Latest post Tue, Nov 13 2012 7:00 PM by The ARSENO. 6 replies.
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  • Tue, Nov 13 2012 3:33 PM

    • The ARSENO
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    DSLR workflow for color grading

    Hi everyone, 
    I am sure there are a lot of posts about DSLR workflow on Avid, but I couldn't find one that answers my simple questions.
    I am pretty new to Avid Media Composer, I've just switched to it after Premiere, and my question is the following.
     How shall I import DSLR H264 files to Avid MC 6 letting their color space to stay full swing 0 - 255 and not 16 - 235 ?
    The media will not be broadcasted and it is only for web playback. Any changes needed I will do later in Resolve so I wont to have the 0 - 255 to have the biggest room to play with the levels.

    Please explain step by step as I am new to Avid and please tell me which versions of DNxHD to use, shall I convert the H264 files before importing with mpeg streamclip or not?

    Basically I want to find out a workflow which will allow not to lose any quality during encoding and color grading.

    Thank you very much in advance.

  • Tue, Nov 13 2012 3:40 PM In reply to

    Re: DSLR workflow for color grading

    IF you AMA link the files into MC you can use the menu option set Source Settings to look at the levels (against a histogram with 16-235 indicated by white lines) you can then choose to apply eitehr compression, expansion or leave as they are to the levels.

    But which DSLR are the fiels from? The newer 5D mkIII now produces rec 709 levels (16-235) where as the earlier ones where full swing.

    Also MC is designed to work for TV formats so is based on 601/709 workflows. You can make it take footage at full swing levels 0-255 but you will have issues. Att a white title with black shadow and the shadow will be at 16 and the white at 235. The black filler will be at 16 etc.

    So the workflow woul;d normally be to bring the levels to 16-235 (if they aren't already) and work in that space. When you finally export at the end you can expand back to full swing levels if you need them.

    Yes there is re-mappng going on but compared to he horrid H.264 compression and the 4:2:0 color space it's a small issue.

     

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  • Tue, Nov 13 2012 3:57 PM In reply to

    Re: DSLR workflow for color grading

    Yes, there is nothing you can do about the "horrid" H264 compression, but there is something you can do about the even more horrid banding you get if you cocatenate 8 bit material, with grading, dissolves and any process that alters pixel levels.

    I recommend that you transcode to a 10 bit codec like DNxHD185X (25p), especially if you are going to remap the levels when you transcode the AMA linked media as Pat suggests.

    Export to Resolve same as source to maintain the bit depth.

    Symphony 7.06 OS 10.9.5 QT 7.6.3 Mac Pro 2x2.66 6-core 32GB Ram Aja Kona Lhi. MC 7.0.6 OS 10.9.5 Mac Pro 5.1 2x2.97 6-core 32GB ram Aja I/O express, Apple... [view my complete system specs]
  • Tue, Nov 13 2012 4:37 PM In reply to

    Re: DSLR workflow for color grading

    Don't forget if you ever go back to 8 bit from the 10 bit you will fall back into the banding issues.

    Also that DNX185X has a higher comrpession ratio than just DNX185 so that may have an impact.

    We tend to find the DSLR footage cope ok if the exposures close during the shoot but if it needs re-working in the grade by any real degree it just falls apart.

    We also strangly repeatedly have issues dong Achemist frame rate conversions on 5D and 7D footage.

    Not sure what causes the issue, it maybe the temporal H.264 codec but the Achemist frequently drops down into blended mode and the results look poor.

    ACI Moderator. I'm not employed by Avid or work for them. I just do this in my spare time. Normally using the current Media Composer version on My... [view my complete system specs]

     

    Broadcast & Post Production Consultant / Trainer  Avid Certified Instructor VET

     

    QC/QAR Training - Understanding Digital Media - Advanced Files * Compression - Avid Ingest - PSE fixing courses and more

    All bespoke and delivered onsite at yours. Or delivered via hostred Zoom session.

     

    T 07581 201248 | E pat@vet-training.co.uk | W www.vet-training.co.uk |

     

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  • Tue, Nov 13 2012 6:34 PM In reply to

    • cuervo
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    Re: DSLR workflow for color grading

    hmmmm....

    here's my workflow:

    1-Convert native AVCHD into DNx185x via Adobe Media Encoder. Be sure to set items under "Interpret Footage" correctly.

    2-Fast Import converted files to MC with 601/709 levels. This leaves the levels unchanged. NEVER, ever use AMA!

    3-Apply a 'knee' with CC tools to legalize imported footage.

    4-Apply FX.

    5-Mixdown final footage and convert to "full swing'. Export at 601/709.

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  • Tue, Nov 13 2012 6:35 PM In reply to

    • The ARSENO
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    • Joined on Sun, Nov 11 2012
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    • Points 95

    Re: DSLR workflow for color grading

    Thank you so much for your help, but I want to be sure about the workflow. So I transcode to DNX185 via AMA, make the colors 16 - 235 (I use 550D which is 0 - 255) and on export I use the same DNX185 10 bit codec after which I grade that in Resolve and this is the best way of keeping the quality loss on minimum ?
    I have read on some posts that AMA automatically makes H264 footages to be 16 - 235 anyway, even if you chose not to do it. So may be I just transcode with mpegstreamclip to DNX and then use just simple import choosing RGB ?

    Sorry if the questions sound stupid, I am very new to Avid.
    Thank you in advance. 

  • Tue, Nov 13 2012 7:00 PM In reply to

    • The ARSENO
    • Not Ranked
    • Joined on Sun, Nov 11 2012
    • Posts 7
    • Points 95

    Re: DSLR workflow for color grading

    Thanks for sharing the workflow cuervo. So as I understand on the step  2. I choose YCbCr 709 instead of RGB ? 

    And what exactly does it mean to convert to "full swing" ?

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