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Supports: MKV
This converter pulls a single frame (or a series of frames) out of an MKV video and saves it as a HEIC still — not a video file, but a high-efficiency photo. If the screenshot is headed for an Apple device or you care about the smallest possible file at full quality, extract to HEIC; if you need the frame to open anywhere without fuss, grab a JPG instead.
| Property | HEIC (this page) | JPG (extract as JPG) |
|---|---|---|
| Underlying standard | HEIF — ISO/IEC 23008-12 | JFIF / ISO/IEC 10918 |
| Image codec | HEVC (H.265) | Baseline JPEG (DCT) |
| Color depth | Up to 10-bit (12-bit in the spec) | 8-bit only |
| File size at equal quality | Roughly half the size of JPG | Baseline |
| Native browser display | Safari 17+ only | Every browser since the 1990s |
| Default platform | Apple iOS 11+ / macOS High Sierra+ | Universal |
| Best for | Apple workflows, storage-tight archives | Sharing, web, editing anywhere |
Because they are unrelated formats. MKV is a video container holding an entire timeline of frames plus audio and subtitles; HEIC is a single-image (or image-sequence) photo format. Renaming changes the extension but not the bytes inside, so the file stays broken. The frame has to be decoded out of the video and re-encoded as HEIF, which is exactly what this converter does.
It can look identical or sharper. A still pulled from the timeline is a clean copy of that exact frame, and HEIC's HEVC compression preserves more detail at a given file size than JPG. The one caveat is motion: if you land on a frame during fast camera movement, that frame may be motion-blurred in the source itself — step the "Time (seconds)" value a fraction of a second to find a still moment.
Yes. At matched visual quality, HEIC files are typically around half the size of JPG because HEVC is far more efficient than the decades-old DCT compression JPG uses. In our testing, a single 1080p frame grabbed from an MKV came out around 180 KB as HEIC versus roughly 350 KB as a high-quality JPG of the same frame.
Not by default everywhere. Native HEIC display in browsers is currently Safari 17+ only; Chrome, Firefox, and Edge do not render it. Windows can open HEIC after installing the HEVC/HEIF extensions from the Microsoft Store, and recent Android builds support it. If the recipient's setup is unknown, extract the frame as JPG instead — or convert the HEIC you made back with HEIC to JPG.
Yes. Pick "Multiple Screenshots" and choose a capture interval (for example, one frame per second or one every five seconds). The converter walks the timeline at that spacing and returns every still as individual HEIC files bundled in a ZIP, which is handy for building a contact sheet or pulling thumbnails from a long clip.
It can. HEIF supports 8-, 10-, and 12-bit color depths per ISO/IEC 23008-12, so a 10-bit HDR frame retains its wider tonal range where an 8-bit JPG would band the gradients. Keep in mind some editors — Adobe Photoshop among them — only read 8-bit HEIC, so a 10-bit file may be down-converted when you open it there.
Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours later. There is no sign-up, no watermark, and files are never shared or made public.