Linux hardware acceleration build fixes

Remove the use_vaapi and use_nvidia Cargo features. Instead:

Always require libva on x86 Linux, checked with pkg-config.

If cuda.h exists, build with NVidia hardware acceleration support.
If you don't have an NVidia GPU, you probably don't have the CUDA
Toolkit installed, so the default build failed before. The only
reason to have the CUDA Toolkit installed if you don't have an
NVidia GPU is if you're building a binary that might be used on
machines with an NVidia GPU, which isn't necessary for development.

Also, allow specifying a non-default path for the CUDA Toolkit
with the CUDA_HOME environment variable.

Author: Be-ing

examples/wgpu_room/Cargo.toml

@@ -11,7 +11,7 @@ tracing = ["console-subscriber", "tokio/tracing"]
 [dependencies]
 tokio = { version = "1", features = ["full", "parking_lot"] }
 livekit = { workspace = true, features = ["rustls-tls-native-roots"]}
-webrtc-sys = { workspace = true, features = [ "use_vaapi", "use_nvidia" ] }
+webrtc-sys = { workspace = true }
 futures = "0.3"
 winit = { version = "0.30.11", features = [ "android-native-activity" ] }
 parking_lot = { version = "0.12.1", features = ["deadlock_detection"] }

livekit-ffi/Cargo.toml

@@ -20,7 +20,7 @@ tracing = ["tokio/tracing", "console-subscriber"]
 
 [dependencies]
 livekit = { workspace = true }
-webrtc-sys = { workspace = true , features = [ "use_vaapi", "use_nvidia" ]}
+webrtc-sys = { workspace = true }
 soxr-sys = { workspace = true }
 imgproc = { workspace = true }
 livekit-protocol = { workspace = true }

webrtc-sys/Cargo.toml

@@ -9,8 +9,6 @@ repository = "https://github.com/livekit/client-sdk-rust"
 
 [features]
 default = []
-use_vaapi = []
-use_nvidia = []
 
 [dependencies]
 cxx = "1.0"
@@ -21,6 +19,7 @@ webrtc-sys-build = { workspace = true }
 cxx-build = "1.0"
 glob = "0.3"
 cc = "1.0"
+pkg-config = "0.3.22"
 
 [dev-dependencies]
 env_logger = "0.10"

webrtc-sys/build.rs

@@ -153,22 +153,38 @@ fn main() {
             println!("cargo:rustc-link-lib=dylib=pthread");
             println!("cargo:rustc-link-lib=dylib=m");
 
-            match target_arch.as_str() {
-                "x86_64" => {
-                    #[cfg(feature = "use_vaapi")]
-                    builder
-                        .file("src/vaapi/vaapi_display_drm.cpp")
-                        .file("src/vaapi/vaapi_h264_encoder_wrapper.cpp")
-                        .file("src/vaapi/vaapi_encoder_factory.cpp")
-                        .file("src/vaapi/h264_encoder_impl.cpp")
-                        .file("src/vaapi/implib/libva-drm.so.init.c")
-                        .file("src/vaapi/implib/libva-drm.so.tramp.S")
-                        .file("src/vaapi/implib/libva.so.init.c")
-                        .file("src/vaapi/implib/libva.so.tramp.S")
-                        .flag("-DUSE_VAAPI_VIDEO_CODEC=1");
-
-                    #[cfg(feature = "use_nvidia")]
+            let x86 = target_arch == "x86_64" || target_arch == "i686";
+            let arm = target_arch == "aarch64" || target_arch.contains("arm");
+
+            if x86 {
+                // Do not use pkg_config::probe_library because libva is dlopened
+                // and pkg_config::probe_library would link it.
+                let libva_include = pkg_config::get_variable("libva", "includedir")
+                    .expect("libva development headers not found");
+                builder
+                    .include(libva_include)
+                    .file("src/vaapi/vaapi_display_drm.cpp")
+                    .file("src/vaapi/vaapi_h264_encoder_wrapper.cpp")
+                    .file("src/vaapi/vaapi_encoder_factory.cpp")
+                    .file("src/vaapi/h264_encoder_impl.cpp")
+                    .file("src/vaapi/implib/libva-drm.so.init.c")
+                    .file("src/vaapi/implib/libva-drm.so.tramp.S")
+                    .file("src/vaapi/implib/libva.so.init.c")
+                    .file("src/vaapi/implib/libva.so.tramp.S")
+                    .flag("-DUSE_VAAPI_VIDEO_CODEC=1");
+            }
+
+            if x86 || arm {
+                let cuda_home = PathBuf::from(match env::var("CUDA_HOME") {
+                    Ok(p) => p,
+                    Err(_) => "/usr/local/cuda".to_owned(),
+                });
+                let cuda_include_dir = cuda_home.join("include");
+
+                // libcuda and libnvcuvid are dlopened, so do not link them.
+                if cuda_include_dir.join("cuda.h").exists() {
                     builder
+                        .include(cuda_include_dir)
                         .flag("-I/usr/local/cuda/include")
                         .flag("-Isrc/nvidia/NvCodec/include")
                         .flag("-Isrc/nvidia/NvCodec/NvCodec")
@@ -186,8 +202,9 @@ fn main() {
                         .file("src/nvidia/implib/libnvcuvid.so.tramp.S")
                         .flag("-Wno-deprecated-declarations")
                         .flag("-DUSE_NVIDIA_VIDEO_CODEC=1");
+                } else {
+                    println!("cargo:warning=cuda.h not found; building without hardware accelerated video codec support for NVidia GPUs");
                 }
-                _ => {}
             }
 
             builder.flag("-Wno-changes-meaning").flag("-std=c++20");