Capture: argus backend for device source

.changeset/capture-source-device-argus.md

@@ -0,0 +1,6 @@
+---
+livekit-capture: minor
+livekit-ffi: minor
+---
+
+Add NVIDIA Jetson CSI camera capture on Linux.

libargus-sys/build.rs

@@ -31,9 +31,7 @@ fn find_tegra_lib_dir() -> Option<PathBuf> {
         ],
     };
 
-    candidates
-        .into_iter()
-        .find(|dir| REQUIRED_LIBS.iter().all(|lib| dir.join(lib).exists()))
+    candidates.into_iter().find(|dir| REQUIRED_LIBS.iter().all(|lib| dir.join(lib).exists()))
 }
 
 fn main() {

libargus-sys/src/lib.rs

@@ -91,9 +91,7 @@ pub fn lk_argus_status_string(status: i32) -> &'static str {
     match status {
         LK_ARGUS_OK => "ok",
         LK_ARGUS_ERR_INVALID_ARG => "invalid argument",
-        LK_ARGUS_ERR_NO_PROVIDER => {
-            "failed to create camera provider (is nvargus-daemon running?)"
-        }
+        LK_ARGUS_ERR_NO_PROVIDER => "failed to create camera provider (is nvargus-daemon running?)",
         LK_ARGUS_ERR_NO_DEVICE => "camera device index out of range",
         LK_ARGUS_ERR_ARGUS => "Argus operation failed",
         LK_ARGUS_ERR_TIMEOUT => "frame acquire timed out",

livekit-capture/Cargo.toml

@@ -90,6 +90,12 @@ source-device = [
     "dep:libc",
     "dep:v4l",
 ]
+# Adds NVIDIA Jetson CSI capture through libargus as an additional Linux
+# device-source backend. The libargus-sys build probes for the Jetson
+# Multimedia API and falls back to inert stubs when it is absent, so this
+# feature compiles on any target; it only has an effect on aarch64 Linux
+# (inert elsewhere).
+source-device-argus = ["source-device", "dep:libargus-sys"]
 source-pattern = ["dep:pollster", "dep:wgpu", "dep:yuv-sys"]
 
 # Encoded sources
@@ -122,5 +128,6 @@ objc2-foundation = { version = "0.3.2", default-features = false, features = ["s
 
 [target.'cfg(target_os = "linux")'.dependencies]
 image = { workspace = true, optional = true }
+libargus-sys = { workspace = true, optional = true }
 libc = { version = "0.2", optional = true }
 v4l = { version = "0.14", default-features = false, features = ["v4l2"], optional = true }

livekit-capture/README.md

@@ -62,6 +62,10 @@ named `source-<module>`. Each module documents its source.
 | `source-pattern`   | `PatternVideoSource`   | pixel   |
 | `source-clock`     | `ClockVideoSource`     | pixel   |
 
+`source-device-argus` extends `DeviceVideoSource` with an NVIDIA Jetson CSI
+backend (libargus, zero-copy NV12 DMA buffers) on Linux; it is inert on
+other platforms and on machines without the Jetson stack.
+
 `source-rtsp-tls` extends `RtspVideoSource` with `rtsps://` support (RTSP
 over TLS 1.2+). Certificates are verified against the system roots by
 default; cameras with self-signed certificates can opt out per source.