update

packages/artplayer/src/player/index.js

@@ -28,6 +28,7 @@ import autoHeightMix from './autoHeightMix';
 import themeMix from './themeMix';
 import titleMix from './titleMix';
 import exclusiveMix from './exclusiveMix';
+import subtitleOffsetMix from './subtitleOffsetMix';
 import optionInit from './optionInit';
 import eventInit from './eventInit';
 
@@ -63,6 +64,7 @@ export default class Player {
         themeMix(art);
         titleMix(art);
         exclusiveMix(art);
+        subtitleOffsetMix(art);
         eventInit(art);
         optionInit(art);
     }

packages/artplayer/src/player/subtitleOffsetMix.js

@@ -0,0 +1,39 @@
+import { def } from '../utils';
+
+export default function subtitleOffsetMix(art) {
+    const { clamp } = art.constructor.utils;
+    const { notice, template, i18n, subtitle } = art;
+
+    let cuesCache = [];
+    art.on('subtitle:switch', () => {
+        cuesCache = [];
+    });
+
+    def(art, 'subtitleOffset', {
+        set(value) {
+            if (template.$track && template.$track.track) {
+                const cues = Array.from(template.$track.track.cues);
+                const time = clamp(value, -5, 5);
+
+                for (let index = 0; index < cues.length; index++) {
+                    const cue = cues[index];
+                    if (!cuesCache[index]) {
+                        cuesCache[index] = {
+                            startTime: cue.startTime,
+                            endTime: cue.endTime,
+                        };
+                    }
+                    cue.startTime = clamp(cuesCache[index].startTime + time, 0, art.duration);
+                    cue.endTime = clamp(cuesCache[index].endTime + time, 0, art.duration);
+                }
+
+                subtitle.update();
+                notice.show = `${i18n.get('Subtitle offset time')}: ${value}s`;
+                art.emit('subtitleOffset', value);
+            } else {
+                notice.show = `${i18n.get('No subtitles found')}`;
+                art.emit('subtitleOffset', 0);
+            }
+        },
+    });
+}