HFP choppy audio from Windows

[tpbedford]

When running the pipeline_hfp_stream_example from ESP-ADF I get very choppy & corrupted audio playback from my PC to my LyraT board. Recorded audio (from LyraT mic back to PC) is perfect. Weirdly the ESP32 works perfectly when paying back through my phone. It also happens on a second laptop:

• ESP32 (LyraT) and laptop 1: playback from laptop is buzzy but recorded audio is perfect
• ESP32 (LyraT) and laptop 2: playback from laptop is buzzy but recorded audio is perfect
• headset and laptop 1: playback and recorded audio is perfect
• ESP32 (LyraT) and phone: playback and recorded audio is perfect

I'm looking for some ideas on where to look for problems. I feel it's a Bluetooth problem as my Microsoft Bluetooth mouse becomes very laggy during HFP audio playback (whilst my touchpad remains responsive), as if there's an excess of BT radio communications happening. The problem does not occur between my PC and other HFP headsets.

It happens when using wideband or normal audio (16kHz vs 8kHz) - there's no change at all between these two, nor any change when selecting 240MHz CPU speed or the default 160MHz. I can also only stop/start the audio a couple of times before the example crashes with SCO errors & timeouts:

W (1620954) BT_BTM: SCO xmit Q overflow, pkt dropped
W (1620954) BT_BTM: stat 10

The audio playback is mostly just a loud harsh buzz, with my played audio being faintly audible behind the buzz.

It happens on both my custom ESP32-WROOM board and also the stock LyraT board. I also have a LyraTD which I haven't tested yet. I'm using ESP-IDF 4.3 (though IDF 4.4 doesn't seem to have significant changes to HFP code) and ESP-ADF master branch from mid-December as the official ADF 2.3 didn't have support for IDF 4.3.

[kturanmak]

Hi, Did you solve the problem?