Technical disclosure: the reason why Kystar broadcasting control was selected for the great journey in the party's centenary party

1. Super stability and safety guarantee

In the performance of "great journey", 8 broadcast control servers were overloaded for 30 consecutive days. At the same time, they continuously completed the scene scheduling of the plan, real-time editing and modification and high-quality visual effect output. There were no abnormalities and successfully completed the broadcast control task.

The broadcast control server hardware adopts high reliability components, and the whole machine has carried out air duct optimization, photoelectric isolation and reliability test to ensure smooth heat dissipation of built-in components, reduce the working temperature rise of the system and improve the stability of the system; Through a large number of extreme environmental reliability tests, including aging under high temperature and high humidity conditions, high temperature and high humidity restart, aging under low temperature conditions, low temperature restart, cold and heat shock, high temperature and high humidity storage, pulse group interference, surge and lightning protection, verify the stability of the equipment.

Execution design and operation security strategy of broadcast control server software, including multi process design, module self verification, active and standby exception monitoring, self recovery of servo program, log management and problem tracking; At the same time, execute operation and data transmission security policies, including operation authority management, standby screen mask, confirmation of key operation items, MD5 file verification and real-time transmission progress monitoring.

2. Synchronous splicing and fusion of multiple online frames

In the performance of "great journey", in order to ensure the absolute safety of broadcast control, all broadcast control servers are equipped with backup servers, including control end and display end. The main server and backup server play in full frame synchronization. In case of abnormal conditions, the main server switches to the backup server, and the output will not have any flicker or delay.

KFS multi online frame synchronization technology is an innovative technology in the industry and has applied for an international patent. It is a technology applied to synchronous playback between multiple servers. High precision time proofreading technology is adopted between machines to ensure the unity of basic clock. Nanosecond synchronous clock provides a strong foundation for synchronization.

The unified rendering technology of multiple files on the same machine can meet the seamless synchronous output of large files after dismantling small files. Hardware resource adaptive technology ensures the maximum use of system resources to complete the output of super large files. It is especially suitable for super large video segmentation and playback to multiple devices to meet the seamless output on the final screen. At the same time, it is applicable to the synchronization between active and standby. In order to ensure that the final screen output has no perceptual switching when the output at one end is abnormal.

3. Hardware decoding and super large material playback

The performance of "great journey" uses more than 10000 "Chinese screens" with a horizontal resolution of nearly 100k pixels. The performance materials all use 4K ultra-high definition materials with high code rate and high frame rate. The control server needs to complete the smooth playback of more than a dozen 4K ultra-high definition materials at the same time. The hardware decoding technology of domestic broadcast control server is fully competent.

Hardware decoding is to decode the high-definition video through the GPU video acceleration function of the graphics card. Therefore, hard decoding can release the CPU from the heavy video decoding operation, so that the server has the ability to play the high-definition video smoothly. GPU / Vpu of graphics card is more suitable for this kind of repeated work with large amount of data and low difficulty than CPU. In this way, the CPU can be relieved, go to battle easily and undertake more other tasks, which is particularly important for the load capacity of the broadcast control system.

Ffmpeg software decoding technology and DXVA hardware decoding technology can effectively reduce the CPU share. Using graphics card hardware decoding, we can realize point-to-point display of 8K screen and smooth broadcast control of 8K materials. Moreover, the broadcast control and playback system can automatically judge whether the material supports hard solution, and make full use of the hard solution ability of the graphics card to improve the overall playback ability of the system. Now, a single graphics card supports 8K video 60Hz hard solution output, and a single multi graphics card supports multiple 8K video 60Hz hard solution output, which is far ahead of the world.

4. Multi machine linkage to realize single machine general control

In the "great journey" performance, a total of 8 broadcast control servers are used, of which 2 servers are used as the main and standby control terminals and 6 servers are used as the main and standby output display terminals. The multi machine linkage control technology realizes the unique control of the control terminal over multiple display terminals and the synchronous control of the main terminal over the standby terminal, and the single machine completes the overall video control.

The broadcast control system fully considers the video broadcast control requirements of the super large stage activity scene. The overall roles of the system are divided into control end, main end, standby end and display end. As the overall control end of multi server, the control end has the most powerful decoding performance and the most comprehensive coding and control ability; As a general broadcast control output terminal, the main terminal has complete programming and control ability and output load capacity; As the backup output terminal, the standby terminal does not have the ability of programming and control, and the output load is completely consistent with the main terminal or display terminal; As the playback end, the display end is controlled by the main end or the control end.

5. LTC time code acoustic photoelectric synchronization

The performance of "great journey" uses more than 10000 LED displays, 150 laser projectors, more than 4300 lighting equipment and more than 500 speaker equipment. In order to ensure the integration of sound, light and electricity, the time code is used for unified control on site. The broadcast control server receives the LTC time code signal and automatically changes the scene plan in real time according to the signal instructions.

The broadcast control system supports the input of LTC and MTC time codes. The scene plan automatically filters the abnormal time code value with the progress of time code playback, pause, call and seek to ensure the smooth playback; Data recording and regular log printing are completed through the server sound card, which is used to analyze the abnormal reception of time code; The broadcast control system supports time code output, and outputs LTC and multi-channel MTC time codes at the same time to complete the synchronous control of multiple groups of equipment. At the same time, the broadcast control system supports the setting of output frame rate and offset time, and generates time code value according to the plan timing or file playback progress.

6. MIDI keyboard real-time accurate broadcast control

In the performance of "great journey", according to the director's joint arrangement requirements, the video control teacher needs to control the progress, switching and brightness of the scene plan in real time. Through the access of MIDI keyboard, the video control teacher can customize the control instructions to the keys and push rods of MIDI keyboard, so as to realize accurate video broadcasting and control.

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