Source: https://patents.google.com/patent/DE69635934T2/en
Timestamp: 2020-01-20 10:33:06
Document Index: 736316296

Matched Legal Cases: ['art 1', 'art 1', 'art 207', 'art 207', 'art 207', 'art 207', 'art 207']

DE69635934T2 - Data transmission device, data receiving devices and data transmission control device - Google Patents
Data transmission device, data receiving devices and data transmission control device
DE69635934T2
DE69635934T2 DE69635934T DE69635934T DE69635934T2 DE 69635934 T2 DE69635934 T2 DE 69635934T2 DE 69635934 T DE69635934 T DE 69635934T DE 69635934 T DE69635934 T DE 69635934T DE 69635934 T2 DE69635934 T2 DE 69635934T2
DE69635934T
DE69635934D1 (en
Hiroyuki Katano-shi Iitsuka
Takuya Osaka-shi Nishimura
Hidetoshi Hirakata-shi Takeda
Masazumi Moriguchi Yamada
1995-04-28 Priority to JP10555495 priority Critical
1995-04-28 Priority to JP10555495A priority patent/JP3168873B2/en
1995-06-14 Priority to JP14720995 priority
1995-08-01 Priority to JP19634595 priority
2006-10-05 Publication of DE69635934T2 publication Critical patent/DE69635934T2/en
The The present invention relates to a transmission device for transmission video and audio signals between digital video and audio devices, the before the transfer captures part of a bandwidth of a transmission medium.
Currently comes the standardization of the bandwidth compression system for digital Video and audio progress well. The system is called MPEG (Moving Picture Experts Group) and will be released in two Divided groups, namely MPEG1 for storage media with lower Speed and MPEG2, which ensures high picture quality during transmission realized and can correspond to different image sizes. In MPEG2 can the data size per unit time for radio programs and contents changed be because the compression ratio for one Image size or a required image quality is variable.
In addition, will in MPEG2, the standardization also advanced for data transmission systems, which are used for sending. In these data transmission systems is a program called "power" and the Data size can changed in each stream become (variable speed). This is a system for simultaneous transmission several streams standardized. In particular, when a playback device for Playback of compressed video and audio signals with the broadcasting station, which performs the compression, must be isochronous, as when receiving radio waves the Case, a stream called "transport stream" becomes used. In this transport stream is a device, with which the reproducing apparatus with the aid of a parameter in Current can be isochronized. In the transport stream, the Transfer data in a fixed-length packet (hereinafter referred to as a transport stream packet) and the for needed isochronization Data will be transmitted with the same package type. This is in the source "Coding of moving picture and associated audio information. Part 1: System "(" Coding of moving pictures and associated Audio information. Part 1: System "), International Standard ISO / IEC 13818-1, International Technology.
At the Sending multiple streams if necessary, the data size per stream can also be changed, if the bandwidth of the entire transmission medium is constant is. The bandwidth of the specified transmission medium can be effective be used by a stream of high speed have to have a big one Bandwidth is assigned and the speeds of the others Currents kept low The bandwidth of the entire transmission medium is not for everyone Electricity split evenly becomes.
Becomes however, receive a broadcast signal and selected a certain stream and resent or recorded, so must be a bandwidth for sending or recording due to the maximum speed in the selected stream guaranteed become. For this purpose, a method is used in MPEG2, the a buffer for smoothing of a stream (hereinafter referred to as a smoothing buffer and the bandwidth used for sending or recording at a read rate from the smoothing buffer (hereinafter referred to as leak rate) is required. The memory size of the smoothing buffer and the leak rate are indicated by parameters contained in the stream.
at the procedure, the smoothing buffer and leak rate, the received current is immediately in one Smoothing buffer memory stored and read from there with the leak rate. As long as a smoothing buffer be used with a size expressed by a parameter in the stream and a leak rate is it going? Smoothing buffer memory not guaranteed over. Therefore, sending or recording resumes sending or Record by ensuring the bandwidth, which is equal to the leak rate, possible. Because by immediate Smooth the guarantee rate a bandwidth equal to the maximum rate (which is rare occurs), can use the bandwidth when sending or recording the stream different rates and the transmission or recording medium can be used effectively.
However, since the quality of the timing information of each transport stream packet is alleviated by immediately storing the stream in a smoothing buffer memory, the video and audio signal reproducing apparatus can not perform isochronization. Therefore, timing information written in the smoothing buffer memory is added to each packet in transmission and recording. In the Emp The reproducing apparatus reproduces the timing information by immediately storing each transport stream packet in a packet having the same size as the smoothing buffer memory and outputting the output signal based on the timing information added to each transport stream packet, thereby making it possible to obtain the timing information Isochronization in the playback device for video and audio signals to perform.
Around So to send an MPEG2 transport stream, it must be possible the timing of each transport stream packet in the receiving device of the transport stream package. A transmission medium that the Timing control is the interface P1394. P1394 is a high-speed serial interface for multimedia the next Generation that is being studied at the IEEE. It is in the source "High Performance Serial Bus P1394 / Draft 7.1v1 "(" Serial High performance bus P1394 / draft 7.1v1 ").
P1394 is a serial bus type transmission medium, and all nodes connected to a bus have isochronized Time control information. When sending an MPEG2 transport stream packet The timing of each transport stream packet will be using the timing information saved.
A Device connected to P1394 (hereinafter referred to as node is connected in a tree structure with branches, and a node with multiple connections sends the signal by issuing a signal received from one of the ports Signal to another terminal. This ensures that it arrives at each node, with the output from a node Data is connected. Therefore, P1394 theoretically works as a bus, although he has a tree structure.
There however P1394 realized a bus by relay control of several nodes, there is a delay, which depends on the number of relay nodes, and a propagation delay, the of the length of the transmission medium is determined. Furthermore At P1394, it is ensured that not several nodes are concurrent send by assigning buses to only one node.
Therefore receives every node for a bus has an identifier for identifying the node (hereafter referred to as node identifier). The assignment of the node identifier is done automatically by initializing a bus that generates is when the bus receives a new node or if a node disconnected from the bus (hereinafter referred to as bus reset). If a bus reset is generated, gives a node connected to the bus in a certain Sequence a packet to the bus that indicates the connection state of the node (hereinafter referred to as self-identification packet). The node identifier is determined by the output order of the self-identification packet determined, and the self-identification package contains the Outputting the node identifier set to the self-identification packet and information about it, whether the other nodes are connected to the individual ports or not. As far as the node in the bus is concerned, the tree structure forming the bus can by receiving and analyzing all output from each node Self-identification packets are determined.
at P1394 are two types of transmission possible, namely an isochronous transmission, those for transfer is used by data that requires real time, such as an MPEG2 transport stream or a digital video signal, and an asynchronous transmission for outputting is used by data that does not require real time. P1394 works based on a 125 microsecond period (hereafter referred to as Cycle and becomes isochronous transfer after the first half the period and asynchronous transmission after the second half used.
at an isochronization transfer will the during needed a cycle Time (bandwidth) in the node detects the bandwidths the transmission controls. P1394 has a node that is at isochronous transmission controls the bandwidth used, and the bandwidth to use is detected by the bandwidth control node. The node to carry out the isochronous transmission can transmit the data in the range of the detected bandwidth, and by isochronous transfer data sent is output as a packet specified by P1394. In an isochronous transmission can be real-time data by saving the transmission the data size determined in each cycle.
The bandwidth to be detected before the transmission consists of several bandwidths, such as. A bandwidth required to transmit the data in practice, and a bandwidth needed to transmit the data added because of the propagation delay that arises in data transmission and error detection. For P1394, a mixture of several transmiss tion speeds and output signals that control their transmission rates for identification before packet transmission.
In addition, will currently except MPEG2 also a digital VCR for converting video and audio signals into digital signals and to record these digital signals developed. This digital VCR system becomes a digital video signal compressed and recorded on a tape. Method for signal compression for a high resolution television picture (HD TV picture) and for a standard definition TV picture (SD TV picture) are also being developed. The compressed Data size of one HD video signal is twice that of an SD video signal and all data is compressed so that it is a fixed one Have speed that differs from MPEG.
There the digital VCR signal is a compressed signal when it is transmitted will, after getting into an analog video signal and then again has been converted into a digital signal, it comes to a deterioration the picture quality. Therefore, it is appropriate to a digital VCR signal as a digital signal to transmit, with P1394 for transmission can be used by digital VCR data.
at However, in P1394, each node connected to a bus has a virtual one Address space, and asynchronous data transfer between nodes is done by reading and writing the address space. In one part of the address space is a register used to control the Operation of each node serves. In one connected to a bus Node can be the node state by reading from a control register of a other node can be determined and vice versa, the node through Describe the control register to be controlled.
The Sending and receiving the isochronous data should be done with the help of a controlled such control register. In this case, the transmission or receiving state by reading a register for isochronous transfer control be determined. It is also possible, Start and end of sending or receiving isochronous data by writing the required value to the register.
If transmit an MPEG2 transport stream with a transmission medium will after a bandwidth has been detected as before at P1394 is, it is assumed that the data speed changes on the transmission path and those for transfer needed Bandwidth greater than the bandwidth already recorded is. An example of this is the Case that the leak rate is due to a change in a program during transmission greatly increased. On the other hand, if digital VCR data is being transmitted, it is assumed that that the signal is during the transmission converted from an SD video signal into an HD video signal. An example therefor is the case that recorded an SD video signal up to half of the tape and then the recorded signal into an HD video signal transformed. When the tape is played, the signal changes SD video data into HD video data and data size doubled yourself. So if the data speed changes, the transmission can with a bigger than the previously recorded bandwidth.
When For example, let me mention a case where P1394 in a transmission medium is used. When an MPEG2 transport stream is output to P1394 becomes due to a leak rate issued prior to transmission of the stream detects and outputs a bandwidth. If, however, the leak rate during the transmission greatly increased, so the bandwidth required to output becomes greater than the bandwidth already recorded and there could be a risk that more data is output to a bus than the one previously covered bandwidth. However, if the signal from converted an SD video signal into an HD video signal and the Data size doubled, There is a risk that twice as much data is output to the bus will be like those that match the previously detected bandwidth.
If at P1394, more data than the data that was previously acquired bandwidth to be sent to a bus is the time to transfer the data needed that will be during a single cycle for transmit the isochronous transmission Need to become, longer as the for fixed the isochronous transmission and assigned time. In case of such a bandwidth violation is not an asynchronous transfer possible, there the time for the asynchronous transmission too short. If the for the isochronous data transmission required time longer than 125 microseconds, the bus can no longer work, and not just the data that causes it, but all the others as well isochronous data that is on the bus can not be forwarded and to be received.
As explained above, when a transmission medium that detects a part of a bandwidth of the transmission medium before transmission is used and the transmission is at a larger band The problem is that the other transmissions using the same transmission medium are disturbed.
on the other hand could the device that transfers the data over a transmission medium receives receive erroneous data when the speed of the transmitted Data increased. A first example is the case that the leak rate increases when an MPEG2 transport stream from a transmission medium is received and video and audio signals from the received data be reproduced or the transport stream is recorded. A second example is the case where the digital VCR data from SD video data into HD video data when the digital VCR data from the transmission medium received and video and audio signals from the received Data is reproduced or recorded. As for the data transmission required bandwidth greater than in the transmission medium detected bandwidth, the transmitting device, the normal transmission do not resume, so erroneous data is sent to the transmission medium can be sent.
Become during playback or recording of a transport stream or of VCR data, the received in the receiving device, a faulty transport stream or faulty digital VCR data will receive or go the received one Data can be lost erroneous data is reproduced or recorded. In addition, can in the case that the receiving device is in operation and the Synchronization with a synchronization signal contained in the received data takes place, the isochronization is lost and a disturbance occurs.
If Data from a transmission medium be received, which is part of the bandwidth of the transmission medium before the transfer captured and the transmission performs, and if that for data transfer required bandwidth greater than is the previously detected bandwidth in the transmission medium, so could faulty data to the transmission medium be sent, and if the erroneous data to the transmission medium are sent causes the device receiving this data a disorder, which is problematic.
on the other hand could as with P1394, when the transmission after detecting part of the transmission medium bandwidth before the transfer the other devices start to output the data, the transmission already started abort and use the bandwidth used in the aborted transmission has been used.
One Example is the case that a second device is the data output tries to start while a first device outputs data to the transmission medium. When a bandwidth in which the second device outputs the data can, in the transmission medium remains, the second device, after detecting the bandwidth start with the output. If, however, the required bandwidth does not remain there, can not be started with the transfer. Thus, the transmission to be started only after the second device has the output required bandwidth guaranteed has, so that the first device stops the output.
In this case must be with the transfer are started after the control node uses the bandwidth used reset and has re-captured it. Since the bandwidth needs to be captured, after being reset has been confirmed by the bandwidth detection device the resetting of the Bandwidth has ended and must follow the reset process. Because of the reset the bandwidth passes until their re-capture time passes Furthermore the risk of another node detecting the bandwidth. It exists So the problem is that the process required to capture the bandwidth difficult.
If a propagation delay takes place, which as with P1394 of the connection form of with the transmission medium dependent node, It is necessary to record a bandwidth other than the actual transmission required bandwidth more information such as propagation delay time includes.
In this case, the bandwidth can be detected due to the maximum propagation delay time. However, if the bandwidth to be detected is determined on the basis of an assumed maximum propagation delay time, the transmission medium can not be used effectively because additional bandwidth is detected that is not actually required and therefore there is a risk that the other transmissions that are originally performed can, are not possible. So if the bandwidth is detected due to the maximum propagation delay, there is the problem that the transmission medium is not can be used effectively.
If in a normal transmitting device, information about smoothing buffer memory and leakage rate are included in the data, the data must be analyzed and the speed information is extracted to the transmission bandwidth or to determine the recording mode, and there is the disadvantage that the hardware when recording with the receiving device is extensive becomes.
If the buffer on the side of the receiving device overflows or is underutilized, the data transfer is impossible and can not usually be controlled at the transmitting device.
The Document W0-A-95.03658 describes a bus management system which with a channel occupation register REG1 and a bus capacity register (Bandwidth Register) REG2 is provided. Before the beginning of the synchronous transmission Each node sends a read command to the registers for their contents to read and put them on available channels and bus capacity to consider. If an unused channel and a free bus capacity available the node sends a write command to the registers so that the number of occupied channels and the capacity the buses used are stored in the registers REG1 and REG2, respectively can be. Thus, you can Buses are managed in a system with a simple method, the one synchronous transmission under several nodes connected to the buses. The Bus management system reserves the bandwidth without consideration the propagation delay.
The Document EP-A-0,637,153 describes a method and an apparatus for the automatic splitting of a packet-switched network in Backbone nodes and subrange nodes to increase the speed of the To increase the route, without affecting the optimization criterion of the routing algorithm and additional Generate control messages in the network.
directed EP-A-0511786, which is the precharacterizing features of the present invention Invention describes.
1 FIG. 12 is a block diagram of important portions of a data transmission transmitting apparatus and a received data receiving receiving apparatus useful for understanding the present invention.
2 shows a packet used in the transmission of data by isochronous P1394 transmission, which is not part of the present invention.
3 FIG. 12 shows the field structure of a CIP header of a packet included in a data field used in P1394 isochronous transmission not part of the present invention. FIG.
4 FIG. 12 is a block diagram of key components of a transmitting apparatus for transmitting isochronization data according to an exemplary embodiment of the present invention.
5 Figure 12 shows the bandwidth that must be detected when transmitting P1394 isochronization data, according to an exemplary embodiment of the present invention.
6 FIG. 12 shows a connection of nodes separated by (N-1) relay nodes in N time connections, according to an exemplary embodiment of the present invention. FIG.
7 shows the construction of the PCR (Plug Control Register), a register for controlling the transfer of isochronization data according to an exemplary embodiment of the present invention.
8th FIG. 12 is a block diagram of essential components of two transmitters in the case where the isochronization data transmit nodes are connected, according to an exemplary embodiment of the present invention.
9 FIG. 12 is a block diagram of key components of a transmission control apparatus for determining and setting a propagation delay identifier and essential components of a transmission apparatus in which the propagation delay identifier is set according to an exemplary embodiment of the present invention.
10 Fig. 10 is a block diagram of a first example bandwidth detection means according to an exemplary embodiment of the present invention.
11 Fig. 10 is a block diagram of a second example bandwidth detection means according to an exemplary embodiment of the present invention.
12 Figure 10 is a block diagram for data processing means according to an exemplary embodiment of the present invention.
13 FIG. 10 is a block diagram of a transmission timer according to an exemplary embodiment of the present invention. FIG.
14 shows the structure of a transmission timestamp according to an exemplary embodiment of the present invention.
preferred embodiments The present invention will be described below with reference to FIG the drawings explained.
A first exemplary embodiment of the present invention is in 1 shown. In the first exemplary embodiment, a transmitting device 124 to send data 108 to a transmission medium 114 Following:
Data processing means 130 for processing, for. For converting data to be sent 108 in a transmission format by dividing or connecting; Bandwidth detection means 101 for determining the bandwidth of the data 108 ; Necessary bandwidth calculation means 102 to calculate the required bandwidth in the transmission medium 114 from the bandwidth detection means 101 determined data bandwidth 109 ; Transmission condition judge means 103 for comparing the required bandwidth calculating means 102 calculated required bandwidth 110 with the detected bandwidth 104 that is captured from the bandwidth that the transmission medium 114 has, before the transmission, judged the transmission state and output a judgment result 111 ; Transmission control means 105 for inputting the judgment result and for outputting the data from the data processing means 130 as data 112 are output, which are to be sent according to the judgment result; Bandwidth information adding 106 for adding the bandwidth detection means 101 output data bandwidth 109 to those of the transmission control means 105 data output as bandwidth information 112 and to output the data; and transmission means 107 to send data 113 to which the of the Bandwidth Information Supplements 106 output bandwidth information has been added to the transmission medium 114 , The sending device 124 is part of a receiver for digital TV radio signals or digital VCR signals, and that in the transmitting device 124 entered data 108 are data attached to a tuner 126 or data received in a playback device 127 be reproduced. As data 108 For example, signals such as an MPEG2 transport stream or data of a digital VCR signal are input.
A receiving device 125 for receiving data from the sending device 124 over the transmission medium 114 are output, comprises receiving means 115 for receiving data from the transmission medium 114 and to spend; Transmission stop detection means 116 for inputting to the receiving means 115 received data 119 to recognize that certain time data does not arrive, and to output a recognition result 120 ; Bandwidth information separation means 117 for entering the at the receiving means 115 received data 119 with added bandwidth information and for separating and outputting the bandwidth information 121 ; and processing means 118 for inputting from the transmission end detection means 116 output recognition result 120 , to enter the bandwidth information 121 from the bandwidth information separation means 117 and for processing the corresponding inputs. The receiving device 125 is part of a digital VCR or television receiver, and the data received 122 be in one Device, such as a recording device 128 or a playback device 129 , entered.
As a transmission medium 114 , which is used to send and receive digital video and audio data, a P1394 interface can be used.
If data 108 in the sending device 124 are an MPEG2 transport stream coming from the tuner 126 or from the playback device 127 is input, so before the transmission, the required bandwidth for outputting to the transmission medium 114 calculated and detected from a parameter indicating the leak rate contained in the transport stream. For P1394, the receiving device 125 containing the data from the transmission medium 114 and the other receiving devices connected to the same bus, as well as the transmitting device 124 detect the bandwidth and the bandwidth used for data transmission is detected by a node to control the bandwidth. If the device for detecting the bandwidth, a device other than the transmitting device 124 is, the leakage rate of the current before for the transmitting device 124 polled, the required bandwidth is detected from the leak rate obtained as a result, and the transmission becomes for the transmitting device 124 requested. The query of the leak rate or the direction of transmission can be done by asynchronous transmission using the same bus. The bandwidth to be detected here indicates the time required for data transmission in one cycle, and is the bandwidth required to generate a packet in the later-described transmission to P1394 and added to the bandwidth indicating the leak rate ,
While the transmitting device 124 sends a transport stream, recognizes the bandwidth detection means 101 a leak rate contained in the transport stream and give it as bandwidth data 109 the to the transmission medium 114 output data. In the same manner as in the detection of the bandwidth before the start of the transmission, the required bandwidth calculating means calculate 102 that the bandwidth data 109 that of the bandwidth detection means 101 sent data, the current used when outputting to P1394, and give it as required bandwidth 110 by optionally adding the bandwidth data to the packet to generate a packet at leak rate.
The transmission state judging means 103 hold a bandwidth detected before transmission 104 , compare with the required bandwidth 110 that are required by the bandwidth bandwidth calculator 102 be entered, and give it as an evaluation result 111 out. The transmission control means 105 that the assessment result 111 enter, enter one into the transmitting device 124 entered transport stream, if the judgment result 111 shows that the required bandwidth 110 less than the detected bandwidth 104 is because it is assumed that the transmission can be continued easily, and on the other hand, the transmission device 124 entered current cleared when the judgment result 111 shows that the required bandwidth 110 greater than the detected bandwidth 104 because continued transmission might prevent other isochronous or asynchronous transmissions.
In the Bandwidth Information Additive 106 is from the transmission control means 105 a transport stream 112 entered, and they add the bandwidth data 109 which are the data from the bandwidth detection means 101 are entered as bandwidth information and output it. At this time, the transmission control means terminate 105 the output of the transport stream and output only the bandwidth information. The sending means 107 that the transport stream 112 and the bandwidth information 109 enter, generate from the transport stream 112 a packet and send it to the transmission medium 114 , The structure of a packet for isochronous P1394 transmission is in 2 shown.
The packet used when the digital video and audio data is transmitted using P1394 consists of a packet header 201 , which is used to distinguish the types of packages, a CRC (Cyclic Redundancy Check) 202 for the packet header, which is added to detect errors in the packet header during signal reception, a payload part 207 and a CRC 205 for the data added for error detection in the payload part. The payload part 207 consists of a CIP header 206 (CIP = Common Isochronous Packet), which is used to add the data type or the bandwidth information, and multiple data blocks 204 with video and audio data. The data 108 in the sending device 124 are called a source packet and sent as a fixed-size data block, being unchanged or shared in a part of the payload part 207 are included.
The CIP head 206 consists of 4-byte data 203a with a parameter for the data transfer method and 4-byte data 203b with data types and a parameter required for each type. The exact structure of the CIP head 206 is in 3 shown. The CIP header consists of a SID (Source Node Identification Number). 301 which is an identifier for recognizing the node sending the data; a DBS (Data Block Size) 302 indicating the data block size; an FN (Fraction Number) 303 indicating how the source packet was shared or that it was not shared to produce a data block; a QPC (Quadlet Padding Count) 304 indicating the number of bytes input to the source packet to set the source packet size and to perform the division; an SPH (Source Packet Header) 305 indicating whether or not the source packet has a header based on the data types; a DBC (Data Block Continuity Counter) 306 a counter for confirming the continuity of the data block; an FMT (format) 307 indicating the types of data sent; and an FDF (Format Dependent Field; 308 with the parameters required for each type of data.
If the transmitting means 107 send a transport stream to P1394 is from FMT 307 indicated that the signal is an MPEG2 transport stream and that the bandwidth information indicating the leak rate is part of the FDF 308 be sent. As with the other fields, the CIP head has 206 an appropriate value and is output as an isochronous transmission packet. If in this case the data, the transmitting means 107 from the Bandwidth Information Additive 106 receive, is a transport stream, a data block is generated from the transport stream, and a parameter indicating the leak rate becomes part of the FDF 308 transfer. If, on the other hand, those from the Bandwidth Information Additives 106 When data provided is only bandwidth information, a parameter indicating the leak rate becomes part of the FDF 308 introduced and only the CIP head is called payload part 207 transmitted because no transport stream is to be transmitted.
So if the bandwidth of the sending device 124 entered transport stream is greater than the previously detected bandwidth 104 is, the transport stream output can be aborted, and it can be avoided that the further isochronous and asynchronous transmission to the other devices using the same bus is disturbed. Since the packet is always transmitted only with the CIP header, even if the data is not transmitted, the receiving device that has received the packet can perform corresponding processing. If it is a packet that does not contain a transport stream, the detection information of the sending device becomes the SID 301 introduced, and to the FMT 307 and the FDF 308 For example, the information indicating that the data to be transmitted is an MPEG2 transport stream and the parameter indicating the leak rate of the stream are sent.
In the receiving device 125 however, that is a packet from the transmission medium 114 receives, receive the receiving means 115 a packet for isochronous transmission of P1394 after confirmation of the packet header, and the data 119 with the added bandwidth information is output after confirming the continuity of the data block using the CIP header. The transmission end detection means 116 that the data 119 have received, based on the information indicating that the transport stream has not arrived, that the sending device 124 the transmission has stopped, and give a recognition result 120 out. Since in the MPEG2 transport stream the maximum interval among the transport stream packets contained in the stream is determined, if the transport stream is not received beyond this maximum interval, it can be assumed that the transmitting device 124 the transmission has stopped. It can be noted that even if the transport stream is not received, the transmission medium is functioning properly because the packet containing only the CIP header is received. However, if the packet is not received at all, it can be assumed that either the transmission medium or the transmitting device 124 not working properly.
The bandwidth information separation means 117 get the data to which the bandwidth information is added by the receiving means 115 provided, separate them into bandwidth information 121 and dates 122 and spend them separately. If that of the receiving means 115 provided data is only bandwidth information, the bandwidth information 121 output. The transport stream in the data 122 contained by the Bandwidth Information Separators 117 are outputted to the recording device 128 recorded or on the playback device 129 played back as video and audio signals.
The processing agents 118 process the data based on the recognition result 120 based on the transmission end detection means 116 and that of the bandwidth information separating means 117 provided bandwidth information 121 , If the recognition result 120 , which is the transmitting end of the transmitting device 124 is input, enter the processing means 118 the command to terminate the operations, since neither the recording device 128 the recording can properly perform, nor the playback device 129 normal playback.
When from the transmission medium 114 no effective transport stream is provided, since there is neither data for recording or reproduction, nor isochronization information contained in the transport stream, the isochronization of the receiving device is disturbed and failure can occur. When the transmitting device 124 the output of the transport stream terminates, give the processing means 118 the command to terminate the recording and reproducing operations and worthless recording and reproducing operations as well as failure can be avoided.
The processing agents 118 get the bandwidth information 121 from the bandwidth information separation means 117 and monitor the leak rate of the transport stream on receipt. The recording device 128 , which records the transport stream, can determine the speed of recording due to the leak rate of the transport stream. Although the recording is made during the reception of the transport stream, it becomes erroneous when the leak rate of the transport stream at reception is larger than the recording speed. Therefore, the processing agents give 118 a signal 123 with the recording command to the recording device 128 and they can thus perform the recording operation by stopping recording or changing the recording speed in the recording apparatus 128 continue.
Even with a package that contains no transport stream, since the recognition information of the transmitting device 124 can be obtained from the SID value contained in the CIP header, the transmitting device 124 instructed to stop the transmission. If the device, the bandwidth of the transmission medium 114 has detected the receiving device 125 is and the transmitting device 124 Due to the fact that the leak rate changes and the required bandwidth is greater than the detected bandwidth, the transmission aborts, the receiving device 125 detect a bad bandwidth, and the transmitting device 124 can start sending again.
If the data 108 in the sending device 124 are input, digital VCR data are from the playback device 127 are provided, which is for transmission to the transmission medium 114 Required bandwidth before transmission is calculated and detected, depending on whether the video signal is an SD or an HD video signal.
There the digital VCR data is data at a fixed speed, The bandwidth can be determined by the type of video signal. As with the MPEG2 transport stream, not only the sending device, but you can also the other devices capture the bandwidth. In this Case, the type of the transmitted video signal is queried beforehand.
When the transmitting device 124 the digital VCR data transmits, recognizes the bandwidth detection means 101 Whether the video signal is an SD or HD video signal, and give the bandwidth information 109 off, which is for outputting to the transmission medium 114 needed. The required bandwidth calculating means 102 containing the bandwidth information 109 received the transmission data from the bandwidth detection means 101 Similarly to the detection of the bandwidth before start of transmission, the bandwidth required to generate a packet in transmission is added to the data bandwidth, and the bandwidth actually used in outputting the data to P1394 is added calculated and required bandwidth 110 output.
The transmission state judging means 183 keep track of the bandwidth detected before transmission 104 , compare with the required bandwidth 110 that are required by the bandwidth bandwidth calculator 102 is provided and give the judgment result 111 out. Since it is assumed that there are no problems with the continuation of the transmission when the judgment result 111 smaller than the occupied bandwidth 104 is give the transmission control means 105 that the assessment result 111 Enter the digital VCR data coming out into the sending device 124 were entered. However, as a continuation of the transmission could prevent another isochronous or asynchronous transmission if the required bandwidth 110 greater than the detected bandwidth 104 , delete the transmission control means 105 into the sending device 124 entered data.
The Bandwidth Information Additive 106 give the digital VCR data from the transmission control means 105 a, add the bandwidth information, which is the data from the Bandwidth detection means 101 are provided as bandwidth information and output it. In this case, if the transmission control means 105 cancel the data output, they output only bandwidth information. From the transmission means 107 input the digital VCR data and the bandwidth information obtained from the bandwidth information adding means 106 are provided, a packet is generated which is sent to the transmission medium 114 is issued.
The isochronous transfer packet used at P1394 has the same structure as a packet used to transmit an MPEG2 transport stream. If the transmitting means 107 Digital VCR data sent to P1394 is from the FMT 307 indicated that it is digital VCR data, and the information indicating whether the video signal is an SD or an HD video signal are considered part of the FDF 308 transfer. Since the digital VCR data has a fixed speed, it has the same effect as expressing the data bandwidth by the recognition information indicating whether it is an SD or HD video signal. As with the other fields, the CIP header exists 206 from a corresponding value and is transmitted as a packet for isochronous transmission. When doing this at the receiving means 107 that from the bandwidth information add-ons 106 data received with the added bandwidth information, a data block is generated from the digital VCR data, and the parameter indicating the type of the video signal becomes part of the FDF 308 transfer. However, if those of the bandwidth information add-ons 106 If data received is bandwidth information only, the parameter indicating the type of video signal will become part of the FDF 308 introduced, and only the CIP head is called payload part 207 because there is no data to be transmitted.
Because in the sending device 124 If the input digital VCR data has been converted from SD to HD video data, the transmission of the digital VCR data may be aborted, and interference with continuation of isochronous or asynchronous transmission of other devices using the same bus may be avoided if the bandwidth required for the transmission is greater than the previously detected bandwidth 104 becomes. Since, as in the transport stream transmission, the packet is always transmitted only with the CIP header, the receiving device receiving this packet can perform the processing accordingly. Even if it is a packet containing no data, the recognition information of the transmitting device indicating that the data to be transmitted is digital VCR data and the information indicating whether the data is SD or HD video data are, in the SID 301 included and will be sent to FMT 307 and FDF 308 Posted.
In the receiving device, which is a packet from the transmission medium 114 receives, after confirmation of a packet header, the transmission means 115 a packet for isochronous transmission of P1394 and provide the digital VCR data 119 to which bandwidth information has been added after confirming the continuity of the data block, using the CIP header. The transmission end detection means 116 that the data 119 receive, recognize that the transmitting device 124 the transmission has stopped because the data has not arrived for a predetermined period of time, and give the recognition result 120 out. As with receiving a transport stream, it can be determined that the transmission medium is functioning properly even if the data is not received for a while because a packet containing only the CIP header is received. If, on the other hand, the packet is not received at all, it is to be assumed that the transmission medium or the transmitting device 124 not working properly.
The bandwidth information separation means 117 receive data with added bandwidth information from the receiving means 115 , separate them into bandwidth information 121 and dates 122 and spend them separately. If that of the receiving means 115 received data only bandwidth information, only the bandwidth information 121 output. The digital VCR data provided by the bandwidth information separation means 117 are output to the recording device 128 recorded or on the playback device 129 played back as video and audio signals.
The processing agents 118 process the data received by the transmission end detection means 116 provided recognition result 120 and that of the Bandwidth Information Separators 117 provided bandwidth information 121 , If the recognition result 120 that the transmitting device 124 instructs to terminate the transmission, since neither the recording device 128 the recording can properly perform, nor the playback device 129 normal reproduction can be given by the processing means 118 close the command to perform these operations.
If no usable digital VCR data is received from the transmission medium, since not only is there no data to be recorded or reproduced, but also the isochronization information transmitted along with the data is not received, the receiving device could lose isochronization, and it could come to the failure. When the transmitting device 124 the transmission of data stops, give the processing means 118 the command to stop recording and playback, and worthless recording and playback operations as well as failure can be avoided.
The processing agents 118 give the bandwidth information 121 from the bandwidth information separation means 117 and track what type of digital VCR data the received signal is from. The recording speed of the recording apparatus 128 must be determined depending on the type of digital VCR data. If the digital VCR data changes from SD to HD video signal or vice versa when recording the received data, proper recording becomes impossible. The recording can be continued by the recording device 128 instructed to stop recording or to change the recording speed.
Also, if it is a packet that does not contain digital VCR data because the recognition information of the sending device 124 can be obtained from the SID value contained in the CIP header completes the receiving device 125 an insufficient bandwidth, and so can the sending device 124 start transmitting again when the transmitting device 124 has been instructed to abort the transmission, or if the device is the bandwidth of the transmission medium 114 detected, the receiving device 125 is and the data type changes and the sending device 124 has terminated the transmission due to the required bandwidth being greater than the detected bandwidth.
It is believed that the bandwidth required for this transmission changes when the transmission data is converted from an MPEG2 transport stream to digital VCR data, or vice versa. Even if this data type changes, the transmitting device 124 start transmission again by comparing the bandwidth required during transmission with the bandwidth detected by the transmission medium and assessing the transmission state.
Because the receiving device 125 can determine the type of data from the CIP header contained in the receiving packet, it can use the recording method of the recording device 128 change if the receive data is converted from an MPEG2 transport stream to digital VCR data or vice versa, or it may abort the recording if the newly received data can not be recorded. In this case, playback can be stopped when a corresponding playback method is selected or the newly received data can not be played back. When the device giving the command for data transmission, the receiving device 125 is and the transmission does not need to be continued because the received data can not be recorded or reproduced, the transmitting device 124 instructed to stop the transmission.
Even if no bandwidth information adding means 106 and bandwidth information separation means 117 are present prevents the transmitting device 124 transmission beyond the detected bandwidth, and interference with continued isochronous and asynchronous transmission other than transmission, the same transmission medium 114 used can be avoided. The receiving device 125 detects the end of the transmission from the transmitting device 124 , stops recording and playback and can avoid a failure.
below the structure of the bandwidth detection means and the data processing means will be described.
10 shows a first example of a block diagram of the bandwidth detection means.
The bandwidth detection means 101 consist of an information table holder 1 and a transmission speed information extractor 2 ,
The inputted MPEG2 transport stream packet header is analyzed, and information tables such as a program directory table (PMT) and an event information table (EIT) are extracted and stored in the information table holder 1 held. In these tables, program names, transmission times, speed information, etc. are written.
Information about the transmission rate, for example the smoothing buffer keyword in the PMT, is in the transmission rate information extractor 2 extracted. The transmission bandwidth is calculated using the required bandwidth calculation means 102 extracted information is determined.
11 shows a second example of a block diagram of the bandwidth detection means. It is used when the MPEG2 transport stream packet has no transmission speed information or when the analysis load of the data is to be reduced. block 3 is a counter and block 4 a bandwidth determiner in the bandwidth detection means 101 from 11 ,
The counter 3 counts consecutively the data sizes (in this case the number of data packets) that are sent to the sender during a defined period of time, eg. For example, a period of 24.576 MHz, the IEEE 1394 clock, may be entered. Since the data packet size is a fixed number, ie 188 bytes in MPEG2 transmission, it is comparatively easy to determine the average speed.
The bandwidth determiner 4 The average speed for each period can be out of range with the counter 3 determine the counted value. The average speed is selected from several transmissible bandwidths that the transmitter has. In determining the transmission bandwidth, the transmission bandwidth determiner 5 selects the smallest transmission bandwidth considering a speed larger than that at the bandwidth determiner by a certain amount 4 Average speed determined is (for example, 1.2 times) and is in a range in which the jitter can be absorbed due to, for example, the deviation in the data arrival time. In order to ensure the selected transmission bandwidth, a transmission packet containing bandwidth guarantee request information is sent to the transmission medium.
The Data speed can be directly through the aforementioned operation without analysis in the MPEG2 signal, and the transmission bandwidth can be easily determined using the result. The information about the determined data speed can be determined by retransmission to the table.
12 shows a block diagram of the data processing means. In the data processing means 130 is the block 21 a smoothing buffer, the block 22 an arrival time keeper, the block 23 a timestamp generator, the block 24 a timestamp addressee, the block 25 a transmission timer, the block 26 a cycle time register (CTR) and the block 27 a transmission packet converter.
The timestamp of the transmission is based on the count of the CTR 26 which is a timer that sets the time for the devices connected to the transmission medium. The arrival time at which the individual MPEG2 transport stream packets from the tuner 126 be provided or the data of the playback device 127 For example, output from an MPEG2 decoder box to the transmitting device is detected in the arrival time 22 detected. The timestamp generator 23 saves the value of the CTR 26 at the time of arrival in the latch and generates the transmission time stamp, adding the count of the maximum delay time between the designated transmitting device and the designated receiving device. The transmission time stamp is added in the data block above. An example of the format is in 14 shown.
The entered transport stream packet is provided with the transmission time stamp and is stored in the smoothing buffer after storage 21 in the timestamp addressee 24 converted into a data block. Then it will be in the transmission packet converter 27 converted into a transmission packet in which several data blocks unite. After dividing into blocks of data such as speed, the transmission packet is occasionally converted.
13 shows a block diagram of the transmission timer 25 , block 30 is an output time judging unit, block 31 is a counter and block 32 is a transmission time control device. The time in which the actual transmission from the transmission packet converter 27 takes place to the transmission medium is in the transmission timer 25 controlled.
The output time judging unit 30 receives the timestamp values that the output time at the receiver of the individual data packets from the timestamp generator 23 indicates, holds and then compares them one at a time with the current CTR value and judges whether the data packet has already been issued by the receiver.
The CTR values of the receiving device and the transmitting device are the same, since they are set to face each other Nodes to which they are connected are the same. Therefore it is enough for the the above assessment, if only two values compared become.
The counter 31 performs a countdown by one for each data packet and it will result from the transmission packet converter every time a data packet is sent 27 a count-up by one when the output time judging unit 30 decides that the issue has already been made. That is, the count becomes equal to the number of data packets in the buffer of the current receiver. The transmission time control device 32 outputs a signal at the time of the output from the transmission packet converter 27 according to the output from the meter 31 to control. That is, as the count increases and exceeds almost a fixed value (the buffer size / data packet size ratio), the output from the transmit packet converter becomes 27 delayed to the transmitting means. However, when the count approaches zero, the output from the transmit packet converter becomes 27 accelerated to the transmitting means. The control unit 32 may consist of a microcomputer and software according to the aforementioned concept.
In the above method, the transmission timer 25 be controlled in the transmitting device so that the receiving device side buffer neither overflow nor is under-utilized. The receiving device may, for example, output to the recording device a signal with an error-free time without the buffer overflowing in the receiving device, by outputting the signal with a time specified in the transmission time stamp. The count value is controlled so as to be as large as possible within a range not exceeding the aforementioned fixed value. By this control, the number of data packets in the receiver buffer becomes maximum without the buffer overflowing and it is achieved that the output in the receiving device is interrupted as rarely as possible when problems occur in the receiving device or in the transmission medium and the transmission packet for a certain time does not arrive at the receiving device.
In the second exemplary embodiment, there is an in 4 shown data transmission device 407 that isochronous data to a transmission medium 408 sends out transit time delay identifier holding means 401 containing a runtime delay identifier 405 be liable; Maximum transmission data size holding means 402 , which is the maximum transmission data size 406 hold; Bandwidth allocation means 403 and transmitting / receiving means 404 ,
5 shows the required bandwidth to capture when sending isochronous data to P1394. The bandwidth of the isochronous data is the bandwidth corresponding to the time determined by the sum of the following times: a time T1 that elapses from the determination that the bus is not in use until requesting the occupancy; a transmission time T2, which is required until the arrival of the bus occupation request at the control node; a decision time T3 at the bus node control node; a transmission time T4 required for receiving the judgment result output from the occupancy control node; an occupation time T5 of the bus before the data transmission; a time T6 for outputting a signal indicating the transmission speed of the data; a time T7 needed to transmit the packet itself; a time T8 for outputting a signal indicating the transmission end; and a propagation delay time T9, which is needed until the arrival of the packet at the bus occupancy controlling node.
at this range is all values except T7 (the time those for transfer of the package itself will) of the transmission speed and the transmission data size become independent and determined by the number of relay nodes operating between the sending node and the bus occupancy controlling nodes. As it is at P1394 it is not necessary that the node controlling the bus occupation in is the middle of the connection, is the packet transfer time exceeding Time varies from node to node. Time for everyone To obtain nodes, the location of the node controlling the bus occupancy must be considered become.
If however, this time is obtained as a value based on the location of the Control node for the occupancy independent is, and this value for Any node connected to the bus is used should be the maximum Number of relay nodes present in the bus as maximum Number of relay nodes between the transmitter node and the bus occupancy controlling nodes are used.
Taking into account the fact that the transmitting node 603 who, as in 6 shown by the bus occupancy controlling node 601 around (N-1) relay node 602 with N connection times off, outputs a packet, and using the value specified in the standard P1394 will not do that for the Packet transfer time T oh used by GI. 1 expressed: T Oh = (1.777 + N × 0.494) μs (GI.1).
If this value is expressed by a unit used for bandwidth control at P1394, the bandwidth BW oh, which is not required for packet transmission (hereinafter referred to overhead bandwidth) through Eq. 2 expressed: BW Oh = 88.3 + N · 24.3 (GI.2).
The Unit of bandwidth used in P1394 is a value at which the bandwidth needed for transmission a 2-bit signal with a transmission speed of 100 MB / s is required, with 1 attaching.
The runtime delay identifier 405 becomes out of the connection topology with the transmission medium 408 and the overhead bandwidth can be determined as a single value by the value of this identifier. The runtime delay identifier 405 included in the propagation delay identifier holding means 401 is held in the initial state based on the number of maximum permissible connections for the transmission medium used.
If the transmission medium used is P1394, the value corresponding to an overhead bandwidth having 15 relay nodes with 16 connection times is set. The maximum transfer data size 406 which are in the maximum transmission data size holding means 402 is expressed expresses the maximum data size that may be included in a payload part that is a data part of an isochronous transfer packet used in P1394. The maximum transfer data size used here 406 expresses what the detected bandwidth 104 corresponds to that described in the first exemplary embodiment.
The packet format used in isochronous data transmission is the same format as that used in 3 the previous exemplary embodiment is shown. The size and number of data blocks included in the payload part are determined by the nature and speed of the data transferred.
In addition to the isochronous data, 20-byte data including the header is added to the packet. Of these, in the maximum transfer data size holding means, a sum of 8 bytes for the CIP header 206 and kept the data size of the isochronous data. Thus, the bandwidth required for detection prior to transmission is the sum of the bandwidth required when a packet having a size at which 12 Bytes are added to the maximum transmission data size, at which the speed used for the transmission will be transmitted, and the aforementioned overhead bandwidth.
7 shows the construction of a transmission PCR, a register for controlling the isochronous data transmission, which is located in the address space that each P1394 node has. The PCR is a 32-bit register and consists of a 1-bit online identifier 701 indicating whether the PCR is usable; a 1-bit communication link counter 702 indicating that the transmission controlled by the transmission PCR can be aborted during transmission; a 6-bit point-to-point connection counter 703 indicating the number of devices that controlled the PCR; an unused 2-bit field 704 ; a channel 705 indicating the channel number used to transmit isochronous 6-bit data; a 2-bit data speed 706 indicating the speed used for the transmission; a 4-bit overhead identifier 707 corresponding to the propagation delay identifier holding means; and a 10-bit payload size 708 corresponding to the maximum transmission data size holding means and the payload size by one unit of 4 Bit expresses.
In the first exemplary embodiment, the payload size may be 708 of the PCR as detected bandwidth 104 be used.
The transmission control device for controlling the transmission may control the transmission by writing values to the register, and may determine the transmission state at this time by reading the latches in the register. The transmitting device carries out the transmission if any value other than zero in the transmission connection counter 702 or the point-to-point connection counter 703 is written when the online identifier 701 of the transfer PCR 1 is. If, on the other hand, both values are zero, the output is aborted. Only if the point-to-point connection counter 703 0 and the transmission connection counter 702 1, the devices except the device that commanded the transmission start clear the transmission link counter 702 and can stop the transmission.
Because the runtime delay identifier 405 could have been converted to another identifier for a later reason, if the bandwidth detection means 403 capture the bandwidth, the bandwidth is determined by the propagation delay identifier 405 included in the propagation delay identifier holding means 401 and the maximum transmission data size 406 which are in the maximum transmission data size holding means 402 held, recorded. When bandwidth is detected, the bandwidth detection means reads 403 the maximum transmission data size 406 from the maximum transmission data size holding means 402 , add 12 bytes to the maximum transfer data size 406 and capture the bandwidth needed to transmit a packet of this size at the data rate included in the PCR 706 is necessary in order to obtain a packet size from the payload size for the aforementioned reason. The bandwidth detection means 403 read the runtime delay identifier 405 from the propagation delay identifier holding means 401 and add those from the propagation delay identifier 405 certain overhead bandwidth to the bandwidth for packet transmission.
The bandwidth detection means 403 give the bandwidth detected by the aforementioned result to the transmitting / receiving means 404 as a request for bandwidth allocation, and the transceiver means 404 give the received request for bandwidth allocation to the transmission medium 408 as an asynchronous packet to be sent to a bandwidth control node. As a result of the request, the received packet is sent to the bandwidth detection means 403 output. The bandwidth detection means 403 decide whether the bandwidth was detected from the result of the bandwidth allocation request. The transmission start can be done by writing to the transmission connection counter 702 PCR or in the point-to-point connection counter 703 be instructed based on the result of the bandwidth acquisition.
Under consideration The above method will become an example of bandwidth allocation below for the transmission explained by digital VCR data, which is currently being developed.
When the digital VCR data is transmitted using P1394, the data becomes all 480 Byte divided and transmitted as an isochronous packet. Thus, the value becomes 122 , in which 488 Byte as a unit of 4 Bytes are written as maximum transfer data size, while the value 488 Byte is the value obtained by adding the 8 bytes of the CIP header to the division unit of 480 Byte is received.
The bandwidth detection means 403 read the value 122 , which is the maximum transmission data size, from the maximum transmission data size holding means (payload size 708 ) and multiply it by 4 so the known payload size of 488 Byte is received. It should also be noted that the value 500 Byte by adding 12 bytes too 488 Byte is the size of a packet for the isochronization data. Based on the value of the data rate contained in the PCR 706 the bandwidth required for packet transmission is determined. With the bandwidth unit used at P1394, the bandwidth becomes 2000 when the data speed 706 indicates a transmission at 100 MB / s. When the data speed 706 However, if the transmission is 200 MB / s, the bandwidth becomes 1000, that is, half of 2000.
The bandwidth detection means 403 read a propagation delay identifier from the propagation delay identifier holding means included in the PCR (Overhead Identifier 707 ). The bandwidth detection means 403 have a correspondence table of overhead patterns depending on the bit pattern of the 4-bit propagation delay identifier given in Table 1, and the overhead bandwidth is found by reading the propagation delay identifier. Table 1 propagation delay Overhead bandwidth 0000 113 0001 137 0010 162 0011 166 0100 210 0101 235 0110 259 0111 283 1000 307 1001 332 1010 356
1011 380 1100 405 1101 429 1110 453 1111 477
The Sum of the resulting overhead bandwidth and the Value 2000, which is the packet bandwidth, is the detected bandwidth.
When the point-to-point connection counter 703 of the PCR is 0 and the transmission link counter 702 1, the transmission may be aborted by a node other than the node giving the start of transmission command, the transmission link counter 702 resets so that a different transmission is possible using the bandwidth used in the aborted transmission. In this case, the bandwidth used is determined from the propagation delay identifier contained in the PCR and the maximum transmission data size.
The block diagram of a transmitting device in such a circuit of transmission is in 8th shown. A first transmitting device 806 , which now performs the transmission, consists of propagation delay identifier holding means 801 containing a runtime delay identifier 804 hold; Maximum transmission data size holding means 802 , which is a maximum transmission data size 805 hold; and transceiver means 803 which is a packet between the transmitting / receiving means 803 itself and a transmission medium 807 send and receive. A second transmitting device 814 , which restarts the transmission, consists of transmitting / receiving means 808 which is a packet between the transmitting / receiving means 808 itself and the transmission medium 807 send and receive; Bandwidth acquiring means 809 ; Delay identifier holding means 810 containing a runtime delay identifier 812 hold; and maximum transmission data size holding means 811 , which is a maximum transmission data size 813 hold.
When the second transmitting device 814 the transmission of the first transmitting device 806 aborts and performs the transmission using the bandwidth provided by the first transmitting device 806 has been used, the transmission connection counter of the PCR of the first transmitting device is reset. In doing so, the bandwidth detection means read 809 the second transmitting device, the propagation delay identifier 804 included in the propagation delay identifier holding means 801 is held, which is part of the PCR of the first transmitting device 806 are, and the maximum transfer data size 805 which are in the maximum transmission data size holding means 802 is held.
In this case, since the node identifier of the first transmitting device 806 in the CIP header of the isochronous data package, which uses the in 3 has shown structure and is sent from the first transmitting device, the second transmitting device 814 the node identifier of the first transmitting device 806 which sends the data by receiving the data being sent and checking the CIP header.
Due to the propagation delay identifier 804 and the maximum transmission data size 805 that from the first transmitting device 806 read, search the bandwidth detection means 809 the second transmitting device 814 the bandwidth that the first transmitting device has detected and used in a similar manner as in the aforementioned conventional bandwidth detection. The bandwidth found here, the from the first transmitting device 806 has been detected by the second transmitting device 814 be used after the first sending device 806 the transmission has stopped.
It is not always necessary to have the data rate contained in the PCR 706 although the data speed that is used when reading from the first transmitting device 806 used bandwidth, usually by reading the data rate contained in the PCR 706 since it can be determined from the reception speed upon reception of an isochronous data packet to the node identifier of the first transmission device 806 to investigate.
The bandwidth detection means 809 compare the given bandwidth detected by the above method with the bandwidth similarly from the propagation delay identifier 812 which is in the second transmitting device 814 and in the maximum transmission data size holding means 811 held maximum transmission data size 813 is captured and is to be used. If the given bandwidth and the bandwidth to be used are different, additional bandwidth must be returned to the bandwidth control node, or an insufficient bandwidth must be recaptured.
If doing so, that of the first transmitting device 806 read runtime delay identifier 804 smaller than that in the propagation delay identifier holding means 810 the second transmitting device 814 held runtime delay identifier 812 may be the runtime delay identifier 812 the second transmitting device 814 the same value as that of the first transmitting device 806 read runtime delay identifier 804 accept. This is because the propagation delay identifier is determined only from the connection topology of the bus and the least propagation delay identifier can be used if it is a node connected to the same bus, although according to the calculation method used for the calculation of the later mentioned Runtime delay identifier is used, another value could be written at each node.
As stated above, the initial value of the propagation delay identifier holding means is a value corresponding to the case that the bus has the maximum composition permitted by the P1394 standard. Therefore, the second transmitting device has 814 which is assigned a bandwidth, an initial value as a propagation delay identifier 812 and on the other hand, the propagation delay identifier 804 the first transmitting device 806 effectively use the bandwidth having the transmission medium by choosing the smaller value after comparing the values, in which case the bandwidth is given, if a smaller value than the initial value is written by checking the connection topology of the bus.
9 shows the block diagram for the method when a transmission control device detects a propagation delay identifier. In the embodiment, there is a transmitting device 910 from transmitting / receiving means 907 for sending and receiving a packet to and from a transmission medium 906 and propagation delay identifier holding means 908 for holding a propagation delay identifier 909 , A transmission control device 905 consists of analytical tools 901 for analyzing the connection topology of the devices connected to the transmission medium, identifier determining means 902 for determining the propagation delay identifier according to the analysis result, identifier setting means 903 for setting the propagation delay identifier 909 in the propagation delay identifier holding means 908 the transmitting device 910 and transmitting / receiving means for transmitting and receiving a packet to and from the transmission medium 906 ,
The analytical means 901 Receive all self-identification packets issued by each node connected to the bus when resetting P1394, and analyze the tree structure of the bus using the information contained in the self-identification packets. By analyzing the tree structure, the number of relay nodes in the transmission between two nodes is determined, and the largest value is output. The identifier determination means 902 calculate the maximum propagation delay that could occur from the maximum number of relay nodes in the bus, by the analysis means 901 and use this value to determine the amount of overhead bandwidth that must be captured during isochronous data transfer. The identifier determination means 902 determine from the overhead bandwidth the most suitable propagation delay identifier and output it.
As correspondence between the number of relay nodes and the overhead bandwidth used here, for example, the values given in Table 2 can be used. Table 2 Number of relay nodes Overhead bandwidth 0 113 1 137 2 162 3 166 4 210 5 235 6 259 7 283 8th 307 9 332 10 356 11 380 12 405 13 429 14 453 15 477
The values given in Table 2 are maximum values that are independent of the location of the node controlling the bus occupation, and they were using GI. 2 calculated. It is also possible, the propagation delay considering to calculate the location of the node controlling the bus occupation in the bus. Even if in this case the maximum number the relay node present in the bus is the same, the Value less than the overhead bandwidth specified in Table 1 be. The values given in Table 1 are for the relationship between the overhead bandwidths and the bit patterns of the 4-bit propagation delay identifier used. The runtime delay identifier can be determined as above.
Thus, the identifier determining means obtain 902 the overhead bandwidth from the maximum number of the analysis resources 901 provided relay node and determine the propagation delay identifier from the overhead bandwidth and output it. The overhead bandwidth can be determined in only one value from the propagation delay identifier by determining such correspondence.
The identifier setters 903 receive the from the identifier-determining means 902 certain propagation delay identifier and write it in the propagation delay identifier holding means 908 the transmitting device 910 , Writing is done by writing to the PCR using an asynchronous packet.
As stated above, an identifier determined by the P1394 maximum connection topology is included in the propagation delay identifier holding means as an initial value 908 the transmitting device 910 written. To change this value, the connection topology of the bus must be analyzed and the maximum number of relay nodes must be determined. However, since isochronous data transmission is possible even if the propagation delay identifier is used as the initial value without analyzing the connection topology of the bus, not all transmitters need to be provided with the analysis means 901 for the connection topology, the identifier-determining means 902 or the identifier setters 903 be provided. In this case, since a larger bandwidth than the originally required bandwidth is detected, the bandwidth that the transmission medium has can not be effectively utilized.
The effective utilization of the bandwidth that the transmission medium has is achieved by connecting the transmission control device 905 with the transmission medium, by determining a propagation delay identifier by analyzing the connection topology of the devices connected to the bus and by setting the propagation delay identifier, which is considered suitable for the propagation delay identifier Haitemittel the transmitter connected to the bus. Since the propagation delay identifier holding means can be written over a bus when there is at least one interrogation control device in the bus, a smaller propagation delay identifier than the initial value can be set. Therefore, not all transmitters need analysis means 901 for the connection topology, identifier-determining means 902 etc, and the bandwidth that the Transmission medium can now be effectively utilized solely by using a propagation delay identifier expander table and overhead bandwidths (Table 1).
A another transmission control device as the transmitting devices, the propagation delay identifier holding means could have more corresponding runtime delay identifiers write as the value already set. As stated above, if the bandwidth detection means detects the bandwidth, a value in the propagation delay identifier holding means must be read, and based on the read value, the overhead bandwidth be determined.
For use in switching the transmitting devices, the propagation delay identifier held in the propagation delay identifier holding means must be the value that was used when the bandwidth was detected. Therefore, a transmission device for which a propagation delay identifier is set by the transmission control device is limited to the transmission device that does not transmit at that time. That is, a propagation delay identifier can be set only if both the transmission link counter 702 of the PCR as well as the point-to-point connection counter 703 are zero.
Of the most suitable value for a runtime delay identifier becomes original as a single value, if the connection topology of the Bus is determined. However, to get the most appropriate value The connection topology of the bus is analyzed, and all relay nodes between the nodes and in some cases the Location of the control node for The bus assignment in the bus must be error-free to be obtained. Therefor a complicated analysis is necessary. If only a few devices connected to the bus, the propagation delay identifier to a smaller value than that only on the number of devices based initial value that may be not the most appropriate value is to be set.
at P1394 is set by a standard that specifies the number of relay nodes between the farthest node 15 and the number of Connection times must be 16. If the number of buses connected node M is less than 17, the number of relay nodes between the farthest nodes never larger than (M-2), independent of which connection topology is chosen. Therefore, in this If the connection topology is not parsed and the runtime delay identifier can determined by (M-2), the maximum number of relay nodes from the number of nodes connected to the bus, as the number of nodes Relay node is set. If M is greater than 17, the value becomes 15 used, which is the maximum value the for P1394 permissible Values is. By setting a propagation delay identifier, the As stated above, the bandwidth can be complicated without Procedure can be used more effectively than in the case that the propagation delay identifier at all not set, even if the bandwidth that the transmission medium has, can not be fully utilized.
Consequently There may be several methods by which a transmitting device a runtime delay identifier determined, and there may be several transmission control devices for setting runtime delay identifiers in the same bus. Therefore, in the propagation delay identifier holding means, into the the runtime delay identifier is written for sometimes the most suitable, sometimes a longer propagation delay identifier written as this. in that case there could be a risk that the bandwidth that the transmission medium has, can not be used effectively. This problem can be avoided be by adding a runtime delay identifier only if it is smaller than the already set Value is where the value to be set is equal to the value already set value is compared.
There in the invention, the propagation delay identifier used in the bandwidth detection and the maximum transmission data size from the outside via the transmission medium can be read may be another device connected to the same transmission medium is to receive the detected bandwidth, which is why the procedure for Capture the bandwidth associated with a bandwidth conversion is if another transmitting device using the already transmitted bandwidth can be simplified.
In the invention, the bandwidth of a transmission medium can be effectively utilized by a transmission control device analyzing the connection topology of the device connected to the transmission medium and identifying a propagation delay due to the analysis result kator sets. Since the propagation delay identifier can be set outside the device via the transmission medium, it is possible to effectively use the bandwidth having the transmission medium by having at least one transmission control device in the transmission medium, even though not all the transmission means analyze the connection topology analyzing means have device connected to the transmission medium.
In According to the invention, the bandwidth can be effectively used without that a complicated procedure is required by an appraisal based on the number of with the transmission medium connected devices when the connection topology the one with the transmission medium connected devices is analyzed.
Arrival time tracker
Zeitstempelzufüger
Transmission time control unit
Recorded bandwidth
Bandwidth Informationszufügungsmittel
108 112, 122
necessary Bandwidth in the transmission medium
dates with added Bandwidth information
command signal for recording and playback
203a, 203b, 206
SID (Source Node ID; Source Node ID)
FDF (Format Dependent Field; format-dependent field)
401 801, 810, 908
Propagation delay identifier holding means
402 802, 811
Maximum transmission data size holding means
404 803, 808, 904, 907
405 804, 812, 909
406 805, 813
407 806, 814, 910
408 807, 906
Busbelegungsanforderung
Busbenutzungsgenehmigung
control node for bus usage
Control device ( 905 ) for controlling a plurality of transmitting devices ( 910 ), wherein the plurality of transmitting devices have a connection topology as a result of interconnecting by a transmission medium ( 906 ), each of the transmitting devices having propagation delay identifier holding means ( 908 ) for having a propagation delay identifier ( 909 ) based on the connection topology of the transmission medium ( 906 ) based propagation delay, comprising: anatizing means ( 901 ) for analyzing the connection topology; Identifier-determining means ( 902 ) for determining the propagation delay identifier ( 909 ) according to one of the analysis means ( 901 ), characterized by : identifier reading means for reading a currently stored propagation delay identifier ( 909 ) from the propagation delay identifier holding means ( 908 ) of a transmitting device and identifier setting means ( 903 ) for determining whether a value of the propagation delay identifier determined by the identifier determination means is smaller than a value of the currently stored propagation delay identifier read by the identifier reading means, and if the value is smaller, for setting in the identifier determining means ( 902 ) certain propagation delay identifier ( 909 ) in the propagation delay identifier holding means ( 908 ); wherein a bandwidth of the transmission medium available for a transmitting device depends on the connection topology.
Control device ( 905 ) according to claim 1, characterized in that the analysis means ( 901 ) determine the connection topology corresponding to a number of maximum response devices based on a number of the transmission medium ( 906 ) is assumed.
System with: a transmission medium ( 906 ); a plurality of transmitting devices ( 910 ) with a connection topology as a result of interconnecting by the transmission medium ( 906 ), each of the transmitting devices having propagation delay identifier holding means ( 908 ) for holding a propagation delay identifier ( 909 ) based on the connection topology of the transmission medium ( 906 ) based propagation delay, wherein a bandwidth of the transmission medium available for a corresponding transmission device depends on the connection topology; and the control device ( 905 ) according to claim 1 or 2.
DE69635934T 1995-04-28 1996-04-25 Data transmission device, data receiving devices and data transmission control device Expired - Lifetime DE69635934T2 (en)
JP10555495 1995-04-28
JP14720995 1995-06-14
JP19634595 1995-08-01
DE69635934T2 true DE69635934T2 (en) 2006-10-05
DE69631182T Expired - Lifetime DE69631182T2 (en) 1995-04-28 1996-04-05 Data transmission method
DE69631182A Expired - Lifetime DE69631182D1 (en) 1995-04-28 1996-04-05 Data transmission method
DE69630409A Expired - Lifetime DE69630409D1 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69636353A Expired - Lifetime DE69636353D1 (en) 1995-04-28 1996-04-25 Datenübetragungsvorrichtung.
DE69635934T Expired - Lifetime DE69635934T2 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving devices and data transmission control device
DE69630409T Expired - Lifetime DE69630409T2 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69636353T Expired - Lifetime DE69636353T2 (en) 1995-04-28 1996-04-25 Data transfer device
DE69615044T Expired - Lifetime DE69615044T2 (en) 1995-04-28 1996-04-25 Data transmitter, data receiver and data transmission control
DE69637212A Expired - Lifetime DE69637212D1 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69635934A Expired - Lifetime DE69635934D1 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving devices and data transmission control device
DE69634932T Expired - Lifetime DE69634932T2 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69615044A Expired - Lifetime DE69615044D1 (en) 1995-04-28 1996-04-25 Data transmitter, data receiver and data transmission control
DE69634932A Expired - Lifetime DE69634932D1 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69637212T Expired - Lifetime DE69637212T2 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
DE69637887A Expired - Lifetime DE69637887D1 (en) 1995-04-28 1996-04-25 Data transmission device, data receiving device and control device for data transmission
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