feat: Chromecast + AirPlay 2 casting

Makefile

@@ -18,7 +18,7 @@ SHELL_INSTALL_DIR=$(DATA_DIR)/quickshell/dms
 ASSETS_DIR=assets
 APPLICATIONS_DIR=$(DATA_DIR)/applications
 
-.PHONY: all build clean lint-qml install install-bin install-shell install-completions install-systemd install-icon install-desktop uninstall uninstall-bin uninstall-shell uninstall-completions uninstall-systemd uninstall-icon uninstall-desktop help
+.PHONY: all build cast-helper clean lint-qml install install-bin install-cast-helper install-shell install-completions install-systemd install-icon install-desktop uninstall uninstall-bin uninstall-shell uninstall-completions uninstall-systemd uninstall-icon uninstall-desktop help
 
 all: build
 
@@ -27,6 +27,11 @@ build:
 	@$(MAKE) -C $(CORE_DIR) build
 	@echo "Build complete"
 
+# Opt-in: builds the go-gst screen-capture helper for the cast screen-mirror
+# feature (needs CGO + GStreamer dev packages). The main dms build stays CGO-free.
+cast-helper:
+	@$(MAKE) -C $(CORE_DIR) cast-helper
+
 clean:
 	@echo "Cleaning build artifacts..."
 	@$(MAKE) -C $(CORE_DIR) clean
@@ -41,6 +46,10 @@ install-bin:
 	@install -D -m 755 $(BUILD_DIR)/$(BINARY_NAME) $(INSTALL_DIR)/$(BINARY_NAME)
 	@echo "Binary installed"
 
+# Install the cast helper alongside dms (dms locates it in the same directory).
+install-cast-helper:
+	@$(MAKE) -C $(CORE_DIR) install-cast-helper PREFIX=$(PREFIX)
+
 install-shell:
 	@echo "Installing shell files to $(SHELL_INSTALL_DIR)..."
 	@mkdir -p $(SHELL_INSTALL_DIR)

core/Makefile

@@ -1,7 +1,9 @@
 BINARY_NAME=dms
 BINARY_NAME_INSTALL=dankinstall
+CAST_HELPER=dms-cast-helper
 SOURCE_DIR=cmd/dms
 SOURCE_DIR_INSTALL=cmd/dankinstall
+SOURCE_DIR_CAST=cmd/dms-cast-helper
 BUILD_DIR=bin
 PREFIX ?= /usr/local
 INSTALL_DIR=$(PREFIX)/bin
@@ -22,7 +24,7 @@ BUILD_LDFLAGS=-ldflags='-s -w -X main.Version=$(VERSION) -X main.buildTime=$(BUI
 # Architecture to build for dist target (amd64, arm64, or all)
 ARCH ?= all
 
-.PHONY: all build dankinstall dist clean install install-all install-dankinstall uninstall uninstall-all uninstall-dankinstall install-config uninstall-config test fmt vet deps print-version help
+.PHONY: all build dankinstall cast-helper dist clean install install-all install-dankinstall install-cast-helper uninstall uninstall-all uninstall-dankinstall install-config uninstall-config test fmt vet deps print-version help
 
 # Default target
 all: build
@@ -40,6 +42,16 @@ dankinstall:
 	CGO_ENABLED=0 $(GO) build $(BUILD_LDFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME_INSTALL) ./$(SOURCE_DIR_INSTALL)
 	@echo "Build complete: $(BUILD_DIR)/$(BINARY_NAME_INSTALL)"
 
+# Build the go-gst screen-capture helper used by the cast screen-mirror feature.
+# Opt-in (not part of `make build`) because it needs CGO + GStreamer dev packages
+# (gstreamer-1.0, gst-plugins-base, plus plugins-good/bad/ugly + pipewire at
+# runtime). The main dms binary stays CGO-free and spawns this when present.
+cast-helper:
+	@echo "Building $(CAST_HELPER) (requires CGO + GStreamer dev)..."
+	@mkdir -p $(BUILD_DIR)
+	CGO_ENABLED=1 $(GO) build -tags casthelper -ldflags='-s -w' -o $(BUILD_DIR)/$(CAST_HELPER) ./$(SOURCE_DIR_CAST)
+	@echo "Build complete: $(BUILD_DIR)/$(CAST_HELPER)"
+
 # Build distro binaries for amd64 and arm64 (Linux only, no update/greeter support)
 dist:
 ifeq ($(ARCH),all)
@@ -68,6 +80,12 @@ install:
 	@install -D -m 755 $(BUILD_DIR)/$(BINARY_NAME) $(INSTALL_DIR)/$(BINARY_NAME)
 	@echo "Installation complete"
 
+# Install the cast helper next to dms (dms finds it via the same directory).
+install-cast-helper:
+	@echo "Installing $(CAST_HELPER) to $(INSTALL_DIR)..."
+	@install -D -m 755 $(BUILD_DIR)/$(CAST_HELPER) $(INSTALL_DIR)/$(CAST_HELPER)
+	@echo "Installation complete"
+
 install-all:
 	@echo "Installing $(BINARY_NAME) to $(INSTALL_DIR)..."
 	@install -D -m 755 $(BUILD_DIR)/$(BINARY_NAME) $(INSTALL_DIR)/$(BINARY_NAME)

core/cmd/dms-cast-helper/main.go

@@ -0,0 +1,167 @@
+//go:build casthelper
+
+// Command dms-cast-helper captures the screen with GStreamer (the go-gst
+// library — no gst-launch CLI) and either writes an HLS stream (for Chromecast)
+// or an H.264 byte-stream to stdout (for AirPlay/doubletake).
+//
+// The screen source is the xdg-desktop-portal PipeWire remote: the parent
+// negotiates the portal and passes the remote fd as fd 3 plus the node id via
+// -node. With -test the source is a synthetic pattern (no portal needed), which
+// makes the pipeline verifiable offline.
+//
+// Built only with CGO (it links GStreamer); the package has a no-cgo stub so
+// `CGO_ENABLED=0 go build ./...` over the core stays green.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/go-gst/go-gst/gst"
+	"github.com/go-gst/go-gst/gst/app"
+)
+
+const portalFD = 3 // the PipeWire remote fd the parent passes via ExtraFiles
+
+func main() {
+	mode := flag.String("mode", "h264", "output mode: h264 (stdout) | hls")
+	out := flag.String("out", "", "HLS output directory (mode=hls)")
+	node := flag.Int("node", 0, "PipeWire node id from the portal")
+	fps := flag.Int("fps", 30, "framerate")
+	bitrate := flag.Int("bitrate", 4147, "x264 bitrate kbps")
+	width := flag.Int("width", 1920, "scaled width")
+	height := flag.Int("height", 1080, "scaled height")
+	test := flag.Bool("test", false, "use a synthetic source instead of the portal (debug)")
+	flag.Parse()
+
+	gst.Init(nil)
+
+	desc, err := buildPipeline(*mode, *out, *node, *fps, *bitrate, *width, *height, *test)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "dms-cast-helper:", err)
+		os.Exit(2)
+	}
+
+	pipeline, err := gst.NewPipelineFromString(desc)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "pipeline:", err)
+		os.Exit(1)
+	}
+
+	// Rewrite PTS to a monotonic timeline on the encoder input: the portal
+	// delivers pts=0 on every buffer, which breaks HLS segmentation (hlssink
+	// cuts segments by timestamp) and gives the encoder no temporal reference.
+	if err := restampEncoderInput(pipeline, *fps); err != nil {
+		fmt.Fprintln(os.Stderr, "restamp:", err)
+		os.Exit(1)
+	}
+
+	if *mode == "h264" {
+		if err := wireH264Stdout(pipeline); err != nil {
+			fmt.Fprintln(os.Stderr, "appsink:", err)
+			os.Exit(1)
+		}
+	}
+
+	if err := pipeline.SetState(gst.StatePlaying); err != nil {
+		fmt.Fprintln(os.Stderr, "set playing:", err)
+		os.Exit(1)
+	}
+	runUntilDone(pipeline)
+}
+
+// buildPipeline assembles the GStreamer pipeline description.
+func buildPipeline(mode, out string, node, fps, bitrate, width, height int, test bool) (string, error) {
+	var src string
+	if test {
+		// Synthetic source — already system-memory, no DMA-BUF import needed.
+		src = fmt.Sprintf("videotestsrc is-live=true pattern=18 ! video/x-raw,width=%d,height=%d,framerate=%d/1,format=I420 ! videoconvert", width, height, fps)
+	} else {
+		// Portal PipeWire source: VA-import the DMA-BUF, scale, and force 4:2:0
+		// (I420). RGB screens would otherwise yield High 4:4:4 Predictive, which
+		// consumer TV/Cast decoders can't decode -> black.
+		src = fmt.Sprintf("pipewiresrc fd=%d path=%d do-timestamp=true ! vapostproc ! video/x-raw,width=%d,height=%d,format=I420 ! videoconvert", portalFD, node, width, height)
+	}
+
+	enc := fmt.Sprintf("x264enc name=enc tune=zerolatency speed-preset=superfast bitrate=%d key-int-max=%d byte-stream=true ! h264parse config-interval=-1", bitrate, fps)
+
+	switch mode {
+	case "h264":
+		return src + " ! " + enc + " ! video/x-h264,stream-format=byte-stream,alignment=au ! appsink name=sink sync=false max-buffers=8 drop=false", nil
+	case "hls":
+		if out == "" {
+			return "", fmt.Errorf("mode=hls requires -out <dir>")
+		}
+		hls := fmt.Sprintf("mpegtsmux ! hlssink location=%s/segment%%05d.ts playlist-location=%s/stream.m3u8 target-duration=1 max-files=10 playlist-length=5", out, out)
+		return src + " ! " + enc + " ! " + hls, nil
+	default:
+		return "", fmt.Errorf("unknown -mode %q (want h264|hls)", mode)
+	}
+}
+
+// restampEncoderInput adds a pad probe on the encoder's sink that rewrites each
+// buffer's PTS/duration to a monotonic fps timeline.
+func restampEncoderInput(pipeline *gst.Pipeline, fps int) error {
+	enc, err := pipeline.GetElementByName("enc")
+	if err != nil {
+		return err
+	}
+	sinkPad := enc.GetStaticPad("sink")
+	frameDur := uint64(time.Second) / uint64(fps)
+	var frame uint64
+	sinkPad.AddProbe(gst.PadProbeTypeBuffer, func(self *gst.Pad, info *gst.PadProbeInfo) gst.PadProbeReturn {
+		buf := info.GetBuffer()
+		if buf == nil {
+			return gst.PadProbeOK
+		}
+		buf.SetPresentationTimestamp(gst.ClockTime(frame * frameDur))
+		buf.SetDuration(gst.ClockTime(frameDur))
+		frame++
+		return gst.PadProbeOK
+	})
+	return nil
+}
+
+// wireH264Stdout streams appsink buffers (raw H.264 byte-stream) to stdout.
+func wireH264Stdout(pipeline *gst.Pipeline) error {
+	elem, err := pipeline.GetElementByName("sink")
+	if err != nil {
+		return err
+	}
+	sink := app.SinkFromElement(elem)
+	sink.SetCallbacks(&app.SinkCallbacks{
+		NewSampleFunc: func(s *app.Sink) gst.FlowReturn {
+			sample := s.PullSample()
+			if sample == nil {
+				return gst.FlowEOS
+			}
+			if _, err := os.Stdout.Write(sample.GetBuffer().Bytes()); err != nil {
+				return gst.FlowError
+			}
+			return gst.FlowOK
+		},
+	})
+	return nil
+}
+
+// runUntilDone blocks on the bus until EOS or error.
+func runUntilDone(pipeline *gst.Pipeline) {
+	bus := pipeline.GetBus()
+	for {
+		msg := bus.TimedPop(gst.ClockTime(uint64(gst.ClockTimeNone)))
+		if msg == nil {
+			continue
+		}
+		switch msg.Type() {
+		case gst.MessageEOS:
+			pipeline.SetState(gst.StateNull)
+			return
+		case gst.MessageError:
+			fmt.Fprintln(os.Stderr, "gst error:", msg.ParseError().Error())
+			pipeline.SetState(gst.StateNull)
+			os.Exit(1)
+		}
+	}
+}

core/cmd/dms-cast-helper/main_nocgo.go

@@ -0,0 +1,17 @@
+//go:build !casthelper
+
+// Stub built unless the `casthelper` tag is set, so a plain `go build ./...` /
+// `go test ./...` over the core stays green without GStreamer dev packages (and
+// without enabling CGO). The real GStreamer helper is built by `make
+// cast-helper`, which passes `-tags casthelper` with CGO_ENABLED=1.
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Fprintln(os.Stderr, "dms-cast-helper was built without GStreamer support; build it with `make cast-helper` (needs CGO + GStreamer dev packages)")
+	os.Exit(2)
+}

core/go.mod

@@ -10,12 +10,15 @@ require (
 	github.com/charmbracelet/lipgloss v1.1.0
 	github.com/charmbracelet/log v1.0.0
 	github.com/fsnotify/fsnotify v1.10.1
+	github.com/go-gst/go-gst v1.4.0
 	github.com/godbus/dbus/v5 v5.2.2
+	github.com/grandcat/zeroconf v1.0.0
 	github.com/holoplot/go-evdev v0.0.0-20260504100651-66d1748fe847
 	github.com/pilebones/go-udev v0.9.1
 	github.com/sblinch/kdl-go v0.0.0-20260121213736-8b7053306ca6
 	github.com/spf13/cobra v1.10.2
 	github.com/stretchr/testify v1.11.1
+	github.com/vishen/go-chromecast v0.3.4
 	github.com/yeqown/go-qrcode/v2 v2.2.5
 	github.com/yeqown/go-qrcode/writer/standard v1.3.0
 	github.com/yuin/goldmark v1.8.2
@@ -32,6 +35,8 @@ require (
 	github.com/Microsoft/go-winio v0.6.2 // indirect
 	github.com/ProtonMail/go-crypto v1.4.1 // indirect
 	github.com/akutz/memconn v0.1.0 // indirect
+	github.com/buger/jsonparser v1.1.1 // indirect
+	github.com/cenkalti/backoff v2.2.1+incompatible // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
 	github.com/cloudflare/circl v1.6.3 // indirect
@@ -44,29 +49,40 @@ require (
 	github.com/fxamacker/cbor/v2 v2.9.2 // indirect
 	github.com/go-git/gcfg/v2 v2.0.2 // indirect
 	github.com/go-git/go-billy/v6 v6.0.0-20260504142752-cb8e9d337266 // indirect
+	github.com/go-gst/go-glib v1.4.0 // indirect
 	github.com/go-json-experiment/json v0.0.0-20260430182902-b6187a392ed4 // indirect
 	github.com/go-logfmt/logfmt v0.6.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
+	github.com/h2non/filetype v1.1.3 // indirect
 	github.com/hdevalence/ed25519consensus v0.2.0 // indirect
 	github.com/jsimonetti/rtnetlink v1.4.2 // indirect
 	github.com/kevinburke/ssh_config v1.6.0 // indirect
 	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
+	github.com/mattn/go-pointer v0.0.1 // indirect
 	github.com/mdlayher/netlink v1.11.1 // indirect
 	github.com/mdlayher/socket v0.6.0 // indirect
+	github.com/miekg/dns v1.1.62 // indirect
+	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/go-ps v1.0.0 // indirect
 	github.com/pjbgf/sha1cd v0.6.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/sergi/go-diff v1.4.0 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
 	github.com/stretchr/objx v0.5.3 // indirect
 	github.com/tailscale/go-winio v0.0.0-20231025203758-c4f33415bf55 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/yeqown/reedsolomon v1.0.0 // indirect
 	go4.org/netipx v0.0.0-20231129151722-fdeea329fbba // indirect
 	golang.org/x/crypto v0.50.0 // indirect
+	golang.org/x/mod v0.35.0 // indirect
 	golang.org/x/net v0.53.0 // indirect
 	golang.org/x/sync v0.20.0 // indirect
+	golang.org/x/tools v0.44.0 // indirect
 	golang.zx2c4.com/wireguard/windows v1.0.1 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 )
 
 require (