Which speech compression format to choose for training videos?

Question

MP3

For the UWP platform (Win10), possibly later for the Xamarin platform, a learning app with learning content is planned. Visually, the content looks like video clips, including stylus tracks and the speaker's voice. At the data level, these are two different streams. The audio stream contains only the speaker's speech up to 10 minutes per video. Requires random access to the sound fragment (scroll/rewind). The course includes over 10 hours of speech.
Question: What codec should be used to compress the speaker's speech? And where is the content stored? If inside the application, then you want to compress more so that the application is smaller. The app is low budget. Possibly freemium.

Answer 1

There are a lot of codecs for coding speech: https://en.wikipedia.org/wiki/List_of_codecs#Voice
You should probably proceed from which segment of devices the application is designed for. Different operating systems may support a different set of codecs.
From codecs I can offer Opus .
But as one of the most common - the MP3 format, of course.