[alsa-devel] [RFC] Channel mapping API

Mark Brown broonie at opensource.wolfsonmicro.com
Tue Aug 21 16:06:48 CEST 2012

On Tue, Aug 21, 2012 at 04:00:37PM +0200, David Henningsson wrote:
> On 08/21/2012 01:37 PM, Clemens Ladisch wrote:

> >This doesn't handle devices with simply numbered outputs (such as many
> >ICE1712-based devices), or cases where one PCM channel can be routed to
> >multiple outputs.  However, those devices typically have their own mixer
> >applets, and generic applications aren't interested in configuring them.

> As for routing more than one channel in the map from the same PCM,
> that seems a bit more complex. Maybe one could do a bitmap of
> channels instead of just one channel (with say, 32 room channel
> positions and 32 just numbered positions, that would be 64 bits).
> But how common is that anyway?

It's very common on the embedded side to use pure numbered stuff (or at
least to assign semantics dynamically at runtime which I suspect boils
down to the same thing here).

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