X3F to HEVC Converter

How to Convert X3F to HEVC Online

1. Upload Your X3F Files: Drag and drop or click "+ Add Files" to select one or more Sigma Foveon RAW files from your computer. Batch upload is supported — every X3F you add becomes one segment of the output slideshow (or one standalone.hevc per file if you pick "Video per image").
2. Pick Merge Strategy and Image Duration: Default merge is "Merge images" (one slideshow) — switch to "Video per image" if you want each X3F as its own.hevc. Set Duration to 1, 2, 3, 5, 7, or 10 seconds per frame (5 seconds is the default). Background Color fills any letterbox area; default Black matches most playback environments.
3. Tune Resolution, Preset, and Quality (Optional): Pick Video resolution mode — "Keep original" preserves the X3F's native pixel grid (e.g., 2268x1512 on SD9/SD10, 4704x3136 on Quattro), "Preset Resolutions" snaps to 720p/1080p/1440p/2160p, or "Fixed Resolutions" lets you type Width x Height. Quality Preset chooses Constant Quality (CRF, target visual quality regardless of size) or Constraint Quality (bitrate-bounded). The Preset slider defaults to "Very High (Recommended)" — drop to Medium or Low if you need a smaller file.
4. Convert and Download: Click "Convert" to produce a raw HEVC elementary stream (.hevc, Annex B byte-stream per ITU-T H.265). Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

Why Convert X3F to HEVC?

X3F is Sigma's proprietary RAW format for cameras built around the Foveon X3 sensor — a three-layer stacked-photodiode design that captures full red, green, and blue at every pixel location instead of interpolating from a Bayer mosaic. Sigma introduced X3F with the SD9 in 2002 and has used variants in every Foveon body since: SD10, SD14, SD15, the SD1/SD1 Merrill, the DP Merrill and DP Quattro compacts, the sd Quattro/Quattro H mirrorless line, and the fp/fp L (when shooting in Sigma's CinemaDNG-or-Foveon RAW mode on Foveon bodies). Converting a stack of X3Fs into an HEVC bitstream gives you a single compact, hardware-decoded clip suitable for review, sharing, or further editing — typical use cases:

• Foveon contact sheet for client review — One 5-second-per-frame.hevc of 24 shots reviews in 2 minutes; Foveon's per-pixel color shows up cleanly at 1080p HEVC, where Bayer demosaic artifacts would otherwise be invisible.
• Stop-motion or time-lapse from a Sigma DP/Quattro — The DP2 Merrill, DP3 Quattro, and sd Quattro shoot at 14-bit per channel; encoding the sequence to HEVC at CRF 18-22 preserves shadow gradation that an 8-bit MP4 of JPEGs would crush.
• Editor proxy clip — Feed the.hevc into DaVinci Resolve, Premiere Pro, or Final Cut Pro as a low-cost proxy while the original X3Fs stay archived; HEVC hardware decode (Intel Quick Sync, NVENC, Apple VideoToolbox) keeps timeline scrubbing snappy on a 4K project.
• Storage-efficient archive of a Foveon shoot — A Quattro X3F can be 40-55 MB; a 100-frame HEVC slideshow at CRF 24 typically lands under 50 MB total, useful for handing off a "look at this" file without zipping the originals.
• Background loops and gallery monitors — Output a 4K HEVC at 5 seconds per image with Black background and play on a Smart TV, Apple TV, or AndroidTV that ships with hardware HEVC since the H.265 decoder requirement landed in HDMI 2.0a-era silicon (~2015).

X3F vs HEVC (.hevc bitstream) — Format Comparison

HEVC Quality Preset Guide (CRF)

Frequently Asked Questions

Why does the.hevc file not play in VLC or Windows Media Player?

A.hevc file is a raw H.265 elementary stream — just a sequence of Annex B NAL units with no container, no timestamps, and no index. Most consumer players (VLC, MPC-HC, Windows Media Player, QuickTime) expect HEVC inside MP4, MKV, or MOV. To play locally, either use a bitstream-aware tool like dec265 from the libde265 project or remux the.hevc into MP4 with FFmpeg: ffmpeg -framerate 1 -i input.hevc -c:v copy output.mp4. If you want a playable container directly, use the X3F to MP4 converter instead.

Which Sigma cameras produce X3F files this tool accepts?

Every Foveon-sensor Sigma body since 2002: the SD9, SD10, SD14, SD15, SD1 and SD1 Merrill DSLRs; the DP1/DP2/DP3 and their Merrill and Quattro revisions; the sd Quattro and sd Quattro H mirrorless. The fp and fp L use Bayer sensors and write DNG, so those aren't X3F. If your file starts with the ASCII signature "FOVb", it's a valid X3F and the converter will read it.

Does the converter preserve Foveon's per-pixel color advantage?

Partially. Foveon's three-layer stacked photodiode captures R, G, and B at every pixel, which gives unusually clean color microcontrast in the source X3F. HEVC then encodes that as YUV 4:2:0 by default, which subsamples chroma 2x in both dimensions — so the per-pixel color advantage is reduced once you hit the video step. For maximum fidelity, use a low CRF (18-22) and keep the original resolution; if you have an HEVC pipeline supporting 4:4:4 you'll preserve more, but most consumer hardware decoders only handle 4:2:0.

How long should each X3F display in the output video?

It depends on viewer attention. For a quick contact-sheet review (you, the photographer, scrubbing through 200 shots) try 1-2 seconds. For client review where someone is judging composition and color, 3-5 seconds works (5 is the default). For a gallery loop or projected display set 7-10 seconds so each image has time to register. The duration directly multiplies output length: 100 X3Fs at 5 seconds each = an 8-minute clip.

What happens if my X3F files have different resolutions?

Mixed-resolution input is handled by the resolution mode you choose. "Keep original" letterboxes smaller frames inside the largest frame's canvas, filled with the Background Color you picked (default Black). "Preset Resolutions" and "Fixed Resolutions" rescale every frame to the same target — the cleanest option for mixed SD9 (2268x1512) and Quattro (5424x3616) batches.

Should I pick Constant Quality (CRF) or Constraint Quality?

Pick Constant Quality when you care about visual quality regardless of file size — this is best for archival and editor proxies. Pick Constraint Quality when you have a target bitrate (for streaming, attaching to email, or fitting a specific budget). CRF varies file size to hit a quality target; Constraint Quality varies quality to hit a size/bitrate target.

Can I use this as a hand-off to a video editor instead of converting X3F to TIFF first?

Yes, with a caveat. Sending an HEVC proxy into DaVinci Resolve, Premiere Pro, or Final Cut Pro is faster and uses less disk than exporting 100 TIFFs from each X3F. But if you need to recover Foveon's full per-pixel color in grading, the TIFF route preserves more — develop the X3Fs with Sigma Photo Pro to 16-bit TIFF first, then build the timeline. The X3F to TIFF converter handles the still-image stage.

Why is HEVC better than H.264 for a Foveon-source slideshow?

HEVC (H.265) typically delivers roughly 40-50% smaller files than H.264 at similar perceptual quality, and it handles high-bit-depth (10-bit) and 4K content more efficiently — both relevant when your source is a 14-bit Foveon RAW with subtle color gradation. The trade-off is encoding takes longer and older hardware (pre-2015 GPUs, some older smart TVs) lacks hardware decode. If you need maximum playback compatibility, use H.264; if you want a smaller archive, HEVC wins.

How does this compare to converting other RAW formats to HEVC?

The pipeline is the same as our ARW to HEVC converter for Sony or other RAW-to-HEVC paths: the source RAW is developed to a frame buffer and that buffer is fed to the H.265 encoder. The output is identical in structure regardless of input RAW format. The only thing that changes is the color science of the source — Foveon's stacked-photodiode color tends toward cooler greens and richer blues than Bayer sensors at the same color temperature, which carries through into the HEVC output. If the output file is larger than you'd like, run it through compress HEVC at a higher CRF.