Geeze, Wayne, could it really be that hard? I'm not a broadcaster and certainly not an engineer, but poking a button to delay the audio a frame at a time until the picture caught up with it seems like something any intern should be able to do. Do we still need to invent that button? I slip tracks all the time to fix lipsync errors when editing video and just "earballing" it to get within a frame or so is quick and easy and usually good enough (and better than a lot of what I see broadcast.) I do suspect that for broadcast this wouldn't be quite as simple as I make it sound since the delay likely would vary from source to source (but hopefully not slip within a particular segment.) I certainly didn't mean to be too harsh on EVERYone involved in getting the signal out on the airwaves, but shouldn't there be a live human being watching at some point doing some simple Q.C. on the lipsync in addition to watching the waveform monitor?

If it's a musical performance a lot depends on how well the artist can lip sync his own stuff since a lot of live television performances are just lip sync in the first place. Not much an engineer can do about that. Possibly if the music is ahead of the singer it could be improved, but only until the singer got out of sync again.

Well, I think you can imagine that no-one is interested in just a symptomatic fix, but would really like to fix the problem wherever it arises. Someone at the end of the chain is going to go crazy as the delay changes, maybe from program-to-commercial-to nth commercial and back, and maybe even during the program as audio and video feeds are switched separately between different backup delivery means, or from source location to location. It's messy, and people are working to clean up the mess at every stage.

Lipsync in the MPEG age
 

I get to deal with this mess everyday in my career in broadcasting. What you are seeing is the variables of MPEG transmission as broadcasting rushes headlong in to digital.

So many broadcast plants, remote truck transmissions, news uplinks, et al are digital in one form of MPEG or another. With a few frame syncs thrown in along the line to get it back to analog. And that is just transmission. Origination at the station is from a server for the most part. Wheel of Fortune is just a server file. Edited on a computer. MPEG again.

With MPEG, everything is motion. The the more motion, the more the processing, the bigger the file/frame, the more the bandwidth, the more the pic slows down in relation to the audio. Eventually it catches up.

And then there are the converter boxes that are being used to get separate digital SDI (Serial Data Interface...which is the standard digital signal used in normal 4x3 transmissions or 16x9 lo def) video and analog audio combined to one data stream. Hi Def is another monster using 270 meg transmission.

I had a problem tonight with a black box from a long-haul transmission service that came to me with the audio wired out of phase.

You could have a news report from a landslide in Cali that goes;

Analog 4x3 camera to digital satellite uplink
Digital downlink to long-haul digital fiber transmission to studio
Digital switching in studio
Digital or analog uplink to satellite for distribution
Digital or analog downlink at cable headend or local station
Local digital conversion and TX for over-the-air 8VSB transmission or
Digital conversion to QAM 256 for digital cable box at home
Digital processing in your home plasma set

Add a few layers for transmission from overseas.

Just watch a NFL game and watch the processing try to keep up with a fast-moving deep pass on the wide shot, game coverage. StutterVision. Some networks are better than others. You can see it on any old beast that we all love. And that signal is a down-converted version that we call a "center cut" (4x3 analog from the Hi Def 16x9, 270 meg, digital original) version of the highly touted Hi Def original from the stadium. Another conversion which can be done at the origin or at the end transmission.

And different Hi Def plasma set mfrs have different processing in their sets. It pays to shop and compare. Watch out for sale sets. Older processors just like a cheap computer.

There will be a test later,

Dave A

Color back then probably didn't look as good as it did now because of the limitations of early NTSC. NTSC signals generated by a video game system, DVD player, and satellite receiver are much better than what was used to capture and generate video back then, since it was out of phase.

Though from what I hear, the 15GP22 and 21AXP22 triniscopes produce a beautiful color picture. This is why I want a set with one of these CRTs, for the rich color picture, despite the limitations of early NTSC.

Bryan, I often watch Jeopardy on channel 5 from Cleveland and have never (yet) noticed any discrepancies as far as synchronization goes. That station, like all other TV stations in town (3-5-8-19-23-25-43-55-61), is converting to digital, but even at that there is no problem with sync--none that I've ever noticed, anyhow. Perhaps the trouble is with the local network affiliate you mention. Is that one of the two network affiliates in Salisbury or (if you have cable) one of the network stations in Washington or Baltimore? Seems to me a lot of small-town network affiliates have these problems a lot more frequently than their counterparts in major cities.

BTW, I'm still wondering if you ever saw anything from the channel 36 translator in Virginia that's supposed to relay NBC channel 10 (WAVY-TV in Portsmouth, IIRC) to Salisbury and surrounding areas (including Federalsburg, I would think). I saw a coverage map some time ago for that translator on a listing from 100000watts.com that showed the station as having fairly good coverage into your area of Maryland. Have you ever seen this station on any of your TVs that are not on cable? I would think, considering how small the state of Maryland is or seems to be (it looks awfully small on a map), and by its proximity to Virginia and Delaware, any translator station anywhere near those three states should cover the entire tri-state area with no trouble at all.

Jeff, I'll have to give that 36 a try. I do have a halfway decent UHF only antenna in the attic, aimed south. I'll try it first on my "daily driver" NAP Sylvania in the living room. I have seen a little something on the screen as I was passing through the 30's on the older continous tune UHF sets but I thought it might be the Howard University PBS station out of DC (32). Maybe I can remember to do that tonight. I have seen WAVY before when the DXing was good, but not in some time.

The local station in question is WMDT-47 Salisbury. They are kinda second-rate compared to the other local, WBOC-16. I have also noticed lots of videotape troubles on 47 from time to time. The lipsync will sometimes be off by over a second(or more).

Update: neither the Sylvania nor the little Samsung in the bedroom show anything on 36; I tried the '68 Zenith I just got & you could see a little bit of change in the snow around 36 but that was it. I am curious about that station, where they are located, etc. If it is in "mainland" Virginia & fairly low power this just might be too much of a stretch. Somewhere once I came upon a website listing lots of low power tv stations & was amazed at their numbers. There were quite a few in our area according to the site, though none show up on the screen. There is a PBS translator in the next town, has been for years, but even at such a close distance I cannot pick it up. A TV station that only covers one small town hardly seems worth the effort.