JP2007034931A - Communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high-speed dubbing of MPEG moving image data or the like and to improve user's operability by using isochronous transmission of an IEEE1394 or the like. <P>SOLUTION: When performing high-speed dubbing of MPEG-TS moving image data or the like using the isochronous transmission of an IEE1394 or the like, an external device connected by, for example, asynchronous communication is notified so as to read video data from a recording medium at double speed of a normal speed to decode the video data at the double speed. In the asynchronous communication, negotiations are performed by a cts command. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication apparatus that transmits and receives MPEG moving image data and the like using isochronous transmission such as IEEE1394.

  Conventionally, there is an apparatus for performing dubbing using IEEE1394 (hereinafter referred to as 1394) isochronous transmission while reproducing moving image data recorded on a recording medium. FIG. 4 shows an outline of the apparatus when the recording medium is a disk.

  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). Further, the data read by the recording / playback processing unit (402) is input to the 1394 interface unit (405). Then, predetermined packetization is performed as described later, and the packet is input to the 1394 interface unit (407) on the receiving side via the 1394 cable (406). On the receiving side, the transmitted data is decoded by the data processing unit (408) and displayed on the display unit (409). The data is recorded on the disk (411) by the recording / playback processing unit (410).

  FIG. 5 shows a flow of packetizing MPEG transport stream data (hereinafter referred to as MPEG-TS), which is recorded moving image data, into 1394 isochronous packets. The recorded data string (501) is read by the recording / playback processing unit, and is input to the 1394 interface means for each 188-byte MPEG-TS packet (502). At this time, time stamp data is added as a header to each MPEG-TS packet (502) to form 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 used as one isochronous data (506). Each isochronous data is added with a common isochronous packet (CIP) header (507), isochronous packet header (508), and CRC data (509) to form an isochronous packet (510).

  In this example, a packet composed of four data blocks is transmitted in each isochronous cycle, and the bit rate of MPEG-TS data is about 6.016 Mbps.

  The isochronous communication is described in “IEEE Std 1394-1995 / IEEE Standard for a High Performance Serial Bus”. A method for transmitting MPEG-TS data as 1394 isochronous packets is described in IEC 61883-4: Consumer audio / video Equipment Digital interface Part 4: MPEG2-TS data transmission.

As another conventional example, Patent Document 1 can be cited.
Japanese Patent Laid-Open No. 2002-245111

  Conventionally, however, when an image signal is transmitted using isochronous transmission, the time required for dubbing is the same as the video playback time. In other words, if it was a 1 hour video source, it took 1 hour to dub.

  In view of the above problems, an object of the present invention is to enable high-speed dubbing.

  It is another object of the present invention to improve user operability by enabling negotiation by a command during dubbing.

  In order to solve the above problems, the communication apparatus of the present invention includes a reading means for reading a data string recorded on a recording medium at a bit rate of an arbitrary multiple during normal reproduction, and the read data string Packetizing means for adding a time stamp as a first header to the packet, blocking means for dividing the packet into a plurality of data blocks, the data block and the first header, Comprises a transmission means for synchronously transferring different second headers as synchronous packet data, wherein the transmission means transmits a data string including read bit rate information of the read means It is characterized by.

  As described above, according to the present invention, data dubbing can be performed at high speed using isochronous transmission.

In addition, it is possible to negotiate by command, so user operability
































Has the effect of improving.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  The configuration of a disk recorder that is an embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a circuit block diagram of a disk recorder using a disk such as a DVD.

  First, the flow of signals during recording and each block will be described.

  11 is MPEG codec, 12 is internal bus, 13 is DRAM, 14 is system control CPU (hereinafter referred to as CPU), 15 is error correction circuit (hereinafter referred to as ECC), 16 is buffer, 17 is modulation circuit, and 18 is playback Recording amplifier, 19 is a laser pickup, 20 is a recording medium such as an optical disk, 21 is a motor drive circuit, 22 is a spindle motor, 23 is a clock generation circuit, 24 is a liquid crystal drive circuit, 25 is a liquid crystal panel, and 26 is a digital interface ( (Hereinafter referred to as DIF).

  A digital video signal is input from an input terminal (not shown) or a camera unit (not shown).

  The digital video signal is sent to the MPEG codec 11 via the internal data bus 12 as 16-bit parallel data, for example.

  The MPEG codec 11 compresses the moving image data to about 1/60 according to the MPEG-2 format, for example, using the DRAM 13 as a video memory.

  The compressed video data is output to the system internal bus in accordance with CPU instructions.

  On the other hand, although the audio signal is not shown, for example, the audio signal obtained from the microphone built in the camera (not shown) is AD converted, compressed as software processing by the CPU 14, and output by the MPEG codec 11 Multiplexed with data, an MPEG-TS packet is generated.

  Also, the packet data that has been blocked is input to the DIF 26 from the outside via an interface cable (not shown).

  As described in the above-described conventional example, the packet data that has been blocked is divided into several data blocks from a source packet in which time stamp data is added as a header to an MPEG-TS packet that is an original signal. After that, several such data blocks are merged into one isochronous data according to the bit rate of MPEG-TS data, and each isochronous data includes a common isochronous packet (CIP) header, an isochronous packet header, and CRC data. It is added as an isochronous packet. The data block is temporarily stored in the DRAM 13 and then output to the internal bus 12 as an MPEG-TS packet from which the headers are deleted.

  The above-mentioned MPEG-TS packet is sent to the modulation / demodulation circuit 17 via the buffer 16 for avoiding a write error due to vibration or impact received by the optical disk 20 as a recording medium after the error correction code is added by the ECC circuit 15. It is done.

  Reference numeral 21 denotes a motor drive circuit in which tracking, focus, disk spindle servo circuit and the like are integrated.

  The MPEG-TS packet is modulated by the modulation / demodulation circuit 17 and recorded on the optical disc 20 by the laser pickup 19. At this time, the motor drive circuit 21 appropriately controls the rotation speed of the spindle motor 22 and the tracking and focus of the pickup 19.

  Next, a case where video data is reproduced from the recording medium 20 such as an optical disk will be described.

  Basically, a signal flows in the reverse of the recording state.

  First, the data string recorded by the laser pickup 19 is read from the recording medium 20 in a modulated state, and the waveform equalization and servo signal are detected by the modulation / demodulation circuit 17, and the MPEG-TS packet is passed through the buffer 16 to the inside of the system. Output to bus 12.

  At this time, even if a data reading error occurs during reading due to the impact received by the media and the pickup as in the case of recording, the buffer 16 accumulates data for several seconds, thereby eliminating the influence of the impact and the like. Continuous playback is possible.

  Data transfer of the video and audio data on the system internal bus 12 is controlled by an instruction from the CPU 14, and the original video data is restored by the MPEG codec 11 by the decompression operation.

  For example, the signal is converted into an appropriate video signal such as an NTSC signal or a PAL signal, and then an attribute signal of video data such as a recording time and a transfer rate is superimposed as character information by a character generator (not shown), Displayed as a playback image on panel 25.

  The video signal can be displayed on a display device such as an external TV via a video output terminal (not shown), for example.

  The liquid crystal drive circuit 24 drives the liquid crystal panel 25 based on the clock signal input from the clock generator 23 when the liquid crystal panel is displayed.

  In the DIF 26, blocked packet data is output to the outside through an interface cable (not shown).

  The MPEG-TS packet is temporarily stored in the DRAM 13, and the time stamp data is added as a header to become a source packet.

  The source packet is divided into several data blocks and read from the DRAM.

  The number of packets read from the DRAM 13 at a time is determined according to the bit rate of MPEG-TS data.

  These packets are merged into one isochronous data by DIF 26, and a CIP header, isochronous packet header, and CRC data are added to each isochronous data to form an isochronous packet.

  The isochronous packet is output to the outside via an interface cable (not shown).

  In the present invention, when video data is reproduced from the recording medium 20 such as the optical disk, the data can be read at an arbitrary bit rate.

  For example, a case where reproduction is performed at a bit rate twice as normal will be described.

  When the double speed reproduction is instructed by an unillustrated input setting key or the like, the CPU 14 causes the motor drive circuit 21 to start reading data at a double bit rate. By this operation, the rotation speed of the recording medium such as an optical disk is doubled as usual, and appropriate tracking operation and focusing operation are started for the laser pickup 19. Further, the CPU 14 instructs the clock generation circuit 23 to generate a clock having a frequency twice the normal frequency.

  The clock is supplied to the liquid crystal drive circuit 24 and the MPEG codec 11.

  The MPEG codec 11 decodes and outputs data at twice the normal speed. On the other hand, the liquid crystal drive circuit 24 instructs to double the display speed of the liquid crystal panel 25.

  When the display speed of the liquid crystal panel 25 cannot be changed, the liquid crystal drive circuit 24 instructs the video RAM (not shown) to thin out frames. In the case of a double bit rate, the video RAM (not shown) selects one frame for data of two frames and displays it on the liquid crystal panel 25.

  By this operation, even when the reading speed of the recording medium is increased, the display is not hindered.

  Hereinafter, the operation of the DIF 26 in the case of the double speed reproduction as described above will be described.

  When an external device is connected via the DIF26 and double-speed playback is instructed, the DIF26 performs double-speed playback for the external device connected by, for example, asynchronous communication in accordance with an instruction from the CPU 14. Notify that.

  When the external device can receive double-speed isochronous communication, the external device returns that double-speed reception is possible through asynchronous communication.

For example, AV / C Digital Interface Command Set (1394
Use CTS defined in Trade Association.

  The packetization of the isochronous packet in this case will be described below.

  The recorded data string is read out at a bit rate twice that of normal reproduction, and input to the DIF 26 for each 188-byte MPEG-TS packet.

  At this time, time stamp data is added as a header to each MPEG-TS packet to become a source packet. Next, the source packet is divided into eight data blocks as in the conventional example. Eight blocks form one isochronous data.

  This is twice as much data as the conventional example. Each isochronous data is added with a CIP header, isochronous packet header, and CRC data, and is output as an isochronous packet.

  In this example, a packet composed of 8 data blocks is transmitted in each isochronous cycle, and the bit rate of MPEG-TS data is about 12.032 Mbps.

  When the external device cannot receive the double speed isochronous communication, the external device notifies the CTS response that the external device cannot be received.

  According to the notification, the present invention displays on the liquid crystal panel 25 that the external device cannot be received.

  With the above operation, user operability can be improved.

  Hereinafter, a recording operation when the double-speed isochronous data as described above is input via DIF 26 will be described.

  First, as described above, the CTS command is used to make an inquiry about the possibility of receiving double-speed isochronous communication.

  If possible, this is notified to the transmitting device by a CTS response.

  Subsequently, the double speed isochronous data as described above is input via DIF26.

  The blocked packet data input to the DIF 26 is output to the internal bus 12 as an MPEG-TS packet with the headers deleted, as in the normal operation described above.

  On the other hand, when the double speed isochronous communication is notified by the CTS command, the CPU 14 causes the motor drive circuit 21 to start data writing at a double bit rate. By this operation, the rotation speed of the recording medium such as an optical disk is doubled as usual, and appropriate tracking operation and focusing operation are started for the laser pickup 19. Further, the CPU 14 instructs the clock generation circuit 23 to generate a clock having a frequency twice the normal frequency.

  The clock is supplied to the liquid crystal drive circuit 24 and the MPEG codec 11.

  The MPEG codec 11 decodes and outputs data at twice the normal speed. On the other hand, the liquid crystal drive circuit 24 instructs to double the display speed of the liquid crystal panel 25.

  When the display speed of the liquid crystal panel 25 cannot be changed, the liquid crystal drive circuit 24 instructs the video RAM (not shown) to thin out frames. In the case of a double bit rate, the video RAM (not shown) selects one frame for data of two frames and displays it on the liquid crystal panel 25.

  By the above operation, the recorded image can be browsed without any trouble even during double speed dubbing.

  In the present embodiment, a double example has been described. However, if the number of data blocks encapsulated in one isochronous data is increased, dubbing can be performed at higher speed. Also, the monitor display method during dubbing is only an example. Further, the recording medium is not limited to the optical disk, and a semiconductor memory or the like may be used.

  Hereinafter, the above-described CTS command and response will be described with reference to FIG. FIG. 2A shows a CTS control command format and FIG. 2B shows a response format for the control command.

  In FIG. 2A, the first field is opcode, and C6 (hexadecimal number) which is an example of the identification code of this command is stored.

  The second field (operand [0]) is a magnetic_base field, which indicates the magnification of the data rate set by the control command.

  The third (operand [1]) to the sixth (operand [4]) are magnetic_extension fields, which are used for extending the data rate magnification.

  In FIG. 2B, the first field is opcode, and C6 (hexadecimal number) which is an example of the identification code of this response is stored.

  The sixth field (operand [4]) from the second field (operand [0]) is a result field, and is a field for storing the result returned by this response.

  When a value from 02 (hexadecimal) to FE (hexadecimal) is stored in the above-mentioned magnetic_base field, for example, an integer data rate magnification is designated. In this case, for example, FFFFFFFF (hexadecimal number) is stored in the magnetization_extension field.

  In this case, the receiving device of the command discards it without using the magnetization_extension field.

  When a value of 01 (hexadecimal number) is stored in the above-mentioned magnetic_base field, for example, a value between 1.0 and less than 2 can be specified.

  In this case, for example, the magnification_extension field stores 00000001 (hexadecimal) to FFFFFFFE (hexadecimal).

  In this case, the receiving device of the command uses a value in which the value of the field is set to 1 in the denominator of the fraction in the magnetization_extension field.

  If a value of 00 (hexadecimal number) is stored in the above-mentioned magnetic_base field, for example, a value between 0 and 1 can be specified.

  In this case, for example, the magnification_extension field stores 00000001 (hexadecimal) to FFFFFFFE (hexadecimal) as described above.

  In this case, the receiving device of the command uses a value in which the value of the field is set to 1 in the denominator of the fraction in the magnetization_extension field.

  That is, a bit rate slower than usual is designated.

  When a value of FF (hexadecimal number) is stored in the above-mentioned magnetic_base field, the command receiving device discards it without using this field.

  In this case, for example, the magnification_extension field stores 000000FF (hexadecimal number) to FFFFFFFE (hexadecimal number) as described above.

  In this case, the receiving device of the command uses the value indicated in the magnetization_extension field as an integer magnification of the bit rate.

  As defined in the AV / C Digital Interface Command Set (1394 Trade Association), the control command receiving device returns a REJECT response when the control command cannot be executed.

  When a response of REJECT is returned and reception is possible at a magnification lower than the specified magnification, the receiving device returns a receivable data rate magnification using the result field. The magnification designation method in this case is the same as that of the control command.

  In other cases, when a REJECT response is returned, the receiving device returns FFFFFFFFFF (hexadecimal) in the result field.

  By configuring as described above, in the present invention, it is possible to negotiate a receivable data rate. By using this configuration, a device that transmits isochronous data can automatically determine the data rate and perform dubbing.

  In the above embodiment, only control commands are used, but it is also possible to inquire and negotiate possible data rates using the STATUS command defined in the AV / C Digital Interface Command Set (1394 Trade Association).

  In addition, when multiple receiving devices are connected, after inquiring each receiving device about its capabilities, isochronous transfer is performed according to the one with the lowest capability so that multiple copies can be made simultaneously from one master medium. Can be created.

Block diagram of an example of the configuration of the present invention Diagram showing CTS command and response used in the present invention Block diagram of an example of a conventional configuration Packetization description

Explanation of symbols

11 MPEG codec
12 Internal bus
13 DRAM
14 System control CPU
15 Error correction circuit
16 buffers
17 modem circuit
18 Playback / recording amplifier
19 Laser pickup
20 Recording media such as optical disks
21 Motor drive circuit
22 Spindle motor
23 Clock generation circuit
24 LCD drive circuit
25 LCD panel
26 Digital interface

Claims (24)

  Reading means for reading a data string recorded on a recording medium at a bit rate of an arbitrary multiple at the time of normal reproduction, and packetizing the read data string and a time stamp as a first header in the packet A packetizing means for adding a packet, a blocking means for dividing the packet into a plurality of data blocks, and a synchronous transfer of the data block and a second header different from the first header as synchronous packet data And a transmission means for transmitting the data string including the read bit rate information of the reading means.   A decoding means for decoding the data string read by the reading means; and a clock generating means for causing the decoding means to supply a decoding clock of an arbitrary frequency based on the read bit rate information of the reading means. The communication device according to claim 1.   3. The communication apparatus according to claim 2, further comprising selection means for selecting arbitrary data in the data decoded by the decoding means, and display means for displaying the selected data.   3. The communication apparatus according to claim 2, further comprising display means capable of displaying at a plurality of display frequencies, wherein the display means determines a display frequency based on a clock output from the clock generation means.   5. The communication apparatus according to claim 1, wherein the data string recorded on the recording medium is an MPEG transport stream packet.   The communication device according to claim 1, wherein the transmission unit transmits the bit rate information by asynchronous communication.   The communication apparatus according to claim 1, wherein the transmission unit transmits the bit rate information by synchronous communication.   The communication apparatus according to claim 1, wherein the transmission unit is capable of serial transmission of IEEE1394.   A communication apparatus comprising: receiving means for receiving synchronously transferred synchronous packet data; and recording means for recording a data string received by the receiving means on a recording medium at an arbitrary multiple bit rate at the time of normal recording. The receiving means receives a data string including bit rate information and outputs the data string to the recording means, and the recording means determines a bit rate at the time of recording based on the bit rate information. apparatus.   A decoding means for decoding the received synchronization packet; and a clock generation means for causing the decoding means to supply an arbitrary decoding clock based on the bit rate information received by the receiving means. The communication apparatus according to claim 9.   11. The communication apparatus according to claim 10, further comprising selection means for selecting arbitrary data in the data decoded by the decoding means, and display means for displaying the selected data.   11. The communication apparatus according to claim 10, further comprising display means capable of displaying at a plurality of display frequencies, wherein the display means determines a display frequency based on a clock output from the clock generation means.   The communication apparatus according to any one of claims 10 to 12, wherein the data string to be recorded on the recording medium is an MPEG transport stream packet.   The communication apparatus according to claim 9, wherein the reception unit receives the bit rate information by asynchronous communication.   14. The communication apparatus according to claim 9, wherein the reception unit receives the bit rate information by synchronous communication.   16. The communication apparatus according to claim 9, wherein the receiving unit is capable of receiving IEEE 1394 serial data.   Receiving means for receiving synchronously transferred synchronous packet data, recording means for recording a data string received by the receiving means on a recording medium at an arbitrary multiple bit rate during normal recording, and receiving by the receiving means A communication device comprising a decoding means for decoding the synchronized packet and a clock generating means for generating a clock of a plurality of frequencies, wherein the receiving means receives a data string including bit rate information. Output to the clock generation means, the clock generation means determines and outputs a clock frequency generated based on the bit rate information, the recording means determines a recording bit rate based on the clock, and the decoding means A communication apparatus for determining a decoding frequency based on a clock frequency.   18. The communication apparatus according to claim 17, further comprising selection means for selecting arbitrary data in the data decoded by the decoding means, and display means for displaying the selected data.   18. The communication apparatus according to claim 17, further comprising display means capable of displaying at a plurality of display frequencies, wherein the display means determines a display frequency based on a clock output from the clock generation means.   20. The communication apparatus according to claim 17, wherein the data string to be recorded on the recording medium is an MPEG transport stream packet.   21. The communication apparatus according to claim 17, wherein the reception unit receives the bit rate information by asynchronous communication.   21. The communication apparatus according to claim 17, wherein the reception unit receives the bit rate information by synchronous communication.   23. The communication apparatus according to claim 17, wherein the receiving unit is capable of receiving IEEE 1394 serial data. At least one transmitter and at least one receiver are connected on a serial bus capable of synchronous communication and asynchronous communication, and the transmitter reproduces a data string recorded on a recording medium at an arbitrary data rate. Reproduction means for performing, packetizing means for adding a first header including time information to the data string and packetizing,
Blocking means for dividing the packet into data blocks;
Synchronous packet data in which a second header different from the first header is added to the data block is synchronously transferred via the serial bus, and reproduction data rate information of the reproduction means is transmitted via the serial bus. Transmission means for
The receiver is
Receiving means for receiving the synchronous packet data and the reproduction data rate information via the serial bus;
A communication device comprising: recording means for recording the synchronization packet data on a recording medium based on the reproduction data rate information.

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