fix(moq-video): nightly's Windows platform job passes

quest/m0/nightly/README.md

@@ -51,4 +51,3 @@ near the paired threshold (re-check if one repeats), a one-off
 ## Required
 
 - [Nightly's macOS platform job passes](/quest/m0/nightly/macos.md) - `moq-audio`'s tests compile on macOS again and the websocket version test's timeout is fixed if it recurs
-- [Nightly's Windows platform job passes](/quest/m0/nightly/windows.md) - `moq-vaapi` is gated to Linux and Windows-only unused items are fixed, so `platform.yml`'s Windows job builds and tests cleanly

rs/moq-video/src/encode/backend/mod.rs

@@ -80,7 +80,15 @@ pub(crate) trait Backend {
 	fn flush(&mut self) -> Result<(), Error>;
 
 	/// Submit one frame and collect everything it readied.
-	#[cfg(test)]
+	#[cfg(all(
+		test,
+		any(
+			feature = "openh264",
+			apple,
+			all(target_os = "android", feature = "mediacodec"),
+			all(target_os = "linux", feature = "vaapi"),
+		)
+	))]
 	fn encode_all(&mut self, frame: &Frame, cut: bool) -> Result<Vec<Encoded>, Error> {
 		self.encode(frame, cut)?;
 		self.receive_all()