PTP for Media: AES67 and ST 2059-2 Essentials

Tim Tselikovski -

Precision Time Protocol (PTP) is the heartbeat of IP-based media systems. Without accurate timing, ST 2110 flows fall out of sync, audio drifts, and video frames misalign. By 2025, understanding how AES67 and ST 2059-2 use PTP is table stakes for broadcast engineers.

Why Timing Matters

In SDI, timing was handled by genlock signals. In IP, there is no shared clock by default. PTP solves this by distributing time across the network with sub-microsecond accuracy. Every device aligns to a common grandmaster, ensuring audio and video remain locked together.

ST 2059-2

SMPTE ST 2059-2 defines how PTP should be profiled for broadcast applications. It specifies parameters like message rates, domains, and delay mechanisms. Following this standard ensures different vendors’ equipment can interoperate reliably.

AES67 and Audio

AES67, the interoperability standard for AoIP, also relies on PTP. Audio networks using Dante, Ravenna, or Livewire+ can align with video systems as long as everyone follows the same timing profile. This makes cross-domain workflows possible.

Engineering Practices

  • Redundant grandmasters: Always deploy at least two for failover.
  • Boundary/transparent clocks: Use capable switches to keep jitter under control.
  • Monitoring: Track offset and stability continuously; timing failures cascade quickly.
  • Testing: Validate end-to-end timing in lab environments before production.

PTP is invisible when it works and catastrophic when it doesn’t. Engineers who design resilient timing infrastructures prevent countless downstream issues. In a 2110 plant, timing isn’t optional — it’s the foundation.