[subtitles] Improved align to video condition based on ratio

3 files changed, 24 insertions, 12 deletions

diff --git a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRenderer.h b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRenderer.h
index 437f570003..0d82de9b6a 100644
--- a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRenderer.h
+++ b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRenderer.h
@@ -94,6 +94,14 @@ namespace OVERLAY {
     float m_height;
     float m_source_width{0}; // Video source width resolution used to calculate aspect ratio
     float m_source_height{0}; // Video source height resolution used to calculate aspect ratio
+
+  protected:
+    /*!
+     * \brief Given the resolution ratio determines if it is a 4/3 resolution
+     * \param resRatio The resolution ratio (the results of width / height)
+     * \return True if the ratio refer to a 4/3 resolution, otherwise false
+     */
+    bool IsSquareResolution(float resRatio) { return resRatio > 1.22f && resRatio < 1.34f; }
   };
 
   class CRenderer : public Observer
diff --git a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererDX.cpp b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererDX.cpp
index 88e75108af..8d5f74685d 100644
--- a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererDX.cpp
+++ b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererDX.cpp
@@ -25,6 +25,8 @@
 #define ASSERT(f) _ASSERTE((f))
 #endif
 
+#include <cmath>
+
 using namespace OVERLAY;
 using namespace DirectX;
 
@@ -219,14 +221,14 @@ COverlayImageDX::COverlayImageDX(CDVDOverlayImage* o, CRect& rSource)
     m_x = (0.5f * o->width + o->x) / o->source_width;
     m_y = (0.5f * o->height + o->y) / o->source_height;
 
-    int videoSourceH{static_cast<int>(rSource.Height())};
-    int videoSourceW{static_cast<int>(rSource.Width())};
+    const float subRatio{static_cast<float>(o->source_width) / o->source_height};
+    const float vidRatio{rSource.Width() / rSource.Height()};
+
+    // We always consider aligning 4/3 subtitles to the video,
+    // for example SD DVB subtitles (4/3) must be stretched on fullhd video
 
-    if ((o->source_height == videoSourceH || videoSourceH % o->source_height == 0) &&
-        (o->source_width == videoSourceW || videoSourceW % o->source_width == 0))
+    if (std::fabs(subRatio - vidRatio) < 0.001f || IsSquareResolution(subRatio))
     {
-      // We check also for multiple of source_height/source_width
-      // because for example 1080P subtitles can be used on 4K videos
       m_align = ALIGN_VIDEO;
       m_width = static_cast<float>(o->width) / o->source_width;
       m_height = static_cast<float>(o->height) / o->source_height;
diff --git a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererGL.cpp b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererGL.cpp
index a37b0fc61f..6895f74944 100644
--- a/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererGL.cpp
+++ b/xbmc/cores/VideoPlayer/VideoRenderers/OverlayRendererGL.cpp
@@ -28,6 +28,8 @@
 #include "utils/log.h"
 #include "utils/GLUtils.h"
 
+#include <cmath>
+
 #if HAS_GLES >= 2
 // GLES2.0 cant do CLAMP, but can do CLAMP_TO_EDGE.
 #define GL_CLAMP	GL_CLAMP_TO_EDGE
@@ -191,14 +193,14 @@ COverlayTextureGL::COverlayTextureGL(CDVDOverlayImage* o, CRect& rSource)
     m_x = (0.5f * o->width + o->x) / o->source_width;
     m_y = (0.5f * o->height + o->y) / o->source_height;
 
-    int videoSourceH{static_cast<int>(rSource.Height())};
-    int videoSourceW{static_cast<int>(rSource.Width())};
+    const float subRatio{static_cast<float>(o->source_width) / o->source_height};
+    const float vidRatio{rSource.Width() / rSource.Height()};
+
+    // We always consider aligning 4/3 subtitles to the video,
+    // for example SD DVB subtitles (4/3) must be stretched on fullhd video
 
-    if ((o->source_height == videoSourceH || videoSourceH % o->source_height == 0) &&
-        (o->source_width == videoSourceW || videoSourceW % o->source_width == 0))
+    if (std::fabs(subRatio - vidRatio) < 0.001f || IsSquareResolution(subRatio))
     {
-      // We check also for multiple of source_height/source_width
-      // because for example 1080P subtitles can be used on 4K videos
       m_align = ALIGN_VIDEO;
       m_width = static_cast<float>(o->width) / o->source_width;
       m_height = static_cast<float>(o->height) / o->source_height;