DATA / STREAMING

SRT Latency & Buffer Calculator

Estimate an SRT latency starting point from measured RTT, a disclosed multiplier, and stream bitrate.

This is a planning heuristic, not an automatic link setting. Confirm the current SRT implementation guidance, observe loss and retransmissions, and test the real path before production.

Suggested Starting Latency 180 ms
Approx. Payload Capacity 225 KB
Approx. Payload Packets 171 pkt
Model assumptions: latency = max(measured RTT, 20 ms) × selected multiplier. The 20 ms model floor follows current Haivision configuration guidance for very low RTT inputs. Payload capacity uses the selected bitrate and 1,316-byte packet payload; it excludes protocol, encryption, FEC, and container overhead.
Measured RTT used directly: 45 ms.

Common SRT Use Cases

REMI / Remote Production

Prepare an initial test value for an ISO camera contribution path, then tune it with observed RTT, loss, retransmissions, and receiver behaviour.

Cloud Vision Mixing

Pushing live venue feeds to AWS/Azure instances running OBS or vMix in the cloud, requiring stable ingestion buffering to handle fluctuating cloud routing.

Bonded Cellular (LiveU / Aviwest)

Use a higher test multiplier on variable cellular paths, while recognising that latency alone cannot guarantee recovery from sustained loss or bitrate shortfall.

Global Syndication

Use measured intercontinental RTT as one input, then confirm the chosen value under representative congestion and route changes.

Design Stable Links

Save this calculator for your next remote production or cloud broadcast.

What is the SRT Latency & Buffer Calculator?

Provides a transparent RTT-multiplier worksheet for choosing an initial SRT latency value and estimating how much stream payload fits within that time.

It cannot observe loss bursts, congestion, route changes, encoder behaviour, or receiver implementation. Those must be checked on the actual contribution path.

Real-World Use Cases

Useful before a link test to compare the latency cost of several RTT multipliers and to document the selected starting point.

During the test, use sender and receiver telemetry to balance delay against recovery behaviour, and keep a rollback value.

Technical Methodology

Uses SRT latency = RTT multiplier × RTT, with a 20 ms input floor for lower RTT values. A 4× multiplier is only a rule-of-thumb starting point for a reasonably good path, not a universal optimum.

Confirm the current guidance for the exact SRT implementation and tune from live packet-loss and retransmission telemetry. Use the Video Bitrate Calculator only as a separate planning estimate.

Related Engineering Tools

Streaming Latency Calculator Video Bitrate Calculator All Broadcast Tools