SimulAudio Application v1.0
====================================

Based upon a 1-source-to-1-destination audio duplicator that I had and then 
refactored into the current 1-source-to-N-destinations fan-out design. 
We use it daily to listen to Windows audio on multiple Bluetooth speakers 
in different rooms in the house — currently a couple of Edifier R1280DBs in 
BT mode.


QUICK START (after installing)
------------------------------
1. Run SimulAudio.exe
2. Source Device: usually leave on the system default output (a non-BT
   device — Speakers, Headset, USB DAC, etc.). The app captures whatever
   Windows is rendering to that device.
3. Destination Devices: pick one or more BT speakers from the
   "Add destination" dropdown and click Add. Repeat for each speaker.
4. Click "Start Worker Task". You'll see "Buffering..." for ~1 second
   then "Active" — audio should start playing on all selected
   destinations.
5. Your selections (and the auto-reconnect setting) are saved
   automatically and restored on the next launch.


WHAT THIS APPLICATION DOES
---------------------------
Captures audio from a chosen output device using WASAPI loopback, then
fans the same stream out in parallel to N other output devices in
real-time. Each destination has its own ring buffer and (when needed)
its own sample-rate converter, so a slow or laggy destination can't
back-pressure the others.

The point: you can play system audio on two or more BT speakers in
different rooms with closely matching latency, instead of one trailing
the other.


REQUIREMENTS
------------
- Windows 10 or Windows 11
- .NET 9.0 Runtime installed
- Two or more audio output devices (one source, one or more destinations)


END USER FILES (when installed)
-------------------------------
- SimulAudio.exe       - The application
- SimulAudio.dll       - Application assembly
- NAudio*.dll          - Audio library (locally built fork)
- SimulAudio.runtimeconfig.json / .deps.json - Runtime config
- README.txt           - This file
- USER_GUIDE.md        - How to use the app


DEVELOPERS
----------
Built and developed in VS Code with the C# Dev Kit extension.

Prerequisites:
  - .NET 9.0 SDK
  - (For installer) Inno Setup 6 at the standard install path

The NAudio dependency is a local fork shipped under SimulAudio/Naudio/
(adds IDisposable to WaveInEventArgs to address a GC-pressure crash
seen in the stock library). It's referenced via <Reference> in the
.csproj — there is no NuGet step.

Build (Debug or Release):
    dotnet build SimulAudio.sln -c [Debug|Release]

Publish framework-dependent Release for distribution:
    dotnet publish SimulAudio/SimulAudio.csproj -c Release -r win-x64 ^
        --self-contained false -o publish

Build the installer:
    "C:\Program Files (x86)\Inno Setup 6\ISCC.exe" SimulAudioInstaller.iss

The Build-Installer.bat and Publish-Release.bat wrappers exist for
double-click use; they end with `pause` so they don't fit running from
a non-interactive shell.

See plans/current-design.md for the full architecture overview, and
plans/build-steps.md for the exact command sequence used to ship.


TROUBLESHOOTING
---------------
- If a destination doesn't appear in the dropdown, make sure it's
  connected and active in Windows Sound settings.
- If audio is dropping out, try a higher Buffer Configuration setting
  (the slider). The default "Balanced" is 2 seconds; "High Stability"
  is 5 seconds. Larger = more resilient to BT codec hiccups,
  noticeably longer startup delay.
- If a destination disappears (BT speaker powered off), the worker
  detects it and stops that destination's playback while keeping the
  others going. With Auto-Reconnect Bluetooth on, the app will pick
  the device back up when it reappears.
- For deeper diagnostic info, see %LOCALAPPDATA%\SimulAudio\crash.log
  (only populated if the app encounters an unhandled exception).


SUPPORT
-------
For usage questions, see USER_GUIDE.md.
For architecture / design questions, see plans/current-design.md.


VERSION
-------
Version 1.0 - Initial release of this better version.


CREDITS
-------
Thanks to Mark Heath and everyone who worked on NAudio.