VirtualDesktopSwitcher

Automatically switches the Preferred Codec in Virtual Desktop Streamer on a timer silently, without bringing the Streamer settings window to the foreground.

Prefer no injection? A self-contained PowerShell variant that drives the Streamer UI through Windows UI Automation lives on the uia-powershell branch.

Why this exists

There's a known issue on Meta headsets where streaming FPS drops after roughly 20–30 minutes of continuous play. Changing the codec forces the encode pipeline to reinitialize, which clears the drop and restores smooth frames.

Doing that by hand every half hour sucks, or is just not feasible for sim racing. This tool automates the workaround: it toggles between two codecs (or rotates a list) on an interval, so the stream resets on its own before the slowdown sets in. The default interval is 25 minutes; if you still see drops (some people experience at like 15 minutes?) lower it. It's a workaround until Meta fixes the garbage that is the Quest OS.

How it works

The rotator sets the codec from inside the Streamer process, writing the same live managed setting the Streamer UI itself uses:

VirtualDesktop.Streamer.StreamerSettings.Default.PreferredCodec

Because it sets the live setting directly, the switch takes effect immediately and the Streamer window never has to come to the foreground. Each switch:

1. VirtualDesktopSwitcher.exe injects VdCodecPayload.dll into VirtualDesktop.Streamer.exe (via EasyHook).
2. The payload loads VdCodecWorker.dll into Streamer's default AppDomain.
3. The worker reads or sets StreamerSettings.Default.PreferredCodec and writes the result back to the rotator.

This in-process approach is resilient across Streamer versions as long as that managed setting path stays stable. Tested against Virtual Desktop Streamer 1.34.18 with EasyHook 2.7.7097.

Requirements

• Windows (x64)
• Virtual Desktop Streamer installed, and running or startable
• The rotator must run at the same elevation level as the Streamer

Started with Windows? If Virtual Desktop Streamer launched automatically at sign-in, the rotator may not be able to reach it. Fully exit the Streamer (tray icon → Exit) and reopen it manually before running the rotator.

Heads up: because this uses process injection, antivirus or SmartScreen may flag unsigned builds. If you'd rather not inject at all, use the UI Automation fork.

Quick start

Download a release, unzip it, and run the executable from that folder:

.\VirtualDesktopSwitcher.exe

With no codec arguments, it reads the current codec and opens a small popup asking which different codec to toggle with, whether to beep before timer switches, and how many minutes to wait between switches (default 25, range 1–10080).

Prefer to build it yourself? See Building from source.

Usage

# Interactive setup, but start the timer at 15 minutes
.\VirtualDesktopSwitcher.exe --interval-minutes 15

# Explicit toggle pair on a 25-minute timer
.\VirtualDesktopSwitcher.exe --codecs HEVC10bit,HEVC --interval-minutes 25

# Beep during the final 5 seconds before each timer switch
.\VirtualDesktopSwitcher.exe --codecs HEVC10bit,HEVC --interval-minutes 25 --beep-warning

# Keep H.264+ active, briefly switching to H.264 to reset the stream every 25 minutes
.\VirtualDesktopSwitcher.exe --codecs H264Plus,H264 --interval-minutes 25 --switch-back

# Same, but stay on H.264 for 500 ms before switching back
.\VirtualDesktopSwitcher.exe --codecs H264Plus,H264 --interval-minutes 25 --switch-back --switch-back-delay-ms 500

# Switch once and exit
.\VirtualDesktopSwitcher.exe --codecs HEVC10bit,HEVC --once

# Switch immediately, then keep rotating on the timer
.\VirtualDesktopSwitcher.exe --codecs HEVC10bit,HEVC --switch-immediately

# Set one exact codec and exit
.\VirtualDesktopSwitcher.exe --target-codec HEVC10bit

# Show help
.\VirtualDesktopSwitcher.exe --help

Options

Option	Description
--codecs <list>	Comma-separated codec rotation list. Skips the popup.
--interval-minutes <n>	Minutes between switches. Default 25, range 1–10080.
--beep-warning	Beep during the final 5 seconds before each timer switch.
--no-beep-warning	Keep timer switches silent. Default.
--target-codec <codec>	Set one exact codec and exit.
--once	Switch to the next codec once and exit.
--switch-immediately	Switch immediately before entering the timer loop.
--switch-back	Treat the first of exactly two codecs as preferred. At each interval, switch to the second codec, wait for the switch-back delay, and restore the first. The preferred codec is also restored when the tool starts.
--switch-back-delay-ms <n>	Milliseconds to stay on the temporary codec before restoring the preferred one. Default 50, range 0–60000.
--streamer-path <path>	Path to VirtualDesktop.Streamer.exe (used to launch it if not running).
--timeout-seconds <n>	Helper timeout in seconds. Default 15, range 1–300.

Codec codes

Automatic, H264, H264Plus, HEVC, HEVC10bit, AV110bit

The interactive popup hides the currently selected codec, since the toggle target must differ from the current selection. Some GPUs or headsets do not support every codec.

With --switch-back, specify exactly two codecs. The first is the preferred codec and the second is only used temporarily to reset the stream. For example, --codecs H264Plus,H264 --switch-back keeps H.264+ selected between resets. The interactive popup offers the same behavior: check Switch back to, pick the codec to keep (it defaults to the current one), and pick the delay in milliseconds.

Building from source

Generated binaries are intentionally kept out of git. The build script downloads EasyHook from NuGet and compiles everything from source, no .NET SDK required, just the .NET Framework compiler that ships with Windows.

powershell -NoProfile -ExecutionPolicy Bypass -File .\build.ps1 -Package

The script:

• downloads pinned EasyHook 2.7.7097 from NuGet
• compiles the .NET Framework x64 executable and helper DLLs using C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe
• writes the release folder under dist\
• writes artifacts\VirtualDesktopSwitcher.zip when -Package is passed

A packaged release contains:

VirtualDesktopSwitcher.exe   VdCodecPayload.dll   VdCodecWorker.dll
EasyHook.dll   EasyHook64.dll   EasyLoad64.dll   EasyHook64Svc.exe
README.md   LICENSE   THIRD-PARTY-NOTICES.md

Source layout

src\VdCodecRotator\Program.cs                     CLI, timer loop, injection client
src\VdCodecRotator.Payload\PayloadEntryPoint.cs   EasyHook entry point
src\VdCodecRotator.Worker\StreamerCodecWorker.cs  reads/sets the live setting
build.ps1                                         builds and packages the release
test-package.ps1                                  verifies the packaged release
.github\workflows\                                CI build and tagged releases

Notes

• This project is not affiliated with Virtual Desktop, Inc.
• The selected toggle codec only needs to be different from the current one.
• Release packages bundle third-party notices for EasyHook and UDIS86 in THIRD-PARTY-NOTICES.md.

License

MIT. See LICENSE.