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Activity Forums Adobe Encore DVD weird luminance trouble

  • weird luminance trouble

    Posted by Papito00 on April 9, 2005 at 9:53 pm

    hi, i’m having this situation…i capture my video and export it as uncompress avi, everything looks fine, when i build the proyect it looks like if the the luminance of all the video has go up to the sky, can this be an encoding trouble? any solution for this?
    thanks guys

    seanmchenry Sean mchenry replied 19 years, 2 months ago 2 Members · 1 Reply
  • 1 Reply
  • seanmchenry Sean mchenry

    April 19, 2005 at 1:02 pm

    This is a major issue we have discussed till we were all exhausted at the dvinfo.net forums.

    Here are the basics. Try to keep up, it’s a big problem…

    If I am shooting in digital, DV, DVCam, DVCPro, DigiBeta, etc, the spec for that digital video format state there should be no setup (should be 0 IRE) on the original material. Hopefully you all understand the concept of “setup”. It basically says that real black has a value of 0 IRE units, for digital video, or 7.5 IRE for analog video. That’s the quick summary. Don’t worry about why right now. It’s a rule.

    So, back to the issue. It seems all US DVD players will automatically add setup to video playing back to a standard television as the DVD player assumes it is supplying the jump from the digital realm of 0 IRE to the analog world of your TV, Plasma, etc., at 7.5 IRE. It may have to do with thinking all DVD video is from film which has no setup level and so the DVD player should add it to make the video translate to your analog television correctly.

    If when you author your video, you add setup back into the mix by say going back to tape and bringing the video back in via another application, or settings in your MPEG-2 compressor of choice are set to add setup, what happens on the other end, at your DVD player is, you get not only the accidental 7.5 analog that you may have mistakenly added, but you now also get that additional 7.5 bump up that your DVD player is going to blindly add in for you. Now your black levels have gone from 0 IRE where they started to 15 IRE at your Television. Your crisp, well shot blacks are now a deep grey. Your whites are off the chart too by now, unless your DVD player clips them. Either way, that’s just as bad.

    All the folks on other continents have it way to easy as this is a non-issue for most folks outside the US.

    Basically, this is a mess. In my personal opinion, we either need to scrap the 7.5 IRE setup at the NTSC Television set level (which won’t happen as accurate video delivery using 7.5 IRE is built into the manufacturing process for all sets delivered to the US) or we should have made the DV (and other digital video) specs meet the 7.5 IRE qualifications. Just as doubtfull.

    Basically, make sure you use a workflow which adds no setup levels to your video if you are delivering on DVD alone.

    What really sucks is if you are going to analog tape and DVD, you really need two different versions of the finished program. One with 7.5 and one at 0 IRE.

    This can be handled however with some of the more expensive DV based (DV, DVCam, DVCPro, etc) decks by flipping a switch to “add setup” to the analog outputs of the tape deck. This would allow you to make a VHS dub and have the setup be correct for example. Alas, the lowly DSR-11, one of the decks I proudly own and use is lacking this feature.

    Television stations also have this issue so, when delivering a tape to a station for on air playback, you also need to be sure you do NOT have added setup, if you are handing them a digital (DV, DVCam, DVCPro, DigiBeta) tape. I mark my tapes to let them know if it does or does not have 7.5 IRE setup so they know to dub it into their systems appropriately. Of course most US stations are on autopilot and don’t have actual Engineers these days but somebody there might still know what we are talking about.

    Hope this wasn’t too much to follow. Google video setup levels and you can find a BIG can of worms.

    Sean McHenry
    Deep Blue edit
    https://www.DeepBlueedit.com

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