I have a 1080p24 video rendered out with the Avid DNxHD codec on a PC using Premiere. When I bring it over onto my Mac workstation that has FCP X and drag it onto a timeline the preview pane is just red with "Codec could not be opened". It seems that Final Cut Pro can't support DNxHD codec. I have scoured the internet, tried everything I could find about the DNxHD to FCP. The final result I found from all relevant forums is that we need convert DNxHD to ProRes for Final Cut Pro native editing.
Actually, FCP X does support DNxHD if it is rewrapped as QT/MOV and if the Avid QuickTime Codecs LT plug-in is installed. If you didn't install the plug-in correctly or got some DNxHD MXF files, a better solution is to transcode DNxHD to ProRes. Here you can complete the DNxHD to ProRes lossless conversion with the help of Brorsoft Video Converter for Mac.
Overall, the program is a professional yet all-in-one video conversion tool. With it, you can easily convert all DNxHD files to ProRes 422, ProRes 422 HQ or 4444 for using in Final Cut Pro X/7/6. Besides, the Mac video converter can convert MKV, AVI, WMV, MPG, VOB for editing in Final Cut Pro, Final Cut Express, iMovie, Avid MC, Adobe Premiere Pro etc. Some simple video editing functions like trim, crop, watermark are also provided for you. Just download it and follow the tutorial below to convert DNxHD to Apple ProRes for FCP.
Converting DNxHD to ProRes on Mac OS X
Install the DNxHD to ProRes converter program on Mac and run it. Drag the Avid DNxHD files to the software. Or you can also click "Add" button on the top of the main interface to import video to the app.
Step 2. Select output format
Hit the "Format" bar and select Final Cut Pro > Apple PreRes 422(*.mov) as output format. This format is specially designed for FCP X.
Tip: Adjust the video and audio parameters, including the Bitrate of Video & Audio, Video Size, Sample Rate, Frame Rate, Audio Channels, etc., by clicking the Settings button on the main interface for getting the best quality.
Step 3. Start conversion
Tap "Convert" button on the main interface to start DNxHD to ProRes conversion on Mac OS X. After the conversion, it is easy to import the transcoded DNxHD videos to Final Cut Pro X or FCP 7 for further editing.
How to import different videos, codecs to Final Cut Pro X
Transcoding XAVC/XAVC S to ProRes for FCP
Convert AVI/MKV/MP4/MPG/VOB etc. to Apple ProRes
Transcode H.264 videos to ProRes for Final Cut Pro