diff --git a/server/src/media/source.rs b/server/src/media/source.rs
index 45320b1..6566f6a 100644
--- a/server/src/media/source.rs
+++ b/server/src/media/source.rs
@@ -8,14 +8,17 @@ use mp4::ReadBox;
 
 pub struct Source {
     reader: io::BufReader<fs::File>,
-    start: time::Instant,
     pending: Option<Fragment>,
+
+    start: time::Instant,
+    timescale: Option<u64>,
 }
 
 pub struct Fragment {
+    pub typ: mp4::BoxType,
     pub data: Vec<u8>,
     pub keyframe: bool,
-    pub timestamp: u64, // only used to simulate a live stream
+    pub timestamp: Option<u64>, // only used to simulate a live stream
 }
 
 impl Source {
@@ -28,46 +31,66 @@ impl Source {
             reader,
             start,
             pending: None,
+            timescale: None,
         })
     }
 
     pub fn next(&mut self) -> anyhow::Result<Option<Fragment>> {
-        let pending = match self.pending.take() {
-            Some(f) => f,
-            None => self.next_inner()?,
+        if self.pending.is_none() {
+            self.pending = Some(self.next_inner()?);
         };
 
-        if pending.timestamp > 0 && pending.timestamp < self.start.elapsed().as_millis() as u64 {
-            self.pending = Some(pending);
+        if self.timeout().is_some() {
             return Ok(None)
         }
 
-        Ok(Some(pending))
+        let pending = self.pending.take();
+        Ok(pending)
     }
 
     fn next_inner(&mut self) -> anyhow::Result<Fragment> {
         // Read the next full atom.
         let atom = read_box(&mut self.reader)?;
-        let mut timestamp = 0;
+        let mut timestamp = None;
         let mut keyframe = false;
 
         // Before we return it, let's do some simple parsing.
         let mut reader = io::Cursor::new(&atom);
         let header = mp4::BoxHeader::read(&mut reader)?;
 
-        if header.name == mp4::BoxType::MoofBox {
-            let moof = mp4::MoofBox::read_box(&mut reader, header.size)?;
+        match header.name {
+            mp4::BoxType::MoovBox => {
+                // We need to parse the moov to get the timescale.
+                let moov = mp4::MoovBox::read_box(&mut reader, header.size)?;
+                self.timescale = Some(moov.traks[0].mdia.mdhd.timescale.into());
+            },
+            mp4::BoxType::MoofBox => {
+                let moof = mp4::MoofBox::read_box(&mut reader, header.size)?;
 
-            keyframe = has_keyframe(&moof);
-            timestamp = first_timestamp(&moof);
+                keyframe = has_keyframe(&moof);
+                timestamp = first_timestamp(&moof);
+            }
+            _ => {},
         }
 
         Ok(Fragment {
+            typ: header.name,
             data: atom,
             keyframe,
             timestamp,
         })
     }
+
+    // Simulate a live stream by sleeping until the next timestamp in the media.
+    pub fn timeout(&self) -> Option<time::Duration> {
+        let timestamp = self.pending.as_ref()?.timestamp?;
+        let timescale = self.timescale?;
+
+        let delay = time::Duration::from_millis(1000 * timestamp / timescale);
+        let elapsed = self.start.elapsed();
+
+        delay.checked_sub(elapsed)
+    }
 }
 
 // Read a full MP4 atom into a vector.
@@ -139,16 +162,6 @@ fn has_keyframe(moof: &mp4::MoofBox) -> bool {
     false
 }
 
-fn first_timestamp(moof: &mp4::MoofBox) -> u64 {
-    let traf = match moof.trafs.first() {
-        Some(t) => t,
-        None => return 0,
-    };
-
-    let tfdt = match &traf.tfdt {
-        Some(t) => t,
-        None => return 0,
-    };
-
-    tfdt.base_media_decode_time
+fn first_timestamp(moof: &mp4::MoofBox) -> Option<u64> {
+    Some(moof.trafs.first()?.tfdt.as_ref()?.base_media_decode_time)
 }
diff --git a/server/src/session/message.rs b/server/src/session/message.rs
index 314660a..8718b81 100644
--- a/server/src/session/message.rs
+++ b/server/src/session/message.rs
@@ -14,7 +14,6 @@ pub struct Init {
 #[derive(Serialize, Deserialize)]
 pub struct Segment {
     pub init: String,
-	pub timestamp: u64,
 }
 
 impl Message {
diff --git a/server/src/session/session.rs b/server/src/session/session.rs
index d694956..9edd481 100644
--- a/server/src/session/session.rs
+++ b/server/src/session/session.rs
@@ -6,10 +6,13 @@ use quiche::h3::webtransport;
 use crate::{media,transport};
 use super::message;
 
+use mp4;
+
 #[derive(Default)]
 pub struct Session {
     media: Option<media::Source>,
     stream_id: Option<u64>, // stream ID of the current segment
+    styp: Option<Vec<u8>>,
 }
 
 impl transport::App for Session {
@@ -58,7 +61,7 @@ impl transport::App for Session {
     }
 
     fn timeout(&self) -> Option<time::Duration> {
-        None
+        self.media.as_ref().and_then(|m| m.timeout())
     }
 }
 
@@ -74,8 +77,6 @@ impl Session {
             None => return Ok(()),
         };
 
-        log::debug!("{} {}", fragment.keyframe, fragment.timestamp);
-
         let mut stream_id = match self.stream_id {
             Some(stream_id) => stream_id,
             None => {
@@ -101,7 +102,6 @@ impl Session {
             let mut message = message::Message::new();
             message.segment = Some(message::Segment{
                 init: "video".to_string(),
-                timestamp: fragment.timestamp,
             });
 
             let data = message.serialize()?;
@@ -111,18 +111,30 @@ impl Session {
             // TODO handle when stream is full
             stream_id = session.open_stream(conn, false)?;
             session.send_stream_data(conn, stream_id, data.as_slice())?;
+
+            let styp = self.styp.as_ref().expect("missing ftyp mox");
+            session.send_stream_data(conn, stream_id, &styp)?;
         }
 
         let data = fragment.data.as_slice();
 
         // TODO check if stream is writable
-        session.send_stream_data(conn, stream_id, data)?;
-
-        log::debug!("wrote {} to {}", std::str::from_utf8(&data[4..8]).unwrap(), stream_id);
+        let size = session.send_stream_data(conn, stream_id, data)?;
+        if size < data.len() {
+            anyhow::bail!("partial write: {} < {}", size, data.len());
+        }
 
         // Save for the next fragment
         self.stream_id = Some(stream_id);
 
+        // Save the ftyp fragment but modify it to be a styp for furture segments.
+        if fragment.typ == mp4::BoxType::FtypBox {
+            let mut data = fragment.data;
+            data[4] = b's'; // ftyp to styp
+
+            self.styp = Some(data);
+        }
+
         Ok(())
     }
 }
\ No newline at end of file