Assistive Listening Knowledge Base
  • International recommendation (television broadcasting)

Relative timing of sound and vision for broadcasting (Recommendation ITU-R BT.1359-1)

From https://assistivelisteningknowledgebase.org/evidence/itu-r-1998-bt1359/ · record checked 9 October 2026

  • International Telecommunication Union, Radiocommunication Sector (ITU-R)
  • ITU-R

Standards body (International Telecommunication Union, Radiocommunication Sector)

Summary

Sets tolerances for how far television sound may lead or lag the picture, based on viewer tests in Japan, Switzerland and Australia.

Key findings

  • On average, viewers detected an offset when sound led the picture by about 45 ms or lagged it by about 125 ms, and found it unacceptable beyond about 90 ms lead or 185 ms lag.
  • Recommends that the overall sound-to-picture offset not exceed +90 ms (sound early) or -185 ms (sound late).
  • The tolerance is asymmetric: late sound is detected at larger offsets than early sound.

Limits

Television viewing by general audiences, not listeners with hearing loss and not live venues; based on tests from the 1990s.

Read the original

www.itu.int/rec/R-REC-BT.1359-1-199811-I/en

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Cited in

Cite this source

International Telecommunication Union, Radiocommunication Sector (ITU-R). Relative timing of sound and vision for broadcasting (Recommendation ITU-R BT.1359-1). ITU-R. November 1998. https://www.itu.int/rec/R-REC-BT.1359-1-199811-I/en (accessed 9 October 2026).

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