(WIP) Integrate livekit capture

.github/workflows/tests.yml

@@ -132,6 +132,11 @@ env:
   VCPKG_DEFAULT_TRIPLET: x64-windows-static-md
   VCPKG_DEFAULT_HOST_TRIPLET: x64-windows-static-md
   VCPKG_TARGET_TRIPLET: x64-windows-static-md
+  # Windows uses an explicit, checksum-pinned GStreamer SDK. Linux and macOS
+  # intentionally use their supported platform-package versions; `1.0` in
+  # Ubuntu package names denotes the GStreamer ABI, not the installed release.
+  GSTREAMER_WINDOWS_VERSION: "1.28.5"
+  GSTREAMER_WINDOWS_SHA256: "51ee5eaec33008e8409d8cf6f6884457f22aa3bd515f8856f993a3eaab903530"
 
 jobs:
   test:
@@ -209,6 +214,34 @@ jobs:
         with:
           vcpkgGitCommitId: ${{ env.VCPKG_GIT_COMMIT }}
 
+      - name: Install GStreamer (Windows)
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: |
+          $installer = Join-Path $env:RUNNER_TEMP "gstreamer-installer.exe"
+          $installDir = Join-Path $env:RUNNER_TEMP "gstreamer"
+          $uri = "https://gstreamer.freedesktop.org/data/pkg/windows/$env:GSTREAMER_WINDOWS_VERSION/msvc/gstreamer-1.0-msvc-x86_64-$env:GSTREAMER_WINDOWS_VERSION.exe"
+
+          Invoke-WebRequest -Uri $uri -OutFile $installer
+          $actualHash = (Get-FileHash -Algorithm SHA256 $installer).Hash.ToLowerInvariant()
+          if ($actualHash -ne $env:GSTREAMER_WINDOWS_SHA256) {
+            throw "GStreamer installer SHA-256 mismatch: expected $env:GSTREAMER_WINDOWS_SHA256, got $actualHash"
+          }
+
+          $process = Start-Process -FilePath $installer -ArgumentList @(
+            "/TYPE=devel",
+            "/DIR=$installDir",
+            "/CURRENTUSER",
+            "/VERYSILENT",
+            "/NORESTART"
+          ) -Wait -PassThru
+          if ($process.ExitCode -ne 0) {
+            throw "GStreamer installer failed with exit code $($process.ExitCode)"
+          }
+
+          "$installDir\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+          "PKG_CONFIG_PATH=$installDir\lib\pkgconfig" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
+
       # ---------- OS-specific deps ----------
       - name: Install deps (Ubuntu)
         if: runner.os == 'Linux'
@@ -227,14 +260,19 @@ jobs:
             libabsl-dev \
             libcurl4-openssl-dev \
             libwayland-dev libdecor-0-dev \
+            libunwind-dev libjpeg-dev \
+            libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
+            gstreamer1.0-plugins-base gstreamer1.0-plugins-good \
+            gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly \
+            gstreamer1.0-libav \
             gdb jq
 
       - name: Install deps (macOS)
         if: runner.os == 'macOS'
         run: |
           set -eux
           brew update
-          brew install cmake ninja protobuf abseil
+          brew install cmake ninja protobuf abseil gstreamer
 
       # ---------- Rust toolchain ----------
       - name: Install Rust (stable)
@@ -508,7 +546,12 @@ jobs:
             libprotobuf-dev protobuf-compiler \
             libabsl-dev \
             libcurl4-openssl-dev \
-            libwayland-dev libdecor-0-dev
+            libwayland-dev libdecor-0-dev \
+            libunwind-dev libjpeg-dev \
+            libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev \
+            gstreamer1.0-plugins-base gstreamer1.0-plugins-good \
+            gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly \
+            gstreamer1.0-libav
           pip install --break-system-packages gcovr
 
       # ---------- Rust toolchain ----------

CMakeLists.txt

@@ -18,6 +18,7 @@ include(warnings)
 
 option(LIVEKIT_BUILD_EXAMPLES "Build LiveKit examples" OFF)
 option(LIVEKIT_BUILD_TESTS "Build LiveKit tests" OFF)
+option(LIVEKIT_ENABLE_CAPTURE "Build the Rust FFI with the capture feature (livekit-capture sources; links system GStreamer)" OFF)
 
 # vcpkg is only used on Windows; Linux/macOS use system package managers
 if(WIN32)
@@ -85,6 +86,7 @@ set(FFI_PROTO_FILES
     ${FFI_PROTO_DIR}/data_track.proto
     ${FFI_PROTO_DIR}/rpc.proto
     ${FFI_PROTO_DIR}/track_publication.proto
+    ${FFI_PROTO_DIR}/capture.proto
 )
 set(PROTO_BINARY_DIR ${LIVEKIT_BINARY_DIR}/generated)
 file(MAKE_DIRECTORY ${PROTO_BINARY_DIR})
@@ -166,6 +168,14 @@ set(GENERATED_BUILD_H "${LIVEKIT_ROOT_DIR}/include/livekit/build.h")
 set(GENERATED_BUILD_INFO_JSON "${LIVEKIT_BINARY_DIR}/build-info.json")
 set(RUST_ROOT ${LIVEKIT_ROOT_DIR}/client-sdk-rust)
 
+# Cargo features for the Rust FFI build.
+set(LIVEKIT_CARGO_FEATURES "")
+set(LIVEKIT_CAPTURE_ENABLED 0)
+if(LIVEKIT_ENABLE_CAPTURE)
+  set(LIVEKIT_CARGO_FEATURES "capture")
+  set(LIVEKIT_CAPTURE_ENABLED 1)
+endif()
+
 set(GIT_COMMIT "unknown")
 set(RUST_GIT_COMMIT "unknown")
 find_package(Git QUIET)
@@ -261,6 +271,11 @@ if(NOT CFG STREQUAL \"Debug\")
   list(APPEND ARGS --release)
 endif()
 
+if(DEFINED CARGO_FEATURES AND NOT CARGO_FEATURES STREQUAL \"\")
+  list(APPEND ARGS --features \"\${CARGO_FEATURES}\")
+  message(STATUS \"[run_cargo.cmake] Cargo features: \${CARGO_FEATURES}\")
+endif()
+
 if(DEFINED RUST_TARGET AND NOT RUST_TARGET STREQUAL \"\")
   list(APPEND ARGS --target \"\${RUST_TARGET}\")
   message(STATUS \"[run_cargo.cmake] Cross-compiling for target: \${RUST_TARGET}\")
@@ -357,6 +372,7 @@ add_custom_command(
           -DPROTOC_PATH=${Protobuf_PROTOC_EXECUTABLE}
           -DRUST_TARGET=${RUST_TARGET_TRIPLE}
           -DGCC_LIB_DIR=${GCC_LIB_DIR}
+          -DCARGO_FEATURES=${LIVEKIT_CARGO_FEATURES}
           -P "${RUN_CARGO_SCRIPT}"
   WORKING_DIRECTORY "${RUST_ROOT}"
   DEPENDS ${RUST_SOURCES}
@@ -373,6 +389,8 @@ add_custom_target(build_rust_ffi
 add_library(livekit SHARED
   src/audio_frame.cpp
   src/audio_processing_module.cpp
+  src/capture_source.cpp
+  src/capture_source_internal.h
   src/audio_source.cpp
   src/audio_stream.cpp
   src/data_track_frame.cpp

CMakePresets.json

@@ -214,7 +214,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -226,7 +227,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -238,7 +240,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -250,7 +253,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -262,7 +266,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -274,7 +279,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -286,7 +292,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -298,7 +305,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -310,7 +318,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -322,7 +331,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "ON",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -334,7 +344,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     },
     {
@@ -346,7 +357,8 @@
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Debug",
         "LIVEKIT_BUILD_EXAMPLES": "OFF",
-        "LIVEKIT_BUILD_TESTS": "ON"
+        "LIVEKIT_BUILD_TESTS": "ON",
+        "LIVEKIT_ENABLE_CAPTURE": "ON"
       }
     }
   ],

build.h.in

@@ -6,16 +6,23 @@
 
 // Version injected by CMake (CI should set it). Defaults to 0.0.0 for dev builds.
 #define LIVEKIT_BUILD_VERSION "@LIVEKIT_VERSION@"
-#define LIVEKIT_BUILD_FLAVOR "cpp"   
+#define LIVEKIT_BUILD_FLAVOR "cpp"
+
+namespace livekit {
+
+/// @brief Whether the Rust FFI was built with capture-source support.
+inline constexpr bool kCaptureEnabled = "@LIVEKIT_CAPTURE_ENABLED@"[0] == '1';
+
+} // namespace livekit
 
 #ifdef DEBUG
-#define LIVEKIT_BUILD_SUFFIX  "-debug"
+#define LIVEKIT_BUILD_SUFFIX "-debug"
 #else
-#define LIVEKIT_BUILD_SUFFIX  "-release"
+#define LIVEKIT_BUILD_SUFFIX "-release"
 #endif
 
 // Follow params are auto generated by CMakeLists.txt
-#define LIVEKIT_BUILD_DATE "@BUILD_DATE@" 
+#define LIVEKIT_BUILD_DATE "@BUILD_DATE@"
 #define LIVEKIT_BUILD_COMMIT "@GIT_COMMIT@"
 
-#define LIVEKIT_BUILD_VERSION_FULL LIVEKIT_BUILD_VERSION LIVEKIT_BUILD_SUFFIX
+#define LIVEKIT_BUILD_VERSION_FULL LIVEKIT_BUILD_VERSION LIVEKIT_BUILD_SUFFIX