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HD + 4K workflow suggestions

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Jesenko Fazlagic
HD + 4K workflow suggestions
on Nov 8, 2013 at 3:40:22 pm

Hi all,

We are testing a new workflow for long-form shows which will combine HD footage from various cameras with some 4K footage from the Sony F55.
The 4K footage will be greenscreen interviews so the FrameFlex function in MC7 will allow us to cut between CUs and wides with footage from a single camera. Great, works well in AMA-linked media tests and keys just beautifully.

So now, we need an offline/online workflow which entails transcoding all the footage to DNx36 for edit, and then relink/transcode to DNx175X for online.
In our tests we are able to apply FrameFlex to the 36 media in offline (clips show up with a green dot even though they are 1080 at that point) and it translates to 4K AMA clips when relinked. Again, great.

Finally, now that we need to transcode to 175X for online, the question is - what to do with the 4K clips?
Leave them AMA-linked and make sure they are accessed from a fast drive array? It's doable but it entails a LOT of footage from a lot of shows. Not very practical.

Transcoding them seems to just create a 1080HD file which has the FrameFlex effect on it but is actually just pushing in on the shot past 100%.
We see the new transcoding option "Apply reformatting/color option" but checking it didn't seem to force the cropping of the shots per FrameFlex settings.

Now that MC7 manages the AMA media, is there a way to consolidate the 4K media in a way to preserve the resolution? Basically to do an "AMA Consolidate"? Our tests again show the footage being consolidated only as 1080HD.

Somewhat new territory here, all input is very much welcome. Thanks!

//Jesenko


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Michael Phillips
Re: HD + 4K workflow suggestions
on Nov 9, 2013 at 10:02:45 pm

The final output will always be 1920 x 1080 since that what Media Composer tops out as. The workflow you lay out is the workflow you will use. The FrameFlex metadata will be applied to the camera originals the same way t was the first time and instead of DNxHD 36, you will select a finishing quality - most likely DNxHD 175x or perhaps RGB 444 project type. The regions of interest extraction will be the same. If you want to keep the AMA link "live" during the online conform to be able to change things, then that is a different issue. The XAVC 4K files should be able to play back (scaled to HD). SONY RAW may be another matter.


Michael


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Jesenko Fazlagic
Re: HD + 4K workflow suggestions
on Nov 11, 2013 at 6:14:33 pm

Thanks for your input Michael.

Makes sense, but how about this question:
"Transcoding them seems to just create a 1080HD file which has the FrameFlex effect on it but is actually just pushing in on the shot past 100%.
We see the new transcoding option "Apply reformatting/color option" but checking it didn't seem to force the cropping of the shots per FrameFlex settings."

Was this your experience? I can't see a way to force Avid to actually apply the FrameFlex "effect" and bake a cropped clip in DNx175. It just makes a full raster 1080HD file and pushes in on that, which makes it soft. Am I missing a step somewhere?

Thanks again.

//Jesenko


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Michael Phillips
Re: HD + 4K workflow suggestions
on Nov 12, 2013 at 2:32:09 pm

Anytime you transcode, you are locking yourself into a 1920 x 1080 raster and whatever codec/data rate chosen. The FrameFlex vectors at that point become metadata should you ever go back to the camera original as in an offline to camera original online conform.

If you have a LUT and FrameFlex region of interest on a shot, and you transcode, you should end up with a .new clip that has that baked in to the clip. I will test again to make sure, but that is how it's supposed to work in order to go back to legacy systems.

The only way to get FrameFlex vectors to work at high quality is when live linking to the 2K+ camera original. Also keep in mind that any other VFX that affects image size is always done to the 1920 x 1080 output of the FrameFlex pipeline.


Michael


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Pat Horridge
Re: HD + 4K workflow suggestions
on Nov 14, 2013 at 3:20:21 pm

Yup that's the way it works.
I shoot 1080 on my motorbike helmet gopro but only output 720 for upload to youtube.
I can frameflex in on the 1080 sources and then transcode and bake in without quality loss unless I push beyond the 720 pixels mark. Then the image starts to get scaled.

Pat Horridge
Technical Director, Trainer, Avid Certified Instructor
VET
Production Editing Digital Media Design DVD
T +44 (0)20 7505 4701 | F +44 (0)20 7505 4800 | E pat@vet.co.uk |
http://www.vet.co.uk | Lux Building 2-4 Hoxton Square London N1 6US


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