Camtasia Studio recordings (.camrec) can be exported to MP4 video format only with the use of the original Camtasia Studio software, because no 3rd party app apparently supports Camtasia videos.
To successfully convert camrec to mp4, you can do that by selecting File ► Produce and share.. function and picking up HD item in the format selection menu. This will create an MPEG-4 video (.mp4) from your recording, typicaly in HD resolution.
As far as we know, this is the only way to achieve camrec to mp4 conversion as no 3rd party app supports Camtasia formats.
Updated: June 16, 2023