ovos-tools

This repository has documentation, scripts and other files to install and work with the Open Voice Operating System (OVOS).

This README document describes how to build a Personal Voice Assistant from the ground up.

The build

The environment used to develop the code and write this document is a RasPi 4B with 4 GB of memory, running Ubuntu Desktop 22.04 inside an enclosure. Details on the hardware and CNC G-code to build a smart boombox are here: https://github.com/mike99mac/ovos-tools/tree/main/gcode

The Raspberry Pi OS (aka Raspbian) versions 10 (buster) and 11 (bullseye) were also tested. However, this code and these steps should be relatively portable to any hardware that can run any Linux.

The overall steps to build an OVOS box are:

• Acquire the hardware
• Flash Linux to a memory device
• Connect the hardware
• Install and configure Linux
• Install and use ovos-tools
• Test microphone and speakers
• Install and configure OVOS
• Start Minimy and use it!

Acquire the hardware

The recommended hardware is a Raspberry Pi (RasPi) 4B, or 400 with 4 or 8 GB of memory. The RasPi 5 is now available and is more powerful and hopefully easier to procure than the 4 was.

For a microphone, a flat, disk type with a mute/unmute switch for visible privacy is recommended. Don't use a cheap one. It is best to move the microphone away from the speakers and closer to the center of the room.

You can start with just about any speaker(s) with a 3.5mm jack that will plug into the RasPi. A DAC HAT plugged on top of the RasPi will greatly improve audio quality.

Flash Linux to a memory device

The RasPi boots from a micro-SD card that plugs into its underside. A 32 GB card or larger is recommended. You need to prime the pump and copy a Linux distribution to it.

The following three flavors of two Linux distributions are supported. Note that Raspbian has been renamed to Raspberry Pi OS but in many places the original name is still used.

• Ubuntu 22.04.2 LTS
  • LTS stands for Long Term Support - Canonical promises to support it for at least five years.
• Raspbian GNU/Linux 10 (buster)
• Raspbian GNU/Linux 11 (bullseye)

Prepare on Linux

If you have a Linux box with an SD card port, you can use rpi-imager to copy the Linux image. To do so, perform the following tasks.

• Put a micro-SD card into an SD adapter.
• Plug the SD adapter into the card reader.
• If you don't have it already, install the tool.

sudo apt-get install -y rpi-imager

• Run the tool.

rpi-imager

• To flash a Linux image to the card, perform the following steps:

  • Select the type of Raspberry Pi Device you have - a 4 or a 5.

  • Select one from Operating System.

    • Raspberry Pi OS (64-bit) Debian Bookworm with Desktop
    • Raspberry Pi OS (64-bit) Debian Bullseye with Desktop
    • Raspberry Pi OS (other) => Raspberry Pi OS Lite (64-bit)
    • Raspberry Pi OS (legacy) => Debian Buster with Desktop
    • Other General Purpose OS => Ubuntu => Desktop 22.04.2 LTS (64-bit)

  • Select the Storage device. You should see just one micro-SD card in the dropdown menu. If you don't see any entry, your SD card has not been recognized.

  • Click Write.

  • If you are challenged for credentials, enter the password of the current user.

You should see a progress indicator as the image is copied to the SD card. It can take quite a while, depending on OS size and throughput.

Prepare an SD card on Windows

If you only have access to a Windows system Install the Win 32 disk imager from https://sourceforge.net/projects/win32diskimager/

There is now a port of rpi-imager to Windows. See: https://downloads.raspberrypi.org/imager/imager_latest.exe

Connect the hardware

For the initial setup, a keyboard, monitor and mouse are needed. You can access the Internet using either Wi-Fi or with an Ethernet cable.

To connect all the computer hardware, perform the following steps:

• Plug the micro-SD card into the back underside of the RasPi.
• If you have wired ethernet, plug it in to the RJ-45 connector on the RasPi.
• Connect the mouse and keyboard to the USB slots.
• Connect the monitor to the RasPi with an appropriate micro-HDMI cable. The RasPi 4 two micro HDMI ports - only the left one sends output at boot time.
• If you have a USB drive with music files on it, plug it in to a USB slot.
• Now that all the other hardware is connected, plug the 5v power supply with a USB-C end into the RasPi 4. An official RasPi power supply is recommended to avoid undervoltage warnings. If you have an inline switch, turn it on.

Install and configure Linux

To install and configure Ubuntu Desktop Linux, perform the following sections.

• Boot the RasPi
• Initial Ubuntu Desktop configuration -or- Initial Raspbian Desktop configuration
• Install the SSH server
• Start a terminal or SSH session
• Update and upgrade your system

Boot the RasPi

When you supply power to the RasPi, it should start booting. On the top, back, left side of a RasPi 4 there are two LEDs:

• The LED to the left should glow solid red. This signifies it has 5V DC power.
• The LED to the right should flicker green. This signifies that there is communicaiton with the CPU. If there is a red light, but no green one, it's likely the micro-SD card does not have Linux properly installed.

The RasPi 5 has a single LED that blinks both red and green.

• For Ubuntu, you should see a rainbow colored splash screen on the monitor, then the Ubuntu desktop should initialize.
• For Raspberry Pi OS, you should see a red raspberries at the top of the screen.

IMPORTANT: Never turn the RasPi off without first shutting Linux down with the halt or similar command. Doing so can damage the operating system and possibly even the RasPi itself.

Initial Ubuntu Desktop configuration

If you are installing Raspbian, skip to the next section.

A welcome screen should open on the monitor. Perform the following steps:

• On the Welcome window, choose your language and click Continue.
• On the Keyboard layout window, choose your layout and click Continue.
• On the Wireless window, if you are not using a hard-wired Ethernet, click Connect and configure a Wi-Fi network. You must know the network SSID and will probably be prompted for a password.
• On the Where are you? window, choose your time zone.
• On the Who are you? window, set the following values:
  • Set your name.
  • Set your computer’s name (host name).
  • For a user name and password pi is recommended as it is documented in the reminder of this document.
  • For the last option, Log in automatically is recommended.
  • Click Continue.
• The install process will take a number of minutes configuring and will reboot the computer.
• When the system finishes rebooting, an Online Accounts window should appear. Click Skip.
• Click Next at the Enable Ubuntu Pro window.
• Choose an option on the Help Improve Ubuntu window and click Next.
• Click Next at the Privacy window.
• Click Done at the Ready to go window.

Ubuntu Desktop 22.04 should now be installed.

Initial Raspbian Desktop configuration

If you are installing Ubuntu, skip this section.

To install and configure Raspbian, perform the following steps:

• At the Welcome to the Raspberry Pi Desktop! window => click Next.
• At the Set Country window - choose your country, language and time zone and click Next.
• At the Create User window - The user name must be pi.
• At the Set up screen window - Check the box if you see a black box around the monitor and click Next.
• At the Select WiFi Network window - choose your network and click Next.
  • At the Enter WiFi Password window, enter the password and click Next.
• At the Update Software window - click Skip - the upgrade will be done from a terminal session.
• At the Setup complete window - click Done or Restart.

Setting up the SSH server on Ubuntu

If you are installing Raspbian, skip to the next section.

The secure shell (SSH) server is not installed by default on Ubuntu desktop. Install it so you can access your system remotely. To do so, perform the following steps:

• Open a terminal session by right-clicking the mouse anywhere on the desktop and choosing Open in Terminal. You should see a console window open.
• Show the contents of the /etc/os-release file just to confirm the Ubuntu release level.

cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.2 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.2 LTS (Jammy Jellyfish)"
...

• Update and upgrade your system which installs the latest code for all installed packages.

sudo apt-get update

sudo apt-get upgrade -y

• Install the openssh-server package, with the following command. You will be prompted for your password.

sudo apt-get install -y openssh-server

• After it installs sshd should be running. Verify with the following command:

service sshd status

Setting up the SSH server on Raspbian

If you are installing Ubuntu, skip this section.

The secure shell (SSH) server is installed by default on Raspbian, but not running.

To start it now, and enable it at boot time, perform the following steps:

• Click the red Raspberry icon in the upper left corner, then in the drop-down menu choose Accessories then Terminal.

• From the terminal session, start the SSH server for the current session.

systemctl start ssh

• Set the SSH server to start at boot time.

systemctl enable ssh

Start a terminal or SSH session

You can continue to work from a terminal session or you can SSH in to your new Linux system. To SSH in, perform the following steps.

• Get your IP address. You should have either a Wi-Fi (wlan0) or a hard-wired (eth0) connection. To verify, enter the following command.

ip a
1: lo:
...
2: eth0:
...
3: wlan0:
...
inet 192.168.1.229

SSH as the user pi, if you want to continue from another system. You can use putty to SSH in from a Windows box, or just use the ssh command from a Linux or macOS console.

IMPORTANT: Do not run as root. Doing so will almost certainly screw up your system. Users other than pi ideally will work as the environment variable $HOME is used in scripts, however, this has never been tested.

Install and use ovos-tools

The ovos-tools repo has been developed to help with the installation, configuration, use and testing of the free and open personal voice assistants.

To install ovos-tools perform the following steps:

• Install git and vim as they are needed shortly.

sudo apt-get install -y git vim

• Make vim the default editor.

sudo update-alternatives --install /usr/bin/editor editor /usr/bin/vim 100

• Allow members of the sudo group to be able to run sudo commands without a password, by adding NOPASSWD: to the line near the bottom of the file.

sudo visudo

...
%sudo   ALL=(ALL:ALL) NOPASSWD: ALL
...

• Clone the ovos-tools package in the pi home directory with the following commands:

git clone https://github.com/mike99mac/ovos-tools.git

• Change to the newly installed directory and run the setup script. It will copy scripts to the directory /usr/local/sbin which is in the default PATH.

cd ovos-tools
sudo ./setup.sh

The ovos-tools repo is now installed.

Further customize

The script install1, in the ovos-tools package you just installed, runs many commands and thus saves typing, time and possible errors.

It performs the following tasks:

• Installs the cifs-utils curl locate mpc mpd net-tools pandoc pulseaudio python3 python3-pip python3-rpi.gpio python3-venv packages

• Sets vim to a better color scheme and turns off the annoying auto-indent features

• Adds needed groups to users pi and mpd

• Copies a .bash_profile with helpful OVOS shortcuts to the user's home directory

• Turns default and vc4 audio off and does not disable monitor overscan in the Linux boot parameters file.

• Changes a line in the rsyslog configuration file to prevent kernel message floods

• Copies a systemctl configuration file to mount /var/log/ in a tmpfs which helps prolong the life of the micro-SD card

• Sets pulseaudio to start as a system service at boot time, and allows anonymous access so audio services work

• Configures mpd, the music player daemon, which plays most of the sound

• Turns off bluetooth as Linux makes connecting to it difficult, while most amplifiers make it easy

• Run the install1 script in the home directory. It will take a couple of minutes.

cd
install1

Test the changes

• Test your environment with the newly installed lsenv script which reports on many aspects of your Linux system.

lsenv

The output should show:

• Neither Neon, OVOS, nor Minimy are installed
• Neither pulseaudio nor mpd are running
• Useful information such as IP address, CPU temperature, root file system, CPU and memory usage
• None of the file systems frequently written to are mounted as in-memory tmpfs file systems

Some of the changes made by install1 will not be realized until boot time. To test this, perform the following steps:

• Reboot your system

sudo reboot

• Restart your SSH session when it comes back up.
• Run lsenv again to see how the environment has changed.

You should see these changes:

• pulseaudio and mpd are now running.
• The /var/log/ directory is now an in-memory tmpfs file system.

Test microphone and speakers

It is important to know your microphone and speakers are working. There are scripts in ovos-tools named testrecord and testplay. They are wrappers around the arecord and aplay commands designed to make it easier to test recording audio to a file and playing it back on the speaker(s).

• To test your microphone and speakers, issue the following command then speak for up to five seconds.

testrecord

Testing your microphone for 5 seconds - SAY SOMETHING!
INFO: running command: arecord -r 44100  -f S24_LE -d 5 /tmp/test-mic.wav
Recording WAVE '/tmp/test-mic.wav' : Signed 24 bit Little Endian, Rate 44100 Hz, Mono
Calling testplay to play back the recording ...
Playing WAVE '/tmp/test-mic.wav' : Signed 24 bit Little Endian, Rate 44100 Hz, Mono

You should hear your words played back to you. If you do not, you must debug the issues - there's no sense in going forward without a microphone and speaker(s).

At this point your system should have a solid sound and microphone stack running, especially mpd and pulseaudio, and all software necessary to install one of the three personal voice assistants.

If you want to install OVOS, perform the steps in the next section. If you want to install Neon, perform the steps in section after that. If you want to install Minimy, go to https://github.com/mike99mac/minimy-mike99mac

Install and configure OVOS

Use the OVOS installer to install it in a virtual environment.

sh -c "curl -s https://raw.githubusercontent.com/OpenVoiceOS/ovos-installer/main/installer.sh -o installer.sh && chmod +x installer.sh && sudo ./installer.sh"

Answer questions as they are asked.

• Reboot the system

sudo reboot

When the installer finishes, OVOS should be running.

After a reboot, you should notice the prompt (ovos) showing that you are in a virtual environment.

Run OVOS

The scripts startovos and stopovos can be used to start and stop processes. Each skill and service run as process and use the message bus or file system to synchronize. Their output is written to the logs/ directory under the main install directory.

• Run lsenv again. You should see two changes:

  • OVOS is now running - the output showing user and system skill processes.
  • The file systems frequently written to are now mounted over in-memory tmpfs's.

Install and configure Neon

The scripts installneon was written to make it easy to install Neon. To use it, perform the following steps.

• Clone the Neon core repository:

git clone https://github.com/NeonGeckoCom/NeonCore

• Run installneon:

installneon

• If the user and group docker do not exist, they will be created, and the group will be added to the user you are running from. You will see the following messages and will need to start a new shell and run installneon again.

...
Adding docker as a group of pi ...
24-06-26-16-27-17 - Running: sudo gpasswd -a pi docker ...
Adding user pi to group docker
Please start a new shell and run /usr/local/sbin/installneon again ...
...

• Reboot the system

sudo reboot

The buttons process

The smart boombox model with the RasPi on-board has three pushbuttons on the front panel to allow quick access to previous track, pause/resume, and next track operations. If you hold the middle button for more that two seconds, it does a stop function, which also clears the music queue. A new buttons system skill traps button presses and sends corresponding messages to the bus.

If you want to add buttons to your enclosure, attach them to the following GPIO pins:

+-----+--------+-------------------------------+
| Pin | Label  | Description                   |
|-----|--------|-------------------------------|
| 9   | GND    | Ground common to all buttons  |
| 11  | GPIO17 | Previous track                |
| 13  | GPIO27 | Pause/resume                  |
| 15  | GPIO22 | Next track                    |
+-----+--------+-------------------------------+

Here is a source of purchasing pushbuttons: https://www.amazon.com/dp/B09C8C53DM

TODO: On the other boombox model, the computer is a RasPi 400 which is offboard, and the GPIO pins are not easily accessible. That will need new code to use the arrow keys on the RasPi 400 for the same function.

Debugging

Maybe everything will work perfectly the first time, and you won't have to debug (but we know how that goes :))

Following are some debugging resources.

• Many, many debug statements have been added to the code. In most classes, every function has at least one log statement when in debug mode with the class, the function, and the parameters passed.

• Log files are in $HOME/minimy/logs.

  • Show the log files.

    $ cd $HOME/minimy/logs

    $ ls

    intent.log media_player.log skills.log stt.log tts.log

  • When Minimy is running, you can watch all the log files get populated in real time with the following command:

    tail -f *

• There is an HTML file with JavaScript code that displays the message bus in real time. If you do not have a Web server running, you must view it from the local host.

  • Start a browser on the box you're installing on and point it to file:///home/pi/minimy/display/sysmon.html
  • You should see all messages written to the message bus and the associated data.

• The sortlogs script - merges and sorts all the log files by timestamp and saves them to /tmp. The merged output is often easier to peruse than the individual files.

  $ cat sortlogs
  #!/bin/bash
  #
  # sortlogs - merge and sort all log files
  #
  tmpFile="all.logs"
  cd $HOME/minimy/logs
  if [ -f $tmpFile ]; then                   # old one exists
    rm $tmpFile
  fi
  for i in *.log; do                         # copy all log files
    cat $i >> $tmpFile
  done
  outFile="/tmp/logs-`date +\"%F-%T\"`"
  sort $tmpFile > $outFile                   # sort by timestamp
  echo "sorted logs saved to: $outFile"
  

• The stopminimy script calls sortlogs so every time you stop Minimy, there is a new log file copied to /tmp/ which persists across the starting and stopping of Minimy, unlike $HOME/minimy/tmp/.

  $ stopminimy
  ...
  killing process: pi        952424       1 10 16:25 pts/3    00:00:11 python3 framework/services/input/buttons.py ...
  killing process: pi        952425       1  7 16:25 pts/3    00:00:08 python3 framework/services/input/mic.py ...
  sorted logs saved to: /tmp/logs-2023-07-01-16:27:34
  

• There's a RELEASE-NOTES.md and TODO.md that show a history of the project and a wish list of things to do.

• Google searches, of course ...

• You can email me at mike99mac at gmail.com - can't promise anything, but I will try.

Reference

These reference sections follow:

• Vocabulary and examples
• Other Documentation

Vocabulary and examples

In the samples that follow, (words) in parenthesis are the actual words spoken, while {words} in curly brackets become variables populated with the actual words spoken. When (multiple|words|) are separated by vertical bars, any of those can be spoken, and a trailing vertical bar means that word can be omitted.

Connectivity skill

TODO: Finish writing this skill.

Following is the Connectivity skill vocabulary.

Following are examples of Connectivity skill requests:

Email skill

Following is the Email skill vocabulary.

(compose|create|new|start) email
send email

Following are examples of Email skill requests:

• start email
• ... dialog continues ...
• send email

Example1 skill

Following is the Example1 skill vocabulary.

(run|test|execute) example one

Following are examples of Example1 skill requests:

• run exmple one

Help skill

TODO: Finish the code for this skill!

Following is the Help skill vocabulary.

Following are examples of Help skill requests:

MPC skill

The MPC skill can:

• Play from your music library
• Play Internet radio stations
• Play Internet music
• Play NPR news
• Create, delete, manage and play playlists (TODO: finish this code)
• Perform basic player operations

Following are the vocabularies for the MPC skill:

• Music library vocabulary:

  play (track|song|title|) {track} by (artist|band|) {artist}
  play (album|record) {album} by (artist|band) {artist}
  play (any|all|my|random|some|) music 
  play (playlist) {playlist}
  play (genre|johnra) {genre}    
  

• Internet radio vocabulary:

  play (the|) radio
  play music (on the|on my|) radio
  play genre {genre} (on the|on my|) radio
  play station {station} (on the|on my|) radio
  play (the|) (radio|) station {station}
  play (the|) radio (from|from country|from the country) {country}
  play (the|) radio (spoken|) (in|in language|in the language) {language}
  play (another|a different|next) (radio|) station
  (different|next) (radio|) station
  

• Internet music vocabulary:

  play (track|artist|album|) {music} (from|on) (the|) internet
  

• NPR News vocabulary:

  play (NPR|the|) news
  

• Playlist vocabulary:

  (create|make) playlist {playlist}
  (delete|remove) playlist {playlist}
  add (track|song|title) {track} to playlist {playlist}
  add (album|record) {album} to playlist {playlist}
  (remove|delete) (track|song|title) {track} from playlist {playlist}
  list (my|) playlists
  what playlists (do i have|are there)
  what are (my|the) playlists
  

• Basic player commands vocabulary:

  previous (song|station|title|track|)
  next (song|station|title|track|)
  pause                               # stop music but maintain queue
  resume
  stop                                # stop music and clear queue
  
  increase volume
  decrease volume
  

Following are examples of MPC skill's requests:

• Play track one and only by artist adele.
• Play album abbey road
• Play genre blues on the radio
• Play language german on the radio
• Play track stressed out by artist twenty on pilots
• Play npr news
• Play artist the chainsmokers from the Internet

Timedate skill

Following is the Timedate skill vocabulary:

what time (is it|)
what (is|) (today's|) date
what day (of the week|) (is it|)

Following are examples of skill's requests:

• What time is it?
• What is today's date
• What day of the week is it

Weather skill

Following is the Weather skill vocabulary:

(what's|what is) (the|) weather (forecast|)

Following are examples of Weather skill requests:

• What's the weather?

Wiki skill

The Wiki skill is a fallback skill. As such it does not have a vocabulary

TODO: Add Ask wikipedia {question}

More documentation

There is more documentation, by the original author Ken Smith, here: https://github.com/ken-mycroft/minimy/tree/main/doc

Installing and running faster-whisper

Trying to install faster-whisper on a Raspberry Pi 5.

Mike Gray's writeup on how to do this is here: https://blog.graywind.org/posts/fasterwhisper-stt-server-script/

To prepare for the install:

• Reflashed RasPiOS onto a micro-SD card and installed Linux.
• Reinstalled ovos-tools from https://github.com/mike99mac/ovos-tools
• Ran install1 from ovos-tools.

To install it, perform the following steps.

• Get Mike Gray's script:

cd 
wget https://gist.githubusercontent.com/mikejgray/a7067743a3c50ed74f05a401fa6bb9ce/raw/73f9b87082573017d8c486f42d43eecd8181982c/fasterwhisper-setup.sh

• Copy to /usr/local/sbin:

sudo cp fasterwhisper-setup.sh  /usr/local/sbin
cd /usr/local/sbin
sudo chown pi.pi fasterwhisper-setup.sh
chmod +x fasterwhisper-setup.sh

• Run it and save output:

fasterwhisper-setup.sh | tee $HOME/fasterwhisper-setup.out

• Make it a service and set it to run at boot time:

sudo cp ~/ovos-stt-server.service /etc/systemd/system/ovos-stt-server.service
sudo systemctl daemon-reload
sudo systemctl enable ovos-stt-server.service

• Start the service:

sudo systemctl start ovos-stt-server.service

• Test playing a sample audio file in the ovos-tools directory. It is an 11 second excerpt from a speech by John F. Kennedy.

aplay /home/pi/ovos-tools/jfk.wav

• Send the sample audio file to the flask Web server using the IP address and port 8080:

curl -X POST -H "Content-Type: audio/wav" -i --data-binary -F data="/home/pi/ovos-tools/jfk.wav" http://192.168.1.102:8080/stt
$ curl -X POST -H "Content-Type: audio/wav" -i --data-binary -F data="/home/pi/ovos-tools/jfk.wav" http://192.168.1.102:8080/stt
curl: (3) URL using bad/illegal format or missing URL
HTTP/1.1 500 INTERNAL SERVER ERROR
Server: Werkzeug/3.0.3 Python/3.11.2
Date: Sun, 02 Jun 2024 17:55:16 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 265
Connection: close

<!doctype html>
<html lang=en>
<title>500 Internal Server Error</title>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.</p>

Here is the output from the flask Web server:

Traceback (most recent call last):
  File "/home/pi/STT_venv/lib/python3.11/site-packages/flask/app.py", line 1473, in wsgi_app
    response = self.full_dispatch_request()
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/STT_venv/lib/python3.11/site-packages/flask/app.py", line 882, in full_dispatch_request
    rv = self.handle_user_exception(e)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/STT_venv/lib/python3.11/site-packages/flask/app.py", line 880, in full_dispatch_request
    rv = self.dispatch_request()
         ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/STT_venv/lib/python3.11/site-packages/flask/app.py", line 865, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/pi/STT_venv/lib/python3.11/site-packages/ovos_stt_http_server/__init__.py", line 34, in get_stt
    with AudioFile(fp.name) as source:
  File "/home/pi/STT_venv/lib/python3.11/site-packages/speech_recognition/__init__.py", line 274, in __enter__
    raise ValueError("Audio file could not be read as PCM WAV, AIFF/AIFF-C, or Native FLAC; check if file is corrupted or in another format")
ValueError: Audio file could not be read as PCM WAV, AIFF/AIFF-C, or Native FLAC; check if file is corrupted or in another format
192.168.1.102 - - [02/Jun/2024 13:55:16] "POST /stt HTTP/1.1" 500 -

• I tried installing flac, restarting flask and sending the request again - same result :((

sudo apt-get install flac