I'm using Plasmatube on a Pixel 3A running postmarketOS with Plasma Mobile on a 6.8 kernel. It is however currently unable to play any video. A separate window opens up showing the first frame of a video but it's frozen (no playback controls). In the console the following is logged: Failed to open VDPAU backend Error loading shared library libvdpau_nvidia.so: No such file or directory [ffmpeg] AVHWDeviceContext: VDPAU device creation on X11 display :0 failed. Failed to open VDPAU backend Error loading shared library libvdpau_nvidia.so: No such file or directory [ffmpeg] AVHWDeviceContext: VDPAU device creation on X11 display :0 failed. This device uses an Adreno GPU with Mesa's Freedreno, so I'm unsure why it's trying to get a NVIDIA library in the first place.
Can confirm on Fairphone 4 phone (Qualcomm SM7225), also postmarketOS.
I was digging a bit and from https://invent.kde.org/multimedia/plasmatube/-/blob/v24.05.2/src/utils/mpvobject.cpp?ref_type=tags#L18 I was trying "mpv --hwdec=auto-safe bigbucksbunny.mov" and that prints similar messages but the video still plays, so these vdpau messages can probably be ignored. Failed to open VDPAU backend Error loading shared library libvdpau_nvidia.so: No such file or directory [ffmpeg] AVHWDeviceContext: VDPAU device creation on X11 display :0 failed. (minus any typos, I copied these messages manually)
It seems this is not actually the cause of the video not playing. If you disable hardware acceleration by commenting out line 18 in src/utils/mpvobject.cpp the error disappears, but still no video plays. A log with that line commented out and failing to play video: org.kde.plasmatube: Loading source "{24ee1339-b49b-4f42-81f6-c8dd0be1d68b}" org.kde.plasmatube: Loading source "{bb131e8c-ead5-42ab-9222-3ba6691e6f2a}" kf.purpose.externalprocess: Cannot initialize model for plugin type "ShareUrl" with data QJsonObject(): missing key "urls" qrc:/qt/qml/org/kde/kirigami/dialogs/Dialog.qml:401:33: QML Binding: Binding loop detected for property "value" qrc:/qt/qml/org/kde/kirigami/dialogs/Dialog.qml:344:18: QML ScrollView: Binding loop detected for property "implicitHeight" kf.purpose.externalprocess: Cannot initialize model for plugin type "ShareUrl" with data QJsonObject(): missing key "urls" kf.purpose.externalprocess: Cannot initialize model for plugin type "ShareUrl" with data QJsonObject(): missing key "urls" qrc:/qt/qml/org/kde/plasmatube/ui/TrendingPage.qml:10:1: QML TrendingPage: Created graphical object was not placed in the graphics scene. Not trying to load comments for an empty video id. [file] Cannot open file '': No such file or directory Failed to open . qrc:/qt/qml/org/kde/plasmatube/ui/components/VideoListItem.qml:57:9: QML QQuickImage: Cannot open: qrc:/qt/qml/org/kde/plasmatube/ui/components/api.youtube.fam-ribbers.com