Turn Real Footage Into Directed Shots with Runway Gen-4 Aleph
Gen-4 Aleph refers to Runway’s Gen-4 Aleph video-to-video model (API model: gen4_aleph ), developed by Runway. Runway launched Aleph to paid plans on July 31, 2025 and later added Aleph to the Runway API on August 1, 2025 . It’s built for in-context video transformation: you bring the video, you describe the change, and Aleph generates a coherent edited result while leveraging the original scene as context.
Unlike “start-from-scratch” generators, Gen-4 Aleph is designed for creators who already have footage—product shots, live action plates, social clips, or rough previs—and need fast, targeted changes. Official Runway workflows and examples highlight edits such as adding VFX, changing seasons/weather, relighting, replacing or removing objects, generating new camera angles, and predicting the next shot in a sequence .
On Vidofy.ai, you can treat Gen-4 Aleph like a post-production tool: upload your clip, write a precise instruction (what changes, what must stay), optionally guide the result with a reference image, and iterate quickly—without dealing with separate model endpoints, file handling, or prompt bookkeeping across tools.
Edit-First vs Generate-First: Gen-4 Aleph vs Kling 2.1
Both Gen-4 Aleph and Kling 2.1 target modern AI video creation—but they shine in different workflows. Gen-4 Aleph is optimized for transforming existing footage, while Kling 2.1 is positioned as a video generation model series with multiple quality modes. Here’s the most evidence-based breakdown we can provide from official sources (latest check).
| Feature/Spec | Gen-4 Aleph | Kling 2.1 |
|---|---|---|
| Developer / Provider | Runway | Kuaishou (Kling AI) |
| Primary workflow | Video-to-video generation (transform a provided video via prompt) | Video generation model series (Standard / High Quality / Master Edition mentioned) |
| Officially stated output resolution / modes | Accepted API output ratios include: "1280:720", "720:1280", "1104:832", "960:960", "832:1104", "1584:672", "848:480", "640:480" | Standard mode: 720p; High Quality mode: 1080p; plus 2.1 Master Edition (resolution not explicitly re-stated in the same release) |
| Prompt input limit (official) | Required promptText: 1–1000 characters | Not verified in official sources (latest check) |
| Reference image support (official) | Supports references; currently up to one reference is supported | Not verified in official sources (latest check) |
| Pricing / credits (official source) | Runway API: 15 credits per second | 2.1 predecessor pricing referenced by Kuaishou: 35 credits per five-second 1080p video |
| Accessibility | Instant on Vidofy | Kling 2.1 Also availabe on Vidofy |
Detailed Analysis
Analysis: Why Gen-4 Aleph wins for post-production edits
Runwa Gen-4 Aleph is built around a simple, production-friendly assumption: you already have a clip, and you need a controlled transformation. Runway’s Aleph prompting examples emphasize edit verbs (add/remove/replace/relight/restyle) and workflows like VFX insertion, weather changes, object removal, and even new camera angles—use cases that map directly to post-production needs rather than “first frame only” ideation .
On Vidofy, that translates into a faster loop for creators and teams: upload footage → write a precise change request → regenerate variations until the shot matches your cut—without re-building scenes from scratch.
Analysis: Where Kling 2.1 can be the better choice
Kuaishou positions Kling 2.1 as a cost-effective, efficient content generation series with distinct modes (Standard at 720p and High Quality at 1080p) and a premium 2.1 Master Edition for stronger motion and semantic responsiveness .
If your workflow is “generate lots of short-form variations quickly” rather than “surgically edit this exact piece of footage,” Kling 2.1 can be a strong alternative—especially when you want mode-based quality selection rather than edit-first control.
Verdict: Choose the Model That Matches Your Footage Reality
How It Works
Follow these 3 simple steps to get started with our platform.
Step 1: Upload your source clip
Drop in the video you want to transform. Gen-4 Aleph is a video-to-video workflow, so your input footage is the starting point for every edit.
Step 2: Write an edit prompt (optionally add a reference image)
Use clear action verbs (remove/replace/relight/restyle) and specify what must stay unchanged. If you need to steer style or lighting, add a reference image to guide the look.
Step 3: Generate, compare, and iterate in Vidofy
Run variations, review outputs side-by-side, and refine prompts until the shot matches your cut. When needed, switch to Kling 2.1 on the same platform for generation-first workflows.
Frequently Asked Questions
What is Rnway Gen-4 Aleph, exactly?
Gen-4 Aleph is Runway’s Gen-4 Aleph model, exposed in the Runway API as gen4_aleph and used for video-to-video generation—meaning it transforms a provided video based on your prompt .
Do I need to upload a video to use Gen-4 Aleph on Vidofy?
Yes. In the official Runway API, the Aleph workflow requires a videoUri input along with a required promptText . Vidofy mirrors this intent: you start from a clip, then describe the change.
Can Gen-4 Aleph use a reference image for style or lighting?
Yes. Runway’s Aleph prompt guide describes accompanying your input video with an image to influence color, styles, and lighting . In the Runway API, references are supported and currently up to one reference is supported .
What output sizes does Gen-4 Aleph support?
In the official Runway API, the Aleph video-to-video endpoint supports ratio values including: "1280:720", "720:1280", "1104:832", "960:960", "832:1104", "1584:672", "848:480", and "640:480" .
How is Gen-4 Aleph priced?
In the official Runway API pricing guide, gen4_aleph is priced at 15 credits per second , and API credits are listed at $0.01 per credit . Vidofy pricing and packaging may differ depending on your plan, but the underlying model cost structure is defined by the provider.
What’s officially confirmed about Kling 2.1 quality modes?
Kuaishou states that the Kling AI 2.1 model series includes a Standard (720p) mode and a High Quality (1080p) mode . Other technical limits (duration, fps, aspect ratios) are not verified in official sources for Kling 2.1 in this page’s latest check.