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8-bit 4:2:2 raising levels in part of image in FCP
If I render to BM 8-bit uncompressed 4:2:2 in After Effects, or capture footage to that codec, then drop it into a matching D1 timeline in FCP 5, something odd happens:
the last 7 pixels (714-720) have their RGB levels raised about 7% or +5 RGB.
On a black clip, this results in a vertical gray band at the right edge of the clip. It’s pretty noticeable if you have to scale down the clip so the edges are within safe.
Clues:
1. If I use FCP to render the 8-bit timeline to Photo-JPEG, the gray band becomes 7 bands alternating RGB 13, RGB 0. That is, four at 13, three at 0. The 13 is approximate, between 11 and 14 RGB. Normally the band is a gray band of varying RGB levels, but not as quantized as this.
2. I see no band when dropping the 8-bit clip into a 10-bit timeline.
3. However, I see the band when dropping the 8-bit clip into a Photo-JPEG timeline.
4. I see no band when dropping an 8-bit 4:2:2 clip into After Effects.
5. I see no band when dropping P-JPEG or 10-bit clips into an 8-bit 4:2:2 timeline.
6. The band shrinks with the clip as it is scaled in FCP.Dual G5 2 GHz, OS 10.4.4, FCP 5.0.4, AE 6.5.1, BM 5.4.2, Decklink SP, QT 7.0.3.
If you need more information, please let me know.
… and if this has been covered elsewhere, please link me up and I’ll be on my way. 🙂Thanks,
Steve -
4 Replies
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Hi Steve,
Thanks for the report and we’ll look into it. Any chance of sending us a frame of the problematic video?
support[at]blackmagic-design.com
regards
Kristian Lam
Blackmagic Design -
Sure, I’ll try to cover a few situations. Would you like me to send you a few frames, along with an FCP project?
Thanks,
Steve -
Hi Steve,
That will help a lot. Thanks.
regards
Kristian Lam
Blackmagic Design -
Did you get my e-mail (with FCP project) on this, Kristian?
Thanks,
Steve
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