Hi to all. I am new to this site, and have just a few months ago entered into the HD television world with the purchase of two Hitachi HD plasma screens, DGTech HD Set Top Boxes, Monster Cables, and new Aerial with new cabling and Booster. This is set up in the Maroubra area. I seem to suffer from a normal amount of the regular glitches associated with this new technology, however, frequently my audio becomes delayed, and so, the lip-sync is out, sometimes quite markedly. In the TV World, correct lip-sync is a fundamental requirement. It enables you to experience and enjoy the presentation. When its out of sync, television is crap. Can somebody please tell me if it is just my system that contains this glitch, and if so, how can it be rectified. Or is anyone else experiencing this highly annoying problem, or are the broadcasters to blame ???? I would appreciate some help before I melt it all down and make some great new sinkers for the fishing kit.............!!

Try a different receiver. The brand you have is known as the first to market but certainly not the best. It could be an antenna related signal quality issue too. Try searcvhing this forum with your STB model number abd see what otjhers have said.

G'day,
Your partly right on both counts.
It is possible for the broadcasters to have issues, although they obvioulsy endevour to not have any problems.
The second one, is that yes Set Top Boxes, and not just the dgtec's will drift with their lip sync.

My understanding of this is basically if there are two many errors in the stream sometimes they will go on the fritz...

You can try changing channels up & down - preferably even to another mux so not from one nine channel to another nine channel but from say nine to ten or vice versa.

If that doest work -> turn the whole box off - at the wall - or even unplug it.

After doing these things, when you go back to watch your program, it SHOULD be in sync

Hope this helps.

Sometimes the Digitec Box might have a slow milisecond delay in response to the picture. The easiest way to explain how to solve the problem is simply by quoting from one of the AV Receiver instruction manuals

"ADJUSTING THE AUDIO DELAY. When watching a DVD, HD decoder Box or other video source, the picture on the monitor may seem delayed with respect to the sound. In this case, adjust the audio delay to delay the sound and synchronize it with the picture. The audio delay setting is stored seperately for each input source."

The adjustment settings allow for a delay time of anything from 0ms-200ms.

See whether or not you have such a setting capablitiy in your plasma screen menu because it is a common problem for synchronization to be out on plasma screens.

What you have to understand is that it is not the video source that is the problem but it is the plasma screen. I have seen this lots of times as I own a hifi store and you are not alone with this problem.

*groan* Let me explain ......

All displays send out the picture at the speed of light (~300,000,000 metres/sec).
All speakers send out sounds at the speed of sound (~350 metres/sec).
So sound will be delayed by 3 milliseconds for each metre of viewing distance from the screen and speakers. Simple!

Inbuilt tv/plasma/lcd amps/speakers [might] have some delay built in for a 'typical' viewing distance, but a panel plus AVR needs to have the audio delay set in the AVR.

BTW, lip synch problems with the DGTec 2000A are common (I've had two of them in the past).

[quote=ijd,Mar 16 2005, 01:21 PM]
[quote=Shamus Soapbox,Mar 16 2005, 11:27 AM] The easiest way to explain how to solve the problem is simply by quoting from one of the AV Receiver instruction manuals 

"ADJUSTING THE AUDIO DELAY.  When watching a DVD, HD decoder Box or other video source, the picture on the monitor may seem delayed with respect to the sound.  In this case, adjust the audio delay to delay the sound and synchronize it with the picture.  The audio delay setting is stored seperately for each input source."  

The adjustment settings allow for a delay time of anything from 0ms-200ms.

See whether or not you have such a setting capablitiy in your plasma screen menu because it is a common problem for synchronization to be out on plasma screens.

What you have to understand is that it is not the video source that is the problem but it is the plasma screen.  I have seen this lots of times as I own a hifi store and you are not alone with this problem.



Hello Shamus,

I have the same problem of out of sync. I have an LG plasma screen and a TEAC STB. When I watch the program and use the internal speakers, no problem. When I take the audio feed direct from a source, be it DVD, STB or even the line out of the plasma itself and send it to a 5.1 system - it is out of sync.

Which brands of amps have digital delay on their inputs as I think it might be my only solution.

Thanx Tim

If you set the speaker distances correctly in the HT amp you won't have this problem.

BTW, it's NOT just a plasma problem ... it's a problem with ANY display device (LCD, PJ, CRT, etc) that is viewed from other than the default (usually ~3.0m) distance assumed by the audio amplifier (whether in the unit - as for TVs - or a separate amp). Different amps will have different default distances prior to end-user adjustment.

BTW, it's NOT just a plasma problem ... it's a problem with ANY display device (LCD, PJ, CRT, etc) that is viewed from other than the default (usually ~3.0m) distance assumed by the audio amplifier (whether in the unit - as for TVs - or a separate amp). Different amps will have different default distances prior to end-user adjustment.



When the Amp is on, along with the inbuilt speakers in the Plasma, the plasma sound is distinctly delayed by about half a second. The Amp sound is NOT in Sync with the picture where the plasma sound is. Also the viewing distance (around 3 metres) is the same as the CRT TV the Plasma replaced. There was not a sync problem then so I don't think it has much to do with the speed of light v sound.

The Sony Amp I have only lets you delay the centre and rear speakers as it assumes that the L&R speakers are at 'ground zero' and the other three are set up in relation to them.

As I cant delay the L&R they are in advance of the pic.

Any ideas anyone

Thanx Tim

Channel 10 (SD) is Sydney tonight seems to out of sync again. Also on the chroma on NCIS was high again!

Thank You All for your replies to my sufference. I would have to agree with the notion that it is NOT to do with the distance the plasma is being viewed at, as the delay in sync is, at times, extremely outstanding. I must say that I am extremely dissappointed with the result of my investment, given the advancements in technology, and the frequency with which I must put up with this problem.

(To all the guilty manufacturers and broadcasters out there,;- Syncronisation of sound with image is THE basic fundamental of "television" !!!!!!! ) If you cannot do this, then go sell newspapers on a street corner somewhere in Alaska.

Warren is saying his "audio is delayed" i.e. Plasma picture is in advance of audio


Shamus is saying picture is delayed, i.e. Audio in advance of video


Are you guys talking about same thing ? I think Warren, if u look carefully, the audio is infact ahead of the picture. Can you please confirm this?

I have a plasma and I when I watch channel 10 late news especially (SD), the picture lags the audio very obviously. (No, it has NOTHING to do with distance from screen). I mostly only watch AFL so of course, any delay is not noticed (no lip sync required).

My amp can delay the audio, so I'll pull out the manual this weekend and try a few delay settings. I haven't notice lip-sync problems with other shows like ABC Gardening show, ABC lateline etc. Some one else had a problem with channel 10 as well - Is this problem only apparant on Channel 10 ?

Steve, you are probably correct that my image is in delay to the sound, however, this is not just whilst viewing channel 10. It happens at least 50 - 60 % of the time whilst viewing fox digital through their box, or all free to air stations (2,7,9,10, SBS, etc.) through the DGTech 2000 HD STBox.

Even watching sport, where you cannot see the comentators lips, it is still off-puting when the sound of kicks, bounces, race crashes, etc, do not align with the vision.

Unfortunately, I do not have the provision for adjustment of the delay through my STBox, and anyway, shouldn't it all be idiot-proof, with standard default ratios, as in the good-ol-days of tube television. (Some of us don't want all the bells and whistles. We just want to switch the telly on, and see a nice clear HD picture, and crisp clear sound, both of which are in sync.). Is that asking for too much from a $7,000.00 set up ??

At this point I would like to state that I feel if manufacturers, broadcasters, and/or all those responsible for the whole digital television technology, continue to provide us with this sub-standard product and service, then it will become the accepted norm, and the standard of basic fundamentals of television will be lost forever.

Sorry, just having another dummy-spit.

Anyway, it appears I'm not the only one with this problem, and there seems to be a fair cross section of reasons for the miss-alignment, but does anyone have a hard-core solution?? I would be keen to hear from you. Thank you all for your time and advice.

Warren,

The best way to protect your $7,000 investment is to swap the Dodgytecs to Teac HD-STBs. For just $350 each you'll have far fewer lip-synch issues from poor reception, far better picture quality and a more reliable and feature-rich box (though the Dodgy is reliable IF you get a good one).

You might also consider paying a professional to measure your antenna reception and suggest improvements - since you should have no glitches at all with a good setup. (Well ... maybe only an impulse spike or two a week ... unless you're in a known black spot ;-).

ijd,

Thanks for the tip on changing the STB.

In suggesting the Teac, have you had a range of experience in this and other brands, or is the Teac just the one that you have at home ??

Also, what about the problem when viewing Foxtel Digital thru their converter(?) box ??

Perhaps the fact that the problem exists with both formats, may suggest that the problem is with the Hitachi 42PD-5000 Plasma screen ???

However, the fact that the problem does not happen 100% of the time, may suggest that the problem is with reception, but the antenna and cableing is new, and has the aditional signal booster in line.

I'd be keen to read your (and others) thoughts on these possible culprits.

Thank you so much.

ARghh I got a set top box today and the sound is out of sync by the tinyest amount but it is so anoyying, any new quick fixes any one has under thier belt?

Interesting quantification of delay/distance, Ian. I've never thought about it at these distances.

Some times ago I was told that the perception of lip sync problems start occurring when the audio is delayed by 4 frames (160 mS) with respect to vision, or when the audio leads the vision by as little as 1 frame (40 mS). Now I have not personally tested these figures, but it makes sense that it takes a longer audio delay to be perceived as we are all used to it in real life (the bloke chopping wood in the distance with the sound of the axe out of sync with the chop.
Recently I was compiling some clips (from various sources including DVD, VHS and betacams). The compile master was dubbed later to VHS and some of the clips appeared to have major lip sync errors, other clips none.

After a bit of examination it appeared that in the original compile the lip sync errors were within the window of human acceptability (and difficult to perceive), but when it was dubbed to VHS there was a slight misalignment of the record (or replay) VHS which made these slight errors appear outside the acceptability window.

Now 12 milliseconds (viewing distance of 3 metres) is not a lot of delay, but it may be just enough to move an already existing lip sync problem outside the imperceptibility window.
Of course it all changes when the audio leads the vision, something which is more likely with display devices which use frame buffers. In that case the audio delay from speakers to listener/viewer is working for us.

Cheers

JB

I have a Sony HD TV with a STB (brand??) and have the same problems with the audio not being in sync - it drives me crazy - I notice it most on Channel 10 but also on other channels. I have tried changing channels, turning off the STB, but it still happens.

It certainly isn't the viewing distance - we sit very close - and it happens whether I am using the internal TV speakers, or the surround sound speakers we have attached.

Your posts imply the problem is the STB but I feel like it happens (although is not as bad) when watching a DVD too!

Any suggestions?

Carol

DGTech HD STBs? Are they DGTec DH-2000A HD-STBs?
I started out with one of those had had exactly this problem.
The audio and video would drift out of sync. Usually after a period of time.
I never figured out why, I just assumed it was the box at fault.
Resetting the channel generally fixed it.

My DGtec was attached to the old standard 4:3 tv with audio through the stereo.
Eventually got a Topfield and have been happy ever since.
Perhaps its the STB?
JMO.

I have a cheap plasma $2500 made by Konka
I have noticed on channel ten that the audio is out of sync with the video only about 1 or 2 seconds, channel 9 seems very close to going out of sync but its not that bad.
I have just recently bought a DVD/Video player - when playing DVD the sync seems ok but when playing back video the sound is heared almost 2-3 seconds before the picture. Thought the problem was the DVD/Video player at first, but then tried the player on other Plasma's with same leads etc. with no problems. Tried a Video player which I brought with me from UK two years ago and that does the same as the DVD/Video player I have just bought.
My experience is that they are a lot plasma screens out there that can't handle a signal from the vhs tape causing it to go out of sync.
If you have any other solution to put this right please contact me.
Thanx.

My Pioneer set up is perfect ..never any lip-sync problems.Plasma /HD/ dvd/vcr all in sync .I read about this issue 2 years ago with the original plasmas . The new ones are ok .The Pioneer media box takes care of delays etc.Unfortunately there is a lot of dodgy gear on sale with no ethical standards imposed by ABA.

It seems to me that while you have two different boxes processing different parts of different signals (audio and video) you will always have the chance of this problem. Different vendors try differnet ways to make there box standout from the crowd (sometime it works, sometimes it doesn't). The audio vendor has their interest in providing the best dam audio they can, the display provider has to make the best "display" they can. The audio vendor can't dictate to the display vendor how they process and display their picture and vice versa, as they are working from two different points of view with two different signals.

It have and LG 50" HDTV and have no lipsync issues, but my HD STB is builtin to the TV.

If I play a DVD through the it and use both the TV and Hi-Fi speakers, you can hear a delay difference between the two even though both audio streams being fed by the same source (My HDTV via digital optic and HI-Fi via analogue audio).

Every device will have its own timebase as there is no signal that is sent to the AMP to say hear are the movements you must match and vice versa for the standalone display.

It seems that once you have it all in one box, Sound and TV come together as there would be a timebase signal in the DTV transmission that they can reference together( for those for don't know a timebase signal is like a heartbeart or drumbeat that everyone can hear, and you adjust yourself to it so you don't get out of step.) .

That is why all the latest amps and some STBs nowadays have audio delay adjustment. There is no otherway to compensate for this outside of having everything in the one box and having it fed via digital signals.

I think you will find that HDMI is one way that the vendors are looking at getting around this problem, keep the video and audio in digital together so everyone can march to the same drum.

Trev

I have exactly the same unit; but I get lip-sync problems all the time on some channels. I suspect it's a signal strength issue (though the unit reports 85% signal strength).

I do agree it's extremely disappointing. Digital technology should FIX problems, not introduce them!

I have a Hitachi J35 STB feeding a 68 cm HMV CRT TV through the TV’s SCART connection. If its a good sound track I also take an Audio feed through my Kenwood Hi Fi.
Most of the time (nights) there is no problem but at other times the sync is so bad I go back to Analogue.
As for the viewing distance I have found it makes no discernable difference, We can watch TV from the dining room table which is around 7 to 8 M away or the lounge which is around 3 to 4 m away and there is no difference. Likewise there is no difference between the speaker output from the TV or HI FI, the difference is between the combined audio and the video signals on the other hand. I am really annoyed when after shelling out around $1,400 for new aerial, lead-ins and STB etc that I have this amongst other problems.
I will try turning the STB off at the wall socket and see what this does but as far as adjustments of the delay are concerned, I am unaware that I have any.
I feel that the technology is immature and should not have been let loose on the public, let alone promoted till it was mature.
In the past Australia has lagged behind other countries in introducing new technology, for instance I believe we lagged around 30 years on B&W TV and around 15 years on colour. This was done for two reasons:
1.
To let everyone else make the mistakes and we learnt from them before going down the same path.
2.
To give our local industry a boost when sales, Profits and employment etc were sagging.

Since no one gives a fig about 2. any more and we no longer have any industry left to speak of it leaves 1. to consider.
We no longer have any wisdom left in our parliaments with a corresponding downgrading and politicising of the public service the result has been we now have a technology introduced before the rest of the world has made the blunders and we have had a chance to learn from them.
What else can you expect?
The fact that we have to put up with such nonsense and require forums like this to seek advice and vent our anger is deplorable. Since when did rocket science become part and parcel of what should be ordinary household appliances that you should be able to just plug in and enjoy?

The problem doesn't lie with the digital transmission system as such. DVB goes to great lengths to ensure that the audio and video remain as in-sync as they were when they were fed into the encoders back at the TV network end with more time stamping than you can poke a stick at.

Putting stuff-ups by the networks aside, audio / video sync problems are 99% caused by the viewers equipment. I remember reading a service bulletin for a certain well known brand of display regarding audio sync complaints from owners not too long ago. It seemed that the firmware in the display (de-interlacing etc) was causing a potential 100ms delay between video going in and it actually being visible on the screen. The solution was to take the set to a service centre and get the firmware upgraded to a release that reduced the delay to 40ms (thats still 1 frame time).

The sync problem can become more uncontrollable when you use the digital audio output of a STB too. Using the STB's analogue outputs guarantees that the video and audio are synced (well it should, except as I've noted below). If they are fed into plain and simple analogue amps and TVs with no digital tricks, you'll see/hear good sync. When using a digital audio output the delay through your digital input amp may be a known quantity, the amp itself has no way at all to tell how much of a delay your display introduces and thats where things can go off the tracks. Some displays don't even have a constant delay through them - switch channels and you have a 30ms delay, switch again and you get a 100ms delay, switch back and you don't go back to 30ms delay. Good displays (price is not necessarily an indicator of goodness) keep the delay through deinterlacers etc to around 20ms - half a frame time. It can be all very frustrating.

Finally, I have come across some name brand STBs that really do randomly output audio and video out of sync. There really is no excuse for this and the STB makers know it. In each case I've found of this, a firmware update has fixed the problem. Good luck getting this issue with a generic box fixed.

These types of problems are observed world wide (fortunately they don't seem to affect a lot of people, either that, or most people just can't pick the slight desyncs) and aren't likely to be fixed easily and aren't really a problem caused by our DVB-t system.

I don't get problems like this, because the digital signal goes into my TEAC ITV-D500, then the audio goes digitally to my 5.1ch surround sound system as well as the plasma, and the video obviously goes to the plasma and then from plasma to surround sound system, for me it doesn't matter which path I send the audio, I don't get lip-sync problems, except for last night on big brother up-late, but it was network related because I get SC10 and another person on here said that they had the same problem on TDT.

Has anyone noticed audio - video sync problems with SBS recently (last couple of nights)?

Particularly in northern TAS?

I find my STB occasionly gets video and audio out of sync, and it isnt the relative slowness of sound versus light propogation in the lounge room. Fortunately a hard reset fixes it!

Generally I turn our (relatively) new Healing STB box off completely when we are not using it, not just down to standby, otherwise it sort of 'squeels' A side effect of that is that it rarely goes of sync.

The Wintal I used to have also occasionly went out of sync, and a hard reset was the simple workaround there too.

I have an Hitachi 8800, LGSTB, and pioneer 530DVR. If I take 1 audio out from the STB, run it through the DVR then into the TV audio component input, then send another conection from the STB straight to the analogue amp we get perfect sync. But when we play DVDs the TV and amp are out to much to be able to bare. It is alot of fuss this!

Ihave a new LG 32FS4D with built in HDTV receiver and am experiencing similar problems to other posters with sound and picture out of synch. I find this is more pronounced on HD channels than on SD channels. I have excellent signal strength on all channels. Any ideas

Which City are you in and which channels are the worst ?

rgds Damon

It is the set.

Connecting an external HD STB does not show the same issue.

===============
Back in April I wrote:
The fact that we have to put up with such nonsense and require forums like this to seek advice and vent our anger is deplorable. Since when did rocket science become part and parcel of what should be ordinary household appliances that you should be able to just plug in and enjoy?

I am still of the same view.

I have been told to go get professional advice and even denigrated for my efforts, It is often easy to give advice, but that advice is not worth a fig if the person giving it has not seen the problem first hand.

The reality is that we live in an area of Sydney where the BER and Signal varies as a result of over flying aircraft (Low) and even the amount of foliage on the trees (seasons), whether the leaves are wet or dry or still as opposed to blowing in the wind. Short of putting up a ridiculously high mast, Having a community mast and aerial erected or moving, I don’t see any other alternative.

When we have signal problems I simply go back to Analogue and everything is sweetness and light as the Analogue signal and receiver is far more forgiving. We also have problems with the power so I have installed an “Uninterruptible Power Supply (UPS) on the Audio Visual equipment. This has made a big difference to the operation of the STB. Even with a surge suppressor you would get a momentary loss of audio or the picture would Pixilate as major appliances such as the Air Conditioner turned on or off or there was a momentary voltage drop or surge in the Mains. But again this did not affect the Analogue signal only the Digital one.

As for out of sync sound I have found that if I re-boot the STB, it in most cases fixes the problem.

You fork out a small fortune for a quality STB so you don’t have problems like this but you still have the problems. Even after having the firmware upgraded to the latest version. There has to be something badly wrong here. Especially when you see cheap ST Boxes giving less trouble, and producing a better and more consistent picture.

I have found however that my computer and "Videomate" Video card does not have the same amount of problems, or should I qualify that by saying the problems are not as bad or as often.
But then with a dual core 64 bit 4 gig Athlon chip in it plus 4 gig of RAM you would hope not. With that amount of raw computing power something should work. But just the same I went through three video cards before I settled on this one, the other two being not up to scratch.

It is still my belief that this is an immature technology and should have not been foisted on to the public until most of these wrinkles were sorted out.

Next time you have a problem try rebooting your receiver and see if this helps.

Regards
Dock.

hi sorry all I am also new to this forum so if i have added this question in the wrong spot please let me know.

my LG tv has frozen i have sound but the picture is frozen. can anyone suggest some thing that i can do.

I have turned the TV off and on but still the same thing it wont let me change the channel or switch the tv off from the remote

Hi, I have a the same problem with a lg plasma'. Channel nine in Melbourne Aus. indicate that the problem is caused by atmosheric conditions. Has any body else heard of this condition? REG.

i get the freezes too. only on channel 90 in the evening aroun 8-9pm. I am told the tv reboots after a few hours & this seems to solve the problem, but it does suck a great deal!!!
i would love to know how to force the reboot.

Thanks for the info. I too have an LG 42 Plasma with exactly the same problem (frozen picture, but sound) - Channel 9 certainly appears to be the culprit with sending the thing nuts. Any info to manually reboot this system would be much appreciated. I was pretty close to calling a service person out.

Too bad LG doesn't list what seems to be a common problem in their troubleshooting guide!

Thanks again,

Luke.

recently worked out how to get around this. I am told it is the way ch9 sends its transmission & it lock the tvs.
to get around it, unplug the antenna, turn on the tv & it wont be able to find the cahnnel. when this happens, you can change the channel. plug the antenna back in & away you go. most times ch9 will still lock it up so you have to avoid ch9 for a few hours.

Thanks for the added info cqae!

And as you suggested, it appears as though the unit has rebooted during the night and was fine again this morning. It has done this sort of thing before, but not as badly as the last time. I'm almost positive when I think back that it was always channel 9 that seemed to start it off. Funnily enough between the hours of 8 and 9pm.

I too apologize if this is being posted in the wrong spot in regards to the main jist of the thread. I hunted the web and found this particular site had the answers to the exact question I was looking for.

Thanks again & cheers,

Luke