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RunwayML
Gen-4.5
RunwayML's video generation model supporting both text-to-video and image-to-video with customizable duration, aspect ratio, and content moderation controls.
Updated September 3, 2026
Credits
78 / clip
Turnaround
~90s / 5s clip
Max clip
20s
Resolution
1080P
Gen-4.5 sample output
1080P · 5-20s
RunwayML
Gen-4.5
When to pick Gen-4.5
At 78 credits per generation, Gen-4.5 sits in the middle of the catalog price ladder — 18 models are cheaper, 3 are pricier. ~90s / 5s clip is not draft-loop speed; treat Gen-4.5 as the finisher for clips that ship. Clips run 5-20s, up to 20 seconds. Output is silent by design — plan on adding audio in your editor, which is often the cheaper path when you are scoring properly anyway. Where it earns its slot: text & image to video, customizable, moderation controls, per our catalog tagging. Reach for Gen-4.5 when text & image to video matters most and you would rather not manage a separate RunwayML subscription to get it.
When to look elsewhere
If budget is the dominant constraint, FLUX 3 Video produces solid clips at 75 credits — 3 credits cheaper per generation than Gen-4.5. Seedance 2.0 Mini turns a clip around in ~20s / 5s clip where Gen-4.5 takes ~90s / 5s clip; that gap compounds badly across twenty drafts. Gen-4.5 caps at 20 seconds; Aleph 2 goes to 30 when the shot cannot be cut. Gen-4.5 produces silent video — if the clip needs to ship with sound, LTX-2.5 Fast generates synchronized audio for 18 credits or less.
Gen-4.5 specifications
- Vendor
- RunwayML
- Credits
- 78 credits / clip
- Turnaround
- ~90s / 5s clip
- Max resolution
- 1080P
- Clip length
- 5-20s (max 20s)
- Native audio
- No
- Inputs
- text, image
- Data policy
- Third-party
Gen-4.5 FAQ
How much does Gen-4.5 cost?
Gen-4.5 costs 78 credits per generation on FlowAIVideo. 18 models in the catalog are cheaper and 3 are pricier. One credit balance covers every model, so you can spend it on Gen-4.5 today and a different model tomorrow without a second subscription.
How long does Gen-4.5 take to generate a clip?
Typical turnaround is ~90s / 5s clip. 17 models in the catalog are faster. Latency scales with clip length, so a maximum-length render takes longer than a short one.
What resolution and clip length does Gen-4.5 support?
Gen-4.5 outputs up to 1080P, with 720P, 1080P available. Clips run 5-20s, with a maximum single-clip length of 20 seconds. The longest single generation in the catalog is 30 seconds on Aleph 2.
Does Gen-4.5 generate audio?
No — Gen-4.5 produces silent video. If you need generated sound, LTX-2.5 Fast, Seedance 2.5, FLUX 3 Video all produce synchronized audio natively. Otherwise add your own audio in the editor, which is usually the better route when you are scoring the piece properly.
What inputs does Gen-4.5 accept?
Gen-4.5 accepts text, image inputs. Its supported capabilities are t2v, i2v, configurable-duration, content-moderation. Supplying a reference image is the strongest way to pin composition and identity.
Can I compare Gen-4.5 with other models?
Yes — send one prompt to Gen-4.5 and any other model in the catalog at the same time and compare the clips side by side. Fix the prompt and duration and judge prompt adherence before aesthetics; a clip that looks good but shows the wrong thing is a failure.