VGA image is better than my Component.. WHY!! Help

Discussion in 'Displays' started by RichardJames, Jul 12, 2004.

  1. RichardJames

    RichardJames Auditioning

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    Please help me understand what is going on here !!

    Equipment:
    HP Digital VP6120 DLP Projector
    Pioneer DV-525 DVD Player

    The problem I am having is this, when a watch certain movies I seem to be getting vertical lines through some parts of the picture. This is through component output.

    When I watch the same as above through my laptop dvd player the picture quality is so much better. No vertical scan lines. VGA output.

    I have a link below with a couple of digital photos of the problem.

    svc035.bne034u.server-web.com/vga/index.html

    I think it seems to happen on bright parts of the picture. With the picture in the above link you can see the fish has vertical lines.

    I don't know why this is happening. My understanding is component is much, much better than VGA. So if that is the case why am I getting vertical scan lines ?

    If it turns out you will always get a better picture through a pc because the resolution of a pc is higher, then why would you bother using a dvd player. Would it not be better to view movies via a pc dvd player ???

    Could someone please explain what is going on :)

    Thanks
    Richard
     
  2. NickSo

    NickSo Producer

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    Actually, an Upconverted signal via VGA from a computer will look MUCH better than your ususal 480p progressive connection from a player like your pioneer, whcih does not have a high end deinterlacing chip like ones from Faroudja.

    So im not surprised that the VGA image is much better than your component connection..

    However, for the Vertical scanlines, i have no clue what is causing that.
     
  3. RichardJames

    RichardJames Auditioning

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    Thank you for your reply.

    So basically what you are saying is that the dvd player i have is not producing a high quality image via component output because it does not have a high end deinterlacing chip?

    If so, what is considered a good dvd player that will produce crisp images.

    Thanks
    Richard James
     
  4. RichardJames

    RichardJames Auditioning

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    Also, I should mention as I think this may be a factor in the image quality issue. And I apologise for mentioning this earlier (slap my wrist). I am using an RCA cable temporarily as a component connection between the dvd player and the projector, whilst I am waiting for my proper Component cable to arrive. So this may be the reason why the image is poor. What do you think ?

    Thanks
    Richard James
     
  5. NickSo

    NickSo Producer

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    Something like the Panasonic XP30 with the Faroudja deinterlacer Chip. Another very popular one is the Zenith DVB318 which has a NEW faroudja chip which upconverts DVD to 1080i (HDTV resolution), similar to what your computer was doing.

    Just to be sure, you know the component connection consists of THREE seperate cables right? They're color coded usually with Red, Blue and Green connections.

    If you are using ONE RCA cable, you are probably connecting using a COMPOSITE connection, which is fairly low quality.

    Also, was the RCA cable a video cable, or audio cable? Using a lower quality RCA cable for composite video will usually cause diagonal banding distortion (in my experience).

    For short component runs, its fine to use three decent quality shielded composite video cables.
     
  6. RichardJames

    RichardJames Auditioning

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    Hi

    I am using a 5 metre RCA video cable (red, white and yellow) in the component input/output. I am aware what composite is and I am not using that method. I am just matching the outputs (ie. red to red, yellow to blue, and white to green) hope that makes sence.

    Cheers
    Richard
     
  7. ChrisWiggles

    ChrisWiggles Producer

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    Your understanding here was incorrect. VGA is RGBhv, which is the best analog video transmission method there is. ARguably, component can be as good, however, it is crushing 5 signals into 3 wires, so for the absolute best, professional products all use RGBhv transmission usually.

    Basically, your computer is a far superior source than your DVD player. You have discovered by luck, the reason that people use HTPCs to do video processing rather than using plain DVD players. I would recommend you peruse (carefully...it's a scary place) the HTPC forum at AVS for more discussions.

    Basically, to take advantage of projectors (and especially with the high-end projectors out there), you need some kind of video processing between the DVD player and the projector, but high quality processing can cost tens of thousands of dollars. A computer is essentially doing this for you, and it can be fairly involved to do it very well and match those extremely expensive outboard processors, but it can be done for fractions of the cost. Since you have a digital projector, what you ideally want to do is scale your computer's resolution to *exactly* the native panel resolution of your projector, which will then bypass *all* the inferior internal processing of your projector, and give you by far the best picture quality that you can get in your setup. Hope that explains things!
     
  8. Max Leung

    Max Leung Producer

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    Ewwwww, no wonder you're getting vertical lines...that kind of cable will give very poor results. Real component video cable is of much better quality and has a higher bandwidth than typical RCA cables.

    Heck, a 5 meter RCA video cable can't even pass coax digital audio properly...I know, I've tried!
     
  9. Allan Jayne

    Allan Jayne Cinematographer

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    >>> I am just matching the outputs (ie. red to red, yellow to blue, and white to green) hope that makes sence.

    It might work better if you use the yellow cord for the green jacks. Still, the quality of the red and white cords is unknown and a cable set designed for component video with red, green, and blue plugs (or three separate yellow plug cables) will work better.

    VGA and component, circuitry wise, can be of equal quality.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  10. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Are sure about this? A video cable has the same impedance as a coaxial digital cable. Moreover, digital signals will pass just fine through an audio cable as well. I'm using an 8 meter no-name car stereo interconnect for coaxial digital and don't experience any problems.


    Aaron Gilbert
     
  11. Max Leung

    Max Leung Producer

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    Aaron, I just tried it with a cheap RCA 5 meter cable (with the yellow, white, and red plugs)...no dice! There are a lot of crappy cables out there.

    I'm using a 3 meter Audio Research audio cable (twice the price of the cheap stuff) and it works fine. And it's just an audio cable...

    So, yeah, in theory any ol' RCA cable should work - my experience is that cheap cables sometimes don't. [​IMG]
     
  12. ChrisWiggles

    ChrisWiggles Producer

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    No. In theory a 75ohm coax cable should be what you use. That's the spec, and there are reasons for that. You can suffer dropouts and such if you use "any" old cable. Same for video, though IMO video is much pickier.
     
  13. Bill Slack

    Bill Slack Supporting Actor

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    It's likely the cables... using three yellow video cables might help. The audio ones tend to be cheaper and should only be 50ohms instead of 75. You'd end up getting interference which is what you may be seeing.

    But, in the end, the VGA connector is a superior to component anyway, for the reasons mentioned above. But, in practice, you shouldn't see a difference, so find a better temporary cable.

    Digital audio and analog video cables are both just 75ohm coax, so a quality cable should work fine. I use old composite cables for both in my system without a hitch.
     
  14. RichardJames

    RichardJames Auditioning

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    I just want to thank you all for your guidance in relation to the issue I posted. I have decided to invest in a HTPC. VGA obviously is the way to go and that will be my solution. I expect to have my HTPC early next week, when I have set it up and tested it I will followup with the results.

    I never expected to get great picture quality from this composite cable being used as a component cable anyway.

    After purchasing my very long awaited projector, who can wait for the proper cable to arrive? I would have used string if it would have worked, just to play with my new toy (haha).

    But your advice above has really assisted me. Again thank you all.

    Richard
     
  15. ChrisWiggles

    ChrisWiggles Producer

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    I feel ya with that one! I spent about 100 bucks on a breakout cable and video cables (BNC connectors needed) to hook up my projector with RGBhv so I could watch flicks. Ridiculously overpriced for crappy cables, but when you need something *now* locally, it's worth it! [​IMG]

    Nothing worse than having a new toy and just staring at it.
     

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