diff --git a/agent/src/config.rs b/agent/src/config.rs
index a3884d8..eab4641 100644
--- a/agent/src/config.rs
+++ b/agent/src/config.rs
@@ -22,10 +22,14 @@ pub struct AgentConfig {
     pub session_id: Option<String>,
 
     /// Target capture frame rate (frames per second).
-    #[arg(long, default_value_t = 30, env = "BUTTERFLY_FPS")]
+    #[arg(long, default_value_t = 60, env = "BUTTERFLY_FPS")]
     pub fps: u32,
 
-    /// JPEG encoding quality (1–100). Lower = smaller frames, less quality.
+    /// Video encoder backend: "h264" (low-latency, GPU-optional) or "jpeg" (fallback).
+    #[arg(long, default_value = "h264", env = "BUTTERFLY_ENCODER")]
+    pub encoder: String,
+
+    /// Encoding quality (1–100). For H.264 this maps to bitrate; for JPEG it's direct quality.
     #[arg(long, default_value_t = 60, env = "BUTTERFLY_QUALITY")]
     pub quality: u8,