GUADEC: porting GNOME to Android

Posted Aug 18, 2012 18:05 UTC (Sat) by Cyberax (✭ supporter ✭, #52523)
In reply to: GUADEC: porting GNOME to Android by alankila
Parent article: GUADEC: porting GNOME to Android

> For security reasons, random DSP plugins can't be done on Android either,
Nope. DSP is often done in _hardware_ on Android (for instance, on Galaxy S phones) and sometimes sound stream doesn't even touch the CPU. So that's the reason for non-dynamic AF plugins.

GUADEC: porting GNOME to Android

Posted Aug 18, 2012 21:16 UTC (Sat) by alankila (guest, #47141) [Link]

Oh, some DSP probably is. The sort of thing I have in mind is not. I am not aware of any mediaplayer-based sound streams that would not touch the CPU, although as far as I know phone conversations occur without the main CPU being able to interface with either of those streams.

In any case, Android vendors can provide vendor-specific implementations of AudioEffects, and I suppose it might be possible to hardware-accelerate more of the AudioFlinger API. There's a lot of maybes to this, because last time I looked there was but one digital stream that everything got mixed to, and whatever "DSP" was involved was concerned entirely with the mechanics of generating analog audio from that single PCM data.

So there's multiple kinds of things called "DSP" here. The fact that custom DSP plugins are not possible is obvious given that they must be loaded to a root-owned process implemented in C which must not crash and must be as realtime as possible. So random code, or offloadng processing by some IPC approach is probably out.