Gaussian blur optimisation. It now runs without skipping images with default...

Gaussian blur optimisation. It now runs without skipping images with default sigma (2.0) using my small sample video (352x240). This still needs to be optimised a lot.

modules/video_filter/gaussianblur.c

@@ -74,19 +74,19 @@ struct filter_sys_t
     double f_sigma;
     int *pi_distribution;
     int i_dim;
+    int *pi_buffer;
 };
 
 static void gaussianblur_InitDistribution( filter_sys_t *p_sys )
 {
     double f_sigma = p_sys->f_sigma;
     int i_dim = (int)(3.*f_sigma);
-    int *pi_distribution = (int*)malloc( (2*i_dim+1) * (2*i_dim+1) * sizeof( int ) );
-    int x, y;
+    int *pi_distribution = (int*)malloc( (2*i_dim+1) * sizeof( int ) );
+    int x;
     for( x = -i_dim; x <= i_dim; x++ )
-        for( y = -i_dim; y <= i_dim; y++ )
-            pi_distribution[(i_dim+y)*(2*i_dim+1)+(i_dim+x)] =
-                (int)( exp(-(x*x+y*y)/(2.*f_sigma*f_sigma))
-                       / (2.*M_PI*f_sigma*f_sigma) * (double)(1<<16) );
+        pi_distribution[i_dim+x] =
+            (int)( sqrt( exp(-(x*x)/(f_sigma*f_sigma))
+                   / (2.*M_PI*f_sigma*f_sigma) )* (double)(1<<16) );
     p_sys->i_dim = i_dim;
     p_sys->pi_distribution = pi_distribution;
 }
@@ -117,6 +117,7 @@ static int Create( vlc_object_t *p_this )
     gaussianblur_InitDistribution( p_filter->p_sys );
     msg_Dbg( p_filter, "gaussian distribution is %d pixels wide",
              p_filter->p_sys->i_dim*2+1 );
+    p_filter->p_sys->pi_buffer = NULL;
 
     return VLC_SUCCESS;
 }
@@ -133,6 +134,8 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
     picture_t *p_outpic;
     filter_sys_t *p_sys = p_filter->p_sys;
     int i_plane;
+    int *pi_buffer;
+    const int *pi_distribution = p_sys->pi_distribution;
 
     if( !p_pic ) return NULL;
 
@@ -145,6 +148,12 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
         return NULL;
     }
 
+    p_sys->pi_buffer = (int*)realloc( p_sys->pi_buffer,
+                                      p_pic->p[Y_PLANE].i_visible_lines
+                                      * p_pic->p[Y_PLANE].i_pitch
+                                      * sizeof( int ) );
+    pi_buffer = p_sys->pi_buffer;
+
     for( i_plane = 0 ; i_plane < p_pic->i_planes ; i_plane++ )
     {
 
@@ -156,36 +165,46 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
         const int i_pitch = p_pic->p[i_plane].i_pitch;
 
         const int i_dim = p_sys->i_dim;
-        const int i_dim2 = 2*i_dim+1;
-        const int *pi_distribution = p_sys->pi_distribution;
 
         int i_line, i_col;
         const int factor = i_plane ? 1 : 0;
 
         for( i_line = 0 ; i_line < i_visible_lines ; i_line++ )
         {
-            uint8_t *p_o = &p_out[i_line*i_pitch];
             for( i_col = 0; i_col < i_visible_pitch ; i_col++ )
             {
                 int value = 0;
                 int scale = 0;
-                int x, y;
+                int x;
+                const int c = i_line*i_pitch+i_col;
+                for( x = __MAX( -i_dim, -i_col );
+                     x <= __MIN( i_dim, i_visible_pitch - i_col + 1 );
+                     x++ )
+                {
+                    const int weight = pi_distribution[x+i_dim];
+                    scale += weight;
+                    value += weight * p_in[c+(x>>factor)];
+                }
+                pi_buffer[c] = value/scale;
+            }
+        }
+        for( i_line = 0 ; i_line < i_visible_lines ; i_line++ )
+        {
+            for( i_col = 0; i_col < i_visible_pitch ; i_col++ )
+            {
+                int value = 0;
+                int scale = 0;
+                int y;
+                const int c = i_line*i_pitch+i_col;
                 for( y = __MAX( -i_dim, -i_line );
                      y <= __MIN( i_dim, i_visible_lines - i_line - 1 );
                      y++ )
                 {
-                    const int *pi_d = &pi_distribution[(y+i_dim)*i_dim2+i_dim];
-                    const uint8_t *p_i = &p_in[(i_line+(y>>factor))*i_pitch+(i_col)];
-                    for( x = __MAX( -i_dim, -i_col );
-                         x <= __MIN( i_dim, i_visible_pitch - i_col + 1 );
-                         x++ )
-                    {
-                         const int weight = pi_d[x];
-                         value += weight * p_i[x>>factor];
-                         scale += weight;
-                    }
+                    const int weight = pi_distribution[y+i_dim];
+                    scale += weight;
+                    value += weight * pi_buffer[c+(y>>factor)*i_pitch];
                 }
-                p_o[i_col] = value / scale;
+                p_out[c] = value/scale;
             }
         }
     }