X3F to MKV Converter

How to Convert X3F to MKV Online

1. Upload Your X3F Files: Drag and drop the Sigma RAW files from your SD, DP, or sd Quattro shoot, or click "+ Add Files" to select them. Multiple files queue together for a single slideshow.
2. Pick Merge Strategy and Quality Preset: Choose "Merge images" to assemble all X3F frames into one MKV slideshow, or "Video per image" to render a separate clip per RAW file. Quality Preset defaults to Very High (Recommended); switch to Constant Quality for predictable per-frame compression or Constraint Quality to cap bitrate without overshooting.
3. Set Image Duration, Resolution, and Background (Optional): Image Duration controls how long each Foveon frame holds on screen (default 5 seconds per frame). Toggle Video Resolution between Keep Original and Fixed Resolutions (1280x720, 1920x1080, 2560x1440, 3840x2160) — width and height fields keep aspect ratio automatically. Background Color defaults to Black for letterboxing when the X3F aspect ratio differs from the chosen frame size.
4. Convert and Download: Click Convert. X3F demosaicing and MKV muxing run on our servers — no Sigma Photo Pro install, no watermark, no sign-up.

Why Convert X3F to MKV?

X3F is the proprietary RAW container Sigma cameras with Foveon X3 sensors write to disk, encoding red, green, and blue at every photosite via three stacked photodiodes rather than the Bayer mosaic interpolation used by Canon, Nikon, and Sony. The format debuted with the Sigma SD9 in 2002 and continued through the SD10 (2003), SD14 (2006), SD15 (2010), SD1 Merrill (2011), DP1/DP2/DP3 Merrill (2012), and the dp Quattro and sd Quattro lines (2014-2016). Sigma's RAW data is encrypted, so few editors open X3F natively — converting to a video container makes Foveon shoots viewable on any device that plays MKV. Matroska, launched on December 6, 2002 by the non-profit Matroska.org, is a codec-agnostic container that holds an unlimited number of video, audio, picture, and subtitle tracks in one file under LGPL and BSD licenses.

• Foveon review reels for clients — Send a self-contained MKV slideshow to a client who doesn't run Sigma Photo Pro, X3Fuse, or a Foveon-aware RAW developer. The MKV plays in VLC, MPV, Plex, Jellyfin, and Kodi without plug-ins.
• Archive sd Quattro and dp Quattro shoots — Bundle hundreds of X3F frames into one Matroska file with chapter markers per image so you can scrub a season's work without scanning a folder of obscure RAW files.
• Time-lapse from interval-shot X3F bursts — Sigma's SD1 and sd Quattro H shoot bracketed series at up to 5 fps; an MKV with H.264 inside renders the sequence as smooth motion at any frame rate you pick.
• Loadable in NLE projects — DaVinci Resolve, Premiere Pro, and Final Cut Pro all import MKV via FFmpeg-based decoders, letting you treat the slideshow as a single track instead of an image sequence.
• Color science showcase — Foveon's per-pixel RGB capture produces distinctive skin tones and foliage rendering; MKV preserves the developed look losslessly with FFV1 or near-losslessly with H.265 at CRF 18.
• Background score and subtitle tracks — Because Matroska supports multiple audio and subtitle streams in one file, you can later mux a music bed, voiceover, and on-screen captions without re-encoding the video.

X3F vs MKV — Format Comparison

Quality Preset Quick Guide

Matroska Codec Quick Guide

For finer control over the conversion you can also output X3F to MP4, X3F to WebM, or X3F to MOV. If you only need stills, convert X3F to JPG, X3F to PNG, or X3F to TIFF instead.

Frequently Asked Questions

Why convert an X3F still to MKV at all — isn't MKV a video format?

MKV is a container, not a still format, so the converter builds a slideshow: each X3F image becomes one or more frames in the output video. With one X3F you get a single-image clip whose length equals the Image Duration setting; with many X3F frames you get a true slideshow. This is useful when you need a self-playing review reel a client can open in VLC without installing Sigma Photo Pro.

Will the Foveon color rendering survive the conversion?

The browser converter demosaics the X3F into RGB frames first, then encodes those frames into the chosen codec. Foveon's per-pixel RGB advantage shows up most in the RAW-to-RGB step, so picking Very High or Constant Quality keeps that detail intact. Lossless FFV1 inside MKV preserves it bit-perfect at the cost of large files; H.264 at the default preset is what most users want.

How long will each X3F image appear in the MKV?

Image Duration controls per-frame hold time and defaults to 5 seconds. The dropdown ranges from very short (1/60 second, for true time-lapse) up to 10 seconds for slow review reels. If you set 5 seconds and queue 24 X3F files, the resulting MKV runs exactly 2 minutes.

Why is there a Background Color setting?

Sigma sensors shoot in several aspect ratios depending on the camera (the dp Quattro is 3:2, the sd Quattro H also 3:2, the SD9 was 3:2 at 2268x1512). When you choose a Fixed Resolution like 1920x1080 (16:9), the X3F frame won't fill the canvas — Background Color fills the letterbox bars. Black is the default; pick a brand color for a polished presentation reel.

Which Sigma cameras produce X3F files I can convert?

Every Sigma body with a Foveon X3 sensor: the SD9 (2002), SD10 (2003), SD14 (2006), SD15 (2010), SD1 and SD1 Merrill (2011), DP1/DP1s/DP1x (2008), DP2 (2009), DP1/DP2/DP3 Merrill (2012), and the dp0/dp1/dp2/dp3 Quattro and sd Quattro / sd Quattro H bodies (2014-2016). Sigma discontinued the DP Quattro line in 2022 and no new Foveon camera has shipped as of 2025.

Can I add a music track or subtitles to the MKV?

Not in a single browser pass — this tool muxes only the video stream from the X3F slideshow. Matroska's design supports unlimited audio and subtitle tracks, so after downloading the MKV you can add a music bed or SRT captions with MKVToolNix or FFmpeg without re-encoding the video.

Will the MKV play in QuickTime or on iOS?

QuickTime and Apple's stock iOS players don't decode MKV natively. Use VLC for iOS, Infuse, or MPV on macOS; or convert the file with MKV to MP4 for first-class Apple playback. Android, Windows Media Player (Windows 10+), Plex, Jellyfin, and Kodi all play MKV out of the box.

Does the converter open every X3F variant, including the encrypted Quattro files?

The RAW pixel data in X3F is wrapped in Sigma's proprietary encryption, which is why so few editors open the format. Server-side decoding handles the published Foveon variants from the SD9 through the dp Quattro and sd Quattro lines. Files from cameras released after the Foveon line was discontinued in 2022 are unlikely in practice, but if a specific X3F won't decode the converter will report it rather than produce a corrupted MKV.

Are my X3F files uploaded to a server?

Files process on our servers for this conversion — they're not retained on our servers and there is no sign-up or watermark. RAW shoots from client jobs stay on your machine.