[pulseaudio-discuss] Pulseaudio A2dp - Audio data loss and stutter

[Pierre-Louis Bossart]

> > We are trying to get a2dp work using pulse audio 1.0 on arm 11 based
> > evaluation board. The porting of  pulseaudio 1.0 to an ARM 11 board
> > did not take any additional effort at all unlike the previous
> > versions. The module loopback for hfp works very well. But when we
> try
> > a2dp streaming, we get continuous stutter in the audio. we are using
> > 'trivial' resampler, as with others there is no audio at all.
> 
> Someone else might be able to answer about why module-loopback does
> this, but what's the CPU utilisation like? To make sure that doesn't
> play a part in all this, do ensure that the SBC code bundled with PA is
> built with NEON, or if your CPU doesn't have it, ARMv6 optimisations.

Does the hfp routing use a PCM/ALSA output (HCI bypass)? If yes, I would
think the latency estimation reported by the A2DP sink is not correct, and
the loopback fails to estimate the right sampling frequency. There are some
messages in your log along these lines.
It's been bugging me for some time, the frequency estimation based on the
latency snapshot seems broken with A2DP or RTP outputs. We would need some
low-pass filter I guess.
-Pierre