Microphone audio source is capturing system audio

[Abishek-project]

Using Microphone audio source (Attached the recording)

issue-demo.mp4

Normally, when the audio source is microphone, the recording should capture only microphone input.
However, on Pixel 6 (Android 15) the recorded output also contains YouTube audio (system audio) - maybe it's capturing the system audio via mic , (maybe AEC is not working)
But, when wired headphones are connected, the recording behaves correctly and only the microphone audio is captured.

Device Information:
Device: Pixel 6
Android Version: 15
Library: RootEncoder
Audio Source: Microphone

Steps to Reproduce

1. Start recording using microphone audio source.
2. Begin speaking.
3. Move the app to the background.
4. Play a video on YouTube.
5. Continue speaking while YouTube audio is playing.
6. Stop recording.

Actual Behavior
With Speaker:
Both microphone audio and YouTube audio are recorded.

Expected Behavior
Since the audio source is microphone, the recording should capture only microphone input.

[SreenuvasulaReddy]

@pedroSG94 could you please check and update

[Prathiv7]

@Abishek-project @pedroSG94 I can able to reproduce the issue in Moto g32 , iqoo7.
only on Samsung s20 it's not recording the system audio with microphone source

[pedroSG94]

Hello,

It is normal and should be fixed this way:
1 - Enable noisesuppresor and echocancelation in the prepareAudio method
2 - Change the microphone source in the MicrophoneSource constructor to MediaRecorder.AudioSource.VOICE_COMMUNICATION (this should do the same that the case 1)

If should works but sometimes the AEC of the device is bad or not available.

[Prathiv7]

@pedroSG94 Okay and I have another doubt - is this best config ?

genericStream.setTimestampMode(TimestampMode.CLOCK, TimestampMode.BUFFER)

and also when we use MixaudioSource the v face same audio issue as mic is capturing the system audio again . it's like MicrophoneSource itself acting like MixaudioSource . V tested this even with costly phones like Samsung S23 , ultra still same . but with Samsung S20 MicrophoneSource didn't capture the system audio and it's so so clean like IOS phones .

in the MixaudioSource the Mic already has the system audio and it again mix the system audio and it's causing extra noise .
Can't v do something like if the mic already capture the system audio then let's not mix system audio again ?

[pedroSG94]

Hello,

Did you tried my previous suggestions and you still have problems? Also, you can use both at the same time
Microphone is capturing the audio from speakers, you can check it if you reduce the volume.
I have no way to avoid it except with the previous suggestions. For the same reason I have no way to check if you get audio from speakers and fix it when I'm mixing because I have no way to detect it

[Prathiv7]

I'm getting a pop sound in the recording . Yes I tried previous suggestions. happy to share the source code if needed

[pedroSG94]

Hello,

If the recorded audio is recorded in local (using startRecord of the library):

Try to reduce the device audio to minimal or even disable it to discard that the problem is related to get the audio from speakers. If it is related with speakers and you have the suggestions changes added and tested all possible cases (like only enable echo cancellation, only enable noise suppressor, both enabled but using default source instead of VOICE_COMMUNICATION, etc) the problem will be really complex because you need a filter of audio.
If the problem is only using the previous changes but you haven't pops without it, it is normal. Sometimes AEC or noise filters works very bad in fews devices.

The main problem in android is that not all devices have a good AEC implemented in the microphone so an audio filter is necessary and it is complex to do (I don't know enough about audio to create it).

If the audio is recorded in server side using the stream received this could be a problem with the timestamp. I'm currently working on PRs with changes that could help.

[Prathiv7]

okay thx for the update