Audio and video integrated central control scheme of lecture hall, realizing one-button system-wide linkage.

Friends who have done lecture hall and multi-function hall projects must have a deep understanding.

A standard lecture hall is filled with a lot of equipment, such as hand-in-hand conference host, audio processor, power amplifier speaker, LED large screen, video matrix, Yuntai camera, recording and broadcasting host and power sequencer.

In the venue without central control, special personnel should be present in advance for each meeting: turn on the sequencer, turn on the big screen, adjust the conference host, switch the signal source, align the camera and debug the audio parameters. It takes several minutes for a set of processes to go down. When it is operated by non-professionals, it is easy for the signal to be cut off, the microphone to be silent, the camera to deviate, and the conference site will directly roll over.

After the meeting, I often forget to turn off the power amplifier and the big screen, and the equipment will be energized without load for a long time, which will accelerate the aging and shorten the service life.

The core significance of the integrated control of audio and video is not a tall stunt, but to package the professional and complicated equipment operation into simple scene buttons, so as to realize one-click meeting and one-click dismissal, and even the conference staff who do not know the technology can skillfully operate the whole lecture hall.

1. What parts does the integrated central control system consist of?
The central control is equivalent to the "brain center" of the whole lecture hall. It does not participate in the transmission of audio and video signals, but is only responsible for issuing control instructions and scheduling all peripherals to work together.

A complete central control system is divided into five parts.

Central control host (core)
With RS232, RS485, IR, IO relay and TCP/IP network interfaces. It sends control instructions to audio, video and power equipment through various protocols, and is the command center of the whole system.
Touch panel of operation terminal
The mainstream uses an 810-inch wall-mounted touch screen, which is installed at the entrance of the venue or the control room. The Chinese visual interface can trigger the preset scene by clicking the button. Large-scale projects can be additionally equipped with wireless mobile touch screens.
Extended interface module
The relay module is connected with the power supply sequencer; Infrared emission rod controls projection; Serial port docking audio DSP, video matrix, conference host; Network interface docking network matrix, recording and broadcasting, Dante audio equipment.
Controlled peripheral equipment
Hand-in-hand conference system, audio processor, power amplifier, LED/projector, video matrix, Yuntai camera, recording and broadcasting host, power sequencer.
The transformation is beneficial: the old lecture hall is upgraded, and most of the original audio, conference and display equipment can be directly used, without all new ones. As long as the equipment supports serial port/infrared/network protocol, it can be connected to the central control to realize one-button linkage, greatly reducing Party A's transformation budget.

Optional operation and maintenance background
Remote management on the web page allows the engineer's computer to check the equipment status and modify the scene logic without running to the site to debug the program.
Two, the lecture hall four core one-key scene logic (engineering can directly refer to the writing program)
Excellent central control is not a simple switching device, but a complete conference flow is solidified into a scene script, each action is set with a reasonable delay, and the audio and video switching time sequence is strictly observed.

Scene 1: One-click conference begins
Click [Meeting Start] on the touch screen to automatically execute:

The power sequencer is powered on in sequence: matrix, central control, conference host and recording and broadcasting are started first; Turn on the audio processor and power amplifier after the delay;
The large screen/projector is automatically turned on and switched to the default signal;
The Yuntai camera automatically calls the preset position of the rostrum;
Audio DSP loads [local conference] preset, opens microphone channel, sets basic gain, and closes idle channel;
The video matrix switches the PPT signal of the local computer to output to the big screen; Complete all pre-meeting preparations in 30 seconds, without manual debugging item by item.
Scenario 2: One-click remote video conference
Click [Teleconference], and the system will automatically switch the state of the whole set of software and hardware:

The video matrix is switched to the video conference terminal signal;
The camera switches the online conference framing preset;
DSP automatically loads the exclusive preset for teleconferencing: turn on AEC echo cancellation and intelligent noise reduction, adjust microphone gain, and avoid the problem of online conference echo howling;
Can be customized to open the recording and broadcasting host, automatically start the meeting recording.
Scenario 3: One-click Presentation Mode
One-click switching when making a report or PPT presentation:

Matrix switching lecture computer HDMI signal output large screen;
Audio switching to local microphone input channel;
DSP loads the speech amplification parameters to optimize the loudness of human voice;
The camera jumps to the speaker's preset position.
Scenario 4: One-click Meeting End (Safe Shutdown)
Key points: Never turn off all the power directly, and strictly follow the iron law of "turn on the power amplifier first and then turn it off".

Turn off the power amplifier output first to protect the speaker unit;
The projector/large screen issues a shutdown command to reserve a cooling delay for the projector;
The camera returns to the standby position;
Recording and broadcasting stops recording and saving files;
After the delay, the power supply sequencer completes the power-down in reverse order.
Three, the project landing high-frequency trampling points, integrators must collect.
After many central control projects are completed, some actions such as button clicking are not executed and the scene is disordered, mostly due to poor consideration of the details in the early stage.

Confirm the equipment control protocol in advance
In the early stage of the project, it is necessary to collect RS232/network control protocol documents of all controlled devices. Some minority domestic devices don't open the control protocol, so they can't be linked, and they can't wait until the debugging stage to find the problem.
Action delay cannot be omitted.
Projection and host power-on itself need start-up time, and all instructions cannot be issued in batches at one time. Each execution step is reserved with a corresponding delay, otherwise the equipment has not been started, the instruction reception is invalid, and the scene execution is incomplete.
Infrared control is limited, and serial port control is preferred.
When the infrared rod is used to control the projection, it needs to be close to the receiving window of the equipment; The enclosed cabinet is easy to block infrared signals, and RS232 serial port control is preferred if conditions permit, which is much more stable than infrared.
It is forbidden for the central control relay to directly drive the high-power load.
The central control relay only does signal triggering, power amplifier and other high-power equipment, all of which are carried by the power sequencer to avoid burning the central control module.
Each scene parameter is isolated independently from each other.
For local meetings and teleconferencing, two sets of DSP preset parameters are stored separately, and the corresponding configuration is automatically called when switching scenes. Do not share the same set of parameters to prevent the teleconferencing from echoing.
Manual emergency access must be reserved.
This is a design that is easily overlooked in many projects. The central control is only the control layer, without going through the audio and video signal link. Even if the central control host fails, all audio and video equipment can still be manually operated by local buttons, and the central control cannot be broken, and the whole lecture hall can't be held directly.
Four, how to choose the new project VS the transformation of the old lecture hall?

V. Several Questions Frequently Asked by Party A
Q: Does the central control have to be equipped with a touch screen? A: Wall-mounted touch screen is the most intuitive operation mode on site; For small projects with limited budget, you can also use web page control, tablet and browser to access the page.

Q: Can all devices do one-button linkage? A: The equipment needs to have serial port, network or infrared receiving ability. Completely old equipment without control interface can only control the power supply on and off, and can't realize signal switching and parameter adjustment.

Q: If the central control breaks the venue, will it be abolished? A: In qualified engineering design, the central control is only responsible for issuing instructions, and audio and video signals do not go through the central control. If the central control fails, the equipment can still be manually operated on the panel to ensure the use of basic meetings.

The essence of integrated central control of lecture halls is not to show off skills, but to solidify standardized meeting procedures into equipment.

A set of excellent lecture hall projects should not only make the sound clear and the picture stable, but also lower the use threshold. Let the conference staff who don't know professional audio, with the click of a button, can handle the whole complex system and reduce the probability of on-site rollover, which is the real value of central control.