Remind me again why we ditched analog TV.
> Date: Wed, 12 Mar 2014 14:41:00 -0400
> From: [log in to unmask]
> Subject: Re: [ARSCLIST] Lip Sync, was Radio voices, was Toothpaste
> To: [log in to unmask]
> Hi, All,
> Lip Sync (or loss thereof) is apparently the price we pay for progress.
> I have not followed the latest in video and audio compression tools,
> but the problems started as soon as we had digital frame synchronizers
> that could delay incoming video so that it was in-time with plant video.
> Since the two reference generators were not in sync, the delay was
> variable. Good design was to use a tracking audio delay at the frame
> Enter digital production switchers...these had variable delays based on
> the amount of effects (some would compensate) and the audio console in
> the paired audio control room needed to have a delay to match the
> production switcher.
> Then, of course, when moving from uncompressed video in the plant to
> compressed video transmission, what Tom said...
> Now, it seems that cable companies MAY be recompressing the DTV signals
> to meet their bandwidth requirements, so there is another chance for
> audio and video to get out of sync.
> I went into full-time audio tape restoration in the middle of this and
> have not kept abreast of the developments in video system design. I was
> part of the team that put in several early HDTV pilot facilities, but
> left after the first few mostly file-based plants were built.
> I'm sure others know more, but keeping audio and video locked together
> has been a challenge for probably close to a quarter century. A single
> frame delay is not all that noticeable. Add a few more and it becomes
> On 2014-03-12 2:01 PM, Tom Fine wrote:
> > The audio out of sync with video seems to be one of the many prices of
> > "progress", moving to digital TV. As I understand it, different digital
> > compression and transmission protocols are used to send audio and video,
> > and often don't arrive at the viewer's TV set at the same time.
> > Hopefully one of the broadcast technical pros on the list can explain
> > this better.
> -- Richard L. Hess email: [log in to unmask]
> Aurora, Ontario, Canada 647 479 2800
> http://www.richardhess.com/tape/contact.htm Quality tape transfers --
> even from hard-to-play tapes.