JP4738251B2 - Synchronous automatic adjustment device - Google Patents

Description

  The present invention relates to synchronization adjustment of video signals given from a plurality of cameras, and more particularly to an automatic synchronization adjustment apparatus suitable for a wireless camera system.

  For example, in a television broadcasting station, many cameras (TV cameras) are often used in a relatively narrow place such as a studio. At this time, if a cable is connected to the camera, this is free. It becomes an obstacle to camera operation. Therefore, in recent years, a so-called wireless camera system in which a camera is wirelessly used has been used for business purposes (see, for example, Patent Documents 1 and 2).

  Therefore, in the following, such a wireless camera system will be described. First, in the case of such a commercial camera system, a camera is not usually configured as a single unit, but a CCU (Camera Controll Unit: camera) is installed in the camera body. In general, a control system is configured as a so-called camera system in which a pair of control devices are combined. Therefore, for example, the operation status in a studio in this case is as shown in FIG.

  FIG. 4 shows, for example, a singer on a stage as a subject P in a television broadcasting studio S, and this is processed by, for example, six cameras 1A, 1B, 1C, 1D, 1E, and 1F (hereinafter referred to as 1A to 1F). This is an example of imaging and creating a broadcast program. At this time, each camera 1A to 1F has a pair of CCUs 2A, 2B, 2C, 2D, 2E, and 2F (hereinafter referred to as 2A to 2F). Thus, it is shown that the above-described camera system is configured.

  At this time, as shown in the drawing, an attached antenna is drawn on each camera and CCU, whereby the cameras 1A to 1F and the CCUs 2A to 2F are made wireless, and as a result, so-called wireless cameras are obtained. It can be seen that the system is configured and these cameras 1A to 1F are carried and operated by the cameraman M.

  Therefore, the cameraman M captures the subject P from various angles by the cameras 1A to 1F, and acquires video signals called main line video signals. The main line video signal is subjected to data compression processing in the camera body and wirelessly transmitted to each of the paired CCUs 2A to 2F. Note that the data compression processing at this time is an encoding method such as H.264 or MPEG, but is not limited thereto.

  As a result, the CCUs 2A to 2F decompress the received signals, reproduce the signals as main video signals 110a to 110f of the corresponding cameras, and supply each to the switch 3. Therefore, the switch 3 selects a video signal that is a candidate for an on-air signal (a signal that is actually transmitted from the transmitter) from these main video signals 110a to 110f, that is, the on-air video signal 114, and sends it to the studio sub-adjustment room 4. Output. Accordingly, the operation of the switch 3 at this time is performed from the studio sub-adjustment room 4 which is commonly called a sub.

  At this time, although not shown, the on-air video signal 114 that is the output of the switch 3 is not only output to the studio sub-adjustment room 4, but is also supplied to each of the CCUs 2A to 2F in parallel therewith, From there, it is wirelessly transmitted as a return video signal to each of the corresponding cameras 1A to 1F, and an image is displayed on a VF (video finder) of each camera 1A to 1F. Therefore, each cameraman M can monitor an image based on an on-air video signal in addition to an image captured by the cameraman M, and can perform a camera operation based on this assumption.

  In this case, there is no problem if the main video signals 110a to 110f output from the CCUs 2A to 2F are all in the same phase. However, if the phases are synchronized, the switch 3 When it is switched at, image disturbance occurs although it is a short time until synchronization is again applied. In this case, image disturbance occurs in the on-air video, so that the broadcast quality cannot be maintained.

  Therefore, each of the cameras 1A to 1F uses the above-described return video signal, and will be described in detail later. However, the captured main line video signal is synchronized with the return video signal to cope with the above-described problem. The main line video signals 110a to 110f output from the CCUs 2A to 2F are kept in synchronization with each other, so that image disturbance due to switching does not occur.

  Next, details of the cameras 1A to 1F and CCUs 2A to 2F in FIG. 4 will be described with reference to FIG. At this time, as illustrated, each of the cameras 1A to 1F is represented by the camera 1, and each of the CCUs 2A to 2F is represented by the CCU 2.

  First, the camera 1 has a camera head 9 constituting an optical system and an imaging system. A signal acquired by imaging the subject P is output as a main video signal 100 and supplied to the S / P converter 10. Is done. The main line video signal 100 at this time is compatible with, for example, 1.485 Gbit / s HD-SDI (HDTV SERIAL DIGITAL INTERFACE) format. Therefore, in the S / P converter 10, the main line video signal 100 is converted into parallel video data 101. And is supplied to the active video extraction unit 11.

  At this time, the active video extraction unit 11 removes the vertical blanking period and horizontal blanking period data unnecessary for the display image from the parallel video data 101 and supplies the active video data 102 to the compression unit 12. To do. Here, the active video is a video that is actually displayed. For example, in the case of an HDTV 1080i format signal, the active video is 1920 pixels × 1080 in an image of 2200 pixels × 1125 lines (so-called full image). It becomes an image of a line. HDTV is a so-called high-vision standard, whereas the NTSC standard is called SDTV.

  The compression unit 12 performs a data compression process on the input active video data 102 and outputs the compressed video data 103 to the multiplexing unit 13. The data compression processing at this time is, for example, encoding based on MPEG-2, but is not limited to encoding by compression, and may be encoding by a non-compression method.

  On the other hand, the camera 1 is provided with a microphone 14 so that the voice of the cameraman M can be picked up. The audio signal 104 output from the microphone 14 is input to the S / P converter 15, converted into parallel audio data 105, and supplied to the multiplexer 13.

  Therefore, the multiplexing unit 13 receives the video compression data 103 and the parallel audio data 105, time-division multiplexes them, converts them into multiplexed data 106, and supplies them to the modulation unit 16. The format of the multiplexed data 106 at this time is, for example, TS (transport streamer), and the modulation unit 16 adds a predetermined error correction function to the multiplexed data 106 and puts it on a carrier of a predetermined frequency. By supplying the modulation data 45 to the antenna 40, radio waves are transmitted from the camera 1.

  At this time, the radio channel of the CCU 2 that is paired with the camera 1 is individually assigned to each pair in advance by the directivity of the antenna. Therefore, the radio wave transmitted at this time is received as modulation data 45 by the antenna 41 of the CCU 2 paired with the camera 1, and this is converted into the modulation data 46 and input to the demodulation unit 17, where it is demodulated. The multiplexed data 106 is output to the separating unit 18, the compressed video data 107 and the parallel audio data 111 are separated from the multiplexed data 106, the compressed video data 107 is input to the decompressing unit 19, and the parallel audio data 111 is converted into a P / S converting unit. 22 is input.

  More specifically, first, in the decompression unit 19, the input video compression data 107 is subjected to data decompression processing, and parallel video data 108 is output. Next, this is input to the blanking information adding unit 20 where a horizontal blanking period and a vertical blanking period are added and output as parallel video data 109.

  As a result of this input to the P / S converter 21, the same main line video signal as the original main line video signal 100 output from the camera head 9 of the camera 1, for example, the main line video signal 110a is output from the CCU 2, The main line video signal supplied from the CCU, for example, the main line signals 110b to 110f, is input to the switch 3, and the on-air video signal 114 is selected from them.

  On the other hand, the parallel audio data 111 input to the P / S converter 22 is returned to the original audio signal, that is, the same audio signal 112 as the audio signal 104 picked up by the microphone 14 of the camera 1. Then, this is output from the CCU 2 to the speaker 5 and restored to sound. This is because of an intercom function for connecting the studio sub-adjustment room 4 and the cameraman M with sound together with the microphone 7 and the speaker 8 described later.

  The on-air video signal 114 selected by the switch 3 is taken into the CCU 2 again in order to enable the above-described on-air video to be monitored on the camera side. Then, it is first input to the down converter 23, where it is down-converted from HDTV video to SDTV video, and is supplied to the synchronization unit 24 as a return video signal 115 with reduced resolution. At this time, another reference video signal 116 is input from the reference video signal generator 6 to the synchronization unit 24.

  Therefore, the synchronizing unit 24 synchronizes the input return video signal 115, whereby the return video signal 117 synchronized with the reference video signal 116 is supplied to the synchronization adjustment buffer 26 and temporarily stored therein. However, at this time, the accumulation time information 251 is input from the accumulation time setting unit 25 to the synchronization adjustment buffer 26.

  Therefore, the return video signal 117 is accumulated in the synchronization adjustment buffer 26, and the time delayed here is set in advance by the accumulation time information 251. Thereafter, the return video signal 117 is determined by the accumulation time information 251. The return video signal 118 is output from the synchronization adjustment buffer 26 and input to the S / P converter 27 from the time point.

  Then, the parallel video data 119 converted in parallel from the return video signal 118 is output by the S / P conversion unit 27 and is input to the active video extraction unit 28, where the horizontal blanking period and the vertical blanking period are input. The data of the ranking period is removed, and the active video data 120 is input to the compression unit 29. As a result of the data compression by the compression unit 29, the compressed video data 123 is input to the multiplexing unit 31.

  In addition, the audio signal 121 is supplied to the CCU 2 from the external microphone 7 and input to the S / P converter 30. Accordingly, parallel audio data 122 converted in parallel by the S / P converter 30 is also input to the multiplexing unit 31 together with the video compression data 123 described above. Therefore, the multiplexing unit 31 time-division multiplexes the compressed video data 123 and the parallel audio data 122 and supplies the multiplexed data 124 to the modulation unit 32.

  In the modulation unit 32, a code necessary for giving a predetermined error correction function is added to the input multiplexed data 124, and the modulated data 48 is put on a carrier of a predetermined frequency to be supplied to the antenna 43. , Radio waves are transmitted from the CCU 2.

  Here, the wireless channel of the camera 1 paired with the CCU 2 is assigned to each pair in advance, and at this time, the wireless channel assigned to the transmission from the camera 1 to the CCU 2 is set to a different channel. is there. Therefore, the radio wave transmitted from the CCU 2 at this time is received by the antenna 42 of the camera 1 paired with the CCU 2, and the modulation data 48 becomes the modulation data 47 and is input to the demodulation unit 33 of the camera 1. become.

  In the demodulator 33, the input modulation data 47 is demodulated into multiplexed data 125 and output to the separator 34. In the separation unit 34, the compressed video data 126 is separated from the multiplexed data 125, and this is input to the decompression unit 35. Similarly, the separated parallel audio data 128 is input to the P / S conversion unit 39. .

  At this time, first, the decompression unit 35 performs the data decompression process on the input video compressed data 126 and outputs parallel video data 127, which is input to the blanking information adding unit 36, and the horizontal blanking period and the vertical blanking period. Is added and output as parallel video data 130. Then, this is input to the P / S conversion unit 37 and subjected to serial conversion. As a result, a return video signal 131 is output and supplied to the VF 38 and the camera head 9 of the camera 1.

  Therefore, as described with reference to FIG. 4, the cameraman M can monitor the image based on the on-air video signal by the VF 38 in addition to the image that he / she is capturing, and can operate the camera 1 on the premise of this. . The return video signal is in the SD-SDI (SDTV Serial Digital Interface) format of 270 Mbit / s, for example.

  At this time, the P / S conversion unit 39 converts the parallel audio data 128 input here into serial data, and supplies the serial audio signal 129 to the speaker 8. Therefore, sound can be obtained from the speaker 8. As described above, this is because of the intercom function that connects between the studio sub-adjustment room 4 and the cameraman M.

  Here, the reason why the accumulation time setting unit 25 is provided in the CCU 2 will be described. This is because all the main line video signals 110a to 110f inputted to the switching unit 3 are synchronized, and the on-air video signal selected by the switching unit 3 114 is set so that the phase is the same regardless of which main line video signal 110a to 110f is switched. Therefore, the accumulation time of the phase adjustment buffer 26 is set by the accumulation time setting unit 25, and this accumulation time is set. Only the phase adjustment buffer 26 delays data transmission.

  As described above, the main line video signal 100 output from the camera head 9 is reproduced as the main line video signal 110a output from the CCU 2 through the compression / decompression process and the modulation / demodulation process. As shown in (d) and (e), there is a processing delay. Here, as an example, a case where the processing delay is 9.2 ms is shown. This also applies to the return video signal 118 converted from the on-air video signal 114 and the return video signal 131 returned to the camera head 9, as shown in FIGS. 6 (a) and 6 (b). As an example, a case where the processing delay is 2.5 ms is shown.

  By the way, the processing delay at this time is specific to the models of the camera 1 and the CCU 2. Therefore, if the models are the same, the processing delay time is basically a fixed value that does not vary. Therefore, in the system described with reference to FIG. 5, an accumulation time setting unit 25 is provided, and a fixed value accumulation time setting value command 250 manually operated in advance is manually input from an input means (not shown). It has become.

  Then, the storage time information 251 based on the storage time setting value command 250 is set in the synchronization adjustment buffer 26 from the storage time setting unit 25 so that the main video signal 100 and the main video signal 110a have the same phase. Hereinafter, the accumulation time information 251 necessary for phase alignment at this time will be described with reference to FIG.

  First, the main video signal 110a output from the CCU 2 is selected by the switch 3 in advance. In this case, as shown in FIGS. 6A and 6B, the return video signal 131 has a processing delay of 2.5 ms with respect to the return video signal 115. Therefore, when the phase of the return video signal 131 is changed by one field period of about 16.7 ms as shown in FIG. 5C, the phase of the main video signal 100 is matched with this phase. As shown in (d).

At this time, the processing delay between the main line video signal 100 and the main line video signal 115 is 9.2 ms as described above. Therefore, the phase of the main line video signal 115 in this case is shown in FIG. The total processing delay time at this time is expressed by the following equation (1), that is,
2.5ms + 16.7ms + 9.2ms = 28.4ms (1)
As a result, the accumulation time TD to be set in the synchronization adjustment buffer 26 is set to the following equation (2), assuming that one frame period is 33.3 ms:
TD = 33.0ms-28.4ms = 4.9ms (2)
Given in.

Therefore, in this case, if the accumulation time information 251 is set to 4.9 ms, the main line video signal 110 synchronized with the return video signal 115 can be obtained. Therefore, the accumulation time is calculated based on the calculation of the accumulation time TD. If the set value command 250 is set to 4.9 ms, for example, by manual operation, the main line video signals 110a to 110f output from the CCUs 2A to 2F are kept synchronized with each other in the system of FIG. Further, it is possible to suppress the occurrence of image disturbance due to the switching of the on-air video signal 114 by the switch 3.
JP-A-9-289608 JP 2003-304442 A

  The above prior art does not give consideration to the compatibility of the camera system, and has a problem in efficient model change.

  As already described, the magnitude of the signal delay described above depends on the camera and CCU used in the system. Therefore, for example, if the specification performance is the same as in the same model of the same manufacturer, the magnitude of the signal delay hardly changes even if the individual changes. Therefore, when the combination of the camera and the CCU does not change, or when the specification performance is the same even if it changes, the above-described storage time information 251 need only be set once at the start of use. There is no particular problem with the prior art.

  However, here, when many camera systems are used in a studio or the like as in the prior art described above, for example, because of efficient creation of a program, and in some cases, due to differences in manufacturers, etc. Cameras and CCUs having different performances are mixed, and for example, the camera of manufacturer A and the CCU of manufacturer B are combined, or the CCU of manufacturer D is applied to the camera of manufacturer C.

  Then, in this case, in the above-described conventional technique, it is necessary to reset the accumulation time by the above-described manual work for each new combination. Therefore, as described above, the conventional technique is efficient. This can cause problems with changing the model.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a synchronous automatic adjustment device in which setting of an accumulation time for a synchronous adjustment buffer is automatically given.

The object is to provide a plurality of camera systems comprising a pair of camera body and camera control device, and select one of a plurality of video signals acquired by each camera body and output from the camera control device to be an on-air video signal. In addition, in the synchronous automatic adjustment device that transmits the on-air video signal as a return video signal to each of the plurality of camera bodies, each camera control device of the camera system transmits the return video signal to a set delay time. And a delay means for delaying the output and a phase difference detection for detecting a phase difference between the delayed video signal acquired by the camera body and received by the camera control device. and means, setting means for setting said delay means a delay time corresponding to the phase difference issued該検, wherein the delayed said litter The video signal is supplied to the camera body that is to the camera control unit and the pair respectively are synchronized with each other in the video signals output from each of the camera control unit is achieved so as to be maintained.

At this time, the plurality of video signals output from each of the camera control devices are HDTV video signals, and the return video signal is an SDTV video signal obtained by down-converting the on-air video signal. The camera body transmits, to the camera control device, the video signal synchronized with the delayed return video signal supplied from the paired camera control device with a specific processing delay. The phase difference detecting means starts counting by a frame synchronization signal included in the delayed return video signal and detects a count value held by the frame synchronization signal included in the received video signal as the phase difference. is intended, the setting means may be a time according to the count value is set as the delay time, again, The combination pairs of the camera body and the camera control unit when it may be is wireless configuration.

  According to the present invention, since the setting of the accumulation time for the synchronization adjustment buffer is automatically given according to the phase difference between the return video signal and the main video signal, no consideration is required for the compatibility of the camera system. Efficient camera operation can be easily handled by changing the model freely.

  Hereinafter, an automatic synchronization adjustment apparatus according to the present invention will be described in detail with reference to embodiments shown in the drawings. At this time, FIG. 1 shows an embodiment of the present invention. This is the same as the prior art shown in FIG. 5 except that an automatic phase difference detection unit 200 is newly provided. A setting unit 300 is provided, and the accumulation time calculation setting unit 300 calculates the accumulation time set value command 252 from the hold value 203 and sets it in the synchronization adjustment buffer 26. Other configurations are changed. There is no.

  Therefore, the embodiment of FIG. 1 is also described in FIG. 5 except for the operation of generating the hold value 203 by the automatic phase difference detection unit 200 and the operation of generating the accumulation time set value command 252 by the accumulation time calculation setting unit 300. This is the same as the prior art, and therefore, description will be given below with an emphasis on the operations of the automatic phase difference detection unit 200 and the accumulation time calculation setting unit 300.

  First, the automatic phase difference detection unit 200 receives the parallel video data 109 output from the blanking information addition unit 20 and the parallel video data 119 output from the S / P conversion unit 27, and the phase difference between these data. Is detected, and an accumulation time set value command 203 is automatically calculated in response to this and supplied to the accumulation time calculation setting unit 300.

  For this reason, as shown in FIG. 2, the automatic phase difference detection unit 200 includes an F_Sync detection unit 700 and a clock synchronization unit 701 that receive parallel video data 109 as an input, an F_Sync detection unit 702 that receives parallel video data 119 as an input, and a counter. A unit 703 and a hold unit 704. Here, F_Sync is a frame synchronization signal.

  First, the F_Sync detection unit 700 receives the parallel video data 109 and detects the F_Sync signal 600 therefrom. The parallel video signal 109 is composed of video data, header information indicating a frame (33 ms), a field (16.6 ms), and the like. Therefore, SAV (Start Active Video) in the header information is detected, and an F_Sync signal 600 is generated and output. At this time, since the parallel video data 109 conforms to the HDTV standard, the reference frequency is 74 MHz.

  Further, the F_Sync detection unit 702 receives the parallel video data 119, similarly detects the SAV of the header information, and extracts and outputs the F_Sync signal 603 as shown in FIG. 3 (b). At the same time, the clock 604 is detected from the parallel video data 119. At this time, since the parallel video data 119 is based on the SDTV standard, the reference frequency is 27 MHz, and therefore, the reference frequency is different from the parallel video data 109 based on the HDTV standard.

  Therefore, the clock synchronization unit 701 performs sampling with reference to the clock 604 having a frequency of 27 MHz, and extracts a signal appearing immediately after the clock 604 from the F_Sync signal 600 having a frequency of 74 MHz, as shown in FIG. This is output as a synchronous F_Sync signal 601.

  Next, the counter unit 703 uses the F_Sync signal 603 as a trigger, and starts counting the clock 604 each time it occurs, and increments the count value 605 as shown in FIG. The hold unit 704 receives the count value 605 of the counter unit 703, holds it with the synchronous F_Sync signal 601, and outputs it as the hold value 203 as shown in FIG.

  Therefore, the accumulation time calculation setting unit 300 sequentially calculates the phase difference between the F_Sync signal 603 and the F_Sync signal 601 from the input hold value 203 as shown in FIG. As a result, the return video signal 117 is delayed, and then the return video signal 118 is output from the time point determined by the storage time information 301. To be.

  Next, the calculation of the phase difference at this time will be described. Here, for example, it is assumed that the hold value 203 is “200000”. This means that the count difference between the F_Sync signal 603 and the F_Sync signal 601 is “200000”. On the other hand, at this time, the reference frequency of the F_Sync signal 603 is 27 MHz. Then, from this, the time according to the phase difference can be calculated by the following equation (3).

Time T (s) according to phase difference = hold value / reference frequency …… (3)
= 200000/27000000
= 0.0074 (s)
That is, in this case, the difference between the F_Sync signal 603 and the F_Sync signal 601, that is, the phase difference is 7.4 ms in terms of time.

  In this case, the accumulation time calculation setting unit 300 calculates a delay time of 7.4 ms and outputs the delay time 7.4 ms as the accumulation time information 301. Therefore, since the accumulation time of the synchronization adjustment buffer 26 is set to 7.4 ms, the phases of the parallel video signal 109 and the parallel video signal 119 are matched, and as a result, a main line video synchronized with the return video is obtained. .

  Therefore, according to this embodiment, since the setting of the accumulation time for the synchronization adjustment buffer 26 is automatically given according to the phase difference between the return video signal 115 and the main video signal 110, what is the compatibility of the camera system? Efficient camera operation can be easily handled by changing the model without any consideration.

It is a block block diagram which shows one Embodiment of the synchronous automatic adjustment apparatus by this invention. It is a block block diagram of the automatic phase difference detection part in one Embodiment of this invention. It is a timing diagram for demonstrating operation | movement of the automatic phase difference detection part in one Embodiment of this invention. It is explanatory drawing which shows an example of the usage condition of a wireless camera system. It is a block block diagram which shows an example of the wireless camera system by a prior art. It is a timing diagram for demonstrating the synchronous condition of a main line video signal and a return video signal.

Explanation of symbols

1: Camera 2: CCU
3: Switcher 4: Studio demodulation room 5: Speaker 6: Reference video signal generator 7: Microphone 8: Speaker 9: Camera head 10: S / P conversion unit 11: Active video extraction unit 12: Compression unit 13: Multiplexing Unit 14: Microphone 15: S / P conversion unit 16: Modulation unit 17: Demodulation unit 18: Separation unit 19: Decompression unit 20: Blanking information addition unit 21: P / S conversion unit 22: P / S conversion unit 23: Down converter 24: Same base unit 25: Storage time setting unit 26: Synchronization adjustment buffer 27: S / P conversion unit 28: Active video extraction unit 29: Compression unit 30: S / P conversion unit 31: Multiplexing unit 32: Modulation unit 33 : Demodulation unit 34: separation unit 35: expansion unit 36: blanking information addition unit 37: P / S conversion unit 38: VF (video finder)
39: P / S conversion unit 40: Antenna 41: Antenna 42: Antenna 43: Antenna 200: Automatic phase difference detection unit 300: Storage time calculation setting unit 700: F_Sync detection unit 701: Clock synchronization unit 702: F_Sync detection unit 703: Counter unit 704: Hold unit

Claims (3)

A plurality of camera systems each including a camera body and a camera control device are provided, and one of a plurality of video signals acquired by each camera body and output from the camera control device is selected as an on-air video signal. In a synchronous automatic adjustment device of a method of transmitting a video signal as a return video signal to each of the plurality of camera bodies ,
Each camera control device of the camera system includes:
Delay means for outputting the return video signal by delaying a set delay time; and
Phase difference detection means for detecting a phase difference between the video signal acquired by the paired camera body and received by the camera control device, and the delayed return video signal ;
Setting means for setting a delay time according to the detected phase difference in the delay means,
The delayed return video signal is supplied to the camera body paired with the camera control device so that the video signals output from the respective camera control devices are kept synchronized with each other. Synchronous automatic adjustment device characterized by In the synchronous automatic adjustment device according to claim 1,
The plurality of video signals output from each of the camera control devices are HDTV video signals, and the return video signal is an SDTV video signal obtained by down-converting the on-air video signal,
The camera body transmits the video signal synchronized with the delayed return video signal supplied from the paired camera control device with a specific processing delay to the camera control device,
The phase difference detection means starts counting by a frame synchronization signal included in the delayed return video signal, and uses a count value held by the frame synchronization signal included in the received video signal as the phase difference. Is to detect,
The synchronous automatic adjustment device , wherein the setting means sets a time according to the count value as the delay time . In the synchronous automatic adjustment device according to claim 1,
A synchronous automatic adjustment device, wherein the camera body and the camera control device of the combination pair are wirelessly configured .

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