HI
I'd like to make a software echo in lowest possible latency
(what I say to the mic should be heard from the speaker).
Besides it has to be mixed with VoIP telephony application that
is used to make the call.
Internal usb mixer hardware doesn't support this so I'd like to
specify it somehow in .asloundrc - anybody can help me with
some example?
Local echo simulates behaviour of analog telephone
and will much improve quality of VoIP (if can achieves low latency
of 0.1 second or faster).
I need that for an USB phone (yealink p1k) on debian linux with
kernel 2.6.25 (alsa from kernel). usb phone device contains usb alsa
compatible 8khz pcm and mic
This device looks like
aplay -l
card 1: default [VOIP USB Phone ], device 0: USB Audio [USB Audio]
Subdevices: 0/1
Subdevice #0: subdevice #0
arecord -l
card 1: default [VOIP USB Phone ], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
amixer -c 1
Simple mixer control 'PCM',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 65534
Mono: Playback 65534 [100%] [-127.99dB] [on]
Simple mixer control 'PCM',1
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 65534
Mono: Playback 65534 [100%] [-127.99dB] [on]
Simple mixer control 'Mic',0
Capabilities: cvolume cswitch cswitch-joined
Capture channels: Mono
Limits: Capture 0 - 65534
Mono: Capture 65534 [100%] [-127.99dB] [on]
Simple mixer control 'Mic',1
Capabilities: cvolume cswitch cswitch-joined
Capture channels: Mono
Limits: Capture 0 - 65534
Mono: Capture 65534 [100%] [-127.99dB] [on]
In the mixer PCM,0 and PCM,1 are the same
(any pcm,0 or pcm,1 controls volume of the speaker)
PCM,0 and PCM,1 can have different volumes but the one that I
changed last is accepted to the speaker
and Mic,0 and Mic,1 are the same like above but for the mic
currently I'm using a simplest .asoundrc that I found
by experimet it provides lowest latency
(however no echo with this of course)
ctl.!default {
type hw
card 1
}
pcm.!default {
type hw
card 1
}
Best regards, Davor
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