diff --git a/lib-gst-meet-c/include/gstmeet.h b/lib-gst-meet-c/include/gstmeet.h
index cc305f1..8a14473 100644
--- a/lib-gst-meet-c/include/gstmeet.h
+++ b/lib-gst-meet-c/include/gstmeet.h
@@ -72,4 +72,8 @@ void gstmeet_conference_on_participant(struct Context *context,
                                        GstBin *(*f)(struct Participant, void *),
                                        void *callback_context);
 
+bool gstmeet_conference_set_pipeline_state(struct Context *context,
+                                           JitsiConference *conference,
+                                           GstState state);
+
 #endif /* gstmeet_h */
diff --git a/lib-gst-meet-c/src/lib.rs b/lib-gst-meet-c/src/lib.rs
index 571fc95..a6feb1b 100644
--- a/lib-gst-meet-c/src/lib.rs
+++ b/lib-gst-meet-c/src/lib.rs
@@ -6,7 +6,7 @@ use std::{
 };
 
 use anyhow::Result;
-use glib::{ffi::GMainContext, translate::{from_glib_full, ToGlibPtr}};
+use glib::{ffi::GMainContext, translate::{from_glib, from_glib_full, ToGlibPtr}};
 pub use lib_gst_meet::{init_tracing, JitsiConference, JitsiConnection, MediaType};
 use lib_gst_meet::JitsiConferenceConfig;
 use tokio::runtime::Runtime;
@@ -214,4 +214,17 @@ pub unsafe extern "C" fn gstmeet_conference_on_participant(
         }
       })
     }));
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn gstmeet_conference_set_pipeline_state(
+  context: *mut Context,
+  conference: *mut JitsiConference,
+  state: gstreamer::ffi::GstState,
+) -> bool {
+  (*context)
+    .runtime
+    .block_on((*conference).set_pipeline_state(from_glib(state)))
+    .map_err(|e| eprintln!("lib-gst-meet: {:?}", e))
+    .is_ok()
 }
\ No newline at end of file
diff --git a/lib-gst-meet/src/conference.rs b/lib-gst-meet/src/conference.rs
index 7bf4419..7f6f5e0 100644
--- a/lib-gst-meet/src/conference.rs
+++ b/lib-gst-meet/src/conference.rs
@@ -533,7 +533,16 @@ impl StanzaFilter for JitsiConference {
                       nick: item.nick,
                       bin: None,
                     };
-                    if locked_inner
+                    if presence.type_ == presence::Type::Unavailable && locked_inner.participants.remove(&from.resource.clone()).is_some() {
+                      debug!("participant left: {:?}", jid);
+                      if let Some(f) = &locked_inner.on_participant_left {
+                        debug!("calling on_participant_left with old participant");
+                        if let Err(e) = f(participant).await {
+                          warn!("on_participant_left failed: {:?}", e);
+                        }
+                      }
+                    }
+                    else if locked_inner
                       .participants
                       .insert(from.resource.clone(), participant.clone())
                       .is_none()
@@ -558,16 +567,6 @@ impl StanzaFilter for JitsiConference {
                         }
                       }
                     }
-                    else if presence.type_ == presence::Type::Unavailable {
-                      locked_inner.participants.remove(&from.resource.clone());
-                      debug!("participant left: {:?}", jid);
-                      if let Some(f) = &locked_inner.on_participant_left {
-                        debug!("calling on_participant_left with old participant");
-                        if let Err(e) = f(participant).await {
-                          warn!("on_participant_left failed: {:?}", e);
-                        }
-                      }
-                    }
                   }
                 }
               }
diff --git a/shell.nix b/shell.nix
index d08a169..b6efbeb 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,4 +1,9 @@
 with import <nixpkgs> {};
+let
+  gst-plugins-base = gst_all_1.gst-plugins-base.override {
+    enableCocoa = stdenv.isDarwin;
+  };
+in
 mkShell {
   name = "gst-meet";
   buildInputs = [
@@ -6,7 +11,7 @@ mkShell {
     glib
     glib-networking
     gst_all_1.gstreamer
-    gst_all_1.gst-plugins-base
+    gst-plugins-base
     gst_all_1.gst-plugins-good
     gst_all_1.gst-plugins-bad
     libnice