[pulseaudio-discuss] PulseAudio on Android kernel, for Ubuntu phone

[David Henningsson]

On 05/27/2013 08:57 PM, David Henningsson wrote:
> Well, as some of you already know, Canonical is currently working on an
> Ubuntu phone product. Part of that is a well working audio stack.
>
> In short, we're trying to build something where we can run as much of
> standard Ubuntu as possible and as little of Android as possible,
> without having to rewrite a lot of hardware specific stuff. That's at
> least how I understand it. :-)
>
> So, my plan is to start building something really soon. My draft plan
> looks like:
>
>   - For PCM streaming, I'll try to use native ALSA, i e, PulseAudio,
> alsa-lib, kernel, just as on the desktop. This is for best performance,
> and also because it's the nicest thing to do for non-PA sound servers
> and applications (e g JACK).
>
>   - For setting up the mixer, I'll try to talk to the Android HAL layer.
> Mixer controls vary a lot between hardware, so making a bridge to
> Android here would likely save us work in the long run. (This is the
> most uncertain part.)

After some deeper investigation, it's high probability that this won't 
work, at least not on all devices. The reason for this is that some of 
the HAL implementations will mute everything as long as there is no 
streaming in progress (and no phone call going on). So, since we don't 
use the HAL for PCM streaming, using it for just the mixer won't work - 
the HAL will just assume that there is no stream going on and mute 
everything.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic