]> git.sesse.net Git - vlc/blobdiff - modules/video_filter/motiondetect.c
Use filter helpers.
[vlc] / modules / video_filter / motiondetect.c
index 7e9d8a75efeee89a1973dae58e8b1abd74c22b9e..d4783e20e419742947adda57a5501ff66018d459 100644 (file)
@@ -1,7 +1,7 @@
 /*****************************************************************************
  * motiondetec.c : Second version of a motion detection plugin.
  *****************************************************************************
- * Copyright (C) 2000-2006 the VideoLAN team
+ * Copyright (C) 2000-2008 the VideoLAN team
  * $Id$
  *
  * Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
 # include "config.h"
 #endif
 
-#include <vlc/vlc.h>
+#include <vlc_common.h>
+#include <vlc_plugin.h>
 #include <vlc_sout.h>
 #include <vlc_vout.h>
 
 #include "vlc_filter.h"
+#include "filter_picture.h"
 
 /*****************************************************************************
  * Local prototypes
@@ -42,7 +44,12 @@ static int  Create    ( vlc_object_t * );
 static void Destroy   ( vlc_object_t * );
 
 static picture_t *Filter( filter_t *, picture_t * );
+static picture_t *FilterPacked( filter_t *, picture_t * );
 static void GaussianConvolution( uint32_t *, uint32_t *, int, int, int );
+static int FindShapes( uint32_t *, uint32_t *, int, int, int,
+                       int *, int *, int *, int *, int *);
+
+#define NUM_COLORS 5000
 
 /*****************************************************************************
  * Module descriptor
@@ -51,8 +58,8 @@ static void GaussianConvolution( uint32_t *, uint32_t *, int, int, int );
 #define FILTER_PREFIX "motiondetect-"
 
 vlc_module_begin();
-    set_description( _("Motion detect video filter") );
-    set_shortname( _( "Motion Detect" ));
+    set_description( N_("Motion detect video filter") );
+    set_shortname( N_( "Motion Detect" ));
     set_capability( "video filter2", 0 );
     set_category( CAT_VIDEO );
     set_subcategory( SUBCAT_VIDEO_VFILTER );
@@ -61,12 +68,6 @@ vlc_module_begin();
     set_callbacks( Create, Destroy );
 vlc_module_end();
 
-#if 0
-static const char *ppsz_filter_options[] = {
-    NULL
-};
-#endif
-
 struct filter_sys_t
 {
     uint8_t *p_oldpix;
@@ -84,23 +85,30 @@ static int Create( vlc_object_t *p_this )
 {
     filter_t *p_filter = (filter_t *)p_this;
 
+    switch( p_filter->fmt_in.video.i_chroma )
+    {
+        CASE_PLANAR_YUV
+            p_filter->pf_video_filter = Filter;
+            break;
+
+        CASE_PACKED_YUV_422
+            p_filter->pf_video_filter = FilterPacked;
+            break;
+
+        default:
+            msg_Err( p_filter, "Unsupported input chroma (%4s)",
+                     (char*)&(p_filter->fmt_in.video.i_chroma) );
+            return VLC_EGENERIC;
+    }
+
     /* Allocate structure */
     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
     if( p_filter->p_sys == NULL )
-    {
-        msg_Err( p_filter, "out of memory" );
         return VLC_ENOMEM;
-    }
-
-    p_filter->pf_video_filter = Filter;
 
     p_filter->p_sys->p_oldpix = NULL;
     p_filter->p_sys->p_buf = NULL;
 
-#if 0
-    config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
-                   p_filter->p_cfg );
-#endif
     vlc_mutex_init( &p_filter->p_sys->lock );
 
     return VLC_SUCCESS;
@@ -121,8 +129,9 @@ static void Destroy( vlc_object_t *p_this )
     free( p_filter->p_sys );
 }
 
+
 /*****************************************************************************
- * Render
+ * Filter YUV Planar
  *****************************************************************************/
 static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
 {
@@ -142,7 +151,6 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
     uint8_t *p_oldpix;
     uint8_t *p_oldpix_u;
     uint8_t *p_oldpix_v;
-    uint8_t *p_outpix;
     uint32_t *p_buf;
     uint32_t *p_buf2;
 
@@ -151,21 +159,6 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
 
     if( !p_inpic ) return NULL;
 
-    p_outpic = p_filter->pf_vout_buffer_new( p_filter );
-    if( !p_outpic )
-    {
-        msg_Warn( p_filter, "can't get output picture" );
-        if( p_inpic->pf_release )
-            p_inpic->pf_release( p_inpic );
-        return NULL;
-    }
-
-    p_outpix = p_outpic->p[Y_PLANE].p_pixels;
-    vlc_memcpy( p_outpic->p[U_PLANE].p_pixels, p_inpic->p[U_PLANE].p_pixels,
-        p_inpic->p[U_PLANE].i_pitch * p_inpic->p[U_PLANE].i_visible_lines );
-    vlc_memcpy( p_outpic->p[V_PLANE].p_pixels, p_inpic->p[V_PLANE].p_pixels,
-        p_inpic->p[V_PLANE].i_pitch * p_inpic->p[V_PLANE].i_visible_lines );
-
     if( !p_sys->p_oldpix || !p_sys->p_buf )
     {
         free( p_sys->p_oldpix );
@@ -175,6 +168,9 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
         p_sys->p_oldpix_v = malloc( i_src_pitch_u * i_num_lines_u );
         p_sys->p_buf = malloc( sizeof( uint32_t ) * i_src_pitch * i_num_lines );
         p_sys->p_buf2 = malloc( sizeof( uint32_t ) * i_src_pitch * i_num_lines);
+        vlc_memcpy( p_sys->p_oldpix, p_inpix, i_src_pitch * i_num_lines );
+        vlc_memcpy( p_sys->p_oldpix_u, p_inpix_u, i_src_pitch_u * i_num_lines_u );
+        vlc_memcpy( p_sys->p_oldpix_v, p_inpix_v, i_src_pitch_u * i_num_lines_u );
         return p_inpic;
     }
     p_oldpix = p_sys->p_oldpix;
@@ -183,6 +179,14 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
     p_buf = p_sys->p_buf;
     p_buf2 = p_sys->p_buf2;
 
+    p_outpic = filter_NewPicture( p_filter );
+    if( !p_outpic )
+    {
+        picture_Release( p_inpic );
+        return NULL;
+    }
+
+    vout_CopyPicture( p_filter, p_outpic, p_inpic );
     vlc_mutex_lock( &p_filter->p_sys->lock );
 
     /**
@@ -222,7 +226,6 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
             break;
     }
 
-    //format = 0;
     if( format )
     {
         for( line = 0; line < i_num_lines_u; line++ )
@@ -266,140 +269,198 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
     }
 
     /**
-     * Apply some smoothing to remove noise
+     * Get the areas where movement was detected
      */
-    GaussianConvolution( p_buf2, p_buf, i_src_pitch, i_num_lines, i_src_visible );
+    int colors[NUM_COLORS];
+    int color_x_min[NUM_COLORS];
+    int color_x_max[NUM_COLORS];
+    int color_y_min[NUM_COLORS];
+    int color_y_max[NUM_COLORS];
 
-    /**
-     * Copy luminance plane
-     */
-    for( i = 0; i < i_src_pitch * i_num_lines; i++ )
-    {
-        p_outpix[i] = p_inpix[i];
-    }
+    last = FindShapes( p_buf2, p_buf, i_src_pitch, i_src_visible, i_num_lines,
+                   colors, color_x_min, color_x_max, color_y_min, color_y_max );
 
     /**
-     * Label the shapes ans build the labels dependencies list
+     * Count final number of shapes
+     * Draw rectangles (there can be more than 1 moving shape in 1 rectangle)
      */
-    last = 1;
-    int colors[5000];
-    int color_x_min[5000];
-    int color_x_max[5000];
-    int color_y_min[5000];
-    int color_y_max[5000];
-
-    for( j = 0; j < i_src_pitch; j++ )
-    {
-        p_buf[j] = 0;
-        p_buf[(i_num_lines-1)*i_src_pitch+j] = 0;
-    }
-    for( i = 1; i < i_num_lines-1; i++ )
+    uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
+    const int i_dst_pitch = p_outpic->p[Y_PLANE].i_pitch;
+    j = 0;
+    for( i = 1; i < last; i++ )
     {
-        p_buf[i*i_src_pitch] = 0;
-        for( j = 1; j < i_src_pitch-1; j++ )
+        if( colors[i] == i && color_x_min[i] != -1 )
         {
-            if( p_buf[i*i_src_pitch+j] > 15 )
+            if( ( color_y_max[i] - color_y_min[i] ) * ( color_x_max[i] - color_x_min[i] ) < 16 )
+                continue;
+            j++;
+            int x, y;
+            y = color_y_min[i];
+            for( x = color_x_min[i]; x <= color_x_max[i]; x++ )
             {
-                if( p_buf[(i-1)*i_src_pitch+j-1] )
-                {
-                    p_buf[i*i_src_pitch+j] = p_buf[(i-1)*i_src_pitch+j-1];
-                }
-                else if( p_buf[(i-1)*i_src_pitch+j] )
-                    p_buf[i*i_src_pitch+j] = p_buf[(i-1)*i_src_pitch+j];
-                else if( p_buf[i*i_src_pitch+j-1] )
-                    p_buf[i*i_src_pitch+j] = p_buf[i*i_src_pitch+j-1];
-                else
-                {
-                    p_buf[i*i_src_pitch+j] = last;
-                    colors[last] = last;
-                    last++;
-                }
-                #define CHECK( A ) \
-                if( p_buf[A] && p_buf[A] != p_buf[i*i_src_pitch+j] ) \
-                { \
-                    if( p_buf[A] < p_buf[i*i_src_pitch+j] ) \
-                        colors[p_buf[i*i_src_pitch+j]] = p_buf[A]; \
-                    else \
-                        colors[p_buf[A]] = p_buf[i*i_src_pitch+j]; \
-                }
-                CHECK( i*i_src_pitch+j-1 );
-                CHECK( (i-1)*i_src_pitch+j-1 );
-                CHECK( (i-1)*i_src_pitch+j );
-                CHECK( (i-1)*i_src_pitch+j+1 );
+                p_outpix[y*i_dst_pitch+x] = 0xff;
             }
-            else
+            y = color_y_max[i];
+            for( x = color_x_min[i]; x <= color_x_max[i]; x++ )
+            {
+                p_outpix[y*i_dst_pitch+x] = 0xff;
+            }
+            x = color_x_min[i];
+            for( y = color_y_min[i]; y <= color_y_max[i]; y++ )
             {
-                p_buf[i*i_src_pitch+j] = 0;
+                p_outpix[y*i_dst_pitch+x] = 0xff;
+            }
+            x = color_x_max[i];
+            for( y = color_y_min[i]; y <= color_y_max[i]; y++ )
+            {
+                p_outpix[y*i_dst_pitch+x] = 0xff;
             }
         }
-        p_buf[i*i_src_pitch+j] = 0;
     }
+    msg_Dbg( p_filter, "Counted %d moving shapes.", j);
 
     /**
-     * Initialise empty rectangle list
+     * We're done. Lets keep a copy of the picture
      */
-    for( i = 1; i < last; i++ )
+    vlc_memcpy( p_oldpix, p_inpix, i_src_pitch * i_num_lines );
+    vlc_memcpy( p_oldpix_u, p_inpix_u, i_src_pitch_u * i_num_lines_u );
+    vlc_memcpy( p_oldpix_v, p_inpix_v, i_src_pitch_u * i_num_lines_u );
+
+    vlc_mutex_unlock( &p_filter->p_sys->lock );
+
+    return CopyInfoAndRelease( p_outpic, p_inpic );
+}
+
+/*****************************************************************************
+ * Filter YUV Packed
+ *****************************************************************************/
+static picture_t *FilterPacked( filter_t *p_filter, picture_t *p_inpic )
+{
+    picture_t *p_outpic;
+    filter_sys_t *p_sys = p_filter->p_sys;
+
+    int i_y_offset, i_u_offset, i_v_offset;
+
+    const uint8_t *p_inpix;
+    const uint8_t *p_inpix_u;
+    const uint8_t *p_inpix_v;
+
+    int i_src_pitch;
+    int i_src_visible;
+    int i_num_lines;
+
+    uint8_t *p_oldpix;
+    uint8_t *p_oldpix_u;
+    uint8_t *p_oldpix_v;
+    uint8_t *p_outpix;
+
+    uint32_t *p_buf;
+    uint32_t *p_buf2;
+
+    int i,j;
+    int last;
+
+    if( GetPackedYuvOffsets( p_inpic->format.i_chroma, &i_y_offset,
+                             &i_u_offset, &i_v_offset ) != VLC_SUCCESS )
     {
-        color_x_min[i] = -1;
-        color_x_max[i] = -1;
-        color_y_min[i] = -1;
-        color_y_max[i] = -1;
+        msg_Warn( p_filter, "Unsupported input chroma (%4s)",
+                  (char*)&(p_inpic->format.i_chroma) );
+        picture_Release( p_inpic );
+        return NULL;
+    }
+
+    p_inpix = p_inpic->p->p_pixels+i_y_offset;
+    p_inpix_u = p_inpic->p->p_pixels+i_u_offset;
+    p_inpix_v = p_inpic->p->p_pixels+i_v_offset;
+
+    i_src_pitch = p_inpic->p->i_pitch;
+    i_src_visible = p_inpic->p->i_visible_pitch;
+    i_num_lines = p_inpic->p->i_visible_lines;
+
+    if( !p_sys->p_oldpix || !p_sys->p_buf )
+    {
+        free( p_sys->p_oldpix );
+        free( p_sys->p_buf );
+        p_sys->p_oldpix = malloc( i_src_pitch * i_num_lines );
+        p_sys->p_buf = malloc( sizeof( uint32_t ) * i_src_pitch * i_num_lines / 2 );
+        p_sys->p_buf2 = malloc( sizeof( uint32_t ) * i_src_pitch * i_num_lines / 2 );
+        vlc_memcpy( p_sys->p_oldpix, p_inpic->p->p_pixels,
+                    i_src_pitch * i_num_lines );
+        return p_inpic;
+    }
+
+    p_outpic = filter_NewPicture( p_filter );
+    if( !p_outpic )
+    {
+        picture_Release( p_inpic );
+        return NULL;
     }
 
+    p_outpix = p_outpic->p->p_pixels+i_y_offset;
+    vlc_memcpy( p_outpic->p->p_pixels, p_inpic->p->p_pixels,
+                p_inpic->p->i_pitch * p_inpic->p->i_visible_lines );
+
+    p_oldpix = p_sys->p_oldpix+i_y_offset;
+    p_oldpix_u = p_sys->p_oldpix+i_u_offset;
+    p_oldpix_v = p_sys->p_oldpix+i_v_offset;
+    p_buf = p_sys->p_buf;
+    p_buf2 = p_sys->p_buf2;
+
+    vlc_mutex_lock( &p_filter->p_sys->lock );
+
     /**
-     * Compute rectangle coordinates
+     * Substract Y planes
      */
-    for( i = 0; i < i_src_pitch * i_num_lines; i++ )
+    for( i = 0; i < i_src_pitch * i_num_lines; i+=2 )
     {
-        if( p_buf[i] )
+        if( p_inpix[i] > p_oldpix[i] )
         {
-            while( colors[p_buf[i]] != p_buf[i] )
-                p_buf[i] = colors[p_buf[i]];
-            if( color_x_min[p_buf[i]] == -1 )
-            {
-                color_x_min[p_buf[i]] =
-                color_x_max[p_buf[i]] = i % i_src_pitch;
-                color_y_min[p_buf[i]] =
-                color_y_max[p_buf[i]] = i / i_src_pitch;
-            }
-            else
-            {
-                int x = i % i_src_pitch, y = i / i_src_pitch;
-                if( x < color_x_min[p_buf[i]] )
-                    color_x_min[p_buf[i]] = x;
-                if( x > color_x_max[p_buf[i]] )
-                    color_x_max[p_buf[i]] = x;
-                if( y < color_y_min[p_buf[i]] )
-                    color_y_min[p_buf[i]] = y;
-                if( y > color_y_max[p_buf[i]] )
-                    color_y_max[p_buf[i]] = y;
-            }
+            p_buf2[i>>1] = p_inpix[i] - p_oldpix[i];
+        }
+        else
+        {
+            p_buf2[i>>1] = p_oldpix[i] - p_inpix[i];
         }
     }
 
-    /**
-     * Merge overlaping rectangles
-     */
-    for( i = 1; i < last; i++ )
+#if 0
+    for( i = 0; i < i_src_pitch * i_num_lines; i+=4 )
     {
-        if( colors[i] != i ) continue;
-        if( color_x_min[i] == -1 ) continue;
-        for( j = i+1; j < last; j++ )
+        int diff;
+        if( p_inpix_u[i] > p_oldpix_u[i] )
         {
-            if( colors[j] != j ) continue;
-            if( color_x_min[j] == -1 ) continue;
-            if( __MAX( color_x_min[i], color_x_min[j] ) < __MIN( color_x_max[i], color_x_max[j] ) &&
-                __MAX( color_y_min[i], color_y_min[j] ) < __MIN( color_y_max[i], color_y_max[j] ) )
-            {
-                color_x_min[i] = __MIN( color_x_min[i], color_x_min[j] );
-                color_x_max[i] = __MAX( color_x_max[i], color_x_max[j] );
-                color_y_min[i] = __MIN( color_y_min[i], color_y_min[j] );
-                color_y_max[i] = __MAX( color_y_max[i], color_y_max[j] );
-                color_x_min[j] = -1;
-                j = 0;
-            }
+            diff = p_inpix_u[i] - p_oldpix_u[i];
         }
+        else
+        {
+            diff = p_oldpix_u[i] - p_inpix_u[i];
+        }
+        if( p_inpix_v[i] > p_oldpix_v[i] )
+        {
+            diff += p_inpix_v[i] - p_oldpix_v[i];
+        }
+        else
+        {
+            diff += p_oldpix_v[i] - p_inpix_v[i];
+        }
+
+        p_buf2[(i>>2)<<1] += diff;
+        p_buf2[((i>>2)<<1)+1] += diff;
     }
+#endif
+
+    /**
+     * Get the areas where movement was detected
+     */
+    int colors[5000];
+    int color_x_min[5000];
+    int color_x_max[5000];
+    int color_y_min[5000];
+    int color_y_max[5000];
+
+    last = FindShapes( p_buf2, p_buf, i_src_pitch/2, i_src_visible/2,
+                       i_num_lines, colors, color_x_min, color_x_max,
+                       color_y_min, color_y_max );
 
     /**
      * Count final number of shapes
@@ -412,23 +473,24 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
         {
             if( ( color_y_max[i] - color_y_min[i] ) * ( color_x_max[i] - color_x_min[i] ) < 16 ) continue;
             j++;
+            printf("Shape: (%d,%d) (%d,%d)\n", color_y_max[i], color_y_min[i], color_x_max[i], color_x_min[i] );
             int x, y;
             y = color_y_min[i];
-            for( x = color_x_min[i]; x <= color_x_max[i]; x++ )
+            for( x = color_x_min[i]*2; x <= color_x_max[i]*2; x+=2 )
             {
                 p_outpix[y*i_src_pitch+x] = 0xff;
             }
             y = color_y_max[i];
-            for( x = color_x_min[i]; x <= color_x_max[i]; x++ )
+            for( x = color_x_min[i]*2; x <= color_x_max[i]*2; x+=2 )
             {
                 p_outpix[y*i_src_pitch+x] = 0xff;
             }
-            x = color_x_min[i];
+            x = color_x_min[i]*2;
             for( y = color_y_min[i]; y <= color_y_max[i]; y++ )
             {
                 p_outpix[y*i_src_pitch+x] = 0xff;
             }
-            x = color_x_max[i];
+            x = color_x_max[i]*2;
             for( y = color_y_min[i]; y <= color_y_max[i]; y++ )
             {
                 p_outpix[y*i_src_pitch+x] = 0xff;
@@ -440,23 +502,11 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_inpic )
     /**
      * We're done. Lets keep a copy of the picture
      */
-    vlc_memcpy( p_oldpix, p_inpix, i_src_pitch * i_num_lines );
-    vlc_memcpy( p_oldpix_u, p_inpix_u, i_src_pitch_u * i_num_lines_u );
-    vlc_memcpy( p_oldpix_v, p_inpix_v, i_src_pitch_u * i_num_lines_u );
+    vlc_memcpy( p_sys->p_oldpix, p_inpic->p->p_pixels, i_src_pitch * i_num_lines );
 
     vlc_mutex_unlock( &p_filter->p_sys->lock );
 
-    /* misc stuff */
-    p_outpic->date = p_inpic->date;
-    p_outpic->b_force = p_inpic->b_force;
-    p_outpic->i_nb_fields = p_inpic->i_nb_fields;
-    p_outpic->b_progressive = p_inpic->b_progressive;
-    p_outpic->b_top_field_first = p_inpic->b_top_field_first;
-
-    if( p_inpic->pf_release )
-        p_inpic->pf_release( p_inpic );
-
-    return p_outpic;
+    return CopyInfoAndRelease( p_outpic, p_inpic );
 }
 
 
@@ -475,11 +525,6 @@ static void GaussianConvolution( uint32_t *p_inpix, uint32_t *p_smooth,
                                  int i_src_pitch, int i_num_lines,
                                  int i_src_visible )
 {
-/*    const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
-    const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
-    const int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
-    const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;*/
-
     int x,y;
     for( y = 2; y < i_num_lines - 2; y++ )
     {
@@ -520,3 +565,143 @@ static void GaussianConvolution( uint32_t *p_inpix, uint32_t *p_smooth,
         }
     }
 }
+
+/*****************************************************************************
+ *
+ *****************************************************************************/
+static int FindShapes( uint32_t *p_diff, uint32_t *p_smooth,
+                       int i_pitch, int i_visible, int i_lines,
+                       int *colors,
+                       int *color_x_min, int *color_x_max,
+                       int *color_y_min, int *color_y_max )
+{
+    int last = 1;
+    int i, j;
+
+    /**
+     * Apply some smoothing to remove noise
+     */
+    GaussianConvolution( p_diff, p_smooth, i_pitch, i_visible, i_lines );
+
+    /**
+     * Label the shapes and build the labels dependencies list
+     */
+    for( j = 0; j < i_pitch; j++ )
+    {
+        p_smooth[j] = 0;
+        p_smooth[(i_lines-1)*i_pitch+j] = 0;
+    }
+    for( i = 1; i < i_lines-1; i++ )
+    {
+        p_smooth[i*i_pitch] = 0;
+        for( j = 1; j < i_pitch-1; j++ )
+        {
+            if( p_smooth[i*i_pitch+j] > 15 )
+            {
+                if( p_smooth[(i-1)*i_pitch+j-1] )
+                {
+                    p_smooth[i*i_pitch+j] = p_smooth[(i-1)*i_pitch+j-1];
+                }
+                else if( p_smooth[(i-1)*i_pitch+j] )
+                    p_smooth[i*i_pitch+j] = p_smooth[(i-1)*i_pitch+j];
+                else if( p_smooth[i*i_pitch+j-1] )
+                    p_smooth[i*i_pitch+j] = p_smooth[i*i_pitch+j-1];
+                else
+                {
+                    if( last < 5000 )
+                    {
+                        p_smooth[i*i_pitch+j] = last;
+                        colors[last] = last;
+                        last++;
+                    }
+                }
+                #define CHECK( A ) \
+                if( p_smooth[A] && p_smooth[A] != p_smooth[i*i_pitch+j] ) \
+                { \
+                    if( p_smooth[A] < p_smooth[i*i_pitch+j] ) \
+                        colors[p_smooth[i*i_pitch+j]] = p_smooth[A]; \
+                    else \
+                        colors[p_smooth[A]] = p_smooth[i*i_pitch+j]; \
+                }
+                CHECK( i*i_pitch+j-1 );
+                CHECK( (i-1)*i_pitch+j-1 );
+                CHECK( (i-1)*i_pitch+j );
+                CHECK( (i-1)*i_pitch+j+1 );
+                #undef CHECK
+            }
+            else
+            {
+                p_smooth[i*i_pitch+j] = 0;
+            }
+        }
+        p_smooth[i*i_pitch+j] = 0;
+    }
+
+    /**
+     * Initialise empty rectangle list
+     */
+    for( i = 1; i < last; i++ )
+    {
+        color_x_min[i] = -1;
+        color_x_max[i] = -1;
+        color_y_min[i] = -1;
+        color_y_max[i] = -1;
+    }
+
+    /**
+     * Compute rectangle coordinates
+     */
+    for( i = 0; i < i_pitch * i_lines; i++ )
+    {
+        if( p_smooth[i] )
+        {
+            while( colors[p_smooth[i]] != (int)p_smooth[i] )
+                p_smooth[i] = colors[p_smooth[i]];
+            if( color_x_min[p_smooth[i]] == -1 )
+            {
+                color_x_min[p_smooth[i]] =
+                color_x_max[p_smooth[i]] = i % i_pitch;
+                color_y_min[p_smooth[i]] =
+                color_y_max[p_smooth[i]] = i / i_pitch;
+            }
+            else
+            {
+                int x = i % i_pitch, y = i / i_pitch;
+                if( x < color_x_min[p_smooth[i]] )
+                    color_x_min[p_smooth[i]] = x;
+                if( x > color_x_max[p_smooth[i]] )
+                    color_x_max[p_smooth[i]] = x;
+                if( y < color_y_min[p_smooth[i]] )
+                    color_y_min[p_smooth[i]] = y;
+                if( y > color_y_max[p_smooth[i]] )
+                    color_y_max[p_smooth[i]] = y;
+            }
+        }
+    }
+
+    /**
+     * Merge overlaping rectangles
+     */
+    for( i = 1; i < last; i++ )
+    {
+        if( colors[i] != i ) continue;
+        if( color_x_min[i] == -1 ) continue;
+        for( j = i+1; j < last; j++ )
+        {
+            if( colors[j] != j ) continue;
+            if( color_x_min[j] == -1 ) continue;
+            if( __MAX( color_x_min[i], color_x_min[j] ) < __MIN( color_x_max[i], color_x_max[j] ) &&
+                __MAX( color_y_min[i], color_y_min[j] ) < __MIN( color_y_max[i], color_y_max[j] ) )
+            {
+                color_x_min[i] = __MIN( color_x_min[i], color_x_min[j] );
+                color_x_max[i] = __MAX( color_x_max[i], color_x_max[j] );
+                color_y_min[i] = __MIN( color_y_min[i], color_y_min[j] );
+                color_y_max[i] = __MAX( color_y_max[i], color_y_max[j] );
+                color_x_min[j] = -1;
+                j = 0;
+            }
+        }
+    }
+
+    return last;
+}