完美版本

youtube_sub.js

@@ -361,7 +361,7 @@ GM_addStyle(`
                     if (!data?.events) {
                         throw new Error('Invalid subtitle data format');
                     }
-                    debugger;
+                    //debugger;
                     const subtitles = data.events
                         .filter(event => event.segs && event.tStartMs !== undefined)
                         .map(event => ({
@@ -636,31 +636,47 @@ GM_addStyle(`
         }
 
 
+
         setupVideoTimeUpdate() {
             let rafId = null;
-            const updateThreshold = 16; // ~60fps
+            const updateThreshold = 16;
             let lastUpdate = 0;
-
-            const findSubtitleIndex = (time, subtitles) => {
-                // Binary search for faster lookup
-                let start = 0;
-                let end = subtitles.length - 1;
-
-                while (start <= end) {
-                    const mid = Math.floor((start + end) / 2);
-                    const sub = subtitles[mid];
-
-                    if (time >= sub.startTime && time <= sub.endTime) {
-                        return mid;
+            const TRANSITION_BUFFER = 0.1; // 100ms buffer
+            let lastActiveIndex = -1;
+
+            const findActiveSubtitle = (time, subtitles) => {
+                // Find all potentially active subtitles
+                const active = [];
+
+                for (let i = 0; i < subtitles.length; i++) {
+                    const sub = subtitles[i];
+                    // Add buffer for smoother transitions
+                    if (time >= (sub.startTime - TRANSITION_BUFFER) &&
+                        time <= (sub.endTime + TRANSITION_BUFFER)) {
+                        active.push({ index: i, sub });
                     }
+                    // Early exit if we're past the current time
+                    if (sub.startTime > time + 1) break;
+                }
 
-                    if (time < sub.startTime) {
-                        end = mid - 1;
-                    } else {
-                        start = mid + 1;
-                    }
+                if (active.length === 0) return -1;
+
+                // If multiple subtitles are active, choose the most relevant one
+                if (active.length > 1) {
+                    // Prefer subtitle that has just started
+                    const justStarted = active.find(({ sub }) =>
+                        Math.abs(time - sub.startTime) < TRANSITION_BUFFER);
+                    if (justStarted) return justStarted.index;
+
+                    // Otherwise use the one with the closest start time
+                    return active.reduce((prev, curr) => {
+                        const prevDiff = Math.abs(time - prev.sub.startTime);
+                        const currDiff = Math.abs(time - curr.sub.startTime);
+                        return currDiff < prevDiff ? curr : prev;
+                    }).index;
                 }
-                return -1;
+
+                return active[0].index;
             };
 
             const handleTimeUpdate = (video) => {
@@ -675,28 +691,28 @@ GM_addStyle(`
                 const subtitles = this.currentTab === 'chinese' ?
                     this.subtitles.chinese : this.subtitles.english;
 
-                const newIndex = findSubtitleIndex(currentTime, subtitles);
-                if (newIndex === this.subtitleIndex) {
+                const newIndex = findActiveSubtitle(currentTime, subtitles);
+                if (newIndex === lastActiveIndex) {
                     rafId = requestAnimationFrame(() => handleTimeUpdate(video));
                     return;
                 }
 
-                this.subtitleIndex = newIndex;
                 const lines = this.container.querySelectorAll('.subtitle-line');
-
                 lines.forEach(line => {
                     const lineIndex = parseInt(line.dataset.index);
                     const isActive = lineIndex === newIndex;
 
                     line.classList.toggle('active', isActive);
-                    if (isActive) {
+                    if (isActive && lineIndex !== lastActiveIndex) {
+                        // Smooth scroll for new active subtitle
                         line.scrollIntoView({
                             block: 'center',
-                            behavior: 'auto'
+                            behavior: 'smooth'
                         });
                     }
                 });
 
+                lastActiveIndex = newIndex;
                 rafId = requestAnimationFrame(() => handleTimeUpdate(video));
             };
 
@@ -760,7 +776,7 @@ GM_addStyle(`
 
             //enter debug mode
 
-            debugger;
+            //debugger;
 
             // 3. Load subtitle data
             for (const track of tracks) {