Latest post Sat, Jun 6 2015 5:28 PM by Vincent Steenmeijer. 2 replies.
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  • Sat, Jun 6 2015 11:50 AM

    What is the best AMA transcode workflow for Sony XAVC files

    Hi all,

    Need your advice. I'm starting a project with XAVC files (MXF) shot on 1080p/50FPS. To get the best performance out of my system I'd like to transcode the files tot a lower resolution, then edit with these transcoded files,  and then relink the edited sequence back to the original MXF files for online use (viewing/grading)

    I've set up a test to see if all goes well. It doesn't...

    First of all, when I want to transcode the files to DnXHD 85, it will only do so if I convert the files into 25FPS. For the offline edit this fine for me, but I think it might disable the possibility to relink again to the original MXF files?! I tried to find a project format with 50FPS, but couldn't find any. So I decided to transcode/convert to 25FPS and edited a small sequence with the transcoded files.

    Then I duplicated the sequence and tried to relink to the MXF's. It didn't work.

    I'm working on MediaComposer 8.3.1. What am I doing wrong? Please advice.


    MacBook Pro Retina (late 2013) MediaComposer 8.3.1 [view my complete system specs]
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  • Sat, Jun 6 2015 1:01 PM In reply to

    Re: What is the best AMA transcode workflow for Sony XAVC files

    Haven't worked with the exact format you're working with (which flavor of XAVC?  I haven't worked with any form of XAVC yet either way) - is it one that you can CONSOLIDATE?  That would be a quick process, you just keep the full resolution of your video as it's essentially a copy, and your system will perform better with the new Avid-native media.

    That aside, about transcoding and framerates - 

    The main rule is, as soon as you change the framerate of video, you break the ability to relink.  Yes, even 50fps to 25fps.

    But changing resolution does not break a relink.  Before 8.3, I'd generally switch my project to 720p50 (isn't this available for you?), do the transcode (I forget the exact DNxHD datarates available in 720p50 as I work in 29.97 and 59.94), then either switch back to 1080p and keep editing, OR just edit in 720p for a while.

    Now in 8.3 (note, this workflow MIGHT become simpler in 8.4 from what I've seen posted, more on that later), you can also switch to UHD50p - why would you do that?  Because with DNxHR, you have new resolution-transcode options.  You can transcode at the project res (UHD), BUT ALSO at the footage source res (you get 1080p50 DNxHR, then), or you can even even use the low-bandwidth DNxHR-LB option at 1/4 or 1/16 source res (540p or 270p - but treated like 1080p in the timeline).  I really like the new 1/4 and 1/16 options for offline/multicam editing, and it seems to me they also transcode MUCH faster than anything else.  I also like DNxHR better than something like H.264 proxy because you CAN QT-Reference them for a low-res preview.  That's what's so great about DNxHR - you can do the whole edit/export process in source or proxy resolution, saving space, and it's easy to relink to your sources.

    Once you get the transcode going, you can then immediately switch your project back to 1080p - and then relink whenever you need/want, instantly - put all AMA in one bin (or set of bins), put all DNx in another bin or set.  Open each one as needed, select all the source clips in it, then relink your sequence(s) to "selected items in all open bins."

    As I understand it, some of these new transcode possibilities may filter down into HD and smaller project types in 8.4, I'd seen that posted elsewhere on this forum, I forget exactly where.

    In all cases, my rule is ALWAYS keep the source framerate.  In mixed-rate projects, transcode to source rate, and use motion adapters.

    (SYSTEM 1) iMac Late 2012 27" (13,2), Mac OS X 10.15.5, Avid Media Composer 2020.6 w/Symphony, Intel Core i7 3.4 GHz, 32 GB RAM, NVIDIA GeForce GTX... [view my complete system specs]
  • Sat, Jun 6 2015 5:28 PM In reply to

    Re: What is the best AMA transcode workflow for Sony XAVC files

    Thanks for your great input. Much help. I got the roundtrip working after I started not with a 1080p25 project, but with a 1080p50 project. Doing so it allowed me to transcode in the same framerate. And thus relinking to the original MXF files (XAVC Intra 100 by the way).


    MacBook Pro Retina (late 2013) MediaComposer 8.3.1 [view my complete system specs]
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