1. Join Now

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

scrolling credits

Discussion in 'Plasma TVs' started by philsparks, Feb 25, 2004.

  1. philsparks

    philsparks
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I was just loitering in the local comet as I've been thinking for a while of getting a new LCD TV. Narrowed the choices down to either the Philips or soon to be released JVC (with a slight preference for the JVC as it's not as wide).

    While in currys the credits at the end of the programme arrived, they zoomed along the bottom of the screen and I'm not exagerating when I say that on every single LCD TV they were unwatchable, smearing into an indeciferable mush. However on the rows of £100 - £300 CRTs they were fine.

    Now if I'd just blown £1k or more on the latest LCD TV I'd be pretty annoyed with performance so bad.

    All the TVs were in-sync so they must have all had an analogue RF feed (no freeview). The aerial signal was obviously pretty poor judging by the picture quality.

    I've noticed before that rolling credits is a quick indication as to how sluggish a plasma/LCD TV/Projector is but thought that the latest generation would be better (Comet had the 23" Philips and the 26" JVC - and they were as bad as the rest).

    If I do go for a LCD TV can anyone reassure me that with a better aerial signal the quality will improve or is this simply a failing of the current technology?

    Phil
     
  2. richard plumb

    richard plumb
    Well-known Member

    Joined:
    Jan 27, 2002
    Messages:
    14,271
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Location:
    Windsor
    Ratings:
    +1,015
    Current technology. Mostly down to response time. However, most LCD TVs (if not all) have a response time of 16ms, which should be enough for 60Hz update. Maybe they don't like 50Hz.

    To be honest, I've noticed this on my TV, but its only really a problem on fast horizontally scrolling titles. And considering the general picture quality, I'm not going to get upset about blurry credits. I see no other problems with it, unlike with some CRTs. Don't even see a problem on football or tennis.

    If you are willing to wait a little longer, Philips new range of LCD TVs will have a response time of 12ms, so should have much better handling of fast movement like this.
     
  3. johndon

    johndon
    Active Member

    Joined:
    Feb 3, 2002
    Messages:
    1,924
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    48
    Ratings:
    +88
    The smearing of horizontal scrolling text also happens on RPTV's (at least it used to on my 40" Tosh) and, to a lesser extent, on my current Hitachi 42PD3000 although it never seemed to affect vertical scrolling credits. It never seemed to affect fast moving objects in general, just scrolling text.

    Doesn't bother me though as I don't watch the credits!

    John
     
  4. tartan_guru

    tartan_guru
    Member

    Joined:
    Nov 17, 2003
    Messages:
    154
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    London
    Ratings:
    +17
    Phil,

    I have a 17" philips LCD screen and have seen the effect that you speak of. However alot of this smearing is often due to the noise reduction and other picture processing employed on most of these screens, turning this off (it's called 'active control' on my set) eliminates most of these issues. This problem is not only unique to LCD's, I have also seen the same effects on plasmas and 100Hz CRT's. I suspect that the situation was certainly not helped by the usual Currys poor RF signal, as the noise reduction was probably trying to work at full strength!
    It is also worth bearing in mind that the other major cause of this smearing is due to the de-interlacing in the set which is a problem shared by both plasmas and lcds. I experience almost no smearing on film sources (as these originate from a progressive sources), but i do get some smearing on video derived sources. Often this is a result of the screen dropping into the wrong de-intelacing mode (e.g thinking that it is a film source rather than video).
     
  5. philsparks

    philsparks
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Thanks for the bundle of replies. I think tartan_guru is right in that it's the electronics rather than the screen that's causing this. Any screen with a response time of around 20ms should be able to deal with a normal analogue TV signal as this can only change once every 20ms anyway.

    I've seen a similar effect on my HS10, where at the moment I have to use the sideshot and keystone. If I turn these off and have a parallelogram rather than a rectangle, this smearing improves significantly.

    Do you think if i bypass much of the circuitry in the TV and use a HCPC with VGA and a nebula card then I'll get a better picture?

    Phil
     
  6. Stackers

    Stackers
    Active Member

    Joined:
    Jan 5, 2004
    Messages:
    903
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +69
    Like Richard i have the Phillips 30" LCD TV. I watch a lot of Sky Sports News (Sad, i know!!! ;)) And i've never had a problem with the horizontal scrolling text on that channel or any other Sky News channel for that matter.

    I was very concerened after i'd ordered mine! I would go down to Comet and look at their crap setup and panic that i'd wasted a lot of money for no reason. However, since it's arrived i've been very happy with it. Depending on signal strength the picture quality can change but i find that switching from pixel plus to progressive scan fixes this.

    I guess you could wait for the next release but in my experience once you start doing that you never buy anything as you're always waiting for the next best thing!!
     
  7. philsparks

    philsparks
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    There seems to be a pattern with LCDs tht the built-in analogue TV tuners seem to struggle. Maybe as tartan_guru suggests its the noise canceling circuitry. Perhaps there's something intrinsically difficult about it as it seems bizarre for Philips et al to produce a premium product and then ensure that the TV pics when it's demonstrated in most stores will be really crummy. If it is difficult I'm suprised that they don't all already have built in freeview decoders.

    I'm actually quite a fan of normal analogue TV, we've got a whopping aerial with almost line of sight to Crystal Palace, high quality CT100 cable and an attenuator on the end of the cable. With a great signal it's still a suprise how good an ancient 15" portable TV can look.

    Phil
     
  8. carrera

    carrera
    Active Member

    Joined:
    Sep 18, 2003
    Messages:
    76
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    8
    Ratings:
    +4
    I have an NEC VP4 which I'm playing around with at the moment.

    I seem to have the same problem with text, particularly horizontally moving text. I have my old 28" Panasonic CRT at the side for comparison.

    If you look at the news tickers on the news channels, a good exapmle is Bloomberg with the stock prices on the CRT the scrolling is really smooth. By comparion the plasma seems jumpy / jerky as the text goes across the screen.

    Is this common to all plasmas, or is it a problem unique to the NEC ?
     
  9. deman77

    deman77
    Standard Member

    Joined:
    Aug 20, 2003
    Messages:
    260
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    London
    Ratings:
    +0
    lcd manufacturers usually flatter themselves when quoting reposnse times (there are various ways of calcualting them).
    I haven't seen any jerky vertical running text on my D6.
    Vertical credits definitely jump in D5 at least in PAL(50zh) in NTSC(60hz) they seem ok.
    I don't recall spotting any horizontal jerks but then again I don't normally watch anything with tickers so this is not on my checklist to look out for.
    We do have a 2-3yr old 50in Fuji running tickers at work, it jerks really bad. But the picture on it is so bad anyway that this would be the least of your concerns. I can't believe people would actually pay money for such a horrible picture quality.
     
  10. richard plumb

    richard plumb
    Well-known Member

    Joined:
    Jan 27, 2002
    Messages:
    14,271
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Location:
    Windsor
    Ratings:
    +1,015
    I really like the analogue tuner on my screen. It certainly seems to be better than my old TV, and the quality is surprisingly good.
     
  11. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,040
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,111
    The smearing on fast moving action ( like credits and ticker tapes) is down to poor quality deinterlacing. External deinterlacers and HTPCs improve things enormously.
     
  12. Stackers

    Stackers
    Active Member

    Joined:
    Jan 5, 2004
    Messages:
    903
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +69
    Deinterlacing on the Phillips is built in, not sure if you can use an external one with the Phillips or if it would help?

    I agree with Richard, the analogue picture on the Phillips is great....again down to signal strength. I guess the morale of the story is to be wary of the quality of the pics when in JL, Comet etc and go with what people recommend and magazines give good reviews to! I.E. What Video gave the Phillips and Sharp 5/5 (Or thereabouts!!! ;)) but didn't rate the 32" Toshiba!
     
  13. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,040
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,111
    Deinterlacing is always "built in " on digital panels and most digital processing tellies : why you see similar problems on 100Hz tvs.

    If its got a vga or dvi input then you might be able to do a 1:1 pixel map and refresh match to the panel then hopefully a decent offboard solution gets on with the deinterlace and the panel just displays the input as is.
     
  14. Gazzad

    Gazzad
    Standard Member

    Joined:
    Sep 6, 2003
    Messages:
    118
    Products Owned:
    0
    Products Wanted:
    1
    Trophy Points:
    18
    Location:
    West Wickham
    Ratings:
    +2
    I also suffer from this on my current 100Hz Hitachi CRT TV, switching to 50Hz cures the problem but can notice a flicker. If watching football, also get a similar effect on fast moving balls at 100Hz.
     
  15. StooMonster

    StooMonster
    Well-known Member

    Joined:
    Nov 20, 2002
    Messages:
    4,970
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    Kent
    Ratings:
    +314
    It is not the deinterlacers, so switching to an external one won't help. The vertical refresh rate of the internal frame buffer of almost all LCDs in 60Hz, so PAL's 50Hz is having additional frames added. Early plasmas and many LCD projectors are the same.

    It's not just scrolling text this will be happening on, it's there all the time, you just don't notice it unless there is lots of movement.

    This is very evident on my LCD television, but my plasma television on the other hand has internal frame buffers of 48Hz, 50Hz, and 60Hz so doesn't have this frame-rate-conversion judder.

    Plug a PC in and run the JudderTest program and I bet you'll find that your LCD television can only display 60Hz.

    StooMonster
     
  16. sticker

    sticker
    Standard Member

    Joined:
    Jan 14, 2003
    Messages:
    1,152
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    36
    Location:
    Sydney, Australia
    Ratings:
    +0
    I certainly see this on my Pio 503mxe and that is using a Lumagen vision. I don't see it as poor de-interlacing, unless I've wasted £1,300 on the Lumagen :(. My thoughts would be that its a combination of the panel and the poor quality data feed

    John
     
  17. richard plumb

    richard plumb
    Well-known Member

    Joined:
    Jan 27, 2002
    Messages:
    14,271
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Location:
    Windsor
    Ratings:
    +1,015
    hey stoomonster, can you post a link to the juddertest? I'll give that a go, as the specs for the philips says its supports multiple PC refresh rates, up to 85Hz.
     
  18. tartan_guru

    tartan_guru
    Member

    Joined:
    Nov 17, 2003
    Messages:
    154
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    London
    Ratings:
    +17
    My phillips will accept a 50Hz signal via it's vga socket, however I thought that most LCD's and plasmas ran at 75Hz in PAL mode as this is 3 times the 25 frames per second rate and makes the processing much easier
     
  19. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,040
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,111
    I run my panny 37" 5 series at 60Hz for all sources using an HTPC for offboard deinterlacing and scaling.
    Run bog standard interlaced PAL via svideo directly into the panel and it smears , run NTSC into it and that smears too.

    The smearing effect is easily restorable by switching down to less sophisticated deinterlacing techniques on the HTPC. Use a bob deinterlace and you get zero smearing(tickertapes nice and sharp) but microjudder becomes apparent ,(not referring to the horizontal bobbing on artifact) use a field average and you get less appreciable judder at teh cost of smearing on fast motion. ( which also helps to hide the judder as your brain is often fooled into thinking its motionblur but yuor tickertape type credits become unreadable)

    Adding additional frames may well introduce juddering artifacts (we've all seen this on 3:2 pulldowned film material) but perceptual smearing is usually a deinterlace artfact.
     
  20. philsparks

    philsparks
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    gosh I seem to have opened a very complicated issue. I guess from my 'non-expert' perspective the answer is:
    - with the basic analogue RF input the Philips (and JVC?) are pretty good with a good signal, especially if you turn off a lot of the pixel-plus, noise cancellation settings so the electronics aren't working overtime
    - if I then go for the freeview route, then a Nebula card in a good spec HCPC will at least give me the freedom to play with the settings to balance the detail against the smearing and any fram-rate judder.

    Phil
     
  21. Mr.D

    Mr.D
    Well-known Member

    Joined:
    Jul 14, 2000
    Messages:
    11,040
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,111
    The bob deinterlace used in the nebula is actually very good for its type. It still exhibits slight judder but is nowhere near as bad as on previous versions ( this is running my HTPC at 60Hz) The bobbing artifact on horizontal detail is visible but is comparatively slight for deinterlacing of this type. It does resolve a very sharp picture ( tickertapes for example are very sharp and clear).

    There is also a pulldown system in the nebula software that attempts to create smoother display at non-standard multiples ) ie 50Hz pal shown at 60Hz). Considering whats going on it seems to work quite well.

    Switching to "none" as far as deinterlacing goes gives a simple weave which is ideal for film based material.
     

Share This Page

Loading...