From 49510e7d5a4b341a92ff962d0808bea3d5a0bfc8 Mon Sep 17 00:00:00 2001
From: Daniel <790119+DanTheMan827@users.noreply.github.com>
Date: Sat, 4 Apr 2026 01:01:41 -0500
Subject: [PATCH] Move MPEG check to end of content-based detection (#1319)

MPEG::File::isSupported() scans for frame sync bytes that can appear
in other files, causing them to be misidentified as MP3.

This also includes a test with such a file.
---
 taglib/fileref.cpp             |   5 +++--
 tests/data/mpeg-sync-flac.flac | Bin 0 -> 834 bytes
 tests/test_fileref_detect.cpp  |   4 ++++
 3 files changed, 7 insertions(+), 2 deletions(-)
 create mode 100644 tests/data/mpeg-sync-flac.flac

diff --git a/taglib/fileref.cpp b/taglib/fileref.cpp
index a8c3404f..e0284c6a 100644
--- a/taglib/fileref.cpp
+++ b/taglib/fileref.cpp
@@ -246,8 +246,7 @@ namespace
   {
     File *file = nullptr;
 
-    if(MPEG::File::isSupported(stream))
-      file = new MPEG::File(stream, readAudioProperties, audioPropertiesStyle);
+    if(false);
 #ifdef TAGLIB_WITH_VORBIS
     else if(Ogg::Vorbis::File::isSupported(stream))
       file = new Ogg::Vorbis::File(stream, readAudioProperties, audioPropertiesStyle);
@@ -300,6 +299,8 @@ namespace
     else if(Matroska::File::isSupported(stream))
       file = new Matroska::File(stream, readAudioProperties, audioPropertiesStyle);
 #endif
+    else if(MPEG::File::isSupported(stream))
+      file = new MPEG::File(stream, readAudioProperties, audioPropertiesStyle);
 
     // isSupported() only does a quick check, so double check the file here.
 
diff --git a/tests/data/mpeg-sync-flac.flac b/tests/data/mpeg-sync-flac.flac
new file mode 100644
index 0000000000000000000000000000000000000000..6b92aae902e9c752a078285f59d343ff50553cf1
GIT binary patch
literal 834
zcmY+>T}YF06bA7Bw3c7Fx4Gt<Zq{b|(9N9rg$O1p#43bZUzCPp>XL|Vy6Qq0YGo<1
zKnVmbC`1H{!D845T8WG$c@aciNJ2<-p`s&}D02_bl@A9FzlU>ox-Yn!g%CzbNU4>Z
znyk-F8zQ|&-1e;mUv;}X&t8lcMxL!s^a-I(o$QMwl8LA+A}m8|kYb)HABWPuP+A3)
z9;1Bsp##fQS2c9-2esJ<DVM0&Pw3Ehs_hMwu}$^0Lz%mj#tLP{sj>i+y+zF}Ksl?_
zt%uOz6)L&~<^G{IdLY$0<<&t_fcp9vIufL=??UP@<@Q2(@2P)kNHa^RUC_~KYQPL>
zUr^yNls`q;qLBQAiq}KOhAB@gRM1b|_y!fGo`NjCgmhz6$uCInr#_5AMbD{6D(Ltm
zB|U&n7^$m9$Y7#AUW1HwDzOL^+o*dX=wt)+^gm>(qjW=%*+H4KkfoLicpz&5b=MD-
z=&9}BP^pIc)C<}2sLR=qT}iz?2bC!(%NgiY237PLDpyg1OOWFdWoUsau2AnPpwn&C
f$P83@laiOAs#a=e5~_Amcm5_5PPyhh<?7f2q_zS>

literal 0
HcmV?d00001

diff --git a/tests/test_fileref_detect.cpp b/tests/test_fileref_detect.cpp
index 837c82fb..a5e74804 100644
--- a/tests/test_fileref_detect.cpp
+++ b/tests/test_fileref_detect.cpp
@@ -167,6 +167,7 @@ class TestFileRefDetectByContent : public CppUnit::TestFixture
   CPPUNIT_TEST(testSilence44SFlac);
   CPPUNIT_TEST(testSinewaveFlac);
   CPPUNIT_TEST(testZeroSizedPaddingFlac);
+  CPPUNIT_TEST(testFLACWithMPEGSyncBytes);
   // Ogg::Speex::File
   CPPUNIT_TEST(testEmptySpx);
   // Ogg::Opus::File
@@ -326,6 +327,9 @@ public:
   void testZeroSizedPaddingFlac() {
     detectByContent<FLAC::File>("zero-sized-padding.flac");
   }
+  void testFLACWithMPEGSyncBytes() {
+    detectByContent<FLAC::File>("mpeg-sync-flac.flac");
+  }
 
   // -- Ogg::Speex::File --
   void testEmptySpx() { detectByContent<Ogg::Speex::File>("empty.spx"); }