Lip sync error Plasma and LCD TV's

Forums › Home Theatre (including HTPC and EPG Collector) › Lip sync error Plasma and LCD TV's

bbjnz

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#19929 6-Mar-2008 19:43

I have recently bought a 42 inch plasma and we are experiancing lip sync error especialy via Sky. I have read this is a common problem and there are people selling boxes for $400 to fix it. I can not believe that a product can be sold that has a built in error like this. I am interested in comments and or fixes for this problem.

A good article confirming the problem can be found at:

http://bbs.thenet.gen.nz:8081/$WEBMSG.Read.R-FTV.989

cyril7

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#115051 6-Mar-2008 20:32

what panel is it, try turning off some if not all of the fancy digital processing features. I should point out the problem is with the panel not sky. Many digital panels have quite high levels of digital processing for deinterlacing and scaling, depending on how its done this type of issue can crop up.

Cyril

bbjnz

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#115054 6-Mar-2008 20:46

Hi Cyril

Good to hear from you again.

It is a cheap HPC TV. I know why it was cheap now. The picture quality varies considerably from diferent sources.

I am not sure what you mean by

"turning off some if not all of the fancy digital processing features"

Can you tell me more please.

BBJ

n00dy

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#115055 6-Mar-2008 20:46

we just switch sky chanels then back again and the problem goesv away. more sky than tv

bbjnz

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#115058 6-Mar-2008 21:02

Yes it mainly Sky and you are right it does come and go so must be when we switch channels. Thanks for suggestion.

tchart

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#115109 7-Mar-2008 08:28

Hi

Cant say ive noticed any lip sync problems on my setup.

Ive got a 32 inch RCA LCD (from the Warehouse!). Ive got Sky hooked up through a SCART to Component adaptor (from DSE). The picture is brilliant especially on TV2/3.

I have noticed that before Sky upgraded the set top box firmware to have Component output that the picture on either S-Video or Composite was slightly delayed.

Try this;

- Press the ? button on the remote (or bring up the EPG)
- Scroll quickly through the channels using the up/down buttons on the remote

When I do this and the signals either S-Video or Composite the text is a bit blurry and takes a few seconds to "crisp". This does not happen on my TV when its hooked up using Component. Maybe its the response time of my TV? I think its 8ms (or is it 16ms?) but its not an issue with the Component signal.

Anyway, its worth getting a SCART/Componet adaptor for the better picture.

And like Cyril said, turn off all the "features" such as noise reduction, cinema mode etc. I find I get a much better picture if all of this junk is turned off.

Trevor

tchart

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#115110 7-Mar-2008 08:33

Oh and another thing (just to confiorm how cheap I am) I have an S&V DVD player from Countdown.

Paid $99 for it and its got HDMI with upscaling to 1080p (it also plays DIVX). No lip sync problems with this except on some DIVX movies (which is probably just becuase of the nature of the format).

If youve only got one Component input (like on my TV) I had to get an HDMI player to free up the Component for Sky (and playing DVD's on S-Video is just crap).

Its probably the best player Ive ever bought.

Trevor

PS Mind you the only player thats ever lasted a really long time is my $500 TEAC I bought in 2000! The thing is built like a tank.

cyril7

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#115118 7-Mar-2008 08:57

Sorry I read or misread from the original post that lip sync was on all channels and related to the purchase of a new digital screen which due to inherent deinterlacing processing are more prone to lipsync issues.

DVB systems (including sky) use a PCR sub stream (Program Clock Reference) to assist the decoder to time the video and audio together. Sometimes the wheels seem to fall of this process and changing channels reloads all required streams for the channels and puts things back in order.

I must admit that I have not seen occasional lipsync issues on sky for a long long time, it used to occur occasionally and changing channels away and back always got things sorted, that said we have a newer box now and Sky have had several changes in firmware that may have sorted any occasional drift issues.

It may be simply an issue that you have now introduced an extra delay with the new panel, and the occasional slight misalgnment in the decoder now appears more obvious when it happens, previously it may have been misaligning from time to time, but not to be noticable.

Cyril

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Regs

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#115143 7-Mar-2008 10:50

i have a samsung plasma screen ps42s4s which has lip sync issues, but only if i use the passthrough audio out from the screen and into home theatre amp. If i use the builtin speakers then the sound is in sync. samsung made a "mistake" in that panel in delivering the passthrough sound unaltered while doing all the processing on the picture - if i played sky (or other crappy video source) i got really bad problems. If I used a DVD player hooked up via DVI and sent the picture in the correct resolution to the screen (upscaling dvd player) then the audio was typically fine as the screen did not have to mess with the picture, just display it.

Samsung sent me a kit that I could use to rewire the speaker output to RCA plugs which fixed the problem, but it wouldnt have been optimal as the audio from dvds would also get screwed with going through the internal speakers.... a better solution would have been an audio delay introduction.

My solution was to move to a PVR (windows media center) and that does all the video and sound processing passing it to the screen and the home theater amp. because the sky/tv signal was being processed in the PVR and delivered to the screen in the screen native resolution the screen had no post processing on the picture and therefore the delay was gone.

i'm not sure if samsung have changed this in subsequent models - i expect that they would have at least looked at it.

Regan

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richms

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#115215 7-Mar-2008 14:33

Turn off anything to do with noise reduction, digital comb filter, and any other processing in the menus and it should reduce the latency.

I cant see how people can use screens via composite for gaming with that lag. I was playing on a mates xbox on a plasma and I totally sucked and was blaming the controller. On a CRT - no worries at all with the same xbox.

Richard rich.ms

bbjnz

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#115615 9-Mar-2008 21:21

Thanks for all the information. The error seemd to only happen now every now and then and switching Sky channels seems to fix it.

One more thing. I got a scart to component adaptor and a RBG compenent cable which I thought was the correct cable from DSE (that was all they had). The panel has a Y Pr Pb input. Are RBG and Y Pr Pb interchangble. I have tried to reseasrch and some say they are and some suggest they are not. Anyway I can not get it to work through the input terminal on the panel.

richms

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#115730 10-Mar-2008 13:44

The adaptors are interchangable but you will have to set the sky box to component via scart first so that it will output component, the rgb out will get nothing when put into component since there are no sync signals on it.

Richard rich.ms

bbjnz

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#115813 10-Mar-2008 18:46

Thanks for the information. I have a very old decoder and it doesn't give me the option of component. I have a newer decoder in the rumpus room and it does give the option. I haven't swapped yet but one thing I don't understand is where does the panel get audio from using component. I understood that it uses the A/V left and right plugs but the newer decoder has no output other than scart.

Oh so much to learn.

cyril7

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#115821 10-Mar-2008 19:20

Presumably your newer decode is the small silver Pace DS-230, yes you will need a SCART cable that also has audio connections, or there is a 3.5mm headphone type socket, this will give you line level audio out so you will need a 3.5mm stereo cable to RCA for audio. Otherwise Jaycar WQ7255 will give you both component video and audio from the TV SCART

This 3.5m socket on the DS-230 also theoretcially supports optical spdif, there is a MiniDisc convention for spdif via 3.5mm headphone sockets you can get 3.5mm to TOSLink cables and adpators, unfortunately the current Sky standard firmware does not support spdif or DD at all, so dont get too excited, however the hardware is there should Sky eventually get their act together on this matter.

Cyril

bbjnz

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#115830 10-Mar-2008 19:42

Thanks Cyril

I will do some experimenting