From 4e717815c78650b78c10b0d251ebb56ac92eaef1 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <mo@bunkus.online>
Date: Sat, 13 Mar 2021 00:12:02 +0100
Subject: [PATCH] GUI: mux: derive track languages from file names case
 insensitively

Fixes #3068.
---
 NEWS.md                                  | 3 +++
 src/mkvtoolnix-gui/merge/source_file.cpp | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 93f9e9b3d..9315082c8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -17,6 +17,9 @@
 * mkvinfo: when compiled with newer versions of the `fmt` library, certain
   numbers were not output correctly (e.g. a track's audio sampling frequency
   of 48000 might be output as 48).
+* MKVToolNix GUI: multiplexer: deriving the track language from the file name
+  will match languages case insensitively again (like versions prior to
+  v55). Fixes #3068.
 
 ## Build system changes
 
diff --git a/src/mkvtoolnix-gui/merge/source_file.cpp b/src/mkvtoolnix-gui/merge/source_file.cpp
index a8ffb780e..115f612e3 100644
--- a/src/mkvtoolnix-gui/merge/source_file.cpp
+++ b/src/mkvtoolnix-gui/merge/source_file.cpp
@@ -356,8 +356,8 @@ SourceFile::setupProgramMapFromProperties() {
 mtx::bcp47::language_c
 SourceFile::deriveLanguageFromFileName() {
   auto &cfg     = Util::Settings::get();
-  auto fileName = QFileInfo{m_fileName}.fileName();
-  auto matches  = QRegularExpression{Q("s\\d+e\\d{2,}(.+)"), QRegularExpression::CaseInsensitiveOption}.match(fileName);
+  auto fileName = QFileInfo{m_fileName}.fileName().toLower();
+  auto matches  = QRegularExpression{Q("s\\d+e\\d{2,}(.+)")}.match(fileName);
 
   if (matches.hasMatch()) {
     fileName = matches.captured(1);