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Lip Sync Problems with New Digital Displays?
An anonymous reader writes "With all of the new digital TV displays flying out the door, its easy to to think that life is good on the road to high definition. But, as Audioholics reports today, cheaper displays are using inexpensive processors that result in video delays of up to 60 milliseconds (that's about 2 frames of video). This means that the video processing (deinterlacing, video scaling, etc) delays the picture so that the audio is out of sync. Add to this inherent delays in some LCD and plasma units and the problem can be more than a little noticeable. As of right now only a few manufacturers are building audio lip-sync delay into their products to compensate."
I was wondering why Ron Jeremy's tongue was trailing behind the licking sound.
Trolling is a art,
Now the lips in my old gozilla movies will be in sync! Deaf people everywhere are rejoycing!
"Let's Fight!"
<mouth keeps moving for several seconds>
Oh, wait. Those kung foo movies were always like that.
How exactly is this a work-around? Will you really notice if the entire feed is delayed by a fraction of a second? It seems to me like the right thing to do-- impose an external constraint that the audio and video feeds should be synchronized rather than count on the processors to be fast enough to make the difference unnoticeable. It should help in the future if people want more sophisticated transformations to be applied to either component of the stream.
Video games depend on low latency between input (at the gamepad) and output (at the CRT and speakers). Video game systems manufactured for sale in the United States after 2006 will include some sort of digital TV output. These digital TV sets introduce a significant latency into the chain. So what will happen?
Will you really notice if the entire feed is delayed by a fraction of a second?
If the feed is coming from a video game console that's responding to live user input, I'll certainly notice llaagg. A delay of 60ms can spell the difference between a hit and a miss, adversely affecting game scores.
There's no reason to build expensive circuitry to correct the problem. You can use the laws of nature to resynch your video!
For a video lag of 60 milliseconds, you only need to step back 20.4174 meters from your TV before the speed of sound will correct the synchronization problem.
-3Suns
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The Revolution will be Slashdotted
I find that if I get ever so slightly drunk, the delay in my mental processing of the auditory information compensates nicely.
I was working on a video conference system a few years ago, where latency is everything. We got a huge $15k plasma display (at the time), only to discover it had something like 90 ms of latency! Since we were already pushing our latency budget by sending signals across the country and loosing frames here and there through video processing equipment and codecs, that 90 ms was more than enough to push us over the edge and make the system very difficult to use for natural conversation, and throw the audio/vidio sync visibly out of whack. The plasma had to be replaced. Three frames may not seem like a lot, but it is quite noticable.
I've delt with a lot of high-priced high-quality plasma systems over the years, and the lesson is definitely "Buyer Beware". The high quality 56" plasma systems can be stunning, but remember that you're also investing thousands in a device with a fairly limited lifetime, and no real industry-wide quality standards and more marketing buzzwords and cheap tricks than you can shake a stick at.
If you using plasmas as a computer display you will see even more artifacts. I've seen widescreen plasmas that could not accept any resolution modes of a correct aspect ratio. Many displays use a great deal of image processing to apply tricks to make the display look good, but sometimes the processing can seriously disturb things like computer text. I've seen apparent color segmentation problems on a lot of displays, and just a lot of artifacts in general.
-braddock