JP2005176232A - Communication system employing isochronous transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system capable of differentiating a time required for dubbing from an ordinary video reproducing time and to provide a communication apparatus employed for the system. <P>SOLUTION: The communication apparatus includes: a means for reading a packet sequence of moving picture and/or audio data recorded on a recording medium at an arbitrary bit rate; a means for attaching a time stamp as a first header to each packet of the packet sequence read at the bit rate to make each packet a source packet; a means for dividing the source packet into a plurality of data blocks; and a means for carrying out isochronous transfer by making the arbitrary number of the data blocks and a second header one isochronous packet data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system, and more particularly, to a communication system that transmits and receives MPEG video data and the like using isochronous transfer such as IEEE 1394 standard. The present invention is suitable, for example, for a dubbing system that replicates audiovisual (AV) data.

A dubbing system 400, which is an example of a conventional dubbing system, will be described with reference to FIGS. The dubbing system 400 is a dubbing system using isochronous transfer defined by the IEEE 1394 standard (Non-patent Documents 1 and 2). Hereinafter, a communication interface conforming to the IEEE 1394 standard is referred to as an IEEE 1394 interface.

  FIG. 6 is a schematic block diagram of the dubbing system 400. The moving image data on the disc 401 on the transmission side is read by the recording / playback processing unit 402 and then sent to the data processing unit 403. The data processing unit 403 performs a decoding process for displaying a moving image on the display unit 404. The data read by the recording / playback processing unit 402 is input to the IEEE 1394 interface 405, subjected to predetermined packetization described later, and input to the receiving-side IEEE 1394 interface 407 via the IEEE 1394 serial bus 406. The receiving side decodes the transmitted data by the data processing unit 408 and displays it on the display unit 409 and records it on the disk 411 via the recording / playback processing unit 410.

FIG. 7 shows a flow of packetizing MPEG transport stream data, which is recorded moving image data, for the IEEE 1394 serial bus 406. The recorded data string 501 is read by the recording / playback processing unit 402 and input to the 1394 interface unit 405 for each 188-byte MPEG-TS packet 502. At this time, time stamp data is added to each MPEG-TS packet 502 as a header to become a source packet 503. The source packet is then divided into 8 data blocks 504. Depending on the bit rate of the MPEG-TS data, several (here, four as an example) blocks 505 are made into one isochronous data 506. A common isochronous packet (CIP) header 507, an isochronous packet header 508, and CRC data 509 are added to each isochronous data to form an isochronous packet 510. In this example, a packet consisting of four data blocks is transmitted in each isochronous cycle, and the bit rate of MPEG-TS data is about 6.016 Mbps. A method of transmitting MPEG-TS data as an isochronous packet defined by the IEEE 1394 standard is disclosed in Non-Patent Document 3, for example. As a prior art, there is, for example, Patent Document 1.
JP 2001-119660 A IEEE Std 1394-1995, IEEE Standard for a High Performance Serial Bus IEEE Std 1394a-2000, IEEE Standard for a High Performance Serial Bus-Amment 1 IEC 61883-4, Consumer and audio / video equipment-Digital interface-Part 4, MPEG2-TS data transmission

  However, in the conventional dubbing system, when AV data is isochronously transferred, the time required for dubbing is as long as the video playback time. In other words, if it is AV data for one hour, it takes one hour for dubbing.

Further, when dubbing is being performed, the transmission side cannot perform operations for viewing data such as retroactively browsing data, performing searches, and fast-forwarding. This problem,
This is a problem that cannot be solved even by the dubbing system described in Patent Document 1.

  Accordingly, an object of the present invention is to provide a communication system and a communication device used for the communication system that can make the time required for dubbing different from the normal video playback time.

  The communication apparatus according to one aspect of the present invention includes means for reading a packet sequence of moving image and / or audio data recorded on a recording medium at an arbitrary bit rate, and the packet sequence read at the bit rate. Means for adding a time stamp as a first header to each packet to make each packet a source packet, means for dividing the source packet into a plurality of data blocks, an arbitrary number of the data blocks, and a second Means for isochronous transfer as a single isochronous packet data.

  The packet sequence is, for example, a packet sequence of an MPEG transport stream. The bit rate and the size of the isochronous packet data may be changed according to the reproduction state of the recording medium. In fast-forward playback in which the playback state plays back the data at a speed greater than the normal playback speed, the bit rate and the isochronous packet data are larger than the bit rate and isochronous packet data at the normal playback speed, and the playback state is In slow playback in which the data is played back at a speed lower than the normal playback speed, the bit rate and the isochronous packet data are smaller than the bit rate and isochronous packet data at the normal playback speed, and the playback state is paused. The packet sequence is not read and the isochronous packet data is not transmitted. When the playback state is reverse playback, the packet sequence is read, but the isochronous packet data is not transmitted. Also good. You may further have a means to display the said data according to the said reproduction | regeneration state.

  The reading means is used for the display means, and is used for the isochronous transfer, the first task for reading the data at a first speed according to the reproduction state of the recording medium, and the recording medium. And a second task for reading the data at a second speed that is faster than the first speed regardless of the playback state of the first task, and the first task and the second task operate alternately Also good.

  According to another aspect of the present invention, there is provided a communication method of reading a packet sequence of moving image and / or audio data recorded on a recording medium at a bit rate N times the normal reproduction speed of the data; Generating an isochronous packet having a data amount N times the data amount on isochronous transfer when the data is dubbed at the normal reproduction speed from the packet sequence read at the bit rate. Features. You may further have the step which displays through the buffer for changing the said N times bit rate into the bit rate corresponding to the said normal reproduction speed. If N is larger than 1, the step of thinning out the data read at the N times bit rate and writing it to the buffer; if N is smaller than 1, the frame until a frame image is output from the buffer. And a step of displaying a frame image immediately before the image. The recording medium may further include a reproduction process, and the reproduction state by the reproduction step and the reading step may be irrelevant.

  A communication system according to still another aspect of the present invention is a communication system including a first communication device and a first communication device that is communicably connected to the first communication device through an IEEE 1394 serial bus. The first communication device includes a unit for reading a packet sequence of moving image and / or audio data recorded on the first recording medium at an arbitrary bit rate, and the read at the bit rate. Means for adding a time stamp as a first header to each packet in the packet sequence to make each packet a source packet, means for dividing the source packet into a plurality of data blocks, and any number of the data blocks; Means for isochronously transferring the second header as one isochronous packet data, and the second communication device is configured to transmit the IE Characterized in that it has a means for recording the data of the moving image and / or audio based on the analyst Seo black eggplant packet data received on the second recording medium through the E1394 serial bus.

  A communication method according to another aspect of the present invention uses a communication system that includes a first communication device and a first communication device that is communicably connected to the first communication device through an IEEE 1394 serial bus. In the communication method, the first communication device transmits a packet sequence of moving image and / or audio data recorded on a first recording medium at a bit rate N times the normal reproduction speed of the data. A step of reading, wherein the first communication device has a data amount N times the amount of data on isochronous transfer when the data is dubbed from the packet sequence read at the bit rate at the normal reproduction speed. Generating the isochronous packet, and the second communication device transmits the moving image and the video at a speed corresponding to the data amount of the isochronous packet. / Or to have a step of recording the audio data on the second recording medium and said. The first and / or second communication device may further include a step of displaying the N times bit rate via a buffer for changing the bit rate to a bit rate corresponding to the normal reproduction speed.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to this invention, the communication system which can make time required for dubbing different from the normal reproduction time of an image | video, and a communication apparatus used for it can be provided.

  Hereinafter, a dubbing system 100 as an embodiment of the present invention will be described. Here, FIG. 1 is a schematic block diagram of the dubbing system 100. As shown in FIG. 1, the dubbing system 100 includes a reproduction communication device 110, a recording communication device 120, and an IEEE 1394 serial bus 130, and reproduces and displays AV data recorded on the recording medium as MPEG-TS. A dubbing system that duplicates this onto another recording medium. The dubbing system 100 is characterized in that dubbing is performed at a speed corresponding to the playback state of the playback communication device 110, and the time required for dubbing is determined according to the playback state of the playback communication device 110.

  The playback communication device 110 includes a recording medium 111 storing moving image data and / or audio data (AV data) as a dubbing source, a recording / playback processing unit 112, a memory 113, a data processing unit 114, and a display unit 115. And an IEEE 1394 interface 116. On the other hand, the recording communication apparatus 120 includes a recording medium 121 as a dubbing destination, a recording / playback processing unit 122, a memory 123, a data processing unit 124, a display unit 125, and an IEEE 1394 interface 126. The types of the recording media 111 and 121 may be any type such as an optical disk and a semiconductor memory.

  In operation, the AV data of the recording medium 111 is read by the recording / playback processing unit 112 and temporarily stored in the memory 113. The memory 113 is used as a buffer for changing data read at a bit rate corresponding to a reproduction state to a normal bit rate.

  For example, when fast-forward playback at twice the normal playback speed is performed, data is read from the recording medium 111 by the recording / playback processing unit 112 at a double bit rate, thinned out, and sent to the memory 113. . FIG. 2 shows an example of data thinning. The read data string 201 is input to the memory 113 and a write enable signal 202 is given to the memory 113 at the same time. In this example, a write enable signal is given every 1 GOP (Group of Pictures) every 15 frames, and data thinned out every 1 GOP is written into the memory 113. Next, this data is sent to the data processing unit 114 at the same read bit rate as in normal reproduction. The data processing unit 114 decodes the data and sends it to the display unit 115, which displays it. As a result, the display unit 115 displays a discontinuous moving image about every 15 frames as a monitor image at the time of dubbing. On the other hand, the data read by the recording / playback processing unit 112 is input to the IEEE 1394 interface 116.

  On the other hand, in the case of performing slow playback at a speed that is 1/2 times the normal playback, data is read from the recording medium 111 by the recording / playback processing unit 112 at a bit rate that is 1/2 times and sent to the memory 113. . Data is sequentially read from the memory 113 and sent to the data processing unit 114. The data processing unit 114 decodes the data and sends it to the display unit 115, which displays it. The display unit 115 displays the previous frame image until the next frame image arrives.

  In the case of performing reverse reproduction, data read in reverse from the recording medium 111 in units of 1 GOP is sent to the data processing unit 114 via the memory 113, and the order of frames in the GOP is reversed to display the display unit 115. Is displayed.

  In the case of performing the pause state, the recording / playback processing unit 112 does not read data from the recording medium 111, and therefore, no data is transferred to the memory 113, the data processing unit 114, and the display unit 115, and the display unit 115 is temporarily Displays the frame image when the stop state is reached. The display unit 115 has a frame buffer for holding the above-described frame image.

  As described above, the reproduction bit rate is changed according to the reproduction state, and the reproduction state is obtained by performing processing in synchronization with each processing unit of the memory 113, the recording / reproduction processing unit 112, the data processing unit 114, and the display unit 115. The same video can be displayed.

  Hereinafter, an example of packetization according to the read bit rate will be described with reference to FIG. When fast-forward playback is performed, the recorded data string 301 is read by the recording / playback processing unit 112 at a bit rate twice that of normal playback, and is input to the IEEE1394 interface 116 for each 188-byte MPEG-TS packet 302. The At this time, time stamp data is added as a header to each MPEG-TS packet 302 to become a source packet 303. Next, this source packet is divided into eight data blocks 304 as in the conventional example. Eight blocks 305 are defined as one isochronous data 306. The isochronous data 306 has a data amount twice that of the conventional isochronous data 506. A common isochronous packet (CIP) header 307, isochronous packet header 308, and CRC (Cyclic Redundancy Check) data 309 are added to each isochronous data 306 to form an isochronous packet 310. In this example, a packet 310 consisting of eight data blocks 305 is transmitted in each isochronous cycle, and the bit rate of MPEG-TS data is about 12.032 Mbps.

  An example of packetization when performing slow reproduction will be described with reference to FIG. As described above, the recorded data string 301 is read out by the recording / playback processing unit 112 at a bit rate that is ½ times that during normal playback, and is input to the IEEE1394 interface 116 for each 188-byte MPEG-TS packet 302. Is done. Similarly, at this time, time stamp data is added to each MPEG-TS packet 302 as a header to form a source packet 303, which is divided into eight data blocks 304. Two blocks 305 become one isochronous data 320. The isochronous data (payload data) 320 has a data amount that is ½ times that of the conventional isochronous data 506. A common isochronous packet (CIP) header 321, isochronous packet header 322, and CRC data 325 are added to each isochronous data to form an isochronous packet 330. In this example, a packet 330 composed of two data blocks 305 is transmitted in each isochronous cycle, and the bit rate of MPEG-TS data is about 3.008 Mbps.

  When reverse playback is performed, the MPEG-TS packet read from the recording medium 111 is sent to the memory 113 but is not sent to the IEEE 1394 interface 116. At this time, the IEEE1394 interface 116 transmits only the CIP header added to the isochronous packet.

  When the suspension is performed, data is not read from the recording medium 111, and therefore data transmission via the IEEE 1394 interface 116 is not performed. The display unit 115 displays the last decoded frame data.

  Returning to FIG. 1 again, the operation of the recording communication apparatus 120 will be described. The packet generated by the playback communication device 110 is input to the IEEE 1394 interface 126 of the recording communication device 120 via the 1394 bus 130. The recording communication device 120 inputs such data to the memory 123. The memory 123 is used as a buffer for sending data input from the IEEE 1394 interface 126 to the data processing unit 124 at a normal bit rate.

  When the playback communication device 110 performs normal playback, the received MPEG-TS packet is sent to the memory 123 as it is, decoded by the data processing unit 124 and displayed on the display unit 125.

  When the playback communication device 110 performs fast-forward playback, the data thinned out by sending an enable signal to the memory 123 for each GOP as in the playback communication device 110 is sent to the memory 123 and the data processing unit 124. Is displayed on the display unit 125. At this time, the enable and disable signals for the memory may count the number of packets received by the IEEE 1394 interface 126 and output them every 1 GOP, or count the number of MPEG-TS packets received by the recording / playback processing unit 124. By doing so, you may make it output for every 1 GOP.

  When the playback communication device 110 performs slow playback, similarly to the playback communication device 110, the received data is written into the memory 123, sequentially decoded by the data processing unit 124, and displayed on the display unit 125.

  When the playback communication device 110 performs reverse playback and pause, processing is performed by the same means as the playback communication device 110.

  On the other hand, data input from the IEEE 1394 interface 126 is input to the recording / playback processing unit 122, and image data is written to the recording medium 121 at a speed corresponding to the received isochronous payload size. At this time, if the isochronous packet is only a null packet including only the CIP header, writing to the recording medium 121 is not performed.

  When dubbing is performed with such a configuration, regardless of whether the playback communication device 110 is in the playback state, such as fast forward, reverse playback, slow playback, or pause, data on the recording medium 111 is not lost. Dubbing can be performed using isochronous transfer. In this embodiment, an example in which fast-forward playback is doubled and slow playback is halved has been described. However, by changing the number of data blocks encapsulated in one isochronous data, the playback speed can be increased several times. Even if there is, it is possible to respond. Also, the monitor display method during dubbing is only an example.

  In the above example, the transmission rate changes according to the playback state of the playback communication device 110 during dubbing, and the recording communication device 120 can only record according to that rate. That is, when the recording communication device 120 is in reverse playback and pause, data is not transmitted, and dubbing is not completed unless reverse playback and pause are released. In addition, in the case of slow reproduction of 1/2 times, it takes 2 times dubbing time. Therefore, in the dubbing system 100 shown in FIG. 1, a method for allowing the playback communication device 110 to freely perform playback operations such as fast forward and rewind and to perform high speed dubbing will be described with reference to FIG. 6. To do. In the case of fast-forwarding, the dubbing time is half of the normal time, so the above method can be adopted.

  First, reading of data during normal reproduction is performed by two tasks 350 and 360. During normal playback, in addition to the read-only task 350 that is always started in the playback communication device 100, a task 360 for reading data and writing it into the memory 113 is started. Here, each task operates alternately.

  The task 350 reads data from the recording medium 111 at twice the speed of normal playback in the RUN state 352, and performs isochronous packet transfer with a payload size twice that of normal transfer as in the above-described embodiment. Do. When the task 350 is in the RUN state 352, an enable signal is sent to the memory 113, and the read data is not transmitted to the memory 113. On the other hand, when the task 360 is in the RUN state 362, the task 360 reads data at a normal reading speed, sends the data to the memory 113, is decoded by the data processing unit 114, and is displayed on the display unit 115. At this time, an enable signal is sent to the IEEE 1394 interface 116, and no data is transmitted. In reverse playback, data is read from the recording medium 111 at twice the speed of normal playback by the task 350 in the same manner as described above, and the isochronous of the payload size that is twice that in normal transfer as in the above embodiment. Packet transfer is performed. The task 360 reads data at the reverse playback speed, sends the data to the memory 113, is decoded by the data processing unit 114, and is displayed on the display unit 115. Similarly, regarding the slow playback and pause, the task 350 reads data from the recording medium 111 at twice the normal playback speed in the RUN state 352, and the data at the normal double rate through the IEEE 1394 interface 116. When transmission is performed and the task 360 is in the RUN state 362, data is read from the recording medium 111 at a speed corresponding to the reproduction state and displayed on the display unit 115.

  In this way, dubbing can be realized at a high speed twice as fast regardless of the playback state of the playback communication device 110. Further, at the time of dubbing, the recording communication apparatus 120 may or may not perform display by thinning the display unit 125 as in the above-described embodiment. In this embodiment, the example in which the reading speed of the task 350 is twice as fast as normal is described. However, the reading speed can be increased by changing the number of data blocks encapsulated in one isochronous data. It is possible to do.

  As described above, according to the dubbing system 100 of the present embodiment, the time required for dubbing can be made different from the normal video playback time. That is, in one embodiment, dubbing can be performed at a speed corresponding to the playback state of the playback communication device 110, and in another embodiment, dubbing can be performed faster than the playback state of the playback communication device 110. Become.

1 is a schematic block diagram of a dubbing system according to a first embodiment of the present invention. 3 is a timing chart for explaining a write timing to a transmission side memory of the system shown in FIG. 1. It is a figure for demonstrating an example of the packet generation flow by the transmission side of the system shown in FIG. It is a figure for demonstrating another example of the packet generation flow by the transmission side of the system shown in FIG. It is a figure for demonstrating another example of the packet generation flow by the transmission side of the system shown in FIG. It is a schematic block diagram of the conventional dubbing system. It is a figure for demonstrating the packet generation flow of the transmission side of the system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image pick-up apparatus 110 Operation means 120 Operation amount detection circuit 122, 123 Zoom speed calculation means 124 Frequency calculation circuit 126 Reset switch 127, 127A Reset circuit 128 Memory 129 Attachment detection means 130 Drive circuit 132 Actuator 134 Lens individual information storage memory 140 Lens 144 Conversion lens 150 CCD
152 Signal Processing Circuit 154 Recording Unit 160 Recording Operation Switch

Claims (13)

Means for reading out a packet sequence of moving image and / or audio data recorded on a recording medium at an arbitrary bit rate;
Means for adding a time stamp as a first header to each packet of the packet sequence read at the bit rate to make each packet a source packet;
Means for dividing the source packet into a plurality of data blocks;
A communication apparatus comprising: an arbitrary number of the data blocks and means for isochronously transferring the second header as one isochronous packet data.   The communication apparatus according to claim 1, wherein the packet sequence is a packet sequence of an MPEG transport stream.   The communication apparatus according to claim 1, wherein the bit rate and the size of the isochronous packet data are changed according to a reproduction state of the recording medium. In fast forward playback in which the playback state plays back the data at a speed greater than the normal playback speed, the bit rate and the isochronous packet data are larger than the bit rate and isochronous packet data of the normal playback speed,
In the slow playback in which the playback state plays back the data at a speed lower than the normal playback speed, the bit rate and the isochronous packet data are smaller than the normal playback speed bit rate and the isochronous packet data,
When the playback state is paused, the packet sequence is not read and the isochronous packet data is not transmitted,
4. The communication apparatus according to claim 3, wherein when the reproduction state is reverse reproduction, the packet sequence is read, but the isochronous packet data is not transmitted.   4. The communication apparatus according to claim 3, further comprising means for displaying the data according to the reproduction state. The reading means includes
A first task that is used for the display means and reads the data at a first speed according to a reproduction state of the recording medium;
A second task that is used for the isochronous transfer and reads the data at a second speed faster than the first speed regardless of a reproduction state of the recording medium;
The communication device according to claim 5, wherein the first task and the second task operate alternately. Reading a packet sequence of moving image and / or audio data recorded on the recording medium at a bit rate N times the normal reproduction speed of the data;
Generating an isochronous packet having a data amount N times the amount of data on isochronous transfer when the data is dubbed at the normal reproduction speed from the packet sequence read at the bit rate. A communication method characterized by the above.   8. The method according to claim 7, further comprising the step of displaying through a buffer for changing the N times bit rate to a bit rate corresponding to the normal playback speed. If N is greater than 1, thinning out the data read at the N times bit rate and writing to the buffer;
8. The method of claim 7, further comprising the step of displaying the previous frame image of the frame image until a frame image is output from the buffer if N is less than one. The method further includes the step of reproducing the recording medium,
The method according to claim 7, wherein the reproduction state by the reproduction step and the reading step are irrelevant. A communication system comprising: a first communication device; and a first communication device that is communicably connected to the first communication device through an IEEE 1394 serial bus,
The first communication device is:
Means for reading a packet sequence of moving image and / or audio data recorded in the first recording medium at an arbitrary bit rate;
Means for adding a time stamp as a first header to each packet of the packet sequence read at the bit rate to make each packet a source packet;
Means for dividing the source packet into a plurality of data blocks;
Means for isochronously transferring an arbitrary number of the data blocks and the second header as one isochronous packet data;
The second communication device includes means for recording the moving image and / or audio data on a second recording medium based on the anomaly packet data received via the IEEE 1394 serial bus. A communication system. A communication method using a communication system having a first communication device and a first communication device that is communicably connected to the first communication device through an IEEE 1394 serial bus,
The first communication device reads a moving image and / or audio data packet sequence recorded on a first recording medium at a bit rate N times the normal reproduction speed of the data;
The first communication device has an isochronous packet having a data amount N times the amount of data on isochronous transfer when dubbing the data at the normal reproduction speed from the packet sequence read at the bit rate. A step of generating
The second communication apparatus includes a step of recording the moving image and / or audio data on a second recording medium at a speed corresponding to the data amount of the isochronous packet.   The first and / or second communication device further includes a step of displaying the N times bit rate through a buffer for changing to a bit rate corresponding to the normal reproduction speed. The method of claim 12.