--- /dev/null
+/*****************************************************************************
+ * seamcarving.c: "Seam Carving for Content-Aware Image Resizing"
+ * Based on paper by Shai Avidan and Ariel Shamir.
+ *****************************************************************************
+ * Copyright (C) 2007 the VideoLAN team
+ * $Id$
+ *
+ * Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+
+#include <vlc/vlc.h>
+#include <vlc_sout.h>
+#include <vlc_vout.h>
+
+#include "vlc_filter.h"
+
+#include <assert.h>
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int Create ( vlc_object_t * );
+static void Destroy ( vlc_object_t * );
+
+static picture_t *Filter( filter_t *, picture_t * );
+static int CropCallback( vlc_object_t *, char const *,
+ vlc_value_t, vlc_value_t,
+ void * );
+
+static void FilterSeamCarving( filter_t *, picture_t *, picture_t * );
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+
+#define FILTER_PREFIX "seamcarving-"
+
+vlc_module_begin();
+ set_description( _("Seam Carving video filter") );
+ set_shortname( _( "Seam Carvinf" ));
+ set_capability( "video filter2", 0 );
+ set_category( CAT_VIDEO );
+ set_subcategory( SUBCAT_VIDEO_VFILTER );
+
+ set_callbacks( Create, Destroy );
+vlc_module_end();
+
+static const char *ppsz_filter_options[] = {
+ NULL
+};
+
+struct filter_sys_t
+{
+ int *p_energy;
+ int *p_grad;
+
+ int i_crop;
+};
+
+static int Create( vlc_object_t *p_this )
+{
+ filter_t *p_filter = (filter_t *)p_this;
+
+ /* 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_energy = NULL;
+ p_filter->p_sys->p_grad = NULL;
+ p_filter->p_sys->i_crop = 0;
+
+ config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
+ p_filter->p_cfg );
+
+ var_Create( p_filter, "crop", VLC_VAR_INTEGER|VLC_VAR_ISCOMMAND );
+ var_AddCallback( p_filter, "crop", CropCallback, p_filter->p_sys );
+
+ return VLC_SUCCESS;
+}
+
+static void Destroy( vlc_object_t *p_this )
+{
+ filter_t *p_filter = (filter_t *)p_this;
+
+ free( p_filter->p_sys->p_energy );
+ free( p_filter->p_sys->p_grad );
+
+ free( p_filter->p_sys );
+}
+
+static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
+{
+ picture_t *p_outpic;
+
+ if( !p_pic ) 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_pic->pf_release )
+ p_pic->pf_release( p_pic );
+ return NULL;
+ }
+
+ FilterSeamCarving( p_filter, p_pic, p_outpic );
+
+ p_outpic->date = p_pic->date;
+ p_outpic->b_force = p_pic->b_force;
+ p_outpic->i_nb_fields = p_pic->i_nb_fields;
+ p_outpic->b_progressive = p_pic->b_progressive;
+ p_outpic->b_top_field_first = p_pic->b_top_field_first;
+
+ if( p_pic->pf_release )
+ p_pic->pf_release( p_pic );
+
+ return p_outpic;
+}
+
+static inline int min3( int a, int b, int c );
+static inline int min( int a, int b );
+static int RemoveVerticalSeam( filter_t *p_filter, picture_t *p_inpic, picture_t *p_outpic, int i_src_visible );
+
+//#define DRAW_GRADIENT
+//#define DRAW_ENERGY
+//#define DRAW_SEAM
+
+static void FilterSeamCarving( filter_t *p_filter, picture_t *p_inpic,
+ picture_t *p_outpic )
+{
+ const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
+ const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
+
+ int i_src_visible = p_inpic->p[Y_PLANE].i_visible_pitch;
+
+ if( !p_filter->p_sys->p_energy )
+ p_filter->p_sys->p_energy = (int*)malloc(i_src_pitch * i_num_lines * sizeof(int));
+ if( !p_filter->p_sys->p_grad )
+ p_filter->p_sys->p_grad = (int*)malloc(i_src_pitch * i_num_lines * sizeof(int));
+
+//#if defined( DRAW_GRADIENT ) || defined( DRAW_ENERGY ) || defined( DRAW_SEAM )
+ p_filter->p_libvlc->pf_memcpy( p_outpic->p[Y_PLANE].p_pixels,
+ p_inpic->p[Y_PLANE].p_pixels,
+ p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
+//#else
+// p_filter->p_libvlc->pf_memset( p_outpix, 0x80,
+// p_outpic->p[Y_PLANE].i_lines * p_outpic->p[Y_PLANE].i_pitch );
+//#endif
+ p_filter->p_libvlc->pf_memset( p_outpic->p[U_PLANE].p_pixels, 0x80,
+ p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
+ p_filter->p_libvlc->pf_memset( p_outpic->p[V_PLANE].p_pixels, 0x80,
+ p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
+
+#if defined( DRAW_GRADIENT ) || defined( DRAW_ENERGY ) || defined( DRAW_SEAM )
+ i_src_visible = RemoveVerticalSeam( p_filter, p_outpic, p_outpic, i_src_visible );
+#else
+ static int j = 1;
+ static int k = 1;
+ int i;
+ if( p_filter->p_sys->i_crop != 0 )
+ j = p_filter->p_sys->i_crop;
+ for( i = 0; i < j; i++ )
+ i_src_visible = RemoveVerticalSeam( p_filter, p_outpic, p_outpic, i_src_visible );
+ int y;
+ for( y = 0; y < p_outpic->p[Y_PLANE].i_lines; y++ )
+ p_filter->p_libvlc->pf_memset( p_outpic->p[Y_PLANE].p_pixels + y*p_outpic->p[Y_PLANE].i_pitch + i_src_visible, 0x00, p_outpic->p[Y_PLANE].i_pitch - i_src_visible );
+ j += k;
+ if( j == 100 ) k = -1;
+ if( j == 1 ) k = 1;
+#endif
+}
+
+static int ComputeGradient( filter_t *p_filter, picture_t *p_inpic, int i_src_visible )
+{
+ int x, y;
+ const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
+ const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
+
+ const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
+ int *p_grad = p_filter->p_sys->p_grad;
+
+ for( y = 1; y < i_num_lines - 1;
+ y++, p_grad += i_src_pitch )
+ {
+ /* Compute line y's gradient */
+#define GRADx( x ) \
+ ( \
+ abs( \
+ ( p_inpix[(y-1)*i_src_pitch+x-1] \
+ - p_inpix[(y+1)*i_src_pitch+x-1] ) \
+ + ( ( p_inpix[(y-1)*i_src_pitch+x] \
+ - p_inpix[(y+1)*i_src_pitch+x] ) <<1 ) \
+ + ( p_inpix[(y-1)*i_src_pitch+x+1] \
+ - p_inpix[(y+1)*i_src_pitch+x+1] ) \
+ ) \
+ + \
+ abs( \
+ ( p_inpix[(y-1)*i_src_pitch+x-1] \
+ - p_inpix[(y-1)*i_src_pitch+x+1] ) \
+ + ( ( p_inpix[y*i_src_pitch+x-1] \
+ - p_inpix[y*i_src_pitch+x+1] ) <<1 ) \
+ + ( p_inpix[(y+1)*i_src_pitch+x-1] \
+ - p_inpix[(y+1)*i_src_pitch+x+1] ) \
+ ) \
+ )
+ for( x = 1; x < i_src_visible - 1; x++ )
+ {
+ p_grad[x] = GRADx( x );
+#ifdef DRAW_GRADIENT
+ p_outpix[y*i_src_pitch+x] = p_grad[x]>>3;
+#endif
+ }
+ }
+ return 0;
+}
+
+static int RemoveVerticalSeam( filter_t *p_filter, picture_t *p_inpic, picture_t *p_outpic, int i_src_visible )
+{
+ int x, y;
+ const int i_src_pitch = p_inpic->p[Y_PLANE].i_pitch;
+ const int i_num_lines = p_inpic->p[Y_PLANE].i_visible_lines;
+
+ const uint8_t *p_inpix = p_inpic->p[Y_PLANE].p_pixels;
+ uint8_t *p_outpix = p_outpic->p[Y_PLANE].p_pixels;
+
+ int *p_energy = p_filter->p_sys->p_energy;
+ int *p_grad = p_filter->p_sys->p_grad;
+
+ ComputeGradient( p_filter, p_inpic, i_src_visible );
+
+ /** Compute the image's energy (using a sobel gradient as the base energy
+ ** function) */
+ /* Set the first energy line to 0 */
+ memset( p_energy, 0, i_src_pitch*sizeof(int));
+
+ int *p_energy_prev = p_energy;
+ for( y = 1; y < i_num_lines - 1;
+ y++, p_energy_prev = p_energy, p_energy += i_src_pitch,
+ p_grad += i_src_pitch )
+ {
+ /* Compute line y's minimum energy value for paths ending on
+ * each x */
+ x = 1;
+ p_energy[x] = min( p_energy_prev[x ]+p_grad[x ],
+ p_energy_prev[x+1]+p_grad[x+1] );
+ for( x = 2; x < i_src_visible - 2; x++ )
+ {
+ p_energy[x] = min3( p_energy_prev[x-1]+p_grad[x-1],
+ p_energy_prev[x ]+p_grad[x ],
+ p_energy_prev[x+1]+p_grad[x+1] );
+ }
+ p_energy[x] = min( p_energy_prev[x-1]+p_grad[x-1],
+ p_energy_prev[x ]+p_grad[x ] );
+
+#ifdef DRAW_ENERGY
+ int max = p_energy[1];
+ for( x = 1; x < i_src_visible - 1; x++ )
+ if( p_energy[x] > max ) max = p_energy[x];
+ for( x = 1; x < i_src_visible - 1; x++ )
+ p_outpix[y*i_src_pitch+x] = p_energy[x]*0xff/max;
+#endif
+ }
+
+ /* Find the minimum energy point on the last line */
+ y--;
+ p_energy -= i_src_pitch;
+ p_grad -= i_src_pitch;
+
+ int m = p_energy[1];
+ int xmin = 1;
+ for( x = 1; x < i_src_visible - 1; x++ )
+ {
+ if( p_energy[x] < m )
+ {
+ m = p_energy[x];
+ xmin = x;
+ }
+ }
+
+#ifdef DRAW_SEAM
+ p_outpix[y*i_src_pitch+xmin] = 0xff;
+ p_outpix[(y+1)*i_src_pitch+xmin] = 0xff;
+#else
+ memmove( p_outpix+y*i_src_pitch+xmin, p_outpix+y*i_src_pitch+xmin+1, i_src_pitch-(xmin+1) );
+ memmove( p_outpix+(y+1)*i_src_pitch+xmin, p_outpix+(y+1)*i_src_pitch+xmin+1, i_src_pitch-(xmin+1) );
+#endif
+
+ p_energy -= i_src_pitch;
+ for( ; y>1; y--, p_energy -= i_src_pitch, p_grad -= i_src_pitch )
+ {
+ if( m != p_energy[xmin]+p_grad[xmin] )
+ {
+ if( xmin > 1 && m == p_energy[xmin-1]+p_grad[xmin-1] )
+ {
+ xmin--;
+ }
+ else if( xmin < i_src_visible - 2 && m == p_energy[xmin+1]+p_grad[xmin+1] )
+ {
+ xmin++;
+ }
+ else
+ {
+ printf("Alarm! %d\n" ,y);
+ //assert( 0 );
+ }
+ }
+ m = p_energy[xmin];
+#ifdef DRAW_SEAM
+ p_outpix[y*i_src_pitch+xmin] = 0xff;
+#else
+ memmove( p_outpix+y*i_src_pitch+xmin, p_outpix+y*i_src_pitch+xmin+1, i_src_pitch-(xmin+1) );
+#endif
+ }
+#ifdef DRAW_SEAM
+ p_outpix[y*i_src_pitch+xmin] = 0xff;
+#else
+ memmove( p_outpix+y*i_src_pitch+xmin, p_outpix+y*i_src_pitch+xmin+1, i_src_pitch-(xmin+1) );
+#endif
+ y--;
+#ifdef DRAW_SEAM
+ p_outpix[y*i_src_pitch+xmin] = 0xff;
+#else
+ memmove( p_outpix+y*i_src_pitch+xmin, p_outpix+y*i_src_pitch+xmin+1, i_src_pitch-(xmin+1) );
+#endif
+
+#if defined( DRAW_SEAM )
+ return i_src_visible;
+#else
+ return i_src_visible-1;
+#endif
+}
+
+static inline int min3( int a, int b, int c )
+{
+ if( a < b )
+ {
+ if( a < c ) return a;
+ return c;
+ }
+ if( b < c ) return b;
+ return c;
+}
+static inline int min( int a, int b )
+{
+ return a < b ? a : b;
+}
+
+static int CropCallback( vlc_object_t *p_this, char const *psz_var,
+ vlc_value_t oldval, vlc_value_t newval,
+ void *p_data )
+{
+ filter_sys_t *p_sys = (filter_sys_t *)p_data;
+ p_sys->i_crop = newval.i_int;
+ return VLC_SUCCESS;
+}
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