Use SubtitleEdit to parse subtitles

tests/Jellyfin.MediaEncoding.Tests/Subtitles/SsaParserTests.cs

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+using System;
+using System.Globalization;
+using System.IO;
+using System.Threading;
+using MediaBrowser.MediaEncoding.Subtitles;
+using Xunit;
+
+namespace Jellyfin.MediaEncoding.Subtitles.Tests
+{
+    public class SsaParserTests
+    {
+        [Fact]
+        public void Parse_Valid_Success()
+        {
+            using (var stream = File.OpenRead("Test Data/example.ssa"))
+            {
+                var parsed = new SsaParser().Parse(stream, CancellationToken.None);
+                Assert.Single(parsed.TrackEvents);
+                var trackEvent = parsed.TrackEvents[0];
+
+                Assert.Equal("1", trackEvent.Id);
+                Assert.Equal(TimeSpan.Parse("00:00:01.18", CultureInfo.InvariantCulture).Ticks, trackEvent.StartPositionTicks);
+                Assert.Equal(TimeSpan.Parse("00:00:06.85", CultureInfo.InvariantCulture).Ticks, trackEvent.EndPositionTicks);
+                Assert.Equal("{\\pos(400,570)}Like an angel with pity on nobody", trackEvent.Text);
+            }
+        }
+    }
+}