Why resolution independence is an illusion

By The Unknown Artist

All professional editorial systems now advertise “resolution independence,” and in some cases “frame-rate independence.” Avid was the last major player to the party around Christmas of 2014, cautiously launching resolution independence through its AMA.

Resolution independence really doesn’t mean much. It’s simply a little bit of code that automatically resizes all your source material to fit the frame size you’re working in. Frame-rate independence is a much bigger issue, however, because of what it means and what each
system does to the material to make it happen.

Frame-rate independence means that if you’re working in 23.98fps, you can throw in a clip that’s a different frame rate, such as an SD clip at 29.97fps. This is something that Final Cut Pro has always allowed, Adobe Premiere has sort of allowed (using the “Interpret Footage” function) and Avid has recently written into the software.

The truth is, there’s no such thing as the ability to mix frame rates in a project. No matter what system you’re using, if it is running moving images it has to have a set speed for playback. That speed can’t be variable, so all of your clips will always have to be in some way converted to the frame rate of your sequence.

Online/color systems like DaVinci Resolve handle alternate frame rates by treating one frame as one frame. Frame-for-frame conversions make the clips play at a different speed and can cause gaps in the sequence. FCP 7, FCP X, Premiere and Media Composer automatically speed-change these clips to play at the right speed for sync.

Avid allows you to play frame for frame if you change the playback rate in Source Settings — this effectively interprets the footage differently before you cut into the sequence. Your clip will play smoothly but at a different speed based on the new frame rate. The speed change method used in FCP 7/FCP X either drops or adds frames to the clip, making it stutter. Avid does the same until you render or transcode. In Avid you can set it to use fluid motion if you don’t mind using a lot more render power.

Interlacing
Interlaced footage is a bigger problem these days if you’re mastering for file-based delivery. Computer screens and many television sets only play progressive. Most of the time your GUI won’t ever show you the problem… until you start exporting or mastering. Interlacing works by playing half the frame at a time, slightly offset. This is why if you convert it without de-interlacing, and your speed change calculates that you’re hitting a certain frame a fraction of the way through it in terms of time, you’ll see jagged lines. This is an issue as old as 3:2 pull down, and “frame-rate independence” does not fix it.

People criticized Avid for being the last to introduce frame-rate independence. I believe the reason they withheld is because Avid has always been a system that forces the editor to work, in my opinion, “correctly.” FCP was the first to allow someone to edit without understanding frame rate and why it needs to be consistent. People got used to being able to throw anything into any timeline and began to question why it wasn’t standard.

In reality, frame-rate and resolution-independence aren’t really what the companies say it is. Our software just does those conversions for us. If we stop being mindful of this, I worry that we will end up with inferior end products out there in the market.

Some systems do a better job of scaling and speed changing than others. Writing in the least-intensive workarounds to the code of our NLEs means they’re not considering the best conversion methods and trying to make us (or more importantly, our producers) forget that conversions are necessary at all.

To Sum Up
Independence of resolution and frame rate is an illusion. It’s a meaningless buzzword that enforces more of the bad habits that creep into our industry.

It’s a good thing for those who don’t have any technical knowledge — or just aren’t interested in the technology — allowing them to be creative without having to understand time, pixels and signals. But for the more technical professional, it’s essential to know what’s under the hood of our NLE systems, files and clips. We must maintain a constant awareness of workarounds and illusions like “independence” at every step of our workflow, to ensure we keep putting out the best possible images.

The Unknown Artist is a post-production professional by day and The Unknown Artist by night. Enjoy this semi-regular column, and send topic ideas and questions to theunknownartist@postPerspective.com.

3 thoughts on “Why resolution independence is an illusion

  1. Jonathan Moser

    Thanks for clarifying the “late to the table” legacy of Avid…they’ve gotten a raw deal because everyone else took shortcuts that wound up costing productions more time and headaches in “fixing” things that shouldn’t have happened in the first place. But until Apple took their stumbles and missteps, Avid editors had to take a lot of heat for still editing on “grandpa’s machine.” Great article.

    Reply
  2. The Unknown Artist

    People know that taking shortcuts in a production means that it will likely increase costs later in Post: but when NLE’s add these shortcuts as a sort of “default” working state, we have to stay vigilant and aware of the repercussions, I think!

    Reply

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