From 5fa35d0bc7e432a38f8d4a7e9214850d6edd8048 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Thu, 5 Mar 2026 18:22:02 +0100
Subject: fix off-by-one in segment timeline

---
 stream/src/dash.rs | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/stream/src/dash.rs b/stream/src/dash.rs
index bfec78c..d2adf3f 100644
--- a/stream/src/dash.rs
+++ b/stream/src/dash.rs
@@ -183,6 +183,7 @@ struct Timeline<'a>(&'a [Range<f64>]);
 impl Display for Timeline<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "<SegmentTimeline>")?;
+        let mut c = 0;
         let mut last_t = 0;
         let mut last_d = 0;
         let mut r = 0;
@@ -190,7 +191,6 @@ impl Display for Timeline<'_> {
         for seg in self.0 {
             let t = (seg.end * 1000.) as i64;
             let d = t - last_t;
-            r += 1;
             if d != last_d && last_d != 0 {
                 match (r, first) {
                     (1, true) => write!(f, r#"<S t="0" d="{last_d}" />"#)?,
@@ -199,16 +199,22 @@ impl Display for Timeline<'_> {
                     (_, false) => write!(f, r#"<S d="{last_d}" r="{r}" />"#)?,
                 }
                 first = false;
-                r = 0;
+                c += r;
+                r = 1;
+            } else {
+                r += 1;
             }
             last_t = t;
             last_d = d;
         }
-        if r > 1 {
-            write!(f, r#"<S d="{last_d}" r="{r}" />"#)?;
-        } else {
-            write!(f, r#"<S d="{last_d}" />"#)?;
+        c += r;
+        match (r, first) {
+            (1, true) => write!(f, r#"<S t="0" d="{last_d}" />"#)?,
+            (1, false) => write!(f, r#"<S d="{last_d}" />"#)?,
+            (_, true) => write!(f, r#"<S t="0" d="{last_d}" r="{r}" />"#)?,
+            (_, false) => write!(f, r#"<S d="{last_d}" r="{r}" />"#)?,
         }
+        assert_eq!(c, self.0.len());
         write!(f, "</SegmentTimeline>")?;
         Ok(())
     }
-- 
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