SpeedScriber can import any audio or video file that can be played in QuickTime Player.
An unsupported codec message will be displayed in the SpeedScriber viewer for any file that isn't supported by Apple's media frameworks, e.g. RED (.r3d) or 10-bit H.264 (as created by Panasonic GH5).
There are some additional enhancements for these professional file formats:
On macOS 10.12 Sierra (or later), SpeedScriber can import and play MXF files if the Apple Pro Formats codecs (version 2.0.5 or later) are installed, which require installation of Apple Compressor, Final Cut Pro or Motion. NOTE: There is currently a severe performance issue with MXF files which we've reported to Apple, so you may find MXF files are unusable.