2 * /brief Crop Detection filter
4 * /author Zachary Drew, Copyright 2005
6 * inspired by mplayer's cropdetect filter
8 * Note: The goemetry generated is zero-indexed and is inclusive of the end values
11 * -filter crop_detect debug=1 // Visualize crop
12 * -filter crop_detect frequency=25 // Detect the crop once a second
13 * -filter crop_detect frequency=0 // Never detect unless the producer changes
14 * -filter crop_detect thresh=100 // Changes the threshold (default = 25)
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software Foundation,
28 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
32 #define DEFAULT_THRESH 20
34 #include <framework/mlt.h>
40 #include "arrow_code.h"
42 #define ABS(a) ((a) >= 0 ? (a) : (-(a)))
44 // Image stack(able) method
45 static int filter_get_image( mlt_frame
this, uint8_t **image
, mlt_image_format
*format
, int *width
, int *height
, int writable
)
48 // Get the filter object and properties
49 mlt_filter filter
= mlt_frame_pop_service( this );
50 mlt_properties properties
= MLT_FILTER_PROPERTIES( filter
);
53 int error
= mlt_frame_get_image( this, image
, format
, width
, height
, 1 );
56 mlt_properties_debug( MLT_FRAME_PROPERTIES(this), "error after mlt_frame_get_image()", stderr
);
60 // Parameter that describes how often to check for the crop
61 int frequency
= mlt_properties_get_int( properties
, "frequency");
63 // Producers may start with blank footage, by default we will skip, oh, 5 frames unless overridden
64 int skip
= mlt_properties_get_int( properties
, "skip");
67 mlt_geometry_item bounds
= mlt_properties_get_data( properties
, "bounds", NULL
);
69 // Initialize if needed
70 if( bounds
== NULL
) {
71 bounds
= calloc( 1, sizeof( struct mlt_geometry_item_s
) );
74 mlt_properties_set_data( properties
, "bounds", bounds
, sizeof( struct mlt_geometry_item_s
), free
, NULL
);
77 // For periodic detection (with offset of 'skip')
78 if( frequency
== 0 || (int)(mlt_frame_get_position(this)+skip
) % frequency
!= 0)
81 mlt_properties_set_data( MLT_FRAME_PROPERTIES(this), "bounds", bounds
, sizeof( struct mlt_geometry_item_s
), NULL
, NULL
);
87 // There is no way to detect a crop for sure, so make up an arbitrary one
88 int thresh
= mlt_properties_get_int( properties
, "thresh" );
93 case mlt_image_yuv422
:
98 fprintf(stderr
, "image format not supported by filter_crop_detect\n");
102 int x
, y
, average_brightness
, deviation
; // Scratch variables
106 for( y
= 0; y
< *height
/2; y
++ ) {
108 average_brightness
= 0;
110 q
= *image
+ y
*ystride
;
111 for( x
= 0; x
< *width
; x
++ )
112 average_brightness
+= q
[x
*xstride
];
114 average_brightness
/= *width
;
116 for( x
= 0; x
< *width
; x
++ )
117 deviation
+= abs(average_brightness
- q
[x
*xstride
]);
119 if( deviation
*10 >= thresh
* *width
)
124 for( y
= *height
- 1; y
>= *height
/2; y
-- ) {
126 average_brightness
= 0;
128 q
= *image
+ y
*ystride
;
129 for( x
= 0; x
< *width
; x
++ )
130 average_brightness
+= q
[x
*xstride
];
132 average_brightness
/= *width
;
134 for( x
= 0; x
< *width
; x
++ )
135 deviation
+= abs(average_brightness
- q
[x
*xstride
]);
137 if( deviation
*10 >= thresh
* *width
)
142 for( x
= 0; x
< *width
/2; x
++ ) {
144 average_brightness
= 0;
146 q
= *image
+ x
*xstride
;
147 for( y
= 0; y
< *height
; y
++ )
148 average_brightness
+= q
[y
*ystride
];
150 average_brightness
/= *height
;
152 for( y
= 0; y
< *height
; y
++ )
153 deviation
+= abs(average_brightness
- q
[y
*ystride
]);
155 if( deviation
*10 >= thresh
* *width
)
160 for( x
= *width
- 1; x
>= *width
/2; x
-- ) {
162 average_brightness
= 0;
164 q
= *image
+ x
*xstride
;
165 for( y
= 0; y
< *height
; y
++ )
166 average_brightness
+= q
[y
*ystride
];
168 average_brightness
/= *height
;
170 for( y
= 0; y
< *height
; y
++ )
171 deviation
+= abs(average_brightness
- q
[y
*ystride
]);
173 if( deviation
*10 >= thresh
* *width
)
177 /* Debug: Draw arrows to show crop */
178 if( mlt_properties_get_int( properties
, "debug") == 1 )
180 init_arrows( format
, *width
, *height
);
182 draw_arrow(*image
, bounds
->x
, *height
/2, bounds
->x
+50, *height
/2, 100);
183 draw_arrow(*image
, *width
/2, bounds
->y
, *width
/2, bounds
->y
+50, 100);
184 draw_arrow(*image
, bounds
->w
, *height
/2, bounds
->w
-50, *height
/2, 100);
185 draw_arrow(*image
, *width
/2, bounds
->h
, *width
/2, bounds
->h
-50, 100);
186 draw_arrow(*image
, bounds
->x
, bounds
->y
, bounds
->x
+40, bounds
->y
+30, 100);
187 draw_arrow(*image
, bounds
->x
, bounds
->h
, bounds
->x
+40, bounds
->h
-30, 100);
188 draw_arrow(*image
, bounds
->w
, bounds
->y
, bounds
->w
-40, bounds
->y
+30, 100);
189 draw_arrow(*image
, bounds
->w
, bounds
->h
, bounds
->w
-40, bounds
->h
-30, 100);
192 // Convert to width and correct indexing
193 bounds
->w
-= bounds
->x
- 1;
194 bounds
->h
-= bounds
->y
- 1;
196 if( mlt_properties_get_int( properties
, "debug") == 1 )
197 fprintf(stderr
, "Top:%f Left:%f Width:%f Height:%f\n", bounds
->y
, bounds
->x
, bounds
->w
, bounds
->h
);
199 /* inject into frame */
200 mlt_properties_set_data( MLT_FRAME_PROPERTIES(this), "bounds", bounds
, sizeof( struct mlt_geometry_item_s
), NULL
, NULL
);
207 /** Filter processing.
210 static mlt_frame
filter_process( mlt_filter
this, mlt_frame frame
)
213 // Put the filter object somewhere we can find it
214 mlt_frame_push_service( frame
, this);
216 // Push the frame filter
217 mlt_frame_push_get_image( frame
, filter_get_image
);
222 /** Constructor for the filter.
224 mlt_filter
filter_crop_detect_init( char *arg
)
226 mlt_filter
this = mlt_filter_new( );
229 this->process
= filter_process
;
232 mlt_properties_set_int( MLT_FILTER_PROPERTIES(this), "frequency", 1);
233 mlt_properties_set_int( MLT_FILTER_PROPERTIES(this), "thresh", 5);
234 mlt_properties_set_int( MLT_FILTER_PROPERTIES(this), "clip", 5);
235 mlt_properties_set_int( MLT_FILTER_PROPERTIES(this), "former_producer_id", -1);
242 /** This source code will self destruct in 5...4...3...