[graphics/digikam] core: Move audio backend preference to a shared helper, use in Showfoto

Git commit 6122c27f1c3074eabf2a8b1270b71ff2f7faa339 by Gilles Caulier, on behalf of Mark Cockram.
Committed on 22/07/2026 at 19:42.
Pushed by cgilles into branch 'master'.

Move audio backend preference to a shared helper, use in Showfoto

Host the QT_AUDIO_BACKEND=pulseaudio default in a new
setAudioBackendEnvironment() function in digikam_globals_bundles.cpp,
next to the other per-platform environment helpers, and call it from
both the digiKam and Showfoto main functions so the Showfoto media
player gets the same complete audio output list.

M  +2    -17   core/app/main/main.cpp
M  +6    -0    core/app/utils/digikam_globals.h
M  +24   -0    core/app/utils/digikam_globals_bundles.cpp
M  +4    -0    core/showfoto/main/main.cpp

https://invent.kde.org/graphics/digikam/-/commit/6122c27f1c3074eabf2a8b1270b71ff2f7faa339

diff --git a/core/app/main/main.cpp b/core/app/main/main.cpp
index 70b1387a61..06072f608f 100644
--- a/core/app/main/main.cpp
+++ b/core/app/main/main.cpp
@@ -181,24 +181,9 @@ MAIN_EXPORT int MAIN_FN(int argc, char** argv)
 
     qputenv("QT_MEDIA_BACKEND", system.videoBackend.toLatin1());
 
-#   if defined Q_OS_LINUX
+    // Common audio backend rules from digikam_globals.
 
-    if (!qEnvironmentVariableIsSet("QT_AUDIO_BACKEND"))
-    {
-        // On PipeWire systems Qt >= 6.10 defaults to its native PipeWire
-        // audio backend, whose asynchronous format enumeration can fail
-        // for sinks owned by other PipeWire clients (for example
-        // module-filter-chain effect sinks): the affected outputs then
-        // never appear in QMediaDevices::audioOutputs(), so they are
-        // missing from the audio output selection of the media player.
-        // The PulseAudio backend enumerates the same devices through
-        // pipewire-pulse without this defect, so prefer it until the Qt
-        // issue is fixed.
-
-        qputenv("QT_AUDIO_BACKEND", "pulseaudio");
-    }
-
-#   endif
+    setAudioBackendEnvironment();
 
 #endif
 
diff --git a/core/app/utils/digikam_globals.h b/core/app/utils/digikam_globals.h
index d7c1e05213..38b46973fc 100644
--- a/core/app/utils/digikam_globals.h
+++ b/core/app/utils/digikam_globals.h
@@ -312,6 +312,12 @@ DIGIKAM_EXPORT void setMacOSEnvironment();
  */
 DIGIKAM_EXPORT void setWindowsEnvironment(QApplication& app);
 
+/**
+ * For Linux only, prefer the PulseAudio backend of Qt Multimedia if the user
+ * has not selected an audio backend explicitly with QT_AUDIO_BACKEND.
+ */
+DIGIKAM_EXPORT void setAudioBackendEnvironment();
+
 /**
  * For OpenCV framework, set necessary environment variables to use OpenCL features.
  */
diff --git a/core/app/utils/digikam_globals_bundles.cpp b/core/app/utils/digikam_globals_bundles.cpp
index c673de71a9..923ee17af0 100644
--- a/core/app/utils/digikam_globals_bundles.cpp
+++ b/core/app/utils/digikam_globals_bundles.cpp
@@ -583,6 +583,30 @@ void setWindowsEnvironment(QApplication& app)
 
 }
 
+void setAudioBackendEnvironment()
+{
+
+#if defined(Q_OS_LINUX) && (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+
+    if (!qEnvironmentVariableIsSet("QT_AUDIO_BACKEND"))
+    {
+        // On PipeWire systems Qt >= 6.10 defaults to its native PipeWire
+        // audio backend, whose asynchronous format enumeration can fail
+        // for sinks owned by other PipeWire clients (for example
+        // module-filter-chain effect sinks): the affected outputs then
+        // never appear in QMediaDevices::audioOutputs(), so they are
+        // missing from the audio output selection of the media player
+        // (QTBUG-143570). The PulseAudio backend enumerates the same
+        // devices through pipewire-pulse without this defect, so prefer
+        // it until the Qt issue is fixed.
+
+        qputenv("QT_AUDIO_BACKEND", "pulseaudio");
+    }
+
+#endif
+
+}
+
 void delayForRemoteDebuging(int delaySecs)
 {
     const QByteArray remoteDebug = qgetenv("DIGIKAM_REMOTE_DEBUG");
diff --git a/core/showfoto/main/main.cpp b/core/showfoto/main/main.cpp
index 73f29ab459..ff9b4c6297 100644
--- a/core/showfoto/main/main.cpp
+++ b/core/showfoto/main/main.cpp
@@ -156,6 +156,10 @@ MAIN_EXPORT int MAIN_FN(int argc, char** argv)
 
     qputenv("QT_MEDIA_BACKEND", system.videoBackend.toLatin1());
 
+    // Common audio backend rules from digikam_globals.
+
+    setAudioBackendEnvironment();
+
 #endif
 
 #if defined HAVE_KICONTHEMES && (KICONTHEMES_VERSION >= QT_VERSION_CHECK(6, 3, 0))