What types of audio and video files can be imported?

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).

There are some additional enhancements for these professional file formats:

Broadcast Wave 
SpeedScriber reads the start timecode (BEXT or iXML) and iXML channel names if present.

MXF
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.