Radio transmission system

Abstract

To efficiently transmit high-quality video in a wireless transmission system that selects a video signal of an OA tally from among video signals of a plurality of cameras.SOLUTION: A base station side transmission / reception processing unit 43 of a base station side device 4 generates a tally signal flag on the basis of tally signal information generated from script information, and transmits the tally signal flag to a terminal side device 3. When the tally signal flag received from the base station side device 4 indicates an OA tally or the like, the terminal side transmission / reception processing unit 31 of the terminal side device 3 performs transmission processing on a video signal of a camera 2 by using transmission parameters for transmitting a video signal at a transmission rate of 40 Mbps, and transmits the video signal. When the tally signal flag indicates an OA tally or the like, the base station side transmission / reception processing unit 43 performs reception processing on the video signal received from the terminal side device 3 by using the same transmission parameters as the terminal side device 3. A video switcher 42 selects and outputs the video signal of the OA tally from the plurality of video signals after the reception processing.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a wireless transmission system comprising a plurality of cameras, a plurality of terminal side devices that transmit video signals from the cameras, and a base station side device that receives the video signals transmitted from the plurality of terminal side devices and selects one video signal. [Background technology]

[0002] In broadcast program production, the images captured by multiple cameras are switched using a video switcher, etc. In many cases, the video signal output from the camera is sent to the video switcher via a wired line via a camera cable, but wireless cameras are sometimes used for mobility and safety reasons.

[0003] As an example of a wireless transmission system using a wireless camera, a system that transmits high definition video in real time has been disclosed (see, for example, Non-Patent Document 1).

[0004] This non-patent document 1 describes the usefulness of a cable-less production system that utilizes local 5G, as demonstrated through a demonstration experiment in which video signals from multiple cameras are transmitted. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] “Cable-less production system utilizing local 5G”, [online], NHK Enterprises, Inc., [searched June 7, 2023], Internet<URL:https: / / www.nhk-ep.co.jp / wp-content / themes / nep-202107 / assets / data / nep-expo / catalog / local5g.pdf> Summary of the Invention [Problem to be solved by the invention]

[0006] For example, in a wireless transmission system in which multiple terminal devices (each of which is connected to a wireless camera) are connected to one base station device, the total throughput of the transmission rate is divided by the number of cameras, and the resulting transmission rate is assigned to each terminal device (camera). As a result, the quality of the video per terminal device decreases according to the number of terminal devices.

[0007] In this case, for example, the degradation of video quality can be suppressed by adjusting the transmission rate assigned to a specific terminal device in advance. However, when a video switcher installed in the base station device switches video from a specific terminal device to another terminal device, a difference in video quality occurs, which makes the video not suitable for the intent of program production.

[0008] In addition, by reducing the number of cameras, the transmission rate allocated to each terminal device can be increased, which can help prevent degradation of video quality. However, even in this case, the quality of the video may not match the intent of the program production.

[0009] Here, it is expected that by increasing the transmission rate of only the video from the camera selected by the video switcher, that is, the so-called main line video (OA (on-air) tally video), and transmitting the other videos at a lower rate, it will be possible to achieve video switching without any difference in image quality.

[0010] In other words, when using multiple wireless cameras in a wireless transmission system with a preset total throughput, the image quality per camera decreases when the transmission rate is allocated equally. This problem is expected to be solved by controlling the transmission rate.

[0011] Therefore, the present invention has been made to solve the above-mentioned problems, and its object is to provide a wireless transmission system that can efficiently transmit high-quality video when selecting an OA tally video signal from among video signals from multiple cameras. [Means for solving the problem]

[0012] In order to solve the above problem, the wireless transmission system of claim 1 comprises a plurality of cameras, a plurality of terminal side devices corresponding to the plurality of cameras, and a base station side device, and receives video signals from the plurality of cameras by wireless signals via the plurality of terminal side devices, and selects and outputs one of the received plurality of video signals, wherein the base station side device generates a tally signal flag for each of the plurality of cameras, a flag indicating either the OA tally or the NEXT tally, or a flag indicating a non-tally that is neither the OA tally nor the NEXT tally, and transmits the tally signal flag of the camera by wireless signals to the terminal side device corresponding to the camera, receives a video signal of a camera corresponding to the terminal side device from each of the plurality of terminal side devices by wireless signals, and performs a predetermined reception process on the video signal based on the tally signal flag of the corresponding camera, and a base station side transmission / reception processing unit performs the tally signal flag of the corresponding camera by the base station side transmission / reception processing unit. a video switcher that selects a video signal of the camera of the OA tally from among a plurality of video signals that have been subjected to a predetermined reception process, and outputs the video signal, wherein each of the plurality of terminal side devices is provided with a terminal side transmission / reception processing unit that receives the tally signal flag of the camera corresponding to the terminal side device from the base station side device by a wireless signal, performs a predetermined transmission process on the video signal of the corresponding camera based on the tally signal flag, and transmits the video signal that has been subjected to the predetermined transmission process to the base station side device by a wireless signal, wherein the terminal side transmission / reception processing unit performs the predetermined transmission process on the video signal of the corresponding camera using a transmission parameter for setting a transmission rate of the video signal of the corresponding camera to a first transmission rate when the tally signal flag indicates either the OA tally or the NEXT tally, and performs the predetermined transmission process on the video signal of the corresponding camera using a transmission parameter for setting the transmission rate to a second transmission rate that is lower than the first transmission rate when the tally signal flag indicates the non-tally, and the base station side transmission / reception processing unitFor each of the multiple video signals received from the multiple terminal side devices, if the tally signal flag of the camera corresponding to the video signal indicates either the OA tally or the NEXT tally, the predetermined reception process is performed on the video signal using a transmission parameter for setting the transmission rate to the first transmission rate, and if the tally signal flag of the camera corresponding to the video signal indicates the non-tally, the predetermined reception process is performed on the video signal using a transmission parameter for setting the transmission rate to the second transmission rate.

[0013] Furthermore, the wireless transmission system of claim 2 is the wireless transmission system described in claim 1, wherein the base station side device further comprises a script control device that generates tally signal information including information regarding the OA tally camera and information regarding the NEXT tally camera in accordance with script control that chronologically specifies the OA tally camera and the NEXT tally camera among the multiple cameras depending on the video scene, and the base station side transmission / reception processing unit generates the tally signal flag for each of the multiple cameras based on the tally signal information generated by the script control device.

[0014] A wireless transmission system according to claim 3 is the wireless transmission system according to claim 2, wherein the base station side device further comprises a base station side storage unit, and each of the plurality of terminal side devices further comprises a terminal side storage unit, and each of the base station side storage unit and the terminal side storage unit stores, as transmission parameters for setting the first transmission rate, information on a first frame configuration including a first compression rate, a first coding rate, a first modulation multi-level number, and a ratio of the number of uplink slots to the number of downlink slots in a TDD (Time Division Duplex) system, and information on the second transmission rate information on a second compression rate, a second encoding rate, a second modulation multi-level number, and a second frame configuration is stored as transmission parameters for setting the tally signal flag to the OA tally or the NEXT tally, and when the tally signal flag indicates either the OA tally or the NEXT tally, the terminal side transmission / reception processing unit reads out transmission parameters of the information on the first compression rate, the first encoding rate, the first modulation multi-level number, and the first frame configuration from the terminal side storage unit, and performs the predetermined transmission process on the video signal of the corresponding camera using these transmission parameters, and and when the tally signal flag of the camera corresponding to each of the plurality of video signals indicates either the OA tally or the NEXT tally, the base station side transmission / reception processing unit reads out transmission parameters of the first compression rate, the first encoding rate, the first modulation multi-level number, and the information of the second frame configuration from the base station side storage unit and performs the predetermined reception processing on the video signal using these transmission parameters. and when the tally signal flag of the camera corresponding to each of the plurality of video signals indicates either the OA tally or the NEXT tally, the base station side transmission / reception processing unit reads out transmission parameters of the first compression rate, the first encoding rate, the first modulation multi-level number, and the information of the first frame configuration from the base station side storage unit and performs the predetermined reception processing on the video signal using these transmission parameters. Effect of the Invention

[0015] As described above, according to the present invention, in a wireless transmission system in which a video signal of an OA tally is selected from video signals of a plurality of cameras, high-quality video can be efficiently transmitted. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an example of the overall configuration of a wireless transmission system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration example of a terminal side device. [Diagram 3] 13 is a flowchart showing an example of reception processing (an example of receiving a tally signal flag and an example of setting transmission parameters) of the terminal side device. [Figure 4] 13 is a flowchart showing an example of a transmission process (an example of a video signal transmission) of a terminal device. [Diagram 5] FIG. 13 is a diagram showing an example of transmission parameters (compression ratios) stored in a storage unit of a terminal device. [Figure 6] FIG. 2 is a diagram showing an example of transmission parameters (information on coding rate, modulation multi-level number, and frame configuration) stored in a storage unit of a terminal side device. [Figure 7] FIG. 2 is a block diagram showing a configuration example of a base station side device. [Figure 8] 13 is a flowchart showing an example of a transmission process (an example of a tally signal flag transmission and an example of a transmission parameter setting) of a base station side device. [Figure 9] 13 is a flowchart showing an example of a receiving process (an example of receiving a video signal) of a base station side device. [Figure 10] FIG. 11 is a diagram showing an example of script control by a script control device of a base station side device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is based on a wireless transmission system including a plurality of cameras, a plurality of terminal side devices that transmit the video signals of the cameras, and a base station side device that receives the video signals transmitted from the plurality of terminal side devices and selects one of the video signals.

[0018] The present invention is characterized by increasing the transmission rate of the wireless line from the terminal side device corresponding to the camera that is the target of the tally signal to the base station side device by changing the transmission parameters using the tally signal as a trigger.

[0019] As a result, in a wireless transmission system having a total throughput of a predetermined transmission rate, the video signal of the camera that is the target of the tally signal is selected by the base station device, and even if the camera that is the target of the tally signal is changed, it is always transmitted at a high transmission rate, thereby enabling efficient transmission of high-quality video.

[0020] [Wireless Transmission System] First, the overall configuration of a wireless transmission system according to an embodiment of the present invention will be described. Fig. 1 is a schematic diagram showing an example of the overall configuration of a wireless transmission system according to an embodiment of the present invention.

[0021] This wireless transmission system 1 is configured to include a plurality of cameras 2-1, 2-2, 2-3, 2-4, and 2-5, a plurality of terminal side devices 3-1, 3-2, 3-3, 3-4, and 3-5, and a single base station side device 4.

[0022] Each of the cameras 2-1, 2-2, 2-3, 2-4, and 2-5 corresponds to each of the terminal side devices 3-1, 3-2, 3-3, 3-4, and 3-5 on a one-to-one basis. The terminal side devices 3-1, 3-2, 3-3, 3-4, and 3-5 are equipped with terminal side antennas 30-1, 30-2, 30-3, 30-4, and 30-5, respectively, and the base station side device 4 is equipped with a base station side antenna 40.

[0023] The terminal side devices 3-1, 3-2, 3-3, 3-4, and 3-5 and the base station side device 4 are connected by five systems of wireless circuits via the terminal side antennas 30-1, 30-2, 30-3, 30-4, and 30-5 and the base station side antenna 40.

[0024] Hereinafter, cameras 2-1, 2-2, 2-3, 2-4, and 2-5 are collectively referred to as cameras 2, and terminal side devices 3-1, 3-2, 3-3, 3-4, and 3-5 are collectively referred to as terminal side devices 3. Camera 2 may refer to each of cameras 2-1, 2-2, 2-3, 2-4, and 2-5, or may refer to all cameras 2-1, 2-2, 2-3, 2-4, and 2-5. The same applies to terminal side device 3.

[0025] The camera 2 outputs a signal of an image captured by a cameraman operating the camera 2 (image signal) to the corresponding terminal side device 3.

[0026] The terminal side device 3 receives a tally signal flag from the base station side device 4 by wireless signal, and determines whether the corresponding camera 2 is either an OA tally or a NEXT tally, or a non-tally, based on the tally signal flag. If the terminal side device 3 determines that the corresponding camera 2 is either an OA tally or a NEXT tally, it determines a preset first transmission rate and sets transmission parameters corresponding to the first transmission rate. On the other hand, if the terminal side device 3 determines that the corresponding camera 2 is not a tally based on the tally signal flag, it determines a preset second transmission rate (a transmission rate lower than the first transmission rate) and sets transmission parameters corresponding to the second transmission rate.

[0027] The tally signal flag is set by the base station side device 4 for each of the multiple cameras 2. If the camera 2 is the current selection target, a flag indicating OA tally is set in the tally signal flag, and if the camera 2 is the next selection target, a flag indicating NEXT tally is set. If the camera 2 is neither the current selection target nor the next selection target, a flag indicating non-tally is set in the tally signal flag. In other words, the tally signal flag set for each camera 2 indicates whether the camera 2 is an OA tally, a NEXT tally, or a non-tally.

[0028] The terminal side device 3 performs predetermined transmission processing such as compression processing and encoding processing on the video signal input from the corresponding camera 2 using the transmission parameters set according to the tally signal flag, and transmits the video signal after the transmission processing as a wireless signal to the base station side device 4. As a result, five systems of video signals are transmitted from the terminal side device 3 to the base station side device 4.

[0029] The base station side device 4 sets a tally signal flag indicating OA tally, NEXT tally, or non-tally for each camera 2 in accordance with a preset script control, and transmits the tally signal flag of the camera 2 by wireless signal to the terminal side device 3 corresponding to the camera 2. As a result, five systems of tally signal flags are transmitted from the base station side device 4 to the terminal side device 3.

[0030] The base station side device 4 determines for each camera 2 whether the camera 2 is an OA tally or NEXT tally, or a non-tally, based on the tally signal flag. Then, the base station side device 4 determines the first transmission rate or the second transmission rate for each camera 2 by the same process as the terminal side device 3, and sets transmission parameters corresponding to the transmission rate. The transmission parameters for each camera 2 set by the base station side device 4 are the same as the transmission parameters set by the terminal side device 3 corresponding to that camera 2.

[0031] The base station side device 4 receives the respective video signals transmitted from the multiple terminal side devices 3 by wireless signals, and performs predetermined reception processing such as frame construction processing and demodulation processing for each of the multiple video signals using the transmission parameters of the corresponding camera 2. Then, the base station side device 4 selects the video signal of the camera 2 of the OA tally from the multiple video signals after the reception processing, and outputs the selected video signal.

[0032] In this way, the video signals of the OA tally and NEXT tally cameras 2 are transmitted from the terminal side device 3 corresponding to the cameras 2 to the base station side device 4 at the first transmission rate higher than the second transmission rate. Also, the video signals of the non-tally cameras 2 are transmitted from the terminal side device 3 corresponding to the cameras 2 to the base station side device 4 at the second transmission rate lower than the first transmission rate.

[0033] The video signal selected by the base station side device 4 is the video signal of the OA tally camera 2, and by using the tally signal flag, it can always be transmitted at the first transmission rate, enabling efficient and high-quality video transmission in the wireless transmission system 1.

[0034] Furthermore, when camera 2 of the OA tally is switched, camera 2 of the NEXT tally is changed to camera 2 of the OA tally. In this case, the video signal of camera 2 of the NEXT tally is always transmitted at the first transmission rate, like the video signal of camera 2 of the OA tally. Therefore, even at the timing when camera 2 of the NEXT tally is changed to camera 2 of the OA tally, the video signal selected by the base station side device 4 is a signal transmitted at the first transmission rate, so that the transmission rate does not decrease with the switching of camera 2 of the OA tally. In other words, even when camera 2 of the OA tally is switched, continuous high-quality video transmission is possible.

[0035] <Terminal device 3> Next, the terminal side device 3 shown in Fig. 1 will be described in detail. Fig. 2 is a block diagram showing an example of the configuration of the terminal side device 3. This terminal side device 3 includes a terminal side antenna 30, a terminal side transmission / reception processing unit 31, and memory units (terminal side memory units) 34, 35. The terminal side transmission / reception processing unit 31 includes an encoder 32 and a terminal side transceiver 33. Note that Fig. 2 shows only components related to the present invention, and non-related components are omitted.

[0036] The encoder 32 inputs the tally signal flag of the camera 2 corresponding to the terminal side device 3 from the terminal side transceiver 33, determines the transmission rate according to the tally signal flag, and reads out either the compression ratio PA-1 or PA-2 from the memory unit 34 based on the tally signal flag. Either the compression ratio PA-1 or PA-2 read out from the memory unit 34 is set as the compression ratio PA. The tally signal flag is a signal received by the terminal side transceiver 33 from the base station side device 4.

[0037] As a result, the compression rate PA used in the encoder 32 is set (changed) in order to realize a transmission rate according to the tally signal flag.

[0038] The encoder 32 receives a video signal from the corresponding camera 2 , compresses the video signal using a compression rate PA, and outputs the compressed video signal to the terminal-side transceiver 33 .

[0039] The terminal side transceiver 33 receives a modulated radio signal including a tally signal flag of the corresponding camera 2 from the base station side device 4 via the terminal side antenna 30, performs demodulation processing, acquires the tally signal flag, and outputs the tally signal flag to the encoder 32.

[0040] The terminal side transceiver 33 determines the transmission rate according to the tally signal flag, and based on the tally signal flag, reads out one of the coding rates PB-1, PB-2 from the storage unit 35, as well as one of the modulation multi-level numbers PC-1, PC-2, and one of the frame configuration information PD-1, PD-2. Either of the coding rates PB-1, PB-2 read out from the storage unit 35 is set as the coding rate PB, either of the modulation multi-level numbers PC-1, PC-2 is set as the modulation multi-level number PC, and either of the frame configuration information PD-1, PD-2 is set as the frame configuration information PD.

[0041] As a result, the coding rate PB, modulation multi-level number PC, and frame configuration information PD used in the terminal side transceiver 33 are set (changed) in order to realize a transmission rate according to the tally signal flag.

[0042] The frame configuration information PD is information that includes the ratio of the number of uplink slots to the number of downlink slots of TDD (Time Division Duplex) when the terminal side device 3 and the base station side device 4 transmit in TDD (Time Division Duplex) mode.

[0043] The terminal side transceiver 33 inputs the compressed video signal from the encoder 32, performs encoding processing on the compressed video signal using a coding rate PB, performs modulation processing using a modulation multi-level number PC, and performs various processing such as frame composition processing using information PD on the frame composition.

[0044] After performing transmission processing such as compression and encoding, the terminal-side transceiver 33 transmits a modulated radio signal including the video signal after transmission processing to the base station-side device 4 via the terminal-side antenna 30.

[0045] (Example of reception process of terminal device 3) Next, a detailed description will be given of a process (reception process) performed when the terminal side device 3 receives a modulated radio signal including a tally signal flag from the base station side device 4. Fig. 3 is a flowchart showing an example of the reception process (an example of receiving a tally signal flag and an example of setting transmission parameters) of the terminal side device 3.

[0046] The terminal side transceiver 33 receives a modulated radio signal including a tally signal flag from the base station side device 4 via the terminal side antenna 30, performs demodulation processing, and acquires the tally signal flag (step S301). Then, the terminal side transceiver 33 outputs the tally signal flag to the encoder 32.

[0047] The encoder 32 and the terminal-side transceiver 33 determine whether the tally signal flag indicates either an OA tally or a NEXT tally, or whether it indicates a non-tally (step S302).

[0048] When the encoder 32 and the terminal side transceiver 33 determine in step S302 that the tally signal flag indicates either an OA tally or a NEXT tally (step S302: OA tally, NEXT tally), they determine, for example, 40 Mbps as information for determining the transmission rate (step S303). 40 Mbps, which is information for determining the transmission rate, indicates the bit rate when transmitting a video signal from the terminal side device 3 to the base station side device 4.

[0049] The encoder 32 reads out the compression rate PA-1 from the storage unit 34, and sets the compression rate PA-1 as a transmission parameter of the compression rate. The terminal side transceiver 33 also reads out the coding rate PB-1, the modulation multi-level number PC-1, and the frame configuration information PD-1 from the storage unit 35, and sets the coding rate PB-1, the modulation multi-level number PC-1, and the frame configuration information PD-1 as transmission parameters of the coding rate, the modulation multi-level number, and the frame configuration information (step S304).

[0050] As a result, a transmission process is performed on the video signals of the camera 2 of the OA tally and the NEXT tally using the compression rate PA-1, the coding rate PB-1, the modulation multi-level number PC-1, and the frame configuration information PD-1. Then, the modulated radio signal after the transmission process is transmitted to the base station side device 4 at a transmission rate of, for example, 40 Mbps.

[0051] On the other hand, when the encoder 32 and the terminal side transceiver 33 determine in step S302 that the tally signal flag indicates non-tally (step S302: non-tally), they determine, for example, 5 Mbps as information for determining the transmission rate (step S305). 5 Mbps, which is the information for determining the transmission rate, indicates the bit rate when transmitting a video signal from the terminal side device 3 to the base station side device 4.

[0052] The encoder 32 reads out the compression rate PA-2 from the storage unit 34, and sets the compression rate PA-2 as a transmission parameter of the compression rate. The terminal side transceiver 33 also reads out the coding rate PB-2, the modulation multi-level number PC-2, and the frame configuration information PD-2 from the storage unit 35, and sets the coding rate PB-2, the modulation multi-level number PC-2, and the frame configuration information PD-2 as transmission parameters of the coding rate, the modulation multi-level number, and the frame configuration information (step S306).

[0053] As a result, a transmission process is performed on the video signal of the non-tally camera 2 using the compression rate PA-2, the coding rate PB-2, the modulation multi-level number PC-2, and the frame structure information PD-2. Then, the modulated radio signal after the transmission process is transmitted to the base station side device 4 at a transmission rate of, for example, 5 Mbps.

[0054] 5 is a diagram showing an example of transmission parameters (compression ratios) stored in the storage unit 34 of the terminal side device 3. The storage unit 34 stores, for the transmission parameters of compression ratios, a compression ratio PA-1 (for example, for achieving a transmission rate of 40 Mbps) when the tally signal flag is either OA tally or NEXT tally. The storage unit 34 also stores a compression ratio PA-2 (for example, for achieving a transmission rate of 5 Mbps) when the tally signal flag is not tally.

[0055] The encoder 32 reads out the compression ratio PA-1 when the tally signal flag is either the OA tally or the NEXT tally, and reads out the compression ratio PA-2 when the tally signal flag is a non-tally.

[0056] The compression ratio is a ratio that indicates the degree to which the compressed data is reduced compared to the original data when data is compressed. The lower the compression ratio, the greater the amount of compressed data, and the less image degradation caused by compression will be transmitted. For this reason, when the tally signal flag is either the OA tally or the NEXT tally, the compression ratio PA-1 for achieving a transmission rate of 40 Mbps is smaller than the compression ratio PA-2 for achieving a transmission rate of 5 Mbps (PA-1 <PA-2)。

[0057] 6 is a diagram showing an example of transmission parameters (information on coding rate, modulation multi-level number, and frame structure) stored in the storage unit 35 of the terminal side device 3. The storage unit 35 stores, for the transmission parameters of coding rate, modulation multi-level number, and frame structure information, coding rate PB-1 (for example, to realize a transmission rate of 40 Mbps), modulation multi-level number PC-1, and frame structure information PD-1 when the tally signal flag is either OA tally or NEXT tally. The storage unit 35 also stores coding rate PB-2 (for example, to realize a transmission rate of 5 Mbps), modulation multi-level number PC-2, and frame structure information PD-2 when the tally signal flag is non-tally.

[0058] When the tally signal flag is either OA tally or NEXT tally, the terminal side transceiver 33 reads out the coding rate PB-1, the modulation multi-level number PC-1, and the frame configuration information PD-1. When the tally signal flag is non-tally, the terminal side transceiver 33 reads out the coding rate PB-2, the modulation multi-level number PC-2, and the frame configuration information PD-2.

[0059] When the tally signal flag is either an OA tally or a NEXT tally, the coding rate PB-1 and modulation multi-level number PC-1 for achieving a transmission rate of 40 Mbps are greater than the coding rate PB-2 and modulation multi-level number PC-2 for achieving a transmission rate of 5 Mbps (PB-1>PB-2, PC-1>PC-2).

[0060] Furthermore, when the tally signal flag is either an OA tally or a NEXT tally, the ratio indicated by the frame configuration information PD-1 for achieving a transmission rate of 40 Mbps (the ratio of the number of uplink slots to the number of downlink slots) is greater than the ratio indicated by the frame configuration information PD-2 for achieving a transmission rate of 5 Mbps (PD-1>PD-2).

[0061] (Example of transmission process of terminal device 3) Next, a detailed description will be given of a process (transmission process) performed when the terminal side device 3 transmits a modulated radio signal including a video signal to the base station side device 4. Fig. 4 is a flowchart showing an example of a transmission process (video signal transmission example) performed by the terminal side device 3.

[0062] When the tally signal flag indicates either an OA tally or a NEXT tally and the transmission rate is determined to be 40 Mbps, the encoder 32 reads out the compression rate PA-1 from the memory unit 34, and the terminal side transceiver 33 reads out the coding rate PB-1, the modulation multi-level number PC-1, and the frame structure information PD-1 from the memory unit 35.

[0063] On the other hand, if the tally signal flag indicates non-tally and the transmission rate is determined to be 5 Mbps, the encoder 32 reads out the compression rate PA-2 from the memory unit 34, and the terminal side transceiver 33 reads out the coding rate PB-2, the modulation multi-level number PC-2, and the frame structure information PD-2 from the memory unit 35.

[0064] The encoder 32 receives an image signal from the camera 2 corresponding to the terminal side device 3 (step S401).

[0065] Proceeding from step S401, if the tally signal flag indicates either the OA tally or the NEXT tally and the transmission rate is determined to be 40 Mbps, the encoder 32 performs compression processing on the video signal using the compression rate PA-1 (step S402).

[0066] After step S402, the terminal side transceiver 33 performs encoding processing on the video signal compressed by the encoder 32 using the coding rate PB-1, performs modulation processing using the modulation multi-level number PC-1, and performs frame configuration processing, etc. using the frame configuration information PD-1 (step S403), and then proceeds to step S406.

[0067] On the other hand, moving from step S401, if the tally signal flag indicates a non-tally and the encoder 32 determines that the transmission rate is 5 Mbps, it performs compression processing on the video signal using the compression rate PA-2 (step S404).

[0068] After step S404, the terminal side transceiver 33 performs encoding processing on the video signal compressed by the encoder 32 using the coding rate PB-2, performs modulation processing using the modulation multi-level number PC-2, and performs frame configuration processing, etc. using the frame configuration information PD-2 (step S405), and proceeds to step S406.

[0069] The terminal side transceiver 33 proceeds from step S403 or step S405 and transmits a modulated radio signal including a video signal after transmission processing such as compression processing, encoding processing, etc. to the base station side device 4 via the terminal side antenna 30 (step S406).

[0070] In this way, the video signal of camera 2 of OA tally is transmitted from the terminal side device 3 to the base station side device 4 at a transmission rate of 40 Mbps, and the video signal of camera 2 of NEXT tally is transmitted from the terminal side device 3 to the base station side device 4 at a transmission rate of 40 Mbps. Also, the video signal of camera 2 of non-tally is transmitted from the terminal side device 3 to the base station side device 4 at a transmission rate of 5 Mbps.

[0071] In this case, even if the OA tally camera 2 is switched to another camera 2, the video signal of the OA tally camera 2 is continuously transmitted at a transmission rate of 40 Mbps by using the tally signal flag. This enables efficient and high-quality video transmission in the wireless transmission system 1.

[0072] Furthermore, even when camera 2 of the OA tally (e.g., camera 2-1) is switched to another camera 2 (e.g., camera 2-2), i.e., when it is switched to camera 2-2 of the NEXT tally, the video signal of camera 2-2 of the NEXT tally before the switch is transmitted at a transmission rate of 40 Mbps, so the video signal of camera 2-2 at the moment of switching will also be transmitted at a transmission rate of 40 Mbps.

[0073] Therefore, the transmission rate does not decrease when the OA tally switches between cameras 2, making it possible to continuously transmit high-quality video.

[0074] <Base station side device 4> Next, the base station side device 4 shown in Fig. 1 will be described in detail. Fig. 7 is a block diagram showing an example of the configuration of the base station side device 4. This base station side device 4 comprises a base station side antenna 40, a script control device 41, a video switcher 42, a base station side transmission / reception processing unit 43, and memory units (base station side memory units) 46, 47. The base station side transmission / reception processing unit 43 comprises a base station side transceiver 44 and a decoder 45. Note that Fig. 7 shows only components related to the present invention, and non-related components are omitted.

[0075] The script control device 41 generates tally signal information including information for identifying camera 2 of the OA tally and information for identifying camera 2 of the NEXT tally based on script information created in advance, and outputs the tally signal information to a video switcher 42.

[0076] For example, in the production of a program in a studio, the script control device 41 generates tally signal information according to a preset script control that determines which of the multiple cameras 2 should be selected for the OA tally and the NEXT tally. This script control chronologically specifies which of the multiple cameras 2 should be selected for the OA tally and the NEXT tally according to the video scene.

[0077] The video switcher 42 receives the tally signal information from the script control device 41, and specifies the camera 2 of the OA tally based on the tally signal information, and outputs the tally signal information to the base station side transceiver 44.

[0078] The video switcher 42 receives a plurality of video signals from the decoder 45, selects the video signal of the camera 2 of the OA tally from among the plurality of video signals as a video signal of the main line video, and outputs the selected video signal of the main line video.

[0079] In this case, the video signal of the OA tally camera 2 is always continuously transmitted at a transmission rate of 40 Mbps even when the camera 2 of the OA tally is switched to another camera 2 according to the script control of the script control device 41. Therefore, the video signal selected by the video switcher 42 is always a video signal with a transmission rate of 40 Mbps, and as a result, efficient and high-quality video transmission is possible.

[0080] The script control device 41 outputs the tally signal information to the video switcher 42, and also outputs it to the base station transceiver 44 via the video switcher 42. In other words, the script control device 41 does not output the tally signal information directly to the base station transceiver 44. The reason why the video switcher 42 inputs the tally signal information is to accommodate the case where the camera 2 of the OA tally and the camera 2 of the NEXT tally are selected manually in the video switcher 42.

[0081] The base station transceiver 44 receives the tally signal information from the video switcher 42, generates a tally signal flag for each camera 2 based on the tally signal information, and transmits a modulated radio signal including the tally signal flag for the camera 2 to the terminal device 3 corresponding to the camera 2 via the base station antenna 40. As a result, the tally signal flag for each camera 2 (five tally signal flags) is transmitted to the terminal device 3. The base station transceiver 44 also outputs the tally signal flag for each camera 2 to the decoder 45.

[0082] The base station side transceiver 44 determines the transmission rate according to the tally signal flag, and based on the tally signal flag, reads out one of the coding rates PB-1, PB-2 from the storage unit 46, as well as one of the modulation multi-level numbers PC-1, PC-2, and one of the frame configuration information PD-1, PD-2. Either of the coding rates PB-1, PB-2 read out from the storage unit 46 is set as the coding rate PB, either of the modulation multi-level numbers PC-1, PC-2 is set as the modulation multi-level number PC, and either of the frame configuration information PD-1, PD-2 is set as the frame configuration information PD.

[0083] As a result, the coding rate PB, modulation multi-level number PC, and frame configuration information PD used in the base station transceiver 44 are set (changed) in order to realize a transmission rate according to the tally signal flag.

[0084] The base station side transceiver 44 receives modulated radio signals including video signals from each of the multiple terminal side devices 3 via the base station side antenna 40. This allows the video signals (five systems of video signals) for each camera 2 transmitted from the multiple terminal side devices 3 to be received. The base station side transceiver 44 performs frame configuration processing for each of the multiple video signals using frame configuration information PD, demodulation processing using modulation multi-level number PC, and various other processing such as decoding processing using coding rate PB. The base station side transceiver 44 outputs the multiple video signals that have been subjected to frame configuration processing, etc. to the decoder 45.

[0085] The decoder 45 inputs the tally signal flag from the base station transceiver 44, determines the transmission rate according to the tally signal flag, and reads out either the compression ratio PA-1 or PA-2 from the storage unit 47 based on the tally signal flag. Either the compression ratio PA-1 or PA-2 read out from the storage unit 47 is set as the compression ratio PA.

[0086] As a result, the compression rate PA used in the decoder 45 is set (changed) in order to realize a transmission rate according to the tally signal flag.

[0087] The decoder 45 inputs a plurality of video signals that have been subjected to frame configuration processing and the like from the base station side transceiver 44, and performs restoration processing on each of the plurality of video signals using the compression rate PA. Then, the decoder 45 performs reception processing such as frame configuration processing, demodulation processing, decoding processing, and restoration processing, and outputs the plurality of video signals after reception processing to the video switcher 42.

[0088] (Example of transmission process of base station side device 4) Next, a detailed description will be given of a process (transmission process) when the base station side device 4 transmits a radio signal including a tally signal flag to the terminal side device 3. Fig. 8 is a flowchart showing an example of a transmission process (an example of transmitting a tally signal flag and an example of setting transmission parameters) of the base station side device 4.

[0089] The script control device 41 generates tally signal information in accordance with the script control (step S801), and the base station side transceiver 44 generates a tally signal flag for each camera 2 based on the tally signal information (step S802). The processes of steps S803 to S808, which will be described later, are performed for each terminal side device 3.

[0090] The base station transceiver 44 modulates the tally signal flag, and transmits the modulated radio signal including the tally signal flag via the base station antenna 40 (step S803).

[0091] The base station side transceiver 44 and the decoder 45 determine whether the tally signal flag indicates either an OA tally or a NEXT tally, or whether it indicates a non-tally (step S804).

[0092] If the base station transceiver 44 and decoder 45 determine in step S804 that the tally signal flag indicates either an OA tally or a NEXT tally (step S804: OA tally, NEXT tally), they determine, for example, 40 Mbps as the information for determining the transmission rate (step S805).

[0093] The base station side transceiver 44 reads out the coding rate PB-1, the modulation multi-level number PC-1 and the frame structure information PD-1 from the storage unit 46, and sets the coding rate PB-1, the modulation multi-level number PC-1 and the frame structure information PD-1 as the transmission parameters of the coding rate, the modulation multi-level number and the frame structure information. Also, the decoder 45 reads out the compression rate PA-1 from the storage unit 47, and sets the compression rate PA-1 as the transmission parameter of the compression rate (step S806).

[0094] As a result, the OA tally video signal and the NEXT tally video signal transmitted from the terminal side device 3 at a transmission rate of 40 Mbps are received and processed using the compression rate PA-1, the coding rate PB-1, the modulation multi-level number PC-1, and the frame structure information PD-1.

[0095] It is assumed that the storage unit 46 stores the same data as the transmission parameters of the coding rates PB-1, PB-2, etc. stored in the storage unit 35 shown in Fig. 6. It is also assumed that the storage unit 47 stores the same data as the transmission parameters of the compression rates PA-1, PA-2 stored in the storage unit 34 shown in Fig. 5.

[0096] On the other hand, if it is determined in step S804 that the tally signal flag indicates a non-tally (step S804: non-tally), the base station transceiver 44 and decoder 45 determine, for example, 5 Mbps as the information for determining the transmission rate (step S807).

[0097] The base station side transceiver 44 reads out the coding rate PB-2, the modulation multi-level number PC-2 and the frame structure information PD-2 from the storage unit 46, and sets the coding rate PB-2, the modulation multi-level number PC-2 and the frame structure information PD-2 as the transmission parameters of the coding rate, the modulation multi-level number and the frame structure information. Also, the decoder 45 reads out the compression rate PA-2 from the storage unit 47, and sets the compression rate PA-2 as the transmission parameter of the compression rate (step S808).

[0098] As a result, the non-tally video signal transmitted from the terminal side device 3 at a transmission rate of 5 Mbps is subjected to receiving processing using the compression rate PA-2, the coding rate PB-2, the modulation multi-level number PC-2, and the frame structure information PD-2.

[0099] (Example of reception processing of base station side device 4) Next, a detailed description will be given of a process (reception process) performed when the base station side device 4 receives a wireless signal including a video signal from the terminal side device 3. Fig. 9 is a flowchart showing an example of a reception process (video signal reception example) performed by the base station side device 4.

[0100] When the tally signal flag indicates either an OA tally or a NEXT tally and a transmission rate of 40 Mbps is determined, the base station transceiver 44 reads out the coding rate PB-1, the modulation multi-level number PC-1, and the frame structure information PD-1 from the memory unit 46, and the decoder 45 reads out the compression rate PA-1 from the memory unit 47.

[0101] On the other hand, if the tally signal flag indicates non-tally and the transmission rate is determined to be 5 Mbps, the base station side transceiver 44 reads out the coding rate PB-2, the modulation multi-level number PC-2 and the frame configuration information PD-2 from the storage unit 46, and the decoder 45 reads out the compression rate PA-2 from the storage unit 47. The processes of steps S901 to S905 described later are performed for each terminal side device 3, that is, for each video signal of the camera 2 received from the terminal side device 3.

[0102] The base station side transceiver 44 receives a modulated radio signal including a video signal from the terminal side device 3 via the base station side antenna 40 (step S901).

[0103] Moving on from step S901, if the base station transceiver 44 determines that the tally signal flag indicates either an OA tally or a NEXT tally and that the transmission rate is 40 Mbps, it performs frame configuration processing on the video signal using frame configuration information PD-1, demodulation processing using modulation multi-level number PC-1, and decoding processing, etc. using coding rate PB-1 (step S902).

[0104] After step S902, the decoder 45 performs a restoration process using the compression rate PA-1 on the video signal that has been subjected to frame configuration processing and the like by the base station side transceiver 44 (step S903), and proceeds to step S906.

[0105] On the other hand, when the base station side transceiver 44 proceeds from step S901 and determines that the tally signal flag indicates non-tally and the transmission rate is 5 Mbps, it performs frame configuration processing on the video signal using frame configuration information PD-2, performs demodulation processing using modulation multi-level number PC-2, and performs decoding processing, etc. using coding rate PB-2 (step S904).

[0106] After step S904, the decoder 45 performs a restoration process using the compression rate PA-2 on the video signal that has been subjected to frame configuration processing and the like by the base station side transceiver 44 (step S905), and proceeds to step S906.

[0107] The video switcher 42 selects a video signal corresponding to the OA tally included in the tally signal information (video signal of camera 2 of the OA tally) from among the multiple video signals restored by the decoder 45, and outputs the selected video signal (step S906).

[0108] In this way, the video signal of the OA tally camera 2 is transmitted from the terminal side device 3 to the base station side device 4 at a transmission rate of 40 Mbps, and the base station side device 4 performs reception processing using transmission parameters such as frame configuration information PD-1 to realize a transmission rate of 40 Mbps. The same is true for the video signal of the NEXT tally camera 2. Moreover, the video signal of the non-tally camera 2 is transmitted from the terminal side device 3 to the base station side device 4 at a transmission rate of 5 Mbps, and the base station side device 4 performs reception processing using transmission parameters such as frame configuration information PD-2 to realize a transmission rate of 5 Mbps.

[0109] In this case, even if the OA tally camera 2 is switched to another camera 2, the tally signal flag is used to continuously transmit the video signal of the OA tally camera 2 at a transmission rate of 40 Mbps, and reception processing is performed using transmission parameters for achieving the transmission rate of 40 Mbps. This enables efficient and high-quality video transmission in the wireless transmission system 1.

[0110] Furthermore, even when camera 2 of the OA tally (e.g., camera 2-1) is switched to another camera 2 (e.g., camera 2-2), i.e., when it is switched to camera 2-2 of the NEXT tally, the video signal of camera 2-2 of the NEXT tally before the switch is transmitted at a transmission rate of 40 Mbps and reception processing is performed using the transmission parameters to achieve this, so the video signal of camera 2-2 at the moment of switching is also transmitted at a transmission rate of 40 Mbps and reception processing is performed using the transmission parameters to achieve this.

[0111] Therefore, when the OA tally switches between cameras 2, reception processing can be performed without a drop in transmission rate, enabling continuous high-quality video transmission.

[0112] [Operation example] Next, an operation example of the wireless transmission system 1 shown in Fig. 1 will be described. Fig. 10 is a diagram showing an example of script control by the script control device 41 provided in the base station side device 4, and is an operation example assuming switching of five cameras 2-1, 2-2, 2-3, 2-4, and 2-5 corresponding to the wireless transmission system 1 shown in Fig. 1.

[0113] 1, if the total throughput of the overall transmission rate is 100 Mbps, then the transmission rate simply allocated equally is 20 Mbps per unit. In the embodiment of the present invention, as described above, the transmission rate of each of the video signals of the OA tally camera 2 and the NEXT tally camera 2 is 40 Mbps, and the transmission rate of the video signal of the non-tally camera 2 is 5 Mbps.

[0114] In this case, in comparison with main line video, the transmission rate of 40 Mbps in the case of the embodiment of the present invention is about twice as high as the transmission rate of 20 Mbps when the total throughput of 100 Mbps is simply allocated equally. Therefore, the embodiment of the present invention can improve the quality of the video.

[0115] With reference to Fig. 10, the scene numbers of the video are 1, 2, and 3, and time passes in that order. In each of the scene numbers 1, 2, and 3, the status of the camera used, camera 2 of the OA tally, and all cameras, is set. The script control specifies camera 2 of the OA tally and camera 2 of the NEXT tally in chronological order according to the video scene numbers 1, 2, and 3.

[0116] In scene number 1, camera 2-1 is selected as the first camera to be used, and camera 2-1 of the OA tally and camera 2-2 of the NEXT tally to be switched to next are specified. In this case, the video signals of camera 2-1 and camera 2-2 are transmitted at a transmission rate of 40 Mbps, and the video signals of the other non-tally cameras 2-3, 2-4, and 2-5 are transmitted at a transmission rate of 5 Mbps.

[0117] In scene number 1, camera 2-2 is selected as the next camera to be used, and camera 2-2 is specified as the OA tally and camera 2-1 is specified as the NEXT tally. In this case as well, the video signals of camera 2-1 and camera 2-2 are transmitted at a transmission rate of 40 Mbps, and the video signals of the other non-tally cameras 2-3, 2-4, and 2-5 are transmitted at a transmission rate of 5 Mbps.

[0118] Therefore, in scene number 1, when the OA tally is switched from camera 2-1 to camera 2-2, the video signal of the OA tally continues to be transmitted at the same transmission rate of 40 Mbps.

[0119] Next, when scene number 1 is changed to scene number 2, camera 2-1 is selected as the first camera to be used in scene number 2, and camera 2-1 of the OA tally and camera 2-3 of the NEXT tally are specified. In this case, the video signals of camera 2-1 and camera 2-3 are transmitted at a transmission rate of 40 Mbps, and the video signals of the other non-tally cameras 2-2, 2-4, and 2-5 are transmitted at a transmission rate of 5 Mbps.

[0120] Therefore, when the scene transitions from scene number 1 to scene number 2, when the OA tally is switched from camera 2-2 to camera 2-1, the video signal of the OA tally continues to be transmitted at the same transmission rate of 40 Mbps.

[0121] In scene number 2, camera 2-3 is selected as the next camera to be used, and camera 2-3 is designated as the OA tally and camera 2-4 is designated as the NEXT tally. In this case, the video signals of camera 2-3 and camera 2-4 are transmitted at a transmission rate of 40 Mbps, and the video signals of the other non-tally cameras 2-1, 2-2, and 2-5 are transmitted at a transmission rate of 5 Mbps.

[0122] Therefore, in scene number 2, when the OA tally is switched from camera 2-1 to camera 2-3, the video signal of the OA tally continues to be transmitted at the same transmission rate of 40 Mbps.

[0123] Similarly, when the scene moves from scene number 2 to scene number 3 and when the camera 2 of the OA tally is switched in scene number 3, the video signal of the OA tally continues to be transmitted at the same transmission rate of 40 Mbps. In this way, even when the camera 2 of the OA tally is switched, a high-quality video signal can be continuously transmitted.

[0124] As described above, according to the wireless transmission system 1 of the embodiment of the present invention, the terminal side device 3 receives the tally signal flag of the corresponding camera 2 from the base station side device 4. When the encoder 32 of the terminal side device 3 determines that the tally signal flag indicates either the OA tally or the NEXT tally, it reads out the transmission parameters of the compression rate PA-1 for transmitting the video signal at a transmission rate of, for example, 40 Mbps from the storage unit 34. When the terminal side transceiver 33 makes the same determination as above, it reads out the transmission parameters of the coding rate PB-1, the modulation multi-level number PC-1, and the frame structure information PD-1 for transmitting the video signal at the same transmission rate as above from the storage unit 35.

[0125] On the other hand, when the encoder 32 determines that the tally signal flag indicates a non-tally, it reads out the transmission parameters of the compression rate PA-2 for transmitting the video signal at a transmission rate of, for example, 5 Mbps from the storage unit 34. Furthermore, when the terminal-side transceiver 33 makes the same determination as above, it reads out the transmission parameters of the coding rate PB-2, the modulation multi-level number PC-2, and the frame structure information PD-2 for transmitting the video signal at the same transmission rate as above from the storage unit 35.

[0126] Then, the encoder 32 and the terminal-side transceiver 33 perform a predetermined transmission process using these transmission parameters. The terminal-side transceiver 33 transmits the video signal after the transmission process to the base station-side device 4.

[0127] The script control device 41 of the base station side device 4 generates tally signal information based on script information created in advance. The video switcher 42 selects an OA tally video signal from among the multiple video signals input from the decoder 45 based on the tally information signal, and outputs the selected video signal.

[0128] The base station side transceiver 44 generates a tally signal flag for each camera 2 based on the tally signal information, and transmits the tally signal flag to the terminal side device 3.

[0129] When the base station side transceiver 44 judges that the tally signal flag indicates either the OA tally or the NEXT tally, it reads out the transmission parameters of the coding rate PB-1, the modulation multi-level number PC-1, and the frame structure information PD-1 for transmitting the video signal at a transmission rate of, for example, 40 Mbps from the storage unit 46. Also, when the decoder 45 makes the same judgment as above, it reads out the transmission parameters of the compression rate PA-1 for transmitting the video signal at the same transmission rate as above from the storage unit 47.

[0130] On the other hand, when the base station side transceiver 44 determines that the tally signal flag indicates non-tally, it reads out the transmission parameters of the coding rate PB-2, the modulation multi-level number PC-2, and the frame structure information PD-2 for transmitting the video signal at a transmission rate of, for example, 5 Mbps from the storage unit 46. Also, when the decoder 45 makes the same determination as above, it reads out the transmission parameters of the compression rate PA-2 for transmitting the video signal at the same transmission rate as above from the storage unit 47.

[0131] Then, the base station side device 4 receives the video signal from the terminal side device 3, and the base station side transceiver 44 and decoder 45 perform a predetermined receiving processing using these transmission parameters, and output the video signals of the multiple cameras 2 to the video switcher 42.

[0132] In this way, when the tally signal flag indicates either an OA tally or a NEXT tally, the transmission parameters are set to transmit the video signal at a higher transmission rate than when the flag indicates a non-tally. Then, the terminal side device 3 performs a transmission process using the transmission parameters, and the base station side device 4 performs a reception process using the transmission parameters.

[0133] As a result, the video signal of the OA tally camera 2 is always transmitted from the terminal side device 3 to the base station side device 4 at a higher transmission rate than the video signal of the non-tally camera 2. Even if the OA tally camera 2 is switched to another camera 2, the video signal of the OA tally camera 2 after the switch continues to be transmitted at the high transmission rate.

[0134] Then, a video signal with a high transmission rate based on the script control is always selected by the video switcher 42 of the base station side device 4. Therefore, efficient and high-quality video transmission is possible in the wireless transmission system 1.

[0135] Furthermore, when camera 2 is switched from OA tally to NEXT tally, the video signal of camera 2 of the NEXT tally before the switch is also transmitted at a higher transmission rate than the other cameras 2, just like camera 2 of the OA tally. Therefore, the video signal at the moment of switching (video signal of camera 2 after switching) is also transmitted at the same high transmission rate as before the switch.

[0136] In other words, by using two signals, the OA tally indicating the currently selected camera 2 and the NEXT tally indicating the next camera 2 to be selected, the transmission rate of only the video signal of the camera 2 targeted by the OA tally and NEXT tally is increased. This makes it possible to continuously transmit high-quality video without a drop in transmission rate when the OA tally switches to another camera 2.

[0137] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the technical concept thereof.

[0138] For example, in the embodiment, the number of cameras 2 and the number of terminal side devices 3 in the wireless transmission system 1 shown in Fig. 1 are five. The present invention does not limit the number of cameras 2 and the number of terminal side devices 3, and may be two or more.

[0139] In the above embodiment, the compression rate PA, the coding rate PB, the modulation multi-level number PC, and the frame structure information PD are used as transmission parameters for setting the transmission rate. These transmission parameters are merely examples, and some of these transmission parameters may be used, or other transmission parameters may be used in addition to these transmission parameters.

[0140] The transmission parameters for setting the transmission rate can be arbitrarily selected according to the wireless transmission system 1 to which it is applied, and the values ​​thereof can also be arbitrarily set according to the transmission rate.

[0141] In the above embodiment, the tally signal flag of the camera 2 transmitted from the base station side device 4 to the terminal side device 3 is set to ternary data indicating whether the camera 2 is an OA tally, a NEXT tally, or a non-tally. In contrast, the tally signal flag may be set to binary data indicating a tally indicating either an OA tally or a NEXT tally, or a non-tally.

[0142] In addition, a normal computer can be used as the hardware configuration of the terminal side device 3 and the base station side device 4 according to the embodiment of the present invention. The terminal side device 3 and the base station side device 4 are configured by a computer equipped with a CPU, a volatile storage medium such as a RAM, a non-volatile storage medium such as a ROM, an interface, etc.

[0143] The functions of the terminal side transmission / reception processing unit 31 (encoder 32 and terminal side transceiver 33) and memory units 34 and 35 provided in the terminal side device 3 are each realized by causing a CPU to execute a program describing these functions.

[0144] In addition, the functions of the script control device 41, video switcher 42, base station side transmission / reception processing unit 43 (base station side transceiver 44 and decoder 45), and memory units 46 and 47 provided in the base station side device 4 are each realized by having the CPU execute a program that describes these functions.

[0145] These programs are stored in the storage medium and are read and executed by the CPU. These programs can also be distributed by storing them in a storage medium such as a magnetic disk (floppy disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory, and can also be transmitted and received via a network. [Explanation of symbols]

[0146] 1. Wireless transmission system 2 Camera 3. Terminal side equipment 4 Base station side equipment 30 Terminal side antenna 31 Terminal side transmission / reception processing unit 32 Encoder 33 Terminal side transceiver 34,35,46,47 Storage section 40 Base station antenna 41 Script control device 42 Video Switcher 43 Base station side transmission / reception processing unit 44 Base station transmitter / receiver 45 Decoder PA Compression Ratio PB coding rate PC modulation multi-value PD frame configuration information

Claims

1. A wireless transmission system that includes a plurality of cameras, a plurality of terminal side devices corresponding to the plurality of cameras, and a base station side device, receives video signals from the plurality of cameras via the plurality of terminal side devices as wireless signals, and selects and outputs one of the received video signals, The base station side device, Among the plurality of cameras, a currently selected camera is set as an OA tally, and a next selected camera is set as a NEXT tally, generating a tally signal flag for each of the plurality of cameras, the flag indicating either the OA tally or the NEXT tally, or a flag indicating a non-tally that is neither the OA tally nor the NEXT tally, and transmitting the tally signal flag of the camera by a wireless signal to a terminal side device corresponding to the camera; a base station side transmission / reception processing unit that receives a video signal of a camera corresponding to each of the plurality of terminal side devices by a wireless signal, and performs a predetermined reception process on the video signal based on the tally signal flag of the corresponding camera; a video switcher that selects a video signal of a camera of the OA tally from among the plurality of video signals that have been subjected to the predetermined reception processing by the base station side transmission / reception processing unit, and outputs the video signal; Each of the plurality of terminal side devices a terminal side transmission / reception processing unit that receives the tally signal flag of a camera corresponding to the terminal side device from the base station side device by a wireless signal, performs a predetermined transmission process on a video signal of the corresponding camera based on the tally signal flag, and transmits the video signal that has been subjected to the predetermined transmission process to the base station side device by a wireless signal; The terminal side transmission / reception processing unit performing the predetermined transmission process on the video signal of the corresponding camera using a transmission parameter for setting a transmission rate of the video signal of the corresponding camera to a first transmission rate when the tally signal flag indicates either the OA tally or the NEXT tally; performing the predetermined transmission process on the video signal of the corresponding camera using a transmission parameter for setting the transmission rate to a second transmission rate lower than the first transmission rate when the tally signal flag indicates the non-tally; The base station side transmission / reception processing unit performing the predetermined reception process on each of the plurality of video signals received from the plurality of terminal side devices, when the tally signal flag of a camera corresponding to the video signal indicates either the OA tally or the NEXT tally, using a transmission parameter for setting the transmission rate to the first transmission rate; A wireless transmission system characterized in that, when the tally signal flag of a camera corresponding to the video signal indicates the non-tally, the specified receiving processing is performed on the video signal using transmission parameters for setting the transmission rate to the second transmission rate.

2. 2. The wireless transmission system according to claim 1, The base station side device further a script control device that generates tally signal information including information regarding the OA tally camera and information regarding the NEXT tally camera according to a script control that chronologically specifies the OA tally camera and the NEXT tally camera among the plurality of cameras according to a scene of a video; The base station side transmission / reception processing unit a tally signal flag for each of the plurality of cameras based on the tally signal information generated by the script control device;

3. 3. The wireless transmission system according to claim 2, the base station side device further comprises a base station side storage unit, and each of the plurality of terminal side devices further comprises a terminal side storage unit; Each of the base station side storage unit and the terminal side storage unit stores, as transmission parameters for setting the first transmission rate, information on a first frame configuration including a first compression rate, a first coding rate, a first modulation multi-level number, and a ratio of the number of uplink slots to downlink slots in a TDD (Time Division Duplex) system, and, as transmission parameters for setting the second transmission rate, information on a second compression rate, a second coding rate, a second modulation multi-level number, and a second frame configuration, The terminal side transmission / reception processing unit When the tally signal flag indicates either the OA tally or the NEXT tally, transmission parameters of the first compression rate, the first coding rate, the first modulation multi-level number, and the first frame configuration information are read from the terminal side storage unit, and the predetermined transmission process is performed on the video signal of the corresponding camera using these transmission parameters; When the tally signal flag indicates the non-tally, transmission parameters of the second compression rate, the second encoding rate, the second modulation multi-level number, and the second frame configuration are read from the terminal side storage unit, and the predetermined transmission process is performed on the video signal of the corresponding camera using these transmission parameters; The base station side transmission / reception processing unit for each of the plurality of video signals, when the tally signal flag of the camera corresponding to the video signal indicates either the OA tally or the NEXT tally, read out transmission parameters of information of the first compression rate, the first coding rate, the first modulation multi-level number, and the first frame configuration from the base station side storage unit, and perform the predetermined reception process on the video signal using these transmission parameters; A wireless transmission system characterized in that, when the tally signal flag of a camera corresponding to the video signal indicates the non-tally, transmission parameters of the second compression rate, the second encoding rate, the second modulation multi-level number, and information of the second frame structure are read from the base station side memory unit, and the specified receiving processing is performed on the video signal using these transmission parameters.

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