Runway Gen-4.5
Runway's Gen-4.5 is a video generation model built on an Autoregressive-to-Diffusion architecture that held the top Artificial Analysis Elo position at launch with 1,247 points before Seedance 2.0 and Kling 3.0 surpassed it in early 2026.
7 min read
Runway launched Gen-4.5 on December 1, 2025, as its most capable video generation model to date. At launch it claimed the top position on the Artificial Analysis Text-to-Video leaderboard with an Elo score of 1,247, 21 points ahead of Google's Veo 3 in second place. That lead held for roughly three months before Seedance 2.0 and Kling 3.0 moved past it in early 2026.
TL;DR
- Best for: camera-controlled cinematic video with precise motion brush animation
- 12 credits/second via API ($0.12/s); subscription plans start at $12/month for 625 credits
- Held the Artificial Analysis #1 spot at launch (Elo 1,247) before Seedance 2.0 took the top position in early 2026
Overview
Gen-4.5 is Runway's fifth-generation video model and the first built on the Autoregressive-to-Diffusion (A2D) architecture, a technique Runway co-developed with NVIDIA. The model runs inference on NVIDIA Hopper and Blackwell GPU infrastructure and was trained end-to-end on the same hardware. The A2D design combines sequential language-style scene understanding from an autoregressive backbone with the visual quality of diffusion-based frame generation. That combination is what Runway credits for Gen-4.5's improvements in physics accuracy - objects carry realistic weight and momentum, fluids behave more naturally, and fine detail like hair strands and fabric weave holds across motion.
The model supports text-to-video, image-to-video, keyframe-based generation, and video-to-video modes. It does not include native audio generation. Any sound in Runway's promotional demos was added in post-production, and the company described audio integration as coming in a future update.
The December launch also came with a multi-year strategic partnership between Runway and Adobe. Gen-4.5 became available inside Adobe Firefly right away, making Runway the preferred API creativity partner for Firefly's video capabilities.
The Runway research page announcing Gen-4.5 at launch in December 2025.
Source: runwayml.com
Key Specifications
| Specification | Details |
|---|---|
| Provider | Runway |
| Model Family | Gen |
| Parameters | Not disclosed |
| Release Date | December 1, 2025 |
| Architecture | Autoregressive-to-Diffusion (A2D) |
| Input Types | Text, image, video (keyframe) |
| Output | Video (no native audio) |
| Resolution | HD |
| API Available | Yes (since February 10, 2026) |
| License | Proprietary |
| Open Source | No |
Benchmark Performance
At launch, Gen-4.5 sat at Elo 1,247 on the Artificial Analysis Video Arena, which uses blind human preference votes to rank models. That put it 21 points ahead of Google Veo 3 at 1,226, a gap Artificial Analysis translates to roughly a 53% win rate in direct comparisons.
By March 2026 the leaderboard had shifted. Seedance 2.0 moved to the top with Elo 1,268, followed by Kling 3.0 Pro at around 1,247. Gen-4.5 no longer occupies the top slot on the video generation benchmarks leaderboard, though it remains a competitive choice for specific use cases.
| Model | Artificial Analysis Elo (at Gen-4.5 launch) | Current Position |
|---|---|---|
| Runway Gen-4.5 | 1,247 (1st) | Outside top 3 |
| Google Veo 3 | 1,226 (2nd) | Outside top 3 |
| OpenAI Sora 2 Pro | 1,206 (7th) | Outside top 3 |
| Seedance 2.0 | Not yet released | 1st (~1,268) |
| Kling 3.0 Pro | Not yet released | 2nd (~1,247) |
The Elo scores above reflect the state of the leaderboard at Gen-4.5's December 2025 launch, with current positions reflecting the rankings after Seedance 2.0 and Kling 3.0 arrived in early 2026. For how Gen-4.5 stacks up on cinematic quality, see our Kling 3.0 review and Seedance 2.0 review for direct comparison outputs.
The model demonstrates strong improvements over Gen-4 in three areas: prompt adherence for complex multi-element scenes, physical realism in object movement, and frame-to-frame consistency in hair, fabric, and surface detail. Where it still falls short is in causal reasoning and object permanence across longer clips.
Key Capabilities
Gen-4.5's Motion Brush gives the most precise element-level animation control of any commercial video model at launch. Users paint regions on a source image, assign directional motion vectors to each region, and the model computes how those motions interact with scene geometry and each other. Version 3.0 of the Motion Brush, included at Gen-4.5's launch, adds independent camera control - pan, tilt, zoom, and depth-of-field adjustments - applied separately from subject motion. This is the feature that most distinguishes Gen-4.5 for filmmaking and compositing workflows.
Scene consistency tools support multi-shot production. Character identity, clothing, and environmental lighting carry over between separately produced clips, which reduces the manual continuity work that video AI historically required. The API's Camera Director feature enables precise camera choreography across an output without frame-by-frame keyframing.
Stylistic range is wide. The model produces photorealistic footage, non-photorealistic animation, and cinematic stylized work from the same architecture. Runway's promotional demos showed everything from VFX-heavy sequences to clean documentary-style footage, all produced from text or image prompts.
Adobe Firefly integrated Gen-4.5 at launch through a multi-year partnership with Runway.
Source: nofilmschool.com
Pricing and Availability
Gen-4.5 is available through Runway's subscription plans and, since February 10, 2026, through the Runway API. The subscription credit math matters here:
- Standard ($12/month billed annually): 625 credits - yields 52 seconds of Gen-4.5 output at 12 credits/second
- Pro ($28/month billed annually): 2,250 credits - yields about 3 minutes of output
- Max ($76/month billed annually): 9,500 credits - first access to new models, 1-month credit rollover
The Free plan (125 one-time credits) doesn't include Gen-4.5 access. Credits don't roll over on Standard or Pro tiers; they reset within 24 hours of the billing date.
Via the API, Gen-4.5 costs 12 credits per second, which at $0.01/credit equals $0.12 per second of video or $1.20 per 10-second clip. Compare that to Gen-4 Turbo at 5 credits/second for less demanding work, or Aleph 2.0 at 28 credits/second for video editing tasks.
Runway's API now also offers Seedance 2.0 (added May 28, 2026) at 36-150 credits/second depending on resolution, and Aleph 2.0 (added June 2, 2026) at 28 credits/second for in-context video editing. This makes the Runway API a multi-model platform rather than a single-model endpoint.
Gen-4.5 held the leaderboard for three months. That's a short reign in a fast-moving space, but the motion brush and camera control features still set it apart for production workflows.
Strengths and Weaknesses
Strengths
- Motion Brush 3.0 gives region-level animation control that competitors don't match at the same precision
- Camera Director enables precise camera choreography without frame-by-frame keyframing
- Scene consistency tools reduce continuity work across multi-shot workflows
- Adobe Firefly integration gives creative teams access without an API setup
- Mature API ecosystem with documented endpoints and predictable credit pricing
- Wide stylistic range from photorealistic to stylized animation in the same model
Weaknesses
- No native audio generation - sound must be added in post-production
- Causal reasoning failures documented: effects sometimes precede causes (smoke before fire, impact splash before contact)
- Object permanence issues in longer clips - objects can disappear unexpectedly, especially during extensions
- No longer holds the #1 Elo position; Seedance 2.0 and Kling 3.0 now score higher in blind preference tests
- Credit costs on Gen-4.5 are higher than Gen-4 Turbo (12 vs. 5 credits/second) for the same clip duration
- Consistency degrades when using the Extend feature to chain clips beyond a single generation
Related Coverage
- Video Generation Benchmarks Leaderboard - current rankings including Gen-4.5, Seedance 2.0, and Kling 3.0
- Kling 3.0 Review - direct comparison against Gen-4.5 for motion quality and 4K output
- Seedance 2.0 Review - the model that currently leads the leaderboard Gen-4.5 previously topped
- LTX-2.3 - open-source alternative for teams that need local video generation
- Best AI Video Generation Tools 2026 - full market comparison
FAQ
Is Runway Gen-4.5 the best AI video model?
As of June 2026, no. Seedance 2.0 and Kling 3.0 Pro score higher on the Artificial Analysis blind preference leaderboard. Gen-4.5 remains competitive for camera-controlled workflows and Adobe Firefly integration.
Does Runway Gen-4.5 generate audio?
No. Gen-4.5 has no native audio generation. Audio must be added in post-production. Runway has suggested audio support is planned for a future release.
How much does Gen-4.5 cost via the API?
The API charges 12 credits per second at $0.01 per credit, so $0.12/second or $1.20 per 10-second clip. Bulk credit purchases are available through the Runway developer portal.
When did Gen-4.5 release?
December 1, 2025. The API became available February 10, 2026.
What is the A2D architecture in Gen-4.5?
A2D stands for Autoregressive-to-Diffusion. It combines an autoregressive language model backbone for scene and prompt understanding with a diffusion decoder for visual generation. Runway co-developed the technique with NVIDIA and trained Gen-4.5 on NVIDIA Hopper and Blackwell GPUs.
Can I use Gen-4.5 in Adobe products?
Yes. As part of a multi-year partnership announced at launch, Gen-4.5 is available inside Adobe Firefly. Adobe users with a Firefly Pro plan can produce videos through the Runway Gen-4.5 backend.
Sources:
✓ Last verified June 24, 2026
