Although Apple claims that Final Cut Pro support processing H.264 video clips, you may encounter problems when editing some H.264 footage in FCP X, FCP 7 or FCP 6, especially the H.264 video clips from digital SLRs.In fact, the H.264 compression format is a final deivery codec, it's not an ideal one you want to use for editing. In order to get Final Cut Pro working with H.264 footage perfectly, you're recommended to transcode/prepare H.264 footage to the codec ProRes and import it into FCP 7 and X. For this purpose, this article will show you how to convert H.264 to ProRes easily and fast.
Note: This workflow can be used for any camera which capture in .mov or .mp4 container with H.264 codec. For example: Canon 5D Mark III/II, Canon T6i/T6s/T5i/T4i/T3i/T2i, Canon EOS 7D, EOS 60D, Nikon D800, Nikon D810, Nikon D5300, Nikon D3200, Nikon D4, etc. This workflow can also be used for "found footage" which is H.264 with a container of .mov or .mp4. For example, footage pulled from Youtube, Vimeo, or the iPhone 6, 6 Plus, etc.
Converting H.264 to ProRes for Editing in Final Cut Pro
The quick workaround is to use the easy-to-use yet professional app called EaseFab Video Converter for Mac which can be used as a H.264 to FCP Converter under Mac OS X 10.14 macOS Mojave, 10.13, 10.12, 10.11, 10.10, 10.9, 10.8, 10.7, 10.6, etc. It is free, clean and safe to install and use. With it, you can effortlessly transcode any H.264 footage to Apple ProRes 422, ProRes 422 HD, ProRes 422 LT, ProRes 4444 for using in Final Cut Pro and it works well and converts flawlessly.
Step 1. Import H.264 files into the Mac program
Here you can directly drag and drop the H.264 files to the converter, or click "Add Video" icon to load the H.264 video files.
Step 2. Choose ProRes as the output format
Click on the "Editing Software" and you will see options to convert your H.264 video for certain video editing software. Since you will be importing the video to Final Cut Pro after the conversion, have "ProRes" be your selected output format. You can also choose "ProRes HQ" or "ProRes LT" as the output format.
Step 3. Start H.264 to FCP ProRes conversion on Mac OS X
Now click the "Convert" button, and then leave the Mac Video Converter to do the rest automatically for you. The converter also works on MacBook, MacBook Pro, MacBook Air, iMac running Mac OS X Snow Leopard, Lion etc.
After the conversion, click "Open Folder" to locate the result videos and then you can start fun away with editing H.264 footage in Final Cut Pro X or FCP 7/6 without crashing problem and avoid rendering.