Kiran,
I never used audio recording, these links can be useful for you. External app for audio recording , audio quality.
One thing which I would like to add according to ERB you can not take an audio recording of any interview. It will breach the PII of the respondents.
Best,
Narendra
Helou Kiran, I will tell you about my experience, some years a go I need an app external for record the interview (du record) this app can save in video the interview for audit purposes, 1 interview of 15 minutes aprox is 15 MB, then when interviewer has 10 interviews need almost 150 mb in the device (tablet or cell phone) , and the send this amoung of files is very heavy, this video is independent of the survey, then with the CENTRAL SERVER I can use the option of audio, with the parameters quality=normal, with this option the interview record the survey and send the CENTRAL SERVER, the audio file is very small, the same interview of 15 mins has got only 1.2 MB, when the interviewer send the survey send too the audio file, I used this option in the initial survey, the interviewer need to authorize the record of the interview, for some countries this method of interview is forbidden, the interview can cancel the record in any part of the interview, then the audio only has a part of the interview, once the project is finished you can download all audio files, with the extension amr, I use VLC MEDIA PLAYER for listener. A very important thing is that recording init in the first screen of survey, then, if the intervierwer stays in the first screen the audio recorder init and finished at last screen of interview, on some occasion 1 had a 4 hours of audio file (25 MB) but only the last 10 minutes is for the real interview.
https://docs.getodk.org/form-question-types/#using-the-built-in-audio-recorder
