video_output: allow the display to scale the SPU

Don't do it for text based subpictures so they are rendered at the proper
resolution.

include/vlc_spu.h

@@ -73,7 +73,10 @@ VLC_API void spu_PutSubpicture( spu_t *, subpicture_t * );
  *
  * The returned value if non NULL must be released by subpicture_Delete().
  */
-VLC_API subpicture_t * spu_Render( spu_t *, const vlc_fourcc_t *p_chroma_list, const video_format_t *p_fmt_dst, const video_format_t *p_fmt_src, vlc_tick_t render_subtitle_date, vlc_tick_t render_osd_date, bool ignore_osd );
+VLC_API subpicture_t * spu_Render( spu_t *, const vlc_fourcc_t *p_chroma_list,
+                                   const video_format_t *p_fmt_dst, const video_format_t *p_fmt_src,
+                                   vlc_tick_t render_subtitle_date, vlc_tick_t render_osd_date,
+                                   bool ignore_osd, bool external_scale );
 
 /**
  * It registers a new SPU channel.

include/vlc_vout_display.h

@@ -112,6 +112,7 @@ typedef struct {
     bool is_slow;                           /* The picture memory has slow read/write */
     bool has_double_click;                  /* Is double-click generated */
     bool has_pictures_invalid;              /* Will VOUT_DISPLAY_EVENT_PICTURES_INVALID be used */
+    bool can_scale_spu;                     /* Handles subpictures with a non default zoom factor */
     const vlc_fourcc_t *subpicture_chromas; /* List of supported chromas for subpicture rendering. */
 } vout_display_info_t;
 

modules/stream_out/transcode/video.c

@@ -406,7 +406,7 @@ static picture_t * RenderSubpictures( sout_stream_t *p_stream, sout_stream_id_sy
 
     subpicture_t *p_subpic = spu_Render( id->p_spu, NULL, &fmt,
                                          &outfmt,
-                                         p_pic->date, p_pic->date, false );
+                                         p_pic->date, p_pic->date, false, false );
 
     /* Overlay subpicture */
     if( p_subpic )

src/video_output/video_output.c

@@ -1115,7 +1115,8 @@ static int ThreadDisplayRenderPicture(vout_thread_t *vout, bool is_forced)
                                       subpicture_chromas, &fmt_spu_rot,
                                       &vd->source,
                                       render_subtitle_date, render_osd_date,
-                                      do_snapshot);
+                                      do_snapshot,
+                                      vd->info.can_scale_spu);
     /*
      * Perform rendering
      *

src/video_output/vout_subpictures.c

@@ -1010,7 +1010,8 @@ static subpicture_t *SpuRenderSubpictures(spu_t *spu,
                                           const video_format_t *fmt_dst,
                                           const video_format_t *fmt_src,
                                           vlc_tick_t render_subtitle_date,
-                                          vlc_tick_t render_osd_date)
+                                          vlc_tick_t render_osd_date,
+                                          bool external_scale)
 {
     spu_private_t *sys = spu->p;
 
@@ -1114,14 +1115,33 @@ static subpicture_t *SpuRenderSubpictures(spu_t *spu,
             if (scale.w <= 0 || scale.h <= 0)
                 continue;
 
+            const bool do_external_scale = external_scale && region->fmt.i_chroma != VLC_CODEC_TEXT;
+            spu_scale_t virtual_scale = external_scale ? (spu_scale_t){ SCALE_UNIT, SCALE_UNIT } : scale;
+
             /* */
             SpuRenderRegion(spu, output_last_ptr, &area,
-                            subpic, region, scale,
+                            subpic, region, virtual_scale,
                             chroma_list, fmt_dst,
                             subtitle_area, subtitle_area_count,
                             subpic->b_subtitle ? render_subtitle_date : render_osd_date);
             if (*output_last_ptr)
+            {
+                if (do_external_scale)
+                {
+                    if (scale.h != SCALE_UNIT)
+                    {
+                        (*output_last_ptr)->zoom_h.num = scale.h;
+                        (*output_last_ptr)->zoom_h.den = SCALE_UNIT;
+                    }
+                    if (scale.w != SCALE_UNIT)
+                    {
+                        (*output_last_ptr)->zoom_v.num = scale.w;
+                        (*output_last_ptr)->zoom_v.den = SCALE_UNIT;
+                    }
+                }
+
                 output_last_ptr = &(*output_last_ptr)->p_next;
+            }
 
             if (subpic->b_subtitle) {
                 area = spu_area_unscaled(area, scale);
@@ -1512,7 +1532,8 @@ subpicture_t *spu_Render(spu_t *spu,
                          const video_format_t *fmt_src,
                          vlc_tick_t render_subtitle_date,
                          vlc_tick_t render_osd_date,
-                         bool ignore_osd)
+                         bool ignore_osd,
+                         bool external_scale)
 {
     spu_private_t *sys = spu->p;
 
@@ -1596,7 +1617,8 @@ subpicture_t *spu_Render(spu_t *spu,
                                                 fmt_dst,
                                                 fmt_src,
                                                 render_subtitle_date,
-                                                render_osd_date);
+                                                render_osd_date,
+                                                external_scale);
     vlc_mutex_unlock(&sys->lock);
 
     return render;