MKV to BMP Converter

Extract a BMP Frame from MKV Online

Pull a single still out of a Matroska (.mkv) video and save it as a Windows Bitmap (.bmp) — or grab a whole series of stills in one pass. This is frame extraction, not video conversion: you pick a moment on the timeline and get an image back. BMP is the format to choose when a legacy Windows application, an imaging SDK or a machine-vision tool refuses anything else; for everyday screenshots, PNG is smaller and just as exact.

How to Convert MKV to BMP

1. Upload Your MKV File: Drag the .mkv onto the page or click "+ Add Files" to select it. Several files can be queued and processed with the same settings.
2. Pick the Frame: Open Advanced Options. Frame Selection starts on Specific Frame with Time (seconds) at 0 — type the moment you want, such as 8.5 or 2.100 for two seconds and one hundred milliseconds. Switch to Multiple Screenshots to sample the whole timeline instead.
3. Set the Quality Preset and Resolution: The Quality preset list shows High and offers Medium and Low below it — these change the colour depth of the bitmap, not the sharpness of the capture. Image resolution starts on Keep original.
4. Convert and Download: Click Convert and download the .bmp. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically a few hours later — no sign-up, no watermark.

What Each Quality Preset Actually Writes

BMP has no quality dial in the JPEG sense — it is a raw pixel container, so the only thing a "quality" setting can change is how many colours each pixel is allowed. That makes this dropdown unusually consequential, and it is worth knowing exactly what each entry produces:

Note the ceiling: even the High preset is a 16-bit bitmap, not a 24-bit truecolour one. Microsoft's own documentation for the bitmap header states that "for 16-bpp bitmaps, if biCompression equals BI_RGB, the format is always RGB 555" — five bits each for red, green and blue. That is plenty for most stills, but on smooth gradients it can show faint banding that a 24-bit PNG would not. If you need every one of the source frame's colours, extract the frame as PNG instead.

Choosing Which Frame You Get

• Leave Time (seconds) at 0 and you get the very first frame of the video. On many files that is a black or near-black fade-in, which is the usual explanation for an "empty" looking export — set a timestamp a few seconds in.
• Type a decimal timestamp to land on a precise moment. 12.5 is twelve and a half seconds; 2.100 is two seconds and one hundred milliseconds.
• Switch to Multiple Screenshots to sample the whole file at a Capture Rate — anything from one frame every 0.1 seconds through to one frame every 10 seconds, with one frame per second as the starting point. Each capture comes back as its own separate image.
• Remember the source is the limit. The extracted frame carries whatever compression artefacts, motion blur and softness the video already had. Choosing a still moment rather than a fast pan makes a far bigger difference than any setting on this page.

BMP vs PNG vs JPG for an Extracted Frame

For a screenshot you intend to share or edit, MKV to PNG is the better default; for the smallest possible file, MKV to JPG. Reach for BMP when something specifically refuses everything else.

Frequently Asked Questions

What colour depth is the exported BMP?

At the High preset, 16 bits per pixel in RGB 555 — five bits each for red, green and blue, giving 32,768 possible colours. We confirmed this on encoder output: the file's header declares 16 bits per pixel with BI_RGB compression, which Microsoft documents as always meaning RGB 555. Medium and Low drop further, to a dithered 256-colour and 86-colour palette respectively. There is no 24-bit truecolour option on this page, so if your workflow specifically needs a 24-bit bitmap, convert the frame to PNG here and re-save it as 24-bit BMP in an image editor.

Why is one BMP frame so much bigger than the entire MKV?

Because they compress in completely different ways. The MKV holds video compressed with a codec like H.264 or VP9 that stores mostly the differences between frames. A BMP at the High preset stores every pixel of one frame as raw bytes with no compression at all: 1920 × 1080 pixels × 2 bytes each is about 4.1 MB before the header. That is normal for an uncompressed bitmap and not a sign that anything went wrong. Medium and Low apply RLE compression and a reduced palette, which is why they are dramatically smaller.

Which frame do I get if I leave the time at zero?

The first frame of the video. Frame Selection starts on Specific Frame with Time (seconds) set to 0, so converting without touching it captures the opening instant — which on films, exports from editors and screen recordings is very often black. If your BMP looks empty, that is almost always the cause. Enter a timestamp several seconds into the clip and convert again.

Can I pull several stills out of one MKV at once?

Yes. Switch Frame Selection to Multiple Screenshots and choose a Capture Rate. The options run from one frame every 0.1 seconds (equivalent to sampling at 10 fps) down to one frame every 10 seconds, starting at one frame per second. Every captured moment becomes its own separate .bmp. These are independent stills — nothing reassembles them into an animation. If a moving image is what you actually want, use MKV to GIF or MKV to APNG instead.

Does saving the frame as BMP make it look better than the video?

No. BMP stores pixels without lossy compression, but it cannot recover detail the video codec already discarded. The frame you extract is capped by the frame that existed in the file: if the source is a heavily compressed stream, you will see exactly the same blocking and softness in the bitmap, just stored more expensively. Extraction preserves; it never restores. Picking a static moment rather than one mid-motion is the only real way to get a sharper still.

Why do the Medium and Low presets look speckled?

Because both reduce the image to a small palette and use Floyd–Steinberg dithering to fake the missing colours. Dithering scatters pixels of the available colours in patterns that read as an intermediate shade from a distance — the speckle is that pattern seen up close. It is the standard trade for palettised formats. If you see banding or speckle you cannot live with, stay on High, or extract as PNG for full truecolour.

Should I use BMP or PNG for a screenshot I want to share?

PNG, in almost every case. PNG is lossless, keeps full 24-bit colour rather than RGB 555, compresses to a fraction of the size, and opens everywhere including in browsers and messaging apps. Windows, macOS and Linux all save screenshots as PNG by default for those reasons. BMP earns its place only when a specific application, SDK or piece of industrial software refuses to read anything but an uncompressed Windows bitmap — that requirement is the entire reason this page exists.

Can the BMP hold transparency?

Not from this conversion. Video frames from an MKV are opaque to begin with — codecs like H.264 and HEVC have no alpha channel — and the bitmaps written here are 16-bit RGB or palettised, neither of which carries alpha. If you need a still with genuine transparency you would have to cut it out yourself in an editor after extraction, working from a PNG so you have a format that can store the alpha channel.

What happens to my video after the conversion?

Your MKV is uploaded over an encrypted connection, the requested frames are rendered on our servers, and both the upload and the resulting bitmaps are deleted automatically a few hours later. Nothing is shared or made public and there is no sign-up or watermark. Your original .mkv is never modified — every still is written as a new file for you to download.