feat(pipeline): symmetric RGB-direct logging + rgb_direct_encode override

Author: porkloin

src/config.rs

@@ -251,6 +251,27 @@ pub struct VideoStreamConfig {
 	/// the messages can be very noisy.
 	#[serde(default = "default_false")]
 	pub log_frame_spikes: bool,
+
+	/// Controls use of `VK_VALVE_video_encode_rgb_conversion`, which lets the
+	/// video encoder do RGB→YUV conversion inline (skipping the compute-shader
+	/// convert path). Currently only RADV (AMD on Linux) advertises the
+	/// extension; other drivers fall through to the compute-shader path.
+	///
+	/// - `auto` (default): use it when the device advertises support.
+	/// - `off`: always use the compute-shader path, even when supported.
+	///   Useful as an escape hatch if a driver regresses or for A/B testing.
+	/// - `force`: require it; encoder creation fails loudly if not supported.
+	#[serde(default)]
+	pub rgb_direct_encode: RgbDirectMode,
+}
+
+#[derive(Clone, Copy, Debug, Default, Serialize, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "lowercase")]
+pub enum RgbDirectMode {
+	#[default]
+	Auto,
+	Off,
+	Force,
 }
 
 impl Default for VideoStreamConfig {
@@ -260,6 +281,7 @@ impl Default for VideoStreamConfig {
 			fec_percentage: 20,
 			encrypt: false,
 			log_frame_spikes: false,
+			rgb_direct_encode: RgbDirectMode::default(),
 		}
 	}
 }

src/session/stream/video/mod.rs

@@ -253,6 +253,7 @@ impl VideoStreamInner {
 			stop_session_manager.clone(),
 			hdr_metadata_tx,
 			self.config.stream.video.log_frame_spikes,
+			self.config.stream.video.rgb_direct_encode,
 		)?;
 
 		self.pipeline = Some(pipeline);

src/session/stream/video/pipeline/mod.rs

@@ -14,6 +14,7 @@ use ash::vk;
 use async_shutdown::ShutdownManager;
 use tokio::sync::{broadcast, mpsc, watch};
 
+use crate::config::RgbDirectMode;
 use crate::session::compositor::frame::{ExportedFrame, FrameColorSpace, HdrModeState};
 use crate::session::manager::SessionShutdownReason;
 
@@ -142,6 +143,7 @@ impl VideoPipeline {
 		stop_session_manager: ShutdownManager<SessionShutdownReason>,
 		hdr_metadata_tx: watch::Sender<HdrModeState>,
 		log_frame_spikes: bool,
+		rgb_direct_mode: RgbDirectMode,
 	) -> Result<Self, ()> {
 		tracing::debug!("Initializing video pipeline.");
 
@@ -159,6 +161,7 @@ impl VideoPipeline {
 			max_reference_frames,
 			encryption_key,
 			log_frame_spikes,
+			rgb_direct_mode,
 		};
 
 		std::thread::Builder::new()
@@ -192,6 +195,8 @@ struct VideoPipelineInner {
 	max_reference_frames: u32,
 	encryption_key: Option<Vec<u8>>,
 	log_frame_spikes: bool,
+	/// Controls VK_VALVE_video_encode_rgb_conversion usage at encoder creation.
+	rgb_direct_mode: RgbDirectMode,
 }
 
 impl VideoPipelineInner {
@@ -251,10 +256,32 @@ impl VideoPipelineInner {
 
 		// RGB-direct encode skips the compute-shader RGB→YUV pass and lets
 		// the video encoder hardware do the conversion inline. Enabled
-		// whenever the device advertises VK_VALVE_video_encode_rgb_conversion.
-		let use_rgb_input = context.supports_rgb_direct_encode();
-		if use_rgb_input {
-			tracing::info!("RGB-direct encode path active (VK_VALVE_video_encode_rgb_conversion)");
+		// whenever the device advertises VK_VALVE_video_encode_rgb_conversion,
+		// unless overridden via [stream.video] rgb_direct_encode in config.
+		let device_supports_rgb_direct = context.supports_rgb_direct_encode();
+		let use_rgb_input = match self.rgb_direct_mode {
+			RgbDirectMode::Auto => device_supports_rgb_direct,
+			RgbDirectMode::Off => false,
+			RgbDirectMode::Force => {
+				if !device_supports_rgb_direct {
+					return Err(
+						"rgb_direct_encode = \"force\" but VK_VALVE_video_encode_rgb_conversion \
+						is not advertised by this device"
+							.to_string(),
+					);
+				}
+				true
+			},
+		};
+		match (self.rgb_direct_mode, device_supports_rgb_direct, use_rgb_input) {
+			(_, _, true) => tracing::info!("RGB-direct encode path active (VK_VALVE_video_encode_rgb_conversion)"),
+			(RgbDirectMode::Off, true, _) => tracing::info!(
+				"Compute-shader RGB→YUV path active (rgb_direct_encode = \"off\" overrides device support)"
+			),
+			(_, false, _) => tracing::info!(
+				"Compute-shader RGB→YUV path active (VK_VALVE_video_encode_rgb_conversion not supported by this device)"
+			),
+			_ => {},
 		}
 
 		// Convert pixel format.