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I Need A Volunteer

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by 1953, Apr 21, 2012.

  1. 1953

    1953 Icon

    738
    7
    Feb 7, 2006
    Desoto, TX
    When viewing Wheeler Dealers, channel 281, VEL, we see shimmering on just about each eposoide. The shimmering can be seen on the automotive shop's corrugated steel garage door and on car grills, trim, etc.. The shimmering is sporadic. Since I only observed this on Wheeler Dealers and once or twice on the Mechum Auto Auction show I'm hoping there's no equipment or cabling problems.

    I need a volunteer to either view or record and view Wheel Dealers to tell me if they see this "shimmering". Your help will be greatly appreciated.

    1953

    Other Information:

    Directv 24-500 DVR
    Denon AVR 1912
    Sony KDL-46HX750
    Monoprice Premium 24AWG High Speed HDMI cables

    An HDMI is routed from the DVR to the AVR. A master HDMI connects the AVR to the Sony HDTV.
     
  2. sigma1914

    sigma1914 Well-Known Member DBSTalk Club

    14,583
    369
    Sep 5, 2006
    Allen, TX
    Describe what you call shimmering please.
     
  3. 1953

    1953 Icon

    738
    7
    Feb 7, 2006
    Desoto, TX
    Wheeler Dealers
    On the garage door the corrugated steel develops multiple (grouped) horizontal "U or V" shaped shimmers. The shimmers stay within the borders of the garage door.

    On horizontal car trim the trim has shimmering broken angled vertical shimmering lines.

    As I said before, these effects are sporadic. On Mecheum the effect is only sometime seen on horizontal thin side trim.
     
  4. sigma1914

    sigma1914 Well-Known Member DBSTalk Club

    14,583
    369
    Sep 5, 2006
    Allen, TX
    I watched the last 15 minutes of the show currently airing. I just saw it on the door. It's the show/channel....your equipment is fine. That door did weird psychedelic tricks for a moment. :lol:
     
  5. 1953

    1953 Icon

    738
    7
    Feb 7, 2006
    Desoto, TX
    Thanks for your help sigma. I'm at ease now.
     
  6. TomCat

    TomCat Broadcast Engineer

    4,153
    100
    Aug 31, 2002
    I'll take a wild stab...

    This happens when there is a change of resolution, either a change from the original to a different resolution (from the produced resolution to the network native rez) or from the received rez to the displayed rez, or any other sort of combination. It is especially noticeable when the original is interlaced, SD interlaced usually, and the change is to progressive, such as when watching an SD show on a 1080p monitor.

    It also happens when there is a time-compression algorithm applied to the original material, which a lot of stations do.

    It does not happen with most conversions, because most are done with care. Maybe not so much in this case.

    If you have a situation visually where there are parallel lines close together, any motion can make those strobe against the frame rate of the video. It is not all that different from the "wagon wheels turning backwards" stroboscopic effect that 24 fps film can have. When there are not such lines or patterns, or no motion, the artifact is usually not visible. If the lines are close enough together, you get a moire effect (a similar artifact but with very close lines), which is why newscasters are told to never wear checked or tweed jackets or pinstriped shirts on camera. (taste alone would forbid that)

    Dollars to donuts, without seeing what you are seeing, this is what you are seeing.

    So, its normal; nothing is amiss. Its just part of the imperfect world of scanned video.
     
  7. 1953

    1953 Icon

    738
    7
    Feb 7, 2006
    Desoto, TX
    Great technical explanation.
     

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