X3F to MTS Converter

How to Convert X3F to MTS Online

1. Upload Your X3F Files: Drag and drop or click "+ Add Files" to select Sigma Foveon RAW captures from your computer. Batch uploads are supported — drop the whole sequence and the tool sorts by filename.
2. Set Merge Strategy and Image Duration: Choose "Merge images" to build one slideshow MTS, or "Video per image" to emit one clip per X3F. Pick the per-frame Duration (1/60s up to 10s — 3-5s reads as a Ken Burns slideshow, 1/24s plays as a 24 fps timelapse). Set Background Color (default Black) for any letterboxing.
3. Pick Quality Preset and Resolution (Optional): Quality Preset offers Constant Quality and Constraint Quality with a Preset slider — Very High (Recommended) targets bitrates compatible with AVCHD camcorder import. Video Resolution accepts Keep original, Fixed Resolutions, or Preset Resolutions (720p, 1080p, 1440p, 2160p). Width/Height fields keep aspect ratio.
4. Convert and Download: Click Convert. Files render on our servers — no sign-up, no watermark, no quality cap. Output is an MPEG-2 Transport Stream (.mts) carrying H.264 video and AC-3 audio, ready for AVCHD-compatible workflows.

Why Convert X3F to MTS?

X3F is Sigma's proprietary Foveon RAW container. Unlike Bayer sensors that interpolate one color per photosite, Foveon stacks three photodiodes per pixel to capture full RGB at every location — the SD1 Merrill, for example, uses a 3-layer 4,800x3,200 sensor (often marketed as 46 MP). Beautiful stills, but X3F is read by almost nothing outside SIGMA Photo Pro and a handful of dedicated decoders. MTS is the camcorder-side wrapper for AVCHD: an MPEG-2 Transport Stream carrying H.264 video and Dolby Digital (AC-3) audio, jointly defined by Sony and Panasonic in 2006. Converting an X3F sequence into MTS turns stills into a video your camcorder, Blu-ray player, or AVCHD editing pipeline can ingest.

• AVCHD slideshow on a Sony / Panasonic camcorder — Pad a project memory card with an MTS slideshow that sits in the BDMV/STREAM folder alongside camera-shot clips for in-camera playback.
• Blu-ray Disc authoring — Sigma stills carry far more chroma detail than Bayer; rendering a 1080p H.264 slideshow at 16-24 Mbps lets that detail survive on a BD-R you can hand to relatives with disc players.
• Pre-edit ingest for legacy NLEs — Older Sony Vegas / Edius timelines built around AVCHD prefer native MTS over MP4 wrapping; a slideshow MTS drops straight into a camcorder bin.
• Timelapse from an SD Quattro H — Set Duration to 1/24s (or 1/30s) for a true 24/30 fps timelapse out of a Foveon sensor that has no built-in video mode.
• Archival masters of a Foveon shoot — H.264 + AC-3 in a transport stream is stream-recoverable: a corrupted middle packet doesn't kill the whole file the way it can with.mp4 (MP4 stores moov atoms that, if damaged, sink the entire container).
• Sigma Photo Pro alternative for non-photographers — Hand a relative an MTS, not an X3F they cannot open.

X3F vs MTS — Format Comparison

AVCHD Bitrate / Resolution Guide

Frequently Asked Questions

Will my Sony or Panasonic camcorder play the resulting MTS file from its SD card?

Maybe — playback depends on whether the camcorder validates the surrounding AVCHD directory tree, not just the.mts file. Sony and Panasonic camcorders generally require the full BDMV/STREAM/00000.MTS folder structure (plus CLIPINF, PLAYLIST, and an INDEX.BDM file) before they'll list a clip in playback. The MTS from this converter is the stream payload — drop it into VLC, Premiere, Vegas, Edius, or burn it to Blu-ray and it plays; in-camera playback typically requires rebuilding the AVCHD folder shell with a tool like multiAVCHD or Sony PlayMemories.

What codec and audio does the output MTS actually use?

H.264 / MPEG-4 AVC video and Dolby Digital (AC-3) audio inside an MPEG-2 Transport Stream — the codec set that the AVCHD specification standardizes. Video bitrate scales with the Quality Preset you pick; Very High targets the higher end of AVCHD-compatible rates (~17-24 Mbit/s for 1080p). AC-3 audio is added even though X3F stills carry no sound, because Blu-ray and AVCHD demuxers expect a populated audio track.

Why a slideshow and not just a single still?

X3F is an image; MTS is a video stream. Converting one X3F to "MTS" means encoding a still frame as a 1-frame H.264 stream, which most AVCHD parsers reject as malformed. Setting Duration (e.g., 5 seconds per frame) repeats the frame for that interval so the output is a valid video that Blu-ray players and camcorders accept. If you batch multiple X3F files with "Merge images," you get one continuous slideshow MTS.

How big will the output file be?

Roughly Duration x bitrate. A 10-image slideshow at 5s each (50s total) at 24 Mbit/s = ~150 MB. A 30-minute 1080/60i AVCHD slideshow at 24 Mbit/s lands around 5.4 GB — well within a single-layer Blu-ray's 25 GB and far above the ~4.7 GB of a single-layer DVD-R (where you'd want to drop to AVCHD-on-DVD's 18 Mbit/s ceiling).

Can I keep the full Foveon resolution in the MTS?

No. MTS / AVCHD caps at 1920x1080, so a 4,800x3,200 (SD1 Merrill) or 5,424x3,616 (sd Quattro H) frame is downscaled. If you want full-resolution stills preserved for prints, develop the X3F to 16-bit TIFF in SIGMA Photo Pro's Super-Hi mode first; use MTS only for the slideshow video. For larger-than-1080 video output, render to MP4 instead — see X3F to MP4 — which has no AVCHD-imposed resolution ceiling.

Should I pick "Merge images" or "Video per image"?

Merge images concatenates every uploaded X3F into one slideshow MTS — the right pick if you want a single file to drop on a Blu-ray or hand off to a relative. Video per image emits one MTS per source X3F — useful when you want to ingest separate clips into an NLE timeline and re-order them on the editing pad, or when each frame needs its own clip metadata for the camcorder.

Why MTS and not MP4 for this workflow?

MP4 (H.264 in an MP4 container) is fine for web and phones but rejected by older AVCHD camcorders and many consumer Blu-ray players that demand an MPEG-2 Transport Stream. MTS also resyncs better when a packet is damaged mid-file. If you want broad device compatibility instead of camcorder/Blu-ray fidelity, use X3F to MP4 or X3F to MOV. For the reverse direction (MTS playback on phones), see MTS to MP4.

Does converting to MTS lose color information from the Foveon sensor?

Yes — substantially. X3F stores full 3-channel data at every photosite (Foveon's defining trait); the H.264 chroma subsampling inside AVCHD is 4:2:0, meaning chroma is sampled at one-quarter resolution relative to luma. You also lose any bit-depth above 8-bit per channel. If color fidelity is the priority, develop the X3F to 16-bit TIFF first, retouch, then encode the slideshow — that limits the loss to the H.264 step instead of compounding it with X3F's native quirks. The result still looks visibly cleaner than a Bayer-sourced slideshow at the same bitrate.

Are my files private?

Files are uploaded only for processing and tied to your browser session. There's no public listing, no account required, and no watermark on output. For sensitive shoots, close the tab when done; the server-side copies are purged on the standard retention schedule.