Klarinet Archive - Posting 000292.txt from 2009/01

From: Tim Roberts <timr@-----.com>
Subj: Re: [kl] TV Audio-Video Synchronization
Date: Thu, 22 Jan 2009 12:29:20 -0500

On Wed, 21 Jan 2009 18:06:47 -0500, Matt Reid <qmartialarts@-----.com>
wrote:
> Take this into account...
>
> The camera is probably not picking up the sound through the
> microphone, and is probably farther away from the "action" than you
> may think. ...
> OR
>
> The camera is picking up the audio and video, and the audio is coming
> from a public address system, and the camera is physically located far
> beyond the throw of the speakers. ..

I very seriously doubt that any of these synchronization issues came
from the generating end. Television studios have spent VAST fortunes to
ensure that audio and video are synchronized to within one video frame,
and that they remain that way for weeks on end.

The issue here is almost certainly at the receiving end -- at the
television in your living room. We recently "upgraded" from an analog
television to a fancy-dancy digital HD television. As someone who has
spent 15 years writing operating system drivers for video capture cards,
I find the delay issues fascinating. Standing in my kitchen, I can hear
the new digital TV and one of our old analog TVs simultaneously, and the
audio is as much as 1 or 2 full seconds apart. My kids play Guitar Hero
and Rock Band, where you have to strum a guitar or hit a drum pad at
exactly the right time, and the timing on the digital TV is vastly
different from the old analog TV.

I expected a certain amount of difference, because of the somewhat
unpredictable delays in decoding the digital TV signal, but I'm shocked
at just how much difference there is. I would expect the television
networks to be up in arms about this. After all of the time and effort
spent in getting audio and video in sync, now the individual TV
manufacturers are screwing it up, with apparently no standards to fall
back on.

--
Tim Roberts, timr@-----.com
Providenza & Boekelheide, Inc.

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