SMPTE seeks information on lip sync errors

SMPTE is reviewing all aspects of audio-video synchronization errors in broadcasting, in order to recommend practical solutions

SMPTE said there is an increasing awareness that audio-video synchronization errors in broadcasting, usually seen as problems with lip-sync, are occurring more frequently than they used to and often with greater magnitude.

The Society of Motion Picture and Television Engineers S22 Committee on Television Systems Technology has formed an Ad Hoc Group on Lip Sync Issues to review all aspects of this problem and make recommendations for solutions.

SMPTE has issued a Request for Information from interested companies or individuals, particularly relating to sources of differential audio-video delay in television production, post-production, and distribution; audio-video delay issues through professional MPEG encoding and decoding systems; and differential audio-video delay arising in consumer receiver, decoding and display devices.

Also of interest is out-of-service methods of measuring differential audio-video delay; in-service (during program) methods of measuring differential audio-video delay; and devices for correcting differential audio-video delay at different points in the broadcast chain.

SMPTE said it is particularly interested to hear from manufacturers with practical solutions or proposals for measurement and correction of audio-video synchronization errors, and those willing to participate in development of related standards.

Responses should be sent to the ad hoc group chair, Graham Jones of NAB at: or by calling 202-429 5345.

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