INTRODUCTION
The purpose of a NAM is to preserve the final picture of a title in a high quality agnostic format limited only by the original source in order to allow for a lossless starting point in generating future derivative masters. These best practices should serve as a guide to help in meeting the NAM Specifications found in Branded Delivery Specifications: Post Production while addressing most common edge case scenarios.
GENERAL
- It is acceptable for a Non-Graded Archival Master to contain color bars, framing charts, head/tail black, head/tail visible pop for sync, or Academy leaders if any of these are present in the timeline the asset is generated from, however all non-color grade related content from the first-frame-of-action (FFOA) to the last-frame-of-action (LFOA) must match the final/approved IMF.
- If a non-color grade related change in picture is made to the IMF during the process of delivery (such as updated VFX, clean up, graphics or optical work), then the Non-Graded Archival Master asset must be updated to contain that same change
COLOR
- During the DI process, working in a Color Managed framework can help ensure that the NAM is delivered in a single scene-referred color space and avoid any colorspace or transfer function mismatches within the asset, as illustrated below:
- For more information on Color Management, refer to the Image + Color Workflows section.
*as viewed on a display without the proper mapping applied
FRAMING & RESOLUTION
- While NAM must have at a minimum an equivalency to the Streaming Master (IMF)’s Active Picture, more often than not the NAM will be larger than the IMF since it should include any extra captured area, which is often cropped and/or hidden by Active Picture area blanking in the IMF. The Active Picture area is determined by the delivered framing chart.
- Global up-scaling to UHD should not be employed and will result in an invalid NAM.
OPTICAL EFFECTS
Examples of Optical Effects: stabilizations, reframing, removal of production equipment, cosmetic fixes, etc.
- Any effect or fix applied in the online editorial process should be included in the Non-Graded Archival Master (NAM).
- Any effect or fix applied with a color grading process should be excluded from the Non-Graded Archival Master (NAM).
- In the case of reframing, a NAM is valid as long as the image represented in the Archival Master's Active Picture area matches the image available in the streaming master (IMF)'s Active Picture area.
ASSET REVIEW AND CONFIRMATION
Post Vendors often have access to all relevant assets used to create a NAM, from Camera Original Files all the way to the IMF, and therefore are usually best suited to conduct the Asset Review. In the Asset Review the NAM is compared and contrasted against the IMF to confirm that the NAM contains the fully conformed and locked picture, including final VFX. It is also recommended a verification against the Original Camera Files for a color check to confirm that the NAM is rendered in a single scene-referred color space with no output or display transform applied.
After the Asset Review takes place a Checksum Manifest should be generated. The manifest will then be verified by Netflix confirming that no content has been lost or altered during the delivery process. Checksum Manifests should be provided in one of the supported formats:
- Media Hash List (MHL) at the root level of the folder being delivered. The MHL should include entries for all files in the delivered folder. MHL manifests can be generated by a large number of 3rd party or open source tools.
- Checksum.txt in the folder containing the image sequence. Checksum.txt manifests can be generated by Content Hub Command Line (chcli) tools.
Please note that “zipping” of NAMs is no longer required and should not be done.
If you have any questions about Asset Review or Confirmation, please reach out to your Post Production Management or Creative Technologies Workflow contacts at Netflix.
FOLDER STRUCTURE & NAMING CONVENTION
Details on folder structure and file naming for delivery can be found at ‘Picture Archival Assets: Folder Structure and File Naming Convention’.
ADDITIONAL RESOURCES
ACES Deliveries in DaVinci Resolve
CHANGE LOG
10-3-2022
Removed "Requirements" Section and linked to Post Production Delivery Specs v5.0.
11-30-2021
Added "Additional Resources" link for "ACES Deliveries in DaVinci Resolve."
07-15-2020
Updated language around Best Practices for clarification of the language and adding further examples.
12-15-2020
Consolidated Best Practices into this article, adding the "Asset Review and Confirmation" item to that section.
08-06-2020
Updated language around Quicktime Wrapped Non-Graded Archival Master Exceptions to specify that these are the minimum requirements and also to specify different codecs for SDR and HDR.
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