At Tue, 3 Aug 2010 13:15:28 -0700, pl bossart wrote:
Well, this is one of my looong-standing TODOs. Originally I wanted to implement a new API to get/set the channel-mapping, mainly for HDMI. But, I've been recently too busy for other tasks (I can spend little time for ALSA), thus it's pending forever.
You would only need an API to get the channel mapping. The HDMI sink will report its speaker configuration through a CEA code (section 7.4 of the spec), and if we parsed the EDID info we could present the relevant channel order to user-space apps.
But if the hardware is capable of channel-remapping (the intel hdmi code actually does even now), it's better as it works without any software-side channel swaps. Ditto for analog surrounds.
Of course, setting the channel-map is optional. The first step is to provide the API to get the map.
Takashi