From 3ac4c54c1a05ef499d9303e88aba88270d40cfb7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?A=CC=81lvaro=20Velad=20Galva=CC=81n?= <ladvan91@hotmail.com>
Date: Thu, 30 Jan 2025 11:31:22 +0100
Subject: [PATCH 1/2] fix: Fixed displaying subtitles in UITextDisplayer at
 high playback rates

---
 lib/text/ui_text_displayer.js | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/lib/text/ui_text_displayer.js b/lib/text/ui_text_displayer.js
index b0217d37ed..167414c3c0 100644
--- a/lib/text/ui_text_displayer.js
+++ b/lib/text/ui_text_displayer.js
@@ -55,6 +55,9 @@ shaka.text.UITextDisplayer = class {
     /** @private {?number} */
     this.aspectRatio_ = null;
 
+    /** @private {?shaka.extern.TextDisplayerConfiguration} */
+    this.config_ = null;
+
     /** @type {HTMLElement} */
     this.textContainer_ = shaka.util.Dom.createHTMLElement('div');
     this.textContainer_.classList.add('shaka-text-container');
@@ -77,7 +80,8 @@ shaka.text.UITextDisplayer = class {
       if (!this.video_.paused) {
         this.updateCaptions_();
       }
-    }).tickEvery(/* seconds= */ 0.25);
+    });
+    this.configureCaptionsTimer_();
 
     /**
      * Maps cues to cue elements. Specifically points out the wrapper element of
@@ -101,6 +105,10 @@ shaka.text.UITextDisplayer = class {
       this.updateCaptions_(/* forceUpdate= */ true);
     });
 
+    this.eventManager_.listen(this.video_, 'ratechange', () => {
+      this.configureCaptionsTimer_();
+    });
+
     // From: https://html.spec.whatwg.org/multipage/media.html#dom-video-videowidth
     // Whenever the natural width or natural height of the video changes
     // (including, for example, because the selected video track was changed),
@@ -137,9 +145,8 @@ shaka.text.UITextDisplayer = class {
    * @export
    */
   configure(config) {
-    if (this.captionsTimer_) {
-      this.captionsTimer_.tickEvery(config.captionsUpdatePeriod);
-    }
+    this.config_ = config;
+    this.configureCaptionsTimer_();
   }
 
 
@@ -186,6 +193,7 @@ shaka.text.UITextDisplayer = class {
     this.cues_ = [];
     if (this.captionsTimer_) {
       this.captionsTimer_.stop();
+      this.captionsTimer_ = null;
     }
 
     this.currentCuesMap_.clear();
@@ -265,6 +273,19 @@ shaka.text.UITextDisplayer = class {
   enableTextDisplayer() {
   }
 
+  /**
+   * @private
+   */
+  configureCaptionsTimer_() {
+    if (this.captionsTimer_) {
+      const captionsUpdatePeriod = this.config_ ?
+          this.config_.captionsUpdatePeriod : 0.25;
+      const updateTime =
+          captionsUpdatePeriod / Math.max(1, this.video_.playbackRate);
+      this.captionsTimer_.tickEvery(updateTime);
+    }
+  }
+
   /**
    * @private
    */

From 01a8163f4a640f7ec7bcf662daa9e5c9fe07ddd7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?A=CC=81lvaro=20Velad=20Galva=CC=81n?= <ladvan91@hotmail.com>
Date: Thu, 30 Jan 2025 12:11:43 +0100
Subject: [PATCH 2/2] Add Math.abs

---
 lib/text/ui_text_displayer.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/text/ui_text_displayer.js b/lib/text/ui_text_displayer.js
index 167414c3c0..1fe4add63c 100644
--- a/lib/text/ui_text_displayer.js
+++ b/lib/text/ui_text_displayer.js
@@ -280,8 +280,8 @@ shaka.text.UITextDisplayer = class {
     if (this.captionsTimer_) {
       const captionsUpdatePeriod = this.config_ ?
           this.config_.captionsUpdatePeriod : 0.25;
-      const updateTime =
-          captionsUpdatePeriod / Math.max(1, this.video_.playbackRate);
+      const updateTime = captionsUpdatePeriod /
+          Math.max(1, Math.abs(this.video_.playbackRate));
       this.captionsTimer_.tickEvery(updateTime);
     }
   }