JP3897753B2 - Memory output device - Google Patents

Description

  The present invention relates to a technique for storing and outputting a plurality of continuous data.

For example, MPEG2 (Moving Picture Experts
A transport stream (hereinafter abbreviated as “MPEG2-TS”) in which video data is multiplexed according to the GroupPhase 2) standard includes transport packets as a plurality of continuous data. Video recording / reproducing apparatuses that record and reproduce transport packets in the MPEG2-TS are known (Patent Documents 1 to 3).

JP2003-324690A. JP2003-9085A. JP 2002-354419 A.

  In MPEG2-TS, transport packets including received video data are multiplexed. Therefore, in MPEG2-TS, transport packets of an arbitrary channel are continuous at intervals, and the empty packets are transmitted. One or a plurality of other-channel transport packets exist in the interval. For this reason, when only an arbitrary transport packet in MPEG2-TS is extracted and recorded on a hard disk or displayed on a display screen, appropriate control is required, and how to perform the control is a problem. It becomes.

  Such a problem may also exist when recording and outputting a plurality of other types of continuous data.

  Accordingly, an object of the present invention is to appropriately control recording and outputting a plurality of continuous data.

  Other objects of the present invention will become clear from the following description.

  The storage output device according to the present invention adds an acquisition means for acquiring each of a plurality of continuous data, and adds a special time stamp representing information on a temporal position of the data to each of the acquired plurality of data. Reading means for storing in the storage means, and reading each of a plurality of stamped data that is data with the special time stamp from the storage means, and reading the stamped data or the special time stamp from the data Reading means for outputting the removed non-stamped data as read data; and an acquisition output means for acquiring and outputting the read data output from the read means, wherein the read means includes the read stamped data. Outputting the read data at a timing that does not depend on the special time stamp, and reading And outputting the read data at a timing that depends on the special time stamp of each stamped data selectively performed.

  According to the present invention, it is properly controlled to record and output a plurality of continuous data.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a television apparatus to which a memory output device according to an embodiment of the present invention is applied.

  A television device (hereinafter referred to as “TV device”) 30 includes a digital tuner 1, an extraction unit (for example, a demultiplexer) 2, an analog tuner 6, a coding unit (for example, an MPEG encoder) 7, a first selector 8, and a special time stamp. The provision unit 9 and a storage medium (for example, hard disk or memory) 13 are provided. The TV device 30 includes a reading unit 12, a second selector 3, a buffer 85, a control unit (for example, a CPU (Central Processing Unit)) 71, a clock generator 10, a decoding unit (for example, an MPEG decoder) 4, a display control unit 5, A display screen 74, an IEEE 1394 interface circuit 91, and a third selector 75 are also provided.

  The digital tuner 1 receives MPEG2-TS (that is, a digital broadcast signal) from a digital broadcast source such as the digital broadcast unit 11A of the broadcast station 11 via the digital broadcast reception unit 51, and sends the MPEG2-TS to the extraction unit 2. Output.

  The extraction unit 2 extracts a plurality of transport packets of a channel designated via the user operation unit such as the remote controller 72 and the CPU 71 from the input MPEG2-TS, and extracts a plurality of extracted transport packets ( Hereinafter, this transport packet is referred to as “extracted packet”) to the first selector 8, the second selector 3, and / or the third selector 75.

  The analog tuner 6 receives an analog broadcast signal from an analog broadcast source such as the analog broadcast unit 11B of the broadcast station 11 via the analog broadcast reception unit 53 and outputs the signal to the encoding unit 7.

  The encoding unit 7 generates an MPEG2-TS based on the analog signal input from the analog tuner 6, and outputs each transport packet included in the TS to the first selector 8.

  The first selector 8 inputs the plurality of extracted packets output from the extraction unit 2 and the plurality of transport packets output from the encoding unit 7, and any one of the plurality of transports selected from them The packet (hereinafter, this transport packet is referred to as “first selection packet”) is output to the special time stamp assigning unit 9.

  The special time stamp assigning unit 9 attaches a special time stamp to each of the plurality of input first selection packets (for example, adds or embeds them), and a plurality of transport packets (hereinafter, referred to as the following) This transport packet is referred to as a “stamped packet”) and stored in the storage medium 13. As a result, one packet stream having a plurality of stamped packets including video data of a certain channel (in other words, a certain program) is converted into one data file or two or more divided data files. It is stored in the storage medium 13 as a fragment data file (hereinafter collectively referred to as “packet group file”). The “special time stamp” is time information related to the temporal position of the packet to which the stamp is attached. For example, the time when the first selection packet is input to the special time stamp assigning unit 9, or This is a time difference from a certain first selection packet (for example, the first selection packet immediately before or at the head) as a reference. This “special time stamp” is different from a time stamp included in advance in the transport packet, for example, PTS (Presentation Time Stamp) and DTS (Decoding Time Stamp) described later.

  The reading unit 12 sequentially reads a plurality of stamped packets included in the designated packet stream, and removes the special time stamp from the read stamped packet itself or the packet (hereinafter referred to as “ The read packet ”is output to the second selector 3 or the third selector 75. At that time, the reading unit 12 outputs the read packet at a timing that does not depend on the special time stamp included in the read stamped packet (that is, the timing when the special time stamp is ignored), and each of the read stamped The read data is selectively output at a timing depending on the special time stamp of the data (that is, a timing based on the special time stamp). This will be described in detail later.

  The second selector 3 inputs a plurality of extracted packets output from the extracting unit 2 and a plurality of read packets output from the reading unit 12, and any one of the plurality of transport packets ( Hereinafter, this transport packet is referred to as “second selection packet”) and stored in the buffer 85.

  The buffer 85 is a storage area provided in a volatile or non-volatile memory. The buffer 85 stores a plurality of second selection packets output from the second selector 3, and each of the stored plurality of second selection packets is read by the decoding unit 4 at an arbitrary timing.

  The control unit 71 controls the overall operation of the TV device 30, receives various command signals from the user via the user operation unit such as the remote controller 72, and executes various processes based on the command signals. To do. For example, the control unit 71 inputs a PCR (Program Clock Reference) output from the decoding unit 4, adjusts the frequency of the clock signal generated from the clock generator 10 based on the PCR, and outputs a signal from the digital broadcasting unit 11A. Match the frequency.

  The clock generator 10 is adjusted to synchronize with a predetermined frequency (for example, 27 MHz which is almost the same as the signal frequency of the digital broadcasting unit 11A but asynchronously) that oscillates without control, or is synchronized with the signal frequency of the digital broadcasting unit 11A by the control unit 71. A clock signal with the specified frequency is output. The output clock signal is input to the decoding unit 4, and the divided clock signal obtained by dividing the clock signal is used as a display timing control signal (typically a vertical synchronization signal) for display control. Input to part 5.

  The decoding unit 4 executes various processes at a timing synchronized with the input clock signal. For example, the decoding unit 4 uses the second selection packet (this embodiment) that is encoded data at the timing determined by the digital broadcasting unit 11A (that is, the timing according to the frequency of the clock signal synchronized with the digital broadcasting unit 11A). Then, the transport packet in MPEG2-TS) is read from the buffer 85, the second selection packet is decoded, the video data in the second selection packet is acquired, and the video data is sent to the display control unit 5. . At this time, since the data amount of the second selection packet is adjusted in advance by the digital broadcasting unit 11A, a failure such as overflow or underflow does not occur in the buffer 85. More specifically, when the extracted packet stream output from the extracting unit 2 is stored in the buffer 85 via the second selector 3 without being stored in the storage medium 13 (that is, when so-called real-time display is performed). Alternatively, when the extracted packet stream output at a timing depending on the special time stamp is stored in the buffer 85 (when special time stamp control is performed), the decoding unit 4 is based on the PCR from the digital broadcasting unit 11A. Since data is read from the buffer 85 in accordance with the adjusted clock signal frequency, there is no failure such as overflow or underflow.

  In addition, the decoding unit 4 controls the reading unit 12 by inputting a request signal to the reading unit 12, for example, at arbitrary timing (that is, timing according to the frequency of the clock signal oscillated without control), A plurality of read data obtained by reading from the storage medium 13 is output. For example, the decoding unit 4 acquires a plurality of read packets at an arbitrary timing by executing the flow control when the buffer 85 is empty (or when the accumulation amount of the second selection packet is small). In the flow control, the decoding unit 4 manages the buffer 85. For example, in the case of flow control, the decoding unit 4 has a larger storage amount of the second selection packet in the buffer 85 than a storage amount in the case of real-time display or special time stamp control (for example, 20% of the capacity of the buffer 85). The accumulated amount is maintained (for example, 80% of the capacity of the buffer 85). The data stored in the buffer 85 is erased by the decoding unit 4 or the control unit 71 when the flow control and real-time display or special time stamp control are switched, for example.

  The display control unit 5 displays the video data received from the decoding unit 4 on the display screen 74 at a timing based on the input divided clock signal (display timing control signal). The display screen 74 is a CRT, a liquid crystal display, a plasma display screen, or the like.

  The third selector 75 inputs a plurality of extracted packets output from the extracting unit 2 and a plurality of read packets output from the reading unit 12, and any one of the plurality of transport packets ( Hereinafter, this transport packet is referred to as a “third selection packet”) and is output to the IEEE 1394 interface circuit 91.

The D-VHS video deck 41 is connected to the IEEE 1394 interface circuit 91 via an IEEE 1394 (for example, i.Link (registered trademark)) cable 77. The IEEE 1394 interface circuit 91 receives the plurality of third selection packets output from the third selector 75, and outputs the plurality of third selection packets to the D-VHS video deck 41 via the IEEE 1394 cable 77. As a result, a plurality of third selection packets are transferred to the D-VHS (Digital-Video) in the D-VHS video deck 41 via the read / write control unit 42 mounted on the D-VHS video deck 41.
Home System) recorded on video tape 43. In addition to or in addition to the IEEE 1394 interface circuit 91, another communication interface circuit for transferring data to an external storage medium (for example, a magnetic tape medium such as the D-VHS video tape described above) based on another communication interface. May be provided.

  FIG. 2 is a configuration diagram of a transport stream in MPEG2.

  A TS 20 used in digital broadcasting includes a large number of transport packets 21 of a predetermined byte (for example, 188 bytes). Each transport packet 21 includes a transport header (hereinafter referred to as a TS header) 22 and a payload 23. That is, the TS 20 includes a series of transport packets corresponding to video signals such as digital video sources.

The TS 20 can multiplex and transmit a plurality of data including video and audio. In the TS header 22, a PID (Packet) for identifying the payload 23 of the transport packet 21 is included.
A field for storing (Identification) is provided. In reproducing a digital signal, first, extraction of desired data and reproduction of the extracted data are realized by combining payloads having the same PID among the PIDs stored in this field. Here, a PES (Packetized Elementary Stream) packet 25 is obtained by combining payloads having the same PID.

  Each PES packet 25 included in the PES packet stream 24 includes a PES header 26 and a PES data area 27. Note that the length of the PES packet 25 is arbitrary.

  By combining the PES data areas 27 in the respective PES packets 25, an elementary stream 28 directly related to the reproduced video / audio signal is formed. This elementary stream 28 is obtained by removing the PES header 26 from each PES packet 25 and combining the respective data areas 27. The elementary stream 28 is, for example, net data of video and audio data that has been highly efficient encoded by the MPEG2 system.

Although not shown in the drawing, the TS 20 has a program time reference reference value called PCR (Program Clock Reference) or a PTS (Presentation) so that video and audio are reproduced at a timing intended by the broadcasting source such as the broadcasting station 11. Time management information for reproduction called “Time Stamp” and time management information for decoding called “DTS (Decoding Time Stamp)” are added. The PCR is information for setting and calibrating the reference time on the broadcasting station 11 side, and is sent embedded in the TS 20. PTS and DTS are information indicating reproduction timing and decoding timing, respectively, and are embedded in the PES header 26 and transmitted.

  FIG. 3 shows a data structure in the TV apparatus 30.

  In the TV device 30, the TS input from the digital tuner 1 to the extraction unit 2 is as shown in FIG. 3A (and as shown in FIG. 2). That is, in the TS, for example, the transport packets 21 of the first channel and the transport packets 21 of the second channel are alternately arranged.

  In the extracting unit 2 to which this TS is input, when the transport packet 21 of the first channel is selected and output to the special time stamp assigning unit 9, the data structure is as shown in FIG. That is, when an extracted packet stream including a plurality of extracted packets is received, packets corresponding to the second channel packet removed without being extracted from the time when a certain first channel extracted packet (first extracted packet) is received. The next first channel extraction packet (second extraction packet) is received at an interval (in other words, an empty time length). For example, the “special time stamp” attached to the second extracted packet may be any information as long as the packet interval between the first extracted packet and the second extracted packet is obtained. For example, it may be the time when the special time stamp assigning unit 9 receives the second extracted packet, or the second extracted packet is received after receiving the first extracted packet (or a predetermined packet received before that). It may be a time difference until the special time stamp assigning unit 9 receives the time.

  Now, the data structure in the storage medium 13 when each extracted packet in the extracted packet stream shown in FIG. 3B is stored in the storage medium 13 with a special time stamp is shown in FIG. C). That is, when a plurality of stamped packets are stored in the storage medium 13, there is no physical interval between one stamped packet and the next stamped packet, and the reading unit 12 reads the stamped packet at the interval. In this case, it is possible to identify from the information indicated by the special time stamp attached to the stamped packet. In this embodiment, as can be seen from FIG. 3, a special time stamp 29 having a predetermined data length is added to the second selection packet (transport 21 in FIG. 3B). The data size is larger than the port packet itself. However, the special time stamp does not necessarily have to be added to the transport packet 21 and may be added in any way as long as it is associated with the transport packet 21 (for example, a predetermined time stamp in the transport packet 21 or A special time stamp may be embedded in any empty field).

  In this embodiment, the control unit 71 in the TV device 30 executes flow control on the decoding unit 4 when reproducing the packet group file (that is, a plurality of stamped packets) in the storage medium 13 on the display screen 74. In other words, the read unit 12 outputs a plurality of read packets at a timing that does not depend on the special time stamp of the read stamped packet. When the control unit 71 transfers the packet group file in the storage medium 13 to the D-VHS video deck 41 via the IEEE1394 interface circuit 91, the control unit 71 sends a special time stamp of the stamped packet read from the reading unit 12. A plurality of read packets are output at a timing depending on the. Hereinafter, this will be described in detail for (1) flow control and (2) data transfer to the D-VHS video tape 43.

  (1) Flow control.

  With reference to FIG. 1, the process flow performed in the case of flow control will be described.

  The CPU 71 receives a reproduction command desired by the user. The playback command includes a normal playback command for performing normal playback (in other words, 1 × speed play) and a trick play command. Here, “trick play” refers to playback other than normal playback. Specifically, for example, playback at N-times speed (N> 1 or N <1) or reverse playback (that is, fast forward, rewind, or slow). Reproduction etc.).

  The CPU 71 instructs the decoding unit 4 to execute the flow control when receiving either the normal reproduction instruction or the trick play instruction.

  In response to the flow control execution instruction from the CPU 71, the decoding unit 4 issues a request signal to the reading unit 12, and receives a plurality of stamped packets in the storage medium 13 at a timing based on the clock signal input from the clock generator 10. The reading unit 12 reads the data. Thereby, the reading unit 12 outputs the plurality of read data to the buffer 85 via the second selector 3 one after another at a timing that does not depend on the special time stamp included in the read stamped packet. In other words, the reading unit 12 ignores the special time stamp so that, for example, the output interval between the read first packet and the second packet is set to an empty interval as shown in FIG. 3B, for example. Without first, the first and second packets are output at a narrower interval (for example, substantially zero). The decoding unit 4 reads the second selection packets one after another from the buffer 85 at a timing based on the input clock signal, and the video data in the second selection packets are sequentially sent to the display control unit 5. As a result, the transmitted video data (for example, 30 images to be displayed per second) is displayed on the display screen 74 by the display control unit 5 based on the divided clock signal.

  The above is the processing flow when the flow control is executed. In addition, although it repeats, in this embodiment, the flow control mentioned above is performed also when not only a trick play command but a normal reproduction command is received from the user. Thereby, switching between trick play and normal reproduction is performed smoothly.

  (2) Data movement to the D-VHS video tape 43.

  In order for a video in a packet stream (hereinafter referred to as “tape recording packet stream”) recorded on a magnetic tape such as the D-VHS video tape 43 or the like to be properly reproduced, Individual packet intervals must be the same as individual packet intervals in the packet stream (packet stream having a plurality of extracted packets, hereinafter referred to as “extracted packet stream”) output from the extraction unit 2. is there.

  For this reason, when the control unit 71 receives a movement command to move (or copy) the packet stream in the storage medium 13 to the D-VHS video tape 43 from the user via the user operation unit, the control unit 71 Notify that there is a movement command.

  When receiving a notification that there is a movement command, the reading unit 12 reads a plurality of stamped packets in the packet stream stored in the storage medium 13, and at a timing depending on the special time stamp of each stamped data. Is output to the third selector 75. In other words, the reading unit 12 follows the information written in the special time stamp, for example, the output interval between the read first packet and the second packet as shown in FIG. 3B, for example. The first packet and the second packet are output at the packet interval. The reading unit 12 performs such processing for all the stamped packets included in the movement target packet stream in the storage medium 13, so that the broadcasted TS is not received and stored in the storage medium 13. A packet stream similar to the extracted packet stream for display in real time is output to the third selector 75. Thus, the packet stream is recorded on the D-VHS video tape 43 in the D-VHS video deck 41 from the third selector 75 via the IEEE 1394 interface circuit 91 and the IEEE 1394 cable 72.

  As described above, according to the above-described embodiment, a special time stamp is attached to each extracted packet in the extracted packet stream output from the extracting unit 2, and a packet stream having a plurality of stamped packets is stored in the storage medium 13. The When the packet stream is read and recorded on the magnetic tape, each of the plurality of packets in the packet stream is output to the magnetic tape at a timing depending on a special time stamp attached thereto. On the other hand, in the case of reproducing video data included in the packet stream in the storage medium 13, each of the plurality of packets in the packet stream does not depend on the special time stamp attached thereto under the control of the decoding unit 4. It is read to the decoding unit 4 at timing. Thereby, appropriate control based on the output mode is realized.

  By the way, the following modifications can be considered in the embodiment described above. Hereinafter, this will be described with reference to FIG.

  As shown in FIG. 4A, the decoding unit 4 displays a plurality of sub-screens each displaying a plurality of types of video data on the same display screen 74.

  Specifically, for example, when the control unit 71 receives a multi-screen display command from the user, the control unit 71 sends a multi-screen display notification to that effect to the decoding unit 4. In response to the notification, the decoding unit 4 displays a plurality of sub-screens each displaying a plurality of types of video data on the same display screen 74.

  For example, the decoding unit 4 displays the video data in the TS input to the digital tuner 1 on the first sub screen in real time without storing it in the storage medium 13. This real-time display is performed by the following processing flow, for example.

  The extraction unit 2 receives the TS output from the digital tuner 1, acquires a plurality of extracted packets from the TS, and outputs an extracted packet stream having the acquired plurality of extracted packets. The output extracted packet stream is input to the decoding unit 4 via the second selector 3 and the buffer 85. The decoding unit 4 sends the PCR in the input packet stream to the control unit 7.

  The control unit 7 adjusts the frequency output from the clock generator 10 based on the received PCR.

  The decoding unit 4 receives the frequency-adjusted clock signal from the clock generator 10 and outputs the video data in the input packet stream to the display control unit 5 based on the clock signal.

  Then, the decoding unit 4 performs the above-described flow control based on the same frequency-adjusted clock signal as that at the time of real-time display, whereby the video data contained in the packet stream in the storage device 13 is To be displayed on the screen.

  Thereafter, when the control unit 71 receives a single screen display command from the user, the control unit 71 sends a single screen display notification to that effect to the decoding unit 4. In response to the notification, the decoding unit 4 stops the above-described multi-screen display, and performs normal single-screen display without displaying a plurality of sub-screens on the display screen 74.

  At that time, in the TV device 30, when the real-time display is performed on a single screen (in other words, when the second sub-screen is deleted and the first sub-screen is left as a single screen), Even when a display based on flow control is performed on a single screen (in other words, when the first sub-screen is deleted and the second sub-screen is left as a single screen), the frequency of the clock signal is set to a plurality of frequencies. The frequency of the clock signal when the screen is displayed (that is, immediately before the display is switched) is maintained.

  That is, the control unit 71 does not change the frequency of the clock signal generated by the clock generator 10 even if a single screen display command is received when a plurality of screens are displayed. For this reason, as shown in FIG. 4B, the decoding unit 4 performs the above-described processing based on the flow control based on the clock signal at the time of multi-screen display (that is, immediately before display switching).

  As described above, according to this modified example, in the case of multi-screen display, reproduction based on flow control as well as real-time display is performed based on the clock signal after frequency adjustment at the time of real-time display. As a result, the plurality of sub-screens are displayed at a timing based on the same divided clock signal. As a result, the display timings of a plurality of types of video data displayed on a plurality of sub-screens can be synchronized, thereby preventing problems such as missing or repeated images (the same image is repeatedly displayed). it can.

  In addition, according to this modification, even when the display is switched from the multi-screen display to the single screen display and the display based on the flow control is performed in the single screen display, the clock signal immediately before the display switching (that is, at the time of real-time display) is used. Based on the flow control. As a result, it is possible to prevent the data accumulation amount in the buffer 85 from becoming discontinuous due to the change in the control method, so that switching from the multi-screen display to the single screen display can be performed smoothly.

  As mentioned above, although embodiment and the modification of this invention were demonstrated, these are the illustrations for description of this invention, Comprising: It is not the meaning which limits the scope of the present invention only to this embodiment and modification. The present invention can be implemented in various other forms.

  As one aspect of the present invention, the acquisition output means includes a reproduction control means for controlling reproduction of the read data, and a transfer means for transferring the read data to another storage means. When reproduction of a plurality of data stored in the storage means is performed, the read data is output to the reproduction control means at a timing independent of the special time stamp under the control of the reproduction control means, and the storage means When the process of transferring the data in the storage unit to the other storage unit is performed, the read data is transferred to the other storage unit via the transfer unit at a timing depending on the special time stamp of each stamped data. Also good. The other storage means is, for example, a magnetic tape medium capable of recording digital signals.

  As one aspect of the present invention, the acquisition output means is a reproduction control means for controlling reproduction of the read data, and the reproduction control means performs normal reproduction mode for reproduction at 1 × speed and reproduction other than 1 × speed reproduction. When executing any of the trick reproduction modes to be performed, the read means may be controlled so that the read data is output from the read means at a timing independent of the special time stamp.

  As one aspect of the present invention, the storage output device may further include clock generation means for generating a clock and clock frequency adjustment means for adjusting the frequency of the clock generated by the clock generation means. In this case, the acquisition output means is a reproduction control means for controlling reproduction of the read video data output from the reading means, and the acquisition means receives a plurality of first video data broadcasted by wire or wireless. And the clock frequency adjusting means adjusts the frequency of the clock based on reproduction timing adjustment information included in each of the plurality of first video data, and the clock generating means uses the frequency adjusted clock as the frequency adjusted clock. The reproduction control means prepares first and second sub-screens to be displayed on the display screen, and the plurality of first video data at the timing based on the frequency-adjusted clock. Display on the first sub-screen and acquire a plurality of the read second video data according to the frequency-adjusted clock, the same as the timing Said plurality of read second image data may be displayed on the second sub-screen timing. As a further aspect, when the plurality of video displays are switched to a single video display for displaying one type of video data on the display screen, and the second video data is displayed at that time, the playback is performed. The control means may acquire the read video data according to the frequency-adjusted clock before the switching, and display the plurality of read second video data on the display screen at a timing based on the frequency-adjusted clock.

  As one aspect of the present invention, each of the plurality of continuous data may be a transport packet included in a transport stream.

  The “continuous plural data” described above may be, for example, a series of connected data, or there may be regular or irregular intervals between data.

1 shows a television apparatus to which a memory output device according to an embodiment of the present invention is applied. The block diagram of the transport stream in MPEG2. The data structure in the TV apparatus 30 is shown. The figure for demonstrating the modification of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Digital tuner, 2 ... Demultiplexer, 3 ... 2nd selector, 4 ... MPEG decoder, 5 ... Display control part, 6 ... Analog tuner, 7 ... MPEG encoder, 8 ... 1st selector, 9 ... Special time stamp provision part DESCRIPTION OF SYMBOLS 10 ... Clock generator, 11 ... Broadcasting station, 12 ... Reading part, 13 ... Hard disk, 30 ... Television apparatus with a built-in hard disk, 41 ... D-VHS video deck, 42 ... Read-write control part, 43 ... D-VHS video Tape, 71 ... CPU, 72 ... Remote controller, 74 ... Display screen, 75 ... 3rd selector, 77 ... IEEE1394 cable

Claims (2)

Obtaining means for obtaining each of a plurality of continuous data;
A writing unit that adds a special time stamp representing information about a temporal position of the data to each of the plurality of acquired data and stores the data in a storage unit;
Each of the plurality of stamped data that is the data with the special time stamp is read from the storage means, and each of the read data with the stamp or the non-stamped data obtained by removing the special time stamp from the data is output as read data Reading means for
Acquisition output means for acquiring and outputting read data output from the reading means ;
Clock generating means for generating a clock;
Clock frequency adjusting means for adjusting the frequency of the clock generated by the clock generating means ,
The reading means outputs the read data at a timing independent of the special time stamp of each read stamped data, and reads the read at a timing dependent on the special time stamp of each read stamped data. Selectively outputting data ,
The acquisition output means is a reproduction control means for controlling reproduction of read video data output from the reading means,
The acquisition means receives a plurality of first video data broadcast by wire or wireless,
The clock frequency adjusting means adjusts the frequency of the clock based on reproduction timing adjustment information included in each of the plurality of first video data;
The clock generation means inputs the frequency adjusted clock to the reproduction control means,
The reproduction control means prepares first and second sub screens to be displayed on the display screen, and displays the plurality of first video data on the first sub screen at a timing based on the frequency-adjusted clock. And acquiring a plurality of read second video data according to the frequency-adjusted clock, and displaying the plurality of read second video data on a second sub-screen at the same timing as the timing.
Memory output device. When the multiple video display is switched to a single video display for displaying one type of video data on the display screen, and the second video data is displayed at that time,
The reproduction control means acquires the read video data according to the frequency-adjusted clock before switching, and displays the plurality of read second video data on the display screen at a timing based on the frequency-adjusted clock.
The memory output device according to claim 1 .

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