2012-8-18 下午12:09 於 "Tanu Kaskinen" tanuk@iki.fi 寫道：
On Sat, 2012-08-18 at 09:26 +0800, Raymond Yau wrote:
2012-8-17 下午10:51 於 "Tanu Kaskinen" tanu.kaskinen@digia.com 寫道：
Ping?
If card specific pcm definitions are not possible, would it be acceptable to have a generic "front_left:CARD" or "first_channel:CARD" pcm, which would transform "front:CARD" or "hw:CARD" into a mono
device?
As pulseaudio server use SND_PCM_NO_AUTO_CHANNEL which diable channel conversion, this left channel device only work with other alsa
applications
except pulseaudio when your sound card does not support mono.
So are you suggesting that Alsa doesn't need any changes, because all other applications allow automatic channel conversion, and therefore this is a PulseAudio specific problem and should be fixed in PulseAudio?
strictly speaking your mic is not a true stereo mic and the channel map is [left, null] instead of the normal map [left,right] of line-in or stereo mic
the channel map for those stereo mic which have out of phase left and right channel is either [left,-left] or [-right,right]
some stereo mic may has [null,right]