Yiwu TV studio cluster UMD & Tally system

Yiwu Broadcasting and Television Station

I. System Construction Background and Requirements

1. Studio project overview

After the completion of Yiwu Broadcasting and Television Station (hereinafter referred to as Yiwu TV) building, professional system hardware and software integration is critical, as it directly impacts the effective operation of Yiwu TV program production. The main equipment for the Yiwu TV professional system integration comprises the Sub-control Room system, a 400 sqm studio (0#), two 200 sqm studios (1#, 2#), and three 100 sqm studios (3#, 4#, 5#).

Figure 1: Studio actual view

The Sub-control Room system primarily provides centralized scheduling and shared equipment for the 4th-floor studios. The 400 sqm studio is mainly used for in-house variety programs. The two 200 sqm studios (1#, 2#) and one 100 sqm studio (4#) are mainly used for in-house news and commentary programs. The 100 sqm studio (3#) is designed for virtual studio use, and the 100 sqm studio (5#) temporarily serves as a backup studio.

Figure 2: Studio complex signal flow topology diagram

2. Studio complex UMD & TALLY System requirements

During studio program recording, the director needs to know the source name of each signal, camera operators need to know whether their footage is being used by the director, and technical supervisors need to identify which signal is currently on air. These requirements call for a software system that integrates cameras, video switchers, video matrices, emergency changeover panels, and multiviewer systems, enabling staff in different areas to understand signal usage in the studio without verbal communication. This prevents signal mis-switching incidents during recording and reduces the workload of program production.
We call this self-developed software that meets these requirements the UMD & TALLY System (hereinafter referred to as TALLY system).
The TALLY requirements for the Yiwu studio can be summarized as follows:
The TALLY system must have cross-system source name tracing capability.
The TALLY system must support one-click primary/backup state switching.
The TALLY system must support multiple source name display strategies and TALLY schemes on video walls.
The TALLY system must support multiple communication methods with good scalability.
The TALLY system must be simple to operate, require minimal daily maintenance, and run stably.

II. TALLY System Solution

Our TALLY system leverages extensive studio project integration experience, and we have accumulated deep expertise in addressing various studio TALLY requirements. For the Yiwu TV studio TALLY requirements, we developed a targeted solution.

1. Cross-system source name tracing

Several signal sources in the Yiwu TV studio are external signals routed through the sub-control matrix for signal scheduling. These external signals are named "EXT" in the studio source naming system. However, during program recording, studio production staff cannot determine from "EXT" alone whether the signal from the sub-control room is correct. They need to know the source name of the external signal in the sub-control matrix.
The source name cascading function in the TALLY system meets this requirement.

Figure 3: Cross-system source name display

As shown in Figure 3, the source name "EXT 1_MC 1" is composed of source names from two systems. "EXT 1" is the signal's source name in the studio, and "MC 1" is the signal's source name in the sub-control matrix. The TALLY system combines and displays the source names from both systems, providing on-site staff with an intuitive basis for verifying signal correctness.

2. UMD & TALLY primary/backup one-click switching

During system integration, Yiwu TV studio built primary and backup audio/video links to ensure live broadcast safety. The primary switching device is a switcher and the backup is a matrix. When the switcher fails, the matrix handles video production to maintain normal playout. When the primary/backup links switch, the TALLY system must immediately adjust its state to follow the source names and TALLY display of the respective switching device.
The TALLY system uses the emergency changeover switch state as the adjustment reference (switcher in normal state, matrix in emergency state) to implement different source name following and TALLY display for each switching device.

Figure 4: Primary/backup TALLY state one-click switching diagram

As shown in Figure 4, the TALLY system uses a digital I/O collector to capture the emergency changeover switch state and send it to the TALLY server via serial port. The TALLY system uses this as the basis for primary/backup state switching, enabling TALLY to follow audio/video one-click failover.

3. Multiple source name display strategies and TALLY schemes on video walls

In a studio, common source name display strategies include static source names, dynamic source names, and combined static-dynamic source name display. TALLY schemes typically use red-green dual-color TALLY to indicate signal usage.

Figure 5: Video wall source name display and TALLY display

As shown in Figure 5, "PVM_CAM1" uses a combined static-dynamic source name display strategy. "PVW" is the static source name indicating that the corresponding split-screen displays the switcher preview signal. "CAM1" is the dynamic source name indicating that the currently selected source on the preview bus is CAM1. If the preview bus selects "CAM2", the preview source name would display "PVW_CAM2".
The three split-screens below the preview display static source names "CAM1, CAM2, CAM3", which do not change with the switcher bus source selection.
In the Yiwu studio, green TALLY indicates the signal is selected by the PVW bus, and red TALLY indicates the signal is selected by the PGM bus. In Figure 3.1, it is clear that the PGM bus has selected source "CAM1", the preview bus has selected "CAM2", and source "CAM3" is not selected.

4. The TALLY system must support multiple communication methods with good scalability

The devices in the Yiwu TV studio TALLY system support different communication methods. For example, the switcher TALLY output uses GPO, camera TALLY lights are triggered via GPO, the matrix supports both network and serial port, and the multiviewer supports serial port. The TALLY system must support multiple communication methods to integrate devices from different manufacturers into a single TALLY system.

Figure 6: TALLY system device logical connection diagram

As shown in Figure 6, the TALLY server itself supports serial port and network interfaces. Devices supporting serial port or network can complete TALLY display directly through the TALLY server. For GPIO-interface devices, the TALLY system uses external digital I/O collectors to capture and trigger GPIO information, accommodating TALLY display for different devices.
The UMD & TALLY System uses a plugin architecture internally. Supporting new devices only requires writing and testing the corresponding device driver module without affecting the existing system, making extension straightforward.

5. The TALLY system must be simple to operate, require minimal daily maintenance, and run stably

The TALLY system uses a full Chinese interface, suited to domestic user habits and specific workflows. It runs on an industrial embedded control computer platform with a dedicated embedded operating system, immune to system image corruption from unexpected power loss and resistant to viruses. Users only need to power on the system; the TALLY program launches automatically after boot, making operation straightforward.

III. Project History

From March 15 to September 15, 2012, our company carried out the Yiwu TV new building studio cluster integration project, including system commissioning and trial operation. The project covered the central equipment room and six control rooms for 400/200/100 sqm studios, including audio/video systems, sync, clock, control, and TALLY systems, and passed acceptance by the station's project team.
Starting from September 20, 2012, the studios have progressively entered trial operation. Performance during the trial was normal, and all studios have since transitioned to full operational status.