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Dscaler , capture cards and noise

Discussion in 'Desktop & Laptop Computers Forum' started by Mr.D, Sep 6, 2002.

  1. Mr.D

    Mr.D
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    Hey

    I use Dscaler and a pinnacle PCTV card and its great. The adaptive noise filter helps a lot but I do get a fair amount of video noise (and the filter hates smokey enviroments I noticed!). Whilst I'm willing to plump for a falcon or similar to lose the noise I'm wondering if there is a more simpler solution to improve the pinnacle.

    In my experience RF inputs on most kit are extremely noisy generally and tend to leak into the rest of the circuitry on say TVs and vcrs most commonly .

    I'm wondering if the noise a lot of people see on the cheaper cards is mainly down to the noisy RF input that most people don't use anyway.

    Short of buying a black burst signal generator and an RF encoder to feed into the RF input I was wondering if there is any way to knock out the RF input so it effectively gives neutral black rather than static: short circuit it or something? In the meantime I could select a dead channel from my digibox ( plenty to choose from!) and check for a noise improvement using another source ( the Xbox opening screen shows up the noise nicely). This would be a pain though.

    So anyone know how to take out the RF so its getting black rather than just static?
     
  2. Jeff

    Jeff
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    I don't know the answer but its an interesting point. I believe a fair portion of the noise comes from the video card. In the old days I noticed things went decidedly worse when I moved from a Geforce 2 to a Radeon. The other thing is that cards without TV tuner and RF input are still noisy.

    Jeff
     
  3. Chris Muriel

    Chris Muriel
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    Hopefully the tuner itself (the RF bit) will be in a screened can. I wouldn't try shorting anything anyway ; you'd be more likely to destroy your card.
    1 simple thing you can do, since you aren't using RF input, is to fit an antenna plug into the aerial socket (probably a standard belling-lee type) that has a 75-ohm termination resistor in it - i.e. the tuner input sees 75-ohms between centre & ground. This would need to be a non-inductive resistor . You can buy termination plugs like this in BNC form - but I haven't seen a belling-lee type (thought these may exist). If you used the BNC type (via a decent quality adaptor) , you would have to make sure it was 75-ohms - there are also 50-ohm types !
    I would also experiment with moving the card into different PCI slots to see if this made any useful difference in terms of noise pickup.

    Chris Muriel, Manchester.
     
  4. Mr.D

    Mr.D
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    Yep I take the point about the non RF cards having noise issues too. Thanks for the info on the termination. I've got plenty of aerial connectors lying about and I'm sure I can lay my hands on a suitable resistor.

    Time is a bit of an issue though at the moment.

    The capture card is on the slot furthest away from the AGP port. I'll try the tinfoil sandwich trick too. Must admit the adaptive noise filter does help a lot. I'll probably swap out the quietPC power supply for an enermax too . ( the quiet PC one can go in the P4 machine I'll be building in the near future).
     
  5. Rob.Screene

    Rob.Screene
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    I tried DScaler 4.0 Alpha last night, in place of DScaler 3.1 I think it can be used by a few of us to reduce video input noise for free.

    It has a nice automatic calibration that worked well with the THX optimode test screen on my Star Wars Episode1 (PAL) disc. I was calibrating for S-Video input from a Playstation2, so I used the DVD in the Playstation2.

    On starting the calibration, Dscaler appeared to set the black and white levels nicely, plus hue and Y and V values appeared to be tweeked for me (I must confess I don't understand effects of Y and V value changes in this context).

    On checking the black-level test screen on the DVD, I noticed the projected black-level was way too low, so I enabled the Overlay adjustment now in dScaler and adjusted brightness, contrast and gamma for the overlay output.

    I think before (with DScaler 3.1) I was not using the full-range of the IDS Falcon capture card, because I had the S-Video analog input black-level ramped because of the dark Radeon overlay. I'm using old but good 7075 drivers for TheaterTek compatibility but they have no generic overlay controls. There are newer drivers with their own overlay controls, but most have drawbacks and are nowhere nearly as easy to use as DScalers.

    Now, with the correction applied digitally in the 10-bit Radeon Overlay settings (within dScaler) the noise level is so low, that I no longer see a benefit of running the Noise filter (Gradual). It has also allowed the overlay gamma to be upped a bit, without using the Gamma filter which add some cpu cost.

    I can run Deinterlace, Video (Greedy, High motion) without any dropped frames on a Pentium3 1GHz, it looks fabulous and is very, very smooth, playing Gran Tourismo3 for a few hours last night.

    It's a definite improvement in smoothness and the auto calibration (see the helpfile for more info it appears to have been updated and is very useful) and overlay control has made a big improvement to noise I get without the Noise(Gradual) filter.

    BTW. The newer Video(TomsMocomp) deinterlace mode drops frames, even if it's setting is lowered from the default of 5. Looks like that Northwood Pentium4 that I will get with my Dign case will have more use than just compressing Laserdisc captures to DVD!

    Anyone seem how good Video(TomsMocomp) is when it's not dropping any frames?

    All in all, this appears a fantastic release. Seems stable and the reworked menus make much more sense. Ilike the filters and deinterlacing modes renamed to show firstly what they are for, like Noise(adaptive) or Noise(gradual) and
    Video(Greedy,highmotion).

    Now, I must make a new Girder export group for remote controlling it!

    Well done John and co.
    Rob.
     
  6. Jeff

    Jeff
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    I use TomsMoComp (search set to 5) and the gradual noise filter, I get no dropped frames with width set to 768. It looks good but I'm sure it could be better with a higher quality analogue capture card. For my SDI DVD setup I use the adaptive deinterlacer.

    Jeff
     
  7. Rob.Screene

    Rob.Screene
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    What CPU and bus speed are you running Jeff?

    BTW, my test above was using the setup default other settings, like Judder Terminator enabled, which I never even tried in DScaler 3.1

    regards,
    Rob.
     
  8. Jeff

    Jeff
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    I have a 2 PIII 1.2 512kb cache 133FSB. For PAL stuff judder terminator is probably left off.

    Jeff
     
  9. Mr.D

    Mr.D
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    similar here: no dropped frames running Toms mocomp , adaptive noise and gamma filter. Judder Terminator is also on.

    Also autocalibrated the capture card settings using the phantom menace disc.

    I initially set my overlay to the scoped values for the hardware from theatertek:(observation of test patterns showed these to be healthy with regard to black point whitepoint and colour... ie no clippin or crushing) however I believe these settings were with reference to a CRT type display gamma of 2.2 and have since ascertained my panny ae100 is somewhere in the region of 3.1 dropping the gamma on the overlay to 0 gets me to about 1.5 overall end to end gamma. However the gamma filter in Dscaler lets me get that little bit closer to 1.2 beyond the tolerance of the card overlay ( judged by using the Avia gamma pattern which conforms to 2.2 when your end to end system gamma is 1.1-1.2 (ie correct when viewing video material )

    When playing xbox games I lift the brightness on the capture card: otherwise I leave everything alone: again reference to test patterns shows Dscaler to be as correct as it can be on my system(putting patterns through my dvd player then through the standalone RGB to s-video convertor)

    using a 1.13 P3 tualatin.
     

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