When building a radio app, it is recommended to use the
HwAudioSource as it will handle both creating the patch as well as
a media session to handle media key events. Multiple audio sources can be created
for the same source & audio attributes. So it is possible to have one for regular
radio usage as well as a second one for traffic announcements.
If recording the FM_TUNER, in Android 11 the permission for doing so
has been changed to android.permission.CAPTURE_AUDIO_OUTPUT. It's
no longer going through OP_RECORD_AUDIO permission check, which is
applicable to microphones only. This shouldn't have an impact on apps as
FM_TUNER already required SYSTEM_API permission to access.
See Implementing Radio for more details on building a radio app.