1448784 - Re-add get preferred layout method

Status: NEW

(Core :: Audio/Video: cubeb, enhancement, P2)

Description

[Jean-Yves Avenard [:jya]]

In :
Bug 1432779 - P4. Remove the concept of preferred layout.

The method to retrieve the preferred layout was removed. However I can see some use for it in the case where the AudioSink will perform conversion in order to keep the same format as originally input.

cubeb has no method to change the content type on the fly.

So the AudioSink instead always convert the format so that it always match the initialized mode.
Like say we start playing a 5.1 audio file, and then the input changed to stereo.

The AudioSink will now convert the stereo to a 5.1.
If the default output in stereo only, when doing the conversion we can only assign the left and right channels to the front.

However, if the default layout is 5.1, we could instead do a proper 5.1 upmix mixing left and right into center etc...