output/pipewire: attempt to change the graph sample rate

Requires PipeWire 0.3.32.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1283

NEWS

@@ -1,5 +1,6 @@
 ver 0.23.1 (not yet released)
 * output
+  - pipewire: attempt to change the graph sample rate
   - snapcast: fix time stamp bug which caused "Failed to get chunk"
 * fix libfmt linker problems
 * fix broken password authentication

src/output/plugins/PipeWireOutputPlugin.cxx

@@ -383,6 +383,13 @@ PipeWireOutput::Open(AudioFormat &audio_format)
 	if (target != nullptr && target_id == PW_ID_ANY)
 		pw_properties_setf(props, PW_KEY_NODE_TARGET, "%s", target);
 
+#ifdef PW_KEY_NODE_RATE
+	/* ask PipeWire to change the graph sample rate to ours
+	   (requires PipeWire 0.3.32) */
+	pw_properties_setf(props, PW_KEY_NODE_RATE, "1/%u",
+			   audio_format.sample_rate);
+#endif
+
 	const PipeWire::ThreadLoopLock lock(thread_loop);
 
 	stream = pw_stream_new_simple(pw_thread_loop_get_loop(thread_loop),