SoundCard | A Pure-Python Real-Time Audio Library

I'm a not-so-knowledgeable person in the Linux world trying to understand an audio problem I have in a project. In short, I'm trying to get an audio output through a Java library called Minim (ddf.minim). I can get an output by listening to an input and enabling "monitoring." Monitoring echoes the input to an output. I cannot however get a working output line independent of this feature.

This application is running on a BeagleBone Black with Debian Buster. This is an ARM microcontroller. My Java application starts up with the system as a systemd service as the root user. It runs in headless mode but with a virtual frame buffer (xvfb) because it's a Processing application. I have a USB hub connected to the BeagleBone, which hosts a USB-to-AUX adapter. The AUX side splits into the pink/green input/output cables. I have a mic connected to the pink end and earbuds into the green end.

When Minim's getLineIn() is used to get an input, no errors are seen. Enabling monitoring doesn't generate errors either. Using getLineOut() will show errors that look like this:

I am trying to build a simple app that plays audio files in the asset folder.

I am using a Stream Builder to return a card for each sound to show pause and play icons. but strangely my app throws a null error when I add more than 10 sounds in the sound model.

here is my sound model class :

Trying to setup android-x86_64 inside vmware-workstation16, ALSA audio device as default/unprivileged user doesn't seem to be accessible. Trying to manually call alsa_amixer set PCM 100%/alsa_aplay /mnt/sdcard/Download/test.wav as non-root gives permission denied, all of this works fine as root.

Since android is based on linux I was trying around to somehow manually give default user access to specific ALSA device. I looked around manually adjusting /etc/group (which doesn't seem to be valid config file for android), giving read/write access to audio devices inside /dev/, but I couldn't identify which device that would be. Tried to manually alsa_ctl init 0 (but device is already correctly initialized on root's side) with no difference.

Output of commands as root user:

Background:

I have an old Seagate BlackArmor NAS 110 that I'm trying to install Debian on by following the instructions here: https://github.com/hn/seagate-blackarmor-nas.

I have a couple of USB to TTL serial adapters (one FTDI chipset and the other Prolific) that I've tried and have run into the same issue with both. I have made the connection to the serial port on the board of the NAS using a multimeter to make sure I've gotten the pinout correct.

Problem:

I'm not able to stop the autoboot process by pressing keys and any point during the boot process. The device also does not seem to respond to any keystrokes although they are echoed back.

What I've Tried So Far:

• Using USB to TTL serial adapters with two different chipsets
• Using the adapters on two different computers (MacBook Pro and a ThinkPad)
• Using different operating systems (MacOS, Windows 10, Ubuntu 20.04)
• Using different terminal programs (Screen, Minicom, Putty)
• Turned off hardware and software flow control
• Tested output of adapters by shorting RX and TX pins and seeing keystrokes echoed back
• Commands seem to be sent to device as when I type I see my commands echoed back (not sure if this is supposed to happen)

I've been at this for a few days and can't figure it out. I've also recorded my screen while experiencing the issue: https://streamable.com/xl43br. Can anyone see where I'm going wrong?

Terminal output while experiencing the problem:

I 've been trying to create a "communication wire" from my Raspberry Pi microphone (usb headsets) to my soundcard in order for the script to send whatever I say at microphone to my speakers through a pipeline.

Problem:

When i run the script below, the mic works and sends voice at my speakers for a couple of seconds. After that it stops repeating what i am saying.

The code i have is shown below:

I am using the soundcard library to record my microphone input, it records in a NumPy array and I want to grab that audio and save it as an mp3 file.

Code:

I am beginner in flutter. I want to create a 8x2 gridview with button(custom button widget).But Items in GridView lost its state when it when they are out of the viewport.I also tried SilverGrid.There also the same proplem.Here is my code snippet. The selected status of SoundCard is lost its state when i scroll down and return to top of SoundCard.I enclosed the sample picture here.

I'm reading documentation such as Capturing a stream or Loopback recording, but I can't find a good reproducible example (with includes, build instructions, etc.) about how to record chunks from a Loopback audio device (sometimes called "What you hear", "Stereo Mix") with Windows WASAPI.

Would you have a simple reproducible example showing how to record audio chunks in a loop from a WASAPI device, in C++?

Here is a similar (working) example in Python:

I'm just beginning to get the basic funtions of the soundcard python module to work. However I cannot make my tkinter window show up first and wait until I press the run button to exicute the "def run()" code. It always does the "def run()" code first and then opens the window. What am I doing wrong?