Reception apparatus

Abstract

To enable a transmitter device to read appropriate device information (EDID) from a receiver device with a reduced burden on a user.SOLUTION: A reception apparatus includes a memory unit that stores first device information and second device information, and a communication unit that communicates with an external device. A control unit determines to cause the external device to read the second device information, on the basis of reception of a rewrite signal for the first device information from the external device. It is possible to cause the external device (a transmitter device) to read appropriate device information (EDID) from a receiver device (a reception device) with a reduced burden on a user, and thus, user-friendliness can be increased.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This technology relates to a receiving device.

Background Art

[0002] In the current market, there are transmitter devices (source devices) that cannot decode the HF-VSDB (HDMI Forum Vendor Specific Data Block) newly defined in the EDID (Extended Display Identification Data) by HDMI (High-Definition Multimedia Interface) 2.0. Therefore, the TV receiver, which is a receiving device (sink device), has a specification that the user manually switches between the EDID for "transmitter devices before HDMI 1.4" and the EDID for "transmitter devices compatible with HDMI 2.0". Here, it should be noted that HDMI 2.0 includes HDMI 2.0a and HDMI 2.0b. Also, HDMI 1.4 includes HDMI 1.4a.

[0003] For example, Patent Document 1 describes HDMI 2.1. In HDMI 2.1, transmission by FRL (Fixed Rate Link) is defined. In this HDMI 2.1, image data is also packetized and transmitted. Before transmitting the image data and audio data, operations such as FRL link training are performed, and the transmission rate (clock rate) is set according to the capability of the transmission path between the transmitter device and the receiving device, including the HDMI cable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] With the currently used 256-byte EDID, it is impossible to combine (merge) the EDID for "transmitter devices compatible with HDMI 2.0" and the EDID for "transmitter devices compatible with HDMI 2.1" into one EDID data. Therefore, it is necessary to be able to switch and use the EDID for "transmitter devices before HDMI 1.4", the EDID for "transmitter devices compatible with HDMI 2.0", and the EDID for "transmitter devices compatible with HDMI 2.1".

[0006] In such a situation, content protection is performed by HDCP (High-bandwidth Digital Content Protection) 2.2 for both HDMI 2.0-compatible transmitter devices and HDMI 2.1-compatible transmitter devices. Therefore, even if the operations performed by HDCP 2.2 are monitored, it is not possible to establish a determination condition for selecting between the EDID for "transmitter devices compatible with HDMI 2.0" and the EDID for "transmitter devices compatible with HDMI 2.1".

[0007] As described above, in HDMI 2.1, an operation called FRL link training is performed. When performing this FRL link training, communication between the transmitter device and the receiver device is carried out via the DDC (Display Data Channel) line. Therefore, if the communication on the DDC line is monitored, it is possible to detect that HDMI transmission between the transmitter device and the receiver device is about to be performed in HDMI 2.1, and this can be used as a condition for selecting the EDID for "transmitter devices compatible with HDMI 2.1".

[0008] The object of this technology is to enable a receiver device to let a transmitter device read appropriate device information (EDID) with less burden on the user.

Means for Solving the Problems

[0009] The concept of this technology is a memory unit that stores first device information and second device information, a communication unit that communicates with an external device, a control unit that determines to cause the external device to read the second device information based on reception of a rewrite signal for the first device information from the external device. The receiving device is provided.

[0010] The receiving device of the present technology may be, for example, a display device. Further, the receiving device of the present technology includes a memory unit that stores the first device information and the second device information, and a communication unit that communicates with an external device. For example, the first device information may be information included in a Status and Control Data Channel Structure (SCDC). In this case, for example, the first device information may be an FRL_Rate that is information regarding a link rate selected by the external device. Also, for example, the communication unit may communicate with the external device through a digital interface cable. In this case, for example, the digital interface cable may be a High-Definition Multimedia Interface (HDMI) cable.

[0011] The control unit determines to cause the external device to read the second device information based on reception of a rewrite signal for the first device information from the external device. For example, the rewrite signal may be determined corresponding to the second device information. In this case, for example, the rewrite signal may be a Max_FRL_Rate that is information regarding a link rate supported by the device described in the second device information.

[0012] Thus, in the present technology, it is determined to cause the external device to read the second device information based on reception of a rewrite signal for the first device information from the external device. Therefore, it becomes possible to automatically cause the external device (transmitting device) to read appropriate device information (EDID) from the receiving device (receiving apparatus), and the usability of the user can be improved.

[0013] Note that the rewrite signal may be transmitted according to the value of FLT_ready, which is information indicating the preparation status of the link training process described in the first device information. Also, in the present technology, for example, the memory unit may further store the third device information, and the control unit may determine to cause an external device to read the third device information when the rewrite signal is not received. In this case, for example, the second device information may be information corresponding to High-Definition Multimedia Interface (HDMI) version 2.1, and the third device information may be information corresponding to HDMI version 2.0.

[0014] In this case, the second device information and the third device information may each be Extended Display Identification Data (EDID) including an HDMI Forum Vendor Specific Data Block (HF-VSDB), which is information regarding the functions supported by the device. And in this case, the second device information may be a 512-byte EDID obtained by combining (merging) the EDID for 4K High frame rate (HFR) and the EDID for 8K.

[0015] Further, for example, the memory unit may further store fourth device information, and the control unit may determine to cause the external device to read the fourth device information when the external device does not correspond to the second device information and the third device information. In this case, the control unit may determine that the external device does not correspond to the second device information and the third device information when it does not receive a predetermined signal from the external device. And, in this case, the predetermined signal may be AKE_Init which is a start signal of an authentication process with the external device. Further, for example, the fourth device information may be information corresponding to before version 1.4 of High-Definition Multimedia Interface (HDMI). And, in this case, the fourth device information may be Extended Display Identification Data (EDID) including Vendor Specific Data Block (VSDB) which is information regarding functions supported by the device.

Brief Description of Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be made in the following order. 1. Embodiments 2. Modification Examples

[0018] <1. Embodiments> [Configuration Example of Transmission / Reception System] FIG. 1 shows a configuration example of a transmission / reception system 10 as an embodiment. This transmission / reception system 10 is configured by connecting a source device (transmission device) 100 and a sink device (reception device) 200. The source device 100 is, for example, a game machine, a disc player, a set-top box, a digital camera, a mobile phone, a personal computer, etc. The sink device 200 is, for example, a display device (display apparatus) such as a television receiver, a PC monitor, a projector.

[0019] The source device 100 and the sink device 200 are connected via an HDMI cable 300 which is a digital interface cable. The source device 100 is provided with a receptacle 101 that constitutes a connector, to which a data transmission unit 102 is connected. The sink device 200 is provided with a receptacle 201 that constitutes a connector, to which a data reception unit 202 is connected. Also, one end of the cable 300 is provided with a plug 301 that constitutes a connector, and the other end is provided with a plug 302 that constitutes a connector. The plug 301 at one end of the cable 300 is connected to the receptacle 101 of the source device 100, and the plug 302 at the other end of this cable 300 is connected to the receptacle 201 of the sink device 200.

[0020] The source device 100 has a control unit 103. This control unit 103 controls the entire source device 100. The data transmission unit 102 is compatible with HDMI 1.4 or earlier, HDMI 2.0, or HDMI 2.1. The sink device 200 has a control unit 203. This control unit 203 controls the entire sink device 200. This control unit 203 controls the data reception unit 202 so that the source device 100 reads the EDID corresponding to its HDMI version.

[0021] When the control unit 203 determines that the data transmission unit 102 is compatible with HDMI 2.1, it decides to cause the data transmission unit 102 to read the HDMI 2.1 EDID. In this case, the HDMI 2.1 EDID set in the EDID ROM in the data reception unit 202 is read into the data transmission unit 102.

[0022] Also, when the control unit 203 determines that the data transmission unit 102 is compatible with HDMI 2.0, it decides to cause the data transmission unit 102 to read the HDMI 2.0 EDID. In this case, the HDMI 2.0 EDID set in the EDID ROM in the data reception unit 202 is read into the data transmission unit 102.

[0023] When the data transmission unit 102 is determined to support versions prior to HDMI 1.4, the control unit 203 decides to have the data transmission unit 102 load the EDID for versions prior to HDMI 1.4. In this case, the data transmission unit 102 loads the EDID for versions prior to HDMI 1.4 set in the EDID ROM within the data reception unit 202.

[0024] As shown in Fig. 2(a), in one embodiment, there is a 256-byte EDID "Standard" as the EDID for versions prior to HDMI 1.4, a 256-byte EDID "Enhanced" as the EDID for HDMI 2.0, and further a 256-byte EDID "Enhanced (4K HFR)" and a 256-byte EDID "Enhanced (8K)" as the EDIDs for HDMI 2.1. Here, for example, the EDID "Enhanced" includes device information corresponding to video with a resolution of 4K up to a frame rate of 60 Hz and High Dynamic Range (HDR) video, and the EDID "Enhanced (4K HFR)" and the EDID "Enhanced (8K)" include device information corresponding to High Frame Rate (HFR) video with a resolution of 4K (3840 × 2160) and a frame rate greater than 60 Hz and video with a resolution of 8K (7680 × 4320), respectively. Also, each of the above EDIDs may be referred to as Enhanced-EDID (E-EDID).

[0025] In another embodiment, as shown in Fig. 2(b), it is assumed that a 256-byte EDID "Standard" is used as the EDID for versions prior to HDMI 1.4, a 256-byte EDID "Enhanced" is used as the EDID for HDMI 2.0, and a 512-byte EDID "Enhanced (4K HFR / 8K)" is used as the EDID for HDMI 2.1. This 512-byte EDID "Enhanced (4K HFR / 8K)" is a combination (merge) of the 256-byte EDID "Enhanced (4K HFR)" and the 256-byte EDID "Enhanced (8K)".

[0026] Here, the EDID for HDMI prior to 1.4 includes a Vendor Specific Data Block (VSDB) which is vendor - specific information storing information about the functions supported by the sink device. Also, the EDIDs for HDMI 2.0 and HDMI 2.1 include an HDMI Forum VSDB (HF - VSDB) which is an extended VSDB.

[0027] "Configuration Example of Data Transmission Unit and Data Reception Unit" FIG. 3 shows a configuration example of a data transmission unit (HDMI transmission unit) 102 of the source device 100 and a data reception unit (HDMI reception unit) 202 of the sink device 200 in the transmission - reception system 10 of FIG. 1.

[0028] In the valid image interval (hereinafter, also appropriately referred to as the active video interval), which is the interval from one vertical synchronization signal to the next vertical synchronization signal excluding the horizontal blanking interval and the vertical blanking interval, the data transmission unit 102 transmits, in one direction, differential signals corresponding to pixel data of an uncompressed image for one screen to the data reception unit 202 through a plurality of channels. Also, in the horizontal blanking interval or the vertical blanking interval, the data transmission unit 102 transmits, in one direction, differential signals corresponding to at least audio data, control data, and other auxiliary data associated with the image to the data reception unit 202 through a plurality of channels.

[0029] That is, the data transmission unit 102 has an HDMI Transmitter 121. The HDMI Transmitter 121, for example, converts uncompressed pixel data of an image into corresponding differential signals and serially transmits them in one direction to the data reception unit 202 connected via the HDMI cable 300 through three TMDS channels #0, #1, #2 which are a plurality of channels.

[0030] Also, the HDMI Transmitter 121 converts audio data associated with the uncompressed image, as well as necessary control data and other auxiliary data, into corresponding differential signals and serially transmits them in one direction to the data reception unit 202 connected via the HDMI cable 300 through the three TMDS channels #0, #1, #2.

[0031] Furthermore, the HDMI transmitter 121 transmits a pixel clock synchronized with the pixel data transmitted on the three TMDS channels #0, #1, and #2 to the data receiver 202 connected via the HDMI cable 300 on the TMDS clock channel. Here, on one TMDS channel #i (i = 0, 1, 2), 10-bit pixel data is transmitted during one clock of the pixel clock.

[0032] Here, the TMDS coding is 8-bit / 10-bit conversion coding that converts 8-bit data into 10-bit data, and it is coding that maintains DC balance while suppressing adverse effects such as unnecessary radiation by reducing transition points from comparison with previous data. Therefore, since the run length of the coding cannot be guaranteed theoretically, DC coupling and separate transmission of the clock are essential.

[0033] The data receiver 202 receives differential signals corresponding to pixel data transmitted unidirectionally from the data transmitter 102 on a plurality of channels in the active video section, and also receives differential signals corresponding to audio data and control data transmitted unidirectionally from the data transmitter 102 on a plurality of channels in the horizontal blanking section or the vertical blanking section.

[0034] That is, the data receiver 202 has an HDMI Receiver 221. The HDMI Receiver 221 receives differential signals corresponding to pixel data transmitted unidirectionally from the data transmitter 102 connected via the HDMI cable 300 on the TMDS channels #0, #1, and #2, and differential signals corresponding to audio data and control data, in synchronization with the pixel clock transmitted from the same data transmitter 102 on the TMDS clock channel.

[0035] In the above description, an example was shown in which image data, audio data, and control data are transmitted over TMDS channels #0, #1, and #2, and pixel clock is transmitted over the TMDS clock channel. This is compatible with HDMI 1.4 and earlier and HDMI 2.0. In the case of HDMI 2.1, transmission is performed using FRL lanes (FRL Lane) #0, #1, #2, and #3. In this case, the TMDS clock channel in FIG. 3 becomes FRL lane #3.

[0036] In this case, data transmission is performed using fixed-rate link (FRL) packets using 3 lanes from #0 to #2 or 4 lanes from #0 to #3. Here, the FRL character (FRL Character) coding is 16-bit / 18-bit conversion coding that converts 16-bit data into 18-bit data, is coding that maintains DC balance, and is coding that enables clock extraction.

[0037] FIG. 4 shows an example of the link rate and the number of lanes corresponding to each link. At link rates identified by "1" (binary 0001) and "2" (binary 0010), 3 lanes out of 4 lanes from #0 to #3, i.e., #0 to #2, are utilized. In this case, lane #3 becomes an inactive lane. Note that the active lane means the lane that transmits data. Also, at link rates identified by "3" (binary 0011), "4" (binary 0100), "5" (binary 0101), and "6" (binary 0110), all 4 lanes from #0 to #3 are utilized.

[0038] In the illustrated example, at the link rate identified by "1" (binary 0001), the bit rate per lane is 3 Gbps. Also, at the link rates identified by "2" (binary 0010) and "3" (binary 0011), the bit rate per lane is 6 Gbps. Also, at the link rate identified by "4" (binary 0100), the bit rate per lane is 8 Gbps. Also, at the link rate identified by "5" (binary 0101), the bit rate per lane is 10 Gbps. Further, at the link rate identified by "6" (binary 0110), the bit rate per lane is 12 Gbps.

[0039] Returning to FIG. 3, the transmission channel of the HDMI system composed of the data transmission unit 102 and the data reception unit 202 also has a transmission channel called DDC (Display Data Channel). This DDC consists of two signal lines (not shown) included in the HDMI cable 300 and performs IIC (Inter-Integrated Circuit) communication between the data transmission unit 102 and the data reception unit 202.

[0040] That is, the data transmission unit 102 has an IIC master block (IIC Master Block) 122. Also, the data reception unit 202 has a memory unit 222. The memory unit 222 includes an EDID ROM (Extended Display Identification Data ROM) 231, an SCDC (Status and Control Data Channel) register unit 232, and an HDCP (High-bandwidth Digital Content Protection) register unit 233.

[0041] The EDID ROM 231 is set with EDID, which is information about the configuration and possible capabilities of the sink device 200, and is read by the IIC master block 122 on the source device 100 side through DDC. Thereby, the source device 100 recognizes the configuration and possible capabilities of the sink device 200. Note that the EDID ROM 231 is realized by a rewritable memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a flash memory, but it may also be a RAM (Random access memory), or can be realized by any other storage medium.

[0042] In this embodiment, when it is determined that the data transmission unit 102 corresponds to HDMI 2.1, HDMI 2.0, and prior to HDMI 1.4 respectively, the EDID for HDMI 2.1, the EDID for HDMI 2.0, and the EDID for prior to HDMI 1.4 are respectively set in the EDID ROM 231, and the set EDID is made to be read by the source device 100 side.

[0043] SCDC (Status and Control Data Channel) corresponds to a point-to-point communication protocol through which the source device 100 and the sink device 200 exchange data. Note that this SCDC is defined after HDMI 2.0. The SCDC register section 232 consists of a register group that stores SCDCS (SCDC Structure).

[0044] The source device 100 (data transmission unit 102) can read and write the data of SCDCS stored in the SCDC register section 232 by the IIC master block 122 through DDC. The data of SCDCS includes data related to the current link state and data for controlling the operation of the source device.

[0045] HDCP (High-bandwidth Digital Content Protection) is an encryption technology that prevents copyrighted video content from being illegally copied while being transmitted to a display device. The HDCP register section 233 consists of a group of registers that store data related to HDCP. The data related to HDCP includes an encryption key for encrypting image data and the like.

[0046] The source device 100 (data transmission unit 102) can read and write data related to HDCP stored in the HDCP register section 233 through DDC by the IIC master block 122.

[0047] Also, although not shown in the figure, the HDMI cable 300 includes a CEC (Consumer Electronics Control) line, an HPD (Hot Plug Detect) line, a reserved line, a power line, and the like. The CEC line is used for bidirectional communication of control data between the source device 100 and the sink device 200. The HPD line is used for the source device 100 to detect the connection of the sink device 200 and the like.

[0048] "EDID Automatic Switching Control Process" With reference to the flowchart of FIG. 5, an example of the procedure of the EDID automatic switching control process in the control unit 203 of the sink device 200 will be described.

[0049] In step ST1, the control unit 203 sets the EDID (Enhanced (4K HFR / 8K)) for HDMI 2.1 in the EDID ROM 231 and causes the source device 100 to read this EDID. In this case, the control unit 203 makes the source device 100 read the EDID for HDMI 2.1 set in the EDID ROM 231 by setting a non-shown HPD (Hot Plug Detect) line to a high level.

[0050] Figure 6 schematically shows the EDID for HDMI 2.1. This EDID for HDMI 2.1 includes data of "Max_FRL_Rate". The EDID includes HF-VSDB (HDMI Forum Vendor Specific Data Block). The data of "Max_FRL_Rate" is the data within HF-VSDB. This data of "Max_FRL_Rate" is a data item that specifies the maximum link rate that the sink device 200 can support. This data of "Max_FRL_Rate" is the data of a 4-bit field that specifies the link rate identifier (see Figure 4) of the maximum link rate that the sink device 200 can support.

[0051] For example, when the data of "Max_FRL_Rate" has a value of "5", it indicates that the sink device 200 supports the link rates associated with the link rate identifiers of "1", "2", "3", "4", and "5", and does not support the link rate associated with the link rate identifier of "6".

[0052] Also, the value of "Max_FRL_Rate" may also indicate whether the sink device 200 supports link training. For example, when the multimedia link is HDMI, the value of "Max_FRL_Rate" may be "0". In that case, it indicates that the sink device 200 supports HDMI operation according to HDMI 1.4 or earlier or HDMI 2.0. That is, when the value of "Max_FRL_Rate" is "0", it indicates that the sink device 200 does not support any of the link rates shown in Figure 4.

[0053] Link training is not performed in HDMI 1.4 or earlier or HDMI 2.0. Therefore, the value of "0" for "Max_FRL_Rate" indicates that the sink device 200 does not support link training, and the values of "1" to "6" for "Max_FRL_Rate" indicate that the sink device 200 supports link training.

[0054] Returning to FIG. 5, in step ST2, the control unit 203 sets "FLT_ready" included in the SCDC data existing in the SCDC register unit 232 to "1".

[0055] FIG. 7 schematically shows the SCDC data stored in the SCDC register unit 232. The SCDC data includes three categories of data items: update flags, configuration parameters, and status flags. The status flags are values representing the current status of the sink device 200.

[0056] The update flags are values (such as 1-bit binary values) associated with the commands of the source device 100. When the source device 100 supports HDMI 2.1, a source link training circuit (not shown) polls the update flags periodically, for example, every 2 milliseconds.

[0057] When one of the update flags is polled by the source link training circuit and has a value of, for example, "1", the source link training circuit executes the command associated with that update flag. In this way, the update flags provide a way to control the link training circuit of the source device 100.

[0058] The status flags include "FLT_ready". A link training control circuit (not shown) of the sink device 200 writes "1" to "FLT_ready" as described above to indicate to the source device 100 that the sink device 200 is ready to start the link training process.

[0059] Configuration parameters are the current data transmission parameters of the HDMI link. The configuration parameters include "FRL_Rate". "FRL_Rate" is the link rate identifier of the current link rate. For example, when using the example of link rates and link rate identifiers shown in FIG. 4, "FRL_Rate" is data in a 4-bit field and stores the Link Rate Identifier (Binary) of the link rate at which the HDMI link is currently operating.

[0060] In the source device 100 compatible with HDMI 2.1, the source link training circuit reads, via DDC, the HDMI 2.1 - specific EDID (see FIG. 6) set in the EDID ROM as described above. In particular, the source link training circuit reads "Max_FRL_Rate" and determines whether the sink device 200 supports link training.

[0061] When the sink device 200 is compatible with HDMI 1.4 or earlier or HDMI 2.0, the sink device 200 does not support link training. In that case, the value of "Max_FRL_Rate" is "0". In this embodiment, since the sink device 200 is compatible with HDMI 2.1 and the source link training circuit reads the HDMI 2.1 - specific EDID (see FIG. 6), the value of "Max_FRL_Rate" is a value other than "0".

[0062] When the value of "Max_FRL_Rate" is other than "0", the source link training circuit of the source device 100 and the link training control circuit of the sink device 200 perform several actions to prepare the HDMI link for link training processing. The link training control circuit writes a value of 1 to "FLT_ready", indicating that the sink device 200 is ready to start link training processing.

[0063] The source link training circuit reads "FLT_ready" periodically, for example, every 2 milliseconds. When the source link training circuit reads "1" as the value of "FLT_ready", the source link training circuit selects a link rate and writes the identifier of the selected link rate to the register of "FRL_Rate". The source link training circuit selects a link rate that is less than or equal to the value of the maximum link rate specified by "Max_FRL_Rate" and is fast enough to support the transmission of content.

[0064] Returning to Figure 5, in step ST3, the control unit 203 determines whether there has been a rewrite of the register of "FRL_Rate", that is, whether the identifier of the link rate has been written to the register of "FRL_Rate". When it is determined that the identifier of the link rate has been written to the register of "FRL_Rate", since this writing is done when the source device 100 supports link training as described above, the control unit 203 decides to cause the source device 100 to read the EDID for HDMI 2.1, and in step ST4, the EDID for HDMI 2.1 remains held in the EDID ROM 231.

[0065] Note that in this case, the EDID for HDMI 2.1 has already been read into the source device 100 (see the description of step ST1). Therefore, at this point, it is not necessary to cause the source device 100 to read the EDID for HDMI 2.1 held in the EDID ROM 231, but it may be read again.

[0066] Also, when it is determined in step ST3 that the identifier of the link rate has not been written to the register of "FRL_Rate", the control unit 203 proceeds to the process of step ST5. As described above, the reading of "FLT_ready" is performed periodically, for example, every 2 milliseconds. Therefore, this determination is made, for example, after at least the time interval of the reading of "FLT_ready" has elapsed since the value of 1 was written to "FLT_ready".

[0067] In step ST5, the control unit 203 determines whether there is a write of "AKE_Init". The image data transmitted from the source device 100 to the sink device 200 via the HDMI cable 300 is encrypted by HDCP (High-bandwidth Digital Content Protection). HDMI 2.0 and HDMI 2.1 adopt HDCP 2.2.

[0068] The source device 100 performs, via DDC, an authentication process with the sink device 200 to determine whether the sink device 200 has a regular HDCP processing function. In HDCP 2.2, an AKE (Authentication and Key Exchange) process for performing an encryption key exchange as the first step of the authentication protocol is implemented. "AKE_Init" is an authentication activation message transmitted from the source device (HDCP transmitter) 100 to the sink device (HDCP receiver) 200 at the beginning of this AKE process.

[0069] The sink device 200 receives "AKE_Init" sent from the source device 100 and writes it to the corresponding address in the HDCP register unit 233. FIG. 8 schematically shows the HDCP data stored in the HDCP register unit 233. The HDCP data includes the data of "AKE_Init".

[0070] FIG. 9(a) shows a structural example (Syntax) of "AKE_Init", and FIG. 9(b) shows the content (Semantics) of the main information in the structural example. The 1-byte field of "msg_id (=2)" is a message identifier indicating that it is "AKE_Init". The 8-byte field of "rTX [63.,0]" is a pseudo-random value. The 3-byte field of "TxCaps" is a fixed value (0x02 0x00 0x00) including version information.

[0071] Returning to FIG. 5, when it is determined in step ST5 that there is a write of "AKE_Init", the write of "AKE_Init" is performed when the source device 100 adopts HDCP2.2 as described above. Since HDMI2.0 adopts HDCP2.2, the control unit 203 determines to let the source device 100 read the EDID for HDMI2.0, and in step ST6, rewrites the EDID held in the EDID ROM 231 to the EDID (Enhanced) for HDMI2.0. After this rewrite, the control unit 203 makes the HPD line high level to let the source device 100 read the EDID for HDMI2.0 set in the EDID ROM 231.

[0072] Also, when it is determined in step ST5 that there is no write of "AKE_Init", the control unit 203 determines to let the source device 100 read the EDID (Standard) for before HDMI1.4, and in step ST7, rewrites the EDID held in the EDID ROM 231 to the EDID for before HDMI1.4. After this rewrite, the control unit 203 makes the HPD line high level to let the source device 100 read the EDID for before HDMI1.4 set in the EDID ROM 231. This determination is made after a predetermined time or more, for example, several hundred milliseconds or more, has elapsed since a value of 1 was written to "FLT_ready".

[0073] As described above, in the transmission / reception system 10 shown in FIG. 1, the sink device 200 determines whether the source device 100 corresponds to HDMI2.1, HDMI2.0, or before HDMI1.4, sets the EDID of the corresponding version in the EDID ROM 231, and lets the source device 100 read it. Therefore, the user operation of setting the EDID of the corresponding version for the source device 100 in the EDID ROM 231 in the sink device 200 becomes unnecessary, and the usability of the user can be improved.

[0074] <2. Modified Example> In the above-described embodiment, the sink device 200 is shown handling a 256-byte EDID "Standard" as the EDID for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" as the EDID for HDMI 2.0, and a 512-byte EDID "Enhanced (4K HFR / 8K)" as the EDID for HDMI 2.1, as shown in FIG. 2(b).

[0075] However, an example where the sink device 200 handles a 256-byte EDID "Standard" as the EDID for HDMI 1.4 and earlier, a 256-byte EDID "Enhanced" as the EDID for HDMI 2.0, a 256-byte EDID "Enhanced (4K HFR)" as the EDID for HDMI 2.1, and a 256-byte EDID "Enhanced (8K)" as the EDID for HDMI 2.1, as shown in FIG. 2(a), can also be considered in the same way.

[0076] The flowchart of FIG. 10 shows an example of the procedure of the EDID automatic switching control process in the control unit 203 of the sink device 200 in that case.

[0077] In step ST11, the control unit 203 sets the EDID for HDMI 2.1 (4K HFR) in the EDID ROM 231 and causes the source device 100 to read this EDID. In this case, the control unit 203 makes the source device 100 read the EDID for HDMI 2.1 (4K HFR) set in the EDID ROM 231 by setting a non-illustrated HPD (Hot Plug Detect) line to a high level. This EDID for HDMI 2.1 (4K HFR) also includes the data of "Max_FRL_Rate" (see FIG. 6).

[0078] Next, in step ST12, the control unit 203 sets "FLT_ready" included in the SCDC data existing in the SCDC register unit 232 to "1". The source link training circuit of the source device 100 reads "FLT_ready" periodically, for example, every 2 milliseconds. When the source link training circuit reads "1" as the value of "FLT_ready", the source link training circuit selects a link rate and writes the identifier of the selected link rate into the register of "FRL_Rate".

[0079] Next, in step ST13, the control unit 203 determines whether there has been a rewrite of the register of "FRL_Rate", that is, whether the identifier of the link rate has been written into the register of "FRL_Rate".

[0080] When it is determined that the identifier of the link rate has been written into the register of "FRL_Rate", since this writing is done when the source device 100 supports link training for HDMI 2.1, in step ST14, the control unit 203 displays on a display unit (not shown) a UI (User Interface) screen for allowing the user to select either the EDID for HDMI 2.1 (4K HFR) or the EDID for HDMI 2.1 (8K). FIG. 11 shows an example of the UI screen. The user selects either "4K HFR" or "8K" with reference to this UI screen, for example. The illustrated example shows a state where the EDID for HDMI 2.1 (4K HFR) is selected.

[0081] Next, in step ST15, the control unit 203 determines whether the selection is "4K HFR" or "8K". When it is determined that the selection is "4K HFR", the control unit 203 decides to have the source device 100 read the EDID for HDMI 2.1 (4K HFR), and in step ST16, the EDID for HDMI 2.1 (4K HFR) remains held in the EDID ROM 231.

[0082] In this case, the EDID for HDMI 2.1 (4K HFR) has already been read into the source device 100 (see the description of step ST11). Therefore, at this point, it is not necessary to have the source device 100 read the EDID for HDMI 2.1 (4K HFR) held in the EDID ROM 231, but it may be read again.

[0083] Also, when it is determined in step ST15 that the selection is "8K", the control unit 203 decides to have the source device 100 read the EDID for HDMI 2.1 (8K). In step ST17, the EDID held in the EDID ROM 231 is rewritten to the EDID for HDMI 2.1 (8K). After this rewrite, the control unit 203 makes the HPD line high level to have the source device 100 read the EDID for HDMI 2.1 (8K) set in the EDID ROM 231.

[0084] Also, when it is determined in step ST13 that there is no writing of the link rate identifier to the register of "FRL_Rate", the control unit 203 proceeds to the process of step ST18. As described above, the reading of "FLT_ready" is performed periodically, for example, every 2 milliseconds. Therefore, this determination is made, for example, after at least the time interval of the reading of "FLT_ready" has elapsed since a value of 1 was written to "FLT_ready".

[0085] In step ST18, the control unit 203 determines whether there is a writing of "AKE_Init". The image data transmitted from the source device 100 to the sink device 200 via the HDMI cable 300 is encrypted by HDCP (High-bandwidth Digital Content Protection). HDMI 2.0 and HDMI 2.1 adopt HDCP 2.2.

[0086] The source device 100 performs an authentication process with the sink device 200 via DDC to determine whether the sink device 200 has a normal HDCP processing function. In HDCP 2.2, an AKE (Authentication and Key Exchange) process for exchanging encryption keys is implemented as the first step of the authentication protocol. "AKE_Init" is an authentication startup message that is first sent from the source device (HDCP transmitter) 100 to the sink device (HDCP receiver) 200 at the beginning of this AKE process.

[0087] When it is determined in step ST18 that there is a write of "AKE_Init", as described above, the write of "AKE_Init" is performed when the source device 100 adopts HDCP 2.2. Since HDMI 2.0 adopts HDCP 2.2, the control unit 203 determines to let the source device 100 read the EDID for HDMI 2.0.

[0088] Then, in step ST19, the control unit 203 rewrites the EDID held in the EDID ROM 231 to the EDID for HDMI 2.0. After this rewrite, the control unit 203 makes the HPD line high level to let the source device 100 read the EDID for HDMI 2.0 set in the EDID ROM 231.

[0089] Also, when it is determined in step ST18 that there is no write of "AKE_Init", the control unit 203 determines to let the source device 100 read the EDID for before HDMI 1.4. This determination is made after a predetermined time or more, for example, a time of several hundred milliseconds or more has elapsed since a value of 1 is written to "FLT_ready".

[0090] Then, in step ST20, the control unit 203 rewrites the EDID held in the EDID ROM 231 to the EDID for before HDMI 1.4. After this rewrite, the control unit 203 sets the HPD line to a high level to cause the source device 100 to read the EDID for before HDMI 1.4 set in the EDID ROM 231.

[0091] In the EDID automatic switching control process shown in the flowchart of FIG. 10, in step ST11, an example is given where the EDID for HDMI 2.1 (4K HFR) is set in the EDID ROM 231 and this EDID is read by the source device 100. However, in this step ST11, it is also conceivable to configure the EDID ROM 231 to set the EDID for HDMI 2.1 (8K) and read this EDID by the source device 100.

[0092] Also, in the above-described embodiment, an example where the interface (multimedia link) is HDMI is shown. This technology can be similarly applied to other interfaces that handle the same EDID. Examples of other interfaces include, for example, the DP (Display Port) interface, MHL (Mobile High-definition Link), and the like. Also, in the above embodiment, examples of HDMI 2.1, HDMI 2.0, and before HDMI 1.4 are shown, but this technology is not limited to such examples and may be applied to future versions of HDMI. Similarly, in the above embodiment, the explanation was made using HDCP 2.2, but this technology may be implemented using an HDCP version before HDCP 2.2 or an HDCP version after HDCP 2.2.

[0093] Also, in the above-described embodiment, in step ST1 or step ST11, the EDID for HDMI 2.1 was stored first, but the EDID for before HDMI 1.4 or the EDID for HDMI 2.0 may be stored first and switched to the EDID for HDMI 2.1 in response to the writing of "FRL_Rate".

[0094] In addition, while the preferred embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field of the present disclosure can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and these are also naturally understood to belong to the technical scope of the present disclosure.

[0095] Also, the effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the technology according to the present disclosure can exhibit other effects that are obvious to those skilled in the art from the description of this specification, together with or instead of the above effects.

[0096] Note that the present technology can also be configured as follows. (1) A memory unit that stores first device information and second device information, A communication unit that communicates with an external device, A control unit that determines to cause the external device to read the second device information based on reception of a rewrite signal to the first device information from the external device. A receiving device. (2) The memory unit further stores third device information, The control unit determines to cause the external device to read the third device information when the rewrite signal is not received. The receiving device according to (1) above. (3) The second device information is information corresponding to version 2.1 of High-Definition Multimedia Interface (HDMI), and the third device information is information corresponding to version 2.0 of HDMI. The receiving device according to (2) above. (4) The second device information and the third device information are each Extended Display Identification Data (EDID) including HDMI Forum Vendor Specific Data Block (HF-VSDB) which is information regarding functions supported by the device. The receiving device according to (3) above. (5) The second device information is a 512-byte EDID combining the EDID for 4K High frame rate (HFR) and the EDID for 8K. The receiving device according to (3) above. (6) The memory unit further stores fourth device information. When the external device does not support the second device information and the third device information, the control unit determines to cause the external device to read the fourth device information. The receiving device according to any one of (2) to (5) above. (7) When the control unit does not receive a predetermined signal from the external device, it determines that the external device does not support the second device information and the third device information. The receiving device according to (6) above. (8) The predetermined signal is AKE_Init which is a start signal for an authentication process with the external device. The receiving device according to (7) above. (9) The fourth device information is information corresponding to versions prior to 1.4 of High-Definition Multimedia Interface (HDMI). The receiving device according to any one of (6) to (8) above. (10) The fourth device information is Extended Display Identification Data (EDID) including Vendor Specific Data Block (VSDB) which is information regarding functions supported by the device. The receiving device according to (9) above. (11) The rewrite signal is determined corresponding to the second device information. The receiving device according to any one of (1) to (10) above. (12) The rewrite signal is information corresponding to Max_FRL_Rate, which is information regarding the link rate supported by the device described in the second device information. The receiving device according to (11) above. (13) The rewrite signal is transmitted according to the value of FLT_ready, which is information indicating the preparation status of the link training process described in the first device information. The receiving device according to any one of (1) to (12) above. (14) The first device information is information included in the Status and Control Data Channel Structure (SCDCS). The receiving device according to any one of (1) to (13) above. (15) The first device information is FRL_Rate, which is information regarding the link rate selected by the external device. The receiving device according to (14) above. (16) The communication unit communicates with the external device through a digital interface cable. The receiving device according to any one of (1) to (15) above. (17) The digital interface cable is a High-Definition Multimedia Interface (HDMI) cable. The receiving device according to (16) above. (18) The receiving device is a display device. The receiving device according to any one of (1) to (17) above. (19) A memory unit for storing the first device information and the second device information, A control method for a receiving device including a communication unit that communicates with an external device, the method comprising: Determining to cause the external device to read the second device information based on reception of the rewrite signal of the first device information from the external device. A control method for a receiving device. (20) Comprising a transmitting device and a receiving device, The receiving device a memory unit that stores first device information and second device information; a communication unit that communicates with the transmitting device; a control unit that determines to cause the transmitting device to read the second device information based on reception of a rewrite signal for the first device information from the transmitting device. A transmission / reception system.

Explanation of Signs

[0097] 10 ··· Transmission / reception system 100 ··· Source device (transmitting device) 101 ··· Receptacle 102 ··· Data transmission unit (HDMI transmission unit) 103 ··· Control unit 121 ··· HDMI transmitter 122 ··· IIC master block 200 ··· Sink device (receiving device) 201 ··· Receptacle 202 ··· Data reception unit (HDMI reception unit) 203 ··· Control unit 221 ··· HDMI receiver 222 ··· Memory unit 231 ··· EDID ROM 232 ··· SCDC register unit 233 ··· HDCP register unit 300 ··· HDMI cable 301, 302 ··· Plug

Claims

1. A memory unit that stores first device information, second device information, and third device information; A communication unit that communicates with an external device; A control unit that determines to cause the external device to read either the second device information or the third device information based on reception of a rewrite signal of the first device information from the external device A receiving device.

2. The second device information is information corresponding to Version 2.1 of High-Definition Multimedia Interface (HDMI), and the third device information is information corresponding to Version 2.0 of HDMI The receiving device according to claim 1.

3. The control unit: Displays a user interface for selecting either the second device information or the third device information based on reception of the rewrite signal of the first device information from the external device, Determines to cause the external device to read either the second device information or the third device information based on a selection on the user interface The receiving device according to claim 1.

4. The second device information is information corresponding to Version 2.1 of High-Definition Multimedia Interface (HDMI), the third device information corresponds to Version 2.1 of HDMI, and is information corresponding to video with a higher resolution than the second device information The receiving device according to claim 3.

5. The first device information is information regarding a link rate selected by the external device The receiving device according to claim 1.

6. The second device information is information corresponding to Version 2.1 of High-Definition Multimedia Interface (HDMI) The receiving device according to claim 5.

7. The receiving device performs two-way communication with the external device The receiving device according to claim 5.

8. The control unit is further configured to cause the external device to read the third device information when the rewrite signal is not received The receiving device according to claim 1.

9. The third device information is information corresponding to Version 2.0 of High-Definition Multimedia Interface (HDMI) The receiving device according to claim 1.

10. The second device information and the third device information are each Extended Display Identification Data (EDID) including a Vendor Specific Data Block (VSDB) which is information regarding functions supported by the device The receiving device according to claim 9

11. The second device information is a 512-byte EDID obtained by combining an EDID for 4K High frame rate (HFR) and an EDID for 8K The receiving device according to claim 9

12. The memory unit further stores fourth device information The control unit is further configured to cause the external device to read the fourth device information when the external device does not support either the second device information or the third device information The receiving device according to claim 8

13. The control unit is further configured to determine that the external device does not support either the second device information or the third device information when the control unit does not receive a predetermined signal from the external device The receiving device according to claim 12

14. The predetermined signal is AKE_Init which is a start signal for an authentication process with the external device The receiving device according to claim 13

15. The fourth device information is information corresponding to Version 1.4 or an earlier version of High-Definition Multimedia Interface (HDMI) The receiving device according to claim 12

16. The fourth device information is Extended Display Identification Data (EDID) including a Vendor Specific Data Block (VSDB) which is information regarding functions supported by the device The receiving device according to claim 15

17. The rewrite signal is determined corresponding to the second device information The receiving device according to claim 1

18. The rewrite signal is information corresponding to Max_FRL_Rate which is information regarding the link rate supported by the device described in the second device information The receiving device according to claim 17

19. The rewrite signal is transmitted according to the value of FLT_ready which is information indicating the readiness of link training described in the first device information The receiving apparatus according to claim 1.

20. The first device information is information included in a Status and Control Data Channel Structure (SCDCS). The receiving apparatus according to claim 1.

21. The first device information is FRL_Rate, which is information regarding a link rate selected by the external device. The receiving apparatus according to claim 20.

22. The first device information is information including at least one flag indicating the current state of the receiving apparatus. The receiving apparatus according to claim 1.

23. The second device information is an EDID of 256 bytes for 4K High frame rate (HFR), and the third device information is an EDID of 256 bytes for 8K. The receiving apparatus according to claim 4.

Images