Tell me how to control microphone's volume on ChromeOS automatically

[Hisako Yamaji]

Thank you for your help. We are developing an Android application that records and analyzes the voice input from the microphone for elementary school students who are learning English. We are using the headset by pointing the voice input/output terminal on the Chromebook device.

However, immediately after inserting the headset, the input level of the microphone becomes the maximum state, and when recording, the voice input level is too high and severe sound distortion occurs in the recorded data, so it is not suitable as a material for voice analysis. This will result in inappropriate audio data.

I have already confirmed that Chromebooks have a slider UI that allows us to adjust the audio input level, but adjusting it every time after inserting the headset is a heavy task for a child learner, so I don't want to do it manually. We would like to avoid the adjustment by hand , and We would like to automatically adjust the audio input level to an appropriate level.

On Android devices we can adjust the audio input level using the "setStreamVolume method of the android.media.AudioMamager class", but on Chromebooks this is not possible according to https://developer.android.com/guide/topics/media-apps/volume-and-earphones?hl=ja Chromebook is a fixed volume device, so it is not possible to adjust the audio level with this API. We tried LibwebRTC AGC library in vain.

Could you tell me how to adjust the Chromebook's audio input level from some app or script? It doesn't matter if we use the Android app or the Chromebook app. 　The target Chromebook terminal is NEC Chromebook Y2. The Chromebook Y2 has extremely high audio input levels when using a headset, Even if the microphone volume from the headset is set to about 30%, the sound still cracks, and at about 15% the sound is heard at a level that does not crack. it's very troublesome.