X3F to MJPEG Converter

How to Convert X3F to MJPEG Online

1. Upload Your X3F Files: Drag and drop one or more .X3F files from your Sigma SD or DP series camera, or click "+ Add Files". Batch upload is supported — every uploaded image becomes one frame (or one self-contained clip) in the output.
2. Pick Merge Strategy and Image Duration: Choose Merge images to splice every frame into a single MJPEG, or Video per image to render each X3F as its own short clip. Set Image Duration (default 5 seconds per frame; options range from 1/60 of a second up to 10 seconds) to control how long each Foveon still holds on screen.
3. Set Quality Preset, Background Color, and Resolution (Optional): Under File Compression pick the Quality Preset (Constant Quality default) and a Preset of Lowest through Highest — Very High is the recommended starting point for MJPEG, which is intra-frame only and benefits from a higher per-frame quality level. Choose a Background Color (Black default) for any letterbox padding, then keep original resolution or apply a fixed preset (720p, 1080p, 1440p, 2160p, 4320p) or custom Width × Height.
4. Convert and Download: Click Convert. The Foveon RAW data is decoded, resized if requested, then each frame is JPEG-compressed and packed into an .mjpeg stream you can drop straight into FFmpeg, VirtualDub, DaVinci Resolve, or any NLE that ingests Motion JPEG. processing runs on our servers — no sign-up, no watermark.

Why Convert X3F to MJPEG?

X3F is Sigma's proprietary RAW container for cameras built around the Foveon X3 sensor — a three-layer stack that captures full RGB at every pixel site instead of interpolating from a Bayer mosaic. Outside of Sigma Photo Pro, the official X3F Plug-in for Photoshop, and a handful of third-party decoders (dcraw, X3Fuse, Iridient Developer), almost nothing opens these files natively, which makes them a poor fit for video pipelines. Motion JPEG solves that by storing each frame as a standalone JPEG inside an AVI- or MOV-style stream — every frame is independently decodable, the format is intra-frame only, and Safari, Chrome, Firefox, Edge, QuickTime, VLC, and FFmpeg all decode it without a separate codec install.

• Foveon-to-NLE bridge — Premiere Pro, DaVinci Resolve, and Final Cut Pro do not ingest X3F. Converting an X3F bracket or burst into a single MJPEG clip lets you place Sigma SD1, SD Quattro, DP Merrill, or dp Quattro stills directly on a timeline without round-tripping through TIFF sequences.
• Frame-accurate scrubbing — because MJPEG has no inter-frame prediction, every frame is a keyframe. Editors can scrub backward and forward on a slow drive without the GOP-decode stutter you get from H.264 or HEVC sequences derived from RAW stills.
• Slideshow review on any device — drop a folder of X3F captures from a Sigma DP1 Quattro shoot into the converter, set Image Duration to 2-3 seconds, and you get a single.mjpeg playable in VLC or QuickTime on Windows, macOS, Linux, iOS, and Android without exporting from Sigma Photo Pro.
• Scientific and machine-vision archives — MJPEG is still the dominant codec in microscopy capture, machine-vision frame grabbers, and industrial inspection because each frame can be extracted losslessly without decoding a GOP. Foveon's per-pixel color makes it a natural source for documentation work; MJPEG keeps that fidelity per frame.
• IP camera and dashcam compatibility — Axis, Hikvision, and many automotive recorders still emit MJPEG streams. Converting a Foveon reference set into MJPEG produces a clip that drops into the same review tooling without re-encoding.
• Avoid generation loss across cuts — because MJPEG re-encodes only the frames you touch and never references neighbours, repeated trimming and re-export in tools like Avidemux causes far less cumulative artifacting than H.264.

X3F vs MJPEG — Format Comparison

Quality Preset Guide for MJPEG Output

MJPEG has no inter-frame compression, so file size scales roughly linearly with frame count, resolution, and quality. A 1080p Very-High MJPEG sequence of 60 Foveon frames at 5 seconds each will generally be much larger than the equivalent H.264 — that's the price of frame independence. If size matters more than per-frame access, see X3F to MP4 for an H.264 path instead.

Frequently Asked Questions

Why convert a still RAW like X3F into a video codec like MJPEG?

Because MJPEG behaves like an envelope around independent JPEGs rather than a true temporal codec. That makes it a natural carrier when you want each Foveon frame preserved as a directly-decodable image but still need a single timeline-friendly file. NLEs scrub it cleanly, frame extractors recover each shot losslessly, and unlike H.264 there is no GOP to flush before the editor can seek.

Will the converter handle X3F from every Sigma camera, including dp Quattro and SD Quattro H?

It accepts the .X3F container from the full Sigma lineup that uses Foveon — SD9 (2002), SD10, SD14, SD15, SD1, SD1 Merrill, the DP1/DP2/DP3 Merrill compacts (2012-2013), the dp Quattro series (2014-2015), and the SD Quattro and SD Quattro H (2016). Output quality depends on the original sensor data; the Quattro 1:1:4 sensor variant carries different luminance/chroma resolution than the older 1:1:1 Merrill sensor, but both decode to standard RGB before MJPEG encoding so the resulting frames look correct in any player.

Should I expect the same color depth my Foveon files have today?

No, and that's a hard limitation of MJPEG. Sigma RAWs store 12-14 bits per color layer; MJPEG is 8-bit per channel because it is JPEG under the hood. If you need to preserve the Foveon dynamic range for grading, export to X3F to TIFF first and grade from the 16-bit TIFF sequence, then render to MJPEG only as the final delivery.

What's the difference between "Merge images" and "Video per image" for X3F bursts?

Merge images takes every uploaded X3F and concatenates them in upload order into one continuous MJPEG, applying the Image Duration to every frame — useful for slideshow reels and burst playback. Video per image renders each X3F as its own short .mjpeg clip of the chosen duration — useful when you want individual ingestable clips for an NLE bin without manually splitting later.

My MJPEG file is enormous. Is something wrong?

Probably not. MJPEG ratios are around 1:20 versus uncompressed, and there is no inter-frame prediction — every frame is a full JPEG. A few dozen 24-megapixel Foveon frames at Very High will easily exceed 100 MB. To shrink the output, lower the Quality Preset, drop to a fixed 1080p preset, or use a longer per-frame duration (fewer encoded frames). For aggressive size reduction without leaving MJPEG, run the result through Compress MJPEG.

Can I play the resulting .mjpeg file directly in macOS or Windows?

Yes in most modern environments. QuickTime, VLC, MPV, and Windows Media Player with the right container all play MJPEG, and Chrome, Firefox, Safari, and Edge can decode MJPEG streams natively per the Wikipedia compatibility list. If a player refuses the bare .mjpeg extension, remux it into an AVI or MOV container with FFmpeg (ffmpeg -i in.mjpeg -c copy out.avi) — the codec data is untouched.

Does the converter actually decode Foveon RAW, or does it just embed the JPEG thumbnail?

It decodes the Foveon planes and re-renders the image at the requested resolution before JPEG-encoding each frame. The embedded preview JPEG that Sigma writes inside .X3F is not the source — using that would throw away the per-pixel color advantage of the Foveon sensor.

Is there a frame-rate setting, or does Image Duration cover it?

Image Duration is the inverse — instead of asking for fps you choose how long each frame should be visible (from 1/60 second up to 10 seconds). The converter packs the resulting frames into the stream so the playback timing matches your choice. For a true 30 fps slideshow set Duration to 1/30 second; for a 24 fps cadence pick 1/24 second.

What about audio?

MJPEG produced from still images has no audio track by default — .mjpeg is a video-only elementary stream. If you need narration or music, render the converted MJPEG into an AVI or MOV container with FFmpeg and mux in an audio file there, or convert to X3F to MOV instead, which carries audio inside the QuickTime container.