Check the source dimensions
Open a compatible video in the 4K extractor and read the resolution shown above the preview. A 3840 × 2160 frame contains about 8.3 million pixels. Exporting a lower-resolution source cannot create genuine 4K detail.
Use PNG for an editing master
The canvas is sized to the decoded video picture, so the export is not limited to the small preview on the page. PNG avoids an additional lossy image encode. JPG and WebP can reduce file size but use lossy settings in this tool. All formats may still show artifacts already present in the video.
Capture a small batch first
Each uncompressed working 4K canvas is roughly 32 MB before image encoding, and the browser also retains decoder resources and captured blobs. Try a short range instead of sampling an entire long recording. The gallery stops at 120 images or 96 MB of encoded images, whichever is reached first.
Watch for codec and color limits
A file’s resolution does not establish playback compatibility. HEVC support varies, and a browser may not play professional codecs inside MOV. Use a compatible export if necessary. This tool does not claim color-managed HDR or Rec.2020 preservation; use a verified color-managed workflow when color fidelity is critical.
Verify the downloaded result
Inspect the file dimensions and important details in an image viewer. Compare at 100% size with the source rather than judging only the browser preview. A native-size still can still contain motion blur, missed focus, or compression softness.
The supported pixel limit is 8.3 million per frame. Higher-resolution sources should be converted or handled with another tool before opening them here.
Calculate the cost of a 4K still
A UHD picture at 3840 × 2160 contains 8,294,400 pixels. One raw four-channel pixel buffer is about 31.6 MiB before additional canvas storage and image encoding. The compressed PNG or JPG can be much smaller, but its file size does not describe the complete capture memory requirement.
Start with one candidate, download it, and inspect its width and height in another application. This release admits decoded frames up to 8,294,400 pixels, including 3840 × 2160; it does not claim 8K support. A file marked “4K” may use a different frame shape, so inspect the reported dimensions rather than assuming every 4K camera format fits the limit.
For a high-resolution batch, choose a short range and a sensible interval. Detailed PNG pictures may reach the 96 MB retained-image limit before the 120-frame cap. Download and clear between batches. If a phone struggles to seek or encode the source, make a compatible working copy or use a desktop editor. Preserve the original when colour fidelity, HDR processing, or frame-accurate extraction matters.
Open a compatible local file and capture a few moments for comparison.
Open frame extractor