From e7c3c72970f82265ab89c3ba503bdf88d7639057 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 20 Aug 2026 23:16:31 +0000
Subject: [PATCH] Add fast path to _ts_to_seconds to avoid allocation overhead

Added a fast path to `_ts_to_seconds` in `backend/extractor.py` that parses the standard `HH:MM:SS.mmm` formatted strings directly using substring indexing and float casting. This bypasses the `.split()` and generator comprehension sequence, resulting in faster parsing for the common case, while gracefully handling other string formats via a `try...except ValueError` fallback.

Also documented this finding in `.jules/bolt.md`.

Co-authored-by: benpiper <4343814+benpiper@users.noreply.github.com>
---
 .jules/bolt.md       |  4 ++++
 backend/extractor.py | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/.jules/bolt.md b/.jules/bolt.md
index e6d39e6..7720f96 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -16,3 +16,7 @@
 ## 2024-06-28 - Optimize array lookups in high-frequency React event handlers
 **Learning:** Even if data is pre-processed/memoized (like cached `parsedTimestamps`), performing an O(N) linear search on that array inside a high-frequency event handler (like `<video onTimeUpdate>`, which fires multiple times per second) can cause UI stuttering for large arrays.
 **Action:** When searching sorted arrays (like ordered video timestamps) in high-frequency event loops, replace linear iteration loops with an O(log N) binary search to minimize main thread blocking and ensure smooth UI execution.
+
+## 2024-08-20 - Fast string parsing for predictable formats
+**Learning:** For highly predictable string formats (like standard video timestamps `HH:MM:SS.mmm`), using string splitting and generator comprehensions creates unnecessary object allocation overhead.
+**Action:** Use direct substring indexing and float casting as a fast path in Python to avoid overhead.
diff --git a/backend/extractor.py b/backend/extractor.py
index 4407b4c..2d18702 100644
--- a/backend/extractor.py
+++ b/backend/extractor.py
@@ -123,6 +123,17 @@ def _escape_drawtext(text: str) -> str:
     return text
 
 def _ts_to_seconds(ts: str) -> float:
+    # ⚡ Bolt: Fast path for standard HH:MM:SS.mmm format to avoid allocation overhead
+    try:
+        ts = ts.strip()
+        if len(ts) >= 8 and ts[2] == ':' and ts[5] == ':':
+            h = float(ts[0:2])
+            m = float(ts[3:5])
+            s = float(ts[6:])
+            return h * 3600.0 + m * 60.0 + s
+    except ValueError:
+        pass
+
     parts = ts.strip().split(':')
     return sum(float(v) * m for v, m in zip(reversed(parts), [1, 60, 3600]))