sub: fix text subtitle aspect ratio with vo_xv and vo_lavc, refactor

This fixes that vo_xv didn't display text subtitles correctly when
using anamorphic video. It didn't pass the aspect information to the
subtitle renderer. Also, try to render OSD correctly with respect to
aspect ratio settings: on vo_xv, the OSD is rendered into the video,
and needs to be "stretched" too when playing anamorphic video. When
the -monitorpixelaspect option is used, even with VOs such as vo_opengl
the OSD has to be rendered with that aspect ratio.

As preparation for future commits, replace the weird vsfilter_scale
value with a somewhat more sensible video_par member.

Also, struct mp_eosd_res is a better place for the aspect ratio
parameters, as OSD needs this too.

Use osd_draw_on_image() directly in vo_lavc, which fixes aspect ratio
issues as well.

1 files changed, 2 insertions, 0 deletions

diff --git a/sub/sub.h b/sub/sub.h
index 4f3ca905b6..3d40186b60 100644
--- a/sub/sub.h
+++ b/sub/sub.h
@@ -82,6 +82,8 @@ struct sub_bitmaps {
 struct mp_eosd_res {
     int w, h; // screen dimensions, including black borders
     int mt, mb, ml, mr; // borders (top, bottom, left, right)
+    double display_par;
+    double video_par; // PAR of the original video (for some sub decoders)
 };
 
 enum mp_osdtype {