Define whether you are generating or modifying
If you start with a written shot or a still image, compare generation controls and accepted results. If you start with recorded footage and need to preserve timing, compare footage modification. Those tasks have different inputs and different acceptance criteria.
Do not use the maximum editable footage length as a generation-duration claim. Our Luma profile leaves the unconfirmed single-pass generation limit open. This avoids making the two products look directly comparable on a field that the cited evidence does not establish.
Published differences that matter
| Field | Runway Gen-4.5 source | Luma Ray3.2 source |
|---|---|---|
| Starting point | Text or text with an image | Text, image and footage workflows described |
| Output information | 720p base; 24 or 25 fps | 1080p, HDR and EXR described |
| Direction | Prompt-led shot creation | Up to 16 keyframes described |
| Billing | 12 web credits per generated second | Credits vary with task and output |
| Important caveat | Web credits are not an API dollar price | 20-second Modify limit is not a text-to-video limit |
These are source-backed distinctions, not measured differences in visual quality or speed. Your account and selected workflow may expose additional conditions.
Use two separate pilot tasks
For generation, use a short tabletop shot and match the required camera move and frame shape. For modification, use footage you own and define exactly what must stay unchanged. A tool that does not support a task should be marked as outside that comparison, rather than given an invented score.
Review identity, contact, geometry and the ending state. If the shot is intended for a compositor, send one result through the actual receiving pipeline. Color and file-format problems can matter more than a visually attractive preview.
Compare usable output and manual work
Record actual charges from the selected workflow and include rejected attempts. Keep software plan cost separate from usage charges unless you explicitly allocate that plan cost across the production. Note any export processing you add.
Track edit time as a separate line. If a generated file needs hours of repair to meet the brief, that is material to the decision. Our calculator helps model acceptance rate; it does not retrieve subscription pricing or account entitlements.
A practical selection rule
Shortlist Gen-4.5 for a pilot when your task is a short new shot from text or an image. Include Ray3.2 when modifying recorded motion, keyframe direction or a grading/compositing handoff is central. These are editorial workflow recommendations based on documented controls.
Make the final decision with a representative shot, the actual account settings and a saved acceptance record. We have not run a controlled comparison and do not assign a numerical winner.
Sources and verification
Reviewed October 25, 2026. Provider documentation supports specifications; it is not evidence of an independent performance test.