There are a number of different ways to deal with audio/video sync problems, but this thread refers to the Automatic Lipsync feature introduced in the HDMI 1.3 spec. In actual fact, this did fix one problem I had. I bought a new Philips TV with a bunch of great video processing features like 240Hz, noise reduction, artifact reduction, dynamic contrast, active control, all things that I paid extra for but couldn't use. In case it isn't clear, that's because when you introduce video processing you slow down the video image causing the picture to lag behind the audio. Human beings are pretty forgiving when what we see happens BEFORE what we hear because light travels faster than sound. Lightening before thunder for example. But when the sound comes first it throws us. So when I finally got a new receiver for Christmas, I was able to start using these features. Now, AUTOMATIC lip-sync (really audio sync - not just dialog) works because the HDTV can tell the receiver exactly how much delay is being introduced. So if the audio and video start off in sync, then this process can put them back into sync. And I needed that. However, far too often by the time we get a movie or TV show it is already out of sync. Automatic synchronization will not (CAN NOT) fix that problem. Unfortunately, it's happening more and more often. lots of videos are captured by people who mean well but don't know what they're doing, or don't take the time to do it right. Worse, digital cable and satellite providers have little quality control for sync issues. And as more channels are introduced and more compression is incorporated into the process, these problems just get worse. Why the show would be out of sync and the commercials NOT, that I can't explain. But I know that half of what I watch on Shaw Direct is at least 100msec out of sync and often way more. The only way to fix that problem is by eyeballing it. You need to get a receiver that will let you see enough of the picture that you can watch the lips move while you slip the audio. And it has to adjust the audio in real time so that you can be assured that the delay you're introducing will STAY that duration after you exit that screen. I have a decent Yamaha receiver and a pretty high-end Sony and both support both automatic lipsync and manual sync. Unfortunately, at least for the present, you're likely to need to adjust at the beginning of just about every show and every movie, until content providers get this problem sorted out. Meanwhile there is just no automatic way of fixing audio/video sync. At least in the old days there was a clapperboard at the beginning of every take of every film. Digital filmmakers have become very lazy in this regard because unlike the old days when audio and video where recorded on different devices, they are both recorded together now. But there are still plenty of ways to screw it up. Sorry this explanation was so long, but I'm an audio engineer and I've been explaining this exact thing to people for years. And so far whenever I try to shorten the explanation I just confuse people. Anyway, to summarize, I've found that once I got my HDTV set up the way I like it, I've left it alone. So I figured out the delay for processing, and that number seldom changes. So automatic lip-sync, even if it works correctly, is mostly useless for most people. You need instead to get a receiver like I described above, with at least half a second of delay, and hopefully more. Then you need to get used to spending a little time re-jigging the sync pretty regularly. Still, it's better than having to put up with out-of-sync TV.
