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video format conversion

Discussion in 'Nvidia' started by Hactar, Jul 8, 2009.

  1. Hactar

    Hactar Guest

    First, is it possible to convert 4-pin S-video to either component or
    7-pin S-video?[1] I see adapters from 7-pin S-video to component all over
    the place, and I have several. Extra power bricks are not a problem.
    It should cost less than a VGA -> component converter else there's no
    point. Second, if so, how?

    Anyone have success getting the Linux Nvidia driver to show color through
    an S-video -> composite adapter?[2] Maybe a kernel tweak is required?

    [1] I have an EVGA Geforce 6200 in a computer I'm trying to turn into a
    DVR. It has a _4-pin_ S-video out, but the amp doesn't have an
    S-video in. I have to stick with analog video unless I want to convert
    the computer, TV, and DVD player all three. (The amp won't convert
    signal formats for me.) So, my choices are component or composite.
    Component connections are much higher quality, but right now I have it
    connected by composite.

    [2] See, the way I have it set up now (using an S-video -> composite
    adapter) it shows the desktop in greyscale. I looked that problem up
    on the web and all the solutions boiled down to "use S-video". Great,
    would if I could. I know the hardware works because the Energystar
    logo in the BIOS is in color.
    Hactar, Jul 8, 2009
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  2. Hactar

    Phil Weldon Guest

    'Hactar' wrote, in part:

    "S-video" is merely a two analog signal version of composite video. One
    signal is the luminance (gray scale) video with sync pulses, the second
    signal is just the chroma signal. For composite video, the chroma signal is
    encoded and mixed with the luminance signal. The resulting mixture has less
    resolution than "S-video" can provide. From your report it seems that your
    "S-video" to composite video adapter is not working, or a conductor is
    broken. All that is necessary to convert an analog "S-video" signal to an
    analog composite signal is to mix the two signals, possibly running the
    luminance signal through a low pass filter first. This should be a
    completely passive filter consisting of the adapter shell and two 4-pin
    connectors, plus a few resistors and capacitors.) The BIOS splash screen
    displays BEFORE the video drivers are invoked, and BEFORE the operating
    system is loaded. I suggest you borrow a device that HAS an "S-video" input
    and check for color before and after the operating system is loaded.

    As 'First of One' posted, a 7-pin connector is not an "S-video" connector.

    Finally, have you tried using Google? Try the search string S-video to
    composite adapter and you will find complete explanations and adapters
    costing as little as $4 US.

    Phil Weldon

    Phil Weldon, Jul 8, 2009
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  3. Hactar

    Hactar Guest

    Noted. That's why conversion is easy I suppose.

    Then is there any way to convert true S-video to anything besides composite?
    Automatic switching. Tell the amp "source=DVD" it routes DVD sound ->
    speakers and DVD video -> TV. Same with the DVR.
    Both. I have a 4-way switch that handles S-video, composite, and sound too.
    I'll try that. One of my goals was to get an amp that handled video so
    I could ditch the manual switch.
    Yep, memory countup, drive enumeration, the lot. I gather that before
    the OS loads the card simply mirrors the video stream on VGA, DVI and

    -eben royalty.mine.nu:81
    Hactar, Jul 8, 2009
  4. Hactar

    Hactar Guest

    The hardware acts like it works, since I get color in the BIOS. The
    adapter's a piece of molded plastic anyhow (like those DVI->VGA adapters),
    so a broken wire is unlikely.
    Why two?
    Indeed. By that nature, it shows the capabilities of the hardware
    Yes. All of the solutions boiled down to "use S-video" which isn't an
    option for me (amp doesn't do S-video). Sure, I could use it if I went
    to manual switching. I have the switch and enough S-video cables.
    Yes, got one. Radio Shack and the local computer store each sell one
    also. However, I was trying _not_ to use composite since it looks bad
    (relatively speaking).
    Hactar, Jul 8, 2009
  5. Hactar

    Phil Weldon Guest

    'Hactar' wrote, in part:

    #1. "Why two?" So the chroma frequencies will not interfere with detail in
    the luminance signal. A device that has a composite video input must
    separate the chroma signal from the luminance signal before further
    processing the signal. The luminance signal eventually controls the
    brightness of each pixel on the screen while the chroma signal is decoded
    into three color signals, one each for Red, Green, and Blue. Separating the
    the chrominance signal out reduces the resolution of the luminance signal
    and thus the resolution of the image on the screen.

    #2. "Indeed. By that nature, it shows the capabilities of the hardware
    alone." True, but not sufficient for diagnosis. For example, the video
    card may output composite video during the splash screen BECAUSE THE VIDEO
    CARD BIOS IS NOT FULL INVOKED. Don't jump to conclusions. That's why I
    suggested using a device that accepts 'S-video' input as a check.

    #3. "Yes, got one. Radio Shack and the local computer store each sell one
    also. However, I was trying _not_ to use composite since it looks bad
    (relatively speaking)." Well, yes, composite video will look worse than
    'S-video', component video, or any kind of digital video. That's the nature
    of composite video. No conversion of composite video to 'S-video',
    component video, or digital video will improve the original image. Most
    likely the result will be a degraded image.

    Phil Weldon

    Phil Weldon, Jul 8, 2009
  6. Hactar

    Hactar Guest

    Macrovision in the amp? OK. Sucks that the amp is preprocessing my
    data stream.

    As to the driver, if the "Mythbuntu" logo should be in color (I don't
    see it that way) then since that appears way before X and the Nvidia
    driver load, it would have to be an OS bug.
    I think in this TV S-video is automatically used if present, else it
    falls back to composite. There are no component or digital inputs or
    a way to pick the input (other than whatever it calls AUX).
    Hactar, Jul 9, 2009
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