What is lip sync error and why should
trial attorneys be aware of its danger?

When a timing mismatch between the
audio and visual signals occurs in video
processing, the credibility of the witness
is at stake. In particular, if there is video
delay, it could result in:

1) If it's your video of your opponent's
    witness, you may face a motion to
    exclude your video from trial. It may
    even result in a mistrial.

2) If your witness is on video, the jury
    may have a negative reaction to the
    testimony. This comes from a slight
    mental conflict when the viewers are
    aware of some problem but cannot
    quite pin down the cause. Without
    realizing why, the jury members can
    have feelings that something is not
    quite right with the witness.

When a video signal has been processed through
video compression, digital video effects, or other
processes, the result can be "video delay". This
means that the audio and visual elements are no
longer exactly in synchronization. The audio is
a little earlier than it should be in such a video.
It's also possible for some equipment to cause
audio delay but this is much less common. This
means that when a number of processes occur in
video production, it's more likely that the video
delay will exceed any audio delays.

The result, when a witness is testifying on video,
is that the sounds of the words are heard slightly
before the corresponding lip movements. When
this timing error is great (which is not often),
it is obvious to the viewer and understood. The
danger is when the video delay is between about
1/30th of a second and about 1/5th of a second.
It is around this range of timing error when the
viewers are likely to have a subconscious aware-
ness of a problem and ascribe it, incorrectly, to
something being wrong with the witness.

In the broadcast television industry, the Radio-
communication Study Groups of the International
Telecommunication Union allows for no more
than 1/60th of a second of visual delay related
to audio-visual sync.

For more information, phone
Jonathan Whitcomb at 562
989-1334 or use email.