RDPiO

A from-scratch, GPU-accelerated Remote Desktop (RDP) client written in Rust — built for business work and gaming at the same time.

RDPiO implements the RDP protocol stack from the wire up — no third-party RDP library. On Windows it decodes H.264 on the GPU (Direct3D 11), spans multiple monitors, redirects your devices (drives, clipboard, audio, mic, camera, printer), and can ride a low-latency UDP side-band transport.

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Quick install

Windows: one line in PowerShell. No admin needed.

irm https://raw.githubusercontent.com/IOServicesLabs/RDPiO/main/install.ps1 | iex

It installs the latest release to %LOCALAPPDATA%\Programs\rdpio, adds a Start menu shortcut and puts rdpio on your PATH, then opens the launcher. From then on rdpio keeps itself up to date (signed releases; see Updates). For nightly builds, run $env:RDPIO_CHANNEL='nightly' first. install.ps1 shows the other options.

Or just the exe, with curl (built into Windows 10 and 11, from Command Prompt or PowerShell):

curl.exe -LO https://github.com/IOServicesLabs/RDPiO/releases/latest/download/rdpio.exe
curl.exe -LO https://github.com/IOServicesLabs/RDPiO/releases/latest/download/rdpio.exe.update
rdpio.exe

Keep rdpio.exe.update beside the exe. It's the release's signed manifest, and a Hyper host needs it to pass updates on to the devices that connect.

To stream this PC to your other devices (Hyper): in the launcher, open This PC and choose Set up Hyper. Then add a Hyper Direct connection on the laptop. The full walkthrough is in docs/hyper.md.

Quick start

Copy-paste one of these. Swap 192.168.1.50 / alice / the password for your own — the only required argument is --host.

Windows: download the latest release and connect:

irm https://github.com/IOServicesLabs/RDPiO/releases/latest/download/rdpio-windows-x86_64.zip -OutFile rdpio.zip
Expand-Archive rdpio.zip -DestinationPath . -Force
.\rdpio-windows-x86_64\rdpio.exe --host 192.168.1.50 --user alice --password 'hunter2' --insecure

Linux — same, but headless (it runs the protocol and logs frames; no window yet):

curl -L https://github.com/IOServicesLabs/RDPiO/releases/latest/download/rdpio-linux-x86_64.tar.gz | tar xz
RUST_LOG=info ./rdpio-linux-x86_64/rdpio --host 192.168.1.50 --user alice --password 'hunter2'

From source — any platform, needs Rust 1.77+ (and the MSVC toolchain on Windows):

git clone https://github.com/IOServicesLabs/RDPiO
cd RDPiO
cargo build --release -p rdp-client
./target/release/rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure

--insecure accepts a self-signed certificate, which is what a stock Windows host presents. Drop it once the host has a trusted cert.

CPU requirement: builds target x86-64-v3 (AVX2), so they need a 2013-or- newer CPU — Intel Haswell / AMD Excavator or later. The pixel-decode loops are the client's main CPU cost and AVX2 doubles their vector width, which is worth more than supporting hardware that predates the D3D11 GPU decoding this client already assumes. To build for an older machine, override the baseline: RUSTFLAGS="-C target-cpu=x86-64" cargo build --release -p rdp-client.

Beyond a plain connection, these two cover most of what people actually want:

# Business: all your monitors, a shared folder, and the local printer
rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure --multimon --drive C:\Shared --printer

# Gaming: latency-first, and render at 66% so the host encodes far fewer pixels
rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure --gaming --render-scale 0.66

More recipes in Run it; every flag is listed under Options.

Gaming beyond RDP's 60 fps: the Hyper Accelerator streams a gaming PC's real monitor at up to its full refresh rate over encrypted UDP, with its own password (no Windows sign-in needed) — see docs/hyper.md.

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What you can run today

Linux is a staged port: the protocol core is portable and already runs there. Rendering, input, and device backends are the remaining work — see PORTING.md.

Run it

Builds come from the Releases page: every push to main refreshes the nightly prerelease with a Windows .zip and a Linux .tar.gz, and v* tags get permanent releases.

rdpio --host HOST [--port N] [--user U] [--domain D] [--password P] [options]

A domain session — multi-monitor, with a shared folder, printer, and a download folder for files copied out of the session:

rdpio --host 192.168.1.50 --user alice --domain CORP --password 'hunter2' `
      --multimon --drive C:\Shared --printer --clipboard-dir C:\Downloads

Gaming / low latency — cheaper host encode plus client-side GPU upscaling. Best single knob if motion is choppy. --upscale fsr (AMD FidelityFX SR 1.0, runs on any GPU) reconstructs game imagery best; the default bicubic is the safer pick for mixed desktop + game use:

rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure `
      --gaming --render-scale 0.66 --upscale fsr

Render-scale also works across monitors — the host renders a smaller spanned desktop and the client upscales each monitor's slice back to its native panel:

rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure `
      --multimon --gaming --render-scale 0.66 --upscale fsr

A Windows 365 Cloud PC — signs in through the browser and lists your Cloud PCs to pick from:

rdpio --w365

Teams "Optimized" — run Teams A/V on the client instead of the Cloud PC:

rdpio --w365 --teams

A saved connection file, or a workspace feed on a non-default endpoint (--feed overrides https://rdweb.wvd.microsoft.com/api/arm/feeddiscovery):

rdpio --rdp-file .\CloudPC.rdp
rdpio --feed https://rdweb.wvd.microsoftonline.us/api/arm/feeddiscovery

Diagnose a session — mirror the log to a file (RUST_LOG sets the level):

$env:RUST_LOG = 'info'
rdpio --host 192.168.1.50 --user alice --password 'hunter2' --insecure --log-file rdpio.log

On Linux the same commands run headless (connection, TLS, NLA, activation, and decoded rectangles are logged) — set RUST_LOG=info to see the frame log.

If gaming feels choppy, the host is usually the bottleneck, not RDPiO — the encoder is the host's built-in RDP server. Lifting its default ~30fps cap and steadying CPU clocks are OS-side changes. See docs/host-tuning.md. RDPiO logs the achieved decode fps at RUST_LOG=info so you can measure each change.

Helper scripts (Windows)

run-rdpio.ps1 wraps the two common presets, so you don't have to remember the flag combinations:

.\run-rdpio.ps1 -Mode gaming -RdpHost 192.168.1.50 -User .\alice -Password 'hunter2'
.\run-rdpio.ps1 -Mode office -RdpHost 192.168.1.50 -User .\alice -Password 'hunter2'

Two more apply the OS-side tuning from docs/host-tuning.md. Both need an elevated shell and support -WhatIf, which prints every change without making it — always dry-run them first:

# On the RDP HOST: encoder/graphics policy (run elevated)
.\tune-rdpio-host.ps1 -WhatIf
.\tune-rdpio-host.ps1

# On either end: TCP, NIC offload/RSS, and QoS DSCP marking for rdpio.exe
.\tune-rdpio-network.ps1 -WhatIf
.\tune-rdpio-network.ps1 -LatencyProfile gaming

-LatencyProfile takes gaming, throughput (default), or wifi. Add -EnableJumboFrames only on a wired LAN — it hurts on Wi-Fi.

Options

Unknown flags are ignored with a warning (there is no --help yet), so a typo is silent — check the startup log if a flag seems to have no effect.

Connection

Display (Windows)

Performance

Redirection (Windows)

Windows 365 / AVD (Windows)

Diagnostics

Features

How it works

The "from scratch" boundary

"From scratch" means the protocol is ours. It does not mean reimplementing TLS, Kerberos, or an H.264 codec — those stay on the OS:

Workspace layout

The any crates are sans-I/O and compile/test on any host, which keeps the protocol logic unit-testable off-Windows.

Connection sequence

rdp-core drives the standard MS-RDPBCGR sequence over whichever transport the server negotiates:

1. X.224 connection request/confirm — advertise TLS/NLA, fall back to Standard RDP Security.
2. TLS upgrade, then CredSSP/NLA when the server requires it.
3. MCS Connect-Initial/Response carrying the GCC conference data (including the CS_MONITOR layout for multi-monitor).
4. Erect-Domain, Attach-User, per-channel Channel-Join.
5. Licensing, Demand-Active / Confirm-Active capability exchange.
6. Synchronize / Control / Font finalization → Active.
7. Fast-path output (bitmaps) and the RDPGFX dynamic channel (H.264) flow; DRDYNVC multiplexes graphics, display control, audio-input, and camera.

A server that offers multitransport triggers the optional UDP path: RDP-UDP handshake → TLS-over-UDP → RDPEMT tunnel → RDPGFX over UDP, with automatic fallback to TCP on any failure.

Development

cargo test --workspace                                    # 456 tests
cargo build --release -p rdp-client                        # the binary
cargo clippy --target x86_64-pc-windows-msvc -p rdp-client # Windows lint from any host

Cross-compiling a Linux binary from Windows needs a Linux C toolchain for ring; PORTING.md covers the cargo-zigbuild route. CI (.github/workflows/release.yml) builds and tests both platforms on every push and publishes the artifacts.

License

Licensed under either of MIT or Apache-2.0 at your option.

DEVELOPED IN THE USA