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DVD player manufacturers vs. ITU-R601

Discussion in 'Blu-ray & DVD Players & Recorders' started by Zacabeb, Jan 28, 2004.

  1. Zacabeb

    Active Member

    Jan 17, 2002
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    I managed to burn some of my test pattern (my own test patterns and the Philips pattern) onto a CD-R as MPEG2 files and play them back through my Philips DVD737, and made some interesting but annoying discoveries.

    At first I centered the test patterns dead in the frame, both horizontally and vertically. That is, 9 pixels padding on either side of the 702 active pixels and a height of 576 active pixels with the test pattern's center in the physical center of the digital frame. What happens upon playback? Well, the test pattern is offset to the right. A lot. Just as much as my digibox, only there everything is shifted to the left. In my digibox I know exactly why it is so; because it is cropping all 18 pixels of the digital blanking from the left side only.

    So what did I do? I remastered the test patterns shifted 9 pixels to the left (=no leading digital blanking at all) and *bingo*, it's in dead center (between the TV's pillarbox bars that is, not the screen bezel), just like the exact same test pattern when received off-air from an analog broadcast.

    I then hooked the DVD player up through a SCART switchbox with an RGB switch, to make sure the phenomenon is not partially related to internal delay. And it is not, the picture is dead center also in composite. So while my digibox is cropping all 18 pixels from the left, my DVD player is cropping all 18 pixels from the right. So much for standards... :rolleyes:

    But the picture is displaced vertically as well, and here I have no reference since my TV has never been set up properly (I have set up the geometry once using these test patterns via a Hollywood Plus card, so it is at least way better than it was originally, and then I centered the picture using an off-air Philips pattern). Where is the center of the screen anyway? In the exact middle of the digital active area? Below it? Here I was putting those test patterns onto a disc so I could set up the geometry on my TV set, and my evil DVD player does this to me. :(

    Why don't the manufacturers go by the same standard, since the picture is shifted all over the place on different devices? Are they too poor to pay for the ITU-R601 standards books?

    Does anyone here have any insight into where the horizontal and vertical centers should be in the digital active area? If so, please let me know. :)

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