At Wed, 05 Sep 2012 10:32:24 +0200, David Henningsson wrote:
On 09/04/2012 05:47 PM, Takashi Iwai wrote:
The phase inverted channel has this bit: #define SNDRV_CHMAP_PHASE_INVERSE (0x01 << 16)
Hmm. On second thought, as mics are plugged in and unplugged during recording, the channel map will change. (E g, changing a digital mic with phase inverse, to a stereo line in)
Will we also need a notify callback in alsa-lib to know changes in the channel map?
It's possible to implement (just a call of snd_ctl_notify()), but I don't know whether this is expected by the user-space.
Obviously the configuration isn't expected to be changed dynamically without hw_params change. So basically ditto for the channel map.
I guess the phase inverse thing makes sense once after we implement separate PCM streams for d-mic. Other than that, dynamic switching the channel map doesn't sound like a helpful scenario.
Takashi