JP2006303724A - Shaping apparatus and shaping method for variable length frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaping apparatus for variable length frames capable of preventing missing packets. <P>SOLUTION: The shaping apparatus 200 includes: a queue buffer 210 for receiving an input of a signal outputted from a video server; a timing generator 220 that transmits a signal (queue selection signal) for selecting a buffer to which the queue buffer 210 transmits a packet in order to perform reading of an instructed packet; a counter 230 for outputting a signal for specifying a timing to specify the reading of the packet; a frequency divider 240 that receives an input of a reference clock signal and generates the same clock frequency as a bit rate on the basis of the signal; and a transmission buffer 260 for temporarily storing the signal from the queue buffer 210. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for transmitting a packet, and more particularly to a shaping apparatus and a shaping method for controlling transmission of a variable-length frame.

  Regarding so-called content distribution, there are services that transmit designated content in response to a distribution request from a viewer. The service includes, for example, video on demand (VOD). VOD distributes each content in response to each request from a plurality of viewers. In this case, from the viewpoint of transmission efficiency, it is advantageous to transmit content data, that is, video packets in a burst manner to one transmission channel. Therefore, video packets may be transmitted in bursts.

  In this case, the probability that a packet is lost increases due to the concentration of traffic to routers and other buffers connected to the network or due to restrictions on the receivable capacity of the buffer provided in the decoder on the viewer side.

Thus, for example, Japanese Patent Laid-Open No. 2001-211207 (Patent Document 1) discloses a packet transmission apparatus that can adjust the amount of data transmitted from a transmission terminal on a packet network to the network per unit time.
JP 2001-211207 A

  Therefore, if so-called shaping processing is executed in software in order to make the burst property uniform, the load on a CPU (Central Processing Unit) or other arithmetic device that executes the software may increase. In that case, when the load on the CPU reaches a peak, a delay in internal processing occurs, which may reduce the accuracy of the shaping processing. On the other hand, in order to relatively reduce the load on the CPU, it is necessary to increase the processing capacity of the CPU. In this case, since a high performance CPU is used, there arises a problem that the cost increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a shaping apparatus that can prevent a shaping process from being delayed.

  Another object of the present invention is to provide a shaping device that can suppress an increase in cost.

  Still another object of the present invention is to provide a shaping method capable of preventing a delay in shaping processing.

  In order to solve the above-described problems, according to one aspect of the present invention, a variable-length frame shaping apparatus includes stream input means for receiving a plurality of streams. Each of the plurality of streams includes a plurality of packets. The shaping device generates a plurality of signals for defining a timing for reading each of the plurality of packets based on a first storage means for storing each of the plurality of packets and a bit rate of each of the plurality of streams. Generating means, control means for reading out packets of a stream corresponding to each signal from the first storage means based on each signal generated by each of the plurality of generation means, and from the first storage means Second storage means for storing the read packet and transmission means for transmitting the packet stored in the second storage means are provided.

  Preferably, each of the plurality of generation units includes a bit rate generation unit that generates an equivalent bit rate of the plurality of streams, and a signal generation unit that generates a signal based on the equivalent bit rate.

  Preferably, each of the plurality of generating means has specific data for specifying the amount of data transmitted to the second storage means based on transmission of the packet from the first storage means to the second storage means. Acquisition means for acquiring, and timing signal generation means for generating a signal based on the bit rate of the stream and the specific data.

  Preferably, the acquisition unit acquires the length of the packet stored in the first storage unit. The timing signal generation unit generates a signal by subtracting the length of the packet acquired by the acquisition unit based on the bit rate of the stream data.

  Preferably, the acquisition unit acquires a transmission byte of a packet transmitted from the first storage unit to the second storage unit. The timing signal generation means generates a signal by subtracting the transmission byte based on the bit rate of the stream.

  Preferably, the variable length frame shaping device includes an input unit that receives an input of another packet output from another packet transmission device, and a switching control unit that switches between transmission of the other packet and transmission of the read packet. And further comprising.

  Preferably, the switching control means includes switching data storage means for storing first data for enabling transmission of packets by the transmitting means and second data for enabling transmission of other packets. Including. The first data and the second data are predetermined. The switching control unit causes the control unit to transmit a first control signal for reading a packet from the first storage unit based on the first data and the second data, and to transmit the stream data. Instruction means for exclusively outputting the second control signal to the packet transmitting apparatus.

  Preferably, the switching control means further includes a time measuring means for measuring time. The first data and the second data are ratios determined in advance in order to use a band for transmitting stream data. The command means switches between the output of the first control signal to the control means and the output of the second control signal to the packet transmitting apparatus based on the time measured by the time measuring means and the predetermined ratio.

  Preferably, the switching control means includes a packet detection means for detecting the presence / absence of a packet based on a signal input via the input means, a temporary storage means for temporarily storing a packet from another packet transmission device, Whether to output the packet stored in the first storage means based on the idle detection means for detecting the presence or absence of the output of the packet from the temporary storage means and the presence or absence of the packet and the presence or absence of the output of the packet. Judgment means for judging, and command means for sending a signal to the control means based on the result of judgment by the judgment means. The control means reads the packet stored in the first storage means based on the signal.

  Preferably, the switching control means includes an idle measuring means for measuring an idle time during which no packet is input to the input means, a cascade storage means for storing the packet and the idle time from the input means, and elapse of idle time When detecting the input of the packet to the input means until the idle time elapses, the command means for transmitting a signal to the control means so as to read the packet until the idle time elapses The storage control means for storing the packet input through the means in the cascade storage means, and the reading means for reading out the packet stored in the cascade storage means after the idle time has elapsed.

  Preferably, the first storage means includes a queue buffer that temporarily stores each of the plurality of packets. Each of the plurality of generating means includes a frequency divider that generates a bit rate of each of the plurality of streams, and a plurality of counters that count down based on the bit rate generated by the frequency divider. The control means includes a controller that controls the timing for reading out the packet stored in the queue buffer based on a signal output in accordance with each of the plurality of counters.

  According to another aspect of the present invention, a variable-length frame shaping method includes a step of receiving an input of a plurality of streams in an apparatus including storage means for electromagnetically storing data. Each of the plurality of streams includes a plurality of packets. The method includes a step of storing a plurality of packets in the storage means, and a step of generating a signal for defining a timing for reading each of the plurality of packets based on a bit rate of each of the plurality of streams, The method includes: reading out packets of a stream corresponding to each signal from the storage unit based on each generated signal; and transmitting the packet read from the storage unit.

  With the shaping device according to the present invention, it is possible to prevent a delay in shaping processing related to packet transmission.

  The shaping device according to the present invention eliminates the need for an arithmetic device having a high processing speed in order to realize the shaping process, and thus the cost required for the arithmetic device can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
With reference to FIG. 1, the usage aspect of the shaping apparatus 200 which concerns on the 1st Embodiment of this invention is demonstrated. FIG. 1 is a diagram illustrating a content distribution system 10 including a shaping device 200.

  The shaping apparatus 200 is connected to the video server 120. The shaping apparatus 200 receives a signal output from the video server 120. The video server 120 is connected to a content DB (Database) 110. In response to a read command from the video server 120, the content DB 110 reads video / audio data stored in advance and outputs it to the video server 120.

  The shaping apparatus 200 is further connected to the network 130. The network 130 is the Internet or other communication line. The network 130 may be a private network. A set top box 140 is connected to the network 130. The set-top box 140 includes a buffer 142 that temporarily stores data, and a decoder 144 that decodes data that has been compression-encoded. The set top box 140 is connected to the television 150.

  In response to the transmission request from the set top box 140, the shaping apparatus 200 sends an image corresponding to the identification data included in the transmission request to the set top box 140. The set top box 140 receives the video / audio signal from the shaping device 200 via the network 130 and temporarily stores it in the buffer 142. The decoder 144 decodes the video / audio signal stored in the buffer 142 and outputs it to the television 150.

  With reference to FIG. 2, the structure of the shaping apparatus 200 which concerns on this Embodiment is demonstrated. FIG. 2 is a block diagram illustrating a hardware configuration of the shaping apparatus 200. The shaping apparatus 200 includes a queue buffer 210, a timing generator 220, a counter 230, a frequency divider 240, and a transmission buffer 260.

  The queue buffer 210 receives the signal output from the video server 120. The queue buffer 210 includes a plurality of buffers partitioned in advance for storing each of a plurality of packets input as signals. The storage of each packet in the respective buffer is executed according to a predetermined standard. This reference is, for example, the order of numbers assigned in advance for each buffer, or the number of the buffer assigned in advance to the packet transmission source, but may be another reference.

  The timing generator 220 is electrically connected to the queue buffer 210. The timing generator 220 reads out the instructed packet by sending a signal (queue selection signal) for selecting a buffer for sending the packet in the queue buffer 210. The timing generator 220 is connected to the counter 230. The timing generator 220 selects a queue buffer in the queue buffer 210 based on the CR signal from the counter 230. The timing generator 220 further sends a PR signal for resetting a signal to be down-counted inside the counter 230 to the counter 230.

  The counter 230 is connected to the frequency divider 240. The frequency divider 240 receives a reference clock signal. The frequency divider 240 generates the same clock frequency as the bit rate based on the signal. The counter 230 generates a signal for controlling the transmission timing from the queue buffer 210 to the transmission buffer 260 based on the bit rate from the frequency divider 240.

  The transmission buffer 260 is electrically connected to the queue buffer 210. When the packet stored in the queue buffer 210 is read based on the queue selection signal from the timing generator 220, the read signal is sent to the transmission buffer 260. The transmission buffer 260 temporarily stores the signal from the queue buffer 210. When a packet is transmitted from the queue buffer 210 to the transmission buffer 260, the counter 230 acquires the byte length of the transmitted packet. The counter 230 stores the byte length in an internal memory (not shown), and measures the transmission amount from the queue buffer 210 to the transmission buffer 260 based on the bit rate from the frequency divider 240.

  With reference to FIG. 3, the data structure in shaping apparatus 200 according to the present embodiment will be described. FIG. 3 is a diagram illustrating an aspect of data storage in queue buffer 210.

  The queue buffer 210 includes a first queue buffer to an nth queue buffer that are preliminarily divided into a plurality of buffer areas. The first queue buffer stores data of the first content. The second queue buffer stores data of the second content. Similarly, the (n-1) th queue buffer stores data of the (n-1) th content. On the other hand, content data is not stored in the nth queue buffer. That is, only “NULL” data is stored.

  Here, each queue buffer is used separately according to the type of packet transmitted from the video server 210. For example, when the first content includes a plurality of packet data, the data of the first content is sequentially stored in the first queue buffer every time it is output from the video server 120. When the second content has a plurality of data, each data output from the video server 120 is sequentially stored in the second queue buffer.

  Storage of data for each content in each queue buffer is realized as follows, for example. First, in the video server 120, data for specifying a queue buffer transmitted for each content is stored in a memory (not shown). A transmission unit (not shown) of the video server 120 generates a transmission address with reference to the data, and streams the content data based on the address. As a result, the content data is stored in the queue buffer specified based on the address.

  With reference to FIG. 4, the control structure of shaping apparatus 200 according to the present embodiment will be described. FIG. 4 is a flowchart showing a procedure of processing executed by each hardware of the shaping device 200.

  In step S410, the counter 230 detects reading of content data from the queue buffer 210. In step S420, counter 230 obtains the transmission length length for transmission buffer 260 based on the read data. In step S430, counter 230 sets the transmission length length to the count value held therein.

  In step 440, the counter 230 receives the same byte clock as the bit rate from the frequency divider 240. In step S450, the counter 230 counts down the transmission byte length with the byte clock. In step S460, counter 230 determines whether or not the count value is zero. If counter 230 determines that the count value is 0 (YES in step S460), the process proceeds to step S470. If not (NO in step S460), the process proceeds to step S480.

  In step S470, counter 230 outputs the CR signal as an enable signal to timing generator 220. The timing generator 220 selects a specific queue buffer from the queue buffer 210 in response to the input of the enable signal. Each counter 230 corresponds to the queue buffer 210. Thus, the signal from a particular counter 230 corresponds to the selection of a particular queue buffer 210. When there are multiple queue buffers, the timing generator is selected so that each queue buffer is selected based on the priority of each enable signal, or according to the round-robin method or in ascending order of the number identifying the queue buffer. 220 executes a queue buffer selection process or a scheduling process. The round robin method is a method of using one resource in order. In the processing in the computer, each process is executed in order for a certain time. Since the round robin method is known, detailed description will not be repeated.

  In step S480, counter 230 outputs the CR signal as a disable signal. When the disable signal is input, the timing generator 220 temporarily stops the queue buffer selection for the queue buffer 210.

  In this way, the selection of the queue buffer by the timing generator 220 is controlled based on the signal from the counter 230.

  With reference to FIG. 5, the control structure of shaping apparatus 200 according to the present embodiment will be further described. FIG. 5 is a flowchart showing a procedure of processing executed by the timing generator 220. These processes are executed based on a signal from the counter 230.

  In step S510, timing generator 220 determines whether or not a CR signal is input from counter 230. If timing generator 220 determines that a CR signal is input from counter 230 (YES in step S510), the process proceeds to step S520. If not (NO in step S510), the process ends.

  In step S520, timing generator 220 determines whether or not the CR signal is an enable signal. If timing generator 220 determines that the CR signal is an enable signal (YES in step S520), the process proceeds to step S530. If not (NO in step S520), the process ends.

  In step S530, timing generator 220 determines whether or not a plurality of enable signals are input. If timing generator 220 determines that a plurality of enable signals have been input (YES in step S530), the process proceeds to step S540. If not (NO in step S530), the process proceeds to step S550.

  In step S540, timing generator 220 sequentially selects queue buffers corresponding to CR signals from queue buffer 210 based on a predetermined order.

  In step S542, the timing generator 220 determines whether content data exists in the selected queue buffer. If timing generator 220 determines that the content data exists in the queue buffer (YES in step S542), the process proceeds to step S544. If not (NO in step S542), the process ends.

  In step S544, the timing generator 220 reads the content data from the selected queue buffer and writes it in the transmission buffer 260. In step S546, timing generator 220 determines whether or not all queue buffers have been selected. If timing generator 220 determines that the selection has been completed (YES in step S546), the process ends. If not (NO in step S546), the process returns to step S544.

  In step S550, timing generator 220 selects a queue buffer corresponding to the CR signal. In step S552, the timing generator 220 determines whether content data exists in the selected queue buffer. If timing generator 220 determines that the content data exists in the queue buffer (YES in step S552), the process proceeds to step S554. If not (NO in step S552), the process ends. In step S554, the timing generator 220 reads the content data from the queue buffer 210 and writes it in the transmission buffer 260.

  With reference to FIG. 6, the packet transmission mode by shaping apparatus 200 according to the present embodiment will be described. FIG. 6 is a shaping diagram showing the output mode of the packet input to the shaping apparatus 200.

As shown in the diagram (A), a plurality of packets constituting specific content are intermittently input from the video server 120 to the shaping device 200. That is, the packet 610 is input to the shaping apparatus 200 at time t (10). At time t (20), the packet 620 is input to the shaping device 200. At time t (30), the packet 630 is input to the shaping apparatus 200. Here the packet 610 has a packet length _{L A.} Packet 620 has a packet length _{L B.} The packet length L _B is twice the packet length L _A. Packet 630 has a packet length _{L C.} Packet length _{L C} is the same as the packet length _{L A.}

Diagram (B) is a diagram showing a transmission mode when each packet input to shaping apparatus 200 is transmitted at an ideal bit rate. Here, an ideal bit rate is, for example, T (Mbps (Mega bit per second)). At this time, the time t _A for transmitting the packet 610 is calculated by L _A / T. The time t _B for transmitting the packet 620 is calculated by the formula L _B / T. The time t _C for transmitting the packet 630 is calculated by the formula L _C / T. When the time for transmitting each packet is specified in this way, transmission of the next packet is prohibited until the transmission time of the preceding packet elapses.

Specifically, as shown in the diagram (C), when transmission of the packet 610 is started from time t (10), transmission of the packet 620 is not performed until time t (21). In this case, the time between the times t (10) and t (21) corresponds to the time t _A necessary for transmitting the packet 610.

Similarly, when transmission of packet 620 is started at time t (21), transmission of packet 630 is not performed until time t (31). In this case, the time between the times t (21) and t (31) corresponds to the time t _B necessary for transmitting the packet 620. Further, the packet 630 starts to be transmitted from time t (31) and continues until time t (41). The time between the time t (31) and the time t (41) corresponds to the time t _C necessary for transmitting the packet 630. Therefore, for example, when there is a packet to be transmitted next to packet 630, the transmission is not performed until time t (41) elapses.

  In the above case, the period from time t (11) to time t (21) is used for transmission of other packets constituting other contents.

  As described above, according to shaping device 200 according to the present embodiment, reading and transmission of stream data temporarily stored in queue buffer 210 are controlled by timing generator 220. The timing generator 220 selects a queue buffer based on a signal output from the counter 230, reads data stored in the queue buffer, and writes it in the transmission buffer 260.

  The counter 230 monitors the transmission state of data from the queue buffer 210 to the transmission buffer 260 based on the bit rate input from the frequency divider 240. For example, the counter 230 measures the amount of data transmitted from the queue buffer 210 to the transmission buffer 230. The counter 230 sets the data amount to an initial value, and counts down based on the signal from the frequency divider 240. Until the counted value becomes 0, the counter 230 outputs a disable signal to the timing generator 220 so as to prohibit transmission of the next packet from the queue buffer 210 to the transmission buffer 260.

  In this way, transmission from the queue buffer 210 to the transmission buffer 260 can be prevented from becoming a so-called burst. As a result, a sudden increase in the load on the network 130 connected to the shaping apparatus 200 is prevented. In addition, loss of packets distributed by the shaping apparatus 200 is prevented. Such a deficiency can also be prevented in the network 130 or in the decoder 144 of the set top box 140.

  Further, the processing in the shaping apparatus 200 is realized not as software processing using a CPU but as hardware processing. Therefore, it is possible to prevent the processing delay that may occur when the CPU is used. Further, since it is not necessary to use a high-performance CPU, that is, a CPU having a fast processing operation, in order to prevent the delay, an increase in the cost of the shaping device 200 can be suppressed.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. The shaping apparatus according to the present embodiment is different from the above-described shaping apparatus 200 in that it can be cascade-coupled. With this cascade connection, even if there is a restriction in the area in the queue buffer 210, more stream data can be sequentially transmitted as packets.

  With reference to FIG. 7, the structure of the shaping apparatus based on this Embodiment is demonstrated. FIG. 7 is a block diagram showing a hardware configuration of shaping apparatus 700-1 according to the present embodiment. The shaping device 700-2 has the same configuration as the shaping device 700-1. For convenience of description, the generic names of the shaping devices 700-1 and 700-2 are represented as the shaping device 700 as appropriate.

  The shaping apparatus 700 includes a shaping unit 750, a cascade / own station switching circuit 800, a receiving unit 760, a cascade gate 770, an OR circuit 780, and a transmission buffer 260. The shaping unit 750 has the same hardware configuration as the shaping apparatus 200 shown in FIG. 2 except for the timing generator 720. Therefore, description of the configuration will not be repeated here.

  The shaping device 700-1 is cascade-connected to another shaping device 700-2 via a signal line. The receiving unit 760 receives a packet input from another shaping device 700-2. Receiving unit 760 sends the packet to cascade gate 770. The enable signal EN1 from the cascade / own station switching circuit 800 is input to the cascade gate 770. Cascade gate 770 switches the operation of the gate unit according to the signal. The cascade / own station switching circuit 800 is further connected to the shaping unit 750. The cascade / own station switching circuit 800 controls the sending of the packet by the shaping unit 750 by sending an enable signal EN2 to the shaping unit 750. The packet output from the shaping unit 750 is input to the OR circuit 780. The OR circuit 780 sends either the packet from the cascade gate 770 or the packet from the shaping unit 750 to the transmission buffer 260.

  The shaping unit 750 includes a timing generator 720, a queue buffer 210, a counter 230, and a frequency divider 240. Timing generator 770 receives input of enable signal EN 2 from cascade / own station switching circuit 800. The timing generator 720 selects a buffer in the queue buffer 210 and reads data based on the input of the enable signal EN2 and the signal from the counter 230. Since this process is the same as the process in the first embodiment, the description thereof will not be repeated here.

  Cascade / own station switching circuit 800 further receives an input of a cascade control signal from the outside. This signal is a signal for defining which of the shaping devices to output a packet when a plurality of shaping devices are connected. For example, the cascade / own station switching circuit 800 transmits the signal to the shaping device 700-2 connected to the shaping device 700-1, and controls the operation of the shaping device 700-2.

  In this way, since the number of queue buffers in which packets are stored can be physically increased, many types of packets can be distributed without causing packet loss compared to the case of using a single shaping device. can do.

  With reference to FIG. 8, the structure of the shaping apparatus 700 which concerns on this Embodiment is further demonstrated. FIG. 8 is a block diagram showing a hardware configuration of cascade / own station switching circuit 800. Cascade / own station switching circuit 800 includes an input circuit 810, a determination circuit 830, a clock 820, an output circuit 840, and a memory 900.

  The input circuit 810 receives an input of a cascade control signal. The input circuit 810 is electrically connected to the determination circuit 830. A signal input to the input circuit 810 is sent to the determination circuit 830. The determination circuit 830 is electrically connected to the clock 820. A signal from the clock 820 is input to the determination circuit 830. In addition, the determination circuit 830 is electrically connected to the memory 900.

  Based on the signal from the input circuit 810, the signal from the clock 820, and the data stored in the memory 900, the determination circuit 830 is connected to the shaping device 700-2 or its own station, that is, the shaping device 700- that is cascade-coupled. 1 is used to control the packet transmission timing. This control is executed in accordance with, for example, a preset bandwidth usage ratio. Determination circuit 830 sends a signal indicating which device sends the packet to output circuit 840.

  The output circuit 840 is electrically connected to the shaping device 700-2 and the shaping device 700-1. The output circuit 840 is further electrically connected to the cascade gate 770. Therefore, when the output circuit 840 outputs the signal generated by the determination circuit 830, the cascade gate 770 switches between opening and closing of the gate unit according to the signal. The shaping device 700-2 switches transmission of the packet in response to the signal from the output circuit 840. In addition, shaping device 700-1 executes processing for selecting a queue buffer and sending a packet in response to a signal from output circuit 840.

  With reference to FIG. 9, the data structure of the shaping apparatus based on this Embodiment is demonstrated. FIG. 9 is a diagram conceptually showing one mode of data storage in memory 900.

  Memory 900 includes an area 910 and an area 920. Data representing the connected device is stored in area 910. Data representing the band usage rate is stored in area 920. For example, when two shaping devices are cascade-coupled, data for identifying each of the first shaping device and the second shaping device is stored in area 910. In addition, the ratio at which the bandwidth allocated to each shaping device can be used is stored in the area 920, respectively.

  In the example shown in FIG. 9, the first shaping device, for example, the shaping device 700-2 can use the band for 30% of the preset unit time. The second shaping device, such as shaping device 700-2, can similarly use 70% of the bandwidth. Note that such a ratio is not fixed and may be changed according to data input via the input circuit 810. Further, the number of shaping devices that are cascade-coupled is not limited to two. More shaping devices may be connected. Furthermore, the band usage ratio may be changed according to the amount of packet transmission in the system configured by the shaping device.

  Here, with reference to FIG. 10, the state of operation | movement of the shaping apparatus which concerns on this Embodiment is demonstrated. FIG. 10 is a timing chart showing the operation state of each device when two shaping devices 700-1 and 700-2 are connected.

  As shown in the chart (A), each shaping device is selected according to the ratio specified in the memory 900. For example, the time zone 1010 is used for selecting a queue buffer in the shaping device 700-2. The time zone 1020 is used for selecting a queue buffer in the shaping apparatus 700-1. Here, the time constituted by the time zone 1010 and the time zone 1020 corresponds to a unit time that defines the operation of the shaping apparatuses 700-1 and 700-2 that are cascade-coupled.

  Thereafter, in the time zone 1030, the queue buffer is selected again in the shaping device 700-2. Further, in the time zone 1040, the queue buffer is selected in the shaping device 700-1.

  In such a case, the state of the control signal for each shaping device is shown in charts (B) and (C), respectively. As shown in the chart (B), that is, when transmitting a packet from the shaping device 700-2, the cascade / own station switching circuit 800 sends the enable signal EN1 set to “High” to the cascade gate 770. (Chart (B)). At this time, the cascade / own station switching circuit 800 sends the enable signal EN2 set to “Lo” to the shaping unit 750 (chart (C)). These signals are output from time t (1) to t (2).

  As a result, the cascade gate 770 switches its gate portion to open. Therefore, the packet from the shaping device 700-2 is sent to the OR circuit 780 through the cascade gate 770. On the other hand, in the shaping unit 750, the timing generator 720 does not perform queue buffer selection, packet reading, and transmission for the queue buffer 210. Therefore, no packet is transmitted from the shaping unit 750 to the OR circuit 780. As a result, the OR circuit 780 sends the packet from the shaping device 700-2 to the transmission buffer 260.

  Thereafter, at time t (2), the cascade / own station switching circuit 800 sends the enable signal EN1 set to “Lo” to the cascade gate 770 in order to stop the transmission of the packet from the shaping device 700-2. Send to Cascade gate 770 closes its gate portion, so that packet transmission to the OR circuit stops.

  On the other hand, the cascade / own station switching circuit 800 transmits the enable signal EN <b> 2 set to “High” to the shaping unit 750 in order to execute transmission of the packet from the shaping unit 750. As a result, the packet read by the shaping unit 750 is sent to the OR circuit 780. Thus, the packet from the shaping unit 750 is input to the transmission buffer 260 via the OR circuit 780. Thereafter, the packet is output to the outside of the shaping device 700-1.

  Thereafter, when the enable signals EN1 and EN2 are switched again at time t (3), processing similar to the processing at time t (1) is executed, and transmission from the shaping devices 700-1 and 700-2 is switched. .

  Here, with reference to FIG. 11, another aspect according to the present embodiment will be described. FIG. 11 is a timing chart showing signals output for temporarily stopping the shaping functions of the shaping apparatuses 700-1 and 700-2.

  As shown in the chart (A), when the “High” signal is basically output for the enable signal EN1, the “Low” enable signal EN1 may be output intermittently. In this case, packet transmission from the shaping device 700-2 is temporarily interrupted.

  Similarly, as shown in the chart (B), when the signal that is basically set to “High” is output for the enable signal EN2, the enable signal EN2 of “Lo” is intermittently output. Also good. In this case, packet transmission from the shaping unit 750 included in the shaping apparatus 700-1 is temporarily interrupted.

  In this way, even if the load fluctuates temporarily, it is possible to realize the function of shaping the packets from the cascade-joined shaping devices while preventing packet loss.

  As described above, according to the shaping device 700 according to the second embodiment of the present invention, the control signal for defining the operation in the other shaping devices that are cascade-coupled is transmitted to the other shaping device. Are sent out. By switching the transmission path of each packet in accordance with this control signal, packet transmission from each of the plurality of shaping devices can be controlled. Therefore, even if a plurality of shaping devices are connected, packet loss due to an increase in load on the communication line can be prevented. Even if the number of queue buffers is limited in a single shaping device, it is physically possible to secure more buffers, so that more streams can be distributed.

<Third Embodiment>
Hereinafter, a third embodiment of the present invention will be described. The shaping apparatus according to the present embodiment does not require feedback of a control signal for switching packet transmission to another shaping apparatus that is cascade-coupled, so that the shaping apparatus according to the second embodiment Different from the device 700.

  In the following description, the same elements are given the same numbers. Their functions are the same. Therefore, description thereof will not be repeated here.

  A shaping apparatus according to the present embodiment will be described with reference to FIG. FIG. 12 is a block diagram showing a hardware configuration of shaping apparatus 1200. The shaping apparatus 1200 includes a reception unit 1210, a packet detection circuit 1220, a packet delay buffer 1230, a determination circuit 1240, an IDLE detection circuit 1250, a shaping unit 750, an OR circuit 780, and a transmission buffer 260. The shaping device 1200 is connected to the shaping device 200 via a signal line 1202.

  The receiving unit 1210 is connected to the signal line 1202. The receiving unit 1210 is further electrically connected to the packet detection circuit 1220 and the packet delay buffer 1230. The packet detection circuit 1220 is electrically connected to the determination circuit 1240. The determination circuit 1240 is electrically connected to the IDLE detection circuit 1250. The packet delay buffer 1230 is electrically connected to the IDLE detection circuit 1250 and the OR circuit 780, respectively. The determination circuit 1240 is further electrically connected to the shaping unit 750.

  The packet output from the shaping device 200 is input to the receiving unit 1210 via the signal line 1202. When receiving unit 1210 sends the received packet to packet delay buffer 1230, packet detection circuit 1220 detects the transmission of the packet. The packet delay buffer 1230 has a preset maximum length area per packet. The packet output from the receiving unit 1210 is stored in the packet delay buffer 1230 by the packet length. When a packet is transmitted from the packet delay buffer 1230 to the OR circuit 780 or when it is not transmitted, the IDLE detection circuit 1250 detects whether such a packet is transmitted.

  The determination circuit 1240 determines whether or not to output the packet by the shaping unit 750 based on the detection result of the packet by the packet detection circuit 1220 and the detection result of the presence / absence of transmission of the packet by the IDLE detection circuit 1250. Specifically, when the transmission of the packet from the receiving unit 1210 to the packet delay buffer 1230 is not detected and the IDLE detection circuit 1250 does not detect the transmission of the packet from the packet delay buffer 1230 to the OR circuit 780, the determination circuit 1240 determines to transmit a packet from the shaping unit 750. When such a determination is made, the determination circuit 1240 sends a control signal (for example, the enable signal EN2 in the second embodiment) to the packet generator 720 of the shaping unit 750 so as to execute a packet transmission process. Send.

  On the other hand, when the above condition is not satisfied, or when the condition is not satisfied halfway when initially satisfied, the determination circuit 1240 determines that transmission of the packet transmitted by the shaping device 200 is started. For example, when a packet is transmitted from the packet delay buffer 1230 to the OR circuit 780 and the packet detection circuit 1220 detects transmission of a packet from the reception unit 1210, the determination circuit 1240 receives the signal from the shaping unit 750. The packet output from the shaping apparatus 200 is made to wait until the packet transmission is completed.

  As described above, according to the shaping device 1200 according to the third embodiment of the present invention, based on the presence / absence of a packet in the packet delay buffer 1230, transmission of packets from the cascade-connected shaping device 200, Switching between packet transmission from the own station, that is, the shaping unit 750, is performed. In this case, the shaping device 1200 does not require a circuit for transmitting a control signal to the shaping device 200, so the configuration of the shaping device 1200 does not become complicated. Moreover, the cascade joining of the shaping apparatuses 200 and 1200 can be easily realized.

<Fourth embodiment>
Hereinafter, a fourth embodiment of the present invention will be described. The shaping apparatus according to the present embodiment is different from the above-described embodiments in that it has a function of executing packet transmission from another shaping apparatus when no packet transmission is performed.

  With reference to FIG. 13, the structure of the shaping apparatus 1300 which concerns on this Embodiment is demonstrated. FIG. 13 is a block diagram showing a hardware configuration of shaping device 1300. The shaping apparatus 1300 includes a receiving unit 1210, an IDLE time measuring unit 1310, an OR circuit 1320, a cascade queue buffer 1330, a cascade / own station switching unit 1350, a gap information counter 1340, a shaping unit 750, and an OR circuit. 780 and a transmission buffer 260.

  The receiving unit 1210 receives an input of a packet transmitted by the shaping device 200 via a signal line. Receiving unit 1210 transmits the packet to OR circuit 1320. The IDLE time measuring unit 1310 measures the time during which no packet is transmitted based on whether or not the packet is transmitted from the receiving unit 1210 to the OR circuit 1320.

  Time information is input to the IDLE time measurement unit 1310. Cascade queue buffer 1330 includes a plurality of queue buffers. Each queue buffer has a preset capacity and stores a packet output from the receiving unit 1210 or gap information output from the IDLE time measuring unit 1310. In this case, storage in each queue buffer is executed according to a preset order. As will be described later, when data is read out from the transmission buffer 260, it is further stored in an empty area. Here, the gap information refers to information indicating a time when a packet is not output from the receiving unit 1210 based on a measurement result by the IDLE time measuring unit 1310. Such information is used for determination processing in the cascade / own station switching unit 1350.

  Time information is input to the gap information counter 1340. The gap information counter 1340 measures the presence / absence of gap information based on the information. A signal output from the gap information counter 1340 is input to the cascade / own station switching unit 1350.

  The cascade / own station switching unit 1350 generates a signal for switching the output of the packet from the cascade queue buffer 1330 or the output of the packet from the shaping unit 750 based on the information from the gap information counter 1340. For example, when information indicating that no gap exists is input from the gap information counter 1340 to the cascade / own station switching unit 1350, the cascade / own station switching unit 1350 may output a packet from the cascade queue buffer 1330. The enable signal EN1 is output to the cascade queue buffer 1330.

  On the other hand, when it is confirmed by the information from the gap information counter 1340 that no packet is stored in the cascade queue buffer 1330, the cascade / own station switching unit 1350 is enabled to execute the packet output from the shaping unit 750. A signal EN2 is generated and an enable signal EN2 is sent to the shaping unit 750. The enable signal EN2 is input to the timing generator 720. A control structure that defines these operations will be described later.

  Here, with reference to FIG. 14, a control structure of shaping apparatus 1300 according to the present embodiment will be described. FIG. 14 is a flowchart showing a procedure of processing executed by shaping device 1300.

  In step S1410, IDLE time measurement unit 1310 determines whether or not there is a packet input from a cascade-side device, that is, shaping device 200. If IDLE time measurement unit 1310 determines that such an input is present (YES in step S1410), the process proceeds to step S1420. If not (NO in step S1410), the process proceeds to step S1430.

  In step S1420, cascade queue buffer 1330 stores the packet output from OR circuit 1320 in any queue buffer. This storage is performed according to a preset order.

  In step S1430, IDLE time measurement unit 1310 measures idle time. Here, the idle time refers to a time during which no packet is output from the receiving unit 1210.

  In step S1440, IDLE time measuring unit 1310 determines whether or not a preset maximum time has elapsed. This determination is made by comparing the idle time measured by the IDLE time measuring unit 1310 with the maximum time stored in a memory (not shown). If IDLE time measurement unit 1310 determines that the maximum time has elapsed (YES in step S1440), the process proceeds to step S1450. If not (NO in step S1440), the process proceeds to step S1460. In step S1450, IDLE time measurement unit 1310 stores the maximum time as gap information in cascade queue buffer 1330.

  In step S1460, IDLE time measuring unit 1310 determines whether or not there is a packet input from receiving unit 1210 to OR circuit 1320. If IDLE time measurement unit 1310 determines that such a packet is input (YES in step S1460), the process proceeds to step S1470. If not (NO in step S1460), the process proceeds to step S1480. In step S1470, IDLE time measurement unit 1310 stores the measured idle time as gap information in any one of cascade queue buffers 1330.

  In step S1480, IDLE time measurement unit 1310 determines whether or not a predetermined time has elapsed. If IDLE time measurement unit 1310 determines that the predetermined time has elapsed (YES in step S1480), the process proceeds to step S1490. If not (NO in step S1480), the process returns to step S1430. In step S1490, IDLE time measurement unit 1310 stores the measured idle time as gap information in any region of cascade queue buffer 1330.

  With reference to FIG. 15, the control structure of shaping apparatus 1300 according to the present embodiment will be further described. FIG. 15 is a flowchart showing a procedure of processing executed by cascade / own station switching section 1350.

  In step S 1510, cascade / own station switching section 1350 receives gap information from gap information counter 1340. In step S1520, cascade / own station switching section 1350 determines whether or not the time corresponding to the gap information has elapsed. If cascade / own station switching unit 1350 determines that such a time has elapsed (YES in step S1520), the process proceeds to step S1530. If not (NO in step S1520), the process proceeds to step S1540.

  In step S1530, cascade / own station switching section 1350 sends a disenable signal as a CR signal to shaping unit 750. As a result, when the shaping unit 750 outputs a packet from the queue buffer 210, when the output of the packet is completed, the subsequent output is stopped.

  In step S1540, cascade / own station switching section 1350 sends an enable signal as a CR signal to shaping unit 750. Accordingly, when a packet is stored in the queue buffer 210, the timing generator 720 reads the packet from the queue buffer 210 and outputs the packet to the OR circuit 780.

  As described above, the shaping apparatus 1300 according to the present embodiment includes the cascade queue buffer 1330 that stores the buffers sent from the cascade-connected shaping apparatuses. The cascade / own station switching unit 1350 transmits the packet stored in the cascade queue buffer 1330 and transmits the packet stored in the shaping unit 750 based on whether or not the packet is transmitted to the cascade queue buffer 1330. Switch.

  In this way, since another shaping device, for example, the shaping device 200, can be connected to the shaping device 1300, the types of packets distributed from the transmission buffer 260 to the network 130, that is, the types of content can be increased.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure showing the information provision network containing the shaping apparatus 200 which concerns on the 1st Embodiment of this invention. 2 is a block diagram illustrating a hardware configuration of a shaping apparatus 200. FIG. It is a figure showing one mode of storage of data in queue buffer 210. 4 is a flowchart showing a procedure of processing executed by each hardware of the shaping apparatus 200. 5 is a flowchart showing a procedure of processing executed by timing generator 220. It is a figure showing the output mode of the packet input into the shaping apparatus. It is a block diagram showing the hardware constitutions of the shaping apparatus 700-1 which concerns on the 2nd Embodiment of this invention. 2 is a block diagram showing a hardware configuration of cascade / own station switching circuit 800. FIG. FIG. 3 is a diagram conceptually showing one mode of data storage in a memory 900. It is a timing chart showing the state of operation of each device when two shaping devices 700-1 and 700-2 are connected. It is a timing chart showing the signal output in order to stop each shaping function of shaping device 700-1 and 700-2 temporarily. It is a block diagram showing the hardware constitutions of the shaping apparatus 1200 which concerns on the 3rd Embodiment of this invention. It is a block diagram showing the hardware constitutions of the shaping apparatus 1300 which concerns on the 4th Embodiment of this invention. 10 is a flowchart showing a procedure of processing executed by shaping apparatus 1300. It is a flowchart showing the procedure of the process which the cascade / own station switching part 1350 performs.

Explanation of symbols

  10 content distribution system, 110 content DB, 120 video server, 130 network, 140 set top box, 142 buffer, 144 decoder, 150 television, 200, 700-1, 700-2, 1200, 1300 shaping device, 210 queue buffer, 220, 720 Timing generator, 230 counter, 240 frequency divider, 260 transmission buffer, 760, 1210 reception unit, 770 cascade gate, 780, 1320 OR circuit, 800, 1350 cascade / own station switching circuit, 810 input circuit, 820 Clock, 830, 1240 decision circuit, 840 output circuit, 900 memory, 1202 signal line, 1220 packet detection circuit, 1230 packet delay buffer, 1250 IDLE detection Circuit, 1310 IDLE time measuring unit, 1330 cascade queue buffer, 1340 gap information counter.

Claims (12)

Comprising stream input means for receiving a plurality of streams, each of the plurality of streams including a plurality of packets;
First storage means for storing each of the plurality of packets;
A plurality of generating means for generating signals for defining the timing for reading each of the plurality of packets based on the bit rate of each of the plurality of streams;
Control means for reading out packets of the stream corresponding to each signal from the first storage means based on each signal generated by each of the plurality of generating means;
Second storage means for storing packets read from the first storage means;
A variable-length frame shaping apparatus comprising: transmission means for transmitting a packet stored in the second storage means. Each of the plurality of generating means includes
Bit rate generating means for generating an equivalent bit rate of the plurality of streams;
The variable length frame shaping apparatus according to claim 1, further comprising: a signal generation unit configured to generate the signal based on the equivalent bit rate. Each of the plurality of generating means includes
An acquisition means for acquiring specific data for specifying the amount of data transmitted to the second storage means based on transmission of a packet from the first storage means to the second storage means;
2. The variable length frame shaping apparatus according to claim 1, further comprising timing signal generation means for generating the signal based on a bit rate of the stream and the specific data. The acquisition unit acquires the length of the packet stored in the first storage unit,
4. The variable length frame shaping according to claim 3, wherein the timing signal generation unit generates the signal by subtracting the packet length acquired by the acquisition unit based on a bit rate of the stream data. apparatus. The acquisition unit acquires a transmission byte of a packet transmitted from the first storage unit to the second storage unit,
4. The variable length frame shaping device according to claim 3, wherein the timing signal generation unit generates the signal by subtracting the transmission byte based on a bit rate of the stream. Input means for receiving an input of another packet output from another packet transmitting device;
2. The variable length frame shaping apparatus according to claim 1, further comprising switching control means for switching between transmission of the other packet and transmission of the read packet. The switching control means includes
Switching data storage means for storing first data for enabling transmission of packets by the transmission means and second data for enabling transmission of the other packets; The data and the second data are predetermined,
Based on the first data and the second data, a first control signal for reading the packet from the first storage means is transmitted to the control means, and the stream data is transmitted. The variable length frame shaping device according to claim 6, further comprising command means for exclusively outputting a second control signal for the packet transmission device to the packet transmission device. The switching control means further includes a time measuring means for measuring time,
The first data and the second data are respectively predetermined ratios for using a band for transmitting stream data,
The command means outputs the first control signal to the control means and the second control to the packet transmission device based on the time measured by the time measuring means and the predetermined ratios, respectively. The variable length frame shaping device according to claim 7, wherein the signal output is switched. The switching control means includes
Packet detection means for detecting the presence or absence of a packet based on a signal input via the input means;
Temporary storage means for temporarily storing packets from the other packet transmission device;
Idle detection means for detecting presence or absence of output of a packet from the temporary storage means;
Determining means for determining whether to output the packet stored in the first storage means based on the presence or absence of the packet and the presence or absence of the output of the packet;
Command means for sending the signal to the control means based on the result of the judgment by the judgment means;
The variable length frame shaping apparatus according to claim 6, wherein the control unit reads a packet stored in the first storage unit based on the signal. The switching control means includes
Idle measuring means for measuring idle time during which no packet is input to the input means;
Cascade storage means for storing the packet from the input means and the idle time;
Detecting means for detecting the passage of the idle time;
Command means for transmitting the signal to the control means so as to read out the packet until the idle time elapses;
A storage control means for storing a packet input via the input means in the cascade storage means when detecting an input of a packet to the input means before the idle time elapses;
The variable length frame shaping apparatus according to claim 6, further comprising: a reading unit that reads a packet stored in the cascade storage unit after the idle time has elapsed. The first storage means includes a queue buffer for temporarily storing each of the plurality of packets;
Each of the plurality of generating means includes
A frequency divider for generating a bit rate for each of the plurality of streams;
A plurality of counters that count down based on the bit rate generated by the frequency divider,
2. The variable length frame according to claim 1, wherein the control unit includes a controller that controls a timing of reading a packet stored in the queue buffer based on a signal output in accordance with each of the plurality of counters. Shaping device. An apparatus comprising storage means for electromagnetically storing data comprises receiving a plurality of streams, each of the plurality of streams including a plurality of packets,
Storing each of the plurality of packets in the storage means;
Generating a signal for defining a timing for reading each of the plurality of packets based on a bit rate of each of the plurality of streams;
Reading a packet of a stream corresponding to each of the signals from the storage means based on the generated signals;
And a step of transmitting a packet read from the storage means.

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