AI Video Upscaling to 4K from HD in 2026
Step-by-step process to convert 1080p source into 4K masters using the video upscalers inside Flixly. Includes model comparison table and verification checks.
TL;DR
Load 1080p footage into the Video to Video tool, choose an upscaler such as Topaz Astra Creative Upscale, set 4K output, run a sharpen pass in AI Video Effects, then export ProRes 4444. The workflow turns a 42-second clip into a 4K master, with each pass quoted before it runs.
A 42-second 1080p product demo arrives at 4:15 pm for a 4K trade-show screen that opens at 9 am.
Check the source specs first
Open the file in any player and note the numbers: 1920 by 1080, 24 fps, 42 seconds, H.264. These values set the upscale targets and credit estimate.
Pick the model that matches the motion
Use a dedicated upscaler, not a generation model: Seedance 2.0, Kling 3.0, Veo 3.1 and Wan 2.7 create new clips from text or images and cannot take a video in. Topaz Starlight Upscale rebuilds detail that isn't in the source, up to 4K. Topaz Astra Creative Upscale reimagines fine detail, typically at 4K, and takes clips up to 5 minutes. FLUX Video Upscale reaches 4K with a source-faithful Precise mode or a Creative mode, on clips up to 20 seconds. Kandinsky 6.0 VSR upscales 2x, 2.25x or 4x with stable, flicker-free frames. Sora 2 was retired on 2026-09-24.
| Model | Max output | Upscale factor | Credits per 10 s | Best for |
|---|---|---|---|---|
| Topaz Starlight Upscale | 4K | not listed | quoted in-app | Rebuilding missing detail |
| Topaz Astra Creative Upscale | 4K (typical) | not listed | quoted in-app | Longer clips, up to 5 minutes |
| FLUX Video Upscale | 4K | not listed | quoted in-app | Clips up to 20 s, Precise or Creative mode |
| Kandinsky 6.0 VSR | not listed | 2x, 2.25x or 4x | quoted in-app | Stable, flicker-free frames |
Load the clip into Video to Video
Go to the Video to Video page. Drop the 1080p file, select Topaz Astra Creative Upscale (FLUX Video Upscale caps clips at 20 seconds, too short for this 42-second file), and set the target resolution to 4K. Submit. The job returns a 4K file at the cost quoted when you submit.
Refine edges with AI Video Effects
Open the new 4K file on the AI Video Effects page. Apply the sharpen filter at strength 0.6 and the noise reduction pass at 0.4. Export a 10-second test segment at 4K. Play it back at 200 percent zoom to confirm edge halos stay below visible levels.
Extend length if the client requests
If the final cut needs 60 seconds instead of 42, jump to the Image to Video tool. Generate the extra 18 seconds from the last frame with Seedance 2.0 (4–15 seconds per clip, up to 4K, so two clips). Stitch the new tail in any editor and check that it matches the master's color and grain.
Create a motion poster for social cut-downs
Use the same 4K master on the Motion Poster page. Set duration to 6 seconds, loop the first frame, and export a 1080p square version for Instagram. This step reuses the high-resolution source so the downscaled post stays crisp.
Verify before delivery
Check three frames at 0 s, 21 s, and 41 s under 4K playback. Confirm no ringing around logos and that text remains legible at 400 percent zoom. If any frame shows softness, rerun only that segment through Video to Video with a 0.3 sharpen boost.
Export final deliverables
Render the full 4K master as ProRes 4444 at 24 fps. Create a 1080p proxy at the same time for quick client review. Both files land in the project folder with the original 1080p source for version control.
Repeat the workflow on the next project
Open the Video to Video page again, load the new 1080p clip, and apply the same settings. The saved preset keeps resolution and model fields populated for the second job.
