diff --git a/Cargo.lock b/Cargo.lock
index 485f2a3..5df7241 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -473,7 +473,7 @@ dependencies = [
 
 [[package]]
 name = "gst-meet"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "anyhow",
  "cocoa",
@@ -663,7 +663,7 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "lib-gst-meet"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -751,15 +751,6 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
 
-[[package]]
-name = "matchers"
-version = "0.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f099785f7595cc4b4553a174ce30dd7589ef93391ff414dbb67f62392b9e0ce1"
-dependencies = [
- "regex-automata",
-]
-
 [[package]]
 name = "matches"
 version = "0.1.9"
@@ -1225,15 +1216,6 @@ dependencies = [
  "regex-syntax",
 ]
 
-[[package]]
-name = "regex-automata"
-version = "0.1.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
-dependencies = [
- "regex-syntax",
-]
-
 [[package]]
 name = "regex-syntax"
 version = "0.6.25"
@@ -1651,14 +1633,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ab69019741fca4d98be3c62d2b75254528b5432233fd8a4d2739fec20278de48"
 dependencies = [
  "chrono",
- "lazy_static",
- "matchers",
  "parking_lot",
- "regex",
  "sharded-slab",
  "smallvec",
  "thread_local",
- "tracing",
  "tracing-core",
  "tracing-log",
 ]
diff --git a/README.md b/README.md
index d02d8aa..6df9006 100644
--- a/README.md
+++ b/README.md
@@ -57,14 +57,14 @@ gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
                           demuxer.audio_0 ! queue ! vorbisdec ! audioconvert ! audioresample ! opusenc name=audio"
 ```
 
-Stream the default macOS video & audio inputs to the conference, encoding as VP8 and Opus, display incoming video streams and play back incoming audio (a very basic, but completely native, Jitsi Meet conference!):
+Stream the default video & audio inputs to the conference, encoding as VP8 and Opus, composite incoming video streams and play back incoming audio (a very basic, but completely native, Jitsi Meet conference!):
 
 ```
 gst-meet --web-socket-url=wss://your.jitsi.domain/xmpp-websocket \
          --xmpp-domain=your.jitsi.domain \
          --room-name=roomname \
-         --send-pipeline="avfvideosrc ! queue ! videoconvert ! vp8enc buffer-size=1000 deadline=1 name=video
-                          osxaudiosrc ! queue ! audioconvert ! audioresample ! opusenc name=audio" \
+         --send-pipeline="autovideosrc ! queue ! videoconvert ! vp8enc buffer-size=1000 deadline=1 name=video
+                          autoaudiosrc ! queue ! audioconvert ! audioresample ! opusenc name=audio" \
          --recv-pipeline-participant-template="opusdec name=audio ! autoaudiosink
                                                vp8dec name=video ! videoconvert ! autovideosink"
 ```
diff --git a/gst-meet/Cargo.toml b/gst-meet/Cargo.toml
index a6a593a..db9c859 100644
--- a/gst-meet/Cargo.toml
+++ b/gst-meet/Cargo.toml
@@ -18,7 +18,6 @@ tokio-stream = { version = "0.1", default-features = false }
 tracing = { version = "0.1", default-features = false, features = ["attributes", "std"] }
 tracing-subscriber = { version = "0.2", default-features = false, features = [
   "chrono",
-  "env-filter",
   "fmt",
   "smallvec",
   "parking_lot",
diff --git a/gst-meet/src/main.rs b/gst-meet/src/main.rs
index f0fcf74..d397fad 100644
--- a/gst-meet/src/main.rs
+++ b/gst-meet/src/main.rs
@@ -38,6 +38,8 @@ struct Opt {
   send_pipeline: Option<String>,
   #[structopt(long)]
   recv_pipeline_participant_template: Option<String>,
+  #[structopt(short, long, parse(from_occurrences))]
+  verbose: u8,
 }
 
 #[cfg(not(target_os = "macos"))]
@@ -70,10 +72,14 @@ fn main() {
 }
 
 async fn main_inner() -> Result<()> {
-  init_tracing();
-
   let opt = Opt::from_args();
 
+  init_tracing(match opt.verbose {
+    0 => tracing::Level::INFO,
+    1 => tracing::Level::DEBUG,
+    _ => tracing::Level::TRACE,
+  });
+
   glib::log_set_default_handler(glib::rust_log_handler);
   let main_loop = glib::MainLoop::new(None, false);
   gstreamer::init().unwrap();
@@ -189,6 +195,15 @@ async fn main_inner() -> Result<()> {
       })
     })
     .await;
+  
+  conference
+    .on_participant_left(move |participant| {
+      Box::pin(async move {
+        info!("Participant left: {:?}", participant);
+        Ok(())
+      })
+    })
+    .await;
 
   conference
     .set_pipeline_state(gstreamer::State::Playing)
@@ -215,9 +230,9 @@ async fn main_inner() -> Result<()> {
   Ok(())
 }
 
-fn init_tracing() {
+fn init_tracing(level: tracing::Level) {
   tracing_subscriber::fmt()
-    .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
+    .with_max_level(level)
     .with_span_events(tracing_subscriber::fmt::format::FmtSpan::CLOSE)
     .with_target(false)
     .init();
diff --git a/lib-gst-meet/src/conference.rs b/lib-gst-meet/src/conference.rs
index 4cd490e..46772b8 100644
--- a/lib-gst-meet/src/conference.rs
+++ b/lib-gst-meet/src/conference.rs
@@ -104,6 +104,7 @@ pub(crate) struct JitsiConferenceInner {
         + Sync,
     >,
   >,
+  on_participant_left: Option<Arc<dyn (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<()>> + Send>>) + Send + Sync>>,
   state: JitsiConferenceState,
   connected_tx: Option<oneshot::Sender<()>>,
   connected_rx: Option<oneshot::Receiver<()>>,
@@ -137,6 +138,7 @@ impl JitsiConference {
         state: JitsiConferenceState::Discovering,
         participants: HashMap::new(),
         on_participant: None,
+        on_participant_left: None,
         jingle_session: None,
         connected_tx: Some(tx),
         connected_rx: Some(rx),
@@ -316,6 +318,17 @@ impl JitsiConference {
       }
     }
   }
+
+  #[tracing::instrument(level = "trace", skip(f))]
+  pub async fn on_participant_left(
+    &self,
+    f: impl (Fn(Participant) -> Pin<Box<dyn Future<Output = Result<()>> + Send>>)
+    + Send
+    + Sync
+    + 'static,
+  ) {
+    self.inner.lock().await.on_participant_left = Some(Arc::new(f));
+  }
 }
 
 #[async_trait]
@@ -560,6 +573,16 @@ 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/lib-gst-meet/src/jingle.rs b/lib-gst-meet/src/jingle.rs
index 31e1ed4..52f5eb6 100644
--- a/lib-gst-meet/src/jingle.rs
+++ b/lib-gst-meet/src/jingle.rs
@@ -311,8 +311,8 @@ impl JingleSession {
       }
     }
 
-    ice_agent.connect_candidate_gathering_done(move |ice_agent, a| {
-      debug!("ICE candidate-gathering-done {}", a);
+    ice_agent.connect_candidate_gathering_done(move |_agent, candidates| {
+      debug!("ICE candidate-gathering-done {:?}", candidates);
     });
 
     debug!("gathering ICE candidates");
diff --git a/shell.nix b/shell.nix
index e42b228..11040dd 100644
--- a/shell.nix
+++ b/shell.nix
@@ -5,6 +5,12 @@ mkShell {
     pkg-config
     glib
     gst_all_1.gstreamer
+    gst_all_1.gst-plugins-base
+    gst_all_1.gst-plugins-good
+    gst_all_1.gst-plugins-bad
     libnice
-  ];
+  ] ++ (if stdenv.isDarwin then [
+    darwin.apple_sdk.frameworks.AppKit
+    darwin.apple_sdk.frameworks.Security
+  ] else []);
 }