The RMF file (.rmf)

RMF stands for Raw Media Format: Canon's container for Canon RAW, the raw video output of its first Cinema EOS cameras built for raw. Canon announced the EOS C500 in 2012 as a 4K camera that records "in RAW mode at 10-bit depth without de-Bayering" to external recorders. Those recorders save each frame of the clip as its own RMF file.

Later, the EOS C700 family recorded Canon RAW as RMF too: Canon lists "Canon RAW .RMF" among its recording formats, at 10 or 12 bits with Canon Log 2, written either to the Codex CDX-36150 recorder that attaches to the camera or to an external recorder over 3G-SDI. The camera's own CFast cards record only compressed formats.

Canon's newer cameras record a different raw format internally: Cinema RAW Light, in CRM files. RMF is the older, uncompressed, externally recorded format. Software that reads one usually reads the other.

Like a camera raw photo, a Canon RAW frame keeps the sensor's colour filter pattern: one value per photosite, before the debayering that turns it into full-colour pixels. Unlike most photo raw formats, more has already been decided in the camera:

• ISO and white balance are applied before the data leaves the camera. You can still adjust them in post, but as a grade, not by changing how the raw data is read.
• A log curve is applied: Canon Log on the C500, Canon Log 2 on the C700. AbelCine noted that this makes the files behave in DaVinci Resolve much like DPX log files, with a consistent range of stops above and below middle grey across ISO settings.
• Nothing is compressed. Every frame takes the same space, which keeps playback simple but makes the data rate very high.

Opened without a viewing LUT or colour transform, Canon RAW looks flat and grey, as any log footage does. Cinema RAW Development and Resolve apply a Canon colour pipeline to show it as intended.

Canon's list of cameras supported by Cinema RAW Development covers the C700 and C500 families alongside the newer CRM cameras, but Canon doesn't say which of them write RMF. Treat the table as the cameras documented here, not necessarily a complete list.

• Cinema RAW Development (Windows and macOS, free from Canon): Canon's own software for developing, playing and exporting raw clips from its cinema cameras. Version 2.12.0 (March 2025) supports the C700 and C500 families among others, and reads both RMF and CRM clips.
• DaVinci Resolve: has read RMF since version 9.0.3 (2012); Blackmagic's codec list for Resolve 20 includes RMF on macOS and Windows. Resolve can debayer, grade and export to any delivery format.
• Other tools: most general video players and editors can't open RMF at all. Transcode in Resolve or Cinema RAW Development first.

Canon doesn't document the byte layout of RMF, its file signature, or exactly how each recorder names and nests the files. Open-source tools such as ExifTool and LibRaw don't decode it either. To identify RMF files in a script, rely on the extension, the folder structure and the XML files rather than the bytes.

• A player or editor won't open the file. Almost nothing outside Canon's software and DaVinci Resolve reads RMF. Transcode the clip in one of those first.
• Only one frame appears, or a still image. You opened a single RMF file. Open or import the clip folder instead.
• The picture looks flat and grey. That's Canon Log. Apply a Canon colour transform or LUT in Resolve or Cinema RAW Development.
• The clip has no sound. The audio is in separate files in the clip folder; make sure they were copied with the frames.
• Storage fills up fast. Uncompressed 4K Canon RAW runs at about 16 GB a minute. Plan for it, or transcode for editing and keep the RMF clips as camera originals.