JP2000134169A - Stream transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an MPEG-TS transmitter in which a value of a PID/ continuity counter of a TS packet belonging to a multiplexed transport stream is rewritten at a high-speed, resulting in transmitting the multiplexed stream at a higher speed when transmitting the multiplexed transport stream. SOLUTION: A PID/CC rewrite control section 107 rewrites the value of a PID/continuity counter included in a TS packet when a DMA transfer, where a TS packet is read from a data buffer section 102 and written directly to a transmission buffer section 105. In this case, since the number of times of data read from and write of data to a memory is less than the case when accessing is made to the transmission buffer section 105 or the like for rewriting data, a time required for rewrite processing can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stream transmitting apparatus, and more particularly to an MPEG-TS transmitting apparatus for multiplexing and transmitting a transport stream (MPEG-TS) used in the MPEG system.

[0002]

2. Description of the Related Art In the MPEG system employed in CS (communication satellite) broadcasting and the like, each transport stream is divided into TS packets and time-division multiplexed, thereby using one frequency band (channel). Transmission of a plurality of transport streams (programs) is performed. A stream obtained by multiplexing a plurality of transport streams is called a multiplexed stream. T
The S packet includes a PID (Packet) indicating to which transport stream the TS packet belongs.
(Identifier). On the receiving side,
By extracting TS packets belonging to each transport stream by referring to the PID, each transport stream is reproduced from the transmitted multiplexed stream. The TS packet also includes a continuity value such that integer values from 0 to 15 are sequentially (and circulated) for each transport stream.
A counter is provided. The receiving side detects whether or not the TS packet with the same PID is discarded during transmission, based on the continuity of the continuity counter. The MPEG, transport stream, PID, continuity counter, and the like are described in detail in, for example, "Latest MPEG Textbook" (edited by Hiroshi Fujiwara, ASCII Publishing Bureau, 1994).

[0003] The value of the PID is rewritten when a transport stream is transmitted. This is because, for example, in CS broadcasting, each program is repeatedly broadcast while changing the combination of programs arbitrarily on one channel. Therefore, it is necessary to change the value of the PID included in the TS packet belonging to each transport stream every broadcast. Because there is. The value of the continuity counter is rewritten as needed when the transport stream is transmitted. Rewriting is performed, for example, when performing jump reproduction or high-speed reproduction by dropping frames. This is because the value of the continuity counter becomes discontinuous when jump reproduction or high-speed reproduction is performed, and it is necessary to change the value to be continuous.

FIG. 6 is a block diagram showing an example of the configuration of a conventional transport stream transmitting apparatus. FIG.
Is provided in, for example, a CS broadcasting station, and multiplexes a plurality of transport streams and transmits the multiplexed streams toward a receiver. In FIG. 6, the conventional M
The PEG-TS transmission device includes a data storage unit 601, a data buffer unit 602, a data read control unit 603.
Multiplex transmission section 604, transmission buffer section 605, D
An MA transfer control unit 606 and a PID / continuity counter rewrite control unit (hereinafter referred to as a PID / CC rewrite control unit 607) 607 are provided. PID
The / CC rewrite control unit 607 is provided in association with the transmission buffer unit.

[0005] The data storage unit 601 stores a plurality of transport streams. Data buffer unit 602
Temporarily stores (buffers) data of a plurality of transport streams to be transmitted. The data read control unit 603 controls a process of reading data from the data storage unit 601. The multiplex transmission unit 604
The plurality of streams stored in the data storage unit 601 are divided into packets and multiplexed, and transmitted as one multiplexed stream. The transmission buffer unit 605 temporarily stores input data to the multiplex transmission unit 604. DMA
The transfer control unit 606 controls a DMA transfer process of data from the data buffer unit 602 to the transmission buffer unit 605. The PID / CC rewrite control unit 607 accesses the transmission buffer unit 605 and stores the TS stored therein.
It controls the rewriting process for rewriting the value of the PID / continuity counter included in the packet.

[0006] The operation of the conventional MPEG-TS transmitting apparatus configured as described above will be described below. The data storage unit 601 stores a plurality of transport streams. In the case of CS broadcasting, several tens to hundreds of programs are simultaneously broadcast per channel, so that the data storage unit 601 stores, for example, several tens to hundreds of transport streams. When the operator instructs start of transmission, the data read control unit 603 reads the data of the plurality of transport streams from the data storage unit 601 and reads the data of the plurality of transport streams.
Write to 02.

Next, the DMA transfer control unit 606 reads the data of each transport stream from the data buffer unit 602 in TS packet units, and writes it directly to the transmission buffer unit 605. As a result of the DMA transfer processing, data of a plurality of transport streams to be transmitted (hereinafter, transmission data) is stored in the transmission buffer.

Next, a PID / CC rewrite control unit 607
Reads out the transmission data from the transmission buffer unit 605 and rewrites the value of the PID included in each TS packet. If the value of the continuity counter included in the TS packet belonging to the transport stream becomes discontinuous due to, for example, jump reproduction of a certain transport stream, the PID / CC rewrite control unit 607 Rewrites the value so as to be continuous in addition to the rewriting of the PID.

The PID / CC rewrite control unit 60
7 writes the transmission data after rewriting the value of the PID / continuity counter into the transmission buffer unit 605. That is, in the transmission buffer unit 605, the transmission data before rewriting is overwritten by the transmission data after rewriting the value of the PID / continuity counter. The transmission data (after rewriting the value of the PID / continuity counter) stored in the transmission buffer is input to the multiplex transmission unit 604. The multiplex transmission unit 604 multiplexes the input transmission data and transmits the multiplexed stream to the receiver as a multiplexed stream. In the above description, the PID / CC rewrite control unit 607 accesses the transmission buffer unit 605 to rewrite the value of the PID / continuity counter included in the TS packet, but accesses the data buffer unit 602. A similar rewriting process may be performed.

[0010]

By the way, MPEG-
The TS transmission device is required to increase the transmission speed of the multiplexed stream for the purpose of increasing the number of programs and improving the image quality. In order to increase the transmission speed, it is necessary to increase the processing speed of the rewriting process for rewriting the value of the PID / continuity counter included in the TS packet. However, if the rewriting process is performed by accessing the transmission buffer unit 605 as described above, it takes time to read data from the transmission buffer unit 605 and write data to the transmission buffer unit 605. Also have limitations. As a result, the conventional MPEG-TS transmission device could not increase the transmission speed of the multiplexed stream much.

In a conventional MPEG-TS transmitting apparatus, control information for performing a rewriting process for rewriting a value of a PID / continuity counter is stored in, for example, a control information storage unit (not shown). The processing is performed with reference to the control information. However, if the rewriting process is performed while referring to the control information in the control information storage unit or the like, it takes a long time to read the control information. As a result, the conventional MPEG-TS transmission device could not increase the transmission speed of the multiplexed stream much.

Therefore, an object of the present invention is to rapidly rewrite the value of the PID / continuity counter of a TS packet belonging to a transport stream when multiplexing and transmitting the transport stream. Accordingly, it is an object of the present invention to provide an MPEG-TS transmitting apparatus capable of transmitting a multiplexed stream at a higher speed.

[0013]

Means for Solving the Problems and Effects of the Invention A first invention is a stream transmitting apparatus for multiplexing and transmitting a stream, wherein a storage means for storing a plurality of streams,
Multiplexing means for dividing a plurality of streams accumulated in the accumulating means into packet units, multiplexing them, and sending them out as one multiplexed stream, is provided along with the accumulating means, and temporarily stores output data from the accumulating means. A second buffer for temporarily storing input data to the multiplex transmission means, and a second buffer for temporarily storing input data to the multiplex transmission means;
DMA transfer control means for controlling a DMA transfer processing for directly transferring data to the buffer means, and a DMA transfer control means for reading data from the first buffer means by the DMA transfer processing. Rewriting control means is provided for controlling rewriting processing for rewriting control data contained in a packet to be written into the buffer means.

In the first invention, the control data contained in the packet read from the first buffer means and written to the second buffer means by DMA transfer is rewritten. As compared with the case where the control data is rewritten by accessing the means or the second buffer means, the number of times of reading data from the memory / writing data to the memory can be reduced. Therefore, the time required for rewriting the control data can be reduced.
As a result, the transmission speed of the multiplexed stream can be further increased.

A second aspect of the present invention is a stream transmitting apparatus for multiplexing and transmitting a stream, wherein the storing means stores a plurality of streams, and the plurality of streams stored in the storing means are divided into packet units and multiplexed. A multiplex transmission means for transmitting as one multiplexed stream, a conversion means for converting the format of input data to the storage means, and a conversion means for converting the format of input data to the storage means; First buffer means for temporarily storing output data from the multiplex transmission means, second buffer means for temporarily storing input data to the multiplex transmission means, and a first buffer means. DMA transfer control means for controlling DMA transfer processing for directly transferring data from the buffer means to the second buffer means,
The conversion means converts the format of the input data to the storage means so as to be suitable for the DMA transfer processing.

According to the second aspect, the time required for DMA transfer can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

According to a third aspect of the present invention, there is provided a stream transmitting apparatus for multiplexing and transmitting a stream, comprising: a storage unit for storing a plurality of streams; A multiplex transmission means for transmitting as one multiplexed stream, a conversion means for converting the format of input data to the storage means, and a conversion means for converting the format of input data to the storage means; First buffer means for temporarily storing output data from the multiplex transmission means, second buffer means for temporarily storing input data to the multiplex transmission means, and a first buffer means. DMA for directly transferring data from the means to the second buffer means
DMA transfer control means for controlling transfer processing, and DMA
A rewrite which is provided in association with the transfer control means and controls rewrite processing for rewriting control data included in a packet which is read from the first buffer means by the DMA transfer processing and is to be written to the second buffer means. Control means is provided, wherein the conversion means converts the format of the input data to the storage means so as to be suitable for the DMA transfer processing, and adds control information necessary for the rewriting processing to the input data.

According to the third aspect, the time required for DMA transfer can be reduced. Also, when storing a stream in the data storage means, control information is added to the stream itself, and the DMA transfer process and the process of rewriting the control data are performed with reference to the control information. Compared with storing the information in the control information storage unit or the like and performing the same processing with reference to the information, the time and effort for reading out the control information can be reduced, and thus the time required for the processing for rewriting the control data can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

A fourth invention is an MPE for multiplexing and transmitting a transport stream used in the MPEG system.
A G-TS transmission device, comprising: storage means for storing a plurality of transport streams; and a plurality of transport streams stored in the storage means, each of which is divided into TS packets and multiplexed to form one multiplexed stream. A first buffer means for temporarily storing output data from the storage means, a first buffer means for temporarily storing output data from the storage means, and a multiplex transmission means provided for the multiplex transmission means. Buffer means for temporarily storing input data of
DMA transfer control means for controlling a DMA transfer processing for directly transferring data to the buffer means, and a DMA transfer control means for reading data from the first buffer means by the DMA transfer processing. PI included in the TS packet to be written to the buffer means
Rewriting control means is provided for controlling rewriting processing for rewriting the value of D (packet identifier) / continuity counter.

According to the fourth aspect of the present invention, the P packet included in the TS packet to be read from the first buffer means by the DMA transfer and to be written to the second buffer means.
Since the value of the ID / continuity counter is rewritten, data reading / reading from the memory is performed in comparison with the case where the value of the PID / continuity counter is rewritten by accessing the first buffer means or the second buffer means, for example. The number of times of writing data to the memory is small. Therefore, the time required for rewriting the value of the PID / continuity counter can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

In a fifth aspect based on the fourth aspect, the rewrite control means, when each value of the continuity counter of the two consecutive TS packets becomes discontinuous, It is characterized in that each value is made continuous by inserting a dummy TS packet between them.

According to the fifth aspect of the invention, when the values of the continuity counter of two consecutive TS packets become discontinuous, the respective values can be made continuous without rewriting. Thus, the process of rewriting the value of the continuity counter is reduced, and the time required for the rewriting process can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

A sixth invention is an MPE for multiplexing and transmitting a transport stream used in the MPEG system.
A G-TS transmission device, comprising: storage means for storing a plurality of transport streams; and a plurality of transport streams stored in the storage means, each of which is divided into TS packets and multiplexed to form one multiplexed stream. Multiplexing means for transmitting the data as data, a conversion means for converting the format of the input data to the storage means, a conversion means for converting the format of input data to the storage means, and a storage means for temporarily storing output data from the storage means. A first buffer means, a second buffer means for temporarily storing input data to the multiplex transmission means, and a second buffer means for temporarily storing input data to the multiplex transmission means. DMA transfer control means for controlling DMA transfer processing for transferring data directly to the means,
It is characterized in that the format of the input data to the storage means is converted so as to be suitable for the transfer processing.

According to the sixth aspect, the time required for DMA transfer can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

According to a seventh aspect, in the sixth aspect, the DM is provided.
A PID (packet identifier) / continuity included in a TS packet which is provided in association with the A transfer control means and which is to be read from the first buffer means by the DMA transfer processing and to be written to the second buffer means Tee
It further comprises rewriting control means for controlling rewriting processing for rewriting the value of the counter, and the conversion means further adds control information necessary for the rewriting processing to the input data to the storage means.

In the seventh aspect, the P packet included in the TS packet read from the first buffer means by the DMA transfer and about to be written to the second buffer means is used.
Since the value of the ID / continuity counter is rewritten, data reading / reading from the memory is performed in comparison with the case where the value of the PID / continuity counter is rewritten by accessing the first buffer means or the second buffer means, for example. The number of times of writing data to the memory is small. Therefore, the time required for rewriting the value of the PID / continuity counter can be reduced. When storing the transport stream in the data storage means, control information is added to the transport stream itself, and the DMA transfer process and the process of rewriting the PID / continuity counter are performed by the control information. Therefore, for example, as compared with a case where control information is stored in a control information storage unit or the like and a similar process is performed by referring to the control information, the time and effort for reading the control information can be reduced.
The time required for rewriting the value of the ID / continuity counter can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

According to an eighth aspect, in the seventh aspect, the control information includes information indicating a head position of the GOP.

According to a ninth aspect, in the seventh aspect, the control information includes information indicating a head position of the I frame.

According to the eighth or ninth aspect, it is easy to deal with jump reproduction, high-speed reproduction, and the like.

[0030] In a tenth aspect based on the seventh aspect, the rewrite control means, when each value of the continuity counter of the two consecutive TS packets becomes discontinuous, sets the two TS packets to the same value. It is characterized in that each value is made continuous by inserting a dummy TS packet between them.

In the tenth aspect, the two consecutive
When each value of the continuity counter of one TS packet becomes discontinuous, each value can be made continuous without rewriting, so that the process of rewriting the value of the continuity counter is reduced. Thus, the time required for the rewriting process can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

In an eleventh aspect based on the seventh aspect, the conversion means is arranged so that the value of the continuity counter of the TS packet including the head position of the GOP or the head position of the I frame becomes zero. Start position or I
It is characterized in that a dummy TS packet is inserted immediately before a TS packet including the head position of a frame.

According to the eleventh aspect, it is easy to deal with jump reproduction, high-speed reproduction, and the like.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration of an MPEG-TS transmitting apparatus according to a first embodiment of the present invention. The MPEG-TS transmission device shown in FIG.
The S broadcast station is provided together with a video server (not shown) that stores video / audio data (transport stream) of a program. Then, a plurality of transport streams are obtained from the video server and multiplexed, and the obtained multiplexed stream is transmitted to the receiver side.

In FIG. 1, the MP according to the first embodiment
The EG-TS transmission device includes a data storage unit 101, a data buffer unit 102, a data read control unit 103,
Multiplex transmission unit 104, transmission buffer unit 105, DMA
It includes a transfer control unit 106 and a PID / continuity counter rewrite control unit (hereinafter referred to as a PID / CC rewrite control unit 107). The PID / CC rewrite control unit 107 is provided in association with the DMA transfer control unit 106.

The data storage unit 101 is constituted by a hard disk, for example, and stores a plurality of transport streams. The data buffer unit 102 is composed of, for example, a RAM, and temporarily stores (buffers) output data from the data storage unit. Data read control unit 103
Controls the process of reading data from the data storage unit 101. The multiplex transmission unit 104 divides a plurality of streams stored in the data storage unit 101 into packet units and multiplexes them, and transmits them as one multiplexed stream. The transmission buffer unit 105 is composed of, for example, a RAM, and temporarily stores input data to the multiplex transmission unit 104.
The DMA transfer control unit 106 controls a DMA transfer process of data from the data buffer unit 102 to the transmission buffer unit 105. The PID / CC rewrite control unit 107
The PID / continuity information included in the TS packet to be read from the data buffer unit 102 and written to the transmission buffer unit 105 by the A transfer process
The rewriting process for rewriting the value of the counter is controlled.

The two buffer units, the data buffer unit 102 and the transmission buffer unit 105, are provided to ensure continuity of a transport stream including video data. In addition, these data buffer units 102
The data transfer between the transmission buffer unit 105 and the transmission buffer unit 105 is performed by a DMA transfer method in order to reduce the load on a CPU (not shown).

The following describes the MPE constructed as described above.
The operation of the G-TS transmission device will be described. Data storage unit 10
1 stores video / audio data of a plurality of programs to be broadcast obtained from a video server, that is, a plurality of transport streams to be transmitted. In the case of CS broadcasting, several tens to hundreds of programs are simultaneously broadcast per channel, so that several tens to hundreds of transport streams are stored in the data storage unit 101, for example. When the operator instructs the start of transmission, the data read control unit 103 stores the data of the plurality of transport streams in the data storage unit 1.
01 and written to the data buffer unit 102.

Next, the DMA transfer control unit 106 reads the data of each transport stream from the data buffer unit 102 in units of TS packets or in units of blocks composed of a plurality of TS packets, and writes the data directly to the transmission buffer unit 105. . As a result of the DMA transfer processing, the transmission buffer unit 105 stores data of a plurality of transport streams to be transmitted (hereinafter, transmission data).

In the above DMA transfer processing, PID / C
The C rewrite control unit 107 rewrites the value of the PID included in the TS packet belonging to each transport stream. If the value of the continuity counter included in the TS packet belonging to the transport stream becomes discontinuous due to, for example, jump reproduction of a certain transport stream, the PID / C
The C rewrite control unit 107 rewrites the value so as to be continuous with the rewrite of the PID.

That is, the data buffer unit 102
A process of rewriting the value of the PID included in the TS packet is performed until the packet is read and written to the transmission buffer unit 105. Further, when the values of the continuity counters of two consecutive TS packets become discontinuous, a process of rewriting the values so as to be continuous is also performed. Since the position of the PID / continuity counter in the TS packet is determined in advance, the above-mentioned PID / continuity counter rewriting process is performed by overwriting only the data at that position with another data. It can be performed.

DMA transfer control unit 106 and PID / C
The C rewrite control unit 107 performs the above-described DMA transfer process and the rewrite process of the accompanying PID / continuity counter with reference to control information stored in a control information storage unit (not shown), for example. . The control information includes the following information. (1) For each transport stream, the number of TS packets, their data length, and their types (such as video packets or audio packets) (2) Positions of random access points (for example, the position of the head of an I frame, The position of the head of the GOP, etc.)

Instead of performing the above-described transfer processing and rewriting processing with reference to control information stored in a control information storage unit (not shown), for example, a transport stream is stored in the data storage unit 101. In this case, control information may be added to the transport stream itself and stored, and the control may be performed with reference to the control information. This saves the trouble of reading the control information from the control information storage unit, and as a result, the time required for the process of rewriting the value of the PID / continuity counter can be reduced (see the second embodiment).

When data is written to the transmission buffer unit 105 by the rewriting process performed in the DMA transfer process, the value of the PID / continuity counter included in the TS packet has already been rewritten. are doing. The transmission data stored in the transmission buffer is input to the multiplex transmission unit 104. Multiplex sending unit 10
4 multiplexes the input transmission data and sends out the multiplexed stream to the receiver side. This transmission processing is performed, for example, by using an ATM (Asynchronous Tra).
nsfer Mode).

As described above, the MPEG-TS shown in FIG.
In the sending device, the value of the PID / continuity counter included in the TS packet is rewritten during the DMA transfer in which the TS packet is read from the data buffer unit 102 and written directly to the transmission buffer unit 105. And the like, the number of times of reading data from the memory / writing data to the memory can be reduced as compared with the related art in which data is accessed and rewritten. Therefore, PID
/ The time required to rewrite the value of the continuity counter can be reduced. As a result, the transmission speed of the multiplexed stream can be further increased.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
It is a block diagram which shows the structure of the MPEG-TS transmission device which concerns on embodiment. The MPEG-TS transmitting apparatus shown in FIG. 2 is provided, for example, in a CS broadcasting station together with a video server (not shown) storing video / audio data (transport stream) of a program, similarly to the apparatus shown in FIG.
Then, a plurality of transport streams are obtained from the video server and multiplexed, and the obtained multiplexed stream is transmitted to the receiver side.

The MPEG-TS transmitting apparatus shown in FIG. 2 is the same as the MPEG-TS transmitting apparatus shown in FIG. Reformat section 2
01 is the data storage unit 101 obtained from the video server.
By adding control information (see the first embodiment) to the transport stream (original data) stored in the original data, the original data is converted into data having a new format.

The other components perform the same operation as that shown in FIG. However, the DMA transfer control unit 106 and P
The ID / CC rewrite control unit 107 performs the DMA transfer process and the rewrite process with reference to the control information added to the transport stream itself (the first stream).
In the embodiment, the processing is performed with reference to the control information stored in the control information storage unit (not shown).

The following describes the MPE configured as described above.
The operation of the G-TS transmission device will be described. MPE shown in FIG.
The operation of the G-TS transmitting apparatus differs from that of the MPEG-TS transmitting apparatus shown in FIG. 1 only in the following two points. The first is that the data is acquired from the video server and stored in the data storage unit 101.
The second point is that the format of each transport stream stored in the transport stream is converted and control information is added to the transport stream itself. The second is the DMA transfer processing and the PID / continuity The process of rewriting the value of the counter is performed with reference to the control information added to the transport stream. Therefore, only these differences will be described in detail, and description of the same operations as those of the MPEG-TS transmitting apparatus shown in FIG. 1 will be omitted.

When the operator specifies programs to be broadcast, a plurality of transport streams corresponding to those programs are transmitted from a video server (not shown) to the data storage unit 1.
01 and stored there. At the time of this transfer processing, the reformatting section 201 converts the format of each transport stream and adds control information to each transport stream.

FIG. 3 is a diagram showing the format of the transport stream before conversion by the reformat unit 201 of FIG. 2 and the format of the transport stream after conversion. In FIG. 3, in the transport stream before conversion, one CPCS-PDU (384 bytes) is composed of two TS packets each having a data length of 188 bytes and a trailer of 8 bytes. In the transport stream before the conversion, the reformatting unit 201 adds 4-byte control information (indicated by hatching in the figure) to the beginning of each CPCS-PDU to form a new CPCS-PDU,
Further, 42 new CPCS-PDUs are grouped as one group, and 88 bytes of control information (shown by oblique lines in the figure) are added to the end of the group.

Therefore, in the transport stream after format conversion, control information (4 bytes), two TS packets (188 bytes), and a trailer (8 bytes)
Constitute one CPCS-PDU (388 bytes), and furthermore, 42 CPCS-PDUs and control information (8
One data block (16384 bytes = 16 Kbytes) is composed of 8 bytes.

FIG. 4 is a diagram showing an example of control information (information indicated by hatching) added to the head of each CPCS-PDU in FIG. In FIG. 4, in the control information, the data length (lower 8 bits) of the CPCS-PDU is stored in the first byte, and the T byte per CPCS-PDU is stored in the second byte.
The number of S packets and the data length of the CPCS-PDU (upper 4 bits) are described in the third byte, the type of the first TS packet, and the fourth byte, the type of the second TS packet. I have.

On the other hand, the control information (indicated by hatching) added to the end of the data block in FIG. 3 includes the position of the random access point (for example, the position of the head of the I frame or the head of the GOP). Position etc.) are described. An example is shown in FIG. According to the control information of FIG. 5, it can be seen that the 11th and 32nd packets are random access points. Since the maximum number of TS packets in one data block is 84, the position of the random access point is 8
It can be completely expressed by 8-byte control information.

A transport stream having a new format as shown in FIG. 3 is stored in the data storage unit 101, for example, about several tens to one hundred. When the operator instructs the start of transmission, the data read control unit 103 reads the data of the plurality of transport streams from the data storage unit 101 and writes the data in the data buffer unit 102.

Next, the DMA transfer control unit 106 reads the data of each transport stream from the data buffer unit 102 in data block units shown in FIG. 3, and writes the data directly to the transmission buffer unit 105. As described above, by performing the DMA transfer in units of 16-Kbyte data blocks, processing related to the DMA transfer is reduced, and the time required for the DMA transfer is reduced. This DM
As a result of the A transfer process, the transmission buffer unit 105 stores data of a plurality of transport streams to be transmitted (hereinafter, transmission data).

At the time of this DMA transfer processing, as in the first embodiment, the PID / CC rewrite control unit 107 rewrites the value of the PID included in the TS packet. If the value of the continuity counter included in the TS packet belonging to the transport stream becomes discontinuous due to, for example, jump reproduction of a certain transport stream, the PID / CC rewrite control unit 1
In step 07, the value is rewritten so as to be continuous with the rewriting of the PID.

DMA transfer control unit 106 and PID / C
The C rewrite control unit 107 performs the above-described DMA transfer process and the process of rewriting the PID / continuity counter accompanying the DMA transfer process with reference to the control information added to the transport stream.

Here, an example of the process of rewriting the value of the continuity counter will be described. When a certain transport stream is jump-reproduced, the continuity counter value becomes discontinuous before and after the jump position. For example, it is assumed that after the transport stream has been reproduced up to a TS packet having a continuity counter value of 13, the jump has been made to a certain position, and the reproduction has been started again therefrom. At this time, the playback resume position is GOP
At the beginning (ie, I frame)
Reproduction is always restarted from a TS packet whose continuity counter value is 0. Therefore, the value of the continuity counter is increased from 13 to 14 and 15
Is skipped and becomes 0 immediately. In this case, the value of the continuity counter can be made continuous by rewriting the value of the continuity counter of the TS packet after the reproduction restart position so as to be sequentially shifted by two.

However, in this embodiment, the value of the continuity counter is not actually rewritten,
By inserting two S packets between the reproduction end position and the reproduction restart position, the value of the continuity counter is made continuous. In the above case, the PID / CC rewrite control unit 107 inserts two dummy TS packets whose continuity counters are 14 and 15 between the reproduction end position and the reproduction restart position.

That is, when the value of the continuity counter included in the TS packet belonging to a certain transport stream becomes discontinuous, the value of the continuity counter of the TS packet at the reproduction end position is set to k ( (k is an arbitrary integer from 0 to 14), and a total of (15−k) dummy TS packets whose continuity counter values are (k + 1) to 15 are generated. Insert between the position. Note that k
Is 15, there is no need to generate a dummy TS packet.

As described above, when the value of the continuity counter becomes discontinuous, a dummy TS packet is generated and inserted between the reproduction end position and the reproduction restart position to make it continuous. Since such a rewriting process is performed, the rewriting process of the value of the continuity counter is reduced, and as a result, the time required for the rewriting can be reduced.

PID performed at the time of this DMA transfer processing
By the time the data is written to the transmission buffer unit 105 by the / continuity counter rewriting process, the value of the PID / continuity counter included in the TS packet has already been rewritten. The transmission data stored in the transmission buffer is input to the multiplex transmission unit. The multiplexing unit multiplexes the input data and transmits the multiplexed stream to the receiver as a multiplexed stream. This transmission processing is performed by, for example, the ATM method.

On the other hand, the following method can be used to eliminate the discontinuity of the continuity counter value when the transport stream is jump-reproduced. That is, for example, in the reformatting unit 201, GO
A dummy TS packet is inserted immediately before the continuity counter of the TS packet at the beginning of P (that is, the I frame) so that the value of the continuity counter becomes 0. For example, GO
If the value of the continuity counter of the TS packet at the beginning of P is 13, the continuity of the (dummy) TS packet immediately before the leading TS packet of the GOP is inserted by inserting two dummy TS packets. The value of the continuity counter of the TS packet at the head of the GOP can be set to 0. As a result, in the case of a jump, after the continuity counter value is transmitted up to 15 TS packets, the value of the continuity counter always continues at the head position of any GOP where the jump destination is. In this way, by inserting a dummy TS packet in advance by the reformatting unit 201 or the like, it is possible to omit the process of rewriting the value of the continuity counter when transmitting the stream.

As described above, the MPEG-TS shown in FIG.
The transmitting device rewrites the value of the PID / continuity counter included in the TS packet during the DMA transfer in which the TS packet is read from the data buffer unit 102 and written directly to the transmission buffer unit 105. The number of times of reading data from the memory / writing data to the memory can be reduced. Therefore, PID
/ The time required for rewriting the value of the continuity counter can be reduced. As a result, the transmission speed of the multiplexed stream can be increased.

When storing the transport stream in the data storage unit 101, control information is added to the transport stream itself, and the DMA transfer process and the process of rewriting the PID / continuity counter are performed. Since the control information is referred to, for example, the control information is stored in a control information storage unit or the like (not shown) and the control information is stored in a control information storage unit or the like as compared with performing the same processing by referring to the control information. Saves the trouble of reading from
The time required for the rewriting process can be reduced. As a result, the transmission speed of the multiplexed stream can be increased.

Further, when the value of the continuity counter becomes discontinuous, a dummy TS packet is generated and inserted between the reproduction end position and the reproduction restart position so as to make it continuous. Since the rewriting process is performed, the process of rewriting the value of the continuity counter is reduced, and the time required for the rewriting process can be reduced. As a result, the transmission speed of the multiplexed stream can be increased.

[Brief description of the drawings]

FIG. 1 shows an MPEG-TS according to a first embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a transmission device.

FIG. 2 shows an MPEG-TS according to a second embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a transmission device.

FIG. 3 shows a format of data (transport stream before conversion) before conversion by a reformatting unit 201 of FIG. 2 and a format of new data (transport stream after conversion) obtained by conversion; FIG.

FIG. 4 is a diagram illustrating an example of control information added to the head of each CPCS-PDU in FIG. 3;

FIG. 5 is a diagram illustrating an example of control information added to the end of the data block in FIG. 3;

FIG. 6 is a block diagram showing an example of a configuration of a conventional transport stream transmitting device.

[Explanation of symbols]

Reference Signs List 101 data storage unit 102 data buffer unit 103 data read control unit 104 multiplex transmission unit 105 transmission buffer unit 106 DMA transfer control unit 107 PID / CC (continuity counter) rewrite control unit 201 reformat unit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 7/081 H04N 7/13 Z 7/24 F term (reference) 5C053 FA23 FA27 GA11 GB23 GB29 KA01 5C059 KK11 MA00 PP05 RB02 RC01 RC24 SS06 UA01 UA32 UA38 5C063 AA01 AB03 AB07 AC01 CA36 CA38 CA40 DA07 DA13 5K028 AA00 BB05 EE03 EE05 KK01 RR03 SS24 5K030 GA01 HB02 JA01 JA05 KA03 KA12

Claims (11)

[Claims] 1. A stream transmitting apparatus for multiplexing and transmitting streams, comprising: a storage unit for storing a plurality of streams; a plurality of streams stored in the storage unit being divided into packets and multiplexed; Multiplex transmission means for transmitting as one multiplexed stream; first buffer means for temporarily storing output data from the storage means; and multiplex transmission means provided for the multiplex transmission means. A second buffer means for temporarily storing input data to the multiplex transmission means; a DM controlling a DMA transfer process for directly transferring data from the first buffer means to the second buffer means.
A transfer control means, provided in association with the DMA transfer control means, included in a packet to be read from the first buffer means by the DMA transfer processing and to be written to the second buffer means A stream sending device comprising a rewriting control means for controlling rewriting processing for rewriting control data to be rewritten. 2. A stream transmitting apparatus for multiplexing and transmitting streams, comprising: a storage unit for storing a plurality of streams; a plurality of streams stored in the storage unit being divided into packets and multiplexed, respectively. Multiplex transmission means for transmitting as one multiplexed stream; conversion means provided in connection with the storage means, for converting the format of input data to the storage means; provided in connection with the storage means; First buffer means for temporarily storing the output data of the second multiplex transmission means, second buffer means for temporarily storing input data to the multiplex transmission means, and the first buffer means. DMA transfer control means for controlling a DMA transfer process for directly transferring data from the buffer means to the second buffer means. The stream transmission device, wherein the conversion unit converts a format of input data to the storage unit so as to be suitable for the DMA transfer process. 3. A stream transmitting apparatus for multiplexing and transmitting streams, comprising: a storage unit for storing a plurality of streams; a plurality of streams each stored in the storage unit being divided into packets and multiplexed; Multiplex transmission means for transmitting as one multiplexed stream; conversion means provided in connection with the storage means, for converting the format of input data to the storage means; provided in connection with the storage means; A first buffer means for temporarily storing output data of the second transmission means; a second buffer means provided in association with the multiplex transmission means for temporarily storing input data to the multiplex transmission means; DM for controlling DMA transfer processing for directly transferring data from the buffer means to the second buffer means
A transfer control means, provided in association with the DMA transfer control means, included in a packet to be read from the first buffer means by the DMA transfer processing and to be written to the second buffer means Rewriting control means for controlling rewriting processing for rewriting control data to be performed, wherein the conversion means converts a format of input data to the storage means so as to be suitable for the DMA transfer processing, and converts the format required for the rewriting processing. A stream sending device, wherein control information is added to the input data. 4. An MPEG-TS transmission apparatus for multiplexing and transmitting a transport stream used in the MPEG system, comprising: storage means for storing a plurality of transport streams; and a plurality of storage streams stored in said storage means. The transport stream is divided into TS packets and multiplexed,
Multiplex transmission means for transmitting as one multiplexed stream; first buffer means provided in association with the storage means for temporarily storing output data from the storage means; provided in association with the multiplex transmission means A second buffer means for temporarily storing input data to the multiplex transmission means, a DM for controlling a DMA transfer process for directly transferring data from the first buffer means to the second buffer means.
A transfer control means, and a TS packet which is provided in association with the DMA transfer control means and which is to be read from the first buffer means by the DMA transfer processing and which is to be written to the second buffer means. PI included
An MPEG-TS transmission device, comprising: rewriting control means for controlling rewriting processing for rewriting the value of D (packet identifier) / continuity counter. 5. When the continuity counter values of two consecutive TS packets become discontinuous, the rewrite control means inserts a dummy TS packet between the two TS packets. 5. The MPEG-TS transmitting apparatus according to claim 4, wherein the respective values are made continuous. 6. An MPEG-TS transmission device for multiplexing and transmitting a transport stream used in the MPEG system, comprising: a storage unit for storing a plurality of transport streams; and a plurality of storage streams stored in the storage unit. The transport stream is divided into TS packets and multiplexed,
Multiplex transmission means for transmitting as one multiplexed stream; conversion means provided in connection with the storage means for converting the format of input data to the storage means; storage means provided in connection with the storage means; A first buffer means for temporarily storing output data from the multiplex transmitting means, a second buffer means for temporarily storing input data to the multiplex transmitting means, and DMA transfer control means for controlling DMA transfer processing for directly transferring data from the first buffer means to the second buffer means, wherein the conversion means is suitable for the DMA transfer processing.
An MPEG-TS transmission device, which converts a format of input data to the storage means. 7. A TS packet provided along with the DMA transfer control means and included in a TS packet to be read from the first buffer means and written to the second buffer means by the DMA transfer processing. Rewriting control means for controlling a rewriting process for rewriting a value of a PID (packet identifier) / continuity counter, wherein the conversion means further inputs control information necessary for the rewriting processing to the storage means. The MPEG-TS transmission device according to claim 6, wherein the MPEG-TS transmission device is added to data. 8. The MPEG-TS transmitting apparatus according to claim 7, wherein the control information includes information indicating a head position of a GOP. 9. The MPEG-TS transmission device according to claim 7, wherein the control information includes information indicating a head position of an I frame. 10. The rewriting control means, when each value of a continuity counter of two consecutive TS packets becomes discontinuous, inserts a dummy TS packet between the two TS packets. 8. The MPEG-TS transmitting apparatus according to claim 7, wherein each of the values is made continuous. 11. The conversion means according to claim 1, wherein the value of the continuity counter of the TS packet including the head position of the GOP or the head position of the I frame is set to 0.
TS including the start position of OP or the start position of I frame
8. The MPEG-TS transmitting apparatus according to claim 7, wherein a dummy TS packet is inserted immediately before the packet.