codec/avcodec/vaapi.c: increase the number of surfaces.

Increase the number of surfaces requested to 30. VAAPI X11 vout
creates enough pictures to take the direct rendering code path
in vout core. Which means there are about 30 pictures in flight.

With a low number of surfaces these will be reused before they
are being displayed and this results in out of order display of
pictures. The viewer will see a stuttering image.

modules/codec/avcodec/vaapi.c

@@ -29,6 +29,7 @@
 #include <vlc_fourcc.h>
 #include <vlc_picture.h>
 #include <assert.h>
+#include <vlc_arrays.h>
 
 #ifdef HAVE_LIBAVCODEC_AVCODEC_H
 #   include <libavcodec/avcodec.h>
@@ -86,35 +87,39 @@ static int Open( vlc_va_vaapi_t *p_va, int i_codec_id )
     VAProfile i_profile;
     int i_surface_count;
 
-    /* */
+    /* NOTE: The number of surfaces requested is calculated
+       based on the amount of pictures vout core needs for
+       direct rendering. In general that is 20/30 pictures.
+
+       i_surface_count = requested_count - (codec_needs + 1)
+                         + codec_needs + 1;
+     */
     switch( i_codec_id )
     {
     case CODEC_ID_MPEG1VIDEO:
     case CODEC_ID_MPEG2VIDEO:
         i_profile = VAProfileMPEG2Main;
-        i_surface_count = 2+1;
+        i_surface_count = 17+2+1;
         break;
     case CODEC_ID_MPEG4:
         i_profile = VAProfileMPEG4AdvancedSimple;
-        i_surface_count = 2+1;
+        i_surface_count = 17+2+1;
         break;
     case CODEC_ID_WMV3:
         i_profile = VAProfileVC1Main;
-        i_surface_count = 2+1;
+        i_surface_count = 17+2+1;
         break;
     case CODEC_ID_VC1:
         i_profile = VAProfileVC1Advanced;
-        i_surface_count = 2+1;
+        i_surface_count = 17+2+1;
         break;
     case CODEC_ID_H264:
         i_profile = VAProfileH264High;
-        i_surface_count = 16+1;
+        i_surface_count = 13+16+1;
         break;
     default:
         return VLC_EGENERIC;
     }
-    /* FIXME: in case of vaapi-x11 double the number of surfaces */
-    i_surface_count *= 2;
 
     /* */
     memset( p_va, 0, sizeof(*p_va) );