From d880cf3cd9ee8dc55be9007f26af372ffda9d6e5 Mon Sep 17 00:00:00 2001
From: Lars Kiesow <lkiesow@uos.de>
Date: Mon, 6 May 2024 19:30:43 +0200
Subject: [PATCH] Dynamic skip threshold

The hard-coded threshold of 3s for skipping to the previous segment
instead of skipping to the start of the segment can be too long for
short videos, where visually, you are far away from the actual cut mark.

This patch fixes the problem by making this a dynamic threshold based on
the video duration with a minimum of 0.5s (guarding against a non-set
video duration) and a maximum of 3s.
---
 src/redux/videoSlice.ts | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/redux/videoSlice.ts b/src/redux/videoSlice.ts
index 910d3e990..82a9618bb 100644
--- a/src/redux/videoSlice.ts
+++ b/src/redux/videoSlice.ts
@@ -150,14 +150,18 @@ const videoSlice = createSlice({
     jumpToPreviousSegment: state => {
       let previousSegmentIndex = state.activeSegmentIndex - 1;
 
-      // Jump to start of active segment if current time is in interval [start + 3s, end)
-      if (state.currentlyAt >= state.segments[state.activeSegmentIndex].start + 3000) {
+      // Calculate the threshold for “being on a cut mark”.
+      // It is based on the video length, but in between 0.5s and 3.0s.
+      const threshold = Math.max(Math.min(state.duration / 100, 3000), 500);
+
+      // Jump to start of active segment if current time is in interval [start + threshold, end)
+      if (state.currentlyAt >= state.segments[state.activeSegmentIndex].start + threshold) {
         previousSegmentIndex = state.activeSegmentIndex;
       }
 
+      // Jump to start of first segment if we are anywhere in the first segment
       if (state.activeSegmentIndex == 0) {
-        // Jump to start of first segment
-        previousSegmentIndex = state.activeSegmentIndex;
+        previousSegmentIndex = 0;
       }
 
       updateCurrentlyAt(state, state.segments[previousSegmentIndex].start);