JP2011055441A - Set top box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make operation convenient when performing reserved recording of videos of digital broadcast in an analog video-recording device. <P>SOLUTION: An identification data adder 120 adds identification data to a signal of a receiving channel received by a tuner body 110 and obtains a signal with identification data. An RF converter 130 converts the signal with identification data into an RF signal of analog broadcast. The RF signal obtained by the RF converter 130 is line-output through an RF signal output terminal 152 to a video-recording device of analog broadcast, and an output signal of the video-recording device is line-input through a feedback signal input terminal 154 to a control unit 140. The control unit 140 detects identification data from the output signal of the video-recording device and changes settings of the receiving channel in accordance with detection results. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a set top box that enables recording of a digital broadcast program with an analog recording device.

  As the transition from analog broadcasting to digital broadcasting progresses, set-top boxes for viewing and recording digital broadcasts are being used on analog televisions and analog recording devices that are currently popular.

  Here, various attempts have been made to improve convenience when recording a digital broadcast program using a set-top box and an analog recording device.

  For example, in Patent Document 1, a monitoring signal is sent to a VTR that is an analog recording device to detect the operation state of the VTR, and the power supply of the main body is controlled on / off based on the detection result. There is disclosed a CS / BS tuner that enables reservation recording.

  This CS / BS tuner has an input terminal for inputting an output signal of the VTR, and sends a monitoring signal to the VTR when the power of the main body is turned off, and is also inputted through the input terminal. The presence or absence of a monitoring signal in the output signal from the VTR is detected. If the monitoring signal is not detected, the monitoring operation is continued. If the monitoring signal is detected, the power of the main body is turned on and the signal output to the VTR is switched to the video signal. Thereafter, the presence / absence of a video signal in the output signal from the VTR is detected, and when there is no video signal, the main body is turned off.

  According to the CS / BS tuner, if the reservation recording is set on the VTR side, the tuner side is turned on when the VTR side starts recording, and the tuner side is turned off when the VTR side recording ends. The power on / off setting for the reserved recording is unnecessary on the tuner side.

Japanese Patent No. 2700020

  However, it is not possible to correctly realize reserved recording only by reservation setting on the analog recording device side only by providing a function capable of turning on / off the main body according to recording start / end of the analog recording device. It is necessary to set the channel on the set top box side in accordance with the reserved recording channel set by the analog recording device, and the operation is complicated.

  One aspect of the present invention is a set top box. The set top box includes an identification data adding unit, a conversion unit, an output terminal, an input terminal, and a control unit.

  The identification data adding unit adds identification data to a signal of a set reception channel among a plurality of channels of digital broadcasting.

  The conversion unit converts the signal with identification data obtained by the identification data adding unit into an analog broadcast RF signal, and the output terminal outputs the RF signal to an analog broadcast recording device. The input terminal inputs an output signal of the recording device.

  The control unit detects identification data for the output signal of the recording device from the input terminal, and changes the setting of the reception channel according to the detection result.

  In addition, a program in which the set-top box of the above aspect is replaced with a system or method and a program that causes a computer to execute a part of the processing of the set-top box are also effective as an aspect of the present invention.

  According to the technology of the present invention, it is possible to improve the operability when a digital broadcast video is reserved and recorded by an analog recording device.

It is a figure which shows the set top box concerning the 1st Embodiment of this invention. It is a flowchart which shows the flow of a process in the set top box shown in FIG. It is a figure for demonstrating addition of identification data (the 1). It is a figure for demonstrating addition of identification data (the 2). It is a figure for demonstrating addition of identification data (the 3). It is a figure which shows the set top box concerning the 2nd Embodiment of this invention. It is a flowchart which shows the flow of a process in the set top box shown in FIG. It is a flowchart which shows the flow of a process in the set top box concerning the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Each element described in the drawings as a functional block for performing various processes can be configured by a CPU, a memory, and other circuits in terms of hardware, and a program loaded in the memory in terms of software. Etc. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof, and is not limited to any one.

<First Embodiment>
FIG. 1 shows a set top box 100 according to a first embodiment of the present invention. The set-top box 100 is, for example, a digital broadcast tuner, which converts a digital broadcast IF signal into an analog broadcast RF signal and enables recording of a digital broadcast program by an analog broadcast recording device. As shown in the figure, the set top box 100 includes a broadcast wave input terminal 102, a tuner main body 110, an identification data adding unit 120, an RF converter 130, a control unit 140, an RF signal output terminal 152, and a feedback signal input. A terminal 154 is provided. The control unit 140 includes an analysis unit 142.

  The broadcast wave signal S0 from the digital broadcast antenna is input to the tuner main body 110 via the broadcast wave input terminal 102. The tuner main body 110 selects a channel according to the reception channel control signal ctr from the control unit 140, and includes a signal (reception channel signal S1) of the channel (reception channel) specified by the reception channel control signal ctr included in the broadcast wave signal S0. Is output to the identification data adding unit 120.

  The identification data adding unit 120 adds identification data to the reception channel signal S1 from the tuner main body 110 to obtain a signal S2 with identification data. In the present embodiment, the identification data is different for each channel, and the identification data adding unit 120 adds identification data corresponding to the channel of the reception channel signal S1 to the reception channel signal S1.

  The signal S2 with identification data is output to the RF converter 130. The RF converter 130 is a conversion unit that converts a digital broadcast signal into an RF signal. Here, the signal S2 with identification data is converted into an RF signal S3. This RF signal S3 is line-outputted to an analog broadcast recording device (not shown) via an RF signal output terminal 152.

  Further, the output signal of the recording device (hereinafter referred to as feedback signal R) is line-inputted to the analysis unit 142 of the control unit 140 via the feedback signal input terminal 154.

  The analysis unit 142 analyzes the feedback signal R and detects whether or not data corresponding to the identification data added by the identification data adding unit 120 is included in the feedback signal R. The data corresponding to the identification data added by the identification data adding unit 120 included in the feedback signal R is the same as the identification data except that the data format is different. In the description of FIG.

  The control unit 140 changes the setting of the reception channel based on the analysis result of the analysis unit 142. Specifically, if there is no identification data in the feedback signal R as a result of analysis by the analysis unit 142 (including the case where the feedback signal R is a blue back signal), until the identification data is detected in the feedback signal R. The channel specified by the reception channel control signal ctr is changed.

  The operation of the set top box 100 will be described in detail with reference to the flowchart of FIG. For the sake of easy understanding, a case will be described as an example in which the scheduled recording of the recording of channel ch4 is set on the recording device (not shown). Hereinafter, a channel set on the recording device side is referred to as an analog channel, and a digital broadcast channel is referred to as a digital channel. In this example, there are ten digital channels D1 to D10, and these digital channels correspond to the analog channels ch1 to ch10 on the recording device side, respectively.

As shown in FIG. 2, in the set top box 100, the control unit 140 first sets the reception channel to an initial value (S102). This initial value may be any one of the digital channels D1 to D10 according to the specification of the set box, or may be a channel that was set when the power was turned off last time. Here, it is assumed that the initial value of the reception channel is “D1”.
The control unit 140 outputs a reception channel control signal ctr indicating the set reception channel to the tuner main body 110 and the identification data adding unit 120.

  The tuner main body 110 selects a channel according to the reception channel control signal ctr, and outputs a channel signal (reception channel signal S1) indicated by the reception channel control signal ctr included in the broadcast wave signal S0 to the identification data adding unit 120 ( S104). Here, the reception channel signal S1 is a signal of the digital channel D1.

  The identification data adding unit 120 stores identification data corresponding to each of the digital channels D1 to D10, and corresponds to the channel indicated by the reception channel control signal ctr with respect to the reception channel signal S1 from the tuner main body 110. The identification data with the identification data is added to obtain the signal S2 with identification data (S106). Here, the identification data-added signal S2 is obtained by adding identification data of the digital channel D1 to the signal of the digital channel D1.

  The RF converter 130 converts the identification data-added signal S2 from the identification data adding unit 120 into an RF signal to obtain an RF signal S3, and outputs the RF signal S3 to the recording device via the RF signal output terminal 152 (S108).

  A recording device (not shown) is set to record the RF signal of ch4 (that is, D4). At this time, since the RF signal S3 from the RF converter 130 is the RF signal of the digital channel D1, the recording device has no target to record and outputs, for example, a blue back signal. A feedback signal R (here, a blue back signal) from the recording device is input to the control unit 140 via the feedback signal input terminal 154.

  The analysis unit 142 in the control unit 140 analyzes the feedback signal R and detects the presence or absence of identification data corresponding to one of the digital channels D1 to D10 in the feedback signal R (S110). Here, since the feedback signal R is a blueback signal, the analysis unit 142 obtains a detection result that “there is no identification data” in the feedback signal R (S120: No).

  When there is no identification data in the feedback signal R as a result of analysis by the analysis unit 142 (S120: No), the control unit 140 changes the reception channel to another digital channel (S130). In the present embodiment, as an example, control unit 140 changes the order of D1 to D10 when changing the setting of the reception channel. Therefore, here, the reception channel is changed to D2, and the reception channel control signal ctr indicates the digital channel D2.

  With the reception channel set to D2, the processing from step S104 to step S130 is repeated, and the reception channel is changed to D3.

  With the reception channel set to D3, the processing from step S104 to step S130 is repeated, and the reception channel is changed to D4.

  The processing of step S104 to step S108 is performed in a state where the reception channel is set to D4, and the RF signal S3 corresponding to the signal of the digital channel D4 to which the identification data is added is recorded via the RF signal output terminal 152. Is output.

  At this time, the recording device set to record the ch4 (ie, D4) RF signal records the RF signal S3. The recorded video is input to the control unit 140 as a feedback signal R via the feedback signal input terminal 154.

  The analysis unit 142 analyzes the feedback signal R and detects that there is identification data in the feedback signal R (S110, S120: Yes).

  Thereby, the change of the reception channel by the control unit 140 is completed, and the program of the channel ch4 (D4) reserved for recording on the recording device side is recorded.

Here, a method of adding identification data by the identification data adding unit 120 will be described.
In the present embodiment, identification data adding section 120 adds identification data to an invisible region of an image frame included in reception channel signal S1. This will be described with reference to FIG.

  In general, an image frame has a region (visible region) that is visible to the viewer and a region (invisible region) that is not visible to the viewer. In the example of FIG. 3, the shaded area is a visible area, and the other areas are invisible areas. In the present embodiment, as shown in FIG. 3, an area for storing identification data (identification data storage area in FIG. 3) is located in an invisible area.

  Specifically, for example, a predetermined data format is used in the vertical blanking period described in “Video ID signal transmission method using VBI” defined by EIAJ CPR-1204 (EIAJ: Japan Electronic Machinery Manufacturers Association). Identification data is added according to the specification.

  In the NTSC (National Television System Committee) standard, in the case of an odd field, the first scanning line in the vertical blanking period is the first scanning line, and the first effective image is the 20th scanning line. In the case of an even field, the first scanning line in the vertical blanking period is 263, but since the number of scanning lines is an odd number of 525, the vertical blanking period starts from the center of the 263th. The first effective video in the even field is from the center of the 283th video.

  FIG. 4 shows an example of arrangement of digital signals in the vertical blanking period in the NTSC luminance signal. As shown in the figure, a 73 IRE reference signal Ref and a 20-bit digital signal represented by an amplitude 70 IRE or 0 IRE are arranged in the vertical blanking period of the luminance signal. This 20-bit digital signal is encoded and transmitted.

  In this embodiment, identification data is added to the vertical blanking period. That is, identification data is added before the 20th scanning line in the case of an odd field, and before the latter half of the 283th scanning line in the case of an even field. Specifically, a part of a 20-bit digital signal arranged in the vertical blanking period shown in FIG. 4 is used as identification data.

  In the “video ID signal transmission method using VBI”, an identification code is assigned to the waveform of the identification data signal. The format of the identification code follows the code assignment shown in FIG. When the identification code WORD1 = 4′b1011 to 4′b1110, the contents propagated by 8 bits of WORD2 are undefined in the standard, and an arbitrary value can be set.

  In the present embodiment, identification data for each channel is defined using the undefined portion where an arbitrary value can be set. For example, the identification data can be added so that the channel D1 is 8'h01 and the channel D2 is 8'h02.

  According to the set-top box 100 of the present embodiment, the reception channel is set in accordance with the recording target channel set on the analog recording device side, so that the channel setting is set on the analog recording device side when performing scheduled recording. You can record the program of the correct channel just by doing.

  In addition, even if the channel settings on the set box side and the recording device side do not match, recording will not be possible due to a setting error on the receiving channel on the set box side because the program is recorded on the channel set on the recording device side. It is possible to avoid problems such as

  In this embodiment, since identification data is added to an invisible region of an image frame, it is possible to prevent the viewer from seeing identification data that should not be shown to the viewer.

  Furthermore, since identification data is added by a method defined by a standard such as EIAJ CPR-1204, malfunctions due to noise or the like when receiving identification data can be reduced, and identification data can be reliably detected. Therefore, it is possible to reliably match the reception channel with the channel set on the recording device side.

  Further, by adding identification data according to the standard, a set-top box compliant with the standard can be mounted, and it is simple and inexpensive.

<Second Embodiment>
FIG. 6 shows a set-top box 200 according to the second embodiment of the present invention. The set-top box 200 is also a digital broadcast tuner, and includes a broadcast wave input terminal 202, a tuner main body 210, an identification data adding unit 220, a conversion unit 230, a control unit 240, an RF signal output terminal 252, and a feedback. A signal input terminal 254 is provided. The conversion unit 230 includes an RF converter 232 and an RF mixer 234, and the control unit 240 includes an analysis unit 242.

  The broadcast wave signal S0 from the digital broadcast antenna is input to the tuner main body 210 via the broadcast wave input terminal 202. In accordance with the reception channel control signal ctr1 from the control unit 240, the tuner main body 210 outputs a signal of the reception channel specified by the reception channel control signal ctr1 included in the broadcast wave signal S0 to the identification data adding unit 220.

  The identification data adding unit 220 adds identification data to the reception channel signal S1 from the tuner main body 210 to obtain a signal S2 with identification data. In the present embodiment, the details will be described later, but the identification data adding unit 220 adds the reception channel signal S1 with only the identification data of the reception channel and the reception depending on the control of the control unit 240. In some cases, identification data of each channel is added to the channel signal S1. When identification data for each channel is added, the signal S2 with identification data shown in FIG. 6 is a signal for a plurality of channels. The specific method of adding identification data by the identification data adding unit 220 is the same as the method of the identification data adding unit 120 of the set top box 100 shown in FIG. 1, and detailed description thereof is omitted here.

  A signal S 2 with identification data from the identification data adding unit 220 is output to the conversion unit 230. In the conversion unit 230, the RF converter 232 converts the signal S2 with identification data from the identification data adding unit 220 into an RF signal, obtains an RF signal S3, and outputs the RF signal S3 to the RF mixer 234. The RF mixer 234 mixes the RF signal S3 into one RF signal S4 when the RF signal S3 is for a plurality of channels in accordance with the conversion unit control signal ctr2 from the control unit 240, and passes the RF signal S3 through the RF signal output terminal 252. Output to a recording device (not shown) for analog broadcasting. When the RF signal S3 is only for one channel, the RF mixer 234 does not perform the mixing operation and outputs the RF signal S3 as it is.

  In addition, the output signal (feedback signal R) of the recording device is input to the analysis unit 242 of the control unit 240 via the feedback signal input terminal 254.

The analysis unit 242 analyzes the feedback signal R and detects which channel the identification data included in the feedback signal R corresponds to.
The control unit 240 changes the setting of the reception channel based on the analysis result of the analysis unit 242.

  The operation of each component of the set top box 200 will be described in detail with reference to the flowchart of FIG. For the sake of easy understanding, a case will be described as an example in which the scheduled recording of the recording of channel ch4 is set on the recording device (not shown). Also, there are ten digital channels D1 to D10, and these digital channels correspond to the analog channels ch1 to ch10 on the recording device side, respectively.

  As shown in FIG. 7, in the set top box 200, the control unit 240 first sets the reception channel to an initial value (S150). Here, it is assumed that the initial value of the reception channel is “D1”.

  The control unit 240 outputs the first control signal ctr1 to the tuner main body 210 and the identification data adding unit 220, and outputs the second control ctr2 to the identification data adding unit 220 and the converting unit 230.

The first control signal ctr1 indicates the set reception channel and is the same as the reception channel control signal ctr in the set-top box 100 of the first embodiment. For example, when the second control signal ctr2 is “Hi”, the identification data adding unit 220 “adds identification data of all channels” and the conversion unit 230 “mix”. When it is “Low”, “Add only identification data of reception channel” is indicated to the identification data adding unit 220, and “Do not mix” is indicated to the conversion unit 230.
Here, the control unit 240 outputs a first control signal indicating “D1” and a second control signal ctr2 indicating “Hi”.

  The tuner main body 210 selects a channel according to the first control signal ctr1, and outputs the channel signal (reception channel signal S1) indicated by the first control signal ctr1 included in the broadcast wave signal S0 to the identification data adding unit 120. (S151). Here, the reception channel signal S1 is a signal of the digital channel D1.

  Since the second control signal ctr2 is “Hi”, the identification data adding unit 220 adds the identification data of each of the digital channels D1 to D10 to the signal of the reception channel (D1) from the tuner main body 210, respectively. Thus, a signal S2 with identification data of 10 channels is obtained (S152). Further, the identification data adding unit 220 outputs the relationship information P indicating the correspondence between the channel and the identification data to the analysis unit 242.

  The RF converter 232 converts the signal S2 with identification data of each channel from the identification data adding unit 220 into an RF signal S3. Since the second control signal ctr2 is “Hi”, the RF mixer 234 mixes these RF signals S3 into one RF signal S4 (S154).

  The RF signal S4 is output to the recording device via the RF signal output terminal 252. Since the recording device (not shown) is set to record the ch4 (that is, D4) program, it records the ch4 signal included in the RF signal S4. The recorded signal is input to the control unit 240 via the feedback signal input terminal 254 as a feedback signal R.

  The analysis unit 242 in the control unit 240 analyzes the feedback signal R, and detects a channel corresponding to the identification data included in the feedback signal R based on the relationship information P from the identification data adding unit 220 (S156). Here, D4 corresponding to the identification data is detected.

  For example, each identification data in the relationship information P may be output to the control unit 240 after the identification data adding unit 220 converts the data into the data format in the feedback signal R, or the control unit 240 adds the identification data. The identification data included in the relationship information P received from the unit 220 may be converted into a data format in the feedback signal R and used for detection.

  The control unit 240 changes the setting of the reception channel according to the detection result by the analysis unit 242. Specifically, only the channel detected by the analysis unit 242 is set as a reception channel (S160). Here, the reception channel is set to D4. The control unit 240 outputs the first control signal ctr1 indicating “D4” to the tuner main body 210 and the identification data adding unit 220, and sets the second control signal ctr2 to “Low”.

  Thereafter, the tuner main body 210 outputs the signal of the digital channel D4 included in the broadcast wave signal S0 as the reception channel signal S1 to the identification data adding unit 220 (S162), and the identification data adding unit 220 outputs the channel D4 to the reception channel signal S1. The identification data-added signal S2 is output to the conversion unit 230 (S162, S164). The RF converter 232 of the conversion unit 230 converts the signal S2 with identification data into the RF signal S3, and the RF mixer 234 does not perform the mixing process and outputs the RF signal S3 as it is (S166).

  Thereby, the change of the reception channel by the control unit 240 is completed, and the program of the channel ch4 (D4) reserved for recording on the recording device side is recorded.

  The set top box 200 of the present embodiment can obtain the same effects as the set top box 100 of the first embodiment.

  Furthermore, the set-top box 200 can adjust the reception channel to the channel set on the recording device side with only one setting change, so that the processing is fast.

<Third Embodiment>
The third embodiment of the present invention is also a set top box. This set-top box has a function corresponding to continuous recording accompanied by change of recording channel on the analog recording device side. This function can be added to both the set-top box 100 and the set-top box 200. For example, the set-top box 100 added with this function is the set-top box of the third embodiment. A box.

  For ease of understanding, the third embodiment will be described using each component of the set top box 100 shown in FIG.

  FIG. 8 is a flowchart showing a flow of processing by the set top box according to the third embodiment of this invention. In FIG. 8, steps S102 to S130 are the same as steps S102 to S130 in FIG. 2 showing the flow of processing by the set top box 100 of the first embodiment.

  Step S200 in FIG. 8 is a process for dealing with continuous recording that involves changing the recording channel on the recording device side. In the present embodiment, the control unit 140 detects the identification data from the feedback signal R from the recording device, that is, the reception channel set on the set box side matches the recording channel set on the recording device side. Even after (S120: Yes), detection of the presence or absence of identification data by analysis of the feedback signal R from the recording device is continued (S200). If there is identification data in the feedback signal R as a result of the detection, the control unit 140 continues to detect the presence or absence of identification data in the feedback signal R (S202: Yes, S200 ~). On the other hand, when there is no identification data in the feedback signal R, the control unit 140 further detects the presence or absence of an output signal from the recording device, that is, the feedback signal R (S202: NO, S204).

  When there is no feedback signal R (S204: No), the control unit 140 determines that the recording device has been turned off and ends the process.

  On the other hand, when the feedback signal R is present, the control unit 140 determines that the recording channel has been changed on the recording device side, and proceeds to step S102 (S204: Yes, S102-). As a result, processing for adjusting the reception channel of the set top box to the changed channel is performed on the recording device side, and the recording device can record the program of the changed channel.

  The set top box according to the third embodiment can cope with continuous recording accompanied by a change in recording channel on the recording device side in addition to the effects obtained by the set top box 100 according to the first embodiment, and is more convenient. It is.

  The present invention has been described above based on the embodiment. The embodiment is an exemplification, and various modifications, increases / decreases, and combinations may be made to the above-described embodiments without departing from the gist of the present invention. It will be understood by those skilled in the art that modifications in which these changes, increases / decreases, and combinations are also within the scope of the present invention.

  For example, in the first embodiment, the identification data is different for each digital broadcasting channel, and the identification data adding unit 120 adds identification data corresponding to the reception channel. For example, the identification data adding unit 120 may use identification data that is predetermined fixed data, and add the same fixed data when any channel is set as a reception channel. In this case, the control unit 140 also changes the setting of the reception channel until the fixed data is detected from the feedback signal. By doing so, it is not necessary to change the identification data according to the reception channel, so that a simpler configuration can be realized.

  Further, for example, in the second embodiment, the control unit 240 is notified of the correspondence between the channel and the identification data based on the relationship information P from the identification data adding unit 220. The control portion 240 may have information indicating this correspondence in advance. In this case, each identification data included in the relationship information may be previously converted into a data format in the feedback signal R, or the control unit 240 converts the identification data into a data format in the feedback signal R upon detection. You may make it do.

  For example, in each of the embodiments described above, identification data is added to an image signal included in a video signal. However, for example, identification data may be added to an audio signal included in a video signal.

100 set top box 102 broadcast wave input terminal 110 tuner main body 120 identification data adding unit 130 RF converter 140 control unit 142 analyzing unit 152 RF signal output terminal 154 feedback signal input terminal 200 set top box 202 broadcast wave input terminal 210 tuner main body 220 identification Data addition unit 230 Conversion unit 232 RF converter 234 RF mixer 240 Control unit 242 Analysis unit 252 RF signal output terminal 254 Feedback signal input terminal

Claims (12)

An identification data adding unit for adding identification data to the set digital broadcast reception channel signal;
A conversion unit for converting the signal with identification data obtained by the identification data adding unit into an RF signal of analog broadcasting;
An output terminal for outputting the RF signal to an analog broadcast recording device;
An input terminal for inputting an output signal of the recording device;
A set-top box comprising: a control unit that detects identification data from an output signal of the recording device from the input terminal and changes a setting of a reception channel according to a detection result. The identification data is predetermined fixed data,
The set-top box according to claim 1, wherein the control unit changes a setting of a reception channel until the fixed data is detected from an output signal of the recording device from the input terminal. The identification data is different for each digital broadcast channel,
The identification data adding unit adds identification data corresponding to a reception channel,
The set-top box according to claim 1, wherein the control unit changes a setting of a reception channel until the identification data is detected from an output signal of the recording device from the input terminal. The identification data is different for each digital broadcast channel,
The identification data adding unit adds identification data of each channel to the signal of the reception channel to obtain a plurality of signals with identification data;
The conversion unit converts each of the plurality of signals with identification data into an RF signal and performs a mixing process of mixing each RF signal obtained by the conversion,
The set top according to claim 1, wherein the control unit changes the setting so that a channel corresponding to identification data detected from an output signal of the recording device from the input terminal becomes a reception channel. box. The identification data adding unit outputs relationship information indicating a correspondence relationship between channels and identification data to the control unit,
The set-top box according to claim 4, wherein the control unit performs the detection based on the relationship information.   6. The set top box according to claim 5, wherein the identification data adding unit outputs the relation information obtained by converting each identification data into a data format in an output signal of the recording device to the control unit.   The said control part converts each identification data included in the said relationship information from the said identification data addition part into the data format in the output signal of the said video recording apparatus, and performs the said detection. Set top box.   The set-top box according to claim 4, wherein the control unit has relationship information indicating a correspondence relationship between channels and identification data, and performs the detection based on the relationship information.   2. The control unit according to claim 1, wherein after the setting is changed, the identification data adding unit adds only identification data corresponding to a reception channel, and the conversion unit controls the mixing process to stop. The set top box according to any one of 4 to 8.   The set top box according to any one of claims 1 to 9, wherein the identification data adding unit adds identification data to an invisible region of an image frame included in a signal of a reception channel.   The set top box according to claim 10, wherein the identification data adding unit adds identification data during a vertical blanking period of a signal of a reception channel.   The set top box according to any one of claims 1 to 9, wherein the identification data adding unit adds identification data to an audio signal included in a signal of a reception channel.

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