JP2009071470A - Signal processor, signal processing method and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly display the image of the program of a switching destination. <P>SOLUTION: A tuner control part 31 makes a tuner (background tuner) other than a tuner for viewing which selects the television signals of the channel of a viewing program time sequentially select and output all the television signals of the plurality of channels broadcast by a prescribed broadcasting system. The encoded data of the programs included in the television signals output from the background tuner are tentatively stored in a buffer part 18 for changeover for each program. When a program switching operation is performed, a buffer control part 32 makes the encoded data of the program of the switching destination be supplied from the buffer part 18 for the changeover to a decoding part 15, and a decoding control part 33 makes the decoding part 15 decode the encoded data of the program of the switching destination supplied from the buffer part 18 for the changeover to the decoding part 15. This invention is applicable to TV for instance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a signal processing device, a signal processing method, and a control program, and in particular, when a program switching operation for switching a program displayed on a display means such as a display to another program is performed, for example. The present invention relates to a signal processing device, a signal processing method, and a control program that allow an image of the program to be displayed quickly.

  For example, in digital broadcasting such as terrestrial digital broadcasting, program image data (image data constituting a program) is encoded into encoded data by a predictive encoding method such as MPEG (Moving Picture Experts Group) method, It is transmitted as a television signal in a predetermined frequency band (hereinafter referred to as a channel as appropriate).

  On the other hand, on the receiving side that receives a television broadcast, the tuner selects, for example, a television signal of a channel that includes program data instructed by the user from a broadcast signal that includes television signals of a plurality of channels. The encoded data as the program data included in the John signal is decoded by the predictive encoding method. Then, the image data of the program obtained as a result of the decoding is displayed on the display.

  One of the two tuners selects a television signal of a channel including program data to be viewed and recorded, and the other tuner selects a television signal of an electronic program guide providing channel. There has been proposed a recording / reproducing apparatus capable of reliably obtaining an electronic program guide even when a program is viewed and recorded by selection (see, for example, Patent Document 1).

Patent 3712204

  By the way, in the MPEG system representing the predictive coding system, a picture (frame or field) is divided into a picture to be intra-coded (hereinafter referred to as an intra picture as appropriate) and a picture to be inter-coded (hereinafter referred to as appropriate). Are encoded separately).

  Since non-intra pictures need to refer to other non-intra pictures or intra pictures for decoding, it is necessary to first decode intra pictures when decoding encoded data.

  Accordingly, when a user performs a program switching operation for switching a program whose image data is displayed on the display to another program on the receiving side that receives the television broadcast, the intra picture of the other program is encoded. Waiting for data to be transmitted, decoding from the intra picture is started.

  For this reason, it may take time until the image data of the switching destination program (other programs) is displayed after the program switching operation is performed.

  The present invention has been made in view of such a situation. When a program switching operation is performed, an image of a switching destination program is quickly displayed.

  A signal processing apparatus or control program according to one aspect of the present invention is a signal processing apparatus that processes a signal including television signals of a plurality of channels, or a control program that is executed by a computer that controls the signal processing apparatus. Two or more channel selection means for selecting and outputting a television signal of a predetermined channel from signals including television signals of a plurality of channels, and program data included in the television signal output by the channel selection means. Decoding means for decoding and outputting image data, display control means for displaying the image data output from the decoding means on the display means, and a television signal of a channel including the image data displayed on the display means are selected. Channel selection means other than the currently selected channel selection means As channel selection means, channel selection control means for causing the background channel selection means to select and output the television signals of the plurality of channels in a time division manner, and television signals output by the background channel selection means. When the program switching operation is performed in which the program data included is temporarily stored in the storage unit for each program and the program whose image data is displayed on the display unit is switched to another program. Storage control means for supplying the data from the storage means to the decoding means, and when the program switching operation is performed, the data of the other program supplied from the storage means to the decoding means, A signal processing device comprising a decoding control means for causing the decoding means to decode, or The serial computer, the channel selection control means, a storage control unit, and a control program to function as a decoding control unit.

  In the signal processing method of one aspect of the present invention, channel selection means other than the channel selection means for selecting a television signal of a channel including image data displayed on the display means is used as the background channel selection means. The background channel selection means causes the television signals of the plurality of channels to be selected and outputted in a time division manner, and the program data included in the television signal output by the background channel selection means is stored for each program. When the program switching operation for switching the program whose image data is displayed on the display means to another program is performed, the data of the other program is transferred from the storage means to the decoding means. From the storage means when the program switching operation is performed. The data of the other programs that are supplied to the serial decoder means, comprising the step of decoding to the decoding means.

  In one aspect of the present invention, channel selection means other than channel selection means for selecting a television signal of a channel including image data displayed on the display means is used as the background channel selection means, and the background channel is selected. The selecting means selects and outputs the television signals of the plurality of channels in a time division manner. Further, program data included in the television signal output from the background channel selection means is temporarily stored in the storage means for each program, and the program whose image data is displayed on the display means is switched to another program. When a program switching operation is performed, the data of the other program is supplied from the storage unit to the decoding unit, and the decoding unit stores the other program data supplied from the storage unit to the decoding unit. Decode the data.

  Note that the signal processing device may be an independent device or may be an internal block constituting one device.

  The control program can be provided by being transmitted through a transmission medium or by being recorded on a recording medium.

  According to one aspect of the present invention, when a program switching operation is performed, an image of a switching destination program can be quickly displayed.

  Embodiments of the present invention will be described below. Correspondences between the constituent elements of the present invention and the embodiments described in the specification or the drawings are exemplified as follows. This description is intended to confirm that the embodiments supporting the present invention are described in the specification or the drawings. Therefore, even if there is an embodiment that is described in the specification or the drawings but is not described here as an embodiment that corresponds to the constituent elements of the present invention, that is not the case. It does not mean that the form does not correspond to the constituent requirements. Conversely, even if an embodiment is described here as corresponding to a configuration requirement, that means that the embodiment does not correspond to a configuration requirement other than the configuration requirement. It's not something to do.

A signal processing apparatus or control program according to one aspect of the present invention includes:
A control program executed by a signal processing device (for example, the TV in FIG. 1) that processes signals including television signals of a plurality of channels, or a computer (for example, the control unit 20 in FIG. 1) that controls the signal processing device. Yes,
Two or more channel selection means (for example, tuners 11 ₁ to 11 _M in FIG. 1) for selecting and outputting a television signal of a predetermined channel from the signals including the television signals of the plurality of channels;
Decoding means for decoding program data included in the television signal output by the channel selection means and outputting image data (for example, the decoding unit 15 in FIG. 1);
Display control means (for example, the display control unit 16 in FIG. 1) for causing the display means (for example, the display panel 17 in FIG. 1) to display the image data output by the decoding means;
Channel selection means other than the channel selection means for selecting a television signal of a channel including image data displayed on the display means is used as a background channel selection means, and the background channel selection means includes the plurality of channels. Channel selection control means (for example, the tuner control unit 31 in FIG. 2) for selecting and outputting the television signal of time by time division;
The program data included in the television signal output from the background channel selection means is temporarily stored in the storage means (for example, the switching buffers 18 ₁ to 18 _N in FIG. 1) for each program, and the display means. Storage control means (for example, FIG. 2) for supplying data of the other program from the storage means to the decoding means when a program switching operation is performed to switch the program displaying the image data to another program. Buffer control unit 32) of
When the program switching operation is performed, a decoding control unit (for example, the decoding control unit 33 in FIG. 2) that causes the decoding unit to decode data of the other program supplied from the storage unit to the decoding unit. And a control program that causes the computer to function as the channel selection control means, storage control means, and decode control means.

A signal processing method according to one aspect of the present invention includes:
A signal processing method of a signal processing apparatus (for example, the TV in FIG. 1) that processes signals including television signals of a plurality of channels,
The signal processing device includes:
Two or more channel selection means (for example, tuners 11 ₁ to 11 _M in FIG. 1) for selecting and outputting a television signal of a predetermined channel from the signals including the television signals of the plurality of channels;
Decoding means for decoding program data included in the television signal output by the channel selection means and outputting image data (for example, the decoding unit 15 in FIG. 1);
Display control means (for example, the display control unit 16 in FIG. 1) for causing the display means to display the image data output by the decoding means;
Channel selection means other than the channel selection means for selecting a television signal of a channel including image data displayed on the display means is used as a background channel selection means, and the background channel selection means includes the plurality of channels. Are selected and output in a time division manner (for example, step S13 in FIG. 6),
The program data included in the television signal output from the background channel selection means is temporarily stored in the storage means for each program (for example, step S22 in FIG. 7), and the image data is displayed on the display means. When a program switching operation for switching a program to another program is performed, the data of the other program is supplied from the storage unit to the decoding unit (for example, step S24 in FIG. 7).
When the program switching operation is performed, the decoding unit decodes the data of the other program supplied from the storage unit to the decoding unit (for example, step S43 in FIG. 8).
Includes steps.

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

  FIG. 1 is a block diagram showing a configuration example of an embodiment of a TV (television receiver) as a signal processing apparatus to which the present invention is applied.

The tuner unit 11 includes a plurality of M tuners 11 ₁ , 11 ₂ ,..., 11 _M , which include predetermined broadcasts such as terrestrial digital broadcasts and BS (Broadcasting Satellite) digital broadcasts. A broadcast signal (RF (Radio Frequency) signal) of the system is supplied from an antenna (not shown).

The tuner 11 _m (m = 1, 2,..., M) selects a television signal of a predetermined channel from broadcast signals of a predetermined broadcast system supplied to the tuner unit 11 under the control of the control unit 20. (Extract) and output. The television signal of a predetermined channel output from the tuner 11 _m is supplied to the demodulator 12.

Here, selecting the television signal of a predetermined channel from the broadcast signal by the tuner 11 _m is hereinafter also referred to as receiving the television signal of the predetermined channel as appropriate.

Further, assuming that the total number of channels on which television signals are broadcast in a predetermined broadcasting system is the total number C of channels, the number _M of tuners 11 ₁ to 11 _{M included in} the tuner unit 11 is a number exceeding the total number of channels C + 1. There is no need to become.

The demodulation unit 12 demodulates the M channel television signals supplied from the tuners 11 ₁ to 11 _M of the tuner unit 11 and supplies the demodulated signals to the error correction unit 13.

  The error correction unit 13 performs error correction processing on the television signal of each channel from the demodulation unit 12, and supplies the transport stream as the M channel television signal obtained as a result to the demultiplexer unit 14.

  Under the control of the control unit 20, the demultiplexer unit 14 separates a TS (Transport Stream) packet including program image data and audio data from each M channel transport stream from the error correction unit 13, and the TS A packet image or audio elementary stream (ES) is constructed and output from the packet.

  Here, a single channel transport stream can include a plurality of programs (images and sounds thereof), but in the following, for simplicity of explanation, one channel transport stream includes one program stream. A program is included. In this case, when attention is paid to a certain time, the demultiplexer unit 14 can obtain elementary streams (images and sounds) of one program from each of the M channel transport streams. A mental stream is output.

  Of the audio elementary stream output from the demultiplexer unit 14, an audio elementary stream of a viewing program described later is supplied to an audio decoder (not shown) and decoded. The audio data obtained as a result of the decoding is supplied to a speaker (not shown), and the corresponding audio is output from the speaker.

  The elementary stream of the image output from the demultiplexer unit 14 is supplied to the decoding unit 15 and the switching buffer unit 18.

  That is, of the elementary streams of M program images to be output at a certain time, for example, the user selects one of the elementary streams that the user has selected to view by operating the operation unit 19. Elementary streams of images of programs (hereinafter referred to as viewing programs as appropriate) are supplied to the decoding unit 15.

  In addition, the elementary stream of M-1 program images other than the viewing program out of the M program image elementary streams output at a certain time by the demultiplexer unit 14 is the switching buffer unit 18. To be supplied.

  An elementary stream of an image is supplied to the decoding unit 15 from the demultiplexer unit 14 and the switching buffer unit 18.

  Under the control of the control unit 20, the decoding unit 15 decodes an elementary stream of an image supplied from the demultiplexer unit 14 or the switching buffer unit 18 by, for example, the MPEG system, and an image of a picture obtained as a result Data is supplied to the display control unit 16.

  That is, on the transmission side that transmits the television signal of each channel, the pictures constituting the program image are divided into an intra picture and a non-intra picture, and are encoded by the MPEG method. The elementary stream of the image includes encoded data obtained by the encoding, and the decoding unit 15 decodes the encoded data by the MPEG method.

  The encoded data includes, for example, 15 pictures and forms a group called GOP (Group Of Picture), and at least one intra picture is included in the 15 pictures constituting the GOP. Now, paying attention to the GOP, the decoding unit 15 starts decoding from the intra picture with the earliest display time among the 15 pictures constituting the GOP.

  The display control unit 16 performs display control for causing the display panel 17 to display an image corresponding to the image data from the decoding unit 15.

  That is, the display control unit 16 has a display buffer 16A, and sequentially writes one picture of image data supplied from the decoding unit 15 into the display buffer 16A in accordance with the control from the control unit 20, and displays the display buffer 16A. An image corresponding to the image data written in the buffer 16A is displayed on the display panel 17.

  The display panel 17 is composed of, for example, a liquid crystal panel or an organic EL (Electro Luminescence) panel, and displays an image corresponding to the image data stored in the display buffer 16A of the display control unit 16 according to the control of the display control unit 16. indicate.

The switching buffer unit 18 has a plurality of N switching buffers 18 ₁ , 18 ₂ ,..., 18 _N , and outputs M at a certain time according to the control of the control unit 20. Elementary streams of images of individual programs are temporarily stored for each program. In addition, the switching buffer unit 18 reads an elementary stream of an image of a certain program from the stored elementary streams of the image and supplies it to the decoding unit 15 under the control of the control unit 20.

That is, the switching buffer 18 _n (n = 1, 2,..., N) stores an elementary stream of an image of a certain program among elementary streams of an image of a program output from the demultiplexer unit 14. To do. In addition, the switching buffer 18 _n reads the stored elementary stream as necessary, and supplies it to the decoding unit 15.

Here, assuming that the maximum value of the number of programs that can be broadcast at the time of a predetermined broadcasting system is the maximum program number P, the number N of switching buffers 18 ₁ to 18 _{N included in} the switching buffer unit 18 is: For example, it is equal to the maximum program number P. In this case, the switching buffer unit 18 stores the elementary streams of all the images of the program broadcast at the time of a predetermined broadcasting system in such a manner that one switching buffer 18 _n is allocated to one program. Can do.

Further, the switching buffer 18 _n encodes an intra picture of another program pro ′ after that, for example, when a program switching operation for switching the viewing program from one program pro to another program pro ′ is performed. It has at least a storage capacity capable of storing encoded data corresponding to the maximum time required for a television signal including data to be transmitted and displayed.

That is, for example, as described above, it is assumed that the GOP is composed of 15 pictures, and that one of the 15 pictures is an intra picture and the other 14 pictures are non-intra pictures. In this case, if the picture cycle is, for example, 1/30 second, after a program switching operation is performed, a television signal including encoded data of an intra picture of another program pro 'is transmitted and displayed. Since the maximum time required for the display is 0.5 seconds (= 1/30 seconds × 15 pictures), the switching buffer 18 _n displays encoded data corresponding to 0.5 seconds in the display time for displaying pictures. Has at least a storage capacity capable of storing.

Here, in the present embodiment, the switching buffer 18 _n has a storage capacity capable of storing encoded data corresponding to, for example, about 0.5 seconds to 2.0 seconds in display time. And In this case, if encoded data corresponding to the storage capacity is stored in the switching buffer 18 _n , the encoded data includes encoded data of one or more intra pictures.

Note that the switching buffer 18 _n sequentially stores the encoded data (included in the elementary stream) supplied from the demultiplexer unit 14 and stores the encoded data corresponding to the storage capacity. Then, the switching buffer 18 _n is supplied from the demultiplexer unit 14. New encoded data is stored in the form of overwriting the oldest encoded data.

  The operation unit 19 is, for example, an operation panel provided on the housing of the TV in FIG. 1 or a remote commander for remotely controlling the TV. For example, when switching viewing programs or adjusting the volume, the operation unit 19 is described later. This is operated by the user when performing multi-display. Then, the operation unit 19 supplies an operation signal corresponding to the user operation to the control unit 20.

  The control unit 20 includes an EEPROM (Electrically and Erasable Programmable Read Only Memory) 21, a CPU (Central Processing Unit) 22, and a RAM (Random Access Memory) 23, and a tuner unit based on an operation signal from the operation unit 19. 11, each part of the TV such as the demultiplexer unit 14, the decoding unit 15, the display control unit 16, and the switching buffer unit 18 is controlled.

  That is, the EEPROM 21 stores programs executed by the CPU 22 and data necessary for the CPU 22 to perform processing.

  The CPU 22 controls each part of the TV by executing a program stored in the EEPROM 21.

  The RAM 23 temporarily stores data necessary for the operation of the CPU 23.

  The program executed by the CPU 22 is installed in the EEPROM 21 in advance, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto Optical) disk, a DVD (Digital Versatile Disc), a magnetic disk, It can be provided by being recorded on a removable recording medium such as a semiconductor memory and installed in the EEPROM 21.

  The program can be downloaded via a network such as digital broadcasting or the Internet and installed in the EEPROM 21.

Here, in order to simplify the description, the number M of the tuners 11 ₁ to 11 _M included in the tuner unit 11 is, for example, two, and the switching buffer 18 _{1 included in the} switching buffer unit 18. 1 to 18 _N is assumed to be six, for example, and the TV in FIG. 1 will be described.

That is, FIG. 2 shows a configuration example of the TV of FIG. 1 having _two tuners 11 ₁ and 11 ₂ and six switching buffers 18 ₁ to 18 ₆ .

  In FIG. 2, the demodulation unit 12, the error correction unit 13, and the demultiplexer unit 14 of FIG. 1 are not shown. The control unit 20 functions as a tuner control unit 31, a buffer control unit 32, a decode control unit 33, and a multi-display control unit 34 when the CPU 22 in FIG.

Here, _{one of} the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 that selects (continues to select) the television signal of the channel including the image (data) displayed on the display panel 17. Is hereinafter referred to as a viewing tuner as appropriate. Further, of the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11, a tuner other than the viewing tuner is hereinafter appropriately referred to as a background tuner.

In FIG. 2, the tuner unit 11 is composed of two tuners 11 ₁ and 11 ₂ , so one of the two tuners 11 ₁ and 11 ₂ is a viewing tuner, and the other is Become a background tuner.

In the TV, the encoded data (elementary stream) of the program included in the television signal output from the viewing tuner of the _two tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 is received by the demodulation unit 12 and the error. The data is supplied to the decoding unit 15 via the correction unit 13 and the demultiplexer unit 14 (FIG. 1). Also, the encoded data of the program included in the television signal output from the background tuner of the _two tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 is converted into the demodulator 12, the error correction unit 13, and the decoder. The signal is supplied to the switching buffer unit 18 via the multiplexer unit 14.

  In other words, the tuner control unit 31 controls the tuner unit 11, so that the viewing tuner is set to the channel of the viewing program among the television signals of a plurality of channels included in the broadcast signal supplied to the tuner unit 11. Select and output a television signal.

  Further, the tuner control unit 31 controls the tuner unit 11 to cause the background tuner to select and output the television signals of all the channels included in the broadcast signal supplied to the tuner unit 11 in a time division manner. Let

For example, immediately after the power of the TV is turned on, one of the two tuners 11 ₁ and 11 ₂ constituting the tuner unit 11, for example, the tuner 11 ₁ becomes a viewing tuner, and the viewing is performed. A program in which the encoded data is included in the television signal output from the tuner 11 _1, which is a general tuner, is a viewing program.

Here, for example, as described above, the number N of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18 is the maximum number of programs that can be broadcast at a time that is a predetermined broadcasting system (programs). 2, since the number N of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18 is 6, the maximum program number P is 6.

  For example, as described above, if one transport stream includes one program, the number of channels included in the broadcast signal supplied to the tuner unit 11 is equal to the maximum program number P. There are 6 equal channels.

  In this case, the background tuner selects (receives) and outputs the television signals of all six channels in a time division manner.

That is, as shown in FIG. 2, the tuner unit 11 is composed of two tuners 11 ₁ and 11 ₂ , and one of them is a viewing tuner, so that there is only one background tuner. The one background tuner receives television signals of all six channels in a time division manner.

  For example, when the tuner unit 11 is composed of three tuners, two of them are background tuners, and therefore, six channels are assigned to the two background tuners as evenly as possible. That is, three of the six channels are assigned to one of the two background tuners, and the remaining three channels are assigned to the other. Each background tuner receives a television signal of a channel assigned to the background tuner in a time division manner.

  Therefore, when the tuner unit 11 has a number of tuners obtained by adding 1 to the number of channels included in the broadcast signal supplied to the tuner unit 11 (total number of channels C), each tuner serving as a background tuner has 1 Each channel is assigned, and as a result, the background tuner continues to receive the one-channel television signal assigned to the background tuner.

  The buffer control unit 32 temporarily stores the encoded data of the program included in the television signal output from the background tuner of the tuner unit 11 in the switching buffer unit 18 for each program.

  That is, in FIG. 2, as described above, the broadcast signal includes 6-channel television signals, and the 1-channel television signal includes encoded data of one program. The background tuner of the tuner unit 11 receives and outputs 6-channel television signals in a time-division manner, so that encoded data of six programs is supplied to the switching buffer unit 18 in a time-division manner. The

As described above, the buffer control unit 32 provides six programs that are supplied from the tuner unit 11 (via the demodulation unit 12, the error correction unit 13, and the demultiplexer unit 14) to the switching buffer unit 18 in a time division manner. Are stored in each of the _six switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18.

That is, the buffer control unit 32 assigns one of the six programs to which the encoded data is supplied from the tuner unit 11 in a time division manner to each switching buffer 18 _n constituting the switching buffer unit 18. the switching buffer 18 _n, and stores the program of the encoded data assigned to the switching buffer 18 _n.

  Therefore, the switching buffer unit 18 temporarily stores encoded data of all six programs broadcast in a predetermined broadcasting system.

  In addition, when the user performs a program switching operation and a program switching signal corresponding to the operation is supplied from the operation unit 19 to the control unit 20, the buffer control unit 32 performs a program switching operation. The encoded data of the designated switching destination program is supplied from the switching buffer unit 18 to the decoding unit 15.

That is, as described above, the switching buffer unit 18 temporarily stores encoded data of all six programs broadcast in a predetermined broadcasting system. The buffer control unit 32 causes the encoded data of the program to be supplied to the decoding unit 15 from the switching buffer 18 _n storing the encoded data of the switching destination program designated by the program switching operation.

  The decode control unit 33 is supplied from the tuner unit 11 (via the demodulation unit 12, the error correction unit 13, and the demultiplexer unit 14) to the decode unit 15 unless an operation signal is supplied from the operation unit 19 to the control unit 20. The decoding unit 15 is controlled so as to decode the encoded data of the program (viewing program) included in the television signal of the channel of the viewing program, that is, the television signal of the channel received and output by the viewing tuner. Yes.

  When the user performs a program switching operation and a program switching signal as an operation signal corresponding to the operation is supplied from the operation unit 19 to the control unit 20, the decoding control unit 33 switches the switching buffer unit 18. The decoding unit 15 is controlled so as to decode the encoded data of the program supplied to the decoding unit 15.

That is, when a program switching operation is performed, as described above, the decoding unit 15 stores the encoded data of the switching destination program designated by the program switching operation from the switching buffer 18 _n. , encoded data of that program, because it is supplied to the decoding unit 15, to decode the program of the encoded data from the switching buffer 18 _n, the decoding control unit 33 controls the decoding section 15.

The multi-display control unit 34 displays a program image in which encoded data is stored in the _six switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18 on the display panel 17 in a multi-screen. That is, for example, when the user operates the operation unit 19 so as to display a multi-screen (multi-display), and an operation signal corresponding to the operation is supplied from the operation unit 19 to the control unit 20, The display control unit 16 and the like are controlled to display a multi-screen. Note that the display control unit 16 causes the display panel 17 to display an image on a multi-screen under the control of the multi-display control unit 34.

Next, operations of the two tuners 11 ₁ and 11 ₂ and the six switching buffers 18 ₁ to 18 ₆ in FIG. 2 will be described with reference to FIG.

  In FIG. 3, the horizontal direction represents time.

  Of the 6-channel television signals included in the broadcast signal, the i-th channel (i-th channel) is referred to as a channel ch # i television signal and a program included in the channel ch # i television signal. The encoded data is referred to as encoded data of the program pro # i.

  Furthermore, for example, an image of the program pro # 1, for example, among the six programs pro # 1 to pro # 6 in which the encoded data is included in the television signals of the six channels ch # 1 to ch # 6, respectively. Are displayed on the display panel 17, and therefore the program pro # 1 is a viewing program.

Further, one of the two tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 of FIG. 2, for example, the tuner 11 ₁ is a viewing tuner, and the other tuner 11 ₂ is Suppose you are a background tuner.

In this case, the tuner 11 _{1 serving} as the viewing tuner, as shown in FIG. 3, follows the channel ch # 1 of the program pro # 1 serving as the viewing program from the broadcast signal according to the control of the tuner control unit 31. The television signal is received and supplied to the decoding unit 15. The decoding unit 15 decodes the encoded data of the program pro # 1 included in the television signal of the channel ch # ₁ from the tuner 11 _{1 serving as} the viewing tuner, and performs display control on the image data obtained as a result. Supply to unit 16. The display control unit 16 (FIG. 2) writes the image data from the decoding unit 15 to the display buffer 16A, whereby the image of the program pro # 1 is displayed on the display panel 17.

On the other hand, the tuner 11 ₂ which is the background tuner under the control of the tuner controller 31, as shown in FIG. 3, the 6-channel ch # 1 to the television signal of the ch # 6 included in a broadcast signal, when The divided data are received and supplied to the switching buffer unit 18.

That is, the tuner control unit 31 sets a period (hereinafter referred to as a slot period) T for receiving (selecting) a one-channel television signal, and for each slot period T, 6 channels ch # 1 to ch # each of the six television signal, is received by the time division tuner 11 ₂ two that is the background tuner.

As a result, the tuner 11 _{2 serving as the} background tuner, for example, the first channel ch of the six-channel ch # 1 to ch # 6 television signals from a certain time t ₀ to the slot period T, for example. The # 1 television signal is received and supplied to the switching buffer unit 18.

Further, the tuner 11 ₂ which is the background tuner, from time t ₀ + T from the time t ₀ has elapsed slot period T is, during the slot period T, the channel ch # 1 of the following 2-th channel ch # 2 television signals are received and supplied to the switching buffer unit 18.

Further, the tuner 11 ₂ which is the background tuner, from time t ₀ + 2T slot period T has elapsed from the time t ₀ + T, during slot period T, the channel ch # 2 of the following 3-th channel The ch # 3 television signal is received and supplied to the switching buffer unit 18.

Then, the tuner 11 ₂ which is the background tuner, similarly, each during slot period T, sequentially receives the channel ch # 4, ch # 5, the television signal of the ch # 6, then again, Repeated time-division reception from the television signal of the first channel ch # 1.

  The slot period T is set to a value capable of receiving a television signal including encoded data for about 0.5 seconds or more (about 2 seconds or less) in display time. As described above, when 1 GOP is composed of 15 pictures, the encoded data included in the television signal received during the slot period T includes encoded data of one or more intra pictures. .

On the other hand, the switching buffer unit 18, as described above, the encoded data included in the television signal received by the time the tuner 11 ₂ which is the background tuner division, under the control of the buffer control unit 32, a program Every time it is temporarily stored.

That is, the buffer control unit 32 assigns, for example, a program pro # i to the switching buffer 18 _i constituting the switching buffer unit 18 and, as shown in FIG. 3, the background tuner (in this case, the tuner 11 _2). ), The encoded data of the program pro # i included in the television signal of the channel ch # i received during the slot period T is stored.

Unless the program switching operation is performed, the tuner 11 _{1 serving} as the viewing tuner receives the television signal of the channel ch # 1 of the program pro # 1 serving as the viewing program from the broadcast signal, and the decoding unit 15 To supply. Further, the tuner 11 ₂ which is the background tuner, a 6 channel ch # 1 to the television signal of the ch # 6 included in the broadcast signal, received by time division, and supplies the switching buffer unit 18. In the switching buffer unit 18, the tuner 11 _{2 serving as the} background tuner in the switching buffers 18 ₁ to 18 ₆ is included in the television signals of the channels ch # 1 to ch # 6 received in time division. The encoded data of programs pro # 1 to pro # 6 are stored respectively.

Next, FIG. 4 shows the stored contents of the switching buffers 18 ₁ to 18 ₆ of the switching buffer unit 18.

For example, as described in FIG. 3, and the tuner 11 ₂ becomes the background tuner, the switching buffer 18 _i, if assigned a program pro # i, in to the buffer 18 ₁ for switching 18 _6, program pro # 1 through pro # 6 of the coded data to no channel ch # 1 received by the time the tuner 11 ₂ division has become the background tuner included in the television signal ch # 6 are respectively stored.

  In FIG. 4, I represents intra-picture encoded data (encoded data obtained by intra-coding image data), and NI represents non-intra-coded encoded data (image data inter-coded). (Encoded data obtained by converting the data).

As described in FIG. 3, the slot period T tuner 11 ₂ receives a television signal of one channel that is the background tuner, encoded data of minute or about 0.5 seconds in display (or 1GOP min) Is set to a value capable of receiving a television signal including. Thus, since the encoded data included in the television signal received during the slot period T includes encoded data of one or more intra pictures I, the encoded data stored in the switching buffer 18 _i is encoded. The data also includes one or more intra-picture I encoded data.

Next, referring to FIG. 5, the operations of the two tuners 11 ₁ and 11 ₂ and the six switching buffers 18 ₁ to 18 ₆ in FIG. 2 when a program switching operation is performed. explain.

  In FIG. 5 as well, the horizontal direction represents time as in FIG.

Now, as in the case of FIG. 3, one of the two tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 of FIG. 2, for example, the tuner 11 ₁ is a viewing tuner, tuner 11 ₂ which is the other, and has a background tuner.

In this case, as described with reference to FIG. 3, the tuner 11 _{1 serving} as the viewing tuner receives the television signal of the channel ch # 1 of the program pro # 1 serving as the viewing program from the broadcast signal, This is supplied to the decoding unit 15.

The decoding unit 15 decodes the encoded data of the program pro # 1 included in the television signal from the tuner 11 _{1 serving as} the viewing tuner, and the image data of the program pro # 1 obtained as a result of the decoding is This is supplied to the display control unit 16. The display control unit 16 writes the image data of the program pro # 1 from the decoding unit 15 to the display buffer 16A, whereby the image of the program pro # 1 is displayed on the display panel 17.

Further, the tuner 11 ₂ which is the background tuner, a 6 channel ch # 1 to the television signal of the ch # 6 included in the broadcast signal, received by time division, and supplies the switching buffer unit 18. In the switching buffer unit 18, the tuner 11 _{2 serving as the} background tuner in the switching buffers 18 ₁ to 18 ₆ is included in the television signals of the channels ch # 1 to ch # 6 received in time division. The encoded data of programs pro # 1 to pro # 6 are stored respectively.

Now, for example, the tuner 11 ₂ which is the background tuner, in the slot period T, for receiving a television signal of the channel ch # 5, the program pro # 5 of channel ch # 5 is allocated switched the buffer 18 _5, in the channel ch # halfway encoded data of the program pro # 5 contained 5 of the television signal is stored time t _1, a viewed program from the program pro # 1, other program For example, it is assumed that a program switching operation for switching to the program pro # 4 is performed.

  In this case, the buffer control unit 32 controls the switching buffer unit 18 and supplies the encoded data of the switching destination program pro # 4 designated by the program switching operation from the switching buffer unit 18 to the decoding unit 15. Let

That is, in this case, the program pro # 4 encoded data, since the program pro # 4 is stored in the switching buffer 18 ₄ allocated, the program pro stored in the switching buffer 18 ₄ The encoded data of # 4 is supplied from the switching buffer unit 18 to the decoding unit 15.

Here, as described with reference to FIG. 4, each of the switching buffers 18 ₁ to 18 ₆ stores encoded data of one or more intra pictures. The buffer control unit 32 monitors (manages) the position where the encoded data of the intra picture is stored for each of the switching buffers 18 ₁ to 18 ₆ , and the code from the switching buffer 18 _i to the decoding unit 15 is monitored. The supply of encoded data is started from encoded data of an intra picture (for example, when encoded data of a plurality of intra pictures is stored, for example, encoded data of an intra picture having the latest display time). The switching buffer unit 18 is controlled.

By starting the supply of the encoded data from the switching buffer 18 _i to the decoding unit 15 from the encoded data of the intra picture, the decoding unit 15 can immediately start decoding the encoded data. .

  On the other hand, when a program switching operation is performed, the decoding control unit 33 controls the decoding unit 15 to decode the encoded data of the program supplied from the switching buffer unit 18 to the decoding unit 15.

Thus, the decoding unit 15 replaces the encoded data of the program pro # 1 included in the television signal from the tuner 11 _{1 serving as} the viewing tuner with the program pro # supplied from the switching buffer unit 18. The decoding of the encoded data of 4 is started, and the image data of the program pro # 4 obtained as a result of the decoding is supplied to the display control unit 16. The display control unit 16 writes the image data of the program pro # 4 from the decoding unit 15 to the display buffer 16A, whereby the display panel 17 replaces the image of the program pro # 1 with the program pro # 4. An image is displayed.

As described above, the tuner 11 ₂ which is the background tuner, 6-channel ch # 1 no predetermined broadcast system by receiving a time division all television signals ch # 6 is output, the 6-channel ch The switching buffer 18 for the programs included in the television signals # 1 to ch # 6, that is, the encoded data of all the programs pro # 1 to pro # 6 broadcast in a predetermined broadcasting system, for each program. while to be stored in the viewing program, the program pro # 1, when the operation of the program is switched to switch the program pro # 4 is another program is performed, program the switching buffer 18 ₄ already stored pro Since the encoded data of # 4 is supplied from the switching buffer unit 18 to the decoding unit 15 and decoded, the program switching operation is performed, and then the intra picture of the switching destination program pro # 4 is performed. Without waiting for that No. of data transmitted, it is possible to start the display of the program pro # 4 images. Therefore, when the program switching operation is performed, the image of the switching destination program can be quickly displayed.

As described above, the viewing program, the program pro # 1 operation of the program is switched to switch the program pro # 4 from is performed, is stored in the switching buffer 18 _4, switching destination program pro # 4 encoded data , supply to the decoding unit 15, and when the decoding is started, the tuner control unit 31, the tuner 11 ₂ is the background tuner which has been received in a time division television signal switching destination program pro # 4 , together with the new viewing tuner, the tuner 11 ₁ is other tuner as a background tuner, as shown in FIG. 5, the tuner 11 ₂ a view tuner, the switching destination program pro # 4 television together to receive the television signal, the tuner 11 ₁ is the background tuner, receives in time division 6 channels of television signals included in the broadcast signal To.

Here, assuming that the frequency increases in the direction from channel ch # 1 to ch # 6, in FIG. 5, in tuner 11 ₁ which is the background tuner, channel ch # of program pro # 4 to be switched to. Reception in time division is started from the television signal of channel ch # 5 adjacent to the higher frequency of No. 4.

As described above, the tuner 11 ₂ a view tuner, after starting the reception and output of the switching destination program pro # 4 of the television signal, the program pro # 4 stored in the switching buffer 18 ₄ code encoded data subsequent to the data, or, when receiving and outputting encoded data of the intra-picture of the program pro # 4, the decoding control unit 33, the program pro # 4 outputted by the tuner 11 ₂ a view tuner The decoding unit 15 is controlled to decode the encoded data.

When the tuner 11 _1, which is a background tuner, starts receiving and outputting the 6-channel television signal included in the broadcast signal in a time-sharing manner, the buffer control unit 32 switches the switching that constitutes the switching buffer unit 18. The programs are reassigned to the buffers 18 ₁ to 18 ₆ , and the encoded data included in the 6-channel television signal output by the tuner 11 _{1 as the} background tuner in a time division manner is assigned. The encoded data of the recorded program is stored.

In FIG. 5, after the operation of the program switching is, the program pro # 5 to the switching buffer 18 _6, the program pro # 6 to the switching buffer 18 _1, the program pro # to the switching buffer 18 ₂ 1, the program pro # 2 to the switching buffer 18 _3, the program pro # 3 to the switching buffer 18 _4, the program pro # 4 to the switching buffer 18 ₅ are assigned respectively.

  Next, the control process (tuner control process) of the tuner unit 11 by the tuner control unit 31 of FIG. 2 will be further described with reference to the flowchart of FIG.

For example, when the power source of the TV in FIG. 2 is turned on from off, the tuner control unit 31 controls the tuner unit 11 in step S11, so that the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 are controlled. For example, the tuner 11 ₁ is a viewing tuner, and the tuner 11 ₁ , which is the viewing tuner, receives the television signal of the channel received by the viewing tuner immediately before the last power-off. And the process proceeds to step S12.

Tuner 11 ₁ is a view tuner under the control of the tuner controller 31, receives a television signal of a predetermined channel (selection) of. Program encoded data tuner 11 ₁ is a view for tuner included in the television signal of a predetermined channel received via the (demodulation unit 12, error correction unit 13 and the demultiplexer 14, (FIG. 1)) And supplied to the decoding unit 15.

Decoding unit 15 decodes a program coded data included in the channel of the television signal from the tuner 11 ₁ has a viewing tuner, an image data obtained as a result thereof to the display control unit 16. The display control unit 16, the image data from the decoding unit 15, the writing in the display buffer 16A, thereby, the display panel 17, a program of the image tuner 11 ₁ is included in the television signal of the channel being received Is displayed.

In step S12, the tuner control unit 31 controls the tuner unit 11 so that all of the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 other than the viewing tuner, that is, the tuner 11 ₂ is backed up. as a ground tuner, the tuner 11 ₂ which is a background tuner assigns a channel to be received in a time division television signal.

Here, in this case, the number of channels of the predetermined broadcasting system is 6 channels as described above, and since the background tuner is only one tuner 11 ₂ , the one tuner 11 _{On the} other hand, all six channels are assigned as channels on which the background tuner should receive television signals in a time-division manner (hereinafter referred to as background reception target channels as appropriate).

Further, in step S12, the tuner control unit 31, the tuner 11 ₂ is the background tuner sets the slot period T for receiving each channel of the background to be received, the process proceeds to step S13.

In step S13, the tuner control unit 31, respectively 6 channels assigned as the channel of the background to be received, to receive a time-division for each slot period T, by controlling the tuner 11 ₂ is the background tuner The process proceeds to step S14.

Thus, the tuner 11 ₂ is the background tuner starts to six channels, respectively television signals assigned as a channel background reception object, and outputs the received in time division for each slot period T. Program coded data tuner 11 ₂ is the background tuner is included in 6 channels each television signal to be output is temporarily stored is supplied to the switching buffer unit 18.

  In step S14, when the tuner control unit 31 determines whether the user has performed a program switching operation and determines that the program switching operation has not been performed, the process returns to step S14.

When it is determined in step S14 that the user has performed a program switching operation, the process proceeds to step S15, and the tuner control unit 31 controls the tuner unit 11 to thereby adjust the tuners constituting the tuner unit 11. Of 11 ₁ and 11 _2, the one to which the channel of the switching destination program is assigned as the channel of the background reception target is set as the new viewing tuner, and the switching destination program is set as the new viewing tuner. The television signal of the channel containing the encoded data of is received.

  Thereafter, the process returns from step S15 to step S12, and as described above, a tuner other than the viewing tuner is set as a new background tuner, and a channel to be received by the background is set for the new background tuner. Thereafter, the same processing is repeated.

  Here, the tuner control processing by the tuner control unit 31 of FIG. 6 ends when the power of the TV is turned off, for example.

  Next, the control process (buffer control process) of the switching buffer unit 18 by the buffer control unit 32 of FIG. 2 will be further described with reference to the flowchart of FIG.

For example, when the power source of the TV in FIG. 2 is switched from OFF to ON, the buffer control unit 32 sets the tuner unit 11 to each of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18 in step S21. Any one of six programs to which encoded data is supplied in a time division manner from the background tuner is assigned as a program to be temporarily stored (hereinafter referred to as a temporary storage program as appropriate). Proceed to S22.

In step S22, the buffer control unit 32 controls the switching buffer unit 18 so that each of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18 receives a signal from the background tuner of the tuner unit 11 ( The encoded data of the program allocated as the temporary storage program among the encoded data of the 6 programs included in the supplied 6-channel television signal (by time division) is stored, and the process proceeds to step S23.

That is, as a result, in each of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18, six programs included in the six-channel television signal supplied from the background tuner by the tuner control processing of FIG. Of the encoded data, the encoded data of the program assigned as the temporarily stored program is stored.

  In step S23, if the buffer control unit 32 determines whether the user has performed a program switching operation and determines that the user has not performed a program switching operation, the process returns to step S23.

  If it is determined in step S23 that the user has performed a program switching operation, the process proceeds to step S24, and the buffer control unit 32 controls the switching buffer unit 18 to perform the program switching operation. The encoded data of the designated switching destination program is supplied from the switching buffer unit 18 to the decoding unit 15.

That is, as described above, the switching buffer unit 18 temporarily stores encoded data of all six programs broadcast in a predetermined broadcasting system. The buffer control unit 32 causes the decoding unit 15 to supply the encoded data of the switching destination program from the switching buffer 18 _n storing the encoded data of the switching destination program designated by the program switching operation. .

The supply of the encoded data of the switching destination program from the switching buffer 18 _n storing the encoded data of the switching destination program designated by the program switching operation to the decoding unit 15 is shown in FIG. As described above, it starts from encoded data of an intra picture.

Thereafter, the process returns from step S24 to step S21, and the buffer control unit 32 receives the encoded data from the background tuner of the tuner unit 11 in each of the switching buffers 18 ₁ to 18 ₆ constituting the switching buffer unit 18. Any one of the six programs supplied in time division is newly allocated as a temporarily stored program, and the same processing is repeated thereafter.

That is, when a program switching operation is performed, in the tuner control process of FIG. 6, as described above, a background reception target channel is assigned to a new background tuner, and as a result, a switching buffer unit In 18, encoded data of six programs are supplied from a new background tuner in a time-sharing manner. Therefore, in step S21 in which the process returns from step S24, the encoded data is transmitted from the background tuner. Any one of the six programs supplied in a divided manner is newly assigned to each of the switching buffers 18 ₁ to 18 ₆ as a temporary storage program.

  Here, the buffer control processing by the buffer control unit 32 in FIG. 7 ends when the power of the TV is turned off, for example.

  Next, the control process (decode control process) of the decode unit 15 by the decode control unit 33 of FIG. 2 will be further described with reference to the flowchart of FIG.

For example, when the power of the TV in FIG. 2 is turned on from off, the decode control unit 33 receives and outputs the viewing tuner of the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 in step S41. The decoding unit 15 is controlled so that the encoded data of the program (viewed program) included in the television signal of the channel to be decoded is to be decoded (decoding target), and the process proceeds to step S42.

Thereby, the decoding unit 15 decodes the encoded data of the viewing program included in the television signal of the channel from the viewing tuner of the tuners 11 ₁ and 11 ₂ , and displays the image data obtained as a result of the display control. Supply to unit 16. The display control unit 16 writes the image data from the decoding unit 15 into the display buffer 16 </ b> A, whereby the image of the viewing program is displayed on the display panel 17.

  In step S42, when the decode control unit 33 determines whether or not the user has performed a program switching operation and determines that the program switching operation has not been performed, the process returns to step S42.

  If it is determined in step S42 that the user has performed a program switching operation, the process proceeds to step S43, and the buffer control unit 32 encodes the encoded data supplied from the switching buffer unit 18, that is, the program. The decoding unit 15 is controlled so that the encoded data of the switching destination program designated by the switching operation is the decoding target (decoding target).

  Thus, the decoding unit 15 decodes the encoded data of the switching destination program supplied from the switching buffer unit 18 and supplies the image data obtained as a result to the display control unit 16. The display control unit 16 writes the image data from the decoding unit 15 into the display buffer 16 </ b> A, whereby the image of the program to be switched to is displayed on the display panel 17.

  That is, when a program switching operation is performed, in the buffer control process of FIG. 7, as described above, the encoded data of the switching destination program designated by the program switching operation is transferred from the switching buffer unit 18 to the decoding unit. 15 is supplied.

  In step S43, the decoding unit 15 is controlled so as to decode the encoded data of the switching destination program supplied from the switching buffer unit 18 to the decoding unit 15.

Thereafter, the process returns from step S43 to step S41, and the decode control unit 33 receives the television of the channel received and output by the new viewing tuner among the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11. The decoding unit 15 is controlled so that the encoded data of the program (viewing program) included in the signal is to be decoded, and thereafter the same processing is repeated.

That is, when the program switching operation is performed, in the tuner control processing of FIG. 6, as described above, the channel of the switching destination program among the tuners 11 ₁ and 11 ₂ constituting the tuner unit 11 is changed to the background. The channel assigned as the reception target channel is used as a new viewing tuner, and the new viewing tuner receives and outputs a television signal of a channel including encoded data of the program to be switched to.

  The decoding control unit 33 stores the new data for viewing while decoding the encoded data of the switching destination program stored in the switching buffer unit 18 and supplied from the switching buffer unit 18 to the decoding unit 15. The switching destination program received by the tuner and supplied to the decoding unit 15 is supplied from the switching buffer unit 18 to the decoding unit 15 in the encoded data of the last picture (of the switching destination program). The decoding unit 15 is controlled to start decoding from the encoded data.

  Here, the new viewing tuner fails to receive the encoded data of the picture following the encoded data of the last picture supplied from the switching buffer unit 18 to the decoding unit 15 of the switching destination program. If so, the decoding control unit 33 causes the decoding unit 15 to start decoding from the encoded data of the intra-picture of the switching destination program received by the new viewing tuner and supplied to the decoding unit 15. Control.

  Further, the decoding control process by the decoding control unit 33 in FIG. 8 ends when the power of the TV is turned off, for example.

  As described above, the tuner control unit 31 selects a tuner other than the viewing tuner that selects the television signal of the channel of the viewing program (the television signal of the channel including the image data displayed on the display panel 17). As a background tuner, the background tuner causes all of the television signals of a plurality of channels broadcast in a predetermined broadcasting system to be selected and output in a time-sharing manner, and the buffer controller 32 outputs the television output by the background tuner. The encoded data of the program included in the John signal is temporarily stored in the switching buffer unit 18 for each program, and when the program switching operation is performed, the encoded data of the switching destination program is stored in the switching buffer unit. 18 to the decoding unit 15 and the decoding control unit 3 When the program switching operation is performed, the encoded data of the switching destination program supplied from the switching buffer unit 18 to the decoding unit 15 is decoded by the decoding unit 15, so that the program switching operation is performed. In this case, the image of the switching destination program can be displayed quickly without waiting for the encoded data of the intra picture of the switching destination program to be transmitted.

  In addition to the encoded image data, the encoded audio data can be processed in the same manner as the encoded image data. In this case, when a program switching operation is performed, the sound of the program to be switched to can be output quickly.

  In FIG. 6, when the processing returns from step S15 to step S12, the tuner control unit 31 receives the new reception tuner in the assignment of the channel to be received in the background to the new background tuner. The channel adjacent to the channel of the television signal to be switched (the channel of the program to be switched to) (hereinafter referred to as the “adjacent channel” as appropriate) is the first channel to receive in the background when receiving in time division. Can be assigned.

  In this case, in the new background tuner, the television signal of the adjacent channel is first received and stored in the switching buffer unit 18, so that the next program switching operation is performed. The latest image of the switching destination program can be immediately displayed on the display panel 17.

  That is, for example, when a program switching operation is performed in which a program on a channel adjacent to a viewing program channel is set as a switching destination program, a television signal of the adjacent channel is first transmitted in a new background tuner. And the latest image of the switching destination program (adjacent channel program) can be immediately displayed on the display panel 17.

In FIG. 2, the tuner unit 11 is configured by the _two tuners 11 ₁ and 11 _2. However, the tuner unit 11 can be configured by three or more tuners. As the number of tuners constituting the tuner unit 11 is increased, the number of background reception target channels assigned to each tuner can be reduced. As a result, in each tuner, the television signal of a certain channel can be time-divisionally divided. Can be shortened from the end of reception of the television signal until the start of time-division reception of the television signal of that channel. In this case, newer encoded data is stored in the switching buffer unit 18 as encoded data of each program, and a newer image can be displayed when a program switching operation is performed.

  Next, the TV shown in FIG. 2 can perform multi-display (multi-screen display) using the encoded data of each program stored in the switching buffer unit 18.

  That is, as described above, when the operation unit 19 is operated so as to perform multi display, the multi display control unit 34 in FIG. 2 controls the display control unit 16 and the like so as to perform multi display. Thus, the display control unit 16 causes the display panel 17 to perform multi-display for displaying an image on a multi-screen.

  FIG. 9 shows an example of the display screen of the display panel 17 in a state where multi-display is performed.

  In the multi-display, the display screen of the display panel 17 is divided into a plurality of small areas (hereinafter referred to as multi-display areas as appropriate), and each multi-display area is assigned to a program that is a multi-display target (multi-display target). . In each multi display area, an image of a program assigned to the multi display area is displayed.

  Here, in FIG. 9, the display screen of the display panel 17 is divided into 9 multi-display areas in total of 3 × 3 in the horizontal and vertical directions. Can be displayed.

  In the multi display, any of the programs whose encoded data is stored in the switching buffer unit 18 is assigned as a multi display target program to each of the nine multi display areas.

Therefore, as shown in FIG. 2, when the switching buffer unit 18 is composed of six switching buffers 18 ₁ to 18 ₆ that are smaller than nine, which is the number of multi-display areas, Six of the nine multi-display areas are assigned to six programs whose encoded data are stored in the switching buffers 18 ₁ to 18 ₆ , and each of the multi-display areas is assigned to each of the six multi-display areas. An image of the assigned program is displayed. In this case, for example, no image is particularly displayed in the multi-display area that is not assigned to the program among the nine multi-display areas.

  In the case where the switching buffer unit 18 is configured by a number of switching buffers greater than 9, which is the number of multi-display areas, for example, from among programs in which encoded data is stored in the switching buffer, As many programs as the number of multi-display areas are selected as multi-display target programs, and multi-display areas are assigned to the multi-display target programs.

  Further, the number of multi display areas can be set by the user operating the operation unit 19, for example. In addition, the number of multi-display areas can be set to, for example, the number of switching buffers constituting the switching buffer unit 18.

  Next, with reference to the flowchart of FIG. 10, a multi-display control process (multi-display control process) by the multi-display control unit 34 of FIG. 2 will be described.

In FIG. 10, the number of multi-display area (total), called a multi-screen display number N _m, when performing multi-display, the total number of programs being broadcast at a predetermined broadcasting system (program maximum number P) _Is called the total number of programs N _all . The total program number N _all can be recognized from the EPG, for example.

For example, when the user operates the operation unit 19 to perform multi-display, the multi-display control unit 34 determines in step S51 whether the total program number N _all is larger than the multi-screen display number N _m . Determine.

If it is determined in step S51 that the total program number N _all is not larger than the multi-screen display number N _m , the process proceeds to step S52, and the multi-display control unit 34 sets the program corresponding to the total program number N _all. All of the programs whose encoded data are stored in the switching buffer unit 18 are set as multi-display target programs, and the process proceeds to step S54.

If it is determined in step S51 that the total program number N _all is larger than the multi-screen display number N _m , the process proceeds to step S53, and the multi-display control unit 34 determines the total program number N _all. only the program, therefore, among the programs encoded data to the switching buffer unit 18 is stored, and select only the program number equal to the multi-screen display number N _m, only the program, a multi-display target The program proceeds to step S54.

In step S54, assuming that the number of programs set as the multi-display target program in step S52 or S53 is N _d (≦ N _m ), the multi-display control unit 34 _selects N _d multi-display target programs. respectively, assign the multi-display area of the multi-screen display number N _m by one, the process proceeds to step S55.

  In step S55, the multi-display control unit 34 sets, for example, 1 as an initial value to the variable n for counting the programs to be multi-displayed, and the process proceeds to step S56.

In step S56, the multi-display control unit 34 supplies one picture of the encoded data of the n-th program among the N _d multi-display target programs from the switching buffer unit 18 to the decoding unit 15. Then, the switching buffer unit 18 is controlled, and the process proceeds to step S57. As a result, in step S56, encoded data for one picture of the nth multi-display target program is supplied from the switching buffer unit 18 to the decoding unit 15.

  In step S57, the multi-display control unit 34 decodes the encoded data for one picture of the n-th multi-display target program supplied from the switching buffer unit 18 to the decoding unit 15. The process proceeds to step S58. Thereby, in step S57, the decoding unit 15 performs decoding using the encoded data for one picture of the nth multi-display target program from the switching buffer unit 18 as a decoding target, and the result is obtained. Image data for one picture of the n-th multi-display target program is supplied to the display control unit 16.

  In step S58, the multi-display control unit 34 resizes the image data for one picture of the n-th multi-display target program supplied from the decoding unit 15 to the display control unit 16, and the resized image data is The display control unit 16 is controlled to write to the display buffer 16A, and the process proceeds to step S59.

  As a result, in step S58, the display control unit 16 resizes the image data of the nth multi-display target program from the decoding unit 15 to image data of the size of the multi-display area, and the resized image data Then, the data is written into the storage area corresponding to the multi display area allocated to the nth multi display target program in the display buffer 16A. On the display panel 17, an image corresponding to the stored contents of the display buffer 16A is displayed.

At step S59, the determined multi-display control unit 34, whether equal to the number N _d of programs variable n is set to the multi display object for the program. In step S59, the case where it is determined to be equal to the number N _d of programs variable n is set to the multi display object for the program, i.e., image of N _d pieces of the multi-display target of the program, a multi-display one picture minute If so, the process returns to step S55, and the same process is repeated thereafter. As a result, the next one picture of each of the N _d multi-display target program images is displayed in a multi display.

On the other hand, in step S59, the case where it is not equal to the number N _d of programs variable n is set to the multi display object for the program, the process proceeds to step S60, the multi-display control unit 34, a variable n After incrementing by 1, the process returns to step S56, and the same process is repeated thereafter.

The process of step S56 to S58 is, by repeating only N _d times, the display panel 17, one picture of N _d pieces of the multi-display target of the program, a multi-screen N _d number of multi-in the display number N _m Each is displayed (multi-displayed) in the multi-display area to which the program to be displayed is assigned.

As described above, according to the control of the multi-display control unit 34, the display control unit 16 selects two or more N _d programs among the plurality of programs whose encoded data is stored in the switching buffer unit 18, When displaying an image obtained by decoding the encoded data of the multi-display target program as a multi-display target program (hereinafter also referred to as a decoded image as appropriate) in the multi-display area of the display panel 17, In each multi display area, it is possible to realize a multi screen (hereinafter, referred to as a “video multi screen” as appropriate) in which a moving image is displayed as an image of a program to be displayed.

  Then, by applying the video multi-screen to, for example, an EPG, it is possible to provide an EPG that switches the viewing program to the program when the video of the program displayed in the multi-display area is specified. Become.

  Also, by setting the slot period T to a certain length, the time for displaying the video in each multi display area of the video multi screen is extended to some extent, so that the video displayed in each multi display area can be referred to as a video thumbnail. Can be used.

By the way, assuming that the decoding unit 15 has a function of decoding encoded data for one picture into a decoded image in a display period (for example, 1/30 second) of one picture, for example, N _d programs However, in the case of a multi-display target program, in one multi-display area of the moving image multi-screen, the decoded image of one picture is changed (updated) to the decoded image of another (next) picture. N It takes time only for the _d picture display period.

Therefore, when the number N _d of the multi-display target of the program is increased, in each multi-display area of the video multi-screen, it is difficult to display moving smooth motion.

  Therefore, in the multi-display, the decoding unit 15 can display only a low-frequency component, not all of the encoded data, so that a moving image with smooth motion can be displayed on the moving image multi-screen. .

  That is, in the MPEG system, image data is subjected to a process of converting into a frequency domain such as DCT (Discrete Cosine Transform) for each block of 8 × 8 pixels or 4 × 4 pixels in the horizontal and vertical directions, and a frequency component called a DCT coefficient It is said. The decoding unit 15 can decode not only all of the DCT coefficients that are the frequency components but also only the low-frequency (low frequency component) DCT coefficients.

  With reference to FIG. 11, the process of the decoding unit 15 for decoding only the low-frequency DCT coefficients will be described.

  FIG. 11 shows a block of 8 × 8 DCT coefficients and a block of 8 × 8 pixels.

  When a block of 8 × 8 pixels is DCT processed, a block of 8 × 8 DCT coefficients is obtained. Then, when a block of 8 × 8 DCT coefficients is subjected to inverse DCT processing, an 8 × 8 pixel block is obtained as shown by a dotted line in FIG.

  The decoding unit 15 reverses only the 4 × 4 DCT coefficients in the upper left, which are low-frequency DCT coefficients in the block of 8 × 8 DCT coefficients, for example, hatched in FIG. DCT can be processed. In this case, a 4 × 4 pixel block obtained by smoothing an 8 × 8 pixel block is obtained by inverse DCT processing.

  The lower part of FIG. 11 shows a decoded image obtained when inverse DCT processing is performed on all blocks of 8 × 8 DCT coefficients, and 4 × 4 DCT coefficients in a low band among blocks of 8 × 8 DCT coefficients. 3 shows a decoded image obtained by performing inverse DCT processing only on the image.

  Now, assuming that all blocks of 8 × 8 DCT coefficients have been subjected to inverse DCT processing, as shown by a dotted line in the lower part of FIG. When only the low frequency 4 × 4 DCT coefficients in the block of DCT coefficients are subjected to inverse DCT processing, as shown by the solid line at the bottom of FIG. A decoded image of 960 × 540 pixels is obtained.

  Accordingly, when only the low frequency 4 × 4 DCT coefficients are subjected to inverse DCT processing, the resolution of the decoded image is deteriorated as compared with the case where all blocks of 8 × 8 DCT coefficients are subjected to inverse DCT processing. . However, in multi-display, the decoded image is displayed in a multi-display area, which is a small area that divides the display screen of the display panel 17, and degradation of the resolution of the decoded image does not cause a problem.

  As described above, when only the low-frequency DCT coefficients are decoded in the decoding unit 15, the load required for decoding is reduced as compared with the case where all the DCT coefficients are decoded.

  In addition, the decoding of MPEG data is not limited to DCT operation, but the temporal accuracy prediction such as motion compensation and the spatial direction blocking filter etc. to the pixel accuracy equivalent to the decoding of the entire DCT after decoding the low-frequency DCT coefficients It is executed after conversion. Therefore, the decoding unit 15 can perform decoding of encoded data for one picture in a shorter time as compared with a normal picture decoding method in which all DCT coefficients are decoded. As a result, it is possible to secure a calculation resource for the data in the channel buffer at a higher speed, and as a result, it is possible to display a moving image with smooth motion.

  The present invention has been described with reference to the case where the present invention is applied to a TV. However, the present invention is not limited to a TV, but includes, for example, a signal including a television signal of a plurality of channels, such as a recording device (recorder) that does not include the display panel 17. It is applicable to a signal processing device that processes

  In FIG. 1, the demodulation unit 12, the error correction unit 13, the demultiplexer unit 14, and the decoding unit 15 can be configured by (dedicated) hardware, for example, a DSP (Digital Signal that executes a program) It can also be configured by a processor (computer) such as a processor.

Further, the number N of the switching buffers 18 ₁ to 18 _N constituting the switching buffer unit 18 may be less than the maximum program number P. In this case, however, a program that cannot store the encoded data and a program that can be stored are generated in the switching buffer unit 18, and the switching destination program stores the encoded data in the switching buffer unit 18. When the program is stored, the image of the program to be switched to can be quickly displayed.

  Here, in the present specification, the processing steps for describing a program for causing the computer (the CPU 22 in FIG. 1) to perform various processes do not necessarily have to be processed in chronological order in the order described in the flowchart. In addition, processing that is executed in parallel or individually (for example, parallel processing or processing by an object) is also included.

  Further, the program may be processed by one computer or may be distributedly processed by a plurality of computers.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a block diagram which shows the structural example of one Embodiment of TV to which this invention is applied. It is a block diagram which shows the structural example of TV which has _two tuners 11 ₁ and 11 ₂ and six switching buffers 18 ₁ to 18 ₆ . Tuner 11 ₁ and 11 _2, and is a timing chart for explaining the operation of the switching buffer 18 ₁ to 18 _6. No switching buffer 18 _first buffer portion 18 for switching to a view showing a 18 ₆ storage contents of. Tuner 11 ₁ and 11 ₂ when the operation of the program switching is performed, and is a timing chart for explaining the operation of the switching buffer 18 ₁ to 18 _6. It is a flowchart explaining a tuner control process. It is a flowchart explaining a buffer control process. It is a flowchart explaining a decoding control process. It is a figure which shows the example of the display screen of the display panel 17 of the state of a multi display. It is a flowchart explaining a multi-display control process. It is a figure explaining the process of the decoding part 15 which decodes only a low frequency DCT coefficient.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 tuner part, 11 ₁ thru | or 11 _M tuner, 12 demodulation part, 13 error correction part, 14 demultiplexer part, 15 decoding part, 16 display control part, 16A display buffer, 17 display panel, 18 switching buffer part, 18 ₁ to 18 _N switching buffer, 19 operation section, 20 control section, 21 EEPROM, 22 CPU, 23 RAM, 31 tuner control section, 32 buffer control section, 33 decode control section, 34 multi display control section

Claims (8)

In a signal processing apparatus for processing a signal including television signals of a plurality of channels,
Two or more channel selection means for selecting and outputting a television signal of a predetermined channel from the signals including the television signals of the plurality of channels;
Decoding means for decoding program data included in the television signal output by the channel selection means, and outputting image data;
Display control means for causing the display means to display the image data output by the decoding means;
The channel selection means other than the channel selection means for selecting the television signal of the channel including the image data displayed on the display means is used as the background channel selection means, and the background channel selection means includes the plurality of channels. Channel selection control means for selecting and outputting a television signal of time-division,
The program data included in the television signal output by the background channel selection means is temporarily stored in the storage means for each program, and the program whose image data is displayed on the display means is switched to another program A storage control means for supplying data of the other program from the storage means to the decoding means when a switching operation is performed;
A signal processing apparatus comprising: a decoding control unit that causes the decoding unit to decode data of the other program supplied from the storage unit to the decoding unit when the program switching operation is performed. The program data is encoded data obtained by intra-coding or inter-coding the image data of a picture,
The signal processing apparatus according to claim 1, wherein the storage control unit starts supplying the program data stored in the storage unit to the decoding unit from an intra-coded picture. When the channel selection control means starts receiving the television signals of the plurality of channels in a time division manner, the channel selection control means first selects a television signal of a channel including image data displayed on the display means. The signal processing apparatus according to claim 1, wherein the background channel selection unit selects a television signal of a channel adjacent to the channel of the television signal selected by the selected channel selection unit. The signal processing apparatus according to claim 1, wherein the display control unit further causes the display unit to display, on a multi-screen, image data obtained by decoding data of two or more programs stored in the storage unit. The program data includes a frequency component of the image data,
The signal processing apparatus according to claim 4, wherein the decoding unit decodes only low frequency components of data of two or more programs stored in the storage unit. The channel selection control means sets a period for selecting a television signal of one channel, and causes the background channel selection means to select each of the television signals of the plurality of channels in a time division manner for each period. The signal processing apparatus according to claim 1. In a signal processing method of a signal processing apparatus for processing a signal including television signals of a plurality of channels,
The signal processing device includes:
Two or more channel selection means for selecting and outputting a television signal of a predetermined channel from the signals including the television signals of the plurality of channels;
Decoding means for decoding program data included in the television signal output by the channel selection means, and outputting image data;
Display control means for causing the display means to display the image data output by the decoding means,
The channel selection means other than the channel selection means for selecting the television signal of the channel including the image data displayed on the display means is used as the background channel selection means, and the background channel selection means includes the plurality of channels. The TV signal is selected and output in time division,
The program data included in the television signal output by the background channel selection means is temporarily stored in the storage means for each program, and the program whose image data is displayed on the display means is switched to another program When the switching operation is performed, the data of the other program is supplied from the storage unit to the decoding unit,
A signal processing method including a step of causing the decoding means to decode data of the other program supplied from the storage means to the decoding means when the program switching operation is performed. In a control program to be executed by a computer that controls a signal processing device that processes signals including television signals of a plurality of channels,
The signal processing device includes:
Two or more channel selection means for selecting and outputting a television signal of a predetermined channel from the signals including the television signals of the plurality of channels;
Decoding means for decoding program data included in the television signal output by the channel selection means, and outputting image data;
Display control means for causing the display means to display the image data output by the decoding means,
The computer,
The channel selection means other than the channel selection means for selecting the television signal of the channel including the image data displayed on the display means is used as the background channel selection means, and the background channel selection means includes the plurality of channels. Channel selection control means for selecting and outputting a television signal of time-division,
The program data included in the television signal output by the background channel selection means is temporarily stored in the storage means for each program, and the program whose image data is displayed on the display means is switched to another program A storage control means for supplying data of the other program from the storage means to the decoding means when a switching operation is performed;
A program that, when the program switching operation is performed, causes the decoding means to function as decoding control means for decoding data of the other program supplied from the storage means to the decoding means.

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