Android has a useful, simple audio recording application built-in since Android 7.
- an audio recorder for little money (£€30-40).
- a Galaxy Samsung SIII, S4, S5 with the default recorder app from lineageos
- TP8 Telephone Pick-Up to record interviews done via mobile (software solutions are flaky or proprietary)
Audio recorder on GNU/Linux
To record a conversation over jit.si for instance
- apt-get install simplerecorder
- simplerecorder # test it before the real interview, the interface is not super intuitive and it's easy to get it wrong
If the volume of the recording is too low, it can be amplified with:
ffmpeg -i interview.mp3 -filter:a "volume=5.0" amplified.mp3
Two very good tools for helping with transcribing interviews are: