From 6e3c1874936b767754cd9267749f35b27f2ae65f Mon Sep 17 00:00:00 2001 From: Piotr Niełacny Date: Wed, 15 Jul 2026 14:55:55 +0200 Subject: Fix race condition in concurrent subtitle conversion SubtitleEncoder.ConvertSubtitles parsed subtitles with libse's static Subtitle.Parse, which iterates a statically cached list of shared SubtitleFormat instances. Format parsers keep mutable per-parse state on the instance, so concurrent subtitle requests corrupted each other's output (cues mixed across streams and languages, truncated files) or failed with NullReferenceException when format detection broke down and Subtitle.Parse returned null. Parse through the injected ISubtitleParser instead. SubtitleEditParser instantiates a fresh format parser per call, so requests no longer share state. Its Parse method now returns the libse Subtitle directly (the SubtitleTrackInfo flattening was unused since the SubtitleEdit writer rework) so the writers keep full fidelity such as ASS styling. --- MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs') diff --git a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs b/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs index 5301f52e01..974dded9ea 100644 --- a/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs +++ b/MediaBrowser.MediaEncoding/Subtitles/SubtitleEncoder.cs @@ -73,7 +73,7 @@ namespace MediaBrowser.MediaEncoding.Subtitles _serverConfigurationManager = serverConfigurationManager; } - private MemoryStream ConvertSubtitles( + internal MemoryStream ConvertSubtitles( Stream stream, SubtitleInfo inputInfo, string outputFormat, @@ -81,7 +81,7 @@ namespace MediaBrowser.MediaEncoding.Subtitles long endTimeTicks, bool preserveOriginalTimestamps) { - var subtitle = Subtitle.Parse(stream, Path.GetExtension(inputInfo.Path)); + var subtitle = _subtitleParser.Parse(stream, inputInfo.Format); FilterEvents(subtitle, startTimeTicks, endTimeTicks, preserveOriginalTimestamps); -- cgit v1.2.3