What is Tally?

Tally system

Learn what a tally system is and how it informs live broadcast operations. Discover how Nevion evolves tally lights into software-defined broadcast control, integrating real-time on-air status within VideoIPath Broadcast Control.

In broadcasting, a tally is a visual signal that indicates the live/on-air status of cameras, devices, or media sources during production.

A tally is a fundamental communication tool in live broadcasting and production control rooms. It typically uses a red or green light (often called a tally light) attached to cameras or other production equipment, informing operators, presenters, and crew about the live/on-air status of a source.

Tally systems prevent mistakes in live production—such as looking into the wrong camera or cutting to the wrong source—by giving clear, real-time feedback on which input is active. Beyond lights, modern tally implementations also extend into software, dashboards, and IP workflows, ensuring that every stakeholder—from studio staff to remote teams—has visibility into what’s live and what’s queued.

What Nevion Does

Nevion extends the concept of tally from hardware lights to a fully integrated, software-defined feature within modern broadcast control systems:

  • VideoIPath Broadcast Control: Supports tally management as part of its device and signal control functions. Operators can configure and automate tally signaling across IP-based and hybrid broadcast environments.

  • NMOS IS-07 Support: Nevion integrates tally within NMOS’s “Events & Tally” specification, enabling standardized tally signaling across multi-vendor IP networks.

  • Hybrid Workflows: Nevion ensures tally signaling works across both SDI-based legacy infrastructures and IP-based SMPTE ST 2110 workflows, bridging traditional and modern production setups.

  • Scalable & Remote: With VideoIPath, tally status can be communicated not only to in-studio cameras but also to remote production teams and cloud-based control rooms.

Benefits & Advantages of Tally Systems

  • Clarity: Provides unambiguous indication of live/on-air sources.

  • Error Prevention: Reduces mistakes during live production (wrong camera, wrong cut).

  • Efficiency: Simplifies coordination between production crew and on-air talent.

  • Scalability: Works across multiple devices, from cameras to mixers and virtualized sources.

  • Interoperability: Modern tally systems support standards like NMOS IS-07 for multi-vendor compatibility.

  • Remote Production: Extends tally status to distributed teams and cloud environments.

Comparison with Related Technologies

Feature / StandardDescriptionUse Case
Traditional Tally LightsPhysical lights on cameras showing on-air statusStudio cameras in live production
Software-based TallyDashboards or overlays indicating source statusRemote production or IP-based workflows
NMOS IS-07Open standard for tally/events signaling in IP networksMulti-vendor interoperability in broadcast IP

Common Questions

Q: What does a tally light mean?
A: A tally light indicates whether a camera or source is live (usually red) or preview/standby (often green or amber).

Q: How does tally work in IP broadcasting?
A: In IP workflows, tally signaling is standardized via NMOS IS-07, which ensures that tally events are communicated reliably across devices and vendors.

Q: Does Nevion support tally in hybrid environments?
A: Yes. Nevion’s VideoIPath supports tally signaling across SDI and IP infrastructures, ensuring consistency during the transition to IP.

Q: Why is tally important in remote production?
A: Remote crews need visibility on live sources just like in-studio teams. Nevion extends tally signaling to distributed locations and cloud-based control rooms.