2012-8-9 下午8:49 於 "Clemens Ladisch" clemens@ladisch.de 寫道：
arun kumar wrote:
From the last couple of days, I have been trying to understand the Linux Alsa Subsystem.I have read the Alsa Driver API and Application API's.
But I
could not understand the concept of PCM substreams,
A PCM stream has one or more substreams. Multiple substreams are used
when
the hardware can mix them together for one output. This was used in old wavetable sound cards; nowadays, you almost always have one substream.
There are some hda controllers support multi-stream capture and some hda codecs have two or more adc which allow two applications using different mic
List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog] Subdevices: 3/3 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2