Merge pull request #88 from Maxr1998/limit-line-time

Don't parse word time tags if multiple line times are present

Author: andy840119

LrcParser.Tests/Parser/Lrc/Lines/LrcLyricParserTest.cs

@@ -105,6 +105,17 @@ public void TestDecode(string lyric, LrcLyric expected)
                 TimeTags = [],
             },
         ],
+        // Don't parse word time tags if multiple line time tags are found, as this is unsupported by LRC.
+        // Instead, return the unparsed line without the line time and no word time tags.
+        [
+            "[00:17.00][00:18.00] <00:00.00>帰<00:01.00>り<00:02.00>道<00:03.00>は",
+            new LrcLyric
+            {
+                Text = "<00:00.00>帰<00:01.00>り<00:02.00>道<00:03.00>は",
+                StartTimes = [17000, 18000],
+                TimeTags = [],
+            },
+        ],
     };
 
     [TestCaseSource(nameof(testEncodeSource))]

LrcParser/Parser/Lrc/Lines/LrcLyricParser.cs

@@ -1,6 +1,7 @@
 // Copyright (c) karaoke.dev <contact@karaoke.dev>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using LrcParser.Model;
 using LrcParser.Parser.Lines;
 using LrcParser.Parser.Lrc.Metadata;
 using LrcParser.Parser.Lrc.Utils;
@@ -14,8 +15,28 @@ public override bool CanDecode(string text)
 
     public override LrcLyric Decode(string text)
     {
-        var (startTimes, lyricText) = LrcStartTimeUtils.SplitLyricAndTimeTag(text);
-        var (lyric, timeTags) = LrcTimedTextUtils.TimedTextToObject(lyricText);
+        var (startTimes, rawLyric) = LrcStartTimeUtils.SplitLyricAndTimeTag(text);
+
+        // If there are multiple start times, it is possible that the given word time tags are incompatible with one or more start times.
+        // For example, if a line starts at both [01:00.00] and [02:00.00],
+        // word time tags with the values <01:10.00> and <01:20.00> would be incompatible with the second start time.
+        // As there isn't an official LRC spec, this isn't clearly defined.
+        // While the format is technically valid, we chose a reasonable behavior of ignoring the word time tags in this case
+        // and returning the line as-is without parsing the word time tags.
+        // The same applies to lines that have no start times:
+        // As there might be lines like `Every <00:07.56> night`, the first word would not have a start time,
+        // so we chose the same approach of ignoring the word time tags in this case.
+        if (startTimes.Length is 0 or > 1)
+        {
+            return new LrcLyric
+            {
+                Text = rawLyric,
+                StartTimes = startTimes,
+                TimeTags = new SortedDictionary<TextIndex, int>()
+            };
+        }
+
+        var (lyric, timeTags) = LrcTimedTextUtils.TimedTextToObject(rawLyric);
 
         return new LrcLyric
         {