WASAPI: Use ActivateAudioInterfaceAsync with virtual device IDs for default devices

.github/workflows/platforms.yml

@@ -351,44 +351,6 @@ jobs:
       - name: Build beep example
         run: cargo build --example beep --target ${{ env.TARGET }}
 
-  # Windows crate version compatibility
-  windows-versions:
-    runs-on: windows-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        version: ["0.59.0", "0.60.0", "0.61.3"]
-
-    name: windows-crate-v${{ matrix.version }}
-    steps:
-      - uses: actions/checkout@v5
-
-      - name: Install dependencies
-        run: choco install llvm
-
-      - name: Install Rust MSRV (${{ env.MSRV_WINDOWS }})
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: ${{ env.MSRV_WINDOWS }}
-
-      - name: Rust Cache
-        uses: Swatinem/rust-cache@v2
-        with:
-          key: windows-v${{ matrix.version }}
-
-      - name: Lock windows crate to specific version
-        shell: bash
-        run: |
-          cargo generate-lockfile
-          cargo update -p windows --precise ${{ matrix.version }}
-          echo "Locked windows crate version:"
-          cargo tree | grep "windows v" || echo "Windows crate not found in dependency tree"
-          echo "Cargo.lock entry:"
-          grep -A 5 "name = \"windows\"" Cargo.lock | head -10
-
-      - name: Check WASAPI with windows v${{ matrix.version }}
-        run: cargo check --verbose
-
   # cpal publishing (only on cpal release events)
   publish-cpal:
     if: github.event_name == 'release' && startsWith(github.ref, 'refs/tags/v')
@@ -403,7 +365,6 @@ jobs:
       - wasm-bindgen
       - wasm-audioworklet
       - wasm-wasip1
-      - windows-versions
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5

Cargo.toml

@@ -10,6 +10,8 @@ edition = "2021"
 rust-version = "1.77"
 
 [features]
+default = []
+
 # ASIO backend for Windows
 # Provides low-latency audio I/O by bypassing the Windows audio stack
 # Requires: ASIO drivers and LLVM/Clang for build-time bindings
@@ -19,6 +21,19 @@ asio = [
     "dep:num-traits",
 ]
 
+# Legacy Windows audio device activation mode. When enabled:
+# - Uses IMMDevice::Activate instead of ActivateAudioInterfaceAsync
+# - Audio does NOT automatically reroute when the default device changes
+# - Streams will break when the default device changes (e.g., plugging in headphones)
+#
+# By default (without this feature), CPAL uses virtual default devices that:
+# - Automatically reroute audio when the default device changes
+# - Allow streams to survive device changes
+# - Require Windows 8 or later
+#
+# Enable this feature only if supporting Windows 7 or earlier.
+windows-legacy = []
+
 # JACK Audio Connection Kit backend
 # Provides low-latency connections between applications and audio hardware
 # Requires: JACK server and client libraries installed on the system
@@ -62,11 +77,8 @@ hound = "3.5"
 ringbuf = "0.4"
 clap = { version = ">=4.0, <=4.5", features = ["derive"] }
 
-# Support a range of versions in order to avoid duplication of this crate. Make sure to test all
-# versions when bumping to a new release, and only increase the minimum when absolutely necessary.
-# When updating this, also update the "windows-version" matrix in the CI workflow.
 [target.'cfg(target_os = "windows")'.dependencies]
-windows = { version = ">=0.59, <=0.62", features = [
+windows = { version = "0.62.2", features = [
     "Win32_Media_Audio",
     "Win32_Foundation",
     "Win32_Devices_Properties",
@@ -79,6 +91,8 @@ windows = { version = ">=0.59, <=0.62", features = [
     "Win32_Media_Multimedia",
     "Win32_UI_Shell_PropertiesSystem",
 ] }
+# Explicitly depend on windows-core for use with the `windows::core::implement` macro.
+windows-core = "0.62.2"
 audio_thread_priority = { version = "0.34", optional = true }
 asio-sys = { version = "0.2", path = "asio-sys", optional = true }
 num-traits = { version = "0.2", optional = true }

src/host/wasapi/com.rs

@@ -4,7 +4,9 @@ use super::IoError;
 use std::marker::PhantomData;
 
 use windows::Win32::Foundation::RPC_E_CHANGED_MODE;
-use windows::Win32::System::Com::{CoInitializeEx, CoUninitialize, COINIT_APARTMENTTHREADED};
+use windows::Win32::System::Com::{
+    CoInitializeEx, CoTaskMemFree, CoUninitialize, COINIT_APARTMENTTHREADED,
+};
 
 thread_local!(static COM_INITIALIZED: ComInitialized = {
     unsafe {
@@ -49,6 +51,14 @@ impl Drop for ComInitialized {
     }
 }
 
+/// RAII for COM-originating strings that need to be freed with `CoTaskMemFree`.
+pub struct ComString(pub windows::core::PWSTR);
+impl Drop for ComString {
+    fn drop(&mut self) {
+        unsafe { CoTaskMemFree(Some(self.0.as_ptr() as *mut _)) }
+    }
+}
+
 /// Ensures that COM is initialized in this thread.
 #[inline]
 pub fn com_initialized() {