Pi: Background shows through with ffmpeg & openmax

aa676f7 prevented background bleed where the decoder was openmax
but does not cover the case where the decoder is ffmpeg and the renderer is openmax,
which still bleeds through. This is a viable combination which provides better quality
than openmax decoder in some cases.

Also fixes a segfault documented by #12700 & #12709, which was introduced by the fix for #12691.

Fixes #12693

Signed-off-by: Roger Siddons <rsiddons@mythtv.org>

mythtv/libs/libmythtv/tv_play.cpp

@@ -2610,11 +2610,16 @@ void TV::HandleStateChange(PlayerContext *mctx, PlayerContext *ctx)
             QSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX));
         mainWindow->setGeometry(player_bounds);
         mainWindow->ResizePainterWindow(player_bounds.size());
-        // PGB Do not disable the GUI when using openmax decoder,
+        // PGB Do not disable the GUI when using openmax renderer,
         // to ensure that space next to letterbox pictures
         // is painted.
-        QString decName = ctx->player->GetDecoder()->GetCodecDecoderName();
-        if (decName != "openmax" && !weDisabledGUI)
+        bool isOpenMaxRender = false;
+        if (ctx && ctx->player)
+        {
+            VideoOutput *vo = ctx->player->GetVideoOutput();
+            isOpenMaxRender = vo && vo->GetName() == "openmax";
+        }
+        if (!isOpenMaxRender && !weDisabledGUI)
         {
             weDisabledGUI = true;
             GetMythMainWindow()->PushDrawDisabled();

mythtv/libs/libmythtv/videoout_omx.h

@@ -32,6 +32,7 @@ class VideoOutputOMX : public VideoOutput, private OMXComponentCtx
     virtual bool ApproveDeintFilter(const QString&) const;
     virtual bool SetDeinterlacingEnabled(bool interlaced);
     virtual bool SetupDeinterlace(bool interlaced, const QString& ovrf="");
+    virtual QString GetName(void) const { return kName; } // = "openmax"
     virtual bool IsPIPSupported(void) const { return true; }
     virtual bool IsPBPSupported(void) const { return true; }
     virtual QRect GetPIPRect(PIPLocation, MythPlayer* = NULL, bool = true) const;

mythtv/libs/libmythtv/videooutbase.h

@@ -145,6 +145,7 @@ class VideoOutput
 
     bool AllowPreviewEPG(void) const;
 
+    virtual QString GetName(void) const { return QString(); }
     virtual bool IsPIPSupported(void) const { return false; }
     virtual bool IsPBPSupported(void) const { return false; }
     virtual bool NeedExtraAudioDecode(void) const { return false; }