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  1. Member
    Join Date
    Feb 2008
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    United Kingdom
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    During the final weeks of my using Pinnacle Liquid 6, a strange problem appeared in that timeline/output window footage would suddenly 'lose some of its blackness'. Basically, everything on the timeline was suddenly a shade lighter in colour, as if 'black' had been turned up in colour corrector.

    Blaming Liquid 6 entirely for this (it was failing in other areas too), I quickly finished off my outstanding projects and ensured I had made colourfast - i.e. 'fully black'! - .AVI files (for I found I could get the timeline output colour to revert back to normal by adding random things such as an extra video channel...) before I got rid of the software in favour of Avid Liquid 7.2.

    So far so good with the new Avid, but during some encoding today with WME, I noticed during playback of a WMV file in WMP that the 'greying' is back! That is to say, the .AVI file I ensured was saved with the correct colouring had apparently been 'lightened' again during WME conversion. So I then checked the original .AVI (which I knew had played previously in correct colour), and that too was now lightened. Ran some tests in other media players: both .AVI and WMV versions are lightened in all but VLC, where they play with correct blackness colour. Then tried both files again in the other media players... and colour is okay again on both!

    So that is the background of this unwanted phenomenon I am experiencing. My old editor, and current media players, display - SOMETIMES ONLY - my films in a lighter colouring than they should be. Because I can seem to get the grey to revert back to black by simply 'trying out other media players' etc (or bizarrely by adding new video tracks in Liquid 6), I believe the problem must lie not in the video files themselves - which seem to play with correct blackness on other computers, though I have not had chance to fully test this - but within my computer playback.

    Is this a codec thing? Anybody shed some light as to what is going on?

    Source media is Firewire-captured DV.
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  2. This sounds like a video overlay issue to me. There are separate controls over brigtness, contrast, color, gamma etc. for video overlay and they may be set differently than the desktop's settings. But only one program/window at a time can use video overlay. I suspect what's happening is sometimes the program is getting overlay and sometimes not -- hence the difference in appearance. Most media players can be configured to use overlay or not.

    This can also be a codec or software issue. Some codecs or software will automatically contrast stretch when converting from YUV to RGB for display on the desktop. Some will not. In YUV video, a brightness of 16 is considered full dark and a brightness of 235 full bright. RGB in the computer world uses 0 for bull dark and 255 for full bright. Some codecs/programs stretch the range from 16-235 to 0-255 when converting from YUV to RGB. Others leave the range intact. When using video overlay the video is left in YUV form and the graphics chips convert to RGB for display.
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  3. Member edDV's Avatar
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    Mar 2004
    Location
    Northern California, USA
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    Or it could be more fundamental, if it shows in the finished product, not just the preview.
    http://pro.jvc.com/pro/attributes/prodv/clips/blacksetup/JVC_DEMO.swf
    Recommends: Kiva.org - Loans that change lives.
    http://www.kiva.org/about
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