[multimedia/kdenlive] src: Autodetect transparency in clip monitor to add compositing when useful

Git commit aad6a47c335c0da991662d96adf1128ca2511f99 by Jean-Baptiste Mardelle.
Committed on 18/08/2026 at 09:29.
Pushed by mardelle into branch 'master'.

Autodetect transparency in clip monitor to add compositing when useful
Fixes #2226

M  +1    -1    src/bin/playlistclip.cpp
M  +1    -1    src/bin/playlistclip.h
M  +17   -11   src/bin/projectclip.cpp
M  +1    -1    src/bin/projectclip.h
M  +1    -1    src/monitor/monitor.cpp

https://invent.kde.org/multimedia/kdenlive/-/commit/aad6a47c335c0da991662d96adf1128ca2511f99

diff --git a/src/bin/playlistclip.cpp b/src/bin/playlistclip.cpp
index 2005c7348d..790564380d 100644
--- a/src/bin/playlistclip.cpp
+++ b/src/bin/playlistclip.cpp
@@ -421,7 +421,7 @@ const QString PlaylistClip::getPlaylistRoot()
     return m_playlistRoot;
 }
 
-bool PlaylistClip::hasAlpha()
+bool PlaylistClip::hasAlpha() const
 {
     if (clipUrl().isEmpty()) {
         return false;
diff --git a/src/bin/playlistclip.h b/src/bin/playlistclip.h
index 09b08c47c1..1bc6672706 100644
--- a/src/bin/playlistclip.h
+++ b/src/bin/playlistclip.h
@@ -61,7 +61,7 @@ public:
     static std::shared_ptr<PlaylistClip> construct(const QString &id, const QDomElement &description, const QIcon &thumb,
                                                    std::shared_ptr<ProjectItemModel> model);
     /** @brief returns true if an avformat producer has an alpha channel */
-    bool hasAlpha() override;
+    bool hasAlpha() const override;
 
 protected:
     PlaylistClip(const QString &id, const QIcon &thumb, const std::shared_ptr<ProjectItemModel> &model, std::shared_ptr<Mlt::Producer> &producer);
diff --git a/src/bin/projectclip.cpp b/src/bin/projectclip.cpp
index 2a253d5703..b641445956 100644
--- a/src/bin/projectclip.cpp
+++ b/src/bin/projectclip.cpp
@@ -3222,19 +3222,25 @@ size_t ProjectClip::sequenceFrameDuration(const QUuid &)
     return frameDuration();
 }
 
-bool ProjectClip::hasAlpha()
-{
-    const QStringList alphaFormats = {QLatin1String("argb"), QLatin1String("abgr"), QLatin1String("bgra"), QLatin1String("rgba"),
-                                      QLatin1String("gbra"), QLatin1String("yuva"), QLatin1String("ya")};
-    int vindex = m_properties->get_int("video_index");
-    const QString codecInfo = QStringLiteral("meta.media.%1.codec.pix_fmt").arg(vindex);
-    const QString selected = getProducerProperty(codecInfo);
-    if (selected.isEmpty()) {
+bool ProjectClip::hasAlpha() const
+{
+    if (m_clipType == ClipType::Audio || m_clipType == ClipType::Color || m_clipType == ClipType::Timeline) {
         return false;
     }
-    for (auto &f : alphaFormats) {
-        if (selected.startsWith(f)) {
-            return true;
+    if (m_clipType == ClipType::Text || m_clipType == ClipType::TextTemplate || m_clipType == ClipType::Image || m_clipType == ClipType::Animation) {
+        return true;
+    }
+    if (m_clipType == ClipType::AV || m_clipType == ClipType::Video) {
+        const QStringList alphaFormats = {QLatin1String("argb"), QLatin1String("abgr"), QLatin1String("bgra"), QLatin1String("rgba"),
+                                          QLatin1String("gbra"), QLatin1String("yuva"), QLatin1String("ya")};
+        const QString codecInfo = videoCodecProperty(QStringLiteral("pix_fmt"));
+        if (codecInfo.isEmpty() || !codecInfo.contains(QLatin1Char('a'))) {
+            return false;
+        }
+        for (auto &f : alphaFormats) {
+            if (codecInfo.startsWith(f)) {
+                return true;
+            }
         }
     }
     return false;
diff --git a/src/bin/projectclip.h b/src/bin/projectclip.h
index 393700091b..783ec1cff6 100644
--- a/src/bin/projectclip.h
+++ b/src/bin/projectclip.h
@@ -323,7 +323,7 @@ public:
     const QString getControlUuid() const;
     virtual size_t sequenceFrameDuration(const QUuid &);
     /** @brief returns true if an avformat producer has an alpha channel */
-    virtual bool hasAlpha();
+    virtual bool hasAlpha() const;
     /** @brief Get a list of masks */
     QVector<MaskInfo> masks() const;
     /** @brief Get a list of masks with only {name, url} */
diff --git a/src/monitor/monitor.cpp b/src/monitor/monitor.cpp
index 577be2a914..e80aabef10 100644
--- a/src/monitor/monitor.cpp
+++ b/src/monitor/monitor.cpp
@@ -847,7 +847,7 @@ void Monitor::buildBackgroundedProducer(int pos)
     if (!m_openMutex.tryLock()) {
         return;
     }
-    if (m_controller->clipType() == ClipType::Audio) {
+    if (!m_controller->hasAlpha()) {
         // No compositing required
         m_glMonitor->setProducer(producer, isActive(), pos);
     } else {