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DTV converter question

Discussion in 'Electronic Repair' started by Jimw, Jan 18, 2009.

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  1. Jimw

    Jimw Guest

    I got a DTV converter. I have a 3 year old 25 inch standard CRT tv.
    Some of the channels fit the whole screen, but others have a lot of
    black around the edge, leaving me with only something like an 18 inch
    square in the center of the screen. WHY?

    There is some option on the converter menu to "change aspect ratio".
    I tried all the 3 settings. one of them is all wrong, the other is
    this square in the middle, and the 3rd is AUTO, which is where I have
    it set, and that is the default (recommended) setting. There is no
    way to make the picture fit the whole screen.

    I know that some DVD movies have Wide Screen, so they end up with a
    black bar on the top and bottom, but using the converter, there is a
    black border all the way around the picture. This dont seem
    right.....

    I noticed that one of the channels has TWO channels from the same
    station, like 8.1 and 8.2. Sometimes they are both the same
    programming, but not always. But one of them fits the whole screen,
    and not the other.

    It seems like this is all the way the stations are sending the
    picture, not anything I can control (I might be wrong). But if I am
    right, what is the purpose to making a small picture like that. On
    analog, the full screen was used on all channels.

    Can anyone please explain this.

    By the way, I emailed one of the stations about this, but never got a
    reply.

    Jim
     
  2. The quick answers are:

    1. It's whatever the station decides. The Aspect options on the DTV
    convertor (or DTV for that matter) may or may not probide a better
    fit over "Auto".

    2. Each station can have multiple programs. If the old channel was
    12 (which would be 12.0 on a DTV, the original analog channel),
    for example, 12.1 is the equivalent DTV channel. But there can
    be 12.2, 12.3, etc., with totally different programming.
    And this surprises you? :)

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  3. Rich Webb

    Rich Webb Guest

    What you're seeing is a 4:3 picture that is formatted to show correctly
    on a 16:9 screen that is *actually* (in your case) being seen on a 4:3
    screen. It's just like the Wide Screen (black bars top and bottom) view
    you describe above except that on their end, the station/network added
    more "black bars" to the left and right.

    On a real widescreen setup, you'd see just the 4:3 picture centered on
    the screen, with correct aspect ratio and a couple of black bars on the
    side. Your converter box, however, sees that it's getting fed a 16:9
    image and displays it as it thinks it's supposed to be seen, just like
    any other "wide screen" picture, with black bars on the top and bottom.
    Result? A small 4:3 picture surrounded by black bars.

    On some converter boxes (Zenith, Insignia (Best Buy's Zenith-in-our-box
    brand), others) there's a "crop" option that takes the center 4:3
    portion of a 16:9 picture and expands that out to fill the 4:3 frame.
    Some converter boxes don't have this option, apparently.

    In other cases, the station "does it for you," sending one subchannel in
    HDTV 16:9 and just the center 4:3 part in a second subchannel for SDTV,
    resulting in what you've described with the same programming on two
    channels, one of which works.
     
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