Final Master for Archiving


(Mauro Moreira) #1

Hi, i`m planning to archive a tv series that used the ACES pipeline.
The best way is to export an EXR (no compression) master with no ODT? So I can use other ODT when delivering to another format/color space?

BTW: For grading we used the 709 ODT.

Thanks,


(Walter Arrighetti) #2

Hi Mauro.
Correct: currently, the best way for archive an ACES-based production is saving in OpenEXR sequence of frames compatible with the SMPTE ST2065-4 standard, that is roughly:

  • OpenEXR file format;
  • RGB or RGB+alpha, 16-bit/channel floating point codevalues
  • No compression;
  • Color encoding in ACES2065-1 color-space (thus no burning/rendering any Output Transforms);
  • filling up ST2065-4 compulsory metadata fields in the OpenEXR header (e.g. acesImageContainer = 1).

The reasons why this is the best encoding is future-proofing the color of the picture and making it independent of a particular display technology (like the Rec.709 monitor you have likely mastered the content today).
Use of a file-per-frame format (instead of an MXF-wrapped standard like, for example, ST2065-5) is preferred for archival due to several operational reasons.


(Jim Houston) #3

Just adding that no RRT either, so no RRT/ODT lut to be baked into the data. Just the color grade.
Though it is a pain from a storage size, many people are saving the ungraded ACES files (effectively the same as the original camera files) as well as the graded ones. But that just goes along with the philosophy of archiving of having at least two (maybe three) copies for digital assets to be considered Safe.


(Mauro Moreira) #4

Thanks for your reply Walter. Im a bit confused with this metadata. Im using Davinci to master, is there a option in Davinci or do I need to use another tool?

Thanks,


(Mauro Moreira) #5

Thanks Jim!
I think in Resolve the RRT is “embedded” with the ODT, right?

Thanks,


(Walter Arrighetti) #6

Hello Mauro. Most software rendering ACES would just write uncompressed, 16bpc EXR files without even creating the acesImageContainer field. Despite there isn’t any quality difference (i.e. same codevalues), those would not be ST2065-4 ACES files.

ACES Product Partners, however, should be capable of honoring those metadata when creating ACES-compatible EXRs with their products.


(Jim Houston) #7

That’s right ,