FORUMS: list search recent posts

AMA-Transcode Challenges: Color/Luma banding and fixing

COW Forums : Avid Media Composer

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Ed Torr
AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 10, 2017 at 9:47:09 pm

Here's our situation: We're looking at multiple shows that were ingested and edited based on an AMA-transcoded media. i.e. Footage was brought in AMA, then transcoded to Avid media, editing based on the transcodes.

That got the team through offline, but now that we're in Finishing we're seeing significant banding and artifacting on much of the footage. The artifacting is not on the original footage. The problem does not seem to be the result of the resolution chosen for the AMA transcodes; no matter how high we go with the resolution, we still get banding and other artifacts.

The clips in question all originated from ProRes files, brought in via AMA and then transcoded to DNxHD.

The banding issue was resolved as follows: Instead of AMA-transcoding, we import the same ProRes source files via traditional Avid importing and choose "preserve original resolution" from the popup you get when importing ProRes sources. Ingested this way the clips look great. Even when layers are added on top of the footage and rendered, exported, etc. the quality is excellent.

So the challenge we're now facing involves re-importing all the ProRes footage and manually cutting it over the existing AMA-transcoded footage across all offline-edited shows.

Unfortunately that's most of our edits across multiple episodes.

To add insult to injury AMA-transcodes seem to be oblivious to the full OS file paths their source footage -- lost presumably during the AMA transcoding process; all we know are the original file names.

And the source files themselves are scattered across multiple folders, down various convoluted folder hierarchies.

So some questions:

- Is there some way of easily listing the original full file paths from the AMA-transcoded master clips? Is that info hidden somewhere. We've checked all the bin columns and so far come up with nothing. Maybe there's something further we don't know about.

- Is there some existing way of batch re-importing into master clips that were generated by AMA transcodes? I'm not aware this is possible, but hoping against hope.

- Is there some way of replicating the "preserve original resolution" option that auto pops up when importing. I'm not aware of a similar option available to AMA transcoding, but again, hoping against hope.


Return to posts index

Trevor Asquerthian
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 11, 2017 at 10:51:21 am

Is this 4K masters transcoded to HD?



Return to posts index

Ed Torr
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 12, 2017 at 2:54:45 pm

HD-only.


Return to posts index


Glenn Sakatch
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 11, 2017 at 5:00:40 pm

I'm assuming you didn't keep a copy of your original - pre transcoded- ama links? They will show you the original file path. Actually, I thought that if you called up the file path column for a transcode, it would show the original file path from the ama link...maybe that was information I've copied and pasted into a new column at some point, but I'm sure I've accessed it before...hard to remember when its not your project or workflow.

I always keep the ama links somewhere in the project. That way you simply have to bring those links back online, and relink the sequence to those files in Avid.

Maybe check your attic for an old version that still has the links.

Worst cast scenario, you create new ama links to all those prores files...all of them, not just what was used. Put them into a bin or two or three if the bins are getting too large.

Then do sequence relinks to those bins. If the original links and transcodes were all done in Avid, it should be a pretty simply relink job.

Glenn


Return to posts index

Michael Phillips
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 11, 2017 at 7:32:53 pm

If ProRes sources, you should be able to consolidate and not go through a decode/re-encode process. Also, make sure that there is no LUT being applied as some LUTS seem to cause banding when transcoding.

Michael


Return to posts index

Ed Torr
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 12, 2017 at 2:51:58 pm

Unfortunately we inherited the project structure. I suspect the AMAs are somewhere, in a different project the assists prepare everything in, where they are in a bin inside a folder of a folder of a folder, differently from episode to episode. So the challenge is actually to get all this up and running in less than a day without asking the assistants help because they are "too busy and stretched way too thin". They're called "AE" because once upon a time they assisted editors, but now they assist post producers, and APP is already being used by Apple.


Return to posts index


Glenn Sakatch
Re: AMA-Transcode Challenges: Color/Luma banding and fixing
on Nov 12, 2017 at 5:10:13 pm

using the "alt drag" method, you can probably rebuild all your links in pretty quickly.

ALT drag (from the finder or explorer) a folder containing your subfolders with media into a bin and release.
This should create new ama links which your can then relink your sequences to.

Glenn


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]