iPhone HEVC is all black in FCP X, how to fix?

Couldn’t open iPhone HEVC recordings in Final Cut Pro X properly? This post may shed you some lights on your issue. It explains a way of transcoding iPhone HEVC footage to ProRes 422 for use in FCP X smoothly.

iPhone 8 Plus’s HEVC clips in FCP X
“Hey all, I have some 4K 60p stuff taken with an iPhone 8 Plus. These clips are recorded using the HEVC format. When I import them into FCP X 10.3 on my MacBook pro 2013, I can only get audio, the video is all black. I tried to set the option “create optimized media” during the import process on FCP X, but this did not resolve the problem. Any suggestions?”
edit iphone hevc in fcp x
Apple has added HEVC support to High Sierra and iMovie, but it’s not the case of FCP X. The application will need an update for this. For now, FCP X users still need to transcode iPhone HEVC footage to ProRes format before editing. Here is a quick guide explaining how to convert iPhone HEVC H.265 files to ProRes 422 for FCP X editing.

How to encode iPhone HEVC footage to FCP X preferred ProRes 422?

Here’s what you need
HD Converter for Mac (it works well as an HEVC H.265 Converter for FCP X)
iPhone HEVC recordings in FCP X

Follow these steps:
Step 1: Install this HEVC H.265 Video Converter software on your computer, launch it and click ‘Add File’ to ingest your source media.
import iPhone HEVC recordings to FCP X

Step 2: Select ‘Apple ProRes 422 (*.mov)’ as output format for opening with FCP X
From the ‘Profile’ menu, move to ‘Final Cut Pro’ catalogue, and select ‘Apple ProRes 422 (*.mov)’ as target format. Apple ProRes is the best suited editing code for FCP X. When loading them into FCP, you needn’t wait for a long time for rendering.
import iPhone HEVC recordings video to FCP X
Important: If you’ve loaded a number of video clips to do batch conversion, please do remember ticking off ‘Apply to All’ option before you start.

Step 3: Custom video and audio settings (for advanced users)
Click ‘Settings’ button, the ‘Profile Settings’ window pops up, on which you are allowed to custom video and audio parameters like bit rate, frame rate, resolution, sample rate, and audio channels.

Step 4: Start transcoding iPhone HEVC recordings to Apple ProRes for FCP X
When ready, click ‘Convert’ to transcode iPhone HEVC files to Apple ProRes for using with FCP X. You can tick off ‘Shut down computer when conversion completed’ and go away to do other things.

Step 5: Click ‘Open Folder’ button to locate exported ProRes files
As soon as the conversion process finished, simply click ‘Open Folder’ button to get the generated Apple ProRes files. Now you are able to open them in Final Cut X for further editing without any hassles.

Also read
How do you edit DJI H.265 footage in FCP X?
HEVC in FCP X-issues editing HEVC video in FCP X
H.265/HEVC AMA plugin for Avid Media Composer
How to convert Hero 6 240 fps H.265 video to ProRes?