diff options
| author | St33v <github@f3rr3t.com> | 2022-01-26 23:10:32 +1100 |
|---|---|---|
| committer | St33v <github@f3rr3t.com> | 2022-01-26 23:10:32 +1100 |
| commit | b081209514523095ccb05cc5b3afdbb01d48751c (patch) | |
| tree | 06c1719c3d8097c6a8d30b5ee423c9c76bb5d8d1 /speakerSqeaker.txt | |
| parent | 9cbc7826870640648f0c1e20cd2210c7c4d0f47b (diff) | |
rename
Diffstat (limited to 'speakerSqeaker.txt')
| -rw-r--r-- | speakerSqeaker.txt | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/speakerSqeaker.txt b/speakerSqeaker.txt new file mode 100644 index 0000000..d78c40a --- /dev/null +++ b/speakerSqeaker.txt @@ -0,0 +1,65 @@ +#! /bin/bash +# Workaround for stupd 'powersave' 'feature' of Creative Speakers +# +# SJP 11 Dec 2021 +# +# This is just a stub for now + +# Which device is the audio output going to? + +# st33v@cr4y:~$ grep RUNNING /proc/asound/card*/pcm*/sub*/status +# /proc/asound/card2/pcm0p/sub0/status:state: RUNNING + +# That is fine, but the status remains as 'RUNNING' even after the speakers have turned themselves off... +# So I'm going down the track of periodically sending a 'sound' to a loopback device +# sudo modprobe snd-aloop +# Now aply -l shows a new 'card' called Loopback. + + +record one second of default stream: + +$ rec -d -n trim 0 1 stat + + rec sox in record mode + -d default input + -n direct output to /dev/null + trim 0 1 duration 1 second + stat + +Output: + +Input File : 'default' (pulseaudio) +Channels : 2 +Sample Rate : 48000 +Precision : 16-bit +Sample Encoding: 16-bit Signed Integer PCM + +In:0.00% 00:00:01.02 [00:00:00.00] Out:48.0k [ | ] Clip:0 +Samples read: 96000 +Length (seconds): 1.000000 +Scaled by: 2147483647.0 +Maximum amplitude: 0.000000 +Minimum amplitude: 0.000000 +Midline amplitude: 0.000000 +Mean norm: 0.000000 +Mean amplitude: 0.000000 +RMS amplitude: 0.000000 +Maximum delta: 0.000000 +Minimum delta: 0.000000 +Mean delta: 0.000000 +RMS delta: 0.000000 +Rough frequency: -2147483648 +Done. + +So if Max amplitude = 0 then we have silence! + +to generate a tone that is not audible: +play -n synth 1 sine 40 fade .2 0 + + play sox alias + -n dummy input file + synth synthesise a sound + sine sine wave [the default, so not strictly necessary] + 40 Hz + fade fade in from zero volume to max volume over 200 msec. + '0' says fade out at end over same period. |