Many films and series, especially documentaries, include archival footage in their editorial process. Netflix does not have any creative constraints on aspect ratio, but technical errors should be resolved. This article provides best practices for identifying and fixing aspect ratio issues in archival footage during post-production.
Sometimes filmmakers working with archival footage have a clear path to its origin.
If you know the original format of your media, it should match the aspect ratio of the digitized version you are using. For example, Super 8mm is shot in 4:3 aspect ratio, so if you know your original is Super 8mm, and the digitized file is also 4:3, you can be confident that the correct aspect ratio has remained intact after digitization.
If you don’t know the original format of your media, or if your digitized version has been through many different conversions before you received the media, determining the original aspect ratio may be challenging.
For example, if you download a file from an archival web site or receive it from a private home video archive, there may have been mistakes that altered the proportions of the aspect ratio before you received the file.
Unfortunately, it’s not common for archival-heavy projects to have clear information or access to the original format of the media they are working with.
To avoid stretched, squashed, skewed and distorted archival footage in our projects, we’ve created this resource to help partners establish a clear game plan when leveraging archival footage and be able to create their best work.
BEST PRACTICES FOR EDITORIAL
- If you don’t have the original, assume what you have is wrong.
- Check your resolution and your Pixel Aspect Ratio (PAR). Some older formats will have non-square PAR (for example NTSC had 0.9 PAR & HDCAM had 1.3 PAR)
- Trust your eyes. If it looks wrong to you, it will also look wrong to the audience.
- Look for alternate versions of your archival, especially of famous events.
- Watch your entire project at the end specifically looking for archival aspect ratio errors.
- If your archive sources have edges that fluctuate slightly, consider using a standardized matte, mask or output blanking to create a unified look. (See Example 3 in the Visual Examples section)
- Try squeezing/stretching your clips. Often, a clip looks fine at first, but then after a quick squeeze/stretch, it becomes apparent that adjustment is needed.
- Look out for stretched/squashed text or common objects (ex. A street light that’s not circular, a road sign where the text font seems elongated)
- If you downloaded your media from an archival website and it seems like the aspect ratio is incorrect, reach out to a representative from that archive to see if there’s more information.
- Flag anything that looks wrong to the Post Supervisor.
- Sometimes aspect ratio changes will be very subtle, but they are still worth doing!
ROLES AND RESPONSIBILITIES
Whose job is it to fix archival aspect ratio errors?
The Post Supervisor is ultimately responsible for making sure that all aspect ratio errors have been fixed before submitting the final project for delivery.
Assistant Editors & Offline Editors should fix aspect ratio errors when they find them. We recommend watching the entire project from beginning to end specifically to look for these errors. The Offline Editor is responsible for framing decisions and should fix any archival that is skewed or stretched before turning over the project to finishing.
Online Editors, Colorists, Creatives and anyone else watching the project that notices an aspect ratio error should notify the Post Supervisor or Offline Editor.
The QC Operator isn’t responsible for flagging aspect ratio errors. Operators will sometimes flag errors if they notice them, but they often assume the aspect ratio is creative intent. Never rely on your final QC to catch nuanced imaging issues.
If you aren’t sure if something has the wrong aspect ratio, you can reach out to your Netflix post managers and production technology managers.
VISUAL EXAMPLES
Example 1
Before (squashed) Corrected
Example 2
Before (stretched) Corrected
Example 3
Before (visible varied edgeline)
Corrected Version A - 4:3 in 16:9 container, zoomed in a small amount within a 4:3 matte to eliminate the varied edge line for visual consistency (creative choice)
Corrected Version B - Zoomed in to fill the 16:9 frame (creative choice)
BEST PRACTICES FOR DELIVERY WITH MULTIPLE ASPECT RATIOS
While color grading a project with multiple aspect ratios in DolbyVision, set your L0 metadata to the largest aspect ratio used. Make sure you adjust your L5 dynamic aspect ratio metadata on all other shots. Avoid positive lift levels more than 0.025 on letterboxed or pillarboxed shots.
For more information see:
Additionally, having multiple aspect ratios in your final IMF might have an impact on how your project is displayed on different devices. Netflix encoding is based on the largest active picture area of the content, so if some of your shots are taller or wider than the rest of your footage, the encode may introduce letterboxing or pillarboxing.
For example, if your project is mostly 2:1 (3840x1920) but some archival footage is 4:3 (2880x2160) then your final encode will be UHD 3840x2160 to accommodate both aspect ratios. Your 2:1 shots will be letterboxed and your 4:3 shots will be pillarboxed.
Related QC Error Codes: