Every format, and exactly what CoreTrim does with it.

Video — QuickTime & MP4

.mov · .mp4 · .m4v

Timecoded MP4 sources — DJI Osmo and Action cameras, and any camera that writes a timecode track into MP4 — are trimmed into a QuickTime .mov file so the timecode survives. The video and audio are the same bytes; only the wrapper changes.

Other video that Final Cut Pro can read is also trimmable by re-encoding to ProRes — offered only with your approval, never automatically.

Video — Professional MXF

.mxf — broadcast & cinema cameras

Video — AVCHD / camcorder

.mts · .m2ts

Camcorders space their true random-access frames further apart than most formats — about ten seconds on the cameras we tested — so an AVCHD trim starts at the keyframe just before your edit and carries a little more footage than a ProRes trim would. It is still lossless, and it still plays from your exact in-point. Two kinds of recording are copied instead: those with Dolby Digital (AC-3) audio, which has no lossless trim route, and those that carry no keyframes mid-file, where there is nothing to trim to. Both are named as such in your report.

Video — camera RAW

.r3d · .rdc · .braw

RED footage is trimmed using RED's own SDK, so what comes out is RED-native media — frame-exact, and carrying the clip's .RMD look settings so it grades in Final Cut exactly as your original does. Takes recorded across several files travel as complete sets, so nothing is left behind. Other manufacturers' RAW is copied in full instead — ARRIRAW, Canon Cinema RAW Light, Sony X-OCN, Panasonic V-RAW, and Nikon's N-RAW and R3D NE — because those formats need their maker's own software to open. Apple ProRes RAW trims like any other ProRes.

Blackmagic RAW is trimmed with Blackmagic's own SDK — native BRAW, frame-exact, with the clip's .sidecar look file carried beside it. RAW adjustments made in Final Cut's Edit RAW Properties live in the library, not in the media, so they don't travel with an export; the READ ME and report say so.

Audio

.wav · .aif · .aiff · .caf · .m4a · .mp3

What the terms mean

Five words, used precisely, throughout this page

Lossless

No re-encoding — the trimmed media is bit-for-bit the same quality as your original.

Frame-exact

Trimmed precisely to your edit points.

Keyframe-aligned

Long-GOP formats start at the nearest keyframe just before your edit (a fraction of a second). Still lossless, and your clip plays correctly from its exact in-point.

Sample-accurate

Audio is trimmed to the exact sample.

Re-encoded

Compressed audio is re-encoded to AAC (the only quality-affecting case above).

Cameras that trim

Common cameras & the formats CoreTrim trims from them

Timelines & multicam

CoreTrim trims your media however your timeline uses it

When a clip is copied instead of trimmed

All safe — the clip is copied in full, never altered

• The clip is offline, or CoreTrim doesn't have permission to read it.
• Your timeline already uses the whole clip — there's nothing to trim away — or trimming it would save so little that copying is the better deal. CoreTrim tells you which, and you can still choose to trim.
• It's a still image, or camera RAW from a manufacturer's own format — ARRIRAW, Canon Cinema RAW Light, Sony X-OCN, Panasonic V-RAW, Nikon N-RAW and R3D NE. These need the manufacturer's own software to open, so CoreTrim copies them untouched. REDCODE RAW, Blackmagic RAW and Apple ProRes RAW are the exceptions — all three trim.
• It's a specialized or unsupported source format.

And if a file can be neither trimmed nor copied — a damaged or unreadable source — CoreTrim leaves it out of the export and says so plainly in the report, rather than quietly linking your new project back to the original media.

Any format not listed on this page is copied in full and relinked into your trimmed project — intact, never altered, never lost. CoreTrim never modifies your original media. Updated September 2026 · CoreTrim 1.2