FrameScale AIHow to upscale video to 4K for free with AI
Normal scaling only makes pixels bigger. AI upscaling rebuilds detail the source never stored, so edges, text and textures look sharp at 4K. Here is how to do it for free with FrameScale AI, without uploading your video anywhere.
What AI upscaling actually does
When a player or editor enlarges 1080p to 4K, it interpolates between existing pixels (bicubic or Lanczos). The result is bigger but soft. An AI super-resolution model such as Real-ESRGAN was trained on millions of image pairs, so it predicts plausible high-resolution detail: crisp edges, readable text, clean textures and less blocky compression.
BeforeAfter · FrameScale
Which scale to use
| Source | Scale | Result |
|---|---|---|
| 1920×1080 (Full HD) | 2× | 3840×2160 (4K UHD) |
| 1280×720 (HD) | 2× | 2560×1440 (QHD) |
| 960×540 | 4× | 3840×2160 (4K UHD) |
| 720×576 / 720×480 (DVD, SD) | 4× | about 2880 pixels wide, beyond Full HD |
Step by step
- Install FrameScale AI. Download the installer for Windows, macOS or Linux from the download section and install it. It is free, needs no account, and runs entirely on your computer.
- Add your video. Open FrameScale AI and drag your clip onto Drop videos here. It reads anything FFmpeg can decode: MP4, MKV, MOV, AVI, MPEG-2, ProRes and more.
- Turn on Upscale and pick a model. In the pipeline on the right, switch on Upscale. For camera footage choose Real-ESRGAN x4+ (live action) for the best detail, or Real-ESRGAN General v3 (live action, fast) for speed, with a Noise removal slider. For anime and cartoons choose Real-ESRGAN x4+ Anime or Real-ESR AnimeVideo v3 (fast).
- Choose 2× or 4×. Use 2× for 1080p to 4K and 4× for low-resolution sources (see the table above).
- Preview 2 seconds. Drag the marker under the viewer to a busy scene and click Render 2 s. A progress bar shows the time left; then compare the result split or side by side, and zoom in to check fine detail.
- Pick the output format. Under output, choose HEVC 10-bit (best compatibility for 4K) or AV1 10-bit (smallest files) in MP4 or MKV, and a quality level. HDR, audio, subtitles and chapters are carried over automatically.
- Render. Click Render. The job is written in 4-second segments, so you can pause, quit or even survive a crash and continue where it stopped.
Tips for the best 4K result
- Clean before you enlarge. Noise and compression blocks get upscaled too. Turn on Denoise (NAFNet for camera footage) before Upscale for grainy or heavily compressed sources.
- Faces look soft? Add Face Fix. It finds faces and restores them with CodeFormer; the Fidelity slider keeps them closer to the original.
- Speed. On a modern GPU, Real-ESRGAN General v3 turns 540p into 4K at around 13 frames per second; the heavier x4+ model is slower but more detailed. Eco mode caps GPU load for long, quiet renders.
- Keep the original. FrameScale never overwrites your source or an existing file.
Old tapes? Interlaced VHS and DV need deinterlacing first. See how to restore VHS tapes with AI.
Frequently asked questions
Can I upscale video to 4K for free?
Yes. FrameScale AI is free and open source, with no watermark, no resolution limit and no account. It uses your own GPU, so nothing is uploaded.
Does AI upscaling really add detail?
It reconstructs plausible detail learned from training data, which looks far sharper than normal scaling. It cannot recover information that was never captured, so very blurry sources improve less.
How long does upscaling take?
It depends on the model, resolution and GPU. On a current mid-to-high-end GPU, the fast General v3 model upscales 540p to 4K at roughly 13 frames per second; a 10-minute 1080p video to 4K takes from minutes to a few hours.
What GPU do I need?
Any Vulkan-capable NVIDIA, AMD or Intel GPU, or a Mac with Apple Silicon. 4 GB of video memory is comfortable; it also runs on the CPU, much more slowly.
Try it on your own footage
FrameScale AI is free and open source for Windows, macOS and Linux. No account, no watermark, no upload.