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DNxHD LB. What’s in a name?

Friday, October 21st, 2016

dnxhd.jpg

You read that correctly. DNxHD LB. I came across this a few weeks back when working with R3D footage and Redcine X Pro and thought there was an error in the menu nomenclature for creating DNxHD 36 proxy media as seen here:

rcx-dnxhd.png

After generating a test file to ensure it was DNxHD 36 (and it was), I started checking into why RedCineX Pro was using this naming convention seeing as “DNxHD_data rate” has been the norm since DNxHD was first released in 2004 (DNxHD 36 was released in 2007). With a little digging I found out that Avid is changing how the codecs are referenced and eliminating the data rate from the name and asking third parties to make the change. So now you have:

  • DNxHD LB (36, 40, etc.)
  • DNxHD SQ (115, 120, 145, etc.)
  • DNxHD HQ (175, 180, 220, etc.)
  • DNxHD HQX (175x, 180x, 220x, etc.)

I can understand why DNxHR has these labels as the codec can scale from 256×120 to 8192×8192 when using custom project sizes:

mc-project-size.png

And when combined with the different frame rates of 23.976, 24,000, 25.000, 29.970, 30.000, 47.952, 48.000, 50.000, 59.940, 60.000, the data rate (and storage calculations) can be a matrix of hundreds, if not thousand of combinations. DNxHD had a little confusion associated with it as the data rate changes with the frame rate and is part of a family: 145 and 220 whereas 36 was just named that as it was only available to progressive projects.

The challenge will be getting everyone on board with the new naming conventions in a timely manner and ensuring it does not lead to misunderstandings and wrong media being created when requesting a certain format, especially in a dailies situation. Since Avid did not make the naming change when DNxHR was released for DNxHD as well, and was marketed as a 2K+ type codec, users have different understandings of what DNxHR is and what to ask for. For example, you can create a custom 1920×1080 project which only allows for DNxHR to be created, and it will be the exact same data rate and storage as DNxHD but the media will not play in earlier versions of Media Composer (pre-Media Composer 8.3 introduced in December 2014) Also, Avid’s DNxHD/HR landing page does not really refer to the new nomenclature either (also does not mention a key benefit of DNxHR HQX supporting 12 bits):

(click for larger image)

avid-dnxhd-page.png

The only other application that I have found that uses the new nomenclature to date (there may be others) is Premiere Pro when selecting for sequence presets for example:

(Click for larger image)

ppro-sequence-presets.png

And in Adobe Media Encoder:

adobe-media-encoder.png

Although the above is a good example of why mistakes might happen. By asking for, or referring to the codec by the shorthand “DNX LB” a user might create either DNxHD LB or DNxHR LB. In the above (very long menu) I would recommend they at least call it out by the full name “DNxHD LB”.

Ironically enough, even the latest version of Media Composer does not refer to DNxHD (LB, SQ, HQ, HQX) in its own transcode UI interface and why users might mistakenly think they are different:

dnxhd-menu.jpg

DaVinci Resolve still uses the DNxHD (36, 40, etc.) names, and then other third parties just use their own naming conventions like EditReady:

dnxhd-from-editready.png

So as Avid takes this phased approach with codec naming, be explicit about which DNx codec you are referring to; HD or HR and know what LB, SQ, HQ, and HQX map to when working with applications that have already changed over to the new naming convention.