Add LyRiCs (LRC) support

lib/player.js

@@ -4178,25 +4178,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     if (mimeType === 'application/x-subtitle-lrc') {
       const LrcTextParser = shaka.text.LrcTextParser;
       if (LrcTextParser) {
-        const cues = LrcTextParser.getCues(data);
-        let webvttString = 'WEBVTT\n\n';
-        for (const cue of cues) {
-          const webvttTimeString = (time) => {
-            const hours = Math.floor(time / 3600);
-            const minutes = Math.floor(time / 60 % 60);
-            const seconds = Math.floor(time % 60);
-            const milliseconds = Math.floor(time * 1000 % 1000);
-            return (hours < 10 ? '0' : '') + hours + ':' +
-                (minutes < 10 ? '0' : '') + minutes + ':' +
-                (seconds < 10 ? '0' : '') + seconds + '.' +
-                (milliseconds < 100 ? (milliseconds < 10 ? '00' : '0') : '') +
-                milliseconds;
-          };
-          webvttString += webvttTimeString(cue.startTime) + ' --> ' +
-              webvttTimeString(cue.endTime) + '\n';
-          webvttString += cue.payload + '\n\n';
-        }
-        return webvttString;
+        return LrcTextParser.convertToWebVTT(data);
       } else {
         throw new shaka.util.Error(
             shaka.util.Error.Severity.CRITICAL,

lib/text/lrc_text_parser.js

@@ -14,6 +14,8 @@ goog.require('shaka.util.StringUtils');
 
 
 /**
+ * LRC file format: https://en.wikipedia.org/wiki/LRC_(file_format)
+ *
  * @implements {shaka.extern.TextParser}
  * @export
  */
@@ -31,15 +33,15 @@ shaka.text.LrcTextParser = class {
    * @export
    */
   parseMedia(data, time) {
-    return shaka.text.LrcTextParser.getCues(data);
+    return shaka.text.LrcTextParser.getCues_(data);
   }
 
   /**
    * @param {BufferSource} data
    * @return {!Array.<!shaka.extern.Cue>}
-   * @export
+   * @private
    */
-  static getCues(data) {
+  static getCues_(data) {
     const StringUtils = shaka.util.StringUtils;
     const LrcTextParser = shaka.text.LrcTextParser;
 
@@ -51,14 +53,14 @@ shaka.text.LrcTextParser = class {
 
     /** @type {!Array.<!shaka.extern.Cue>} */
     const cues = [];
-    const parts = str.split(/\r?\n/);
-    for (const part of parts) {
-      if (!part || /^\s+$/.test(part)) {
+    const lines = str.split(/\r?\n/);
+    for (const line of lines) {
+      if (!line || /^\s+$/.test(line)) {
         continue;
       }
 
       // LRC content
-      const match = LrcTextParser.lyricLine_.exec(part);
+      const match = LrcTextParser.lyricLine_.exec(line);
       if (match) {
         const startTime = LrcTextParser.parseTime_(match[1]);
         // By default we add 2 seconds of duration.
@@ -74,8 +76,7 @@ shaka.text.LrcTextParser = class {
         prevCue = cue;
         continue;
       }
-      shaka.log.warning('LrcTextParser parser encountered an unknown part.',
-          part);
+      shaka.log.warning('LrcTextParser encountered an unknown line.', line);
     }
     if (prevCue) {
       cues.push(prevCue);
@@ -95,9 +96,38 @@ shaka.text.LrcTextParser = class {
     const LrcTextParser = shaka.text.LrcTextParser;
     const match = LrcTextParser.timeFormat_.exec(string);
     const minutes = parseInt(match[1], 10);
-    const seconds = parseInt(match[2], 10);
-    const hundredthsOfSeconds = match[4] ? parseInt(match[4], 10) : 0;
-    return minutes * 60 + seconds + hundredthsOfSeconds / 100;
+    const seconds = parseInt(match[2], 10) + parseFloat(match[3]);
+    return minutes * 60 + seconds;
+  }
+
+  /**
+   * Convert a LRC input to WebVTT
+   *
+   * @param {BufferSource} data
+   * @return {string}
+   * @export
+   */
+  static convertToWebVTT(data) {
+    const LrcTextParser = shaka.text.LrcTextParser;
+    const cues = LrcTextParser.getCues_(data);
+    let webvttString = 'WEBVTT\n\n';
+    for (const cue of cues) {
+      const webvttTimeString = (time) => {
+        const hours = Math.floor(time / 3600);
+        const minutes = Math.floor(time / 60 % 60);
+        const seconds = Math.floor(time % 60);
+        const milliseconds = Math.floor(time * 1000 % 1000);
+        return (hours < 10 ? '0' : '') + hours + ':' +
+            (minutes < 10 ? '0' : '') + minutes + ':' +
+            (seconds < 10 ? '0' : '') + seconds + '.' +
+            (milliseconds < 100 ? (milliseconds < 10 ? '00' : '0') : '') +
+            milliseconds;
+      };
+      webvttString += webvttTimeString(cue.startTime) + ' --> ' +
+          webvttTimeString(cue.endTime) + '\n';
+      webvttString += cue.payload + '\n\n';
+    }
+    return webvttString;
   }
 };
 
@@ -112,7 +142,7 @@ shaka.text.LrcTextParser.lyricLine_ =
 /**
  * @const
  * @private {!RegExp}
- * @example 50t or 50.5t
+ * @example 00:12.00 or 00:12.0 or 00:12.000
  */
 shaka.text.LrcTextParser.timeFormat_ =
     /^\s*(\d+):(\d{1,2})([.,](\d{1,3}))?\s*$/;

test/text/lrc_text_parser_unit.js

@@ -58,6 +58,19 @@ describe('LrcTextParser', () => {
         {periodStart: 0, segmentStart: 0, segmentEnd: 0});
   });
 
+  it('supports different time formats', () => {
+    verifyHelper(
+        [
+          {startTime: 0.1, endTime: 10.001, payload: 'Test'},
+          {startTime: 10.001, endTime: 20.02, payload: 'Test2'},
+          {startTime: 20.02, endTime: 22.02, payload: 'Test3'},
+        ],
+        '[00:00.10]Test\n' +
+        '[00:10.001]Test2\n' +
+        '[00:20.02]Test3',
+        {periodStart: 0, segmentStart: 0, segmentEnd: 0});
+  });
+
   /**
    * @param {!Array} cues
    * @param {string} text