JP4419785B2 - Multiplexed packet generating apparatus and multiplexed packet generating method - Google Patents

Description

  The present invention relates to a multiplexed packet generation apparatus and a multiplexed packet generation method, and more particularly to a multiplexed packet that generates a multiplexed packet including at least a header portion and an information portion from elementary streams that are sequentially stored in a buffer and sets the multiplexed packet in the stream buffer. The present invention relates to a generation device and a multiplexed packet generation method.

  Conventionally, in a multiplexed packet generating apparatus that generates multiplexed packets, an encoder packetizes an ES (Elementary Stream) obtained by encoding a baseband signal such as video or audio by a multiplexer. The multiplexer includes a control unit that performs packet generation scheduling, and a processing unit that receives a processing instruction generated by the control unit, transfers data specified in accordance with the processing instruction, and generates a packet. Usually, the control unit is configured by a processor that executes processing according to a procedure described in the program and a storage medium that stores the program, and the processing unit is configured by hardware that performs high-speed data transfer.

  A processing procedure of the control unit that schedules packet generation will be described. FIG. 8 is a flowchart showing the procedure of a conventional multiplexed packet generation process. In actual packet generation, corresponding processing is performed for each of the audio ES and video ES, but detailed individual procedures are omitted, and common processing procedures are described.

  Packet generation is performed for each access unit of ES. First, it is determined whether there is video unit information output from the video encoder and access unit AU (Access Unit) information related to the audio ES information output from the audio encoder (step S101). If not, wait until they are complete. If it exists, it is determined whether or not to create a packet (step S102). If not, the process returns to step S101. If it is to be executed, a TS header is created (step S103), it is determined whether it is the head of the frame (step S104), and if it is the head, a PES header is created (step S105). Since the header is created by the procedure so far, a command for placing the created header in the stream buffer is created (step S106), and a command for placing the header is output to the processing unit (step S107). As a result, the processing unit transfers the header created in step S106 to the stream buffer. Subsequently, the control unit creates a command for placing the payload in the stream buffer (step S108), and outputs a command for placing the payload to the processing unit (step S109). As a result, the processing unit transfers the ES generated by the encoder as a payload to the stream buffer, and generates a PES.

  FIG. 9 is a diagram showing an example of packet generation according to a conventional multiplexed packet generation processing procedure. (A) shows the state of the stream buffer after execution of a command for placing a header, (B) for execution of a command for placing a payload, and (C) showing the state of the stream buffer after execution of a command for placing the next header.

  In step S107 of the procedure described above, the processing unit that has received the command for placing a header regarding the access unit n_v # 01, the TS header (TH) 901, the PES header generated by the control unit as shown in (A). (PH) 902 is set in the stream buffer 900. Next, when a command for placing a payload is received in step S109, the corresponding ES is searched from the storage device storing the ES, transferred to the buffer, and the payload 903 is set as shown in (B). Thus, a packet for one access unit is created. Subsequently, regarding the next access unit, n_v # 02, the processing unit that has received the header placement command sets the TS header (TH) 904 generated by the control unit in the buffer, as shown in (C).

Conventionally, when executing such a processing procedure, the control unit outputs a command to the processing unit and then waits until the processing corresponding to the command is completed before giving the next instruction. Therefore, the CPU (Central Processing Unit), which is the control unit, effectively uses the processing power of the CPU by eliminating the time to wait until the processing is completed after giving an instruction to fetch the ES information stored in the memory. A multiplexed packet generation apparatus that achieves the above has been proposed (see, for example, Patent Document 1).
JP 2001-345770 A (paragraph numbers [0017] to [0025], FIG. 4)

However, the conventional multiplexed packet generation has a problem that it is difficult to increase the packet generation processing speed.
In the conventional multiplexed packet generation device, a command for placing a header and a command for placing a payload for each packet are created by multiplexing scheduling software, and data received by the hardware is transferred to the stream buffer. The packet was being generated.

  When hardware that performs data transfer processing executes a command, the command is first interpreted, and the processing is performed based on the interpretation. For example, in the case of DMA (Direct Memory Access) transfer, when a transfer source address, a transfer destination address, and a transfer size are specified, data in a specified area is transferred without going through the CPU. When data transfer is performed by hardware as described above, it is known that the ratio of time for command interpretation to the entire processing time is high. In other words, in general, when transferring the same size of data several times, increasing the size to be transferred at one time and reducing the number of command outputs reduces the transfer size and increases the number of command outputs. Compared to the case, the processing time is shortened and efficient data transfer can be performed.

  However, in the conventional multiplexed packet generation, as shown in FIGS. 8 and 9, a command for placing a header and a command for placing a payload are issued for each access unit, and the transfer of each data to the stream buffer is hard. Is done by wear. For this reason, as the number of packets increases, the number of processing instructions issued to hardware increases in proportion to the number of packets. If the number of packets to be generated is NP, the hardware must process 2NP processing instructions. As described above, since the transfer process is performed for each packet, there is a problem that the ratio of the time required for the interpretation of the processing instruction becomes high and the data transfer efficiency is lowered.

  In particular, in the case of TS multiplexing, the number of packets to be created is much larger than in the case of PS (Program Stream) multiplexing, and since writing is performed while switching in units of small data, it is necessary to interpret hardware instructions. The overhead is very large.

  In addition, in a packet generator that eliminates the waiting time until the end of processing by hardware, it is possible to effectively use the processing capacity of the CPU, but it is possible to reduce the overhead of instruction interpretation and improve the data transfer efficiency by hardware. Can not.

  The present invention has been made in view of these points, and provides a multiplexed packet generation apparatus and a multiplexed packet generation method that improve the efficiency of transfer processing to a stream buffer and speed up packet generation processing. With the goal.

  In order to solve the above-mentioned problems, the present invention provides a multiplexed packet comprising a multiplexing processing unit having temporary packet storage means and transfer means, and a multiplexing control unit having instruction group storage means, temporary packet creation means, and scheduling means. An apparatus is provided. A multiplexing packet including at least a header part and an information part is generated from the elementary stream sequentially stored in the buffer by the multiplexing control unit and the multiplexing processing unit, and set in the stream buffer.

  The temporary packet storage means of the multiplexing processing unit temporarily stores temporary packets to be transferred to the stream buffer. The transfer means transfers the data in the designated data transfer source area to the data transfer destination area in accordance with the data transfer command. The instruction group storage unit of the multiplexing control unit temporarily stores a data transfer instruction group that instructs the transfer of the elementary stream, which is output to the transfer unit of the multiplexing processing unit. The temporary packet creation means captures and analyzes the elementary streams sequentially stored in the buffer for each access unit, creates a temporary packet in which only header portion data is set, and stores the temporary packet in the temporary packet storage means. In addition, a data transfer command to be transferred to a designated area of a stream buffer for storing an elementary stream set in the information section is created and stored in the command group storage means. The scheduling means multiplexes the data transfer instruction for transferring the temporary packet stored in the temporary packet storage means to the stream buffer and the data transfer instruction stored in the instruction group storage means when a predetermined number of temporary packets are created. Output to the transfer means of the processing unit.

  According to such a multiplexed packet generating apparatus, the multiplexing control unit takes in the elementary streams sequentially stored in the buffer and controls the generation process of the multiplexed packet. Temporary packet creation means of the multiplexing control unit captures and analyzes the elementary stream in units of access, creates header data of the multiplexed packet, creates a temporary packet in which only the header data is set, and stores the temporary packet Store in the means. Further, based on the analysis result, a data transfer command for transferring the elementary stream data set in the information portion of the multiplexed packet to the stream buffer is created and stored in the command group storage means. Thus, a plurality of temporary packets are stored in the temporary packet storage means, and a data transfer instruction group related to the information portion of the corresponding multiplexed packet is set in the instruction group storage means. When a predetermined number of temporary packets are generated, the scheduling means transfers a data transfer instruction to the stream buffer of the temporary packets stored in the temporary packet storage means and a data transfer instruction stored in the instruction group storage means. Output to the means. The transfer means interprets the data transfer command, executes a transfer process of the temporary packet stored in the temporary packet storage means to the stream buffer, and then sequentially executes a transfer process of transferring the elementary stream to the information section. As a result, a multiplexed packet is generated on the stream buffer.

  Further, in order to solve the above-mentioned problem, in a multiplexed packet generation method for generating a multiplexed packet including at least a header part and an information part from an elementary stream sequentially stored in a buffer and setting the multiplexed packet in the stream buffer, multiplexing control is performed. The temporary packet creation means of each part analyzes the elementary stream for each access unit, creates a temporary packet in which header part data is set, stores the temporary packet in the temporary packet storage means, and sets the elementary data set in the information part A data transfer command to be transferred to the designated area of the stream buffer for storing the stream data is created and stored in the command group storage means, and the scheduling means of the multiplexing control unit uses the temporary packet creation means to generate a predetermined number of the Once the temporary packet is created, it is stored in the temporary packet storage means A data transfer instruction for transferring the temporary packet to the stream buffer and the data transfer instruction stored in the instruction group storage means are output, and the transfer means of the multiplexing processing unit outputs the data transfer output by the scheduling means An instruction is acquired, the temporary packet stored in the temporary packet storage means is transferred to the stream buffer according to the data transfer instruction, and the multiplexed packet is instructed according to the data transfer instruction of the instruction group storage means. There is provided a multiplexed packet generation method, wherein the elementary stream is transferred to a designated area of the stream buffer corresponding to an information section.

  In such a multiplexed packet generation method, a temporary packet in which the header data of the multiplexed packet is set is created by analyzing the input elementary stream of the access unit, and stored in the temporary packet storage means. Further, a data transfer command for transferring the elementary stream set in the information portion of the multiplexed packet to the designated area of the stream buffer is created and stored in the command group storage means. When a predetermined number of temporary packets have been created, a data transfer instruction for transferring the temporary packets stored in the temporary packet storage means to the stream buffer is output, and subsequently, the data transfer instructions stored in the instruction group storage means are read. Are output sequentially. In response to the data transfer instruction, the transfer means that acquired the data transfer instruction transfers the temporary packet in the temporary packet storage means to the stream buffer, transfers the elementary stream to the information section of the stream buffer, and creates a multiplexed packet on the stream buffer. To do.

  In the multiplexed packet generating apparatus and the multiplexed packet generating method of the present invention, the multiplexing control unit creates the header part data of the multiplexed packet with the process of generating a plurality of packets as one processing unit, and only the header part data Is created and temporarily stored, and when processing for one processing unit is completed, the temporarily stored temporary packets are written by hardware that performs transfer processing in a batch. Thereafter, a multiplexed packet is generated on the stream buffer by writing data in the corresponding information section. As described above, according to the present invention, data transfer instructions executed by hardware that performs transfer processing are batch data transfer of a plurality of header part data and data transfer of an information part, and the number of instructions can be reduced. As a result, it is possible to perform efficient data transfer processing of hardware that performs transfer processing, and it is possible to speed up the generation of multiplexed packets.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the concept of the invention applied to the embodiment will be described, and then the specific contents of the embodiment will be described.
FIG. 1 is a conceptual diagram of the invention applied to the embodiment.

  A multiplexed packet generation apparatus according to the present invention includes a multiplexing control unit 1 that controls processing for creating a multiplexed packet, and a multiplexing processing unit 2 that sets the multiplexed packet in the stream buffer 3 according to the multiplexing control unit 1. A multiplexed packet is generated from video ES 41 and video ES information 42, audio ES 51 and audio ES information 52 that are sequentially input.

  Here, each ES will be described. The video ES 41 is an ES in which a video baseband signal is encoded by an encoder (not shown), and the video ES information 42 includes a video ES buffer on which a video ES of each access unit is stored for each access unit. Information such as position, size, and decoding time is set. Similarly, the audio ES 51 is an ES in which an audio baseband signal is encoded by an encoder, and the audio ES information 52 is set with information such as the position and size on the buffer of the audio ES of each access unit. .

Next, each processing unit will be described.
The multiplexing control unit 1, based on the video ES information 42 and the audio ES information 52, has a scheduling unit 11 that schedules multiplexing processing, a provisional packet in which a header part is set, and a provisional packet that creates a data transfer command for the information part. The packet creation means 12 and the temporary packet creation means 12 have an instruction group storage means 13 for temporarily storing the data transfer instruction group created. In the scheduling unit 11 and the provisional packet creation unit 12, each processing function is realized by the CPU executing a program describing the processing content of the function that each processing unit should have. That is, the multiplexing control unit 1 is realized by software.

  The scheduling unit 11 manages the execution of the multiplexed packet generation processing procedure by the multiplexing control unit 1. When a predetermined number of temporary packets are generated by the temporary packet generation unit 12, the scheduling unit 11 generates the temporary packet generation unit 12. A data transfer instruction for transferring the provisional packet to the stream buffer 3 is created and output to the transfer means 21 of the multiplexing processing unit 2. Further, a data transfer instruction group for transferring the elementary stream data set in the information part of the temporary packet stored in the instruction group storage means 13 to the stream buffer 3 is output to the transfer means 21.

  The temporary packet creation means 12 takes in and analyzes the video ES information 42 or the audio ES information 52 for each access unit, creates the header part data of the multiplexed packet according to the analysis result, and the header part data and blank information. A temporary packet having a part is generated and stored in the temporary packet creating means 12. In the temporary packet, an area for the data of the information part calculated according to the analysis result is secured following the header part data. Further, when a multiplexed packet is generated, a data transfer instruction for transferring the data of the video ES 41 or the audio ES 51 set in the information section to the stream buffer 3 is created and stored in the instruction group storage means 13. In the video ES information 42 and the audio ES information 52, an address and a data size on a buffer in which the corresponding ES is stored are registered, and based on these, a data transfer source address and a transfer size are defined. The multiplexing control unit 1 manages the data transfer destination address on the stream buffer 3.

  The instruction group storage means 13 is a memory for temporarily storing a data transfer instruction group for transferring the elementary stream data set in the information section that was blank in the temporary packet created by the temporary packet creation means 12 to the stream buffer 3. It is.

  The multiplexing processing unit 2 includes a transfer unit 21 that sets a multiplexed packet in the stream buffer 3 in accordance with the data transfer command created by the multiplexing control unit 1 and a temporary storage that temporarily stores the header created by the multiplexing control unit 1. Packet storage means 22 is included. The transfer means 21 interprets the data transfer command and transfers the data directly from the area where the transfer source data is stored to the designated area of the transfer destination stream buffer 3 without using the CPU. That is, the multiplexing processing unit 2 is realized by hardware, and is characterized by being capable of high-speed data transfer. The temporary packet storage unit 22 is a memory accessible from the multiplexing control unit 1 and the transfer unit 21, and temporarily stores the temporary packet created by the temporary packet creation unit 12.

The operation of the multiplexed packet generator having such a configuration will be described.
In a buffer (not shown), video ES41, video ES information 42, audio ES51, and audio ES information 52 generated by an encoder are sequentially stored.

  In the multiplexing control unit 1, when an access unit ES is input to the buffer for each video ES 41 or audio ES 51, the temporary packet creation unit 12 takes in the video ES information 42 or the audio ES information 52, analyzes it, and analyzes the header. The partial data is set, and a temporary packet including the created header part data and a blank information part is created. In the blank information portion, an area corresponding to the size of the information portion calculated according to the analysis result is secured. The created temporary packet is stored in the temporary packet storage unit 22. Further, the video ES 41 or audio ES 51 data set in the information section is taken in, a data transfer command for transferring to the stream buffer 3 is created, and stored in the command group storage means 13. By repeating the above processing for each access unit, the temporary packet storage unit 22 stores a plurality of temporary packets in which only the header portion is set. Accordingly, the temporary packet storage unit 22 creates a temporary packet group having the same data configuration as the multiplexed packet group set in the stream buffer 3. However, the information part of the temporary packet is blank. The instruction group storage means 13 stores a data transfer instruction group for transferring valid data to the information portion of the multiplexed packet on the stream buffer 3 corresponding to the blank information portion stored in the temporary packet storage means 22. Is done.

  When a predetermined number of temporary packets are set in this way, a data transfer command for transferring the temporary packets to the stream buffer 3 is created by the scheduling means 11 and output to the transfer means 21. As a result, the transfer unit 21 transfers a plurality of temporary packets stored in the temporary packet storage unit 22 to the designated area of the stream buffer 3 at a time. As a result, the header portion data is set on the stream buffer 3, and the multiplexed packet with the blank information portion is set.

  Subsequently, the scheduling unit 11 outputs the data transfer instruction stored in the instruction group storage unit 13 to the transfer unit 21. For example, if data transfer commands are registered in a queue prepared in the transfer means 21, the processing load on the CPU of the multiplexing control unit 1 can be reduced. The transfer means 21 sequentially transfers the data of the video ES 41 or the audio ES 51 corresponding to the information portion of the multiplexed packet on the stream buffer that is blank according to the data transfer command. As a result, data is set in the information portion of the multiplexed packet on the stream buffer 3, and the multiplexed packet is completed.

  In this way, a plurality of temporary packets in which only the header data of the multiplexed packet is set are created on the temporary packet storage means 22 and transferred to the stream buffer 3 collectively by hardware that performs transfer processing. The hardware can set a plurality of header data on the stream buffer 3 by interpreting the instruction once. As a result, the processing efficiency of the hardware that performs the transfer process increases, and the transfer process can be speeded up.

  In the above description, the instruction group storage unit 13 is provided in the multiplexing control unit 1. However, the instruction group storage unit 13 may be provided on the memory of the multiplexing processing unit 2 readable / writable from the multiplexing control unit 1. Moreover, although the case where the elementary stream is a TS has been described, it can also be applied to a PS.

  In the following, the embodiment is applied to a multiplexed packet generation apparatus that takes in video ES and audio ES and generates PES from these ES based on the definition of MPEG2 (Moving Picture Experts Group 2). Details will be described with reference to FIG.

FIG. 2 is a block diagram showing the configuration of the multiplexed packet generation apparatus according to the embodiment of the present invention. The same parts as those in FIG.
A multiplexed packet generation apparatus according to an embodiment of the present invention includes a stream buffer 3, a multiplexing unit (software, hereinafter referred to as S / W) 10 configured by software and controlling multiplexing processing, and configured by hardware. A multiplexing unit (hardware, hereinafter referred to as H / W) 20 for performing a multiplexing process and setting multiplexed packets in the stream buffer 3, and a video encoder 40 for generating a video ES and video ES information from a video baseband signal , An audio encoder 50 for generating audio ES and audio ES information from an audio baseband signal, and a video ES buffer 61, a video ES information buffer 62, an audio ES buffer 63, and an audio ES information buffer 64 for storing the ES, respectively. .

  The multiplexing unit (S / W) 10 includes at least a CPU, a storage device that stores a program describing the processing contents of the function to be executed by the multiplexing unit (S / W) 10, and information generated by the processing procedure. Has a memory for storing. When the CPU executes the program, it functions as the multiplexing control unit 1 and realizes each processing means of the scheduling means 11 and the temporary packet creation means 12.

  The multiplexing unit (H / W) 20 includes a transfer device that directly transfers data between memories by hardware, and a buffer that can be accessed from the transfer device and the multiplexing unit (S / W) 10. The transfer device functions as the transfer means 21, interprets a data transfer command (hereinafter referred to as a command), and executes data transfer from the designated transfer source address to the transfer destination address at high speed. For example, it is constituted by DMA. It also has a queue memory, and interprets and executes commands registered in the queue in the order written. The buffer functions as temporary packet storage means 22 and stores temporary packets created by the multiplexing unit (S / W) 10. The buffer is constituted by a ring buffer, for example, and is managed by the multiplexing unit (S / W) 10. The multiplexing unit (S / W) 10 always manages how much data has been written in the buffer and how much the written data has been used by the transfer device, and sets temporary packets on the buffer.

  The video encoder 40 receives a video baseband signal, creates a compression-encoded video ES, and an ES of video ES information related to the video ES, and stores them in the video ES buffer 61 and the video ES information buffer 62, respectively. The video ES information stores the position of the target video ES on the buffer and the data size.

  The audio encoder 50 receives an audio baseband signal, creates a compression-encoded audio ES and audio ES information related to the audio ES, and stores them in the audio ES buffer 63 and the audio ES information buffer 64, respectively. The audio ES information stores the position of the target audio ES on the buffer and the data size.

The operation of the multiplexed packet generator having such a configuration will be described.
The video encoder 40 generates a video ES from the video baseband signals sequentially input and stores it in the video ES buffer 61, and also generates video ES information related to the video ES and stores it in the video ES information buffer 62. Similarly, an audio ES is generated from the sequentially input audio baseband signal and stored in the audio ES buffer 63, and audio ES information related to the audio ES is generated and stored in the audio ES information buffer 64.

  The multiplexing unit (S / W) 10 analyzes the video ES information stored in the video ES information buffer 62 and the audio ES information stored in the audio ES information buffer 64, creates respective temporary packets, and multiplexes them. Write to the buffer of the conversion unit (H / W) 20. The temporary packet includes header part data generated based on the analysis result and a blank payload. The size of the blank payload is defined according to the data size of the target video ES and audio ES registered in the video ES information and audio ES information. Further, similarly, a stream corresponding to a blank payload in a temporary packet using the position and data size on the buffer where the target video ES and audio ES registered in the video ES information and audio ES information are stored. A command for transferring payload data is created and temporarily stored so that data corresponding to the payload of the multiplexed packet on the buffer 3 is transferred.

  When a predetermined number of temporary packets are created, the multiplexing unit (S / W) 10 creates a command for transferring the temporary packet group set in the buffer to the stream buffer 3, and the multiplexing unit ( H / W) 20. The multiplexing unit (H / W) 20 interprets the command, and transfers a plurality of temporary packets set in the buffer to the stream buffer 3 at once.

  Subsequently, the multiplexing unit (S / W) 10 registers a command group for transferring temporarily stored payload data in the queue of the multiplexing unit (H / W) 20. The multiplexing unit (H / W) 20 interprets the commands in accordance with the order registered in the queue, and repeatedly performs the process of transferring the video ES and audio ES data to the payload area of the stream buffer 3.

  An example of the multiplexed packet set in the stream buffer 3 by the above transfer processing will be described. 3, 4, and 5 are diagrams illustrating an example of a state of the multiplexed packet on the stream buffer by the multiplexed packet generation process according to the embodiment of this invention. In the figure, the area surrounded by diagonal lines or grids indicates that valid data is set.

  Hereinafter, according to the command execution order, (A) after execution of a command for placing a header (FIG. 3), (B) after execution of a command for placing a payload (FIG. 4), and (C) after executing a command for placing the next payload (FIG. 5). The state of will be described.

  FIG. 3 shows the state of the stream buffer after execution of the header placement command. The command for placing the header is output from the multiplexing unit (S / W) 10 to the multiplexing unit (H / W) 20 after a predetermined number of temporary packets are stored in the buffer. The multiplexing unit (H / W) 20 collectively transfers the temporary packets set in the buffer to the stream buffer according to the command. Of course, before the command is executed, the same data as shown in FIG. 3 is stored in the buffer in which the temporary packet is stored.

  When a command for placing a header is executed, the stream buffer 3 stores a TS header (THn_v # 01) 101, a PES header (PHn_v # 01), and a blank payload (payload n_v) that constitute the temporary packet of the first video packet. # 01) 103 is transferred. Similarly, in the transfer process using the same command, the temporary packet of the second video packet (TS header 104, payload 105) and the temporary packet of the first audio packet (TS header 106, PES header 107, payload 108), 3 The tentative packet of the second video packet (TS header 109, payload 110), the tentative packet of the fourth video packet (TS header 111, payload 112), and the tentative packet of the second audio packet (TS header 113, payload 114) As described above, a plurality of temporary packets are transferred to the stream buffer 3. The valid data here are only the TS headers 101, 104, 106, 109, 111, 113 and the PES headers 102, 107.

FIG. 4 shows the state of the stream buffer after the command to place the first payload is executed.
When the command for placing the first payload is executed, the data of the target video ES is transferred to the blank payload 103 of the first video packet in the stream buffer 3 in the state shown in FIG. 3, and a valid payload 103a is set. Is done.

FIG. 5 shows the state of the stream buffer after execution of the command for placing the next payload.
When a command to place the next payload is executed, the data of the target video ES is transferred to the blank payload 105 of the second video packet in the stream buffer 3 in the state shown in FIG. 4, and a valid payload 105a is set. Is done.

  Thus, valid data is transferred to a blank payload by a command for placing a payload. The process is repeated until the setting of the payloads of all temporary packets is completed.

  By executing the above processing, the multiplexed packet set in the stream buffer 3 can be sent in order from the packet in which the payload is set. Note that the number of packets to be processed in a lump is appropriately set according to the access unit, transfer processing capability, buffer size, and the like. Moreover, it can also be set as the variable value according to a condition as needed.

Next, the multiplexed packet generation method of the embodiment will be described. FIG. 6 is a flowchart showing a procedure of the multiplexed packet generation method according to the embodiment of the present invention.
The following processing procedure shows a processing procedure executed by the multiplexing unit (S / W) 10, and when the provisional packet generation processing for the number of provisional packets preset by software (this is assumed to be NP) is completed. The processing is taken over by the multiplexing unit (H / W) 20.

[Step S1] Temporary packet generation processing by the multiplexing unit (S / W) 10 is started, and a counter (np) indicating the number of generated temporary packets is initialized to zero.
[Step S2] It is determined whether or not there is a video ES of an access unit and video ES information related to the video ES (hereinafter collectively referred to as video AU information). If there is no video AU information, it waits for video ES.

  [Step S3] When the video AU information exists, it is determined whether the audio ES of the access unit and the audio ES information related to the audio ES (hereinafter collectively referred to as audio AU information) exist. To do. If there is no audio AU information, the audio ES wait is continued.

  [Step S4] When both video AU information and audio AU information exist, provisional packet creation processing is performed based on each ES. Through the temporary packet creation process, header data is created, and a temporary packet with a blank payload added is stored in the temporary packet storage means. Further, a command for placing ES data in the payload of the stream buffer is created and temporarily stored. Detailed processing will be described later.

[Step S5] Since the provisional packet has been created, the number of provisional packets np is incremented by one.
[Step S6] The number of temporary packets np is compared with NP. If it does not exceed NP, the process returns to step S2 to perform the next ES process.

  [Step S7] When the number of temporary packets np is greater than or equal to NP, transfer processing is started. First, in order to transfer the temporary packet stored in the temporary packet storage means to the stream buffer, a command for placing a header is created.

[Step S8] The command for placing the header created in step S7 and the command for placing the temporarily stored payload are output to the H / W that performs the transfer process.
By executing the above processing procedure, a plurality of temporary packets are collectively transferred to the stream buffer, and then a payload is set.

Next, the temporary packet creation process will be described. FIG. 7 is a flowchart illustrating a procedure of temporary packet creation processing according to the embodiment of this invention.
[Step S11] It is determined whether to create an audio packet. If an audio packet is not created, the process proceeds to step S17.

[Step S12] When creating an audio packet, a TS header is first created and set in the header data storage area of the temporary packet.
[Step S13] Subsequently, it is determined whether or not it is the head of the frame (an access unit that is a unit of ES). If not, the process proceeds to step S15.

[Step S14] If it is the head of the frame, a PES header is created and set following the TS header in the header part data storage area of the temporary packet.
[Step S15] A blank payload is created and a temporary packet is generated. A blank payload is created by securing the area on the buffer.

  [Step S16] A payload creation command for placing the ES audio data set in the blank payload in the payload on the stream buffer is created and temporarily stored.

Through the above procedure, a temporary audio packet is created.
[Step S17] When an audio packet is not created, it is determined whether a video packet is created. If no video packet is created, the process ends.

[Step S18] When creating a video packet, a TS header is first created and set in the header part data storage area of the temporary packet.
[Step S19] Subsequently, it is determined whether or not it is the top of the frame. If not, the process proceeds to step S21.

[Step S20] If it is the head of the frame, a PES header is created and set following the TS header in the header part data storage area of the temporary packet.
[Step S21] A blank payload is created to create a temporary packet. A blank payload is created by securing the area on the buffer.

[Step S22] A payload creation command for placing the ES video data set in the blank payload in the payload on the stream buffer is created and temporarily stored.
A video temporary packet is created by the above procedure.

  Thus, in the temporary packet creation process, a temporary packet composed of a header portion and a blank payload is created and stored in the buffer. When the provisional packet creation is completed for one processing unit, batch transfer processing is performed.

  According to the multiplexed packet generating method in the multiplexed packet generating apparatus described above, the header portion of NP multiplexed packets can be transferred to the stream buffer with one command. As a result, the number of commands processed by hardware that performs transfer processing is NP + 1 when the number of packets is NP. In the conventional multiplexed packet generation method, in the case of the number of NP packets, 2NP commands have to be issued, so the number of commands can be reduced to (NP + 1) / 2NP, that is, approximately half. As a result, it is possible to reduce the overhead for interpreting commands by hardware, and it is possible to increase the speed of the multiplexing process. Particularly, it is suitable for a TS that has a very large number of packets and is switched in a small data unit, and thus overhead is a problem, and it is possible to increase the speed of TS multiplexing processing.

It is a conceptual diagram of the invention applied to embodiment. It is the block diagram which showed the structure of the multiplexed packet production | generation apparatus of embodiment of this invention. It is the figure which showed an example of the state of the multiplexed packet on the stream buffer by the multiplexed packet production | generation process of embodiment of this invention (after execution of the command which puts a header). It is the figure which showed an example of the state of the multiplexed packet on the stream buffer by the multiplexed packet production | generation process of embodiment of this invention (after the command which puts a payload). It is the figure which showed an example of the state of the multiplexed packet on a stream buffer by the multiplexed packet production | generation process of embodiment of this invention (after execution of the command which puts the next payload). It is the flowchart which showed the procedure of the multiplexed packet production | generation method of embodiment of this invention. It is the flowchart which showed the procedure of the temporary packet creation process of embodiment of this invention. It is the flowchart which showed the procedure of the conventional multiplexed packet production | generation process. It is the figure which showed an example of the packet generation by the procedure of the conventional multiplexed packet generation process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multiplexing control part, 2 ... Multiplexing process part, 3 ... Stream buffer, 10 ... Multiplexing part (S / W), 11 ... Scheduling means, 12 ... Temporary packet preparation means, 13 ... ... instruction group storage means, 20 ... multiplexing unit (H / W), 21 ... transfer means, 22 ... temporary packet storage means, 40 ... video encoder, 50 ... audio encoder

Claims (5)

In a multiplexed packet generation device that generates a multiplexed packet including at least a header part and an information part from an elementary stream that is sequentially stored in a buffer, and sets the multiplexed packet in the stream buffer,
Multiplexing processing unit comprising: temporary packet storage means for temporarily storing temporary packets to be transferred to the stream buffer; and transfer means for transferring data in a designated data transfer source area to a data transfer destination area in accordance with a data transfer command When,
Instruction group storage means for temporarily storing data transfer instructions for instructing transfer of data of the elementary stream, analysis of the elementary stream for each access unit, setting of header part data, and analysis result of the elementary stream Based on the data of the elementary stream set in the information part by creating a temporary packet that secures an area for storing the data of the information part following the header part data and storing it in the temporary packet storage means A temporary packet creating means for creating a data transfer instruction for transferring the data to the designated area of the stream buffer and storing it in the instruction group storage means, and when a predetermined number of the temporary packets are created by the temporary packet creating means, the stream back collectively the temporary packet stored in the temporary packet storage means A data transfer instruction to be transferred to § the multiplexing control unit having, a scheduling unit that outputted the data transfer instruction stored in the instruction group storage to the transfer means,
A multiplexed packet generation apparatus comprising: The transfer means of the multiplexing processing unit includes a queue buffer for registering the data transfer instruction as a queue, and processes the data transfer instructions written in the queue buffer in order,
The scheduling means of the multiplexing control unit registers the data transfer instruction of the data stored in the temporary packet storage means and the data transfer instruction stored in the instruction group storage means in the queue buffer;
The multiplexed packet generation apparatus according to claim 1, wherein: The transfer means of the multiplexing processing unit interprets the data transfer command and transfers data directly from the data transfer source device designated by the data transfer command to the data transfer destination device without passing through the multiplexing control unit. multiplexed packet generating apparatus according to claim 1, characterized in that. The elementary stream is generated by encoding a video or audio baseband signal based on the MPEG2 (Moving Picture Experts Group 2) standard by an encoder.
The provisional packet creation means of the multiplexing control unit sets each data of a PES (Packetized Elementary Stream) header part, a TS (Transport Stream) header part, and an adaptation field part based on MPEG2 regulations, and sets a payload part. The temporary packet that has been made blank is stored in the temporary packet storage means, and a data transfer instruction for transferring the elementary stream data set in the payload portion to the stream buffer is created and stored in the instruction group storage means To
The multiplexed packet generation apparatus according to claim 1, wherein:   In a multiplexed packet generation method for generating a multiplexed packet including at least a header part and an information part from an elementary stream sequentially stored in a buffer and setting the packet in a stream buffer,
  Temporary packet creation means of the multiplexing control unit analyzes the elementary stream for each access unit, sets header part data, and based on the analysis result of the elementary stream, the information part A data transfer that creates a temporary packet that secures an area for storing the data, stores the temporary packet in the temporary packet storage means, and transfers the data to the designated area of the stream buffer that stores the data of the elementary stream set in the information section Create an instruction and store it in the instruction group storage means,
  The scheduling unit of the multiplexing control unit collectively transfers the temporary packets stored in the temporary packet storage unit to the stream buffer when the predetermined number of the temporary packets are generated by the temporary packet generation unit. Outputting a data transfer instruction and the data transfer instruction stored in the instruction group storage means;
  The transfer unit of the multiplexing processing unit acquires the data transfer command output by the scheduling unit, transfers the temporary packet stored in the temporary packet storage unit according to the data transfer command to the stream buffer, and In accordance with the data transfer command of the group storage means, the elementary stream is transferred to the designated area of the stream buffer corresponding to the information portion of the instructed multiplexed packet.
  A multiplexed packet generation method characterized by the above.

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