JP6519304B2 - Data distribution device - Google Patents

Description

  The embodiments referred to herein relate to a data delivery apparatus and a data delivery method.

  2. Description of the Related Art Conventionally, for example, video (moving image: video) and audio (audio) captured by a surveillance camera or the like are transmitted to a network. At this time, the data distribution device (network interface) on the transmission side sends out data at the maximum transmission rate, but if the data amount exceeding the processing capacity of the control terminal on the reception side is burst transmitted, the data on the reception side terminal There will be a lack of

  Therefore, for example, the priority of the data type for which the transmission request has been received is determined, and the transmission time of the next packet of the same data type is determined from the data size of the generated packet and the transmission load (for example, bit rate) set. The network interface to calculate is being studied. Here, a network interface which calculates transmission time can be realized by using, for example, a descriptor type network interface.

  In the descriptor type network interface, for example, transmission priority and transmission timing between different data types such as video and audio can be controlled, but for example, data transmission of different loads with different data types such as high quality and low quality video is not good It is.

  By the way, conventionally, various data delivery apparatuses and data delivery methods for networks have been proposed.

Japanese Patent Application Publication No. 2007-074243 Japanese Patent Application Publication No. 2007-074740 WO 2004/075568 JP, 2006-273261, A JP, 2007-194732, A

  As described above, conventionally, the descriptor type network interface has been studied, but, for example, when performing data transmission of different loads with different data types such as high quality video and low quality video, it is dragged by either transmission load Appropriate transmission was difficult.

  Such a problem is not limited to the delivery of image data, and is the same as in other various data delivery. In the present specification, high-quality moving images (high-quality video) and low-quality moving image data (low-quality video) are mainly described as an example, but the application of this embodiment is not limited thereto.

  Further, in the present specification, a channel is defined as data of different settings (for example, high quality Video and low quality Video having different resolutions) in the same data type (for example, moving image data).

According to one embodiment, a DMA unit that receives data from a data storage unit and performs DMA transfer, packet processing that receives transmission data from the DMA unit and generates a packet, and determines the data type of the packet And a data delivery apparatus including: The data distribution apparatus includes a priority determination unit, a transmission time management unit, a processing start determination unit, a current time detection unit, a transmission time comparison unit, a transmission timing calculation unit, and a packet data size calculation unit. And transmitting the generated packet to the network.

The priority determination unit receives the data type and determines the highest priority data type with the highest priority, and the transmission time management unit receives the highest priority data type , and the same data in each transmission data is received. It manages channel IDs for identifying channels that are data of different settings in type and transmission time of each channel. The processing start determination unit receives the output of the transmission time management unit, and determines whether the packet processing unit starts the corresponding packet processing. The current time detection unit detects the current time, the transmission time comparison unit compares the current time with the current packet transmission time, the transmission timing calculation unit calculates the transmission timing, and the packet data The size calculation unit calculates the size of packet data. The transmission time management unit outputs the current packet transmission time of the highest priority channel ID to the transmission time comparison unit from the highest priority data type, and outputs the channel ID to the processing start determination unit, and calculates the transmission timing. The current packet transmission time of the corresponding channel ID is updated based on the calculation result of the unit. The process start determination unit receives the comparison result from the transmission time comparison unit and the transmission channel ID to be transmitted from the transmission time management unit, and determines whether to start the transmission channel ID transmission process. The determination result and the transmission channel ID are notified to the packet processing unit, and the DMA unit and the packet data size calculation unit are notified of a channel ID for starting transmission processing.

  The disclosed data delivery apparatus and data delivery method have an effect that transmission timing control can be performed for each channel without increasing the transmission data buffer.

FIG. 1 is a diagram for explaining an example of a surveillance camera system. FIG. 2 is a block diagram showing an example of a related art descriptor type network interface in the surveillance camera system shown in FIG. FIG. 3 is a flowchart for explaining an example of the operation of the network interface shown in FIG. FIG. 4 is a diagram for explaining a DMA unit in the network interface shown in FIG. FIG. 5 is a diagram schematically showing the state of data transmission by the network interface shown in FIG. FIG. 6 is a block diagram showing a first embodiment of the network interface. FIG. 7 is a flowchart for explaining an example of the operation of the network interface shown in FIG. FIG. 8 is a diagram schematically showing the state of data transmission by the network interface shown in FIG. FIG. 9 is a diagram for comparing and explaining the transmission time management table in the related art and the network interface of the first embodiment. FIG. 10 is a diagram for explaining the operation of the processing start determination unit in the network interface shown in FIG. FIG. 11 is a diagram for explaining an example of the packet format. FIG. 12 is a diagram for explaining the operation of the transmission data buffer of the data storage unit and the DMA unit while showing the difference between the related art and the first embodiment. FIG. 13 is a block diagram showing a second embodiment of the network interface. FIG. 14 is a block diagram showing a modification of the network interface shown in FIG. FIG. 15 is a diagram for describing a problem when the number of channel IDs to be processed increases. FIG. 16 is a block diagram showing the main part of the third embodiment of the network interface. FIG. 17 is a block diagram showing the main part of the fourth embodiment of the network interface.

  First, before the data delivery apparatus and data delivery method of the present embodiment are described in detail, referring to FIGS. 1 to 5, the data delivery apparatus and data delivery method as related techniques, and monitoring the problems thereof A camera system will be described as an example.

  FIG. 1 is a diagram for explaining an example of a surveillance camera system. As shown in FIG. 1, the monitoring camera system receives data distribution from the monitoring camera 100 via the network 200 when the user 400 operates the control terminal 300, for example.

  Here, as data from the monitoring camera 100, for example, high quality moving picture (Video High), low quality moving picture (Video Low), audio (Audio), high quality still picture (JPEG High), low quality Still images (JPEG Low) and control information (metadata) are included. In the surveillance camera system, for example, data from a plurality of surveillance cameras 100 are collected in the control terminal 300 via the network 200, respectively, and the user 400 uses it.

  The surveillance camera 100 includes, for example, a camera module 110, an encoder 120, a processor 130, a memory 140, and a network interface 150. The camera module 110 captures (further, collects sound) around the surveillance camera 100 (for example, all around 360 °), and the encoder 120 encodes video (audio) data from the camera module 110 Do.

  The memory 140 stores data and control information encoded by the encoder 120, and the network interface 150 reads the data and control information from the memory 140 and transmits (distributes) the control terminal 300 via the network 200. Here, the encoder 120, the memory 140 and the network interface 150 are controlled by the processor 130.

  The network interface 150 includes a DMA (Direct Memory Access) unit 1, a packet processing unit 2 and a PHY (PHYsical layer) unit 3. The DMA unit 1 reads, for example, data such as image data and control information (metadata) encoded and stored by the encoder 120 from the memory 140 and transfers the data to the packet processing unit 2.

  The packet processing unit 2 receives the data transferred from the DMA unit 1, generates, for example, a frame (packet) conforming to a network standard such as Ethernet (registered trademark), and outputs the frame (packet) to the PHY unit 3. The PHY unit 3 converts the packet from the packet processing unit 2 into a signal format to be actually transmitted, and outputs the converted signal to the network 200.

  Incidentally, for example, in the network interface 150, the DMA unit 1, the packet processing unit 2 and the PHY unit 3 do not have the function of determining the transmission priority and controlling the transmission timing.

  Therefore, if transfer data such as video, audio and control information sent from the monitoring camera 100 to the control terminal 300 via the network 200 exceeds the processing capability of the control terminal 300 on the receiving side, for example, the control terminal 300 Missing (for example, data Da0 in FIG. 1) occurs.

  Therefore, for example, a descriptor type network interface that determines the priority of the data type for which the transmission request has been received and calculates the transmission time of the next packet of the same data type from the data size of the generated packet and the set transmission load / Is being developed.

  FIG. 2 is a block diagram showing an example of a related art descriptor type network interface in the surveillance camera system shown in FIG.

  As shown in FIG. 2, the network interface (data distribution device) 150 includes a DMA unit 1, packet processing unit 2, PHY unit 3, transmission time management unit 41, current time detection unit 42, transmission time comparison unit 43, priority. It includes a degree determination unit 44 and a transmission timing calculation unit 45. Here, the DMA unit 1 is formed as a descriptor type DMA.

  As described above, the DMA unit 1 reads data such as image data and control information from the memory (data storage unit) 140, for example, and transfers the data to the packet processing unit 2. The transmission data buffer (# 0 to #n) And 11) and a transmission data information storage unit (# 0 to #n) 12.

  Here, the transmission data buffer 11 and the transmission data information storage unit 12 are provided for each data type (for example, moving image data, audio data, still image data, etc.).

  The packet processing unit 2 receives the data transferred from the DMA unit 1, generates a packet conforming to the standard of the network, and outputs the packet to the PHY unit 3. The packet processing unit 2 includes a transmission request detection unit 21 and a packet generation unit 22.

  FIG. 3 is a flowchart for explaining an example of the operation of the network interface shown in FIG. 2. The network interface 150 of the related art will be described with reference to FIGS. 2 and 3. In FIG. 1 and FIG. 2, each process (steps ST10 to ST19) indicates the corresponding one.

  As shown in FIGS. 2 and 3, when the data storage unit (memory) 140 sets transmission data information and makes a transmission request, the DMA unit 1 transmits the data type of the transmission request from the data storage unit 140. The data is transferred to the transmission data buffer 11 for each data type mounted inside.

  That is, the transmission data read from the data storage unit 140 is stored in the internal buffer (the transmission data buffer 11 and the transmission data information storage unit 12) (ST1). Then, when data storage in the transmission data buffer 11 (internal buffer) is completed, a transmission request is made to the packet processing unit 2.

  First, the DMA unit 1 notifies the packet processing unit 2 of transmission data information such as transmission (storage) data size, data type and other control information (ST10), and the packet processing unit 2 is notified from the DMA unit 1 The priority determination unit 44 is notified of the data type for which there is a transmission request (ST11).

  The priority determination unit 44 determines the priority of the data type notified from the packet processing unit 2 (ST2), and notifies the transmission time management unit 41 and the packet processing unit 2 of the highest priority data type with the highest priority. To do (ST12).

  The transmission time management unit 41 notifies the transmission time comparison unit 43 of the current packet transmission time of the notified highest priority data type (ST13), and the current time detection unit 42 determines that the current time is the transmission time comparison unit 43 and It is output to the transmission timing calculation unit 45 (ST13).

  The transmission time comparison unit 43 compares the current packet transmission time with the current time to determine whether the transmission time has been reached (ST3), and notifies the priority determination unit 44 and the packet processing unit 2 of the comparison result (ST3). ST14). Here, when the transmission time is not reached (ST3: not reached), the priority determination processing request is notified to the priority determination unit 44, and the priority determination unit 44 performs the next priority determination processing. carry out.

  On the other hand, when the transmission time has been reached (ST3: arrival), the packet processing unit 2 starts packet generation processing of the data type notified in ST12. The packet processing unit 2 notifies the transmission load information to the transmission timing calculation unit 45 from the transmission data information notified in ST10 (ST15).

  The DMA unit 1 outputs the transmission data to the packet processing unit 2 from the transmission data buffer 11 corresponding to the notified data type (ST16). The packet processing unit 2 performs packet generation processing (ST4), and notifies the generated packet data size to the transmission timing calculation unit 45 (ST17) in order to calculate the transmission timing of the next packet during the packet generation processing.

  The transmission timing calculation unit 45 calculates the next packet transmission time from the current time notified in ST13, the transmission load notified in ST15, and the generated packet data size notified in ST17 (ST5). It notifies (ST18). After completing the packet generation process, the packet processing unit 2 outputs transmission data to the PHY unit 3 (ST19).

  FIG. 4 is a diagram for explaining a DMA unit in the network interface shown in FIG. As shown in FIG. 4, the DMA unit 1 includes a transmission data buffer 11 (a buffer for video, a buffer for audio and a buffer for JPEG), and a transmission data information storage unit 12 (a buffer for control information).

  The memory (data storage unit) 140 includes data (Vide (high image quality), Vide (low image quality), Audio, JPEG (high image quality) and JPEG (low image quality)) encoded by the encoder 120 and control information (meta Data) is stored.

  Then, the data and control information stored in the memory 140 are read out and stored in the transmission data buffer 11 and the transmission data information storage unit 12 of the DMA unit 1 in the network interface 150.

  Here, for example, as indicated by a reference code PP1, data of different settings (different) of the same data type of Vide (high image quality: high quality moving image data) and Vide (low image quality: low image quality moving image data) The channel data) share the same transmission data buffer (11).

  Also, as indicated by the reference code PP2, data of different channels of JPEG (high image quality: high image quality still image data) and Vide (low image quality: low image quality still image data) are also the same transmission data buffer (11) Share. The channel indicates data of different settings (for example, different resolutions) in the same data type (for example, moving image data or still image data).

  FIG. 5 is a diagram schematically showing the state of data transmission by the network interface shown in FIG. In FIG. 5, reference symbol a indicates past (previously transmitted) low-quality moving image (video: Video) data, and b indicates high-quality Video data transmitted previously.

  Further, reference symbols c, e, f, h indicate low-quality video data to be transmitted from now on, and d, g, i, j indicate high-quality video data to be transmitted from now on. Further, reference symbol I11 indicates a transmission interval calculated from the data size of a, I12 indicates a transmission interval calculated from the data size of b, and I13 indicates a transmission interval calculated from the data size of f. Here, for example, when the size of the low image quality Video data f is larger than the size of the low image quality Video data a, I13 is longer than I11.

  As shown in FIG. 5, for example, data is stored in the memory 140 in the order in which the processing of the encoder 120 is finished, that is, data is stored in the order of c, d, e, f, g, h, i. Be done. Further, in the internal buffer (transmission data buffer 11) of the DMA unit 1, for example, data is read from the memory 140 and stored according to the order of transmission requests notified from the processor.

  That is, the transmission data buffer 11 in the DMA unit 1 stores the same c, d, e, f, g, h, i in the same order as stored in the memory 140. here. For example, as indicated by the reference code Xg, for example, when the high quality Video data g overlaps the low quality Video data e, it becomes difficult to keep the original transmission interval of the high quality Video data. In addition, when a large amount of low image quality Video data is stored between high image quality Video data, the transmission interval of the high image quality Video data may become longer than the frame interval, and the reproduction may be stopped.

  That is, generally, the transmission bit rate of low image quality Video data is set to a low value, and conversely, the transmission bit rate of high image quality Video data is set to a high value. Therefore, in the case of the same data size, the transmission interval is long for low quality video data, and the transmission interval is short for high quality video data.

  In the network interface of the related art described with reference to FIGS. 2 and 3, when data of different channels are transmitted with the same data type, the data storage unit (memory) 140 or the DMA unit 1 prioritizes each channel And it is difficult to recognize the transmission timing.

  The memory 140 makes a transmission request to the DMA unit 1 from the data for which the encoding process is completed, and the DMA unit 1 stores the data in the internal transmission data buffer 11 in the order stored in the memory 140.

  As described with reference to FIG. 4, since the DMA unit 1 is a buffer for each data type, the transmission order of each data type (for example, moving image, sound, still image, etc.) can be controlled. It is difficult to control the transmission order between channels sharing buffers.

  That is, it is difficult to sort data for controlling the transmission order between channels such as high image quality Video and low image quality Video in the same moving image (Video) data type as shown in FIG.

  Also, the packet processing unit 2 only transmits data in the order stored in the transmission data buffer 11 in the DMA 1 unit, and when the transmission data buffer 11 is shared, it is possible to control the transmission timing for each different channel. Have difficulty.

  Therefore, for example, when the transmission interval is wider than the transmission interval assumed by the high-quality video data and becomes wider than the frame interval of the video, the reproduction screen is stopped until the next frame data is received.

  Also, for example, since low quality video data is transmitted at intervals shorter than the assumed transmission interval, the control terminal can transmit a data amount exceeding the processing capability of the receiving side (control terminal 300) in burst. At 300, data loss will occur.

  Hereinafter, embodiments of the data delivery apparatus and the data delivery method will be described in detail with reference to the attached drawings. FIG. 6 is a block diagram showing a first embodiment of the network interface.

  As shown in FIG. 6, the network interface (data delivery apparatus) 250 of the first embodiment includes the DMA unit 1, packet processing unit 2, PHY unit 3, current time detection unit 42, transmission time comparison unit 43, priority. A determination unit 44 and a transmission timing calculation unit 45 are included.

  Further, the network interface 250 includes a transmission time management unit 46 to which a channel ID field is added, a packet data size calculation unit 47, and a processing start determination unit 48. Here, the DMA unit 1 is formed as a descriptor type DMA.

  As described above, the DMA unit 1 reads data such as image data and control information from the memory (data storage unit) 140 and transfers the data to the packet processing unit 2, for example. The transmission data buffer 13 and transmission data information storage Part 14 is included.

  Here, the transmission data buffer 13 and the transmission data information storage unit 14 in the first embodiment are the same as the transmission data buffer 11 and the transmission data information storage unit 12 in the related art described with reference to FIG. It is not necessary to provide # 0 to #n corresponding to the data type.

  The packet processing unit 2 receives the data transferred from the DMA unit 1, generates a packet conforming to the standard of the network, and outputs the packet to the PHY unit 3. The packet processing unit 2 includes a transmission request detection unit 21 and a packet generation unit 22.

  As apparent from the comparison between FIG. 6 and FIG. 2 described above, the packet generation unit 22 receives, from the packet data size calculation unit 47, a data size for generating one packet.

  That is, in the network interface 250 of the first embodiment, the transmission time management unit 46 additionally has a function of selecting a channel ID from the highest priority data type notified from the priority determination unit 44.

  In addition, whether the processing start determination unit 48 starts transmission processing of the notified channel ID based on the channel ID notified from the transmission time management unit 46 and the comparison result notified from the transmission time comparison unit 43 It has a function to make a judgment. Furthermore, the processing start determination unit 48 has a function of notifying the packet processing unit 2 of the determination result and the channel ID, and notifying the packet data size calculation unit 47 of the channel ID.

  The packet data size calculation unit 47 has a function of calculating the data size for generating one packet based on the channel ID from the processing start determination unit 48, and the packet has the calculated data size for generating one packet and the channel ID The processing unit 2 is notified. The transmission data buffer 13 and the transmission data information storage unit 14 for each data type installed in the DMA unit 1 are provided one by one.

  FIG. 7 is a flow chart for explaining an example of the operation of the network interface shown in FIG. 6, and the network interface 250 of the first embodiment will be described with reference to FIGS. 6 and 7, each process (steps ST20 to ST31) indicates the corresponding process.

  As shown in FIGS. 6 and 7, the data storage unit (memory) 140 sets transmission data information and makes a transmission request. When DMA unit 1 receives a transmission request, network interface 150 of the related art described with reference to FIGS. 2 and 3 loads the data of the data type requested for transmission from data storage unit 140 into DMA 1. The data is transferred to the transmission data buffer 11 for each data type.

  On the other hand, in the network interface 250 of the first embodiment, the DMA unit 1 notifies the packet processing unit 2 of only which data type transmission request has been made. That is, first, the packet processing unit 2 notifies the priority determination unit 44 of the data type for which there is a transmission request notified from the DMA unit 1 (ST20).

  The priority determination unit 44 determines the priority of the data type notified from the packet processing unit 2 (ST2), and notifies the transmission time management unit 46 of the highest priority data type (ST21). The transmission time management unit 46 determines the highest priority channel ID from the highest priority data type notified from the priority determination unit 44, notifies the processing start determination unit 48 of the channel ID (ST22), and the transmission time comparison unit 43 The current packet transmission time of the corresponding channel is notified to (ST22). Further, the current time detection unit 42 notifies the transmission time comparison unit 43 and the transmission timing calculation unit 45 of the current time (ST22).

  The transmission time comparison unit 43 compares the current packet transmission time notified from the transmission time management unit 46 with the current time notified from the current time detection unit 42, and determines whether the transmission time has been reached (ST3) ).

  Then, the transmission time comparison unit 43 notifies the processing start determination unit 48 and the priority determination unit 44 of the comparison result (ST23). If the transmission time has not reached (ST3: not reached), the process returns to the priority determination process (ST2) to determine the next highest priority data type.

  On the other hand, if the transmission time has been reached or exceeded (ST3: arrival), the processing start determination unit 48 determines the channel ID (ST22) notified from the transmission time management unit 46 as the packet data size calculation unit 47 and the packet processor 2 (ST24). Furthermore, the process start determination unit 48 notifies the packet processing unit 2 of the determination result of the process start (ST24), and requests the packet generation process start.

  The packet data size calculation unit 47 calculates the data size for generating one packet according to the data type of the channel from the channel ID notified from the processing start determination unit 48 (ST6), and notifies the DMA unit and packet processing unit To do (ST25). Further, the channel ID notified from the processing start determination unit 48 is notified to the DMA unit 1 (ST 25).

  The DMA unit 1 stores only the data size notified from the packet data size calculation unit 47 from the data storage unit 140 into the internal buffer of the DMA unit 1 (transmission data buffer 13) (ST7). Then, the packet processing unit 2 is notified of the stored data size and other control information (information of the transmission data information storage unit 14) (ST26).

  The packet processing unit 2 notifies the transmission load to the transmission timing calculation unit 45 (ST27), and the DMA unit 1 transfers the transmission data to the packet processing unit (ST28). The packet processing unit 2 starts packet generation processing (ST4), and at that time, notifies the transmission timing calculation unit 45 of the calculated generated packet data size (ST29).

  The transmission timing calculation unit 45 calculates the current time ST23 notified from the current time detection unit 42, the transmission load (ST27) notified from the packet processing unit 2, and the generated packet data size notified from the packet processing unit 2 (ST23). The transmission time of the next packet is calculated from ST29) (ST5).

  Furthermore, the transmission timing calculation unit 45 notifies the transmission time management unit 46 of the transmission time of the next packet (ST30). The transmission time management unit 46 updates the transmission time of the channel ID to be transmitted to the next packet transmission time notified from the transmission timing calculation unit 45. Then, the packet processing unit 2 outputs the generated transmission data of the packet to the PHY unit 3.

  As described above, according to the network interface of the first embodiment, the packet data size calculation unit 47 notifies the DMA unit 1 of the channel ID to be transmitted and the data size for generating one packet.

  The DMA unit 1 obtains the number (capacity) of the transmission data buffers 13 provided in the DMA unit 1 by acquiring data of the designated channel ID from the memory (data storage unit) 140 by the notified data size. Transmission timing control can be performed for each channel without increasing it.

  FIG. 8 is a diagram schematically showing the state of data transmission by the network interface shown in FIG. 6, and is a diagram corresponding to FIG. 5 described above. In FIG. 8, reference symbol a indicates past (previously transmitted) low-quality moving image (video: Video) data, and b indicates high-quality Video data transmitted previously.

  Further, reference symbols c, e, f, h indicate low-quality video data to be transmitted from now on, and d, g, i, j indicate high-quality video data to be transmitted from now on. Furthermore, reference code I21 is the transmission interval of the low image quality Video calculated from the data size of a, I22 is the transmission interval calculated from the data size of b of the high image quality Video, and I23 is calculated from the data size of g Indicates the transmission interval of high quality video. Here, I23 is longer than I22 because the data size of g is large.

  The reference code I24 indicates the transmission interval of the low image quality Video calculated from the data size of e, and I25 indicates the transmission interval of the low image quality Video calculated from the data size of f. Here, I24 becomes small as I24 becomes small when the shifted time of e is taken into consideration, and the load on the receiving side (control terminal 300) temporarily increases, so the time of sending e is set as a new reference time, Determine the transmission time of f. In addition, I25 is longer than I24 because the data size of f is large.

  As shown in FIG. 8, for example, data is stored in the memory 140 in the order in which the processing of the encoder 120 is completed, that is, data is stored in the order of c, d, e, f, g, h, i. Be done.

  However, in the present embodiment, the internal buffer (transmission data buffer 13) of the DMA unit 1 receives, for example, the order from the memory 140 according to the order notified from the packet processing unit 2 instead of the order of transmission requests notified from the processor. Data is read and stored.

  That is, unlike the data stored in the memory 140, the transmission data buffer 13 in the DMA unit 1 is stored in the order of d, c, g, i, e, j, f, h. here. For example, as indicated by the reference symbol Xe, for example, when the low image quality Video data e collides with the high image quality Video data i for the transmission time, for example, the order of processing is determined according to the newly determined priority.

  That is, processing of the low quality video data e is performed after processing of the high quality video data i. As a result, it is possible to control transmission timing for each channel without increasing the number of transmission data buffers 13 provided inside the DMA unit 1.

  FIG. 9 is a diagram for comparing and explaining transmission time management tables in the related art and the network interface of the first embodiment.

  Here, FIG. 9A shows a transmission time management table (transmission time management unit 41) of the transmission time management unit 41 in the network interface 150 of the related art shown in FIG. 2 described above. 9B shows a transmission time management table (transmission time management unit 46 to which a channel ID field is added) in the network interface 250 of the first embodiment shown in FIG. 6 described above.

  As shown in FIG. 9A, in the transmission time management table of the related art, data types (Video, Audio, JPEG, Control,...) And corresponding packet transmission times (Tvideo, Taudio, Tjpeg, Tctrl, ...) is only stored. In other words, the transmission time management table of the related art only manages the transmission time for each intermediate buffer of the DMA unit 1 (for each data type of the transmission data buffer 11).

  That is, in the network interface 150 of the related art, the highest priority data type information is acquired from the priority determination unit 44 (or table address generation unit), and the next packet transmission time of the corresponding data type is output to the transmission time comparison unit 43 Do. Furthermore, after generating the packet to be transmitted, the next packet transmission time of the corresponding data type is updated to the next packet transmission time acquired from the transmission timing calculation unit 45.

  On the other hand, as shown in FIG. 9B, a channel ID field is added to the transmission time management table (first transmission time management table 46) of the first embodiment. Here, as the channel ID, for example, the same value is not used even if the data type is the same. Note that FIG. 9B is a mere example, and it goes without saying that various modifications and changes can be made if the transmission time is managed for each channel ID.

  That is, in the network interface 250 of the first embodiment, the transmission time management table includes data types, channel IDs (0, 1, 2,...), And next packet transmission time (Tvideo_0, Tvideo_1) corresponding to the channel ID. , Tvideo_2, ...) are stored.

  Then, in the network interface 250 of the first embodiment, the highest priority data type information is acquired from the priority determination unit 44 (or table address generation unit), and the highest channel among the channel IDs belonging to the corresponding data type. Select the next packet transmission time of ID. Furthermore, the priority determination unit 44 outputs the next packet transmission time of the highest channel ID to the transmission time comparison unit 43 and outputs the channel ID to the processing start determination unit 48.

  Furthermore, after generating a packet to be transmitted, the next packet transmission time of the corresponding channel ID is updated to the next packet transmission time acquired from the transmission timing calculation unit 45. Note that the number of channel IDs, or which channel ID belongs to which data type, is determined in advance by the system, for example. Further, the priority between channel IDs can be determined in advance by the system, but may be the same priority.

  FIG. 10 is a diagram for explaining the operation of the processing start determination unit in the network interface shown in FIG. As shown in FIG. 10, the process start determination unit 48 acquires the channel ID from the transmission time management table (the transmission time management unit 46 to which the channel ID field is added).

  Furthermore, the processing start determination unit 48 receives the comparison result (transmission time comparison result) of the transmission time and the current time from the transmission time comparison unit 43. Here, when the transmission time comparison result indicates that the current time ≧ the next packet transmission time is satisfied, the packet processing unit 2 is notified of the determination result of the packet processing start together with the channel ID.

  On the other hand, if the transmission time comparison result satisfies the current time <the next packet transmission time, the transmission time comparison unit 43 does not reach the transmission time, so the transmission time comparison unit 43 determines the next priority with respect to the priority determination unit 44. Report the comparison result to carry out. The current time and the next packet transmission time can be compared, for example, by using a counter and comparing counter values.

  FIG. 11 is a diagram for explaining an example of the packet format, and shows an example of a general packet format. As shown in FIG. 11, one packet PF includes, for example, PF1 to PF4.

  Here, PF1 is a portion of substantially fixed size regardless of the data type, and PF2 is a portion whose size changes depending on the data type. The PF1 includes, for example, Internet Protocol (IP) in Ethernet (registered trademark), Transmission Control Protocol (TCP) / User Data Protocol (UDP) header, and Real-time Transport Protocol (RTP) header. Also, PF2 is, for example, a special header for each data type.

  Furthermore, PF3 indicates a payload (Payload), which is, for example, data excluding management information (header information) such as a destination address and a source address from the total size of the packet. Note that CRC (Cyclic Redundancy Check) has a fixed length regardless of the data type, and is used, for example, for error detection accompanying data transfer and the like.

  As described above, in the packet format, there are a header of a fixed size regardless of the data type and a header of a different size according to the data type. Further, since the upper limit of the data size of one packet is determined by the system, it can be seen that the size of the payload part (PF3) changes depending on the data type.

  FIG. 12 is a diagram for explaining the operation of the transmission data buffer of the data storage unit and the DMA unit while showing the difference between the related art and the first embodiment. By the way, for example, as in the related art described with reference to FIG. 2, if the packet data size calculation unit 47 is not provided, the DMA unit 1 transmits only the data size notified from the data storage unit 140. The data is stored in the data buffer 11 (13).

  When transmission data size ≦ payload size, even if all data stored in data storage unit 140 is transmitted, it does not exceed the packet data size upper limit, the residual data in transmission data buffer 11 (13) of DMA unit 1 There is no.

  However, when transmission data size> payload size, the packet data size upper limit is reached before transmitting all the data stored in the data storage unit 140, so data remains in the transmission data buffer 11 (13) of the DMA unit 1 Resulting in.

  That is, unless the transmission data buffer 11 (13) of the DMA unit 1 becomes empty, the data of the next channel can not be transferred, and since the transmission timing is controlled, the next transmission time does not arrive. It becomes difficult to obtain transmission data from the transmission data buffer 11 (13).

  As described above, when the data size is larger than the payload data size of the data type to which the channel belongs, packet data in a state where data remains in the transmission data buffer of the DMA unit when the packet processing unit generates one packet. It reaches the upper limit of the size.

  As described above, when data remains in the transmission data buffer 11 (13) of the DMA unit 1, it becomes difficult to process transmission data of other channels stored in the data storage unit 140. As a result, the residual data stored in the transmission data buffer 11 (13) of the DMA unit 1 is processed, and transmission completely stops until the transmission data buffer 11 (13) of the DMA unit 1 becomes empty. .

  Then, for example, when the time when the transmission completely stops is longer than one frame time of the moving image, the data of the next frame is not received on the receiving side, so the reproduction of the moving image is stopped. . That is, on the receiving side (the control terminal 300), since the expected timing data does not arrive, for example, there arises a problem that the reproduction of the moving image is stopped.

  On the other hand, as described with reference to FIG. 6, a packet data size calculation unit 47 is provided in the network interface 250 of the first embodiment. The size of the payload PF3 is calculated by, for example, the packet data size calculation unit 47 by determining the data type from the channel ID.

  That is, in the first embodiment, the packet data size calculation unit 47 determines the data type based on the channel ID notified from the processing start determination unit 48, and calculates the upper limit value of the data size for generating one packet.

  In other words, the packet data size calculation unit 47 calculates the data size of the portion of the payload PF3 in FIG. 11, and notifies the packet processing unit 2 and the DMA unit 1 of the calculation result.

  As described above, according to the first embodiment, in the packet data size calculation unit 47, no residual transmission data is left in the transmission data buffer 13 of the DMA unit 1 after the packet processing unit 2 processes one packet. Control.

  That is, the packet data size calculation unit 47 calculates the data size for generating one packet from the notified channel ID, and notifies the DMA unit 1 and the packet processing unit 2 of the data size.

  As a result, the DMA unit 1 can store data in the transmission data buffer 13 of the DMA unit 1 for the data size for generating one packet, and transmits it to the transmission data buffer 13 of the DMA unit 1 after one packet is generated. Data can be prevented from remaining.

  In the first embodiment described above, the packet data size calculation unit 47 notifies the DMA unit 1 of the channel ID to be transmitted, but there may be cases, for example, where there is no transmission data of that channel ID due to processing. .

  In that case, the DMA unit 1 waits until transmission data of the notified channel ID is stored in the data storage unit 140, and transmission is performed until transmission data of the notified channel ID is stored in the data storage unit 140. May stop. The influence of the stop of the transmission is as described above.

  FIG. 13 is a block diagram showing a second embodiment of the network interface, which prevents transmission from being stopped until transmission data of the notified channel ID is stored in the data storage unit 140. As shown in FIG.

  As apparent from the comparison between FIG. 13 and FIG. 6 described above, in the network interface 350 of the second embodiment, the DMA unit 1 is provided with a channel ID scanning unit (first channel ID scanning unit) 15. The channel ID scanning unit 15 scans (examines) whether transmission data of the channel ID notified from the packet data size calculation unit 47 is requested for transmission by the transmission data information stored in the transmission data information storage unit 14. .

  That is, the channel ID scanning unit 15 receives the notification of the channel ID from the packet data size calculation unit 47 (ST25), and scans the information of the transmission data information storage unit 14 of the DMA unit 1 whether or not the corresponding channel ID exists. (to scan. Further, the channel ID scanning unit 15 notifies the processing start determination unit 48 of the scanning result (ST32).

  The processing start determination unit 48 starts the channel ID and packet generation processing for the packet processing unit 2 if there is a transmission request for data of the channel ID to be transmitted from the scanning result of the channel ID scanning unit 15 of the DMA unit 1 The determination result is notified (ST24).

  It should be noted that the processing start determination unit 48 determines that the priority determination unit 44 starts the next priority determination if there is no request for transmission of data of the channel ID to be transmitted from the scanning result of the channel ID scanning unit 15. Is notified (ST33).

  FIG. 14 is a block diagram showing a modification of the network interface shown in FIG. 13, and the channel ID scanning unit (first channel ID scanning unit) 15 provided in the DMA unit 1 in FIG. 2-channel ID scanning unit 16).

  As apparent from the comparison between FIG. 14 and FIG. 13 described above, in the network interface 450 of this modification, when the DMA unit 1 is notified of the transmission request from the data storage unit 140, does the corresponding channel ID exist? The information in the transmission data information storage unit 14 is scanned.

  That is, the channel ID scanning unit 16 notifies the packet processing unit 2 of the transmission request based on the scanning result of the transmission data information storage unit 14, and all channel IDs (storage channel IDs) stored in the data storage unit 140. To notify.

  The packet processing unit 2 (packet generation unit 22) notifies the notified storage channel ID to the priority determination unit 44 (ST20), and the priority determination unit 44 transmits the notified storage channel ID to the highest priority data type. The channel ID is selected and notified to the transmission time management unit 46 (ST21).

  Thus, according to the second embodiment of the network interface (data distribution apparatus) shown in FIG. 13 and the modification thereof shown in FIG. 14, the transmission data of the notified channel ID is stored in the data storage unit It is possible to prevent the transmission from stopping.

  FIG. 15 is a diagram for explaining the problem when the number of channel IDs to be processed increases, and FIG. 15 (a) shows a state in which data of channel IDs # 0 to # 3 are processed. 15 (b) shows that channel ID's # 0 to # 4 are processed.

  As shown in FIG. 15 (a), in a situation where data # 0 to # 3 do not overlap, data D01 to D31, D02 to D01 to D31 of all cycles of channel IDs # 0 to # 3 regardless of priority. D32 and D03 to D33 are to be transmitted in order.

  On the other hand, as shown in FIG. 15B, when the data with the lowest priority of channel ID # 4 increases, for example, D41 of the first cycle collides with D02 of the second cycle, and The second cycle D42 collides with the third cycle D03.

  In this case, since the data D02 and D03 of channel ID # 0 has higher priority than the data D41 and D42 of channel ID # 4, the data with high priority is given to the place where the data collision occurs. D02 and D03 will be sent.

  Then, the low priority data D41 and D42 are not transmitted but are kept waiting, and the timing at which all the high priority data is lost, that is, the timing to transmit the data D43, is to transmit the data D41 for the first time. Will be able to

  That is, in the example shown in FIG. 15B, when the number of channel IDs to be processed increases, for example, data (# 4) of channel ID with low priority becomes difficult to be transmitted, and there is a possibility that it is not transmitted. .

  FIG. 16 is a block diagram showing the main part of the third embodiment of the network interface and is for solving the problem that the data (# 4) of the channel ID with low priority described above is not transmitted.

  As shown in FIG. 16, the network interface 550 of the third embodiment inserts a priority change unit 49 between the priority determination unit 44 and the transmission time management unit 46. The other configurations can be applied as they are to the first embodiment shown in FIG. 6 or the second embodiment shown in FIG.

  The priority changing unit 49 receives the skip count setting table 491 in which the relationship between the data type and the skip count is predetermined, and the highest priority data type from the priority determination unit 44 and the data type from the packet processing unit 2 A skip count control unit 492 is included.

  That is, the skip count control unit 492 acquires the data type to which the transmission request has been made from the packet processing unit 2, and acquires the highest priority data type from the priority determination unit 44. Then, the skip count control is performed with reference to the skip count (Skip_cnt_v, Skip_cnt_a, Skip_cnt_j, Skip_cnt_c) for each data type (Video, Audio, JPEG, control information) set in the skip count setting table 491.

  Here, the number of skips indicates the number of times of being not selected as the top priority data type for each data type. Then, when the number of skips reaches the predetermined number determined in advance, the skip count control unit 492 changes not the data type selected by the priority determination unit 44 but the data type in which the number of skips reaches the prescribed number. The transmission time management unit 46 is notified as the post highest priority data type.

  As a result, even if the channel ID data (# 4) having a low priority, if the number of skips reaches the specified number, it is preferentially output as transmission data.

  FIG. 17 is a block diagram showing the main part of the fourth embodiment of the network interface, and as with FIG. 16, in order to solve the problem that the data (# 4) of the channel ID with low priority described above is not transmitted. belongs to.

  As shown in FIG. 17, in the network interface 650 of the fourth embodiment, the transmission time management unit 46 is provided with a transmission time management table (second transmission time management table) 461 and a channel ID selection unit 462. .

  The transmission time management table 461 further includes a next packet transmission time limit value (Tvideo_0_lim, Tvideo_1_lim,..., Tvideo_13_lim) field in the transmission time management table described with reference to FIG. 9B.

  For example, the next packet transmission time limit value is notified to the transmission time management unit 46 from the transmission timing calculation unit 45 together with the next packet transmission time, and the next packet transmission time limit value of each channel is determined by the next packet transmission time limit value. Field is updated.

  Here, for example, in the case of a moving image, the next packet transmission time limit value corresponds to a time in which reproduction of the moving image stops on the receiving side unless transmission is performed by that time. Further, the relationship between the next packet transmission time limit value and the next packet transmission time is established between the next packet transmission time limit value and the next packet transmission time.

  In the network interface 650 of the fourth embodiment, for example, the transmission time comparison unit 43 in the network interface 250 of the first embodiment shown in FIG. 6 can be deleted.

  Then, instead of the transmission time comparison unit 43, the channel ID selection unit 462 is also received, the current time is compared with the next packet transmission time and the next packet transmission time limit value of each channel, and the channel starts transmission processing. Choose an ID.

  If there is a channel for which the current time> the next packet transmission time limit value holds, the channel ID selection unit 462 controls to transmit the channel ID with the highest priority. Therefore, the channel ID selection unit 462 causes the processing start determination unit 48 to compare the channel ID for which the current time> the next packet transmission time limit value holds, and instead of the deleted transmission time comparison unit 43. Notice.

  Also, for example, when there are a plurality of channel IDs reaching the next packet transmission time limit value, the channel ID to be transmitted is selected according to the channel ID priority determined in advance by the system.

  Furthermore, for example, if there is no channel ID for which the current time exceeds the next packet transmission time limit but there is a channel ID for which the next packet transmission time is over, process the channel ID and the comparison result. The start determination unit 48 is notified.

  In addition, there is no channel ID for which the current time exceeds the next packet transmission time limit value, but if there are a plurality of channel IDs for which the next packet transmission time exceeds, the channel ID The channel ID to be transmitted is selected according to the priority.

  When there is no channel ID that has reached the next packet transmission time limit value or the next packet transmission time either, the processing start determination unit 48 is notified of a comparison result that means that the processing is not started. Do.

  As described above, according to this embodiment, for example, even when different transmission loads are set for the same data type, data of the data type and channel ID expected at the timing expected by the receiving side can be transmitted. It will be possible. Furthermore, the receiving side (control terminal) can avoid receiving data that exceeds its processing capability, and as a result, it is possible to prevent the loss of data.

  As described above, the network interface (data distribution device) of this embodiment can perform various modifications and changes in accordance with the desired function. The above-described data delivery apparatus and data delivery method according to the present embodiment are mainly described by taking moving pictures (Video), audio (Audio), still pictures (JPEG) and the like taken by a surveillance camera etc as an example. Can be widely applied to the delivery of various data.

  Although the embodiments have been described above, all the examples and conditions described herein are for the purpose of assisting the understanding of the concept of the invention applied to the invention and the technology, and the examples and conditions described are particularly It is not intended to limit the scope of the invention. Also, such descriptions in the specification do not show the advantages and disadvantages of the invention. While the embodiments of the invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention.

Further, the following appendices will be disclosed regarding the embodiment including the above-described example.
(Supplementary Note 1)
The DMA unit includes: a DMA unit that receives data from a data storage unit and performs DMA transfer; and a packet processing unit that receives transmission data from the DMA unit to generate a packet and determines the data type of the packet. A data distribution apparatus for transmitting the received packet to a network,
A priority determination unit that receives the data type and determines the highest priority data type with the highest priority;
A channel ID for receiving the highest priority data type and identifying a channel in each transmission data, and a transmission time management unit that manages the transmission time of each channel;
A processing start determination unit that receives the output of the transmission time management unit and determines whether the packet processing unit starts the corresponding packet processing;
Data distribution apparatus characterized in that.

(Supplementary Note 2)
further,
A current time detection unit that detects the current time;
A transmission time comparison unit that compares the current time with the current packet transmission time;
A transmission timing calculation unit that calculates transmission timing;
The transmission time management unit outputs the current packet transmission time of the highest priority channel ID to the transmission time comparison unit from the highest priority data type, and outputs the channel ID to the processing start determination unit, and calculates the transmission timing. Update the current packet transmission time of the corresponding channel ID based on the calculation result of
The data delivery apparatus according to claim 1, characterized in that:

(Supplementary Note 3)
further,
A packet data size calculation unit for calculating the size of packet data;
The process start determination unit receives the comparison result from the transmission time comparison unit and the transmission channel ID to be transmitted from the transmission time management unit, and determines whether to start the transmission channel ID transmission process. The determination result and the transmission channel ID are notified to the packet processing unit, and the DMA unit and the packet data size calculation unit are notified of a channel ID for starting transmission processing.
The data delivery apparatus according to claim 2, characterized in that:

(Supplementary Note 4)
The packet data size calculation unit calculates the data size required to generate one packet from the transmission channel ID input from the processing start determination unit, and notifies the DMA unit and the packet processing unit of the calculation result. Do,
Appendix 3. The data delivery apparatus according to appendix 3, wherein

(Supplementary Note 5)
The DMA unit is
A transmission data buffer for reading out and storing only the data size notified from the packet data size calculation unit from the data storage unit;
A transmission data information storage unit for storing the data size and control information stored in the transmission data buffer;
Appendix 3. The data delivery apparatus according to Appendix 3 or 4.

(Supplementary Note 6)
The DMA unit further includes
The first channel ID scan unit scans whether transmission data of the channel ID notified from the packet data size calculation unit is requested to be transmitted by the transmission data information stored in the transmission data information storage unit.
The data delivery apparatus according to claim 5, characterized in that:

(Appendix 7)
The DMA unit further includes
When a transmission request is notified from the data storage unit, the second channel ID scanning unit scans the transmission data information storage unit whether or not the corresponding channel ID exists.
The data delivery apparatus according to claim 5, characterized in that:

(Supplementary Note 8)
The transmission time management unit
Including a first transmission time management table in which data type, next packet transmission time, and channel ID are associated;
The data delivery apparatus according to any one of appendices 1 to 7, characterized in that:

(Appendix 9)
The transmission time management unit
A second transmission time management table in which a data type, next packet transmission time, channel ID and next packet transmission time limit value are associated;
A channel ID selection unit that receives the current time and selects a channel ID based on the second transmission time management table;
The data delivery apparatus according to any one of appendices 1 to 7, characterized in that:

(Supplementary Note 10)
further,
A skip count setting table provided between the priority determination unit and the transmission time management unit and in which the relationship between the data type and the skip count is predetermined, and the highest priority data type from the priority determination unit Including a skip number control unit that receives the data type from the packet processing unit,
The data delivery apparatus according to any one of appendices 1 to 7, characterized in that:

(Supplementary Note 11)
The DMA unit is a descriptor type DMA,
The data delivery apparatus according to any one of appendices 1 to 10, characterized in that:

(Supplementary Note 12)
further,
And a PHY unit for transmitting the packet generated by the packet processing unit to the network.
The data delivery apparatus according to any one of appendices 1 to 11, characterized in that

(Supplementary Note 13)
The data stored in the data storage unit includes video data captured by a camera, and the video data includes moving image data or still image data of different resolutions corresponding to different channels.
The data delivery apparatus according to any one of appendices 1 to 12, characterized in that:

(Supplementary Note 14)
The camera includes a plurality of surveillance cameras,
The data distribution apparatus is a network interface that transfers data obtained by the plurality of cameras to a control terminal via the network.
The data delivery apparatus according to any one of appendices 1 to 13, characterized in that:

(Supplementary Note 15)
The DMA unit includes: a DMA unit that receives data from a data storage unit and performs DMA transfer; and a packet processing unit that receives transmission data from the DMA unit to generate a packet and determines the data type of the packet. A data distribution method for transmitting the received packet to a network,
Receiving the data type and determining the highest priority data type with the highest priority;
Receiving the highest priority data type and managing a channel ID for identifying a channel in each transmission data and a transmission time of each channel;
The packet processing unit determines whether to start the corresponding packet processing based on the highest priority data type, the channel ID, and the transmission time of each channel.
Data distribution method characterized by

REFERENCE SIGNS LIST 1 DMA unit 2 packet processing unit 3 PHY unit 11, 13 transmission data buffer 12, 14 transmission data information storage unit 15 channel ID scanning unit (first channel ID scanning unit)
16 channel ID scanning unit (second channel ID scanning unit)
21 transmission request detection unit 22 packet generation unit 41 transmission time management unit 42 current time detection unit 43 transmission time comparison unit 44 priority determination unit 45 transmission timing calculation unit 46 transmission time management unit (transmission time management unit to which channel ID field is added) (Transmission time management unit table, first transmission time management unit table)
47 packet data size calculation unit 48 processing start determination unit 49 priority change unit
100 surveillance cameras
110 Camera module
120 encoder
130 processor
140 Data Storage Unit (Memory)
150, 250, 350, 450, 550, 650 network interface
200 network
300 control terminal
400 users
461 Transmission time management table (second transmission time management table)
462 Channel ID Selection Unit
491 Skip count setting table
492 Skip count control unit

Claims (8)

The DMA unit includes: a DMA unit that receives data from a data storage unit and performs DMA transfer; and a packet processing unit that receives transmission data from the DMA unit to generate a packet and determines the data type of the packet. A data distribution apparatus for transmitting the received packet to a network,
A priority determination unit that receives the data type and determines the highest priority data type with the highest priority;
A channel ID for identifying a channel that is data of different settings in the same data type in each transmission data , and a transmission time management unit that manages the transmission time of each channel in the transmission data;
A processing start determination unit that receives the output of the transmission time management unit and determines whether the packet processing unit starts the corresponding packet processing;
A current time detection unit that detects the current time;
A transmission time comparison unit that compares the current time with the current packet transmission time;
A transmission timing calculation unit that calculates transmission timing;
And the packet data size calculation section for calculating the size of the packet data, the possess,
The transmission time management unit outputs the current packet transmission time of the highest priority channel ID to the transmission time comparison unit from the highest priority data type, and outputs the channel ID to the processing start determination unit, and calculates the transmission timing. Update the current packet transmission time of the corresponding channel ID based on the calculation result of
The process start determination unit receives the comparison result from the transmission time comparison unit and the transmission channel ID to be transmitted from the transmission time management unit, and determines whether to start the transmission channel ID transmission process. The determination result and the transmission channel ID are notified to the packet processing unit, and the DMA unit and the packet data size calculation unit are notified of a channel ID for starting transmission processing .
Data distribution apparatus characterized in that. The packet data size calculation unit calculates the data size required to generate one packet from the transmission channel ID input from the processing start determination unit, and notifies the DMA unit and the packet processing unit of the calculation result. Do,
The data distribution apparatus according to claim 1 , wherein The DMA unit is
A transmission data buffer for reading out and storing only the data size notified from the packet data size calculation unit from the data storage unit;
A transmission data information storage unit for storing the data size and control information stored in the transmission data buffer;
The data delivery apparatus according to claim 1 or 2 , wherein The DMA unit further includes
The first channel ID scan unit scans whether transmission data of the channel ID notified from the packet data size calculation unit is requested to be transmitted by the transmission data information stored in the transmission data information storage unit.
The data distribution apparatus according to claim 3 , wherein The DMA unit further includes
When a transmission request is notified from the data storage unit, the second channel ID scanning unit scans the transmission data information storage unit whether or not the corresponding channel ID exists.
The data distribution apparatus according to claim 3 , wherein The transmission time management unit
Including a first transmission time management table in which data type, next packet transmission time, and channel ID are associated;
The data distribution apparatus according to any one of claims 1 to 5 , characterized in that: The transmission time management unit
A second transmission time management table in which a data type, next packet transmission time, channel ID and next packet transmission time limit value are associated;
A channel ID selection unit that receives the current time and selects a channel ID based on the second transmission time management table;
The data distribution apparatus according to any one of claims 1 to 5 , characterized in that: further,
A skip count setting table provided between the priority determination unit and the transmission time management unit and in which the relationship between the data type and the skip count is predetermined, and the highest priority data type from the priority determination unit Including a skip number control unit that receives the data type from the packet processing unit,
The data distribution apparatus according to any one of claims 1 to 5 , characterized in that:

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