codec/avcodec/vaapi*: Smooth subtitle subpicture display.

The subtitle subpictures are regenerated for each call to vd->Prepare.
This is not very efficient and results in flickering display of subtitles.
Implement a VASubpicture's cache to solve the flickering.

modules/codec/avcodec/vaapi.c

@@ -216,6 +216,7 @@ static int CreateSurfaces( vlc_va_vaapi_t *p_va, void **pp_hw_ctx, vlc_fourcc_t
         p_surface->i_id = pi_surface_id[i];
         p_surface->i_refcount = 0;
         p_surface->i_order = 0;
+        p_surface->i_cache = VA_INVALID_ID;
     }
 
     /* Create a context */
@@ -429,8 +430,6 @@ static int DisplayPicture( vlc_va_t *p_external, picture_t *p_picture, AVFrame *
     if( !p_picture->p_sys->surface )
         abort();
 
-    assert(p_picture->p_sys->surface->subpicture == NULL);
-
     return VLC_SUCCESS;
 }
 
@@ -462,13 +461,6 @@ static int Get( vlc_va_t *p_external, AVFrame *p_ff )
     p_surface->i_refcount++;
     p_surface->i_order = p_va->i_surface_order++;
 
-    if (p_surface->subpicture)
-        SubpictureDestroy( p_va->conn, &p_surface->i_id,
-                           p_surface->subpicture, p_surface->i_sub );
-
-    p_surface->subpicture = NULL;
-    p_surface->i_sub = 0;
-
     /* */
     for( int i = 0; i < 4; i++ )
     {
@@ -513,45 +505,6 @@ static void Delete( vlc_va_t *p_external )
     free( p_va );
 }
 
-/* */
-void SubpictureDestroy( vlc_va_conn_t *p_connection, VASurfaceID *i_surface_id,
-                        vlc_va_subpicture_t *subpicture, const int i_sub )
-{
-    VAStatus status;
-
-    for( int i = 0; i < i_sub; i++ )
-    {
-        if( ((*i_surface_id) != VA_INVALID_SURFACE) &&
-            (subpicture[i].i_id != VA_INVALID_ID) )
-        {
-            status = vaDeassociateSubpicture( p_connection->p_display, subpicture[i].i_id,
-                                              i_surface_id, 1) ;
-            assert( status == VA_STATUS_SUCCESS );
-        }
-
-        if( subpicture[i].i_id != VA_INVALID_ID )
-        {
-            status = vaDestroySubpicture( p_connection->p_display,
-                                          subpicture[i].i_id );
-            assert( status == VA_STATUS_SUCCESS );
-        }
-
-        if( subpicture[i].image.image_id != VA_INVALID_ID )
-        {
-            status = vaDestroyImage( p_connection->p_display,
-                                     subpicture[i].image.image_id );
-            assert( status == VA_STATUS_SUCCESS );
-        }
-
-        subpicture[i].image.image_id = VA_INVALID_ID;
-        subpicture[i].image.buf = VA_INVALID_ID;
-        subpicture[i].i_id = VA_INVALID_ID;
-    }
-
-    /* */
-    free( subpicture );
-}
-
 /* */
 vlc_va_t *vlc_va_NewVaapi( vlc_object_t *obj, int i_codec_id )
 {

modules/codec/avcodec/vaapi.h

@@ -27,12 +27,6 @@ struct vlc_va_conn_t
     int           i_ref_count; /* for internal use only */
 };
 
-typedef struct
-{
-    VASubpictureID  i_id;  /* VASubpictureIDs */
-    VAImage         image;
-} vlc_va_subpicture_t;
-
 typedef struct
 {
     VASurfaceID  i_id;
@@ -40,8 +34,7 @@ typedef struct
     unsigned int i_order;
 
     /* subpicture */
-    vlc_va_subpicture_t *subpicture;
-    unsigned int         i_sub; /* number of vlc_va_subpicures_t */
+    unsigned int i_cache;
 } vlc_va_surface_t;
 
 struct picture_sys_t
@@ -50,7 +43,4 @@ struct picture_sys_t
     vlc_va_surface_t *surface;
 };
 
-void SubpictureDestroy( vlc_va_conn_t *p_connection, VASurfaceID *i_surface_id,
-                        vlc_va_subpicture_t *subpicture, const int i_sub );
-
 #endif