JP4089714B2 - Channel selection device and channel selection method - Google Patents

Description

The present invention relates to a channel selection device and a channel selection method for selecting and outputting necessary information from information on audio and video equipment of a plurality of channels.

  FIG. 15 is a block diagram showing a conventional multi-channel recording apparatus described in Japanese Patent Laid-Open No. 7-46522. 170 is an antenna, 172 is a distributor, 173 is a tuner, 174 is an A / D converter, and 175 is a compression. A circuit, 176 is a memory, 177 is a read circuit, 178 is a modulation circuit, 179 is a magnetic head, and 180 is a magnetic tape. In television broadcasting using terrestrial waves, video signals are AM-modulated by each broadcasting station and programs of a plurality of broadcasting stations are transmitted by frequency multiplexing.

  FIG. 16 is a diagram showing frequency occupation bands in each channel (VHF band 1 to 12 channels) of a television signal, 140 is a video carrier wave of each channel, and 141 is an audio carrier wave. Each television signal channel has a band of video carrier + audio carrier = approximately 6 MHz, and video carrier 140 and audio carrier 141 can be separated and transmitted by arranging video carrier 140 and audio carrier 141 at regular frequency intervals (4.5 MHz). It is said.

  On the reception side, multiple waves of a plurality of video signals are received by the antenna 170. This signal is distributed to the tuner 173 by the distributor 172. When receiving a video signal in real time, the tuner 173 always needs one for one broadcast. The video signal demodulated by each tuner 173 is converted into a digital signal by the A / D converter 174. In order to efficiently record this digital signal on a magnetic tape having a limited recording capacity, the data is compressed by the compression circuit 175 and then written in an area indicated by a predetermined address in the memory 176.

  A memory 176 is provided for each channel, and digital data of all channels or specific channel information can be read by the reading circuit 177. The output of the reading circuit 177 is converted (modulated) into a signal writable on the magnetic tape 180 by the modulation circuit 178 and then recorded on the magnetic tape 180 by the magnetic head 179.

FIG. 17 is a block diagram showing a conventional multi-channel playback device described in Japanese Patent Laid-Open No. 7-46522. The same reference numerals as those in FIG. 15 denote the same or corresponding parts. In FIG. 17, 82 is a demodulation circuit, 83 is an address control circuit, 84 is a decompression circuit, 85 is a D / A converter, and 86 is a TV input signal processing circuit.
The recorded information recorded on the magnetic tape 180 is reproduced by the magnetic head 179, and a reproduction signal is obtained. The reproduction signal is converted (demodulated) into a digital data signal by the demodulation circuit 82 and then stored in the memory 176 existing for each recording channel by the address control circuit 83 that controls the address of the memory 176. The reproduction data for each channel read from the memory 176 is decompressed by the decompression circuit 84 provided for each memory 176. The expanded video and audio data is converted into an analog signal by the D / A converter 85, and then a video and audio signal of a desired channel is selected from a plurality of information by the TV input signal processing circuit 86, and the TV monitor ( It is displayed as a TV program.

  In the above-described conventional example, a multi-channel transmission example of a television signal using radio waves has been described. However, when data is transferred between devices that are digital and relatively close to each other, a modulated wave that requires a large amount of power is used. It is possible to transmit a multi-channel data signal of a television signal using at least a cable. As an example, the following digital interface has been studied.

  FIG. 18 is a diagram showing a video / audio signal transfer configuration for home use, for example, using a serial interface proposed in “High Performance Serial Bus” (IEEE 1394 DRAFT 7.1) (hereinafter referred to as “IEEE 1394”). is there. In FIG. 18, 31 is a cycle start (hereinafter referred to as “CS”) signal, 32 is an isochronous (hereinafter referred to as “Iso”) data region, 33 is an asynchronous (hereinafter referred to as “Async”) region, and 34 is. VTRs 35 and 36 are TV monitors, 37 is a laser disk (hereinafter referred to as “LD”), 38 is a BS tuner, 39 is a VTR, 40 is packet data (ap 1 to ap) of a reproduced video signal from the VTR 34 to the TV monitor 35. ap3) and 41 are packet data (bp1 to bp3) of a reproduced video signal from the LD 37 to the TV monitor 36, and 42 is packet data (cp1 to cp3) of a BS video signal for recording from the BS tuner 38 to the VTR 39. In the case of IEEE 1394, the data transfer in the Iso area 32 is guaranteed to be performed once in one cycle, but the Async area 33 is irregular (sent between Iso transmissions). For example, the Iso region 32 can be used for video and audio information, and the Async region 33 can be used for control information of devices connected in accordance with IEEE1394.

  For digital video and audio signals, for example, by using signal compression / decompression technology such as Moving Picture Expert Group (hereinafter referred to as “MPEG”), the image quality of NTSC broadcasting with low-rate digital signals (about 10 Mbps) is achieved. it can. By using this MPEG technology, multi-channel data transmission can be realized with a serial data bus at a relatively low rate (about 50 Mbps). In practice, MPEG-compressed video and audio data are transmitted in units of 188 bytes called MPEG packets, so each channel data in the Iso data area 32 is composed of packet data (40 to 42 in FIG. 18). Has been.

  It is assumed that the VTRs 34 and 39, the TV monitors 35 and 36, and the BS tuner 38 are installed in different places in the home. Each device is connected via a serial data bus, and information can be freely exchanged (recording, reproduction, etc.) between them. For example, each device for displaying (reproducing) a reproduced video from the VTR 34 on the TV monitor 35, displaying a reproduced video from the LD 37 on the TV monitor 36, and recording a BS broadcast program from the BS tuner on the VTR 34. The packet data (40 to 42) indicate the output signal from. This packet data is packetized in advance by an MPEG encoder (not shown) built in each device, and this packet data is assigned to an Iso area in IEEE 1394.

  FIG. 19 is a conceptual diagram of multi-channel broadcasting using broadcasting satellites currently under study in Japan and overseas. 160 is a camera device, 161 is a VTR, 162 is a microphone, 163 is an MPEG encoder, 164 is a multiplexer, and 165 is a satellite. A receiving antenna, 166 is a channel selection device, 167 is a VTR, 168 is an MPEG decoder, 169 is a TV monitor, 271 is a modulation circuit, 272 is a demodulation circuit, and 273 is a serial bus interface.

  In FIG. 19, programs a, b, and c are produced using a plurality of camera devices 160, VTRs 161, and microphones 162, respectively. Video and audio signals from the camera device 160 and microphone 162 or VTR 161 are subjected to data compression processing by the MPEG encoder 163 for each program, and then MPEG encoded data for each program is collected in the multiplexer 164. The collected video and audio signals of each program are converted into time-division data by the multiplexer 164 and then transmitted to each home via a broadcasting satellite.

  In each home, the information received by the satellite receiving antenna 165 is recorded as it is by the VTR 167 or a necessary program (channel) is selected by the channel selection device 166. The program selected by the channel selection device 166 is decompressed by the MPEG decoder 168 and then displayed as a video on the TV monitor 169.

  In each home, a plurality of audiovisual equipment such as the satellite receiving antenna 165, VTR 167, channel selection device 166, MPEG decoder 168, TV monitor 169 can be connected via the serial bus interface 273. Information transmission between acoustic devices is possible.

  Currently, in the United States, a multi-channel broadcasting service using a satellite (12 GHz band) such as “Direct TV” has been started. “Direct TV” itself uses an original packet system that does not use MPEG packets, but is planning to move to a packet system that uses MPEG in the future, and the mainstream of multi-channel broadcasting uses MPEG packets (part 1) The configuration is shown in FIG. 19).

Japanese Patent Laid-Open No. 7-46522 (FIGS. 1 and 3)

  Since the conventional multi-channel recording / reproducing apparatus is configured as described above, even if it is desired to record a necessary program from a plurality of received program information, all other programs to be sent must be recorded. In other words, the recording medium (magnetic tape in the case of VTR) has to be used wastefully.

  In addition, the conventional multi-channel recording / reproducing apparatus must transmit all other recorded programs using a bus interface even when it is desired to reproduce a necessary program from a plurality of recorded program information. Occupying the bus interface for a long time has a drawback in that information transmission between other devices is hindered.

  Further, the conventional multi-channel recording / reproducing apparatus always supplies one decompression circuit (for example, MPEG decoded data) to all devices connected to the bus interface for compressed data (for example, MPEG encoded data) reproduced from the recording / reproducing apparatus. ) Had to be provided.

The present invention has been made to solve the above-mentioned problems, and obtains a channel selection device and a channel selection method for outputting in a format capable of efficiently recording and reproducing after selecting necessary program information. For the purpose.

A channel selection device according to the present invention comprises channel selection means for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels, means for generating predetermined time data, and the time data as the channel A time stamp adding means for adding to the packet data outputted from the selecting means and outputting the packet data. The channel selecting means is added to a predetermined position of the transport stream and corresponds to the contents of the program of each channel. The packet data is extracted based on the information value.

A channel selection method according to the present invention is a channel selection method for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels, and is added to a predetermined position of the transport stream, Extracting the packet data based on information values corresponding to the contents of the program, generating predetermined time data, adding the generated time data to the extracted packet data, and outputting the data.

A channel selection device according to the present invention comprises channel selection means for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels, means for generating predetermined time data, and the time data as the channel A time stamp adding means for adding to the packet data outputted from the selecting means and outputting the packet data. The channel selecting means is added to a predetermined position of the transport stream and corresponds to the contents of the program of each channel. Since the packet data is extracted based on the information value, it can be output in a format that can be efficiently recorded and reproduced after selecting necessary program information.

A channel selection method according to the present invention is a channel selection method for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels, and is added to a predetermined position of the transport stream, Extracting the packet data based on an information value corresponding to the contents of the program, generating predetermined time data, and adding the generated time data to the extracted packet data for output. After the necessary program information is selected, it can be output in a format that can be efficiently recorded and reproduced.

  In a recording / reproducing apparatus described below, a time stamp is added to an arbitrary program from a plurality of channels and selected and output.

  In addition, an absolute time or a relative time with respect to the timer device or an elapsed time from the previous time stamp is added as a time stamp to an arbitrary program from a plurality of channels, and then selected and output.

  The transport packet is recorded with a time stamp added.

  In addition, a transport packet to which the absolute time, relative time and elapsed time from the previous time stamp for the timer device are added as a time stamp is recorded.

  Also, after separating the time stamp from the reproduction data, time axis conversion is performed.

  The transport packet is recorded and reproduced with a time stamp added.

  Further, the output of the time axis converter and the transmission path data to be output at the time indicated by the time stamp information are selected and output to the channel selector.

  A channel selector that selects the output of the time axis converter and the transmission path data to be output at the time indicated in the time stamp information composed of the absolute time, the relative time and the elapsed time from the previous time stamp for the timer device. Output to.

  Further, a second time stamp is added to the input packet data and recorded.

  In addition, a second time stamp identical to the first time stamp is added to the input packet data and recorded.

  In addition, necessary programs are selectively recorded.

  Further, the recording rate is varied according to the data rate of the data to be recorded.

  Also, one packet is divided and transmitted according to the rate of data to be transmitted.

  Data compression processing is performed on the packet data input from the transmission path, and the compressed data is output to the transmission path.

  Further, data expansion processing is performed on the packet data input from the transmission path, and the expanded data is output to the transmission path.

Example 1.
A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 1 is a satellite broadcast decoder, 2 is a channel selector, 3 is a bus interface, 4 is a hard disk drive (hereinafter referred to as “HDD”), 20 is a receiving antenna, 27 is an MPEG decoder, 28 is a TV monitor, 50 is a first time axis converter, 51 is a timer device, 52 is a time stamp adder, 53 is a second time axis converter, 60 is a third time axis converter, 100 is a channel selection device, and 101 is a recording / reproducing device. It is. FIG. 2 is a diagram showing transmission data of the first embodiment, in which 5 is a time stamp, 24 is a header, 32 is an Iso area, and 33 is an Async area.

  Next, the operation will be described. FIG. 1 shows a circuit configuration for selecting and recording a specific program for satellite broadcasting in which a program of a plurality of channels is transmitted. Video signals of programs of a plurality of channels sent from a broadcasting satellite (not shown) are modulated and transmitted for transmission via the satellite. This signal is demodulated by the satellite broadcast decoder 1 and converted into a bit stream signal in units of one packet 188 bytes as shown in FIG. FIG. 3 shows a packet configuration in the bit stream signal shown in FIG.

  In FIG. 3, 6 is a Program Association Table (hereinafter referred to as “PAT”), 7 is a Packet Identification (hereinafter referred to as “PID”), 8 is a Program Map Table (hereinafter referred to as “PMT”), and 9 is an Adaptation. Field (hereinafter referred to as “APF”), 10 is a Peak Rate Flag (hereinafter referred to as “PRF”), 11 is an Audio packet, 12 is a Video packet, and 21 is a Network Information Table (hereinafter referred to as “NIT”). , 22 is a Conditional Access Table (hereinafter referred to as “CAT”).

  Multi-channel broadcasting is composed of a data stream of 188 bytes packet unit called MPEG2 transport stream (hereinafter referred to as “TS”). Each packet constituting the TS is assigned with PID (13 bits) as identification information unique to the packet, whereby the information content of the packet can be identified or searched. For example, since a unique numerical value such as PID = "00" is assigned to PAT6 in FIG. 3 and PID = "03" is assigned to PMT-0, only the necessary packets are selected and extracted by detecting only the PID. It is also possible to do.

  Information indicating the start of the multi-channel program is described in a packet called PAT6. For example, as shown in FIG. And information indicating the relation between the PID value of the PMT 8 corresponding to the program. This PAT6 is followed by a packet in which various information such as NIT21 and CAT22 is described. Following these packets are PMT8 (PMT-0 to PMT-2) information packets (for example, genre categories such as Video, Audio, Data, etc.) for each program and packets indicating the relationship between PIDs. For example, as shown in FIG. 3B, information such as PID = “2F” is written in the audio data and PID = “35” is written in the video data in the program0. FIG. 3C shows the contents of PMT8 (PMT-1) in program1, and information is written in the same manner as PMT-0.

  The PMT 8 always has one packet corresponding to each program, and PMTs 8 of the number of transmitted programs are continuously arranged. In the subsequent APF 9 (APF-0), information necessary for MPEG2 decoding of actual information (data packets such as Audio and Video) of each program is written. This includes a PRF 10 indicating the peak rate at the time of MPEG2 encoding for each program. By detecting this PRF 10, the maximum data rate of the transmitted program can be detected.

  After the APF 9 (APF-0), the audio packet 11 and the video packet 12 are continuously arranged for the number of packets required for each program. After all the information of program0 is transmitted, APF9 (APF-1) of program1 is transmitted as shown in FIG. 3D, and thereafter, the audio packet 11 and the video packet 12 are continuously transmitted as in the case of program0.

  In the bit stream signal of the multi-channel broadcasting shown in FIGS. 2A and 3, only the necessary information channel is selected by the channel selector 2 shown in FIG. (For example, one conforming to IEEE 1394). In this bus interface 3, as shown in FIG. 2B, a cycle (for example, about 50 Mbps) is higher than the bit stream signal of multi-channel broadcasting (FIG. 2A) on the basis of 125 μs per cycle by the CS signal 31. ) Transmission is performed. One packet (188 bytes) of a bit stream signal of multi-channel broadcasting is transmitted in the form of rate conversion to the Iso area 32 as shown in FIG.

  In the HDD 4 shown in FIG. 1, in order to record a multi-channel broadcast bit stream signal from the channel selector 2 via the bus interface 3, the HDD 4 sends the channel selector 2 to the bus interface 3 in advance. Requests that information be output. For this request, the channel control information such as what program information is requested for the multi-channel broadcast from the channel selector 2 on the HDD 4 side, for example, the async area 33 set in the bus interface 3 in advance. Or the like is transmitted to the channel selector 2. In response to this request, information is transmitted via the bus interface 3 as described above.

  At the time of this transmission, in addition to the bit stream signal of the multi-channel broadcast, as shown in FIG. 2 (b), data having contents indicating which device the information is transmitted from the channel selector 2 is used as the header 24. After being added, the data is output to the bus interface 3. The HDD 4 always detects the header 24 added to all information transmitted through the bus interface 3, and extracts this information from the bus interface 3 when it is detected that the information is addressed to itself. Perform the recording process.

  FIG. 4 is a diagram illustrating a data processing process in which, for example, a program in a bit stream signal of multi-channel broadcasting is set to programs 0 to 2 and information on program 0 received by the HDD 4 is recorded. FIG. 4A shows an example of transmission of actual program information (program0 to program2). Here, the information unit of program 0 (hereinafter referred to as “1 block packet”) is 188 × n (n ≧ 1, n is a natural number), and the information unit of program 1 is 188 × m (bytes) (m ≧ 1, m is Natural number) and program2 information units are defined as 188 × k (bytes) (k ≧ 1, k is a natural number).

  For the bit stream signal from the satellite broadcast decoder 1 in FIG. 4 (a), the channel selector 2 selects only the necessary information channel (only program 0 in this embodiment) as shown in FIG. 4 (b). To the bus interface 3.

  Transmission channel information from the bus interface 3 is input to the first time axis converter 50 in the signal form as shown in FIG. Here, in the signal shown in FIG. 4C, only the program 0 is extracted by detecting the header in the transmission channel information from the bus interface 3 as described above, and other program information is ignored. Is done. The timer device 51 has a 24-hour reference counter, and generates digital data representing the time when the information of program0 arrives at the first time axis converter 50 as a time stamp of 4 (bytes), for example.

When program 0 information is received by the HDD 4, information is sent in units of 188 × n packets as shown in FIG. 4C, but the transmission time other than one block packet (period shown by 26 b in FIG. 4C) ) Is a time that has no meaning as information. Therefore, when the program 0 is recorded in the HDD 4, the time stamp 5 is added to the signal obtained by shortening the transmission time 26b by the first time axis converter 50 constituted by a buffer or the like in the time stamp adder 52, and FIG. The signal in the state d) is input to the HDD 4. Thus, by reducing the transmission time other than one block packet by the first time axis converter 50 and lowering the data rate of one block packet information, the recording rate in the HDD 4 can be lowered, and the access time of the HDD 4 is delayed. The device can be made at low cost. That is, compared with the case where data is written in real time for the period 26a, it is only necessary to write the same amount of data for the period (26a + 26b), so that the access time can be made much slower. It can be used.
Further, in the case of recording to a tape data device instead of the HDD 4, for example, if the recording speed is adjusted to the period of 26a, it leads to wasteful tape consumption for the period of 26b when there is no program information to be recorded. As described above, by recording the program information of the period 26a in the time of (26a + 26b), it is possible to avoid the occurrence of problems such as a decrease in the recording time as a whole. Needless to say, as with the HDD 4, an inexpensive tape device with a low recording rate can be used.

  Note that the change in the recording rate and the movement of the block packet along the time axis have a significant effect on the MPEG decoding process during reproduction. This is because, when decoding MPEG data, the arrival time of the packet itself is required, but this time axis conversion (time axis movement) destroys the relationship between the packet arrival times during the recording and reproduction processes. by. In order to avoid this problem, by adding a time stamp 5 indicating a reference time, for example, an absolute time for the timer device 51, to each packet (188 bytes), a time stamp inherent in MPEG2 (set in each block packet). )) Can be corrected. That is, the time stamp data may be referred to at the time of decoding and reproduced in accordance with the original arrival time for each packet.

  Next, the conversion rate for time axis conversion is determined as follows. When recording on the HDD 4, the peak data rate at the time of MPEG2 encoding of program 0 is detected by detecting the PRF 10 from the program information in FIG. 4D, and the recording rate of the HDD corresponding to this value is set. For example, when PRF = “10”, this indicates that the peak data rate is 10 Mbps, and the optimum recording rate to the HDD 4 is set from this value. In the present embodiment, for example, it is assumed that PRF = “6”, that is, the peak rate is 6 Mbps. Therefore, the data rate at the time of recording on the HDD 4 in the state shown in FIG. 4D is set to 6 Mbps.

  This is particularly important when a tape device is used as the recording device, and indicates the minimum tape running speed that can be recorded completely. If the recording rate is increased more than necessary, the tape is wasted, resulting in a shortened recording time. On the other hand, if the recording rate is too low, data that cannot be recorded is generated. Therefore, the most reasonable recording can be realized by selecting a tape running speed that enables the minimum necessary data recording.

  In the above description, the time stamp is added based on the time at which the channel information arrives at the first time base converter 50. However, this time may be performed at any stage before it is recorded in the HDD 4. Good. For example, as will be described later in detail, as shown in FIG. 7, after adding a time stamp with the timer device 51 and time stamp adder 52 based on the time immediately after channel information selection in the channel selector 2, the bus interface 3 may be output. In this case, a time stamp of 4 bytes, for example, may be added to the bus interface 3 and transmitted in units of 1 packet = 188 + 4 = 192 bytes.

  The time stamp information may be the absolute time itself indicated by the timer device 51, the relative time from a specific time point, or the time interval value from the previous packet arrival time. Of course, in any case, the packet arrival time during reproduction can be easily restored.

  In the above description, 4 bytes are secured as an example of the time stamp value. However, this is made possible to count for 1 hour with 1 MHz accuracy, and is sufficient for normal use. . However, the data length of the time stamp need not be particularly limited to 4 bytes. If the accuracy may be coarse, the number of bytes of the time stamp value may be reduced, and if the accuracy is insufficient, it may be increased. Needless to say, the same effect can be achieved.

  The case where the program 0 information is recorded on the HDD 4 has been described above. The reproduction process from the HDD 4 is as follows. The program information reproduced from the HDD 4 constitutes a bit stream having a block packet structure as shown in FIGS. This bit stream signal from the HDD 4 is subjected to time axis movement (conversion) such as rate conversion by the second time axis converter 53 shown in FIG. 1 and to the third time axis converter 60 via the bus interface 3. Therefore, the program 0 information of one block packet is transmitted (output) in units of, for example, one packet (188 + 4 (time stamp) = 192 bytes) for one cycle (125 μs).

  The third time axis converter 60 receives the block packet as shown in FIG. 5D through the serial interface 3 and performs time axis conversion on this signal, as shown in FIG. 5E. To an MPEG2 packet signal. The received packet (192 bytes) is corrected by the 4-byte time stamp 5 added at the time of recording to correct the deviation of the arrival time of the packet to the HDD 4 at the time of recording, and then each block packet defined by the MPEG2 format. By decoding MPEG2 using the time stamp included therein, the information of program0 can be reproduced as video and audio signals. The output of the MPEG2 decoder (program 0 video and audio signals) can be reproduced as video and audio information by the TV monitor 28.

  In the above description, the hard disk drive (HDD) is used for recording and reproducing program 0 information. However, the present invention is not limited to this. For example, DDS (digital data storage) or D8 computer backup recording Needless to say, any medium that can be recorded and reproduced, such as a reproducing apparatus, may be used.

  Further, in the above description, transmission of multi-channel broadcasting using satellite broadcasting is taken as an example. However, the transmission is not limited to satellite broadcasting, and multi-channel broadcasting from terrestrial, CATV (cable TV), or other transmission means. Needless to say, the same configuration can be realized.

  In the above description, the PRF 10 is provided in the APF 9, but if it can be set for each program at the time of recording, it is not necessary to provide it in the APF, and it may be written in another area.

  Further, in the above description, the recording rate of the HDD 4 is determined by the PRF 10 indicating the peak rate. However, the recording rate is not limited to the peak rate, and the recording rate may be determined using an average data rate or the like.

  In the above description, the recording rate of the HDD 4 is determined by the PRF 10 indicating the peak rate. For example, even when the peak rate information is not obtained during MPEG2 encoding, the number of program 0 packets received by the HDD 4 is determined. By counting, the average data rate at the time of MPEG2 encoding can be calculated, so the recording data rate of the HDD 4 can be set from this value. This is shown in FIG.

  FIG. 6 is a block diagram showing a configuration in which the recording data rate is recorded by setting the recording data rate and the tape traveling speed by a VTR which is a recording device similar to the HDD 4, for example. In FIG. 6A, the same reference numerals as those in the conventional example or the first embodiment denote the same or corresponding parts.

In FIG. 6A, 70 is a VTR, 71 is a packet counter, and 72 is a recording rate controller.
The packet data from the bus interface 3 is subjected to time axis shift and data rate conversion by the first time axis converter 50 as in the first embodiment. On the other hand, for the input packet data, the packet counter 71 counts the number of packets per unit time. The count value of the number of packets serves as a reference for the transfer rate of the input packet data, and the first time axis converter 50 performs data rate conversion based on the count value. The output of the first time axis converter 50 is recorded on a tape (not shown) by the VTR 70 after adding a time stamp by the time stamp adder 52 as in the first embodiment.

  The recording rate controller 72 calculates a necessary recording data rate based on the count value of the number of packets from the packet counter 71, and controls the tape running speed of the VTR 70 based on the calculated recording data rate. Here, FIG. 6B is a diagram showing the relationship between the input data recording rate and the recording time with respect to the tape running speed. When the relationship of the tape speed is speed3> speed2> speed1, the data decreases as the tape speed decreases. Although the rate decreases, the recording time increases.

Example 2
In the first embodiment, the time stamp 5 indicating the arrival time of the packet is added in the recording / reproducing apparatus 101. However, the time stamp 5 can also be performed on the selection apparatus 100 side. The configuration of the second embodiment is shown in FIG. In FIG. 7, the same reference numerals as those of the conventional example or the first embodiment denote the same or corresponding parts.

  Now, when data is transmitted from the channel selection device 100 to the recording / reproducing device 101, it is assumed in the first embodiment that transmission in real time is possible. However, there are many cases where this is not the case in reality. That is, when it is desired to transmit data from the channel selection device 100, the bus interface 3 may be occupied by another device (not shown), or the recording / reproducing device 101 itself may not be receivable. is there. When such a situation occurs, as previously described in the first embodiment, time fluctuation (displacement) occurs in the arrival of the packet to the recording / reproducing apparatus 101. Therefore, an accurate arrival time is set. I can't know. Therefore, this problem can be avoided if a time stamp indicating the arrival time is added by the channel selection device 100 before data is transmitted to the bus interface 3.

  On the recording / reproducing apparatus 101 side, a time stamp is already added to each packet, so that the timer apparatus 51 is not necessary. The time stamp is discriminated by the time stamp discriminator 57 and the time stamp suitable for the recording / reproducing apparatus 101 is obtained. You only need to do the conversion to format. Of course, the input time stamp may be recorded as it is.

  A description of the time axis converter is added here. The time axis converter converts the input data rate and the output data rate. For example, a FIFO (First In First Out) memory is used, and the writing and reading speeds are determined according to the input data rate and the output data rate, respectively. Configured. Of course, other types of memory or the like may be used to perform data writing and reading at different speeds.

Example 3
A third embodiment of the present invention will be described below with reference to FIGS. FIG. 8 is a block diagram showing a circuit configuration of the third embodiment, and FIG. 9 is a diagram showing a data transmission process. 8 and 9, the same reference numerals as those of the conventional example or the first and second embodiments denote the same or corresponding parts. FIG. 9A shows a bit stream of multi-channel satellite broadcasting similar to FIG. 4A of the first embodiment.

  In FIG. 8, it is assumed that the multi-channel bit stream signal output from the satellite broadcast decoder 1 has selected, for example, program 0 and program 1 (2 channels) by the channel selector 2. The 2-channel program signal from the channel selector 2 is transmitted in units of packets in each cycle on the bus interface 3 as shown in FIG. 9B. The HDD 4 side requests the channel selector 2 to transmit the 2-channel program in advance using, for example, the async area 33 of the bus interface 3, and the first time axis converter 50 as shown in FIG. Receive correct data. Then, the time axis movement is performed on the received data as in the first embodiment. On the other hand, the time stamp adder 52 generates the time stamp 5 based on the time information from the timer device 51 in consideration of the decoding by the MPEG2 system at the time of reproduction, and the output of the first time axis converter 50 is Add a time stamp. Then, two-channel recording is performed in the same manner as the one-channel program recording described in the first embodiment.

  Here, in the case of 2 program (2 programs) recording, if the start time and the end time of program 0 and program 1 are the same, the recording rate of HDD 4 may be kept constant, but the end time of one program is the same as the other program. If it is earlier (for example, when a baseball broadcast and a drama program with the same broadcast time are recorded simultaneously, if the baseball broadcast ends earlier than the scheduled end time), the recording rate of the HDD 4 is set after one program ends. The recording is continued to the end time of the program, for example, by halving the 2 program recording.

  In the above description, after one program is completed, the recording rate is reduced to ½ until the other recording is finished. However, this recording rate is not limited to ½, The recording rate of the other program may be determined according to the remaining recordable capacity of the HDD 4 at the time when the program ends.

  At the time of reproduction, the reproduction data from the HDD 4 is sent to the bus interface 3 as in the first embodiment. In this embodiment, 2-channel information is transmitted on the bus interface 3. For example, when the 2-channel information is both video and audio data, reproduction information is output from the TV monitor 28. However, since information on two channels is transmitted on the bus interface 3, it is necessary to select one channel by the second channel selector 54. The information thus selected is subjected to time axis conversion and reproduction rate conversion by the third time axis converter 60 and then converted to video and audio information that can be viewed on the TV monitor 28 by the MPEG decoder 27.

  Note that the processing order of the second channel selector 54 and the third time axis converter 60 is not limited to this example, and it is obvious that the same effects as in the present embodiment can be obtained even if they are switched. FIG. 10 shows a configuration example in which the configuration of the channel selection device in FIG. 8 is simplified.

  FIG. 10 shows a case where the channel selector 2 and the second channel selector 54 in FIG. 8 are shared by a single channel selector 2, and when receiving satellite broadcast and reproducing the output from the recording / reproducing apparatus. The switch 130 is used by switching. With this configuration, it is possible to reduce the number of channel selectors compared to the same device in FIG. 8, and it is possible to create a device having the same function as the previous example at a very low cost.

Example 4
The fourth embodiment of the present invention will be described below. In the AFP 9 in FIG. 4, information (peak rate, program information, etc.) for each program can be set as described in the first embodiment. For example, a program category bit 26 of 4 bits (0 to 15) is set as program information as shown in FIG. The program category bit 26 is set such that “0” is drama, “1” is sport,..., “7” is concert, “8-15” is other, and so on. When channel selection is performed by the first channel selector 2, the APF 9 of each program is detected, and the program category bit 26 added thereto is detected.

  As a program selection method, as a method of recording only a specific program genre (for example, only a movie) from multi-channel broadcasting, only a program in which the program category bit 26 indicates “2” may be selected and recorded. As an implementation method, for example, a circuit for extracting a category bit and a circuit for determining whether the category bit extracted by the circuit is equal to a desired category value are provided. It may be configured to output the PAT and otherwise block the output, and can be easily realized without technical difficulties. The program of the movie program selected by the first channel selector 2 can be recorded and reproduced by the same method as in the first or second embodiment.

Example 5 FIG.
Embodiment 5 of the present invention will be described below. 12A is an ideal MPEG packet transmission state, FIG. 12B is a transmission state on the bus interface 3, and FIG. 12C is a transmission state when the generation of MPEG packets is irregular, FIG. 12 (d) shows a transmission state on the bus interface 3 corresponding thereto, and FIG. 12 (e) shows a transmission state on the bus interface 3 when one packet in FIG. 12 (c) is divided into four.

  As described in the first embodiment, the multi-channel program transmission method includes the bit stream signal received by the satellite broadcast decoder 1 of FIG. In the ideal bit stream signal, each packet is regularly transmitted as shown in FIG. Such a bit stream signal is transmitted to the bus interface 3 as shown in FIG. 12B and is efficiently transmitted on the bus interface 3.

However, the transmission form of the MPEG packet on the bit stream signal is not actually transmitted regularly with respect to the time axis as shown in FIG. 12 (c). Depending on the content of the voice information, there are irregularly distributed time zones in which packets are concentrated and distributed time zones. FIG. 12 (d) shows the transmission on the bus interface 3 in this state.
As can be seen from this signal, if the signal of FIG. 12C is transmitted to the bus interface 3 as it is, there is no information to be transmitted on the bus interface 3 in a time zone where no MPEG packet exists. .

  By the way, regarding the use of the bus, a procedure of bandwidth reservation is taken in advance so that data transfer can be performed stably at all times. For example, in the state of FIG. 12B, it is guaranteed that 188-byte data is transmitted once every basic cycle (125 μs) of the bus interface 3.

  However, if an excessive bandwidth is reserved at this time, the entire bus is wasted. For example, the cycle in which nothing is transmitted in FIG. When bandwidth reservation is made for the capacity of the entire bus, it cannot be used even if there is another device to be used (even if there is an empty cycle).

  In this way, it is very important to share and use the bus capacity efficiently, including other devices. Therefore, it is necessary to make a minimum bandwidth reservation for data transmission, and in this way, many devices can share the bus. For this purpose, for example, as shown in FIG. 12 (e), one packet may be divided into four and transmitted sequentially in each bus cycle. Prior to transmission on the bus interface 3, the channel selector 2 divides one MPEG packet into four and sequentially transmits each 1/4 packet every bus cycle (125 μs). In this way, the bandwidth reservation of the bus interface 3 is ¼ compared with the case where transmission is performed for each packet, and it is possible to greatly contribute to effective utilization of bus resources.

  FIG. 12 (e) shows one packet of FIG. 12 (c) divided into four and then transmitted onto the bus interface 3. In this processing, before transmission onto the bus interface 3, that is, the MPEG1 packet data is divided into four by the channel selector 2, that is, data is selected every 1/4 packet.

  In the above description, the case where one packet is divided into four has been described, but the number of divisions is determined by the transmission state (packet density) of the MPEG packet on the bit stream. As this reference, the optimum division number is determined based on the average data rate (the number of packet transmissions per unit time) described in the first embodiment or the PRF 10 indicating the peak rate.

Example 6
A sixth embodiment of the present invention will be described below with reference to FIG. In FIG. 13, the same reference numerals as those of the conventional example or each embodiment denote the same or corresponding parts. In FIG. 13, 56 is an expansion circuit, 61 is a fourth time axis converter, 68 is a fifth time axis converter, and 102 is an expansion device.
The multiple channel information received from the satellite antenna 20 is demodulated by the satellite broadcast decoder 1 and converted into a bit stream signal having multiple channel information. The necessary channel information is selected from this signal by the channel selector 2 and then sent to the bus interface 3. The channel selector 2 first transmits the selected channel information a to the fourth time axis converter 61. The fourth time axis converter 61 converts the data rate of the original channel information from the bus interface 3 and moves the time axis. Since the output of the fourth time base converter 61 is a normal MPEG packet signal, it is converted into a baseband digital video and audio signal by a decompression circuit 56 (for example, an MPEG2 decoder).

  From the decompression circuit 56, the digital video and audio signals returned to the baseband signal are sent to the bus interface 3 via the fifth time axis converter 68. The transmitted baseband digital video and audio signal b is time-axis shifted and data rate converted by the first time-axis converter 50 and then recorded on the HDD 4. The recorded baseband digital video and audio signals can be viewed on the TV monitor 28 via the second time axis converter 53, the bus interface 3, and the third time axis converter 60, as in the first embodiment.

  Further, the baseband digital video and audio signals (uncompressed video and audio data) c sent to the bus interface 3 are directly received by the third time axis converter 60 to perform time axis movement and data rate conversion. After that, it can be viewed on the TV monitor 28.

  With this configuration, for example, an MPEG2 video disk device or VTR device can be directly connected to the bus interface 3 in the system of FIG. That is, it is not necessary for these devices to have an MPEG2 decoder, and as a result, individual MPEG2 signal reproduction devices and television devices can be manufactured at low cost.

  If only one decoder having MPEG2 stream input and baseband output devices is prepared on the bus interface 3, it can be effectively used by other devices. As the capacity of the bus interface 3, for example, if IEEE1394 is used, a data transmission capacity of 400 Mbps can be easily realized. Therefore, even if the baseband is exclusively used for one system (about 170 Mbps for the current TV signal), the remaining transmission capacity is used. By transmitting MPEG2 data (10 Mbps), 23 systems can be transmitted (only 2 systems can be transmitted in the case of baseband transmission). Here, the decompression circuit 56 itself in the decompression device 102 in FIG. 13 has already been realized as described in, for example, Nikkei Electronics 1995.5.8 pages 165 to 174. A decompression circuit can also be used in this apparatus. Rather, if a system that has already been put into practical use and used widely like MPEG2 is used, it is possible not only to produce a device at a low cost due to mass production effects, but also because it has a large number of devices to be connected, it has the advantage of being highly versatile. There is an effect that it is very much.

As described above, if the expansion device 102 shown in FIG. 13 is used in common for each device connected to the bus interface, the transmission capacity of the bus interface can be used effectively, and it is necessary to provide an expansion circuit for each device individually. Therefore, the cost can be kept low, and the system can be easily constructed.
In the sixth embodiment, the case where MPEG2 is used as the decompression apparatus 102 has been described. However, the present invention is not limited to this, and it is obvious that the same effect can be obtained even if other methods are used.

  In the sixth embodiment, the decompression apparatus 102 has been described. However, only one compression apparatus needs to exist on the bus interface 3.

  That is, when compressing uncompressed video (baseband video) to MPEG2, for example, it is not necessary to incorporate a compression device in each device (for example, VTR) that performs MPEG2 recording. The device can be manufactured at a very low cost.

  FIG. 14 is a diagram showing the configuration of the compression device and the expansion device. The configuration itself of the compression device 103 can be realized by replacing the expansion circuit 56 in the expansion device 102 of FIG. 13 with a compression circuit 81 and providing a timer device 51 and a time stamp adding device 52. In addition, 69 is a 6th time-axis converter, 80 is a 7th time-axis converter. The compression apparatus itself has already been put into practical use, for example, as described in Nikkei Electronics 1995.5.8, pages 165 to 174. For example, such a compression apparatus can also be used for this apparatus. In addition, if a method that has already been put into practical use and used widely like MPEG2 is used, not only can the device be produced at low cost due to mass production effects, etc., but there are also many devices that can be connected, so it is highly versatile. There is an effect that there are very many.

  According to the recording / reproducing apparatus and the like described above, only necessary information is selected from information of a plurality of channels and then recorded on the recording / reproducing apparatus, so that other unnecessary information of the plurality of channels is recorded. There is no need. As a result, the recording medium can be used effectively, and unnecessary information is not transmitted to the bus interface, so that it is possible to reduce the influence that prevents information transmission between other devices connected to the bus interface. That is, the transmission efficiency of the bus interface can be increased. Furthermore, even when data transmission time fluctuates during bus transmission, the time stamp makes it possible to use it and connect to various buses.

  In addition, since only the program information of a required genre can be selected and recorded from the information of a plurality of channels, the search time for required information can be greatly shortened.

  Further, the most efficient form as the time stamp data can be specifically adopted, and there is an effect that the hardware scale can be reduced, the price of the apparatus can be reduced, and the selection range of the connection partner device can be widened.

  In addition, since the time stamp recording function is provided, it is possible to realize the uniform rate recording by averaging the recording of data whose input timings are not equally spaced, so that it is not necessary to use an expensive apparatus for the peak speed recording. Thus, it is possible to produce at a low cost, and as a result, it is possible to increase the recording time.

  Further, the most efficient form as the time stamp data can be specifically adopted, and there is an effect that the hardware scale can be reduced, the price of the apparatus can be reduced, and the selection range of the connection partner device can be widened.

  In addition, when playing back data with a time stamp, other equipment can make playback exactly the same as the signal state at the time of recording by making the playback data output timing the same as that at the time of input according to the time stamp value. There is an effect that complete compatibility with can be achieved.

  In addition, by using the same device as the same device, there is a synergistic effect such that recording and reproduction can be performed independently. It should also be noted that many circuits and parts, such as an interface circuit for recording / reproducing media, can be used together, so that the production of a device that is much cheaper than that of a device that separates recording and reproduction is possible. There is an effect that becomes possible.

  In addition, since it is configured to use a channel selector also when connecting to recording / reproducing equipment with multiple channels, not only can the device be produced at a low cost, but one operation of switching the selector can be performed with on-air broadcasting. There is an effect that the playback signal can be easily switched.

  Further, the most efficient form as the time stamp data can be specifically adopted, and there is an effect that the hardware scale can be reduced, the price of the apparatus can be reduced, and the selection range of the connection partner device can be widened.

  Further, since the timer device is not required as compared with the present invention, there is an effect that an optimal time stamp format that can provide a very inexpensive device can be used.

  Also, since the input time stamp is used for recording as it is, there is an effect that it is not necessary to create a time stamp and it is possible to provide a cheaper apparatus.

  In addition to the effect of the invention of claim 1, there is an effect that a related program can be easily selected.

  Further, when information on a plurality of channels is recorded simultaneously, all desired information can be recorded regardless of the end time of each channel information.

  Further, since the recording rate of the recording apparatus can be automatically set from the data rate of the information to be recorded, complicated processing for determining the recording rate can be simplified, and efficient recording to the recording apparatus can be performed.

  In addition, since one packet can be transmitted with the optimum number of divisions according to the transmission form (peak data rate or average data rate) of packet information to be transmitted, the influence on transmission between other devices is reduced. The transmission efficiency of the bus interface can be increased.

  In addition, since only one compression device is required for a plurality of devices connected to one bus interface, the cost of each device can be greatly reduced.

  In addition, since only one decompression device is required for a plurality of devices connected to one bus interface, the cost of each device can be greatly reduced.

It is a block diagram which shows the structure of Example 1 of this invention. It is a figure which shows the transmission data in Example 1. FIG. It is a figure which shows the detail of the satellite bit stream in Example 1. FIG. 6 is a diagram illustrating a data processing process during recording in Embodiment 1. FIG. FIG. 6 is a diagram illustrating a data processing process during reproduction in the first embodiment. FIG. 3 is a block diagram showing a configuration when recording is performed by setting a recording data rate and a tape running speed for the VTR in the first embodiment. It is a block diagram which shows the structure of Example 2 of this invention. It is a block diagram which shows the structure of Example 3 of this invention. FIG. 10 is a diagram illustrating a data transmission process in the third embodiment. FIG. 10 is a block diagram illustrating another configuration example according to the third embodiment. It is a figure which shows the program category bit in Example 4 of this invention. It is a figure which shows the data transmission process in Example 5 of this invention. It is a block diagram which shows the structure of Example 6 of this invention. It is a block diagram which shows the structure of Example 6 of this invention. It is a block diagram which shows the conventional multichannel recording device. It is a figure which shows the frequency occupation band in each channel (VHF band 1-12 channel) of a television signal. It is a block diagram which shows the conventional multichannel reproducing | regenerating apparatus. It is a figure which shows the transfer structure of the video / audio signal using a serial interface. It is a conceptual diagram of multi-channel broadcasting.

Explanation of symbols

  2 1st channel selector, 3 bus interface, 4 HDD, 5 time stamp, 27 MPEG decoder, 50 1st time base converter, 51 timer device, 52 time stamp adder, 53 2nd time base converter, 54 1st time base converter 2-channel selector, 56 expansion circuit, 60 third time axis converter, 61 fourth time axis converter, 68 fifth time axis converter, 69 sixth time axis converter, 80 seventh time axis converter, 81 Compression circuit, 100 channel selection device, 101 recording / playback device, 102 decompression device, 103 compression device, 130 switch.

Claims (2)

Channel selection means for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels;
  Means for generating predetermined time data;
  Time stamp adding means for adding the time data to the packet data output from the channel selecting means and outputting the packet data;
  The channel selection device configured to extract the packet data based on an information value added to a predetermined position of the transport stream and corresponding to the content of a program of each channel. A channel selection method for extracting a predetermined transport packet included in a transport stream composed of packet data of a plurality of channels,
  Extracting the packet data based on an information value added to a predetermined position of the transport stream and corresponding to the content of the program of each channel;
  Generate predetermined time data,
  A channel selection method, wherein the generated time data is added to the extracted packet data and output.

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