[alsa-devel] plughw and hw

[hong zhang]

Takashi,

Last e-mail, you mention do not use plughw but hw. I compare both of them. And wonder which way is correct to capture multiple pins.

my HDMI has 4 pins

1. HW failed with "-c 8"
# arecord -f dat -d 5 -D hw:0,1  -c 8 05-12-new-hw-3pins.wav
Recording WAVE '05-12-new-hw-3pins.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Channels 8
arecord: set_params:1059: Channels count non available

2. HW collect data for all 4 pins without "-c 8"

3. plughw with "-c 8" but only first pin has data inside 2 channels. The rest pins collect 0 data.

4. plughw collects data for all pins without "-c 8"

why "-c 8" would not work right?

Thanks.

---henry