Fix parsing of Display Definition Segment in DVB subtitles and use the

associated information to properly render standard definition subtitles
transmitted with an HD stream.

At some point I'll revisit the libavcodec elements and submit upstream
again. Closes #8061


git-svn-id: http://svn.mythtv.org/svn/trunk@26090 7dbf422c-18fa-0310-86e9-fd20926502f2

mythtv/external/FFmpeg/libavcodec/avcodec.h

@@ -2935,6 +2935,10 @@ typedef struct AVSubtitleRect {
     int w;         ///< width            of pict, undefined when pict is not set
     int h;         ///< height           of pict, undefined when pict is not set
     int nb_colors; ///< number of colors in pict, undefined when pict is not set
+    int display_x; ///< top left corner of region into which pict is displayed
+    int display_y; ///< top left corner of region into which pict is displayed
+    int display_w; ///< width           of region into which pict is displayed
+    int display_h; ///< height          of region into which pict is displayed
 
     /**
      * data+linesize for the bitmap of this subtitle.

mythtv/external/FFmpeg/libavcodec/dvbsubdec.c

@@ -1344,18 +1344,12 @@ static int dvbsub_display_end_segment(AVCodecContext *avctx, const uint8_t *buf,
     DVBSubCLUT *clut;
     uint32_t *clut_table;
     int i;
-    int offset_x=0, offset_y=0;
 
     sub->rects = NULL;
     sub->start_display_time = 0;
     sub->end_display_time = ctx->time_out * 1000;
     sub->format = 0;
 
-    if (display_def) {
-        offset_x = display_def->x;
-        offset_y = display_def->y;
-    }
-
     sub->num_rects = ctx->display_list_size;
 
     if (sub->num_rects > 0){
@@ -1373,10 +1367,20 @@ static int dvbsub_display_end_segment(AVCodecContext *avctx, const uint8_t *buf,
         if (!region)
             continue;
 
-        rect->x = display->x_pos + offset_x;
-        rect->y = display->y_pos + offset_y;
+        rect->x = display->x_pos;
+        rect->y = display->y_pos;
         rect->w = region->width;
         rect->h = region->height;
+        if (display_def) {
+            rect->display_x = display_def->x;
+            rect->display_y = display_def->y;
+            rect->display_w = display_def->width;
+            rect->display_h = display_def->height;
+        }
+        else {
+            rect->display_w = 720;
+            rect->display_h = 576;
+        }
         rect->nb_colors = 16;
         rect->type      = SUBTITLE_BITMAP;
         rect->pict.linesize[0] = region->width;

mythtv/libs/libmythtv/subtitlescreen.cpp

@@ -204,8 +204,10 @@ void SubtitleScreen::DisplayAVSubtitles(void)
                 // AVSubtitleRect's image data's not guaranteed to be 4 byte
                 // aligned.
 
-                QRect qrect(rect->x, rect->y, rect->w, rect->h);
-                QRect scaled = videoOut->GetImageRect(qrect);
+                QSize img_size(rect->w, rect->h);
+                QRect img_rect(rect->x, rect->y, rect->w, rect->h);
+                QRect display(rect->display_x, rect->display_y,
+                              rect->display_w, rect->display_h);
 
                 // XSUB images are based on the original video size before
                 // they were converted to DivX. We need to guess the original
@@ -216,13 +218,11 @@ void SubtitleScreen::DisplayAVSubtitles(void)
                                  (currentFrame->height <= 720)  ? 720 : 1080;
                     int width  = (currentFrame->width  <= 720)  ? 720 :
                                  (currentFrame->width  <= 1280) ? 1280 : 1920;
-                    QMatrix m;
-                    m.scale((float)currentFrame->width / width,
-                            (float)currentFrame->height / height);
-                    scaled = m.mapRect(scaled);
+                    display = QRect(0, 0, width, height);
                 }
 
-                QImage qImage(rect->w, rect->h, QImage::Format_ARGB32);
+                QRect scaled = videoOut->GetImageRect(img_rect, &display);
+                QImage qImage(img_size, QImage::Format_ARGB32);
                 for (int y = 0; y < rect->h; ++y)
                 {
                     for (int x = 0; x < rect->w; ++x)
@@ -233,7 +233,7 @@ void SubtitleScreen::DisplayAVSubtitles(void)
                     }
                 }
 
-                if (scaled.size() != qrect.size())
+                if (scaled.size() != img_size)
                 {
                     qImage = qImage.scaled(scaled.width(), scaled.height(),
                              Qt::IgnoreAspectRatio, Qt::SmoothTransformation);

mythtv/libs/libmythtv/videooutbase.cpp

@@ -1436,9 +1436,8 @@ void VideoOutput::CopyFrame(VideoFrame *to, const VideoFrame *from)
 */
 }
 
-QRect VideoOutput::GetImageRect(const QRect &rect)
+QRect VideoOutput::GetImageRect(const QRect &rect, QRect *display)
 {
-    QRect result = rect;
     float hscale, vscale, tmp;
     tmp = 0.0;
     QRect visible_osd  = GetVisibleOSDBounds(tmp, tmp, tmp);
@@ -1450,6 +1449,17 @@ QRect VideoOutput::GetImageRect(const QRect &rect)
     float pixel_aspect = (float)video_size.width() /
                          (float)video_size.height();
 
+    QRect rect1 = rect;
+    if (display && display->isValid())
+    {
+        QMatrix m0;
+        m0.scale((float)image_width  / (float)display->width(),
+                 (float)image_height / (float)display->height());
+        rect1 = m0.mapRect(rect1);
+        rect1.translate(display->left(), display->top());
+    }
+    QRect result = rect1;
+
     if (hasFullScreenOSD())
     {
         QRect dvr_rec = window.GetDisplayVideoRect();
@@ -1482,8 +1492,8 @@ QRect VideoOutput::GetImageRect(const QRect &rect)
     hscale = pixel_aspect / image_aspect;
     if (hscale < 0.99f || hscale > 1.01f)
     {
-        result.setLeft((int)(((float)rect.left() * hscale) + 0.5f));
-        result.setWidth((int)(((float)rect.width() * hscale) + 0.5f));
+        result.setLeft((int)(((float)rect1.left() * hscale) + 0.5f));
+        result.setWidth((int)(((float)rect1.width() * hscale) + 0.5f));
     }
 
     result.translate(-visible_osd.left(), -visible_osd.top());

mythtv/libs/libmythtv/videooutbase.h

@@ -247,7 +247,7 @@ class VideoOutput
 
     QString GetFilters(void) const;
     /// \brief translates caption/dvd button rectangle into 'screen' space
-    QRect   GetImageRect(const QRect &rect);
+    QRect   GetImageRect(const QRect &rect, QRect *display = NULL);
     QRect   GetSafeRect(void);
 
   protected: