Pipewire: metadata listener - clear defaults when null key receivedHEADdev

According to pipewire's documentation, setting a nullptr key clears all
metadata.

Fixes: QTBUG-138197
Pick-to: 6.10
Change-Id: I2f09625a6691004f5002484739217c657b4efd19
Reviewed-by: Mikko Hallamaa <[email protected]>
Reviewed-by: Timur Pocheptsov <[email protected]>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/multimedia/pipewire/qpipewire_audiocontextmanager.cpp b/src/multimedia/pipewire/qpipewire_audiocontextmanager.cpp
index 7366032a6..df5275820 100644
--- a/src/multimedia/pipewire/qpipewire_audiocontextmanager.cpp
+++ b/src/multimedia/pipewire/qpipewire_audiocontextmanager.cpp
@@ -362,6 +362,13 @@ int QAudioContextManager::handleMetadata(const MetadataRecord &record)
 
     qDebug(lcPipewireRegistry) << "metadata:" << record.key << record.type << record.value;
 
+    if (record.key == nullptr) {
+        // "NULL clears all metadata for the subject"
+        m_deviceMonitor->setDefaultAudioSource(QAudioDeviceMonitor::NoDefaultDevice);
+        m_deviceMonitor->setDefaultAudioSink(QAudioDeviceMonitor::NoDefaultDevice);
+        return 0;
+    }
+
     auto extractName = [&]() -> std::optional<QByteArray> {
         if (record.type != "Spa:String:JSON"sv)
             return std::nullopt;