modules/video_filter/canvas.c

   1 /*****************************************************************************
   2  * canvas.c : automatically resize and padd a video to fit in canvas
   3  *****************************************************************************
   4  * Copyright (C) 2008 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Antoine Cellerier <dionoea at videolan dot org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <limits.h>
  33
  34 #include <vlc_common.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_filter.h>
  37
  38 /*****************************************************************************
  39  * Local and extern prototypes.
  40  *****************************************************************************/
  41 static int  Activate( vlc_object_t * );
  42 static void Destroy( vlc_object_t * );
  43 static picture_t *Filter( filter_t *, picture_t * );
  44 static int alloc_init( filter_t *, void * );
  45
  46 /* This module effectively implements a form of picture-in-picture.
  47  *  - The outer picture is called the canvas.
  48  *  - The innter picture is callsed the subpicture.
  49  *
  50  * NB, all of the following operatons take into account aspect ratio
  51  *
  52  * A canvas is of canvas_{width,height}.
  53  * In Pad mode:
  54  *  - The subpicture is upconverted with a inverse scalefactor of:
  55  *     (The size of subpicture's largest dimension)
  56  *     --------------------------------------------
  57  *     (The size of canvas's equivalent dimension)
  58  *
  59  *   Ie, The subpicture's largest dimension is made equal to the
  60  *   equivalent canvas dimension.
  61  *
  62  *  - The upconverted subpicture's smallest dimension is then padded
  63  *    to make the upconverted subpicture have the same dimensions of
  64  *    the canvas.
  65  *
  66  * In Crop mode:
  67  *  - The subpicture is upconverted with an inverse scalefactor of:
  68  *     (The size of subpicture's smallest dimension)
  69  *     --------------------------------------------
  70  *     (The size of canvas's equivalent dimension)
  71  *
  72  *   Ie, The subpicture's smallest dimension is made equal to the
  73  *   equivalent canvas dimension. (The subpicture will then be
  74  *   larger than the canvas)
  75  *
  76  *  - The upconverted subpicture's largest dimension is then cropped
  77  *    to make the upconverted subpicture have the same dimensions of
  78  *    the canvas.
  79  */
  80
  81 /* NB, use of `padd' in this module is a 16-17th Century spelling of `pad' */
  82
  83 #define WIDTH_TEXT N_( "Output width" )
  84 #define WIDTH_LONGTEXT N_( \
  85     "Output (canvas) image width" )
  86 #define HEIGHT_TEXT N_( "Output height" )
  87 #define HEIGHT_LONGTEXT N_( \
  88     "Output (canvas) image height" )
  89 #define ASPECT_TEXT N_( "Output picture aspect ratio" )
  90 #define ASPECT_LONGTEXT N_( \
  91     "Set the canvas' picture aspect ratio. " \
  92     "If omitted, the canvas is assumed to have the same SAR as the input." )
  93 #define PADD_TEXT N_( "Pad video" )
  94 #define PADD_LONGTEXT N_( \
  95     "If enabled, video will be padded to fit in canvas after scaling. " \
  96     "Otherwise, video will be cropped to fix in canvas after scaling." )
  97 #define CANVAS_HELP N_( "Automatically resize and pad a video" )
  98
  99 #define CFG_PREFIX "canvas-"
 100
 101 /*****************************************************************************
 102  * Module descriptor
 103  *****************************************************************************/
 104 vlc_module_begin ()
 105     set_shortname( N_("Canvas") )
 106     set_description( N_("Canvas video filter") )
 107     set_capability( "video filter2", 0 )
 108     set_help( CANVAS_HELP )
 109     set_callbacks( Activate, Destroy )
 110
 111     set_category( CAT_VIDEO )
 112     set_subcategory( SUBCAT_VIDEO_VFILTER )
 113
 114     add_integer_with_range( CFG_PREFIX "width", 0, 0, INT_MAX, NULL,
 115                             WIDTH_TEXT, WIDTH_LONGTEXT, false )
 116     add_integer_with_range( CFG_PREFIX "height", 0, 0, INT_MAX, NULL,
 117                             HEIGHT_TEXT, HEIGHT_LONGTEXT, false )
 118
 119     add_string( CFG_PREFIX "aspect", NULL,
 120                 ASPECT_TEXT, ASPECT_LONGTEXT, false )
 121
 122     add_bool( CFG_PREFIX "padd", true,
 123               PADD_TEXT, PADD_LONGTEXT, false )
 124 vlc_module_end ()
 125
 126 static const char *const ppsz_filter_options[] = {
 127     "width", "height", "aspect", "padd", NULL
 128 };
 129
 130 struct filter_sys_t
 131 {
 132     filter_chain_t *p_chain;
 133 };
 134
 135 /*****************************************************************************
 136  *
 137  *****************************************************************************/
 138 static int Activate( vlc_object_t *p_this )
 139 {
 140     filter_t *p_filter = (filter_t *)p_this;
 141     unsigned i_canvas_width; /* width of output canvas */
 142     unsigned i_canvas_height; /* height of output canvas */
 143     unsigned i_canvas_aspect; /* canvas PictureAspectRatio */
 144     es_format_t fmt; /* target format after up/down conversion */
 145     char psz_croppadd[100];
 146     int i_padd,i_offset;
 147     char *psz_aspect, *psz_parser;
 148     bool b_padd;
 149     unsigned i_fmt_in_aspect;
 150
 151     if( !p_filter->b_allow_fmt_out_change )
 152     {
 153         msg_Err( p_filter, "Picture format change isn't allowed" );
 154         return VLC_EGENERIC;
 155     }
 156
 157     if( p_filter->fmt_in.video.i_chroma != p_filter->fmt_out.video.i_chroma )
 158     {
 159         msg_Err( p_filter, "Input and output chromas don't match" );
 160         return VLC_EGENERIC;
 161     }
 162
 163     config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
 164                        p_filter->p_cfg );
 165
 166     i_canvas_width = var_CreateGetInteger( p_filter, CFG_PREFIX "width" );
 167     i_canvas_height = var_CreateGetInteger( p_filter, CFG_PREFIX "height" );
 168
 169     if( i_canvas_width == 0 || i_canvas_height == 0 )
 170     {
 171         msg_Err( p_filter, "Width and height options must be set" );
 172         return VLC_EGENERIC;
 173     }
 174
 175     if( i_canvas_width & 1 || i_canvas_height & 1 )
 176     {
 177         /* If this restriction were ever relaxed, it is very important to
 178          * get the field polatiry correct */
 179         msg_Err( p_filter, "Width and height options must be even integers" );
 180         return VLC_EGENERIC;
 181     }
 182
 183     i_fmt_in_aspect = (int64_t)p_filter->fmt_in.video.i_sar_num *
 184                       p_filter->fmt_in.video.i_width *
 185                       VOUT_ASPECT_FACTOR /
 186                       p_filter->fmt_in.video.i_sar_den /
 187                       p_filter->fmt_in.video.i_height;
 188     psz_aspect = var_CreateGetNonEmptyString( p_filter, CFG_PREFIX "aspect" );
 189     if( psz_aspect )
 190     {
 191         psz_parser = strchr( psz_aspect, ':' );
 192         int numerator = atoi( psz_aspect );
 193         int denominator = psz_parser ? atoi( psz_parser+1 ) : 0;
 194         denominator = denominator == 0 ? 1 : denominator;
 195         i_canvas_aspect = numerator * VOUT_ASPECT_FACTOR / denominator;
 196         free( psz_aspect );
 197
 198         if( numerator <= 0 || denominator < 0 )
 199         {
 200             msg_Err( p_filter, "Aspect ratio must be strictly positive" );
 201             return VLC_EGENERIC;
 202         }
 203     }
 204     else
 205     {
 206         /* if there is no user supplied aspect ratio, assume the canvas
 207          * has the same sample aspect ratio as the subpicture */
 208         /* aspect = subpic_sar * canvas_width / canvas_height
 209          *  where subpic_sar = subpic_ph * subpic_par / subpic_pw */
 210         i_canvas_aspect = (uint64_t) p_filter->fmt_in.video.i_height
 211                         * i_fmt_in_aspect
 212                         * i_canvas_width
 213                         / (i_canvas_height * p_filter->fmt_in.video.i_width);
 214     }
 215
 216     b_padd = var_CreateGetBool( p_filter, CFG_PREFIX "padd" );
 217
 218     filter_sys_t *p_sys = (filter_sys_t *)malloc( sizeof( filter_sys_t ) );
 219     if( !p_sys )
 220         return VLC_ENOMEM;
 221     p_filter->p_sys = p_sys;
 222
 223     p_sys->p_chain = filter_chain_New( p_filter, "video filter2", true,
 224                                        alloc_init, NULL, p_filter );
 225     if( !p_sys->p_chain )
 226     {
 227         msg_Err( p_filter, "Could not allocate filter chain" );
 228         free( p_sys );
 229         return VLC_EGENERIC;
 230     }
 231
 232     es_format_Copy( &fmt, &p_filter->fmt_in );
 233
 234     /* one dimension will end up with one of the following: */
 235     fmt.video.i_width = i_canvas_width;
 236     fmt.video.i_height = i_canvas_height;
 237
 238     if( b_padd )
 239     {
 240         /* Padd */
 241         if( i_canvas_aspect > i_fmt_in_aspect )
 242         {
 243             /* The canvas has a wider aspect than the subpicture:
 244              *  ie, pillarbox the [scaled] subpicture */
 245             /* The following is derived form:
 246              * width = upconverted_subpic_height * subpic_par / canvas_sar
 247              *  where canvas_sar = canvas_width / (canvas_height * canvas_par)
 248              * then simplify */
 249             fmt.video.i_width = i_canvas_width
 250                               * i_fmt_in_aspect
 251                               / i_canvas_aspect;
 252             if( fmt.video.i_width & 1 ) fmt.video.i_width -= 1;
 253
 254             i_padd = (i_canvas_width - fmt.video.i_width) / 2;
 255             i_offset = (i_padd & 1);
 256             snprintf( psz_croppadd, 100, "croppadd{paddleft=%d,paddright=%d}",
 257                       i_padd - i_offset, i_padd + i_offset );
 258         }
 259         else
 260         {
 261             /* The canvas has a taller aspect than the subpicture:
 262              *  ie, letterbox the [scaled] subpicture */
 263             fmt.video.i_height = i_canvas_height
 264                                * i_canvas_aspect
 265                                / i_fmt_in_aspect;
 266             if( fmt.video.i_height & 1 ) fmt.video.i_height -= 1;
 267
 268             i_padd = (i_canvas_height - fmt.video.i_height ) / 2;
 269             i_offset = (i_padd & 1);
 270             snprintf( psz_croppadd, 100, "croppadd{paddtop=%d,paddbottom=%d}",
 271                       i_padd - i_offset, i_padd + i_offset );
 272         }
 273     }
 274     else
 275     {
 276         /* Crop */
 277         if( i_canvas_aspect < i_fmt_in_aspect )
 278         {
 279             /* The canvas has a narrower aspect than the subpicture:
 280              *  ie, crop the [scaled] subpicture horizontally */
 281             fmt.video.i_width = i_canvas_width
 282                               * i_fmt_in_aspect
 283                               / i_canvas_aspect;
 284             if( fmt.video.i_width & 1 ) fmt.video.i_width -= 1;
 285
 286             i_padd = (fmt.video.i_width - i_canvas_width) / 2;
 287             i_offset = (i_padd & 1);
 288             snprintf( psz_croppadd, 100, "croppadd{cropleft=%d,cropright=%d}",
 289                       i_padd - i_offset, i_padd + i_offset );
 290         }
 291         else
 292         {
 293             /* The canvas has a shorter aspect than the subpicture:
 294              *  ie, crop the [scaled] subpicture vertically */
 295             fmt.video.i_height = i_canvas_height
 296                                * i_canvas_aspect
 297                                / i_fmt_in_aspect;
 298             if( fmt.video.i_height & 1 ) fmt.video.i_height -= 1;
 299
 300             i_padd = (fmt.video.i_height - i_canvas_height) / 2;
 301             i_offset = (i_padd & 1);
 302             snprintf( psz_croppadd, 100, "croppadd{croptop=%d,cropbottom=%d}",
 303                       i_padd - i_offset, i_padd + i_offset );
 304         }
 305     }
 306
 307     /* xxx, should the clean area include the letter-boxing?
 308      *  probably not, as some codecs can make use of that information
 309      *  and it should be a scaled version of the input clean area
 310      *   -- davidf */
 311     fmt.video.i_visible_width = fmt.video.i_width;
 312     fmt.video.i_visible_height = fmt.video.i_height;
 313
 314     filter_chain_Reset( p_sys->p_chain, &p_filter->fmt_in, &fmt );
 315     /* Append scaling module */
 316     filter_chain_AppendFilter( p_sys->p_chain, NULL, NULL, NULL, NULL );
 317     /* Append padding module */
 318     filter_chain_AppendFromString( p_sys->p_chain, psz_croppadd );
 319
 320     fmt = *filter_chain_GetFmtOut( p_sys->p_chain );
 321     es_format_Copy( &p_filter->fmt_out, &fmt );
 322
 323     p_filter->fmt_out.video.i_sar_num =
 324         i_canvas_aspect    * p_filter->fmt_out.video.i_height;
 325     p_filter->fmt_out.video.i_sar_den =
 326         VOUT_ASPECT_FACTOR * p_filter->fmt_out.video.i_width;
 327
 328     if( p_filter->fmt_out.video.i_width != i_canvas_width
 329      || p_filter->fmt_out.video.i_height != i_canvas_height )
 330     {
 331         msg_Warn( p_filter, "Looks like something went wrong. "
 332                   "Output size is %dx%d while we asked for %dx%d",
 333                   p_filter->fmt_out.video.i_width,
 334                   p_filter->fmt_out.video.i_height,
 335                   i_canvas_width, i_canvas_height );
 336     }
 337
 338     p_filter->pf_video_filter = Filter;
 339
 340     return VLC_SUCCESS;
 341 }
 342
 343 /*****************************************************************************
 344  *
 345  *****************************************************************************/
 346 static void Destroy( vlc_object_t *p_this )
 347 {
 348     filter_t *p_filter = (filter_t *)p_this;
 349     filter_chain_Delete( p_filter->p_sys->p_chain );
 350     free( p_filter->p_sys );
 351 }
 352
 353 /*****************************************************************************
 354  *
 355  *****************************************************************************/
 356 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 357 {
 358     return filter_chain_VideoFilter( p_filter->p_sys->p_chain, p_pic );
 359 }
 360
 361 /*****************************************************************************
 362  *
 363  *****************************************************************************/
 364 static picture_t *video_new( filter_t *p_filter )
 365 {
 366     return filter_NewPicture( (filter_t*)p_filter->p_owner );
 367 }
 368
 369 static void video_del( filter_t *p_filter, picture_t *p_pic )
 370 {
 371     return filter_DeletePicture( (filter_t*)p_filter->p_owner, p_pic );
 372 }
 373
 374 static int alloc_init( filter_t *p_filter, void *p_data )
 375 {
 376     p_filter->p_owner = p_data;
 377     p_filter->pf_video_buffer_new = video_new;
 378     p_filter->pf_video_buffer_del = video_del;
 379     return VLC_SUCCESS;
 380 }