subs, vo_vdpau: support RGBA color for PGS subtitles

Support passing bitmap subtitles to VOs in full RGBA color, and
implement this for libavcodec-decoded subtitle formats on decoding
side and vo_vdpau on display side. Currently this is enabled for PGS
(blu-ray) and DVB subtitles.

VDPAU seems to have sampling issues similar to known GL ones when
drawing a sub-rectangle from a larger texture with scaling, where
adjacent pixels outside the specified source rectangle affect the
result. As the bitmap subtitles may be scaled, add padding support to
the bitmap packer code.

In principle, this could be used for colored DVD subtitles too.
However, the libavcodec DVD decoder lacks parts of the resolution and
palette handling that are present in spudec.c.

Conflicts:
	libvo/vo_gl.c
	sub/dec_sub.h
	sub/sd_lavc.c

1 files changed, 1 insertions, 0 deletions

diff --git a/sub/sub.h b/sub/sub.h
index 9fd6c5329e..fc0047bba6 100644
--- a/sub/sub.h
+++ b/sub/sub.h
@@ -71,6 +71,7 @@ struct osd_state {
     double normal_scale;
     double vsfilter_scale;
     bool unscaled;
+    bool support_rgba;
 
     struct ass_renderer *osd_render;
     struct ass_library *osd_ass_library;