmitted to a video signal or the like, more data is limited without reducing transmission efficiency. There is an advantage that it can be transmitted on a transmission line, and as a result, it is possible to provide an extremely effective data multiplexing transmission method and apparatus that contributes to a reduction in transmission cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a data multiplexing transmission apparatus according to the present invention.
FIG. 2 is a flowchart for explaining a data multiplexing transmission method in a data multiplexing transmission apparatus according to the present invention.
FIG. 3 is a diagram showing a format of a TS packet of the data multiplexing transmission apparatus according to the present invention.
4A shows the format of a conventional TS packet, FIG. 4B shows the structure of a TS packet when data for two periods is compressed to improve transmission efficiency, and FIGS. d) shows the structure of a TS packet transmitted in correspondence with each period when the sum of data for two periods exceeds 180 bytes.
FIG. 5 is a block diagram showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 Image encoding part 102 Audio | voice encoding part 103 Conversion part 104 Data amount calculation part 105 1st register 106 2nd register 107 Identification code generator 108 1st switch 109 Third register 110 2nd switch 111 Multiplexer

Claims (2)

In a data multiplexing transmission method for multiplexing and transmitting image data or audio data obtained by encoding a video signal or image signal and audio signal such as program material, and predetermined information synchronized with the video signal or image signal,
The video signal or the predetermined information that is synchronized with the image signal is converted into binary data by the binarization process sends the predetermined information in chronological order, it sends the predetermined information and the next binarized data transmitted previously When the information amount with the predetermined information of the binarized data is added, the added information amount is compared with a predetermined threshold value, and when the added information amount is an information amount smaller than the predetermined threshold value, A data multiplexing transmission method characterized in that one packet is generated using the previous predetermined information and the next predetermined information as one information, and is multiplexed and transmitted together with the image data and audio data packets. In a data multiplexing transmission device that multiplexes video signals such as program materials or image signals and audio signals,
Image encoding means for encoding the video signal or image signal;
Voice encoding means for encoding the voice signal;
Binary data conversion means for compressing predetermined information synchronized with the video signal or image signal into binary data;
A plurality of storage means for temporarily holding predetermined information which is the binarized data from the data conversion means;
A data amount calculating means for calculating a sum of data amounts of predetermined information held in the plurality of storage means;
Data creation for creating, as one piece of information , predetermined information of the plurality of binarized data held in the plurality of storage means when the total amount of data of the predetermined information held in the plurality of storage means does not exceed a predetermined threshold Means,
A data multiplexing transmission apparatus comprising:

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