MOS to HEVC Converter

Convert MOS to HEVC Online

A MOS is a medium-format RAW photograph from a Leaf or Mamiya Aptus digital back — a single, very high-resolution still — while HEVC (H.265) is a modern video codec. This converter renders that one RAW frame and encodes it as a silent, motionless H.265 clip that simply holds the photo on screen. Be honest before you start: this is an unusual target. If you want a normal viewable picture, convert MOS to JPG; if you want the still as a clip that plays nearly everywhere, MOS to MP4 is a far safer choice than a bare HEVC stream. Pick HEVC only when a specific H.265 pipeline requires the raw .hevc extension.

How to Convert MOS to HEVC

1. Upload Your MOS File: Drag and drop your .mos file or click "+ Add Files". A medium-format MOS is large, so the main wait is the upload, not the conversion.
2. Set Image Duration: Use Image Duration (default 5 seconds per frame) to choose how long the still is held on screen — this sets the length of the output clip.
3. Pick Quality, Background, and Resolution (Optional): Leave the Quality Preset on Very High (Recommended), set a Background Color (default Black) for any letterbox area, or choose a Video resolution preset to scale the frame down. The Video Codec is fixed to H.265 (HEVC) for this output.
4. Convert and Download: Click "Convert" and download your HEVC file. No sign-up, no watermark.

MOS, HEVC, and the Better Alternatives

Frequently Asked Questions

Should I convert MOS to HEVC at all, or to MP4 or JPG instead?

For almost every purpose, no. A MOS is a high-resolution medium-format RAW still and HEVC is a modern video codec, so this pairing mismatches twice over — a still frozen into video, and a premium studio RAW aimed at a codec whose motion-compression benefits never apply to a single frame. If you want to view, print, or share the photograph, convert MOS to JPG. If you want it as a playable clip, MOS to MP4 writes an H.264 file that plays on phones, browsers, and editors everywhere. A related MOS to M4V covers Apple-centric workflows. Choose HEVC only when a specific H.265 system insists on the raw .hevc extension.

Does the HEVC file contain any motion or sound?

No — it is a silent, single-frame clip. A MOS is one still photograph, so the converter holds that one rendered frame for the Image Duration you set, with no panning, animation, or footage to recover, because none exists in the source. A still also carries no audio data, so although an HEVC stream can be paired with an AAC track in a container, this converter writes no audio for an image source — the output is silent by design. To build a moving sequence you would upload several MOS files and choose the Merge images strategy, but even then it is a slideshow of stills, not real footage.

Will I lose image quality going from a medium-format MOS to HEVC?

Yes, substantially, and it is inherent to the conversion rather than a tool flaw. A MOS holds untouched high-bit-depth (16-bit per channel) sensor data on a TIFF base that must be demosaiced and tone-mapped before it is viewable, and that render bakes in white balance, exposure, and color — the editing latitude that is the entire reason to shoot medium-format RAW. A Leaf Aptus back commonly captures 40-80+ megapixels; that frame is then scaled down to a video size, discarding the vast majority of the resolution. Keep the master MOS for any future editing — the HEVC clip is a delivery file, not an archive.

Why won't my .hevc file play in most apps and browsers?

Because a bare .hevc file is a raw H.265 elementary stream with no container — just the coded video data, typically with Annex B start codes — so many players that expect an MP4 or MKV wrapper refuse to open it. On top of that, H.265 playback itself is uneven: Safari supports it (version 13+), while Chrome, Edge, and Firefox only added partial, hardware-dependent support in recent versions and older builds reject it entirely. H.265 is also patent-encumbered, licensed across multiple pools (MPEG LA, Access Advance, and Velos Media), which is part of why support stayed patchy. If you need broad playback, convert MOS to MP4 instead. In our testing, a raw .hevc rendered from a single Leaf MOS opened in VLC but would not play directly in Chrome, exactly as expected for a container-less H.265 stream.

Is HEVC's better compression any use for a single still?

Not really. HEVC's headline advantage is roughly 25-50% better compression than H.264 at the same quality, but that efficiency comes from how it predicts motion between frames — and a MOS conversion has only one frame and no motion. So you pay HEVC's costs (slow software encoding, patchy playback, complex licensing) without gaining its main benefit. For a still-as-video, H.264 in an MP4 is smaller in hassle and plays everywhere; for the photo itself, a JPG is the right tool.

What happens to my uploaded MOS file after conversion?

Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after the conversion — no sign-up, no watermark, never shared or made public.