Audio with Bluetooth

[Abelardo21]

hola buen dia, escribo en este medio porque tengo ciertos detalles respecto al bluetooth. Al realizar llamadas con bluetooth la calidad del audio disminuye considerablemente (he intentado con varios auriculares y celulares) solo con un samsung A52 me ha funcionado bien, es de menor calidad pero aun es entendible el audio, sin embargo en la gran mayoria de otros casos es inestable el audio y la llamada en general.

Hello, good day. I am writing here because I have certain details regarding bluetooth. When making calls with bluetooth, the audio quality decreases considerably (I have tried with several headphones and cell phones) only with a Samsung A52 it has worked well for me, it is of lower quality but the audio is still understandable, however in the vast majority of other cases the audio and the call in general are unstable.

private fun initAudioManager() {
    audioManager = getSystemService(Context.AUDIO_SERVICE) as AudioManager
    resetSco()
    audioManager.startBluetoothSco()
}

private fun resetSco() {
    audioManager.mode = AudioManager.MODE_IN_COMMUNICATION
    val audioTrack = AudioTrack(
        AudioManager.STREAM_VOICE_CALL,
        8000, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT,
        16,
        MODE_STREAM
    )
    
    audioTrack.play()

    audioManager.stopBluetoothSco()
    audioManager.isBluetoothScoOn = false
    audioManager.isSpeakerphoneOn = false
    audioManager.isWiredHeadsetOn = false

[Roland_Ian]

Hi,

Thanks for the information! Glad to see your are testing with Bluetooth!

If you look at the sinch-rtc-sample-push sample with the SDK, the AudioPlayer sample rate is set to 16000, is there a reason here you are using 8000 ?

If you would like individual calls analysed for call quality and perceived instability, please provide a call-id via a ticket in our support portal -> messaging.  (https://tickets.sinch.com/plugins/servlet/desk/portal/31)

[Abelardo21]

Thank you, I already set the parameter to 16000 but in some tests (samsung galaxy a52) it is more stable and in others (Poco X3) it is not possible to use bluetooth, it transmits the audio through the phone speaker with interference

[Roland_Ian]

Hi

I think we have our answer there, seems the bluetooth implementations and capacity varies greatly between different handset vendors.  

Android have a new LC3 codec for BLE audio with API 33, however currently this has not been evaluated in the SDK samples, as it is only for the latest API version and for BLE capable handsets. https://developer.android.com/guide/topics/connectivity/ble-audio/overview.

I invite you to open a ticket if you want an individual call-id looked at in any case.