[pulseaudio-discuss] How to create a virtual microphone with source set as default monitor device?

[guest271314]

> Point Espeak's output to the "Feed Espeak" sink, and point your
recording application at the "ESpeak output virtual mic".

What is meant by "point" here? How to do that?

Were you able to successfully carry out the procedure yourself?

What would be ideal is to be able to control pavucontrol -t 2 GTK or
Qt page from HTML.

Where in pavucontrol source code is Recording tab implemented?

On Tue, Sep 15, 2020 at 2:34 PM Sean Greenslade <sean at seangreenslade.com> wrote:
>
> On Sun, Sep 13, 2020 at 05:18:23PM +0000, guest271314 wrote:
> > This project started attempting to capture the output of
> > window.speechSynthesis.speak().
> >
> > Consider https://stackoverflow.com/a/43553706.
> >
> > If run $ pacmd list-sink-inputs will get
> >
> >     index: 219
> >     driver: <protocol-native.c>
> >     flags:
> >     state: RUNNING
> >     sink: 4 <alsa_output.pci-0000_00_14.2.analog-stereo>
> >     volume: mono: 64460 /  98% / -0.43 dB
> >             balance 0.00
> >     muted: no
> >     current latency: 0.00 ms
> >     requested latency: 0.59 ms
> >     sample spec: s16le 1ch 22050Hz
> >     channel map: mono
> >                  Mono
> >     resample method: speex-float-1
> >     module: 14
> >     client: 192 <speech-dispatcher-espeak-ng>
> >     properties:
> >         media.name = "playback"
> >         application.name = "speech-dispatcher-espeak-ng"
> >         native-protocol.peer = "UNIX socket client"
> >         native-protocol.version = "33"
> >         application.process.id = "45464"
> >         application.process.user = "ubuntu-studio"
> >         application.process.host = "ubuntu-studio"
> >         application.process.binary = "sd_espeak-ng"
> >         application.language = "C"
> >         window.x11.display = ":0.0"
> >         application.process.machine_id = "<id>"
> >         application.process.session_id = "<id>"
> >         module-stream-restore.id =
> > "sink-input-by-application-name:speech-dispatcher-espeak-ng"
> >
> > $ pacmd list-sources
> >
> > 2 source(s) available.
> >   * index: 4
> >     name: <alsa_input.usb-046d_0804_0B17FC60-02.mono-fallback>
> >     driver: <module-alsa-card.c>
> >     flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY
> > DYNAMIC_LATENCY
> >     state: RUNNING
> >     suspend cause: (none)
> >     priority: 9040
> >     volume: mono: 0 /   0% / -inf dB
> >             balance 0.00
> >     base volume: 20724 /  32% / -30.00 dB
> >     volume steps: 65537
> >     muted: yes
> >     current latency: 4.60 ms
> >     max rewind: 0 KiB
> >     sample spec: s16le 1ch 48000Hz
> >     channel map: mono
> >                  Mono
> >     used by: 1
> >     linked by: 1
> >     configured latency: 40.00 ms; range is 0.50 .. 2000.00 ms
> >     card: 1 <alsa_card.usb-046d_0804_0B17FC60-02>
> >     module: 8
> >     properties:
> >         alsa.resolution_bits = "16"
> >         device.api = "alsa"
> >         device.class = "sound"
> >         alsa.class = "generic"
> >         alsa.subclass = "generic-mix"
> >         alsa.name = "USB Audio"
> >         alsa.id = "USB Audio"
> >         alsa.subdevice = "0"
> >         alsa.subdevice_name = "subdevice #0"
> >         alsa.device = "0"
> >         alsa.card = "1"
> >         alsa.card_name = "USB Device 0x46d:0x804"
> >         alsa.long_card_name = "USB Device 0x46d:0x804 at
> > usb-0000:00:12.0-1.4, high speed"
> >         alsa.driver_name = "snd_usb_audio"
> >         device.bus_path = "pci-0000:00:12.0-usb-0:1.4:1.2"
> >         sysfs.path =
> > "/devices/pci0000:00/0000:00:12.0/usb1/1-1/1-1.4/1-1.4:1.2/sound/card1"
> >         udev.id = "usb-046d_0804_0B17FC60-02"
> >         device.bus = "usb"
> >         device.vendor.id = "046d"
> >         device.vendor.name = "<vendor>"
> >         device.product.id = "0804"
> >         device.product.name = "<name>"
> >         device.serial = "046d_0804_0B17FC60"
> >         device.form_factor = "webcam"
> >         device.string = "hw:1"
> >         device.buffering.buffer_size = "192000"
> >         device.buffering.fragment_size = "96000"
> >         device.access_mode = "mmap+timer"
> >         device.profile.name = "mono-fallback"
> >         device.profile.description = "Mono"
> >         device.description = "<description>"
> >         module-udev-detect.discovered = "1"
> >         device.icon_name = "camera-web-usb"
> >     ports:
> >         analog-input-mic: Microphone (priority 8700, latency offset 0
> > usec, available: unknown)
> >             properties:
> >                 device.icon_name = "audio-input-microphone"
> >     active port: <analog-input-mic>
> >
> > One part of what am trying to do is create a virtual microphone that
> > takes input from speech-dispatcher-espeak-ng persistently or route
> > output from speech-dispatcher-espeak-ng to the microphone, so that
> > when capture the microphone the output will be from speech-dispatcher.
> > How to achieve that?
>
> $ pacmd load-module module-null-sink sink_name=feed_espeak_to_me
> $ pacmd update-sink-proplist feed_espeak_to_me device.description="\"Feed Espeak\""
> $ pacmd update-source-proplist virtual_mic_espeak_output device.description="\"ESpeak output virtual mic\""
>
> Point Espeak's output to the "Feed Espeak" sink, and point your
> recording application at the "ESpeak output virtual mic".
>
> --Sean
>
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