modules/video_filter/canvas.c

   1 /*****************************************************************************
   2  * canvas.c : automatically resize and padd a video to fit in canvas
   3  *****************************************************************************
   4  * Copyright (C) 2008 VLC authors and VideoLAN
   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 it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * 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 #include <vlc_picture.h>
  38
  39 /*****************************************************************************
  40  * Local and extern prototypes.
  41  *****************************************************************************/
  42 static int  Activate( vlc_object_t * );
  43 static void Destroy( vlc_object_t * );
  44 static picture_t *Filter( filter_t *, picture_t * );
  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 filter", 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,
 115                             WIDTH_TEXT, WIDTH_LONGTEXT, false )
 116     add_integer_with_range( CFG_PREFIX "height", 0, 0, INT_MAX,
 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 static picture_t *video_new( filter_t *p_filter )
 136 {
 137     return filter_NewPicture( p_filter->owner.sys );
 138 }
 139
 140 /*****************************************************************************
 141  *
 142  *****************************************************************************/
 143 static int Activate( vlc_object_t *p_this )
 144 {
 145     filter_t *p_filter = (filter_t *)p_this;
 146     unsigned i_canvas_width; /* visible width of output canvas */
 147     unsigned i_canvas_height; /* visible height of output canvas */
 148     unsigned i_canvas_aspect; /* canvas PictureAspectRatio */
 149     es_format_t fmt; /* target format after up/down conversion */
 150     char psz_croppadd[100];
 151     int i_padd,i_offset;
 152     char *psz_aspect, *psz_parser;
 153     bool b_padd;
 154     unsigned i_fmt_in_aspect;
 155
 156     if( !p_filter->b_allow_fmt_out_change )
 157     {
 158         msg_Err( p_filter, "Picture format change isn't allowed" );
 159         return VLC_EGENERIC;
 160     }
 161
 162     if( p_filter->fmt_in.video.i_chroma != p_filter->fmt_out.video.i_chroma )
 163     {
 164         msg_Err( p_filter, "Input and output chromas don't match" );
 165         return VLC_EGENERIC;
 166     }
 167
 168     config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
 169                        p_filter->p_cfg );
 170
 171     i_canvas_width = var_CreateGetInteger( p_filter, CFG_PREFIX "width" );
 172     i_canvas_height = var_CreateGetInteger( p_filter, CFG_PREFIX "height" );
 173
 174     if( i_canvas_width == 0 || i_canvas_height == 0 )
 175     {
 176         msg_Err( p_filter, "Width and height options must be set" );
 177         return VLC_EGENERIC;
 178     }
 179
 180     if( i_canvas_width & 1 || i_canvas_height & 1 )
 181     {
 182         /* If this restriction were ever relaxed, it is very important to
 183          * get the field polatiry correct */
 184         msg_Err( p_filter, "Width and height options must be even integers" );
 185         return VLC_EGENERIC;
 186     }
 187
 188     if( p_filter->fmt_in.video.i_sar_num )
 189         i_fmt_in_aspect = (int64_t)p_filter->fmt_in.video.i_sar_num *
 190                       p_filter->fmt_in.video.i_visible_width *
 191                       VOUT_ASPECT_FACTOR /
 192                       p_filter->fmt_in.video.i_sar_den /
 193                       p_filter->fmt_in.video.i_visible_height;
 194     else
 195         i_fmt_in_aspect = (int64_t)p_filter->fmt_in.video.i_visible_width *
 196                       VOUT_ASPECT_FACTOR /
 197                       p_filter->fmt_in.video.i_visible_height;
 198
 199     psz_aspect = var_CreateGetNonEmptyString( p_filter, CFG_PREFIX "aspect" );
 200     if( psz_aspect )
 201     {
 202         psz_parser = strchr( psz_aspect, ':' );
 203         int numerator = atoi( psz_aspect );
 204         int denominator = psz_parser ? atoi( psz_parser+1 ) : 0;
 205         denominator = denominator == 0 ? 1 : denominator;
 206         i_canvas_aspect = numerator * VOUT_ASPECT_FACTOR / denominator;
 207         free( psz_aspect );
 208
 209         if( numerator <= 0 || denominator < 0 )
 210         {
 211             msg_Err( p_filter, "Aspect ratio must be strictly positive" );
 212             return VLC_EGENERIC;
 213         }
 214     }
 215     else
 216     {
 217         /* if there is no user supplied aspect ratio, assume the canvas
 218          * has the same sample aspect ratio as the subpicture */
 219         /* aspect = subpic_sar * canvas_width / canvas_height
 220          *  where subpic_sar = subpic_ph * subpic_par / subpic_pw */
 221         i_canvas_aspect = (uint64_t) p_filter->fmt_in.video.i_visible_height
 222                         * i_fmt_in_aspect
 223                         * i_canvas_width
 224                         / (i_canvas_height * p_filter->fmt_in.video.i_visible_width);
 225     }
 226
 227     b_padd = var_CreateGetBool( p_filter, CFG_PREFIX "padd" );
 228
 229     filter_sys_t *p_sys = (filter_sys_t *)malloc( sizeof( filter_sys_t ) );
 230     if( !p_sys )
 231         return VLC_ENOMEM;
 232     p_filter->p_sys = p_sys;
 233
 234     filter_owner_t owner = {
 235         .sys = p_filter,
 236         .video = {
 237             .buffer_new = video_new,
 238         },
 239     };
 240
 241     p_sys->p_chain = filter_chain_NewVideo( p_filter, true, &owner );
 242     if( !p_sys->p_chain )
 243     {
 244         msg_Err( p_filter, "Could not allocate filter chain" );
 245         free( p_sys );
 246         return VLC_EGENERIC;
 247     }
 248
 249     es_format_Copy( &fmt, &p_filter->fmt_in );
 250
 251     /* one dimension will end up with one of the following: */
 252     fmt.video.i_visible_width = i_canvas_width;
 253     fmt.video.i_visible_height = i_canvas_height;
 254
 255     if( b_padd )
 256     {
 257         /* Padd */
 258         if( i_canvas_aspect > i_fmt_in_aspect )
 259         {
 260             /* The canvas has a wider aspect than the subpicture:
 261              *  ie, pillarbox the [scaled] subpicture */
 262             /* The following is derived form:
 263              * width = upconverted_subpic_height * subpic_par / canvas_sar
 264              *  where canvas_sar = canvas_width / (canvas_height * canvas_par)
 265              * then simplify */
 266             fmt.video.i_visible_width = i_canvas_width
 267                               * i_fmt_in_aspect
 268                               / i_canvas_aspect;
 269             if( fmt.video.i_visible_width & 1 ) fmt.video.i_visible_width -= 1;
 270
 271             i_padd = (i_canvas_width - fmt.video.i_visible_width) / 2;
 272             i_offset = (i_padd & 1);
 273             snprintf( psz_croppadd, 100, "croppadd{paddleft=%d,paddright=%d}",
 274                       i_padd - i_offset, i_padd + i_offset );
 275         }
 276         else
 277         {
 278             /* The canvas has a taller aspect than the subpicture:
 279              *  ie, letterbox the [scaled] subpicture */
 280             fmt.video.i_visible_height = i_canvas_height
 281                                * i_canvas_aspect
 282                                / i_fmt_in_aspect;
 283             if( fmt.video.i_visible_height & 1 ) fmt.video.i_visible_height -= 1;
 284
 285             i_padd = (i_canvas_height - fmt.video.i_visible_height ) / 2;
 286             i_offset = (i_padd & 1);
 287             snprintf( psz_croppadd, 100, "croppadd{paddtop=%d,paddbottom=%d}",
 288                       i_padd - i_offset, i_padd + i_offset );
 289         }
 290     }
 291     else
 292     {
 293         /* Crop */
 294         if( i_canvas_aspect < i_fmt_in_aspect )
 295         {
 296             /* The canvas has a narrower aspect than the subpicture:
 297              *  ie, crop the [scaled] subpicture horizontally */
 298             fmt.video.i_visible_width = i_canvas_width
 299                               * i_fmt_in_aspect
 300                               / i_canvas_aspect;
 301             if( fmt.video.i_visible_width & 1 ) fmt.video.i_visible_width -= 1;
 302
 303             i_padd = (fmt.video.i_visible_width - i_canvas_width) / 2;
 304             i_offset = (i_padd & 1);
 305             snprintf( psz_croppadd, 100, "croppadd{cropleft=%d,cropright=%d}",
 306                       i_padd - i_offset, i_padd + i_offset );
 307         }
 308         else
 309         {
 310             /* The canvas has a shorter aspect than the subpicture:
 311              *  ie, crop the [scaled] subpicture vertically */
 312             fmt.video.i_visible_height = i_canvas_height
 313                                * i_canvas_aspect
 314                                / i_fmt_in_aspect;
 315             if( fmt.video.i_visible_height & 1 ) fmt.video.i_visible_height -= 1;
 316
 317             i_padd = (fmt.video.i_visible_height - i_canvas_height) / 2;
 318             i_offset = (i_padd & 1);
 319             snprintf( psz_croppadd, 100, "croppadd{croptop=%d,cropbottom=%d}",
 320                       i_padd - i_offset, i_padd + i_offset );
 321         }
 322     }
 323
 324     /* xxx, should the clean area include the letter-boxing?
 325      *  probably not, as some codecs can make use of that information
 326      *  and it should be a scaled version of the input clean area
 327      *   -- davidf */
 328     fmt.video.i_width = p_filter->fmt_in.video.i_width * fmt.video.i_visible_width / p_filter->fmt_in.video.i_visible_width;
 329     fmt.video.i_height = p_filter->fmt_in.video.i_height * fmt.video.i_visible_height / p_filter->fmt_in.video.i_visible_height;
 330
 331     filter_chain_Reset( p_sys->p_chain, &p_filter->fmt_in, &fmt );
 332     /* Append scaling module */
 333     if ( !filter_chain_AppendConverter( p_sys->p_chain, NULL, NULL ) )
 334     {
 335         msg_Err( p_filter, "Could not append scaling filter" );
 336         free( p_sys );
 337         return VLC_EGENERIC;
 338     }
 339
 340     /* Append croppadd module if we actually do cropping or padding instead of just scaling*/
 341     if( i_padd > 0 )
 342     {
 343         if ( !filter_chain_AppendFromString( p_sys->p_chain, psz_croppadd ) )
 344         {
 345             msg_Err( p_filter, "Could not append cropadd filter" );
 346             filter_chain_Delete( p_sys->p_chain );
 347             free( p_sys );
 348             return VLC_EGENERIC;
 349         }
 350     }
 351
 352     fmt = *filter_chain_GetFmtOut( p_sys->p_chain );
 353     es_format_Copy( &p_filter->fmt_out, &fmt );
 354
 355     vlc_ureduce( &p_filter->fmt_out.video.i_sar_num,
 356         &p_filter->fmt_out.video.i_sar_den,
 357         i_canvas_aspect    * p_filter->fmt_out.video.i_visible_height,
 358         VOUT_ASPECT_FACTOR * p_filter->fmt_out.video.i_visible_width,
 359         0);
 360
 361     if( p_filter->fmt_out.video.i_visible_width != i_canvas_width
 362      || p_filter->fmt_out.video.i_visible_height != i_canvas_height )
 363     {
 364         msg_Warn( p_filter, "Looks like something went wrong. "
 365                   "Output size is %dx%d while we asked for %dx%d",
 366                   p_filter->fmt_out.video.i_visible_width,
 367                   p_filter->fmt_out.video.i_visible_height,
 368                   i_canvas_width, i_canvas_height );
 369     }
 370
 371     p_filter->pf_video_filter = Filter;
 372
 373     return VLC_SUCCESS;
 374 }
 375
 376 /*****************************************************************************
 377  *
 378  *****************************************************************************/
 379 static void Destroy( vlc_object_t *p_this )
 380 {
 381     filter_t *p_filter = (filter_t *)p_this;
 382     filter_chain_Delete( p_filter->p_sys->p_chain );
 383     free( p_filter->p_sys );
 384 }
 385
 386 /*****************************************************************************
 387  *
 388  *****************************************************************************/
 389 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 390 {
 391     return filter_chain_VideoFilter( p_filter->p_sys->p_chain, p_pic );
 392 }