feat(host/windows): two-process secure-desktop step 4 — spawn helper + relay AUs

The SYSTEM host now sources the normal-desktop video from a user-session WGC
helper instead of capturing in-process (WGC won't activate as SYSTEM). New
`capture/wgc_relay.rs`: `HelperRelay::spawn` launches `m3-host wgc-helper` in the
interactive user session via CreateProcessAsUserW (WTSQueryUserToken →
DuplicateTokenEx(TokenPrimary) → lpDesktop="winsta0\\default", CREATE_NO_WINDOW)
with three anonymous pipes — stdout (framed Annex-B AUs → parsed back to
RelayAu), stdin (control: force-keyframe), stderr (helper logs → host tracing).
The host holds the SudoVDA keepalive (sole isolation/topology owner); the helper
captures by GDI name only.

m3.rs: `virtual_stream` dispatches to the new `virtual_stream_relay` when
`should_use_helper()` (running as SYSTEM, or PUNKTFUNK_FORCE_HELPER; disable with
PUNKTFUNK_NO_HELPER). The relay loop feeds the existing send thread — same
FEC/seal/paced-send path. Reconfigure rebuilds the output + re-spawns the helper;
keyframe requests forward over the control pipe; helper pts_ns (same-machine
monotonic clock) is used directly as capture_ns. Disconnect ends the stream
(step 6 adds the relaunch watchdog).

wgc_helper.rs: reads the stdin control byte to request an IDR; --bit-depth flag
threaded through so SDR 10-bit (Main10) negotiation reaches the helper's encoder.

cfg-gated windows-only; Linux/macOS build unaffected. Step 5 (DesktopWatcher mux
to host DDA on the Winlogon secure desktop) is next.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-06-16 07:43:20 +00:00
parent 7a814b5f18
commit 9f50b3930d
6 changed files with 635 additions and 3 deletions
+5
View File
@@ -136,6 +136,11 @@ windows = { version = "0.62", features = [
"Win32_System_WinRT_Graphics_Capture",
# WGC runs under SYSTEM via interactive-user impersonation (WGC won't activate as SYSTEM).
"Win32_System_RemoteDesktop",
# Two-process secure-desktop design: the SYSTEM host spawns the WGC helper in the interactive
# user session (CreateProcessAsUserW) with stdout/stdin redirected to anonymous pipes.
"Win32_System_Threading",
"Win32_System_Pipes",
"Win32_System_Environment",
] }
# Software H.264 encoder (GPU-less path + NVENC fallback). The default `source` feature statically
# compiles OpenH264 (BSD-2) — no system lib, builds on MSVC; nasm on PATH adds the SIMD fast path.
+2
View File
@@ -328,3 +328,5 @@ pub mod dxgi;
mod linux;
#[cfg(target_os = "windows")]
pub mod wgc;
#[cfg(target_os = "windows")]
pub mod wgc_relay;
@@ -0,0 +1,389 @@
//! Host-side WGC helper relay (Windows two-process secure-desktop design,
//! docs/windows-secure-desktop.md — step 4).
//!
//! WGC won't activate under the SYSTEM account, so the SYSTEM host can't capture the normal desktop
//! itself. Instead it spawns `m3-host wgc-helper` in the **interactive user session** (so WGC works)
//! via `CreateProcessAsUserW`, with the helper's **stdout** redirected to an anonymous pipe the host
//! reads. The helper ships framed Annex-B access units; this module parses them back into AUs the
//! host relays onto the live QUIC session (same `EncodedFrame` flow, just sourced over a pipe instead
//! of a local encoder). A second pipe carries a tiny **control** channel to the helper (stdin: force
//! keyframe), and the helper's **stderr** is forwarded line-by-line into host tracing so its logs are
//! visible from the SYSTEM host's console.
//!
//! Wire framing (must match `wgc_helper::write_au`): per AU
//! `[u32 magic "PFAU" LE][u32 len LE][u64 pts_ns LE][u8 keyframe][len bytes data]`.
use crate::capture::dxgi::WinCaptureTarget;
use anyhow::{bail, Context, Result};
use std::io::{BufRead, BufReader, Read, Write};
use std::sync::mpsc::{Receiver, SyncSender};
use std::sync::Mutex;
use windows::core::PWSTR;
use windows::Win32::Foundation::SetHandleInformation;
use windows::Win32::Foundation::{CloseHandle, HANDLE};
use windows::Win32::Foundation::{HANDLE_FLAGS, HANDLE_FLAG_INHERIT};
use windows::Win32::Security::{
DuplicateTokenEx, SecurityImpersonation, TokenPrimary, SECURITY_ATTRIBUTES, TOKEN_ALL_ACCESS,
};
use windows::Win32::System::Environment::{CreateEnvironmentBlock, DestroyEnvironmentBlock};
use windows::Win32::System::Pipes::CreatePipe;
use windows::Win32::System::RemoteDesktop::{WTSGetActiveConsoleSessionId, WTSQueryUserToken};
use windows::Win32::System::Threading::{
CreateProcessAsUserW, TerminateProcess, CREATE_NO_WINDOW, CREATE_UNICODE_ENVIRONMENT,
PROCESS_INFORMATION, STARTF_USESTDHANDLES, STARTUPINFOW,
};
/// Must match [`crate::wgc_helper`]'s `AU_MAGIC` ("PFAU").
const AU_MAGIC: u32 = 0x5046_4155;
/// One access unit relayed from the helper, in the helper's (= the host's, same machine) monotonic
/// clock — `pts_ns` is directly comparable to the host's `now_ns()`.
pub struct RelayAu {
pub data: Vec<u8>,
pub pts_ns: u64,
pub keyframe: bool,
}
/// A running USER-session WGC helper whose AUs the SYSTEM host relays. Drop kills the child + closes
/// the pipes; the reader threads then end on the broken pipe.
pub struct HelperRelay {
proc: HANDLE,
thread: HANDLE,
/// Host write end of the helper's stdin — control commands (force keyframe). Mutex so the relay
/// can be shared while the encode thread requests keyframes.
stdin_w: Mutex<HANDLE>,
/// Parsed AUs from the helper's stdout reader thread.
rx: Receiver<RelayAu>,
}
// HANDLEs are just kernel handle values; we own them for the relay's lifetime and close them on Drop.
unsafe impl Send for HelperRelay {}
unsafe impl Sync for HelperRelay {}
/// Control byte on the helper's stdin: force the next encoded frame to be an IDR (client decode
/// recovery). Mirrors `enc.request_keyframe()` in the single-process path.
const CTL_KEYFRAME: u8 = 0x01;
impl HelperRelay {
/// Spawn the helper in the interactive user session and start relaying its AUs. `target` is the
/// SudoVDA output the host already created (captured by GDI name only — the helper never touches
/// display topology). `(w, h, hz)` is the negotiated mode; `bitrate_kbps` the negotiated bitrate.
pub fn spawn(
target: &WinCaptureTarget,
mode: (u32, u32, u32),
bitrate_kbps: u32,
bit_depth: u8,
) -> Result<HelperRelay> {
let exe = std::env::current_exe().context("current_exe for helper spawn")?;
let exe = exe.to_string_lossy().into_owned();
let (w, h, hz) = mode;
// CreateProcessAsUserW takes a single mutable command line (argv[0] = exe).
let cmdline = format!(
"\"{exe}\" wgc-helper --gdi \"{}\" --target-id {} --mode {w}x{h}x{hz} --bitrate {bitrate_kbps} --bit-depth {bit_depth}",
target.gdi_name, target.target_id
);
tracing::info!(cmd = %cmdline, "spawning WGC helper in user session");
unsafe { spawn_inner(&cmdline, w, h, hz) }
}
/// Receive the next relayed AU. Distinguishes a `Timeout` (helper slow/stalled — keep waiting)
/// from `Disconnected` (helper exited → its stdout closed → reader thread ended → channel
/// dropped), which returns *immediately* and means the relay must stop, not spin.
pub fn recv_timeout(
&self,
dur: std::time::Duration,
) -> Result<RelayAu, std::sync::mpsc::RecvTimeoutError> {
self.rx.recv_timeout(dur)
}
/// Ask the helper's encoder for an IDR on the next frame (client decode recovery). Best-effort:
/// a write failure means the helper is gone — the caller's recv loop will see the disconnect.
pub fn request_keyframe(&self) {
let h = self.stdin_w.lock().unwrap();
let mut written = 0u32;
unsafe {
let _ = windows::Win32::Storage::FileSystem::WriteFile(
*h,
Some(&[CTL_KEYFRAME]),
Some(&mut written),
None,
);
}
}
}
impl Drop for HelperRelay {
fn drop(&mut self) {
unsafe {
// Terminate the child first so its WGC capture + NVENC session tear down, then close our
// handles (the reader threads end on the resulting broken pipe).
let _ = TerminateProcess(self.proc, 1);
let _ = CloseHandle(*self.stdin_w.lock().unwrap());
let _ = CloseHandle(self.proc);
let _ = CloseHandle(self.thread);
}
tracing::info!("WGC helper relay torn down");
}
}
/// Inheritable anonymous pipe (read, write). The caller marks whichever end the host keeps as
/// non-inheritable so the child only inherits its own end.
unsafe fn make_pipe() -> Result<(HANDLE, HANDLE)> {
let mut read = HANDLE::default();
let mut write = HANDLE::default();
let sa = SECURITY_ATTRIBUTES {
nLength: std::mem::size_of::<SECURITY_ATTRIBUTES>() as u32,
lpSecurityDescriptor: std::ptr::null_mut(),
bInheritHandle: true.into(),
};
CreatePipe(&mut read, &mut write, Some(&sa), 0).context("CreatePipe")?;
Ok((read, write))
}
/// Mark a handle non-inheritable (the host keeps it; the child must not get a copy).
unsafe fn no_inherit(h: HANDLE) {
let _ = SetHandleInformation(h, HANDLE_FLAG_INHERIT.0, HANDLE_FLAGS(0));
}
unsafe fn spawn_inner(cmdline: &str, w: u32, h: u32, hz: u32) -> Result<HelperRelay> {
// The user token of the active console session (requires the host to be SYSTEM).
let session = WTSGetActiveConsoleSessionId();
if session == 0xFFFF_FFFF {
bail!("no active console session (WTSGetActiveConsoleSessionId)");
}
let mut user_token = HANDLE::default();
WTSQueryUserToken(session, &mut user_token)
.context("WTSQueryUserToken (host must run as SYSTEM)")?;
// A primary token for CreateProcessAsUserW.
let mut primary = HANDLE::default();
let dup = DuplicateTokenEx(
user_token,
TOKEN_ALL_ACCESS,
None,
SecurityImpersonation,
TokenPrimary,
&mut primary,
);
let _ = CloseHandle(user_token);
dup.context("DuplicateTokenEx(TokenPrimary)")?;
// The user's environment block (PATH, USERPROFILE, …) so the helper resolves config + DLLs.
let mut env_block: *mut core::ffi::c_void = std::ptr::null_mut();
let _ = CreateEnvironmentBlock(&mut env_block, Some(primary), false);
// Three pipes: stdout (helper→host AUs), stdin (host→helper control), stderr (helper→host logs).
let (out_r, out_w) = make_pipe().context("stdout pipe")?;
let (in_r, in_w) = make_pipe().context("stdin pipe")?;
let (err_r, err_w) = make_pipe().context("stderr pipe")?;
// The host keeps out_r / in_w / err_r — none inheritable; the child inherits out_w/in_r/err_w.
no_inherit(out_r);
no_inherit(in_w);
no_inherit(err_r);
let mut si = STARTUPINFOW {
cb: std::mem::size_of::<STARTUPINFOW>() as u32,
dwFlags: STARTF_USESTDHANDLES,
hStdInput: in_r,
hStdOutput: out_w,
hStdError: err_w,
..Default::default()
};
// WGC needs the interactive desktop.
let mut desktop: Vec<u16> = "winsta0\\default\0".encode_utf16().collect();
si.lpDesktop = PWSTR(desktop.as_mut_ptr());
let mut cmd: Vec<u16> = cmdline.encode_utf16().chain(std::iter::once(0)).collect();
let mut pi = PROCESS_INFORMATION::default();
let created = CreateProcessAsUserW(
Some(primary),
None,
Some(PWSTR(cmd.as_mut_ptr())),
None,
None,
true, // inherit handles (the child's std ends)
CREATE_UNICODE_ENVIRONMENT | CREATE_NO_WINDOW,
Some(env_block),
None,
&si,
&mut pi,
);
// Clean up regardless of outcome: the child now owns its inherited ends; close our copies.
let _ = CloseHandle(out_w);
let _ = CloseHandle(in_r);
let _ = CloseHandle(err_w);
if !env_block.is_null() {
let _ = DestroyEnvironmentBlock(env_block);
}
let _ = CloseHandle(primary);
if let Err(e) = created {
let _ = CloseHandle(out_r);
let _ = CloseHandle(in_w);
let _ = CloseHandle(err_r);
return Err(e).context("CreateProcessAsUserW(wgc-helper)");
}
tracing::info!(pid = pi.dwProcessId, mode = %format!("{w}x{h}@{hz}"), "WGC helper spawned");
// stderr → host tracing, line by line.
let err_handle = HandleReader(err_r);
std::thread::Builder::new()
.name("wgc-helper-log".into())
.spawn(move || {
let r = BufReader::new(err_handle);
for line in r.lines() {
match line {
Ok(l) if !l.trim().is_empty() => tracing::info!(target: "wgc_helper", "{l}"),
Ok(_) => {}
Err(_) => break,
}
}
})
.ok();
// stdout → parsed AUs. Bounded so a stalled relay applies backpressure (the pipe then fills and
// the helper blocks on write — the same backpressure the single-process channel gives).
let (tx, rx) = std::sync::mpsc::sync_channel::<RelayAu>(3);
let out_handle = HandleReader(out_r);
std::thread::Builder::new()
.name("wgc-helper-au".into())
.spawn(move || au_reader(out_handle, tx))
.ok();
Ok(HelperRelay {
proc: pi.hProcess,
thread: pi.hThread,
stdin_w: Mutex::new(in_w),
rx,
})
}
/// Parse the AU framing off the helper's stdout and forward each AU. Ends (returns) when the pipe
/// breaks (helper exit) or the channel's receiver is dropped (relay torn down).
fn au_reader(mut r: HandleReader, tx: SyncSender<RelayAu>) {
loop {
let mut hdr = [0u8; 4 + 4 + 8 + 1];
if r.read_exact(&mut hdr).is_err() {
break;
}
let magic = u32::from_le_bytes([hdr[0], hdr[1], hdr[2], hdr[3]]);
if magic != AU_MAGIC {
tracing::error!(
magic = format!("{magic:#x}"),
"WGC helper AU stream desync — aborting relay"
);
break;
}
let len = u32::from_le_bytes([hdr[4], hdr[5], hdr[6], hdr[7]]) as usize;
let pts_ns = u64::from_le_bytes([
hdr[8], hdr[9], hdr[10], hdr[11], hdr[12], hdr[13], hdr[14], hdr[15],
]);
let keyframe = hdr[16] != 0;
// Bound the allocation — a corrupt length must not OOM the host. 64 MiB is far above any real
// AU (a 5K keyframe is a few MB).
if len > 64 * 1024 * 1024 {
tracing::error!(len, "WGC helper AU length implausible — aborting relay");
break;
}
let mut data = vec![0u8; len];
if r.read_exact(&mut data).is_err() {
break;
}
if tx
.send(RelayAu {
data,
pts_ns,
keyframe,
})
.is_err()
{
break; // relay dropped
}
}
}
/// Minimal `Read` over a Win32 pipe HANDLE (the windows crate doesn't impl `Read` on HANDLE).
struct HandleReader(HANDLE);
unsafe impl Send for HandleReader {}
impl Read for HandleReader {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
let mut read = 0u32;
let ok = unsafe {
windows::Win32::Storage::FileSystem::ReadFile(self.0, Some(buf), Some(&mut read), None)
};
match ok {
Ok(()) => Ok(read as usize),
// A broken pipe (helper exited) reads as ERROR_BROKEN_PIPE → report EOF (0).
Err(_) => Ok(0),
}
}
}
impl Drop for HandleReader {
fn drop(&mut self) {
unsafe {
let _ = CloseHandle(self.0);
}
}
}
/// Is this process running as the LOCAL SYSTEM account? Used to decide whether the two-process
/// secure-desktop path applies (only SYSTEM can `WTSQueryUserToken` + capture the Winlogon desktop).
pub fn running_as_system() -> bool {
use windows::Win32::Security::{GetTokenInformation, TokenUser, TOKEN_QUERY, TOKEN_USER};
use windows::Win32::System::Threading::{GetCurrentProcess, OpenProcessToken};
unsafe {
let mut token = HANDLE::default();
if OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &mut token).is_err() {
return false;
}
let mut len = 0u32;
let _ = GetTokenInformation(token, TokenUser, None, 0, &mut len);
if len == 0 {
let _ = CloseHandle(token);
return false;
}
let mut buf = vec![0u8; len as usize];
let ok = GetTokenInformation(
token,
TokenUser,
Some(buf.as_mut_ptr() as *mut _),
len,
&mut len,
)
.is_ok();
let _ = CloseHandle(token);
if !ok {
return false;
}
let tu = &*(buf.as_ptr() as *const TOKEN_USER);
// The well-known LocalSystem SID is S-1-5-18.
is_local_system_sid(tu.User.Sid)
}
}
/// True iff `sid` is S-1-5-18 (LocalSystem).
unsafe fn is_local_system_sid(sid: windows::Win32::Security::PSID) -> bool {
use windows::Win32::Security::{
GetSidIdentifierAuthority, GetSidSubAuthority, GetSidSubAuthorityCount, IsValidSid,
};
if !IsValidSid(sid).as_bool() {
return false;
}
let auth = GetSidIdentifierAuthority(sid);
if auth.is_null() {
return false;
}
// NT Authority = {0,0,0,0,0,5}.
let a = (*auth).Value;
if a != [0, 0, 0, 0, 0, 5] {
return false;
}
let count = *GetSidSubAuthorityCount(sid);
if count != 1 {
return false;
}
*GetSidSubAuthority(sid, 0) == 18 // SECURITY_LOCAL_SYSTEM_RID
}
+200
View File
@@ -1968,6 +1968,26 @@ fn virtual_stream(
probe_rx: std::sync::mpsc::Receiver<ProbeRequest>,
probe_result_tx: tokio::sync::mpsc::UnboundedSender<ProbeResult>,
) -> Result<()> {
// Windows two-process secure-desktop path: when the host runs as SYSTEM (required for the secure
// desktop + SendInput), WGC can't activate in-process, so we capture the normal desktop via a
// helper spawned in the user session and relay its AUs. (Single-process WGC/DDA is used as the
// user, and stays the path on Linux.) See docs/windows-secure-desktop.md.
#[cfg(target_os = "windows")]
if should_use_helper() {
return virtual_stream_relay(
session,
mode,
seconds,
stop,
reconfig,
keyframe,
compositor,
bitrate_kbps,
bit_depth,
probe_rx,
probe_result_tx,
);
}
tracing::info!(
compositor = compositor.id(),
?mode,
@@ -2178,6 +2198,186 @@ fn virtual_stream(
Ok(())
}
/// Should this host take the two-process (SYSTEM host + user-session WGC helper) path? Yes when it's
/// running as SYSTEM — the only account that can capture the secure desktop + drive SendInput on it,
/// and the account under which in-process WGC won't activate. `PUNKTFUNK_FORCE_HELPER` forces it on
/// (for testing the relay as a normal user); `PUNKTFUNK_NO_HELPER` forces it off.
#[cfg(target_os = "windows")]
fn should_use_helper() -> bool {
if std::env::var_os("PUNKTFUNK_NO_HELPER").is_some() {
return false;
}
std::env::var_os("PUNKTFUNK_FORCE_HELPER").is_some()
|| crate::capture::wgc_relay::running_as_system()
}
/// Windows two-process video stream: the SYSTEM host creates the SudoVDA virtual output (and holds
/// its keepalive = the sole topology/isolation owner), spawns the WGC helper in the user session to
/// capture+encode it, and relays the helper's AUs onto the QUIC data plane via the same send thread
/// as the single-process path. Reconfigure rebuilds the output + re-spawns the helper at the new
/// mode; keyframe requests are forwarded to the helper's encoder over its control channel.
///
/// Step 4 (this function): the normal-desktop relay. Step 5 adds the DesktopWatcher-driven mux that
/// switches to the host's own DDA encoder on the secure (Winlogon) desktop.
#[cfg(target_os = "windows")]
#[allow(clippy::too_many_arguments)]
fn virtual_stream_relay(
session: Session,
mode: punktfunk_core::Mode,
seconds: u32,
stop: Arc<AtomicBool>,
reconfig: &std::sync::mpsc::Receiver<punktfunk_core::Mode>,
keyframe: &std::sync::mpsc::Receiver<()>,
compositor: crate::vdisplay::Compositor,
bitrate_kbps: u32,
bit_depth: u8,
probe_rx: std::sync::mpsc::Receiver<ProbeRequest>,
probe_result_tx: tokio::sync::mpsc::UnboundedSender<ProbeResult>,
) -> Result<()> {
use crate::capture::wgc_relay::HelperRelay;
tracing::info!(
?mode,
bitrate_kbps,
bit_depth,
"punktfunk/1 two-process stream (SYSTEM host + user-session WGC helper)"
);
let mut vd = crate::vdisplay::open(compositor)?;
// Create the SudoVDA output + spawn a helper capturing it by GDI name. Returns the keepalive
// (held for the output's life — the sole isolation owner) and the running relay.
type Built = (Box<dyn Send>, HelperRelay);
let build = |vd: &mut Box<dyn crate::vdisplay::VirtualDisplay>,
mode: punktfunk_core::Mode|
-> Result<Built> {
let vout = vd.create(mode).context("create virtual output")?;
let effective_hz = vout
.preferred_mode
.map(|(_, _, hz)| hz)
.filter(|&hz| hz > 0)
.unwrap_or(mode.refresh_hz);
let target = vout.win_capture.clone().ok_or_else(|| {
anyhow!("SudoVDA target not yet an active display (needs a WDDM GPU to activate it)")
})?;
let relay = HelperRelay::spawn(
&target,
(mode.width, mode.height, effective_hz),
bitrate_kbps,
bit_depth,
)
.context("spawn WGC helper")?;
Ok((vout.keepalive, relay))
};
let (mut _keepalive, mut relay) = build(&mut vd, mode)?;
let perf = std::env::var("PUNKTFUNK_PERF").is_ok();
let burst_cap = std::env::var("PUNKTFUNK_PACE_BURST_KB")
.ok()
.and_then(|s| s.parse::<usize>().ok())
.unwrap_or(128)
* 1024;
// Same encode|send split as the single-process path: this thread relays AUs, a dedicated send
// thread owns the Session and does FEC+seal+paced-send.
let (frame_tx, frame_rx) = std::sync::mpsc::sync_channel::<FrameMsg>(3);
let send_thread = std::thread::Builder::new()
.name("punktfunk-send".into())
.spawn({
let stop = stop.clone();
move || {
send_loop(
session,
frame_rx,
probe_rx,
probe_result_tx,
stop,
perf,
burst_cap,
)
}
})
.context("spawn send thread")?;
let mut interval = std::time::Duration::from_secs_f64(1.0 / mode.refresh_hz.max(1) as f64);
let deadline = std::time::Instant::now() + std::time::Duration::from_secs(seconds as u64);
let mut sent: u64 = 0;
'outer: while !stop.load(Ordering::SeqCst) && std::time::Instant::now() < deadline {
// Mode switch: rebuild the output + re-spawn the helper at the new mode (drop the old relay +
// keepalive only after the new pair is up, so a failed rebuild keeps the current stream).
let mut want = None;
while let Ok(m) = reconfig.try_recv() {
want = Some(m);
}
if let Some(new_mode) = want {
tracing::info!(?new_mode, "two-process: rebuilding for mode switch");
match build(&mut vd, new_mode) {
Ok((ka, rl)) => {
relay = rl; // drops the old relay (kills old helper) ...
_keepalive = ka; // ... then releases the old output
interval =
std::time::Duration::from_secs_f64(1.0 / new_mode.refresh_hz.max(1) as f64);
}
Err(e) => {
tracing::error!(error = %format!("{e:#}"), ?new_mode,
"two-process mode-switch rebuild failed — staying on the current mode");
}
}
}
// Forward client decode-recovery keyframe requests to the helper's encoder.
let mut want_kf = false;
while keyframe.try_recv().is_ok() {
want_kf = true;
}
if want_kf {
tracing::debug!("two-process: forwarding keyframe request to helper");
relay.request_keyframe();
}
// Pull the next relayed AU. A timeout means the helper stalled (or is mid-respawn); loop so
// reconfig/keyframe/stop still get serviced. Disconnected means the helper exited — end the
// stream (step 6 adds a relaunch watchdog; for now a dead helper ends the session).
let au = match relay.recv_timeout(std::time::Duration::from_millis(500)) {
Ok(au) => au,
Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {
if stop.load(Ordering::SeqCst) {
break;
}
tracing::warn!("two-process: no AU from helper within 500ms");
continue;
}
Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
tracing::error!("two-process: WGC helper exited — ending stream");
break;
}
};
let flags = if au.keyframe {
(FLAG_PIC | FLAG_SOF) as u32
} else {
FLAG_PIC as u32
};
// The helper's pts_ns is on this machine's monotonic clock (same `now_ns()` source), so it is
// directly usable as the capture timestamp. encode_us = pipe-relay latency from capture.
let capture_ns = au.pts_ns;
let encode_us = (now_ns().saturating_sub(capture_ns) / 1000) as u32;
let msg = FrameMsg {
data: au.data,
capture_ns,
flags,
deadline: std::time::Instant::now() + interval,
encode_us,
};
if frame_tx.send(msg).is_err() {
break 'outer; // send thread gone
}
sent += 1;
}
drop(frame_tx);
let _ = send_thread.join();
tracing::info!(sent, "punktfunk/1 two-process stream complete");
Ok(())
}
/// One mode's capture/encode pipeline: (capturer, encoder, first frame, frame interval).
/// Dropping the capturer tears down the PipeWire stream and the virtual output with it.
type Pipeline = (
+1
View File
@@ -223,6 +223,7 @@ fn real_main() -> Result<()> {
bitrate_kbps: get("--bitrate")
.and_then(|s| s.parse().ok())
.unwrap_or(20000),
bit_depth: get("--bit-depth").and_then(|s| s.parse().ok()).unwrap_or(8),
})
}
Some("-h") | Some("--help") | Some("help") | None => {
+38 -3
View File
@@ -15,7 +15,9 @@
use crate::capture::{dxgi::WinCaptureTarget, wgc::WgcCapturer, Capturer};
use crate::encode::{self, Codec};
use anyhow::{Context, Result};
use std::io::Write;
use std::io::{Read, Write};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
pub struct HelperOptions {
pub target_id: u32,
@@ -24,11 +26,18 @@ pub struct HelperOptions {
pub height: u32,
pub fps: u32,
pub bitrate_kbps: u32,
/// Negotiated encode bit depth (8, or 10 = HEVC Main10). HDR auto-upgrades to 10 from the
/// captured frame's `Rgb10a2` format regardless.
pub bit_depth: u8,
}
/// AU framing magic + version, so the host can resync / detect a helper crash on its stdout stream.
const AU_MAGIC: u32 = 0x5046_4155; // "PFAU"
/// Control byte the host writes on our stdin to force the next frame to be an IDR. Must match
/// `wgc_relay::CTL_KEYFRAME`.
const CTL_KEYFRAME: u8 = 0x01;
pub fn run(opts: HelperOptions) -> Result<()> {
tracing::info!(
target_id = opts.target_id,
@@ -59,11 +68,34 @@ pub fn run(opts: HelperOptions) -> Result<()> {
h,
opts.fps,
opts.bitrate_kbps as u64 * 1000,
false, // not cuda
8, // bit depth: HDR auto-upgrades to Main10 from the Rgb10a2 frame
false, // not cuda
opts.bit_depth, // 8, or 10 = Main10 (HDR auto-upgrades from the Rgb10a2 frame regardless)
)
.context("open NVENC")?;
// Control channel: the host writes a single byte on our stdin to force an IDR (client decode
// recovery), mirroring `enc.request_keyframe()` in the single-process path. A reader thread sets
// a flag the encode loop checks; stdin EOF (host gone) just stops the thread.
let kf = Arc::new(AtomicBool::new(false));
{
let kf = kf.clone();
std::thread::Builder::new()
.name("wgc-helper-ctl".into())
.spawn(move || {
let mut stdin = std::io::stdin();
let mut byte = [0u8; 1];
while let Ok(n) = stdin.read(&mut byte) {
if n == 0 {
break; // host closed our stdin
}
if byte[0] == CTL_KEYFRAME {
kf.store(true, Ordering::Relaxed);
}
}
})
.ok();
}
// Binary stdout — lock it once + write framed AUs. A short write / broken pipe means the host
// (parent) went away → exit cleanly so the host's relaunch watchdog can respawn us.
let stdout = std::io::stdout();
@@ -71,6 +103,9 @@ pub fn run(opts: HelperOptions) -> Result<()> {
let mut frame = first;
loop {
if kf.swap(false, Ordering::Relaxed) {
enc.request_keyframe();
}
enc.submit(&frame).context("encoder submit")?;
while let Some(au) = enc.poll().context("encoder poll")? {
if write_au(&mut out, &au).is_err() {