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Qucktime reference set-up level shift
Here’s the workflow that’s causing trouble:
1. Clip is digitized as 1:1 HD or DNxHD
2. Clip is copied to Media Composer software-only system
3. QT reference of the clip is encoded to HD AVC or mpeg2 via MainConcept
4. Resulting encode has lifted blacksWe bring the QT back into Avid, look at it on the built-in waveform, and the blacks ARE LIFTED.
Steps taken to trouble-shoot the issue:
1. The clip is mixed-down or color-effected (with no change in color)
2. Clip is exported as QT reference
3. Clip is re-imported into AvidBlacks are FINE.
BUT…
If that mixed-down clip is encoded with MainConcept or CinemaCraft, the resulting mpeg has… again, LIFTED blacks. Both MainConcept and Cinemacraft do not lift blacks on AVIs from Premiere or QTs from FCP, so the issue is not with the encoders.
However, if that same clip is encoded with ProCoder, blacks are FINE. Unfortunately, we can’t use ProCoder because it does not support AVC very well.
QT version is 7.2 on both the digitizing Avid and the software-only one.
MC version is 2.7.5 on the digitizing Avid and 2.6 on the software-only one.
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3 Replies
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There is something called 601/709 levels.
You probably export as that. Although Qt ref, Avid nowadays can also output RGB levels that most encoders expect.
Some encoders can be told that input is in fact NOT rgb, but (at least with Cinemacraft), this only works well with half Avid’s codecs.
Test, test, test is my only advice.Bouke
http://www.videoToolShed.com
smart tools for video pro’s -
Thanks. I feel like I ran out of tests. Tried both 601 and RGB. RGB looks lifted even in the QT player.
Max
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Author
New York
Area4.tv -
Look for settngs in the encoder that indicate sources are 16-235 or not. if exported as 601/709, check that setting.
Michael
Michael Phillips
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