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Sguest
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LIP SYNC ISSUES!!

I switched from sky to virgin last Friday, but have problems with lip sync on some channels. Some channels are fine but some are quite far out. Have tried disconnecting soundbar but this hasn't fixed the problem. Can't narrow it down to HD or none HD either as it does it on both but not on all channels!!

Other than that and getting to grips with the menu it's fine.

How do we get this fixed? Do I need to get an engineer out? Pls let me know

Thanks
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backtothefuture
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Message 2 of 8
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Re: LIP SYNC ISSUES!!

I can't say I've experienced this with Virgin myself, but have with Sky on numerous occasions.

With that I just reset the box.  Maybe this is worth a try with your TiVo box ?

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Re: LIP SYNC ISSUES!!

Hiya, have done a reboot and didnt fix it but thanks
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nexsen
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Re: LIP SYNC ISSUES!!

What type of TV do you have?  If it allows changing the audio delay (like Samsung and Vizio do) I may have some things to try:

Set the delay to zero and see if it helps.  Then add delay in the smallest steps and see if it improves or gets worse. SInce Samsung's delay steps are 10 ms and Vizio's are 20 ms you probably won't ever feel it is perfect.

I use a Felston DD740 which almost always lets me correct lip-sync perfectly but there are occasions when the audio arrives already delayed more than my Samusng's video delay (about 70 ms) and even with the DD740 set to zero it's still off.  Luckily that's rare but does happen.

You really need 1 ms adjustment get it prefect. Some people apparently need 1/3 ms steps since that's an option on the DD740 but 1 ms is all I've ever needed.

But if you have a Sony, Panasonic or Toshiba they unfortuantely add an audio delay to cancel the video delay of the screen but don't allow the user to change it or turn it off so you won't have the negative adjustment range (your TV's video delay) available to correct for arriving audio delay.

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nexsen
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Re: LIP SYNC ISSUES!!

I forgot to mention: If you have one of those TV's that add audio delay and don't give you an option to change it you can take s/pdif audio from each source directly to an AV receiver or sound bar and eliminate the delay your TV imposes but unless you insert a digital audio delay (like my Felston DD740 or similar units made by Alchemy 2 and Primare for lip-sync correction) in that path your TV's video delay will more than likely make the programs that previously seemed alright seem out of sync since the audio will be 60 to 100 ms "earlier".
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Forum Team
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Re: LIP SYNC ISSUES!!

Hi Sguest

 

Welcome to the Community, I'm sorry for the problems you're experiencing with the sound on your TV service recently. 

 

Nexsen has made some brilliant suggestions, as a lot of TVs come with audio delay settings. Although as you're only experiencing this with some channels it might not resolve the issue entirely.

 

I've located your account to run some tests on the set top box and we're not detecting any errors from our end at the moment. Are you experiencing this issue with more than one set top box if you're using more than one? 

 

Look forward to hearing from you

Craig


New around here? To find out more about the Community check out our Getting Started guide


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nexsen
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Re: LIP SYNC ISSUES!!

Craig is certainly right! If you succeed in correcting lip-sync on a channel that is out of sync by turning off your TV's internal audio delay (if your TV allows that) it means that channell's audio was arriving already delayed and you corrected it by adding your TV's internal video delay to offset it but when you change back to a channel whose audio is NOT arriving delayed the audio will be well ahead of the video and perhaps even more noticeable than the lip-sync error you corrected initially on the other channel.

What most people (even some experienced TV technicians) don't acknowledge is that audio and video are almost never in perfect sync. Its just usually "close enough" that our defense mechanism of looking askance - away from the lips - allows us to ignore it. It isn't even guaranteed to be perfect when the content was originally created and certainly not after many digital video effects have been applied - all of which have the potential to in inject lip-sync error.

Although the problem "can be" channel related it often is in the programme itself. I've even seen DVD's mastered with significant lip-sync error. Denzel Washington's INSIDE MAN for example had about 40 ms delayed audio which is the opposite direction of most lip-sync error.

The wide swing in lip-sync error from channel to channell and even programme to programme is why all the lip-sync correction devices made by companies like Alchemy2, Felston, Primare, etc. have hand held remotes that allow shifting audio in 1 ms increments without disturbing the talking head "targets" on screen you are adjusting the audio to match.

Most of them also have preset delays you can recall with a single button in cases where you find a fixed offset between channels or make note of delays for specific programmes if you find they remain the same from day to day.

Personally I don't use presets although my DD740 has 36 (9 per input) as it also has numeric entry and I find it easier to recall the delay needed than to remember which preset register I stored that delay in.

The remotes on these units make it feasible to correct lip-sync without plastering menus all over the screen. You MUST be able to watch the lips as you shift audio and many AV receivers that claim a lip-sync featrure and offer an audio delay clearly don't understand this as they cover the screen with menus when changing the audio delay. They apparently think a fixed delay can correct lip-sync and it definitely cannot as lip-sync error changes from programme to programme as well as source to source and channel to channell.

Broadcasters focus on keeping (or trying to keep as it were) lip-sync error small enough most people don't consciously notice it (below about 42 ms) but research at Stanford statistically proved it causes a negative impact on viewer perception even when not consciously noticed.
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nexsen
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Re: LIP SYNC ISSUES!!

If you are interested in that research from Stanford Google "Reeves and Voelker Audio Asynchrony" and I am sure you will find a link as it is often quoted. Companies have even sprung up to align audio perfectly for court cases where videos are used since lip-sync error makes the video testimony less believable.

The Stanford research statistically proved lip-sync error causes similar feelings about the characters as we have about people who don't make eye contact with us even though "we" are the ones looking askance when lip-sync is off. (They used adjectives describing the characters as more agitated, less persuasive, less successful, etc.)

From that research it appears as we viewers subliminally look away from the lips to avoid the impossibility of sound before the action that created the sound we are left with the impression the characters are not making eye contact with us even though it is the viewer who is not making eye contact.
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