[pulseaudio-discuss] Problems with Pulseaudio and Bluetooth Headset

[James Bottomley]

I suspect this is some type of resampler problem rather than an actual
connection problem.  The headset is a GN6210H (which is a phone headset,
so mono earpiece and mono mic).  The only other oddity is that apart
from having only one channel, its sample rate is 8000Hz.

I have it all correctly plumbed into alsa using bluez and if I just use
alsa, I can send sound to it with mplayer using

mplayer -ao alsa:device=headset

Since mplayer sees the device directly, it sends the sound stream as

AO: [alsa] 800Hz 1ch s16le (2 bytes per sample)

And everything sounds fine.

When I plug it into pulseaudio with

pactl load-module module-alsa-sink device=headset

It correctly picks up the sample rate and channels.  However, trying to
switch an application to it results in dramatic speed increases and the
output being chopped to pieces.  If I set up pulseaudio only to have
this device and nothing else, mplayer plays the sound file at at least
2x the usual speed.

Since the output has this:

AO: [pulse] 44100Hz 2ch s16le (2 bytes per sample)

I suspect the problem is somewhere in the pulseaudio resampling down
from 2 channels at 44100Hz to a single channel at 8000Hz.  I've tried
forcing different resampling methods with slightly different sounding
results but still playing at at least 2x the speed.

James