Latest post Tue, Oct 3 2017 5:38 PM by Tom Swartwout. 7 replies.
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  • Thu, Sep 28 2017 1:37 PM

    DNxHR in an HD project

    Looking for some advice.  I'd like to use the DNxHR HQ 12 bit codec in an HD project.  (We use Resolve to transcode our various 4K/6K/RAW/etc footage to HD for editing in Media Composer.) 

    I'm unable to select an HR resolution in the Media Creation setting, nor am I able to export a quicktime "same as source" that doesn't change the file to DNxHD.

    I did read that the HR codec is limited to custom or higher than HD resolutions projects, but I'm wondering if there is a work around or if Avid has plans for changing the current limitations?  It would seem that some of the benefits of the HR codec might be of use to everyone, no matter what the frame size?

    While I'm asking these questions, here are a few more:

    The file sizes for 1920x1080 10 bit DNxHD and 12 bit DNxHR are the same.  That must mean more compression is happening for the 12 bit file?  I'm out of my depth here, no pun intended (horrible).

    The color space information for the DNxHR 12 bit files says this: YCbCr [256-3760 (16 bits)].  Anyone able to provide some insight (is this an indication of how Media Composer handles color correction)?

    Thanks,

    Tom

     

    MC 2018.12.3 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.4/32GB RAM/GTX 780M 4GB/ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Sat, Sep 30 2017 3:40 AM In reply to

    • tpowell
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    Re: DNxHR in an HD project

    For your first issue, have you tried changing the project format to a suitable/similar 4k format? You should have the HR options for importing or exporting. You can then change the format back to HD for working on the project.

  • Sun, Oct 1 2017 4:20 PM In reply to

    Re: DNxHR in an HD project

    Thanks.  I did try that - it doesn't seem to work the way I'd like.  If I'm importing HD, or rendering, or exporting HD, while in a UHD project for instance,  Avid "knows" and only presents the DNxHD options. 

    One thing that is kind of interesting - but not what I need right now: if I AMA link and transcode in an HD project and select "keep source's frame rate, I am provided the HR options. 

    MC 2018.12.3 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.4/32GB RAM/GTX 780M 4GB/ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Sun, Oct 1 2017 4:58 PM In reply to

    • jef
    • Top 50 Contributor
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    Re: DNxHR in an HD project

    Tom Swartwout:

    One thing that is kind of interesting - but not what I need right now: if I AMA link and transcode in an HD project and select "keep source's frame rate, I am provided the HR options. 

    I am curious as to why the "Keep Sources's fame rate / AMA link / transcode to HR" is not a good option for you?

    And not understanding your full workflow, I am wondering why you seem to want to avoid "classic" DNxHD when the frame size is just HD?  Seems like we don't know exactly you are trying to achieve.

    Is it that you believe DNx HR is a "better" codec than classic DNx?  If so, I do not think that is the case.  As I understand things (and I may be wrong) DNxHR was developed to solve some limitations of classic DNx.  Specifically frame size, frame rate and bit depth for HDR.

    As to the data rate being the same for 8 /10/12 bit media.  You are correct that media being compressed more when you have a higher bit depth.  I worried about that when DNx first came out.  But I got over it.  Big Smile

    Jef

    Avid DS 11.0.2 R.I.P | MC "Well, it depends ..." mostly 8.10.0 but playing w 2018.11| OS 10.11.x - various MacPro Towers - home system MacPro... [view my complete system specs]

    _____________________________________________

    Jef Huey

    Senior Editor

    Old Stuff  http://vimeo.com/album/3037796

  • Mon, Oct 2 2017 8:32 PM In reply to

    Re: DNxHR in an HD project

    Hi Jef,

    Why not AMA link/transcode to HR?  We've chosen to use Resolve to transcode the material because it transcodes faster and seems better at handling a lot of footage from multiple cameras, frame sizes, frame rates, codecs.   For some of our projects we match back to the camera original material and color correct from within Resolve - the roundtripping has worked well for us.   

    Why HR vs HD?  The extra bits - 10 vs 12 bit.  I noticed that it has helped with some issues of banding.  Anyway, I'm just beginning to explore whether the extra bits are something we might want to take advantage of.  Possibly we'll stick to the tried and true for now - or we'll transcode to HR and I'll not sweat the codec shift from HR to HD for renders and export.

    Thanks for the help,

    Tom

    MC 2018.12.3 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.4/32GB RAM/GTX 780M 4GB/ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Tue, Oct 3 2017 6:03 AM In reply to

    • tpowell
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    Re: DNxHR in an HD project

    Hi Tom. I am on 8.9.2. That is not how mine works. I have an HD project, with most of the material HD, and some 4k. When my project format is HD, I only get the DNxHD options for importing. When I change the format to 4k in the same project, I get the DNxHR options and ProRes options. This works on HD or 4k footage. Changing my project format back to HD allows me to see the HD footage as native, and the 4k shots as frameflex modified, but they all play real time. If I change the format of the project back to 4k, The 4k shots now show up as native, and the HD shots show up as Frameflex. Same thing if I AMA link and select transcode. The flavors I get are aligned with the current project format, rather than the size of the source clip. As I typically deliver for broadcast on HD, I haven't experimented with the export options. Anyway, sorry I couldn't help.

     

  • Tue, Oct 3 2017 1:03 PM In reply to

    Re: DNxHR in an HD project

    Ahh.  I thnk I get it.  I had assumed, maybe incorrectly, that if I worked within a 4K format, then all of my HD sized shots would be uprezed via frame flex - but maybe that's not the correct way to think about it.  I'll get back to you as I check my exports later today.

    MC 2018.12.3 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.4/32GB RAM/GTX 780M 4GB/ARECA 8050/Sony 1080p HDTV [view my complete system specs]
  • Tue, Oct 3 2017 5:38 PM In reply to

    Re: DNxHR in an HD project

    It would seem (and it makes sense) that the exports and rendered files are always going to match the project format - so unfortunately I can't use the HD format and keep the HR 12 bit codec.  

     

     

    MC 2018.12.3 with Symphony Options/iMac Late 2013 i7/Mac OS 10.14.4/32GB RAM/GTX 780M 4GB/ARECA 8050/Sony 1080p HDTV [view my complete system specs]
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