Recorded Instructional Screencasts audio to text

By Donald G. McGahan

February 11, 2018

Over several semesters I have accumulated numerous screencasts of content for courses I teach. Typically this are created when I have to be away from the classroom, usually deliver a face-to-face presentation augmented with visuals from Apple Keynote, Microsoft Powerpoint, or similar.

These generally are recorded in a relatively quite office, but are decidedly not ‘studio’ quality audio specimens. The audio pickup varies and could be from the microphone built into Apples earbuds, a MacBook Air builtin microphone, or occasionally from a Blue Yeti.

The content of the audio is decidedly science based and it is likely and speech to text program will struggle with terms and phrases specific to the scientific discipline. 

This is my solution on my MacOS Sierra system. 

First I picked up Loopback from Rogue Amoeba and installed it. 

Then I head to System Preferences and choose Keyboard. In Keyboard choose Dictation. Check the radio button On of dictation and check the Use Enhanced Dictation. An internet connection is necessary as files will be downloaded to install what it takes for offline dictation. This will allow longer passages to be transformed.

When ready to process the audio file choose Loopback from the choices under the microphone icon in the System Preferences –> Keyboard –> Dictation location.

Start Loopback and choose your source for audio. I have used VLC, Quicktime, and ScreenFlow with success. 

This is not perfect. I tend to speak without true full stops quite often. This really messes with the algorithms.