[Feature / Question] Allow third party call recorder app "real" call recording

[ElsAr4e]

Since Android 10+ third party call recorder apps can't have "real" call recording (without root) because Google blocked the possiblity. Regular Android OS can only use the accessibility service to record calls -but this won't work especially if you use headphones.

But since GrapheneOS is an Android fork and a custom ROM could you add the possiblity that third party call recorders can access the audio of a regular cellular phone call / the VOICE_CALL stream (without root) - for example create settings of GrapheneOS with opt-in settings per app to allow special access without root?

Would that be technically possible that GrapheneOS (even based on Android 10+) allows third party call recorder app "real" call recording (without root)?

(I know GrapheneOS now has now a native inbuilt call recorder app but I would also like to use third party apps to record calls.)

Similiar options when it comes to VOIP call recording?

[thestinger]

It's provided by accessibility services without any significant limitations. The Play Store doesn't allow apps to use accessibility services without an accessibility use case they consider valid. That's a policy restriction for the Play Store, not a technical restriction. Accessibility services don't have a limit on what's considered a valid purpose at an OS level, only at a store policy level. This can definitely be done with them already. It's the only approach available to implement it. Using the functionality we've included in the included dialer app is what we recommend, and that can be improved rather than adding support for sketchy third party apps obtaining more data. That's the opposite of what we do in GrapheneOS.

Similiar options when it comes to VOIP call recording?

This doesn't involve most of the OS calling infrastructure. If you wanted to record WhatsApp calls, that requires a custom WhatsApp client supporting it or an accessibility service which understands WhatsApp enough to do this. An accessibility service can capture the audio from the microphone and what's being played by the app. It would be a mess to implement with an accessibility service but it's possible. There's not really anything the OS can do to make this easier. It's not the OS call infrastructure.

[ElsAr4e]

Thank you for your fast answer and explanation.

But I thought if you use accessibility services to record a call - even if GooglePlay would allow that - you can't have "Real two-way call recording including Bluetooth/Headphones" on Android 10+ (https://acr.app/)? - and I thought this limitation is because Accessibility services generally can't access the internal audio stream of the call - you just record the loudspeaker and microphone?

Only system apps that are signed by firmware key can record "real two-way" regular cellular phone calls on Android 10+ -they get all permissions they need?

And Android 8.1 for example does not need accessibility services to record a call (I've tried Android 8.1 Oreo and call recording works on non-rooted devices without accessibility services). So I thought you could also record calls without accessibility services using third party call recorder apps if the OS would not prevent it? (Even on Android 14)

So this is also because of the OS: https://nllapps.com/apps/acr/android9.htm - and Google would have been able to build higher Android versions that allow third party call recorder apps to have "real" call recording without root and without the need of accessibility services?

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It's provided by accessibility services without any significant limitations.

Accessibility services don't have a limit on what's considered a valid purpose at an OS level, only at a store policy level.

Do you mean that if I use a third party call recorder app that works using the accessibility services GrapheneOS should still make it possible to have "Real two-way call recording including Bluetooth/Headphones" (even if regular Android 10+ versions won't allow that; no root)?

[NLLAPPS]

Hi all just to chip in with some information. I am not sure how hard it would be or whether GrapheneOS would want to do it but, there is a hard permission check on VOICE_CALL audio source. App needs to be granted CAPTURE_AUDIO_OUTPUT permission

So, it is not possible to access it unless OS lifts that permission check or phone is rooted and granted by root manager