fix(host/encode): negotiate the cursor around what the encoder can blend

EncoderCaps::blends_cursor's contract said the HOST must fall back to
capturer-side compositing when a cursor-as-metadata session lands on an
encoder that can't composite — but that host half was never built: open_video
warned and the session streamed WITHOUT a pointer (confirmed on the VAAPI
dmabuf and libav-NVENC CUDA paths; latent on vulkan RGB-direct/native-NV12).
The negotiation is now caps-aware, ahead of capture, on both planes:

* pf-encode grows cursor_blend_capable() — the pre-open dispatch mirror
  (sibling of linux_native_nv12_ok) answering whether the resolved backend
  composites frame.cursor; its pure core is test-pinned arm by arm.
* Native plane: handshake::cursor_forward grants the cursor channel only
  where the resolved backend can blend (the capture-mouse flip makes the host
  draw the pointer on demand); denied sessions keep the pre-channel path —
  the compositor EMBEDS the pointer, never cursorless, never doubled. The
  Welcome's HOST_CAP_CURSOR bit is computed once and read back at both
  session-wiring sites instead of recomputed. SessionPlan::output_format
  additionally keeps every cursor-blend session off producer-native NV12 (the
  arm with no CSC to fold a cursor into), and vulkan RGB-direct now yields to
  a cursor-blend session even when pinned (EFC cannot composite; the open
  logs the override). Windows plans cursor_blend=false via the new shared
  cursor_blend_for() rule — the IDD capturer composites the pointer itself,
  and asking the encoder anyway fired the blends-cursor warn spuriously on
  every cursor-channel session.
* GameStream plane: the hardcoded cursor_blend=true is gone. The portal
  source asks for cursor-as-metadata only when the resolved backend blends,
  otherwise negotiates an Embedded pointer (choose_cursor_mode's new ladder);
  the capturer pool now also keys on that mode. The virtual-output source
  passes false — its capture embeds the pointer where it can.

The per-arm warns in vulkan_video (RGB-direct, native-NV12) are now
structurally unreachable and removed. open_video's post-open check stays as
the single backstop for what planning cannot see: a Vulkan-open falling back
to VAAPI mid-session, and the gamescope residual (no embedded mode exists
there, so a never-blending backend — H.264-on-AMD VAAPI, software — still
streams cursorless; fixing that needs a compositing stage, deliberately not
built in this pass). Zero-copy is preserved throughout — every fallback is a
capture-negotiation change, never a readback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/punktfunk-host/src/capture.rs

@@ -66,8 +66,14 @@ fn zero_copy_policy(
 /// Open a live capturer for a client-sized monitor via the xdg ScreenCast portal. `want_hdr`
 /// offers the GNOME 50+ 10-bit PQ/BT.2020 formats (pass it only when the session negotiated HDR
 /// AND the mirrored monitor is in HDR mode — see [`pf_capture::gnome_hdr_monitor_active`]).
+/// `want_metadata_cursor` asks for cursor-as-metadata — pass it only when the session's encode
+/// backend composites `CapturedFrame::cursor` (`encode::cursor_blend_capable`); otherwise the
+/// portal embeds the pointer, so no backend × cursor-mode combination streams cursorless.
 #[cfg(target_os = "linux")]
-pub fn open_portal_monitor(want_hdr: bool) -> Result<Box<dyn Capturer>> {
+pub fn open_portal_monitor(
+    want_hdr: bool,
+    want_metadata_cursor: bool,
+) -> Result<Box<dyn Capturer>> {
     // On RemoteDesktop-capable desktops (KWin/GNOME) anchor ScreenCast to a RemoteDesktop
     // session so it inherits that grant headlessly; wlroots/Sway has no RemoteDesktop portal,
     // so use a plain ScreenCast session there.
@@ -76,11 +82,19 @@ pub fn open_portal_monitor(want_hdr: bool) -> Result<Box<dyn Capturer>> {
     // passthrough is virtual-output-only; the global encoder-pref lever still applies inside.
     // Native NV12 stays off too: the mirror path doesn't resolve the codec here, and the desktop
     // compositors it mirrors (GNOME/KWin) don't produce NV12 anyway.
-    pf_capture::open_portal_monitor(anchored, want_hdr, zero_copy_policy(false, false))
+    pf_capture::open_portal_monitor(
+        anchored,
+        want_hdr,
+        want_metadata_cursor,
+        zero_copy_policy(false, false),
+    )
 }
 
 #[cfg(not(target_os = "linux"))]
-pub fn open_portal_monitor(_want_hdr: bool) -> Result<Box<dyn Capturer>> {
+pub fn open_portal_monitor(
+    _want_hdr: bool,
+    _want_metadata_cursor: bool,
+) -> Result<Box<dyn Capturer>> {
     anyhow::bail!("portal capture requires Linux (xdg-desktop-portal + PipeWire)")
 }
 

crates/punktfunk-host/src/gamestream/stream.rs

@@ -33,10 +33,14 @@ pub struct StreamConfig {
     pub hdr: bool,
 }
 
+/// A pooled capturer plus the two PipeWire-negotiation-time properties reuse must match on —
+/// its HDR-ness and its metadata-cursor mode; a mismatch on either needs a fresh screencast
+/// session (see `AppState::video_cap`).
+pub type PooledCapturer = (Box<dyn Capturer>, bool, bool);
+
 /// Slot for the persistent screen capturer, shared with the control plane and reused across
-/// streams so a reconnect doesn't open a second (conflicting) screencast session. The `bool` is
-/// the pooled capturer's HDR-ness (see `AppState::video_cap`).
-pub type CapturerSlot = Arc<std::sync::Mutex<Option<(Box<dyn Capturer>, bool)>>>;
+/// streams so a reconnect doesn't open a second (conflicting) screencast session.
+pub type CapturerSlot = Arc<std::sync::Mutex<Option<PooledCapturer>>>;
 
 /// A pending client reference-frame-invalidation range (lost `firstFrame..=lastFrame`), set by the
 /// control plane and drained by the video thread (see [`AppState::rfi_range`](super::AppState)).
@@ -136,7 +140,7 @@ fn run(
     running: &Arc<AtomicBool>,
     force_idr: &AtomicBool,
     rfi_range: &std::sync::Mutex<Option<(i64, i64)>>,
-    video_cap: &std::sync::Mutex<Option<(Box<dyn Capturer>, bool)>>,
+    video_cap: &std::sync::Mutex<Option<PooledCapturer>>,
     // Shared stats recorder for the web-console capture/graph. Threaded into `stream_body` (the
     // encode loop); per-frame sample emission is wired by a later pass.
     stats: &Arc<crate::stats_recorder::StatsRecorder>,
@@ -250,6 +254,12 @@ fn run(
         return stream_body(
             &mut capturer,
             Some(&rebuild),
+            // The virtual-output source never selects cursor-as-metadata (`set_hw_cursor` is
+            // never called → the compositor EMBEDS the pointer where it can), so the encoder
+            // is handed nothing to composite. gamescope remains the pointerless residual —
+            // its capture carries no cursor either way (the native plane's XFixes source is
+            // not wired on this plane).
+            false,
             &sock,
             cfg,
             running,
@@ -266,13 +276,34 @@ fn run(
     // pooled capturer's HDR-ness matching this stream's negotiated `cfg.hdr` — the depth is a
     // PipeWire-negotiation-time property of the screencast session, so an HDR↔SDR change needs a
     // fresh session (same pattern as the audio capturer's channel-count gate).
+    // Cursor-as-metadata only where the encode backend this session resolves to composites
+    // `frame.cursor` (the caps-aware negotiation — mirror of the native plane's); otherwise ask
+    // the portal to EMBED the pointer so no backend × cursor-mode combination streams
+    // cursorless. Synthetic frames carry no pointer either way.
+    let metadata_cursor = {
+        #[cfg(target_os = "linux")]
+        {
+            // Same CUDA-payload prediction SessionPlan/`handshake::cursor_forward` make:
+            // the NVIDIA resolution plus the zero-copy master switch.
+            let cuda_planned =
+                !crate::encode::linux_zero_copy_is_vaapi() && crate::zerocopy::enabled();
+            crate::encode::cursor_blend_capable(cfg.codec, cuda_planned, cfg.hdr)
+        }
+        #[cfg(not(target_os = "linux"))]
+        false
+    };
     let pooled = match video_cap.lock().unwrap().take() {
-        Some((c, was_hdr)) if was_hdr == cfg.hdr => Some(c),
-        Some((c, was_hdr)) => {
+        Some((c, was_hdr, was_meta)) if was_hdr == cfg.hdr && was_meta == metadata_cursor => {
+            Some(c)
+        }
+        Some((c, was_hdr, was_meta)) => {
             tracing::info!(
                 was_hdr,
                 want_hdr = cfg.hdr,
-                "video source: pooled capturer depth mismatch — opening a fresh screencast session"
+                was_metadata_cursor = was_meta,
+                want_metadata_cursor = metadata_cursor,
+                "video source: pooled capturer depth/cursor-mode mismatch — opening a fresh \
+                 screencast session"
             );
             drop(c);
             None
@@ -285,8 +316,13 @@ fn run(
             c
         }
         None if pf_host_config::config().video_source.as_deref() == Some("portal") => {
-            tracing::info!(hdr = cfg.hdr, "video source: portal desktop capture");
-            capture::open_portal_monitor(cfg.hdr).context("open portal capturer")?
+            tracing::info!(
+                hdr = cfg.hdr,
+                metadata_cursor,
+                "video source: portal desktop capture"
+            );
+            capture::open_portal_monitor(cfg.hdr, metadata_cursor)
+                .context("open portal capturer")?
         }
         None => {
             tracing::info!("video source: synthetic test pattern");
@@ -298,6 +334,7 @@ fn run(
     let result = stream_body(
         &mut capturer,
         None,
+        metadata_cursor,
         &sock,
         cfg,
         running,
@@ -308,7 +345,7 @@ fn run(
         on_lost,
     );
     capturer.set_active(false);
-    *video_cap.lock().unwrap() = Some((capturer, cfg.hdr));
+    *video_cap.lock().unwrap() = Some((capturer, cfg.hdr, metadata_cursor));
     result
 }
 
@@ -646,6 +683,10 @@ fn stream_body(
     // Re-open the video source on capture loss (virtual-display path → follow a Desktop<->Game switch);
     // `None` for the portal/synthetic source, which has nothing to re-detect (propagate the error).
     rebuild: Option<&dyn Fn() -> Result<Box<dyn Capturer>>>,
+    // The capture hands the encoder cursor bitmaps to composite (cursor-as-metadata negotiated
+    // because the resolved backend blends — see the callers). `false` = the pointer is embedded
+    // in the pixels (or absent), so the encoder is asked to composite nothing.
+    cursor_blend: bool,
     sock: &UdpSocket,
     cfg: StreamConfig,
     running: &Arc<AtomicBool>,
@@ -681,9 +722,9 @@ fn stream_body(
         // GameStream/Moonlight stays 4:2:0 — stock Moonlight clients can't decode 4:4:4, and the
         // Windows IDD-push capturer can't yet deliver full-chroma frames. 4:4:4 is punktfunk/1-native only.
         encode::ChromaFormat::Yuv420,
-        // Desktop monitor capture negotiates cursor-as-metadata where available — the encoder
-        // may be handed cursor bitmaps to composite.
-        true,
+        // True only when THIS session's capture negotiated cursor-as-metadata — which the
+        // callers grant only where the resolved backend composites (`cursor_blend_capable`).
+        cursor_blend,
     )
     .context("open video encoder for stream")?;
     // Tell the encoder how deep the capturer lets it pipeline. Without this an in-place backend
@@ -855,7 +896,7 @@ fn stream_body(
                     frame.is_cuda(),
                     gs_bit_depth(frame.format),
                     encode::ChromaFormat::Yuv420, // GameStream stays 4:2:0
-                    true,                         // metadata-cursor capture — see the first open
+                    cursor_blend,                 // same capture cursor mode — see the first open
                 )
                 .context("reopen encoder after rebuild")?;
                 // A rebuilt encoder starts unconfigured — same reason as the first open above.

crates/punktfunk-host/src/native.rs

@@ -1012,9 +1012,10 @@ async fn serve_session(
     // just never fires then.
     let (cursor_shape_tx, cursor_shape_rx) =
         tokio::sync::mpsc::unbounded_channel::<punktfunk_core::quic::CursorShape>();
-    // Negotiated cursor forwarding: MUST match the HOST_CAP_CURSOR bit the Welcome advertised
-    // (handshake::cursor_forward is the single predicate both read).
-    let cursor_forward = handshake::cursor_forward(hello.client_caps, compositor);
+    // Negotiated cursor forwarding: the HOST_CAP_CURSOR bit the Welcome advertised, read back
+    // rather than recomputed (`handshake::cursor_forward` computed it once, with the encoder
+    // blend-capability gate — re-running it here could drift, and would re-probe).
+    let cursor_forward = welcome.host_caps & punktfunk_core::quic::HOST_CAP_CURSOR != 0;
     // Who renders the pointer RIGHT NOW (client `CursorRenderMode`, flipped live by the mouse-
     // model chord): `true` = client draws (exclude + forward), `false` = host composites (the
     // capture model). Starts true — the pre-message behavior for cap sessions. Control task

crates/punktfunk-host/src/native/handshake.rs

@@ -12,31 +12,46 @@ use super::*;
 /// the client asked ([`CLIENT_CAP_CURSOR`](punktfunk_core::quic::CLIENT_CAP_CURSOR)) AND the
 /// capture path can deliver cursor metadata separately from the frame — the Linux portal
 /// `SPA_META_Cursor` path (not gamescope, whose capture paints no cursor at all), or Windows
-/// with a proto-v5 pf-vdisplay driver (the IddCx hardware-cursor channel, M2c). THE single
-/// predicate: the Welcome's `HOST_CAP_CURSOR` bit and the session's forwarding/blend-off
-/// wiring both read it, so they can never disagree.
+/// with a proto-v5 pf-vdisplay driver (the IddCx hardware-cursor channel, M2c) — AND, on
+/// Linux, the encode backend this session resolves to can composite the pointer on demand
+/// (`encode::cursor_blend_capable`): the channel's capture-mouse flip (`CursorRenderMode`,
+/// `client_draws = false`) makes the HOST draw the pointer, and on Linux the encoder is that
+/// compositing stage — granting the channel over a backend that can't blend (libav
+/// VAAPI/NVENC, software) shipped a cursorless stream on every capture-mode flip. Denied, the
+/// session keeps the pre-channel path: the compositor EMBEDS the pointer and the client never
+/// draws — never cursorless, never doubled. THE single predicate: the Welcome's
+/// `HOST_CAP_CURSOR` bit is computed from it, and the session wiring reads that bit back.
 pub(super) fn cursor_forward(
     client_caps: u8,
     compositor: Option<crate::vdisplay::Compositor>,
+    codec: crate::encode::Codec,
+    bit_depth: u8,
 ) -> bool {
     if client_caps & punktfunk_core::quic::CLIENT_CAP_CURSOR == 0 {
         return false;
     }
     #[cfg(target_os = "linux")]
     {
+        // CUDA-payload prediction — the same one `SessionPlan` makes: the NVIDIA resolution
+        // plus the zero-copy master switch. It decides direct-SDK NVENC (blends) vs libav
+        // NVENC (doesn't) inside the capability mirror.
+        let cuda_planned = !crate::encode::linux_zero_copy_is_vaapi() && crate::zerocopy::enabled();
         compositor.is_some_and(|c| c != crate::vdisplay::Compositor::Gamescope)
+            && crate::encode::cursor_blend_capable(codec, cuda_planned, bit_depth == 10)
     }
     #[cfg(target_os = "windows")]
     {
         // Windows (M2c): the pf-vdisplay driver must speak the v5 hardware-cursor channel —
         // DWM composites the pointer into the IDD frame otherwise, and forwarding a second
-        // copy would double it. The probe latches by opening the control device once.
-        let _ = compositor;
+        // copy would double it. The probe latches by opening the control device once. The
+        // encoder is deliberately NOT consulted: the IDD capturer itself composites on the
+        // capture-mouse flip (`set_cursor_forward`), so no Windows encode backend blends.
+        let _ = (compositor, codec, bit_depth);
         crate::vdisplay::manager::hw_cursor_capable()
     }
     #[cfg(not(any(target_os = "linux", target_os = "windows")))]
     {
-        let _ = compositor;
+        let _ = (compositor, codec, bit_depth);
         false
     }
 }
@@ -488,9 +503,10 @@ pub(super) async fn negotiate(
                 0
             }
             // Cursor channel granted (client asked + this capture path can deliver cursor
-            // metadata out of the frame) — the client turns its local renderer on ONLY when
-            // it sees this bit, and serve_session wires forwarding from the same predicate.
-            | if cursor_forward(hello.client_caps, compositor) {
+            // metadata out of the frame + the resolved encoder can composite on the
+            // capture-mouse flip) — the client turns its local renderer on ONLY when it sees
+            // this bit, and serve_session wires forwarding by reading the bit back.
+            | if cursor_forward(hello.client_caps, compositor, codec, bit_depth) {
                 punktfunk_core::quic::HOST_CAP_CURSOR
             } else {
                 0
@@ -536,9 +552,9 @@ pub(super) async fn negotiate(
             let (ctx_tx, ctx_rx) = std::sync::mpsc::sync_channel::<SessionContext>(1);
             let client_identity = endpoint::peer_fingerprint(conn);
             let client_hdr = hello.display_hdr;
-            // Same predicate the Welcome's HOST_CAP_CURSOR bit used — the prepared display and
-            // the session wiring must agree with what we just advertised.
-            let cursor_fw = cursor_forward(hello.client_caps, Some(comp));
+            // The bit the Welcome just advertised — read back rather than recomputed, so the
+            // prepared display and the session wiring cannot disagree with it.
+            let cursor_fw = welcome.host_caps & punktfunk_core::quic::HOST_CAP_CURSOR != 0;
             let (mode, shard_payload) = (hello.mode, welcome.shard_payload);
             let trace = bringup.clone();
             std::thread::Builder::new()

crates/punktfunk-host/src/native/stream.rs

@@ -1022,8 +1022,13 @@ pub(super) fn virtual_stream(ctx: SessionContext, prepared: Option<PreparedDispl
         // pointer compositor-EMBEDDED (`vd.set_hw_cursor(false)` → no cursor metadata, nothing to
         // blend), keeping the zero-cost pre-channel path. gamescope is the exception (Phase C):
         // it can't embed the pointer, so the host ALWAYS composites the XFixes-sourced cursor —
-        // the blend must be built for every gamescope session.
-        ctx.compositor == pf_vdisplay::Compositor::Gamescope || ctx.cursor_forward,
+        // the blend must be built for every gamescope session. (`cursor_forward` is already
+        // blend-gated: `handshake::cursor_forward` grants the channel only where
+        // `encode::cursor_blend_capable` says the resolved backend composites.)
+        crate::session_plan::cursor_blend_for(
+            ctx.cursor_forward,
+            ctx.compositor == pf_vdisplay::Compositor::Gamescope,
+        ),
         ctx.cursor_forward,
     );
     // gamescope: the XFixes cursor source feeds the always-on composite (Phase C). Set after
@@ -2098,8 +2103,10 @@ pub(super) fn virtual_stream(ctx: SessionContext, prepared: Option<PreparedDispl
                                         // capture-mode channel); a switch AWAY restores the prior
                                         // gating. `plan` is `Copy` — this is the value the rebuild
                                         // (and its `build_pipeline` attach) reads.
-                                        plan.cursor_blend = plan.cursor_forward
-                                            || c == crate::vdisplay::Compositor::Gamescope;
+                                        plan.cursor_blend = crate::session_plan::cursor_blend_for(
+                                            plan.cursor_forward,
+                                            c == crate::vdisplay::Compositor::Gamescope,
+                                        );
                                         plan.gamescope_cursor =
                                             c == crate::vdisplay::Compositor::Gamescope;
                                         gamescope_composite =
@@ -2987,7 +2994,10 @@ pub(super) fn prepare_display(
         // non-gamescope sessions get the pointer compositor-EMBEDDED, nothing to blend; the
         // mid-stream `CursorRenderMode` flip strips/keeps `frame.cursor` per tick for channel
         // sessions). gamescope (Phase C) can't embed → always composites the XFixes cursor.
-        compositor == pf_vdisplay::Compositor::Gamescope || cursor_forward,
+        crate::session_plan::cursor_blend_for(
+            cursor_forward,
+            compositor == pf_vdisplay::Compositor::Gamescope,
+        ),
         cursor_forward,
     );
     plan.gamescope_cursor = compositor == pf_vdisplay::Compositor::Gamescope;

crates/punktfunk-host/src/session_plan.rs

@@ -104,9 +104,13 @@ pub struct SessionPlan {
     /// AUs stay shard-aligned across mode/bitrate/stall rebuilds. `None` for the H.26x codecs.
     pub wire_chunk: Option<usize>,
     /// The session may hand the encoder cursor bitmaps to composite (cursor-as-metadata
-    /// captures — every non-gamescope compositor; gamescope embeds the pointer itself).
-    /// Encoders whose fast path cannot blend (the Vulkan EFC RGB-direct source) stay on their
-    /// blending path when this is set, so the pointer never silently vanishes from the stream.
+    /// captures). Set via [`cursor_blend_for`] — the single platform rule — so it is `true` only
+    /// where the ENCODER is the compositing stage (Linux cursor-forward and gamescope sessions);
+    /// Windows is always `false` (the IDD capturer composites the pointer itself). Encoders
+    /// whose fast path cannot blend (the Vulkan EFC RGB-direct source, native NV12) stay off
+    /// those shapes when this is set — see [`Self::output_format`] and
+    /// `encode::cursor_blend_capable`, the pre-open mirror that gates the cursor channel — so
+    /// the pointer never silently vanishes from the stream.
     pub cursor_blend: bool,
     /// The session negotiated the cursor-forward channel (M2/M2c): the client draws the pointer
     /// locally, so `cursor_blend` is off AND (on Windows) the capturer sets the driver's
@@ -198,13 +202,15 @@ impl SessionPlan {
             // Producer-native NV12 (gamescope) is consumable only by the Linux Vulkan Video
             // backend — resolved HERE from the plan's codec so the capturer never reaches back
             // into encode (the same one-way edge as `gpu` above). BUT the native-NV12 encode path
-            // has no CSC stage to fold the cursor into (it assumes gamescope embeds its pointer,
-            // which it does NOT into the PipeWire node) — so a gamescope-cursor session (Phase C)
-            // must capture RGB instead, routing to the compute-CSC / VkSlotBlend blend that draws
-            // `frame.cursor`. Costs the RGB→NV12 CSC we'd otherwise skip; the native-NV12 cursor
-            // blend is the perf-preserving follow-up.
+            // has no CSC stage to fold the cursor into — so ANY cursor-compositing session
+            // (gamescope Phase C, whose XFixes pointer is absent from the PipeWire node, AND a
+            // cursor-forward session, whose capture-mouse flip needs the host composite on
+            // demand) must capture RGB instead, routing to the compute-CSC / VkSlotBlend blend
+            // that draws `frame.cursor`. Costs the RGB→NV12 CSC we'd otherwise skip; the
+            // native-NV12 cursor blend is the perf-preserving follow-up. (`cursor_blend`
+            // subsumes `gamescope_cursor` — see [`cursor_blend_for`].)
             #[cfg(target_os = "linux")]
-            nv12_native: crate::encode::linux_native_nv12_ok(self.codec) && !self.gamescope_cursor,
+            nv12_native: crate::encode::linux_native_nv12_ok(self.codec) && !self.cursor_blend,
             #[cfg(not(target_os = "linux"))]
             nv12_native: false,
         }
@@ -217,6 +223,26 @@ pub(crate) fn resolve_topology() -> SessionTopology {
     SessionTopology::SingleProcess
 }
 
+/// THE rule for [`SessionPlan::cursor_blend`], shared by every resolve caller (initial plan and
+/// the mid-stream compositor re-gate) so they can't drift:
+/// * **Linux**: the encoder is the compositing stage — blend for a cursor-forward session (the
+///   capture-mouse flip needs the host composite on demand) and for gamescope (its capture
+///   carries no pointer at all; the XFixes-sourced cursor must be drawn into the video).
+/// * **Windows**: never — the IDD capturer composites the pointer itself (`cursor_blend.rs` /
+///   DWM), and no Windows encode backend reads `frame.cursor`. Asking the encoder anyway made
+///   `open_video`'s blends-cursor backstop fire spuriously on every cursor-channel session.
+pub(crate) fn cursor_blend_for(cursor_forward: bool, gamescope: bool) -> bool {
+    #[cfg(target_os = "windows")]
+    {
+        let _ = (cursor_forward, gamescope);
+        false
+    }
+    #[cfg(not(target_os = "windows"))]
+    {
+        cursor_forward || gamescope
+    }
+}
+
 #[cfg(target_os = "windows")]
 fn resolve_encoder() -> EncoderBackend {
     match crate::encode::windows_resolved_backend() {

crates/punktfunk-host/src/spike.rs

@@ -94,7 +94,9 @@ pub fn run(opts: Options) -> Result<()> {
                 want_hdr,
                 "spike source: xdg ScreenCast portal (live monitor)"
             );
-            capture::open_portal_monitor(want_hdr).context("open portal capturer")?
+            // Embedded cursor: the spike passes `cursor_blend = false` to its encoder open, so
+            // a metadata pointer would be composited by nothing.
+            capture::open_portal_monitor(want_hdr, false).context("open portal capturer")?
         }
         Source::KwinVirtual => {
             let compositor = crate::vdisplay::detect().unwrap_or(crate::vdisplay::Compositor::Kwin);