I Can Hear Clearly Now

Digital TV is great for watching football, because I don’t see the announcers.  I have noticed one problem, since writing glowing reviews of digital TV, or reviews of digital TV glowing.  That is that most programs have noticeable sync problems between the audio and video.

It seems to be due to signal processing time – the audio is easier to process than the video, so it appears first.  Analog TV didn’t have this problem because there was no processing involved – the signals were converted straight to images by hardware, with no software needed.  I find it hard to believe that of all the people it took to create and approve the digital TV standard, not one of them actually saw a digital TV signal and noticed the lip lag.  It’s fairly obvious on most programs.  Most people are accustomed to a bit of audio lag – sound travels slower than light so it is common to see something happen and then hear the sound that goes with that.  But digital TV is the opposite – the sound appears first.  Video lag is so contrary to nature that it is more disconcerting to people than audio lag is.

All they had to do in the standard was have some sort of time stamp in the audio and video data so that they can be synchronized by the receiver.  Maybe they were expecting the receivers to be smarter than they are.  Maybe they noticed the lag but left it in due to heavy lobbying by the lip fixer manufacturers.

For the vision is yet for the appointed time; It hastens toward the goal and it will not fail. Though it tarries, wait for it; For it will certainly come, it will not delay.

Habakkuk 2:3

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This little article thingy was written by Some Guy sometime around 10:11 pm and has been carefully placed in the Technical category.

4 Responses to “I Can Hear Clearly Now”

  1. js Says:

    Does this mean I shouldn’t buy a digital TV yet?

  2. Burrill Says:

    If you had the chance to watch football on Nanny’s new tv, you wouldn’t even think of asking that question.

  3. Some Guy Says:

    Are you going to wait until the TVs have built-in audio sync adjustment? You’ll miss a lot of TV by then.

  4. Buckley Says:

    Is it strictly an issue for signals received over the air? I have not noticed this lag with the HD stations on cable.

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