Looking for evidence that S-Video is noticeably superior to composite

Discussion in 'Professional Video Production' started by Doc, Apr 13, 2005.

  1. Doc

    Doc Guest

    I recently got a standalone DVD player with various options for video out so
    I've been doing some experimenting.

    Going into a Pinnacle DC-10, running Pinnacle Studio 9 (yes, miracle of
    miracles, I actually got it to work) on a 933mhz PIII Compaq running XP
    Home, going to a dedicated 7200rpm hard drive. I'm viewing the output
    through a brand-new 19" tv. The player is a CyberHome CH-DVD 300. Using
    basic RCA composite and S-Video cables off the rack at WalMart.

    As my test video, I'm using a DVD of Final Fantasy, the CGI
    super-spectacular figuring that should give me about as hi-def an image as
    exists along with a wide variety of images, shapes, shades, plenty of
    intricate detail.

    At this time, I really don't see any discernable difference. Both the
    composite and S-Video output look superb, but identical as near as I can
    tell. They look indistinguishable from the image straight off the DVD for
    that matter.

    Is there any particular type of detail I should be looking at to see where
    any differences might lie?

    The only difference from a technical standpoint that I've seen is that the
    S-Video drops a slightly smaller number of frames. So far 1 dropped frame in
    just at an hour going through the S-Video, around 3 or 4 in an hour with
    composite.

    Maybe I need a more hifalutin' TV to see the difference?
     
    Doc, Apr 13, 2005
    #1
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  2. Doc

    C.J.Patten Guest

    Can't comment on your specific test but I used to own a Sony XBR series 27"
    CRT television and with a Sony Playstation connected via S-Video, the
    picture was noticeably sharper with much less smearing.

    Might be the differences aren't visible until you get into a certain level
    of equipment.
    Next time I'm comparing, I'll take some still shots and put them online for
    all to see.

    C.
     
    C.J.Patten, Apr 13, 2005
    #2
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  3. Doc

    Alpha Guest

    If you google the subject there are websites that demonstrate the difference
    with video captures.
     
    Alpha, Apr 13, 2005
    #3
  4. Doc

    da_test Guest

    On Wed, 13 Apr 2005 18:27:08 -0400, "C.J.Patten"
    I also have a 27 inch XBR, it's past it's best, but the difference
    between the svhs and the composite inputs is still discernible.
    The main difference I see is the dot crawl on straight edges.
    Very pronounced on composite, but almost invisible on SVHS.

    On the otherhand, if the TV has an advanced (3d?) comb filter
    installed, it's probably much closer.
    Dave
     
    da_test, Apr 13, 2005
    #4
  5. Once again Doc, DVD does not hold hi-def whether it is Final Fantasy or the
    Matrix. CGI has nothing to do with it. DVD video is 720x480 whether it is
    letterboxed or full screen.
     
    Digital Video Solutions, Apr 14, 2005
    #5
  6. Doc

    jaykchan Guest

    I have a similar experience as C.J.Patten's. My 25" Sony TV shows a
    noticable improvement when I switch from composite video ro S-video (I
    forgot the model number of the Sony TV). On the other hand, I don't see
    any improvement when I make the same change on two different JVC TV
    sets (32" and 25"). The fact that my Sony TV costed more than either of
    the JVC TVs may have something to do with this.

    Jay Chan
     
    jaykchan, Apr 14, 2005
    #6
  7. Doc

    C.J.Patten Guest

    I've often wondered if lower-end equipment with external S-video ports are
    actually just "soldered" into the same circuit as the RCA jack.
    Same effect as having a $5 external RCA to S-VIDEO dongle.

    Based on what I'm reading here, I'm leaning toward that conclusion.

    C.
     
    C.J.Patten, Apr 14, 2005
    #7
  8. Doc

    PTRAVEL Guest

    I don't think such a thing exists. S-video handles chroma and luminence
    signals separately. You can combine the two mechanically into a single RCA
    connector and wind up with a composite signal. However, I don't think you
    can take a composite signal and separate out chroma and luminance except
    electronically.
     
    PTRAVEL, Apr 14, 2005
    #8
  9. Doc

    David McCall Guest

    One difference between S-video (Y/C) and Composite is
    that the luminance signal (Y) and the Chrominance signal are
    mixed together and sent down a single wire instead of 2
    separate wires as in S-video (Y/C).

    The Y part of the signal contains all of the detail an luminance
    information. Because it is carried separately, S-video can have
    a noticeable improvement in clarity. Before the 2 can be combined,
    some of the detail has to be filtered out so as not to compete with
    the color information. By keeping the color information separate
    the detail of the luma channel doesn't get interpreted as color.

    The most obvious example is when someone on TV wear something
    with tight stripes causing a rainbow of dancing colors. That is because
    tight stripes look just like color to the color circuits in the TV.

    So, the potential difference is better detail, and slightly cleaner color.
    The color bandwidth is limited in both cases because of the way color
    is superimposed on the color subcarrier, so the color doesn't look
    better by as much as the luma detail.

    If an S output is derived from the signal after it has been filtered, then
    it wouldn't be a lot better than the composite out of the same box.

    David
     
    David McCall, Apr 14, 2005
    #9
  10. Doc

    Doc Guest

    In this case, I wasn't actually referring to "Hi Def" as in the Hi Def tv
    system as I did in a separate post. I meant it seems this would represent
    the highest quality image you're going to find on a DVD, though I really
    wasn't up on Hi-Def tv enough to know that DVD doesn't meet Hi-Def specs.

    Of course, this brings up another question - if DVD's are all going to look
    degraded on a Hi-Def TV, that seems to cut out a certain part of the
    incentive to get such a TV. I don't think I could watch a movie that looked
    the way the image did on these things, the jaggedness in the image was
    really distracting.
     
    Doc, Apr 14, 2005
    #10
  11. I think somone else responded by saying that it is likely WalMart and other
    outlets may have been playing the 4:3 version stretched and/or zoomed to
    fill the screen. Also it is likely they did not have progressive scan
    enabled on the sets you saw. I have a Pioneer 50 inch plasma and DVD
    playback looks great. I only play the widescreen versions and do not use
    zoom. Sometimes the variations of letterbox give black at the top and bottom
    of the screen, which is where most would use the zoom function since it
    seems to bother them not have the picture fill the entire display. My
    simplest advice would be to go elsewhere to view the output - Best Buy,
    Circuit City or other places where electronics is their main product. Find
    the display you like and then shop around WalMart and wherever for the best
    price. Best Buy is nice because their stuff is normally given some "same as
    cash" for so many months when you purchase.
     
    Digital Video Solutions, Apr 14, 2005
    #11
  12. Doc

    blackburst Guest

    Just one man's opinion: I have never been impressed by much of a
    difference between composite and S. On a crappy image. both look
    crappy, and on a good image, both look good.

    But I'm spoiled by working in TV. For most of that time it was BetaCam
    and component, lately it's DVCam, DVCPro and SDI.
     
    blackburst, Apr 15, 2005
    #12
  13. Doc

    Larry J. Guest

    Waiving the right to remain silent, "PTRAVEL"
    You can jam Y and C together as you've described, and it may be good enough
    for some sloppy monitors, but it wont fly in many other uses.

    In a true composite signal, Y & C are interleaved, with the proper phase
    relationship, an electronic process.

    You're 100 percent right about the other process.

    --
    Larry J. - Remove spamtrap in ALLCAPS to e-mail

    "If you take out the killings, Washington actually
    has a very low crime rate."
    - Marion Barry, mayor of Washington, D.C.
     
    Larry J., Apr 15, 2005
    #13
  14. Doc

    Larry J. Guest

    We've recently upgraded to Cox digital cable and got their HD option. For
    the most part, it looks very nice on our Toshiba RP set. About fifteen
    channles of HD now, a real good reason to have an HDTV..!

    --
    Larry J. - Remove spamtrap in ALLCAPS to e-mail

    "If you take out the killings, Washington actually
    has a very low crime rate."
    - Marion Barry, mayor of Washington, D.C.
     
    Larry J., Apr 15, 2005
    #14
  15. Doc

    kashe Guest

    FWIW, my new HP Media Center (tm -- I'm sure) came with such a
    dongle. Checking the pinout (and numbering the S-video pins clockwise
    from the key), I found the RCA center conductor connected to pin 2,
    RCA shield connected to pins 1 and 4. No connection between the
    S-video shield and anything else nor the S-video pin 3 and anything
    else. Both ends were as small as would be expected, so I have no
    reason to suspect there were any additional electronics buried in the
    assembly.

    Googling 's-video rca connector' finds many such devices,
    mostly described as bidirectional. One such description --

    -----------------
    <http://www.buy.com/retail/product.asp?sku=10362705&loc=&rp=true>
    The Bi-Directional RCA to S-Video Adapter from Cables To Go is a
    low-cost alternative to high priced active converters. This
    bi-directional video adapter is designed to convert composite RCA to
    S-Video or vice-versa. The Y/C signal separation circuitry provides a
    bright, crisp picture from DVD, VCD, laser disc, VCR, camcorder and
    multimedia PC.
    -----------------

    Based on what I found in the pinout, I strongly doubt they
    contain such "circuitry" and consequently doubt the ability to convert
    in the RCA to S-video direction.

    An apparently more accurate description, found elsewhere
    reads:

    -----------------
    <http://www.ramelectronics.net/html/adapters.html>
    S-Video female connector to female RCA composite video
    "bi-directional" adapter. Female connectors on both sides.
    The adapter works nicely from a composite video source to an S-Video
    destination as well as in the reverse with no noticeable Chrominance
    or Luminance abberations. Tested with Digital Cable S-Video and
    Composite video outputs to Sony® 51HW40 HDTV S-Video and composite
    video outputs using Monster Cable®, and MaxCable® S-Video and
    composite video cables. *Converting from S-Video to composite video
    must always have some slight negative effect since the Chrominance and
    Luminance signals are combined and no longer kept seperate.
    -----------------

    I'm far more inclined to believe this latter description,
    especially the last line.

    Perhaps a more expensive "active" converter might be able to
    reconstruct the originals of the two combined signals.
     
    kashe, Apr 15, 2005
    #15
  16. There was a circuit published on the web a year or two ago, or in a
    news group, I forget the location and the details. It was to make a
    combiner for S-Video to composite on the cheap.

    The chroma connection to the center conductor was via a capacitor
    (small - a few dozen pF, IIRC), so it would show infinite resistance to
    any ohmmeter check...

    <SNIP>

    HTH,
    Gino
     
    Gene E. Bloch, Apr 16, 2005
    #16
  17. "Gene E. Bloch" wrote ...
    http://www.epanorama.net/circuits/svideo2cvideo.html
     
    Richard Crowley, Apr 18, 2005
    #17
  18. Thaks - now I don't have to find the cable I made and take it apart :)

    (It's been too long - I couldn't find any references on my computer or
    I would have put one in my previous post...)

    Gino
     
    Gene E. Bloch, Apr 19, 2005
    #18
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