IMX8MP on android 11 Bluetooth HFP SOC audio output problem

Wiser-Kuo — Thu, 15 Sep 2022 08:56:09 GMT

We use BCM4375 bluetooth (ap6275 chipset) on IMX8MP Android 11, and modified BT HAL to hardware/broadcom/libbt to make it work.

BT A2DP transmission works fine. (headphone without mic) , in/out BT audio transmit without problem.

BT SCO HFP : (headset with microphone)

While IMX8MP-AP6275 connected to a headset and use ZOOM app to make call with ZOOM software on PC ,

Audio output from headset has lot of noise (data transmit from PC) , it sounds like under-sampled and very low frequency sound.

My headset is not support WBS , so SCO rate is set at 8K , instead of 16k while running HFP.

I've tried to resample rates in tinyalsa_hal.cpp but it's not work.

( create_resampler with 8k in start_output_stream while AUDIO_DEVICE_OUT_ALL_SCO)

Is audo & BT HAL of iMX8mp support HFP while WBS disabled?

Is there any patches to make it works properly?

Attachment are modified patches for disable WBS and add SCO interface.

topic IMX8MP on android 11 Bluetooth HFP SOC audio output problem in i.MX Processors