ALSA: Setting FIFO type as the slave for dsnoop
GitHub issues - opened
github at alsa-project.org
Wed Aug 10 17:42:20 CEST 2022
alsa-project/alsa-lib issue #257 was opened from cnkoder:
**Problem**
I am facing problems in using "dsnoop" to share/divide the audio stream into two. When dsnoop plugins' slave is set to be a FIFO it throws an error.
executed:
sudo arecord -D default -f cd defRecording.wav -c 1 -r 32000
error:
ALSA lib pcm_direct.c:1809:(_snd_pcm_direct_get_slave_ipc_offset) Invalid type 'fifo' for slave PCM
arecord: main:828: audio open error: Invalid argument
This is the current asound.conf settings
asound.conf
<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-html -->
pcm.!default {
type asym
playback.pcm "playback"
capture.pcm "capture1 "
}
pcm.playback {
type plug
slave.pcm "eci"
}
# Stream Output 1: Final
pcm.capture1 {
type plug
slave.pcm "array"
}
# Stream Output 2: Final
pcm.capture2 {
type plug
slave.pcm "array"
}
# Used to share the record device
pcm.array {
type dsnoop
slave {
pcm "eco"
channels 1
}
ipc_key 666666
}
# Writes audio coming from any sort of player to ec.input, this is read by the echo
# cancellation software.
pcm.eci {
type plug
slave {
format S16_LE
rate 32000
channels 1
pcm {
type file
slave.pcm null
file "/tmp/ec.input"
format "raw"
}
}
}
# Read FIFO output which contains echo cancelled audio
pcm.eco {
type plug
slave.pcm {
type fifo
infile "/tmp/ec.output"
rate 32000
format S16_LE
channels 1
}
#ipc_key 666666
}
<!-- end snippet -->
Note:
eco is used to read the FIFO file which contains the echo canceled audio coming in from cancellation software. This software's input is hw:0 and records audio directly from the microphone, and then processes and passes this over to ec.output
Dsnoop works well when the slave.pcm is a hardware device but as soon as I point to something else it fails.
Is there a workaround or any other solution to tackle this problem?
Issue URL : https://github.com/alsa-project/alsa-lib/issues/257
Repository URL: https://github.com/alsa-project/alsa-lib
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