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

[Thomas Martitz]

(Resending to the list as I sent it private accidentally)

Am 28.05.2013 09:23, schrieb David Henningsson:
 > On 05/28/2013 08:10 AM, Thomas Martitz wrote:
 >> Am 28. Mai 2013 04:54:52 schrieb Arun Raghavan
 >> <arun.raghavan at collabora.co.uk>:
 >>
 >>> >   - 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.)
 >>>
 >>> IMO, this is good for short-term porting effort, but not that great in
 >>> the longer term. The Android HAL is an abstraction on top of another
 >>> abstraction (UCM/XML config). To my mind, it makes more sense to use
 >>> UCM
 >>> here. Or if the UCM folks prefer the newer XML format, we could look at
 >>> that as well.
 >>
 >> I think the android Hal isn't stable at all so possibly you end up with
 >> code for each major android version or even each vendor / custom ROM
 >> (phone specific).
 >>
 >> Another question, is the Hal API defined somewhere or does it require
 >> reverse engineering?
 >
 > I think Android is quite fluid in the sense that things can indeed
 > vary between devices or versions of Android. OTOH, vendors are
 > unlikely to change this without a good reason as this would mean
 > additional coding efforts. Hence we would rely on de-facto standard,
 > which is this [1]. As you can see, source is available, so there is no
 > need to reverse engineer it.
 >
 > This is what I think; but I don't have the wide hardware experience
 > that would be good to have at this point.
 >

Custom ROM developers face always large problems during porting newer 
android versions to their devices, because vendors actually *do* touch 
the HAL *extensively*, and they obviously don't document the changes. 
They have a magnitude of reasons for this (not all of them are 
understandable) and it does make things difficult for anyone else.

Saying vendors are unlikely to change is jumping into conclusions to 
early. They do anything needed to provide more/better features than the 
competitors.

Best regards.