Runway's Ruby converts AI video to broadcast HDR standards

What Ruby does

Ruby is a tool that converts SDR video into HDR. It works on output from any video model available within Runway, and you can also feed it real, camera-shot footage directly, not just generated clips. The output comes as either 16-bit EXR image sequences, or ProRes/HEVC files carrying PQ or HLG on top of the BT.2020 color space.

Each format serves a different purpose. A 16-bit EXR sequence uses floating-point frames, so it drops straight into editing or compositing tools and can hold up under heavy compositing work — keying, relighting, and the like — just as well as raw camera footage. 10-bit and 12-bit ProRes files sit alongside camera originals in the edit, giving colorists real room to push the grade instead of having to coax it out of an 8-bit file.

Output format	Bit depth	Primary use
EXR sequence	16-bit (half float)	Source files for color grading and compositing
ProRes	10/12-bit (422, 422 HQ, 4444)	Editing and mastering
HEVC	10-bit (HDR10 default, HLG)	Streaming and final delivery

The video itself mentions both 10-bit and 12-bit for HEVC, but the published API documentation lists HEVC output as 10-bit only. Since the two sources disagree here, the table above reflects the documentation.

Real HDR versus SDR in disguise

Where this video actually puts in the work isn't the feature rundown — it's the conceptual explanation. Converting SDR to HDR, Runway says, requires changing three things at the same time.

The first is bit depth. Going from 8-bit to 10-bit or higher quadruples the number of tonal steps per channel, which is exactly what buys you room to avoid banding. When exporting as an EXR sequence, that's 16-bit.

The second is color gamut. Widening from Rec.709 to BT.2020 opens up a much larger range of reds, greens, and blues that SDR simply can't represent.

The third is the transfer function — the rule that maps pixel values to actual brightness. This means swapping out SDR's gamma curve, built around a 100-nit display, for a curve designed for displays capable of 1,000 nits or more.

Skip even one of these three, Runway says, and what you get "isn't real HDR — it's SDR wearing a costume." It's a pointed distinction from results that simply crank up the brightness and call it HDR.

Choosing between PQ and HLG

Even within HDR, you still have to pick one of two transfer functions.

PQ works on an absolute standard. Each pixel value maps to a fixed brightness level, and in theory it can go up to 10,000 nits. To make that work, it carries along MaxCLL and MaxFALL metadata that tells the display "the brightest pixel goes up to here, and the frame's average maximum brightness goes up to here."

HLG, by contrast, works on a relative standard. Brightness is set relative to the scene, and it can be viewed on an SDR display without any extra processing. Because it's relative, there's no need to attach separate static metadata.

How to use it, and how to check it worked

Ruby isn't a separate app — it's built into Runway itself. You can trigger the conversion from Tool Mode, Apps, Workflows, or the Runway web portal, no matter which one you're working in. And it's not limited to conversion, either: the video notes that some of Runway's own models, including Gen-4.5, can generate these file formats natively from the start.

It also explains how to verify that a conversion actually worked. Open the output file in VLC, go to Tools → Codec Information, and check the transfer function field. If it shows PQ or HLG — whichever you selected — the conversion went through correctly.

The published API documentation lays out more specific conditions. The input must be SDR video, no longer than 40 seconds, with each side under 4096 pixels. Original pixels and audio are preserved as-is, and output dimensions may be cropped to a multiple of 16.

Pricing and availability

The video closes with the terms. This SDR-to-HDR feature is available right now inside Runway for anyone on the Max plan or higher. Runway's plans run Free, Standard, Pro, Max, and Enterprise in that order, so in practice this is limited to the Max and Enterprise tiers.

Editor's take

Line up Runway's recent announcements side by side and a clear direction emerges. As we saw at the AIF 2026 Seoul screening, AI video has already moved into the editing stage — figuring out what to keep and what to cut. Ruby fills in the next step: fitting a finished video to the actual delivery specs of a theater or a streaming platform. No matter how good the generation quality gets, a file that doesn't meet color space and bit-depth specs won't pass QC. Until now, that conversion has always had to happen outside the pipeline, as a separate step.

That's why the part of this announcement worth paying attention to isn't the list of output formats — it's the scope of what it accepts. Ruby isn't a tool built just for generated video; it takes SDR footage of any kind, including real camera shots. That signals Runway isn't positioning itself merely as a tool for polishing its own models' output, but as a post-production tool in its own right. Its competition has effectively shifted one lane over — away from other video generation services and toward color grading software.

Still, the 40-second input limit is a clear boundary at this stage. It's plenty for a single ad or a short clip, but not yet built for handing over an entire long-form video at once. Any production in Korea weighing whether to adopt AI video should first check the plan requirements alongside this length cap and the per-second credit billing structure. HDR delivery specs vary somewhat from broadcaster to broadcaster and platform to platform, so supporting both PQ and HLG doesn't automatically mean every delivery requirement is met. Worth watching over the coming weeks: how far Runway extends that length limit, and how quickly competing tools catch up with similar conversion capabilities.