1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Lip Sync

Discussion in 'Plasma TVs' started by JamesAldridge99, Dec 16, 2002.

  1. JamesAldridge99

    JamesAldridge99
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Hi,

    I recently bought a Panasonic PWD5 Plasma screen and I have an annoying problem. I have the screen connected via component output from my DVD player but there seems to be quite a delay somewhere causing lip sync problems. Does anyone know if I'm doing something wrong? I hope this is not normal, I couldnt put up with this. Please help.

    Thanx
     
  2. nickt

    nickt
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    If you search on this forum there are a couple of threads on this issue. Basically down to the video processing on the plasma taking longer than the audio procession in your AV amp.

    Nick
     
  3. cadmeister

    cadmeister
    Standard Member

    Joined:
    Nov 12, 2002
    Messages:
    107
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    19
    Location:
    Milton Keynes, UK
    Ratings:
    +0
    James,

    I won't repeat the large amount of detail that can be found in other threads, but I will say that there are a number of factors involved here including:

    - the ~80ms delay the screen introduces
    - the quality of the DVD or broadcast you watch
    - whether your amp can adjust/delay the audio
    - generally your sensitivity of lip synch (some people are amazingly unphased by it)

    Personally I am OK with DVDs (since moving from composite to component) and just about OK with the issue on most terrestial channels via SKY (1 thru 4), but almost all other SKY stations (E4, ITV2, Scifi etc) start to get that badly-dubbed-kung-fu-movie look to them.

    I was shocked that this issue isn't more often pointed out by reviewers. Maybe the tuner boxes help or the more sophisticated amps appearing on the market accomodate for this.

    Someone once told me it was the price you pay for being on the leading edge, but frankly I already thought I paid enough of a price :eek:
     
  4. Jon Weaver

    Jon Weaver
    Well-known Member

    Joined:
    Aug 16, 2000
    Messages:
    6,002
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Location:
    Born in Bristol but now in Newport, (for my sins)
    Ratings:
    +639
    One thing I am not sure about is whether this is any worse when using 'Progressive Scan'.

    Everytime I have seen this mention, its always by someone saying that they see it when using 'Progressive Scan'

    But, from what I understand about the problem, the 'lip sync' delay would be constant, not matter what the source.

    Infact, that fact that that plasma does an internal Interlaced-PS conversion, makes me think that this should be worse when feeding the screen an 'interlaced' signal.

    I only feed mine with one cable/converter, but from 2 devices.. Sky and DVD.. Both via a JS RGB-VGA converter.

    Appart from the obvious times when Sky is out, if I look VERY hard at a 'normal' Sky signal, I can just about detect a lip-sync delay.

    But on DVD, I can safely say I have never noticed ANY problem.

    Will going down the PS route (which I plan to do once PAL PS players are common), will this make the Lip-Sync problem worse?
     
  5. CarlB

    CarlB
    Active Member

    Joined:
    Jan 8, 2001
    Messages:
    1,096
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Godmanchester, Cambs
    Ratings:
    +83
    As has been mentioned there is already much detail in other threads on this forum on the issue. I noticed terrible lip sync issues when feeding my Panasonic plasma with an interlaced DVD signal via component input. I since upgraded to a Denon 3800 and when feeding native 480p to the panel via the Denon's progressive output I no longer see any lip sync issues. I suspect the Denon allows the delay to audio while it deinterlaces the signal, whereas the plasma does not.
     
  6. Philipsguy

    Philipsguy
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Can one use the general delay functions in the amp to solve this kind of issue?
     
  7. CarlB

    CarlB
    Active Member

    Joined:
    Jan 8, 2001
    Messages:
    1,096
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Godmanchester, Cambs
    Ratings:
    +83
    The normal channel delays do not usually have enough range, offering up to 20ms delay on average (60-100ms required).
     
  8. cadmeister

    cadmeister
    Standard Member

    Joined:
    Nov 12, 2002
    Messages:
    107
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    19
    Location:
    Milton Keynes, UK
    Ratings:
    +0
    My theory would be that Prog Scan presents the image in a 'ready to use' format for the plasma and therefore the delay in presenting the image should be reduced, however there is still a delay in putting the digital image together so a small delay would be present for both interlaced and PS images.

    Mid range amps and below only offer a small delay (5-20ms) for the audio to cope with speaker placement. I reckon that making an image so big and typically so vibrant accentuates your attention to the image and therefore you notice lip synch more.

    As I have said previously, the single biggest factor is personal sensitivity. My worst DVD is R2 Shrek and I've sat people through it who can't see my issue whilst I wince at every dialogue!
     
  9. CarlB

    CarlB
    Active Member

    Joined:
    Jan 8, 2001
    Messages:
    1,096
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    51
    Location:
    Godmanchester, Cambs
    Ratings:
    +83
    This is why I keep harping on about driving the plasma at native rate resolution. My progressive output from the Denon 3800 requires no additional processing by my Panasonic SD display so I have seen *no* recurrence of lip sync issues since I bought the Denon.

    If you are using a higher resolution display you are still not driving the panel at native 480p resolution so some additional scaling will be required of the image, which is probably enough to reintroduce lip sync issues.

    PS. I think Shrek is just a disc with major issues on the lip sync front, even watching it on my CRT and with an interlaced output produces rubbish lip sync.
     
  10. r22flyer

    r22flyer
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I raised this issue when I first got my plasma in September... so here's an update on my experiences...

    I solved the analogue sound problem by inserting a delay unit in the audio feed to the AV amp (delay unit is a TC Electronic M-One £270)

    'Normal' TV like a Pace DBTV box or a Sky box generally need a delay of around 80mS for accurate lip sync.... I find some channels worse than others so I occasionally have to adjust my delay unit to suit - however it mainly stays at 80mS

    I have viewed quite a few DVD movies with my new Pioneer 656 player over the Xmas hols listening to digital 5.1/DTS audio via the optical (not delayed) input and found that I don't notice lip sync problems on movies (even though I'm very sensitive to it)... experience has shown that DVDs are not always perfectly lip synced anyway and this effect could be compensating...

    Music DVDs are a different ball game - some are OK and in sync (mainly region 1 discs) but most are way out (mainly region 2 discs)... I HAVE to view R2s using delayed analogue sound.

    For anyone interested, you can view my connection diagram at www.projectsys.demon.co.uk/plasmawiring.jpg

    As an aside I'm waiting for delivery of the new Keene Quattro Scart switch box so I can eliminate the manual audio switch box and switch all my scart sources through 1 input on the plasma

    Overall I'm ultra pleased with the results...
     
  11. BigH

    BigH
    Active Member

    Joined:
    Dec 26, 2002
    Messages:
    447
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Hampshire
    Ratings:
    +8
    Hi,

    I just taken delivery of the 50" panny (PW5) and initially I fed it composite and S Video signals - I was awaiting delivery of a JS RGB-Component box at the time and had no choice. I too noticed lip sync problems, especially lousy Sky digital stuff. The main channels, BBC etc where not so bad but there was some delay. Having received the JS box today there was the obvious picture improvement, I also noticed that the lip sync was better!! DVD play back was fine so far, at least from a lip sync point of view, so far I have only tried The Green Mile and the The Matrix, time will tell!!

    However I have noticed something else, instances of screen break up during some periods of extreme video change ie fast motion combined major light changes, one of the execution sequences in the Greem Mile showed several seconds of Video break up. Has anyone seen this before? Interestingly I did not see this before I hooked the system up through the JS box, I might add that I had also not extensively tested for it either. I will give a go when time permits.

    Apart from that the images are superb despite the sources not being the highest calibre.

    System is currently as follows:

    Panasonic TH-50PHW5
    Pioneer DVD DV 636
    Panasonic Sky digital box (TU-DSB30)
    Panasonic SVHS video NV-HS980B
    Sony STR-DB940
    Kef 2005

    Hooked up as follows:

    Sky>scart RGB to DVD (loopthrough)> scart to JS RGB/component>RCA cables to panel
    VCR >S Video to panel

    Has anyone noticed improvements or otherwise if using the Tuner option?

    Any feedback for system improvements would be appreciated.

    Regards,
     
  12. r22flyer

    r22flyer
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Big H,

    I too have a JS component convertor and your problem may be similar to my image tearing problem on bright white scenes....

    Have a look at www.projectsys.demon.co.uk/tearing.jpg

    The image breaks away at the top right...

    I have worked with JS to solve this but its not perfect just yet...

    Let me know if this is a similar problem and also possibly search out my other thread re this problem (search on r22flyer and you will find it easily)....

    Big H - I notice you have a Pioneer DVD player - I have the Pioneer 656, what a coincidence... go into the DVD menu and edit the output settings to ease the problem [reduce the contrast setting by one or two marks]
     
  13. BigH

    BigH
    Active Member

    Joined:
    Dec 26, 2002
    Messages:
    447
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Hampshire
    Ratings:
    +8
    Hi r22flyer.

    I saw your thread after I posted on this one!!

    I had a look at the screen shot, it is not the same as what I have seen, basically the picture breaks up momentarily, difficult to cabture as it happens so fast!

    How easy is it to measure the RGB output waveform?

    I have a 60 Mhz scope would that be of any use?

    I will do some more testing tommorrow and post and any new findings.

    Regards,
     
  14. r22flyer

    r22flyer
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Hi BigH,

    My web pic is actually a freeze frame from the Stargate film DVD where RAs spaceship blows up.... I paused playback and advanced frame by frame until I reached the bright image (with breakup) and took a digi photo...

    If you actually run the DVD at normally speed it appears as picture breakup and/or the image 'bouncing' vertically momentarily... try pausing your DVD at the offending point....

    I still have the emails from John Sim if you want to do the measurements and let us all know what you find... private mail me at avf@projectsys.demon.co.uk if necessary....

    Regards,
    Paul
     
  15. BigH

    BigH
    Active Member

    Joined:
    Dec 26, 2002
    Messages:
    447
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Hampshire
    Ratings:
    +8
    Hi Paul,

    I tried the freeze frame mode, unfortunatley the picture breakup happens between frames as a transient flicker even when stepping through on freeze frame, however it only happens going forward, if I step backwards its OK!! Bright frame to darker frame gives break up, going back the other way is OK. The problem may not be the same as you are experiencing

    I also took a composite video out from the DVD and connected it directly to the panel, no problems at all, apart from a poorer picture. I've yet to try the RGBS direct from the DVD to panel, still working on the cable!

    Regards,
     
  16. r22flyer

    r22flyer
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Thanks for checking BigH

    It still is probably the same high signal level fault but only marginal....

    Did you try knocking the contrast setting down a notch or 2.....

    Or conversely increase it a notch or 2 to see if you make the problem worse... just for proving....

    JS sent me a mod (shorting out a coupling cap) which did make a significant improvement for me so this mod alone might solve your problem entirely....

    Cheers
    Paul
     
  17. BigH

    BigH
    Active Member

    Joined:
    Dec 26, 2002
    Messages:
    447
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Hampshire
    Ratings:
    +8
    Paul,

    can you send details of the mod in a PM and I will give it a go.

    Regards,
     
  18. BigH

    BigH
    Active Member

    Joined:
    Dec 26, 2002
    Messages:
    447
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    Hampshire
    Ratings:
    +8
    r22flyer,


    I tried fiddling with the contrast, it made no difference. I'll try the suggested modb and see what that does.

    REgards,
     

Share This Page

Loading...