Overview
IEC TS 62312-1-1:2018 - Guideline for synchronization of audio and video (Part 1-1: General measurement methods) provides general, practical guidance for measuring time alignment between audio and video outputs. This second edition (2018) replaces the 2008 edition and adds a new Annex B on audio latency measurement and editorial comments arising from SMPTE review. The document is a general part of the IEC 62312 series and defines the measurement framework used by the more specific methods in other parts of the series.
Key topics and technical requirements
- Measurement scope: General methods to determine time differences between audio and video outputs from devices and systems (the Equipment Under Test - EUT).
- Test signal source: Use of synchronized reference audio/video signals (signal generators, test discs) with zero or a specified inter-signal delay.
- Measurement chain: Block-diagram approach - test signal source → EUT → measuring instruments (captures both video and audio outputs for delay analysis).
- Measuring conditions: Requirements for power and environment:
- Power supplies: AC/DC at manufacturer-specified voltages; typical tolerance ±1% (±5% allowable if it does not affect results). AC frequency 50/60 Hz (±2%); AC harmonic content ≤2%; DC ripple ≤0.1%.
- Environmental: ambient temperature around 20 °C, relative humidity ≈60% ±15%, air pressure ≈96 kPa ±10 kPa.
- Warm-up and initialization: EUT should be powered and stabilized (typically 5 min) and initialized before measurement.
- Settings: General settings default to manufacturer defaults; functions affecting sync should be specified or disabled if not relevant.
- Measurement types: Guidance covers individual devices (sources, displays, recorders), compound equipment, and reproduced-signal measurement techniques.
- Annex B: Introduces a general test method for audio latency, an important contributor to A/V misalignment.
Applications and users
- Who uses it: AV equipment manufacturers, test laboratories, broadcasters, pro‑AV integrators, product QA and R&D teams, and standards developers.
- Practical use cases: Validate lip-sync performance, qualify displays and encoders/decoders, specify latency budgets for streaming and live-production chains, and verify compliance during design verification and quality control.
- Benefits: Provides repeatable, standardized measurement practices for accurate A/V synchronization assessment and troubleshooting of audio latency and video delay across equipment chains.
Related standards
- IEC TS 62312-2:2018 - Methods for synchronization of audio and video systems (normative reference for specific equipment measurement methods).
- Other parts of the IEC 62312 series provide device‑specific measurement procedures. SMPTE recommendations and industry best practices are referenced and harmonized where applicable.
Keywords: IEC TS 62312-1-1, audio video synchronization, A/V sync measurement, audio latency, synchronization guideline, measurement methods, EUT.