- The Audio preferences dialog: set audio device parameters. The dialog shows one tab for output and another tab for input devices. Detailed in sections 1 and 2.
- The Audio selection dialog: each channel plugin having audio output or input can show this dialog to select which device to use to direct output or input streams. This dialog opens by right clicking on a button that depends on the plugin (see plugin documentation). Detailed in section 3.
This dialog lets you set preferences for the audio output devices attached to the system. These devices may refer to actual physical devices or be virtual devices defined with Pulseaudio (Linux).
Each device is represented by a row in the list. Move the cursor with the mouse or the arrow keys to select the device you want to configure.
-`S`: for system default device. This is the device that is defined as system default. You may configure it directly or via the ` System default device` entry. <br/>☞ Note that (at least in Linux) you may affect different parameters to one or the other.
-`D`: the device is unregistered so if you associate an output stream to it it will be registered with default values. Default values are:
This is the device name defined in the system. In Linux when you define virtual devices (null sinks) with Pulseaudio this is the name you have given when defining the device.
<h3>1.3 System default device</h3>
The device that is configured as system default is marked with a grey background behind its name
<h3>1.4 Selected device</h3>
The device currently selected is marked in the selection color (orange). The parameters below are updated with its corresponding values
This is the SDP string representation of the stream sent via UDP (RTP). In SDP files it is used on the `a=rtpmap`line (See 1.14). It can be used to check the effect of settings 1.5, 1.8 and 1.9.
You may read the RTP stream using a SDP file (extension `.sdp`) that can be read with any program supporting SDP files (VLC, MX player, ffmpeg, ...). For a mono 48000 S/s stream at address `192.168.0.34:9998 and L16 codec the contents of the file would be as follows:
☞ Note that on Android clients VLC has trouble working with the RTP stream (choppy audio, hanging unexpectedly...) therefore [MX player](https://play.google.com/store/apps/details?id=com.mxtech.videoplayer.ad&hl=en) is recommended.
☞ With PCMA and PCMU and more recently G722 codecs it is possible to listen to the RTP stream directly in the browser using a [Janus WebRTC server](https://janus.conf.meetecho.com/). Please refer to the Wiki page "Networking audio" for detailed instructions.
Click on the open file icon to open a file selection dialog that lets you specify the location and name of the output files.
Each recording is written in a new file with the starting timestamp before the `.wav` extension in `yyyy-MM-ddTHH_mm_ss_zzz` format. It keeps the first dot limited groups of the filename before the `.wav` extension if there are two such groups or before the two last groups if there are more than two groups. Examples:
- Given file name: `test.wav` then a recording file will be like: `test.2020-08-05T21_39_07_974.wav`
- Given file name: `test.2020-08-05T20_36_15_974.wav` then a recording file will be like (with timestamp updated): `test.2020-08-05T21_41_21_173.wav`
- Given file name: `test.first.wav` then a recording file will be like: `test.2020-08-05T22_00_07_974.wav`
If a filename is given without `.wav` extension then the `.wav` extension is appended automatically before the above algorithm is applied. If a filename is given with an extension different of `.wav` then the extension is replaced by `.wav` automatically before the above algorithm is applied.
The file path currently being written (or last closed) appears at the right of the button.
<h3>1.17 Record silence time</h3>
This is the time in seconds (between 0.1 and 10.0) of silence (null samples) before recording stops. When non null samples come again this will start a new recording. Set the value to 0 to record continuously.
<h3>1.18 Cleanup registrations not in the list</h3>
Use this button to keep only the visible devices in the devices registrations. The devices registrations with custom parameters are kept in the preferences using the device names. This button makes some tidying up when devices are permanently removed.
Use this button to remove the device from the devices registrations returning it to the unregistered state. Therefore when associated to an output stream or selected it will initially take default values and appear with the `D` indicator in the list.
Use this button to dismiss your changes and close dialog.
<h2>2. Audio input preferences</h2>
This dialog lets you set preferences for the audio input devices attached to the system. These devices may refer to actual physical devices or be virtual devices defined with Pulseaudio (Linux).
Each device is represented by a row in the list. Move the cursor with the mouse or the arrow keys to select the device you want to configure.
-`S`: for system default device. This is the device that is defined as system default. You may configure it directly or via the ` System default device` entry. <br/>☞ Note that (at least in Linux) you may affect different parameters to one or the other.
-`D`: the device is unregistered so if you associate an input stream to it it will be registered with default values. Default values are:
This is the device name defined in the system. In Linux when you define virtual devices (null sinks) with Pulseaudio an input device is automatically created with the `.monitor` extension.
<h3>2.3 System default device</h3>
The device that is configured as system default is marked with a grey background behind its name
<h3>2.4 Selected device</h3>
The device currently selected is marked in the selection color (orange). The parameters below are updated with its corresponding values
This factor in the range [0.01 .. 1.00] is applied to the input before modulation.
<h3>2.7 Reset values to defaults</h3>
By pushing this button the values are reset to the defaults (see 2.1 for actual default values)
<h3>2.8 Cleanup registrations not in the list</h3>
Use this button to keep only the visible devices in the devices registrations. The devices registrations with custom parameters are kept in the preferences using the device names. This button makes some tidying up when devices are permanently removed.
Use this button to remove the device from the devices registrations returning it to the unregistered state. Therefore when associated to an output stream or selected it will initially take default values and appear with the `D` indicator in the list.
Use this button to confirm your changes and close dialog. Note that you can change parameters of only one device at a time.
<h3>2.11 Cancel button</h3>
Use this button to dismiss your changes and close dialog.
<h2>3 Audio device selection</h2>
In plugins having audio input or output this dialog can be opened to select the input or output device for the audio stream. The exact button that opens the dialog by right clicking on it depends on the plugin. Generally this will be the audio in selection (microphone icon) for input plugins and the audio mute (loudspeaker icon) for output plugins. You may check the plugin documentation for confirmation.
The dialog for input or output is similar. The screenshot below is taken from an output selection.
-`S`: for system default device. This is the device that is defined as system default. You may configure it directly or via the ` System default device` entry. <br/>☞ Note that (at least in Linux) you may affect different parameters to one or the other.
-`D`: the device is unregistered so if you associate an input stream to it it will be registered with default values. Default values depend on the input or output nature and are listed in the 2.1 and 1.1 sections respectively.
This is the device sample rate in samples per seconds. Please note that the baseband sample rate should not be lower than this rate for correct audio operation of AM, NFM and SSB plugins.
☞ Using devices with sample rates lower than 48000 S/s may allow baseband sample rates lower than 48 kS/s with AM, NFM and SSB plugins. This is not true for wideband plugins (BFM, WFM) that use baseband rates in accordance with the RF bandwidth required nor for DSD plugin that uses internally a fixed channel rate of 48 kS/s to be able to decode symbols properly.
☞ The DSD demodulator plugin accepts only audio sample rates of 48000 or 8000 S/s to process audio properly.
<h3>3.4 System default device</h3>
The device that is configured as system default is marked with a grey background behind its name
<h3>3.5 Selected device</h3>
The device currently selected is marked in the selection color (orange). Use the mouse or the arrow keys to change selection.
<h3>3.6 OK button</h3>
Use this button to confirm your selection and close dialog.
<h3>3.7 Cancel button</h3>
Use this button to dismiss your selection and close dialog.
