UI: Try to fix crashes when creating MPV

Try to force the window creation before passing the WID to MPV to fix
the possibility where the window is not already created and thus
everything crashes.

src/UI/DocumentViews/MpvContainer.cc

@@ -19,6 +19,14 @@ MpvContainer::MpvContainer(QWidget *parent)
 
     setAttribute(Qt::WA_DontCreateNativeAncestors);
     setAttribute(Qt::WA_NativeWindow);
+}
+
+void
+MpvContainer::intializeMpv()
+{
+    if (isMpvAlreadyInitialized)
+        throw std::logic_error("MPV is already initialized!");
+    isMpvAlreadyInitialized = true;
 
     quint64 wid = winId();
     mpv_set_option(mpv, "wid", MPV_FORMAT_INT64, &wid);

src/UI/DocumentViews/MpvContainer.hh

@@ -32,6 +32,7 @@ class MpvContainer final : public QWidget {
 
 private:
     bool isPlaybackPaused{ true };
+    bool isMpvAlreadyInitialized{ false };
     mpv_handle *volatile mpv{ nullptr };
     qint64 sid{ -1 };
     std::function<void(double)> mpvTimeCallback{ nullptr };
@@ -39,6 +40,7 @@ private:
 
 public:
     explicit MpvContainer(QWidget *parent);
+    void intializeMpv();
     ~MpvContainer() noexcept override;
 
     void loadFile(const QString &) noexcept;

src/UI/DocumentViews/VideoView.cc

@@ -14,6 +14,8 @@ VideoView::VideoView(QWidget *parent) noexcept
     centralLayout->addWidget(new MpvControls(mpv, this));
 
     setLayout(centralLayout);
+
+    mpv->intializeMpv();
 }
 
 void