FCPX filmstrip missing for Canon R6 Mark III HEVC import

OK, after lots of study, here is the situation: When the FCP Media Import Window is up and you click on a clip, there are a series of internal plugins called RAD (Random Access Device), one for each supported card-based media type. The current ones are:

P2AVF.RADPlug

XDCAM.RADPlug

MPEG4.RADPlug

AVCHD.RADPlug

MPEG2.RADPlug

Archive.RADPlug

Each one checks the folder tree for the given media type. Some check for multiple tree formats. E.g, an .mp4 file from a Sony A7SIII is checked by MPEG4.RADPlug. It looks for certain things such as whether the tree PRIVATE/M4ROOT/CLIP exits. If it passes those checks, then range-based selection on the filmstrip is permitted, hence range-based import. If not, then you cannot select or import a range.

That same plugin also checks for other Panasonic GH series (via PANA_GRP) and any camera using DCIM

with MP4.

Likewise, with MXF files contained in their folder tree from the Sony FX6, FX9, etc. Those are checked by XDCAM.RADPlug.

Canon's XF-AVC format (XFVC/CANONMSC/REEL_xxxx/) is not in any plugin's recognition list, so Canon XF-AVC cards (R6Mk3, R5C, C70 in XF-AVC mode, etc.) do not have range-based import from the FCP Media Import Window.

I don't know why no FCP RADPlug file exists for the Canon formats. You can submit an enhancement request at Apple's FCP feedback site. FCP development has repeatedly stated they read each one:

Feedback - Final Cut Pro - Apple

This situation is sometimes encountered because almost no product reviewers test things like this. With my team's FX6 cameras, the MXF format supports timecode and other metadata much better than the MP4 formats from the mirrorless cameras. Yet you'll never hear a YouTube reviewer mention that. As part of our purchasing decision, we spoke with other professional users having extensive post-production experience. That's how we found out, not from superficial YouTube reviews.

I personally never use the FCP media import window, because I've already located the media in Finder and I don't want to do that a second time. Also, we always import with "leave files in place" so it doesn't take extra space.

However, before importing to FCP, you can use QuickTime Player to do "no encode" lossless trims of most video formats. It is lightning fast and preserves all the metadata. It can also delete chunks from the file and re-order those. It is safe because it operates only on a copy of the file, not the original. For details, go to YouTube and search for "How To Cut Out and Save a Portion Of a Video."

The R6 Mk3 is a new camera. It is not yet listed by Apple as a supported camera: Cameras supported by Final Cut Pro - Apple Support

Since new cameras often use novel metadata or encoding methods, it is very difficult to investigate these without unmodified samples from that new camera. I looked around for a while and finally found some video samples from the R6 Mk3, including some that were HEVC 10-bit MP4.

They seemed to work OK on my M1 Ultra Mac Studio running macOS Tahoe 26.4 and FCP 12.0. This includes drag/drop from Finder and using the FCP import dialog. However, these samples I found were just .mp4 files, not the card folder structure.

If there are problems with HEVC clips unique to the card folder structure on the Canon R6 Mark III camera, we would need the full folder structure posted on a downloadable file-sharing site for investigation.

I examined the folder structure you uploaded, plus individual MXF clips from an R5C and MP4 clips from a Sony A7SIII (in the card folder structure). There are cases where the FCP Media Import window will permit importing a range from a clip and other cases where it will not. It's not just the R6 Mk3.

Testing this is difficult since it requires card folder trees from multiple cameras and formats. I never use the FCP import dialog so I don't have much first-hand experience with it. I only use drag/drop from Finder and only using "Leave Files in Place."

The FCP manual says, "Some import options are available only when you import files from a storage

device" (probably meaning a card). I'm now trying to determine the gating logic FCP uses for permitted import actions when using the Media Import Window.