git.sesse.net Git - vlc/blob - modules/video_filter/sepia.c

   1 /*****************************************************************************
   2  * sepia.c : Sepia video plugin for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2010 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Branko Kokanovic <branko.kokanovic@gmail.com>
   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 <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_filter.h>
  35 #include <vlc_cpu.h>
  36
  37 #include <assert.h>
  38 #include "filter_picture.h"
  39
  40 /*****************************************************************************
  41  * Local prototypes
  42  *****************************************************************************/
  43 static int  Create      ( vlc_object_t * );
  44 static void Destroy     ( vlc_object_t * );
  45
  46 static void RVSepia( picture_t *, picture_t *, int );
  47 static void PlanarI420Sepia( picture_t *, picture_t *, int);
  48 static void PackedYUVSepia( picture_t *, picture_t *, int);
  49 static picture_t *Filter( filter_t *, picture_t * );
  50 inline void Sepia8ySSE2( uint8_t *, const uint8_t *, int );
  51 static const char *const ppsz_filter_options[] = {
  52     "intensity", NULL
  53 };
  54
  55 /*****************************************************************************
  56  * Module descriptor
  57  *****************************************************************************/
  58 #define SEPIA_INTENSITY_TEXT N_("Sepia intensity")
  59 #define SEPIA_INTENSITY_LONGTEXT N_("Intensity of sepia effect" )
  60
  61 #define CFG_PREFIX "sepia-"
  62
  63 vlc_module_begin ()
  64     set_description( N_("Sepia video filter") )
  65     set_shortname( N_("Sepia" ) )
  66     set_help( N_("Gives video a warmer tone by applying sepia effect") )
  67     set_category( CAT_VIDEO )
  68     set_subcategory( SUBCAT_VIDEO_VFILTER )
  69     set_capability( "video filter2", 0 )
  70     add_integer_with_range( CFG_PREFIX "intensity", 120, 0, 255,
  71                            SEPIA_INTENSITY_TEXT, SEPIA_INTENSITY_LONGTEXT,
  72                            false )
  73     set_callbacks( Create, Destroy )
  74 vlc_module_end ()
  75
  76 /*****************************************************************************
  77  * callback prototypes
  78  *****************************************************************************/
  79 static int FilterCallback( vlc_object_t *, char const *,
  80                            vlc_value_t, vlc_value_t, void * );
  81
  82 typedef void (*SepiaFunction)( picture_t *, picture_t *, int );
  83
  84 static const struct
  85 {
  86     vlc_fourcc_t i_chroma;
  87     SepiaFunction pf_sepia;
  88 } p_sepia_cfg[] = {
  89     { VLC_CODEC_I420, PlanarI420Sepia },
  90     { VLC_CODEC_RGB24, RVSepia },
  91     { VLC_CODEC_RGB32, RVSepia },
  92     { VLC_CODEC_UYVY, PackedYUVSepia },
  93     { VLC_CODEC_VYUY, PackedYUVSepia },
  94     { VLC_CODEC_YUYV, PackedYUVSepia },
  95     { VLC_CODEC_YVYU, PackedYUVSepia },
  96     { 0, NULL }
  97 };
  98
  99 /*****************************************************************************
 100  * filter_sys_t: adjust filter method descriptor
 101  *****************************************************************************/
 102 struct filter_sys_t
 103 {
 104     SepiaFunction pf_sepia;
 105     int i_intensity;
 106     vlc_spinlock_t lock;
 107 };
 108
 109 /*****************************************************************************
 110  * Create: allocates Sepia video thread output method
 111  *****************************************************************************
 112  * This function allocates and initializes a Sepia vout method.
 113  *****************************************************************************/
 114 static int Create( vlc_object_t *p_this )
 115 {
 116     filter_t *p_filter = (filter_t *)p_this;
 117     filter_sys_t *p_sys;
 118
 119     /* Allocate structure */
 120     p_sys = p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 121     if( p_filter->p_sys == NULL )
 122         return VLC_ENOMEM;
 123
 124     p_sys->pf_sepia = NULL;
 125
 126     for( int i = 0; p_sepia_cfg[i].i_chroma != 0; i++ )
 127     {
 128         if( p_sepia_cfg[i].i_chroma != p_filter->fmt_in.video.i_chroma )
 129             continue;
 130         p_sys->pf_sepia = p_sepia_cfg[i].pf_sepia;
 131     }
 132
 133     if( p_sys->pf_sepia == NULL )
 134     {
 135         msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
 136                 (char*)&(p_filter->fmt_in.video.i_chroma) );
 137         free( p_sys );
 138         return VLC_EGENERIC;
 139     }
 140
 141     config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
 142                        p_filter->p_cfg );
 143     p_sys->i_intensity= var_CreateGetIntegerCommand( p_filter,
 144                        CFG_PREFIX "intensity" );
 145
 146     vlc_spin_init( &p_sys->lock );
 147
 148     var_AddCallback( p_filter, CFG_PREFIX "intensity", FilterCallback, NULL );
 149
 150     p_filter->pf_video_filter = Filter;
 151
 152     return VLC_SUCCESS;
 153 }
 154
 155 /*****************************************************************************
 156  * Destroy: destroy sepia video thread output method
 157  *****************************************************************************
 158  * Terminate an output method
 159  *****************************************************************************/
 160 static void Destroy( vlc_object_t *p_this )
 161 {
 162     filter_t *p_filter = (filter_t *)p_this;
 163
 164     var_DelCallback( p_filter, CFG_PREFIX "intensity", FilterCallback, NULL );
 165
 166     vlc_spin_destroy( &p_filter->p_sys->lock );
 167     free( p_filter->p_sys );
 168 }
 169
 170 /*****************************************************************************
 171  * Render: displays previously rendered output
 172  *****************************************************************************
 173  * This function send the currently rendered image to sepia image, waits
 174  * until it is displayed and switch the two rendering buffers, preparing next
 175  * frame.
 176  *****************************************************************************/
 177 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 178 {
 179     picture_t *p_outpic;
 180     int intensity;
 181
 182     if( !p_pic ) return NULL;
 183
 184     filter_sys_t *p_sys = p_filter->p_sys;
 185     vlc_spin_lock( &p_sys->lock );
 186     intensity = p_sys->i_intensity;
 187     vlc_spin_unlock( &p_sys->lock );
 188
 189     p_outpic = filter_NewPicture( p_filter );
 190     if( !p_outpic )
 191     {
 192         msg_Warn( p_filter, "can't get output picture" );
 193         picture_Release( p_pic );
 194         return NULL;
 195     }
 196
 197     p_sys->pf_sepia( p_pic, p_outpic, intensity );
 198
 199     return CopyInfoAndRelease( p_outpic, p_pic );
 200 }
 201
 202 /*****************************************************************************
 203  * PlanarI420Sepia: Applies sepia to one frame of the planar I420 video
 204  *****************************************************************************
 205  * This function applies sepia effect to one frame of the video by iterating
 206  * through video lines. We iterate for every two lines and for every two pixels
 207  * in line to calculate new sepia values for four y components as well for u
 208  * and v components.
 209  *****************************************************************************/
 210 static void PlanarI420Sepia( picture_t *p_pic, picture_t *p_outpic,
 211                                int i_intensity )
 212 {
 213     // prepared values to copy for U and V channels
 214     const uint8_t filling_const_8u = 128 - i_intensity / 6;
 215     const uint8_t filling_const_8v = 128 + i_intensity / 14;
 216
 217 #if defined(CAN_COMPILE_SSE2)
 218     if (vlc_CPU() & CPU_CAPABILITY_SSE2)
 219     {
 220         /* prepared value for faster broadcasting in xmm register */
 221         int i_intensity_spread = 0x10001 * (uint8_t) i_intensity;
 222
 223         __asm__ volatile(
 224             "pxor      %%xmm7, %%xmm7\n"
 225         ::);
 226
 227         /* iterate for every two visible line in the frame */
 228         for (int y = 0; y < p_pic->p[Y_PLANE].i_visible_lines - 1; y += 2)
 229         {
 230             const int i_dy_line1_start = y * p_outpic->p[Y_PLANE].i_pitch;
 231             const int i_dy_line2_start =
 232             (y + 1) * p_outpic->p[Y_PLANE].i_pitch;
 233             const int i_du_line_start =
 234             (y / 2) * p_outpic->p[U_PLANE].i_pitch;
 235             const int i_dv_line_start =
 236             (y / 2) * p_outpic->p[V_PLANE].i_pitch;
 237             int x = 0;
 238             /* iterate for every visible line in the frame (eight values at once) */
 239             for ( ; x < p_pic->p[Y_PLANE].i_visible_pitch - 15; x += 16 )
 240             {
 241                 /* Compute yellow channel values with asm function */
 242                 Sepia8ySSE2(
 243                     &p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x],
 244                     &p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x],
 245                     i_intensity_spread );
 246                 Sepia8ySSE2(
 247                     &p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x],
 248                     &p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x],
 249                     i_intensity_spread );
 250                 Sepia8ySSE2(
 251                     &p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 8],
 252                     &p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 8],
 253                     i_intensity_spread );
 254                 Sepia8ySSE2(
 255                     &p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 8],
 256                     &p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 8],
 257                     i_intensity_spread );
 258                 /* Copy precomputed values to destination memory location */
 259                 vlc_memset(
 260                     &p_outpic->p[U_PLANE].p_pixels[i_du_line_start + (x / 2)],
 261                     filling_const_8u, 8 );
 262                 vlc_memset(
 263                     &p_outpic->p[V_PLANE].p_pixels[i_dv_line_start + (x / 2)],
 264                     filling_const_8v, 8 );
 265             }
 266             /* Completing the job, the cycle above takes really big chunks, so
 267               this makes sure the job will be done completely */
 268             for ( ; x < p_pic->p[Y_PLANE].i_visible_pitch - 1; x += 2 )
 269             {
 270                 // y = y - y/4 {to prevent overflow} + intensity / 4
 271                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] =
 272                     p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] -
 273                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] >> 2) +
 274                     (i_intensity >> 2);
 275                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] =
 276                     p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] -
 277                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] >> 2) +
 278                     (i_intensity >> 2);
 279                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] =
 280                     p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] -
 281                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] >> 2) +
 282                     (i_intensity >> 2);
 283                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] =
 284                     p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] -
 285                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] >> 2) +
 286                     (i_intensity >> 2);
 287                 // u = 128 {half => B&W} - intensity / 6
 288                 p_outpic->p[U_PLANE].p_pixels[i_du_line_start + (x / 2)] =
 289                     filling_const_8u;
 290                 // v = 128 {half => B&W} + intensity / 14
 291                 p_outpic->p[V_PLANE].p_pixels[i_dv_line_start + (x / 2)] =
 292                     filling_const_8v;
 293             }
 294         }
 295     }
 296     else
 297 #endif
 298     {
 299         /* iterate for every two visible line in the frame */
 300         for( int y = 0; y < p_pic->p[Y_PLANE].i_visible_lines - 1; y += 2)
 301         {
 302             const int i_dy_line1_start = y * p_outpic->p[Y_PLANE].i_pitch;
 303             const int i_dy_line2_start = ( y + 1 ) * p_outpic->p[Y_PLANE].i_pitch;
 304             const int i_du_line_start = (y/2) * p_outpic->p[U_PLANE].i_pitch;
 305             const int i_dv_line_start = (y/2) * p_outpic->p[V_PLANE].i_pitch;
 306             // to prevent sigsegv if one pic is smaller (theoretically)
 307             int i_picture_size_limit = p_pic->p[Y_PLANE].i_visible_pitch
 308                       < p_outpic->p[Y_PLANE].i_visible_pitch
 309                       ? (p_pic->p[Y_PLANE].i_visible_pitch - 1) :
 310                       (p_outpic->p[Y_PLANE].i_visible_pitch - 1);
 311             /* iterate for every two visible line in the frame */
 312             for( int x = 0; x < i_picture_size_limit; x += 2)
 313             {
 314                 // y = y - y/4 {to prevent overflow} + intensity / 4
 315                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] =
 316                     p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] -
 317                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x] >> 2) +
 318                     (i_intensity >> 2);
 319                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] =
 320                     p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] -
 321                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line1_start + x + 1] >> 2) +
 322                     (i_intensity >> 2);
 323                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] =
 324                     p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] -
 325                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x] >> 2) +
 326                     (i_intensity >> 2);
 327                 p_outpic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] =
 328                     p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] -
 329                     (p_pic->p[Y_PLANE].p_pixels[i_dy_line2_start + x + 1] >> 2) +
 330                     (i_intensity >> 2);
 331                 // u = 128 {half => B&W} - intensity / 6
 332                 p_outpic->p[U_PLANE].p_pixels[i_du_line_start + (x / 2)] =
 333                     filling_const_8u;
 334                 // v = 128 {half => B&W} + intensity / 14
 335                 p_outpic->p[V_PLANE].p_pixels[i_dv_line_start + (x / 2)] =
 336                     filling_const_8v;
 337             }
 338         }
 339     }
 340 }
 341
 342 /*****************************************************************************
 343  * PackedYUVSepia: Applies sepia to one frame of the packed YUV video
 344  *****************************************************************************
 345  * This function applies sepia effext to one frame of the video by iterating
 346  * through video lines. In every pass, we calculate new values for pixels
 347  * (UYVY, VYUY, YUYV and YVYU formats are supported)
 348  *****************************************************************************/
 349 static void PackedYUVSepia( picture_t *p_pic, picture_t *p_outpic,
 350                            int i_intensity )
 351 {
 352     uint8_t *p_in, *p_in_end, *p_line_end, *p_out;
 353     int i_yindex = 1, i_uindex = 2, i_vindex = 0;
 354
 355     GetPackedYuvOffsets( p_outpic->format.i_chroma,
 356                         &i_yindex, &i_uindex, &i_vindex );
 357
 358     // prepared values to copy for U and V channels
 359     const uint8_t filling_const_8u = 128 - i_intensity / 6;
 360     const uint8_t filling_const_8v = 128 + i_intensity / 14;
 361
 362     p_in = p_pic->p[0].p_pixels;
 363     p_in_end = p_in + p_pic->p[0].i_visible_lines
 364         * p_pic->p[0].i_pitch;
 365     p_out = p_outpic->p[0].p_pixels;
 366
 367     {
 368         while( p_in < p_in_end )
 369         {
 370             p_line_end = p_in + p_pic->p[0].i_visible_pitch;
 371             while( p_in < p_line_end )
 372             {
 373                 /* calculate new, sepia values */
 374                 p_out[i_yindex] =
 375                     p_in[i_yindex] - (p_in[i_yindex] >> 2) + (i_intensity >> 2);
 376                 p_out[i_yindex + 2] =
 377                     p_in[i_yindex + 2] - (p_in[i_yindex + 2] >> 2)
 378                     + (i_intensity >> 2);
 379                 p_out[i_uindex] = filling_const_8u;
 380                 p_out[i_vindex] = filling_const_8v;
 381                 p_in += 4;
 382                 p_out += 4;
 383             }
 384             p_in += p_pic->p[0].i_pitch - p_pic->p[0].i_visible_pitch;
 385             p_out += p_outpic->p[0].i_pitch
 386                 - p_outpic->p[0].i_visible_pitch;
 387         }
 388     }
 389 }
 390
 391 /*****************************************************************************
 392  * RVSepia: Applies sepia to one frame of the RV24/RV32 video
 393  *****************************************************************************
 394  * This function applies sepia effect to one frame of the video by iterating
 395  * through video lines and calculating new values for every byte in chunks of
 396  * 3 (RV24) or 4 (RV32) bytes.
 397  *****************************************************************************/
 398 static void RVSepia( picture_t *p_pic, picture_t *p_outpic, int i_intensity )
 399 {
 400 #define SCALEBITS 10
 401 #define ONE_HALF  (1 << (SCALEBITS - 1))
 402 #define FIX(x)    ((int) ((x) * (1<<SCALEBITS) + 0.5))
 403     uint8_t *p_in, *p_in_end, *p_line_end, *p_out;
 404     bool b_isRV32 = p_pic->format.i_chroma == VLC_CODEC_RGB32;
 405     int i_rindex = 0, i_gindex = 1, i_bindex = 2;
 406
 407     GetPackedRgbIndexes( &p_outpic->format, &i_rindex, &i_gindex, &i_bindex );
 408
 409     p_in = p_pic->p[0].p_pixels;
 410     p_in_end = p_in + p_pic->p[0].i_visible_lines
 411         * p_pic->p[0].i_pitch;
 412     p_out = p_outpic->p[0].p_pixels;
 413
 414     /* Precompute values constant for this certain i_intensity, using the same
 415      * formula as YUV functions above */
 416     uint8_t r_intensity = (( FIX( 1.40200 * 255.0 / 224.0 ) * (i_intensity * 14)
 417                         + ONE_HALF )) >> SCALEBITS;
 418     uint8_t g_intensity = (( - FIX(0.34414*255.0/224.0) * ( - i_intensity / 6 )
 419                         - FIX( 0.71414 * 255.0 / 224.0) * ( i_intensity * 14 )
 420                         + ONE_HALF )) >> SCALEBITS;
 421     uint8_t b_intensity = (( FIX( 1.77200 * 255.0 / 224.0) * ( - i_intensity / 6 )
 422                         + ONE_HALF )) >> SCALEBITS;
 423
 424     while (p_in < p_in_end)
 425     {
 426         p_line_end = p_in + p_pic->p[0].i_visible_pitch;
 427         while (p_in < p_line_end)
 428         {
 429             /* do sepia: this calculation is based on the formula to calculate
 430              * YUV->RGB and RGB->YUV (in filter_picture.h) mode and that
 431              * y = y - y/4 + intensity/4 . As Y is the only channel that changes
 432              * through the whole image. After that, precomputed values are added
 433              * for each RGB channel and saved in the output image.
 434              * FIXME: needs cleanup */
 435             uint8_t i_y = ((( 66 * p_in[i_rindex] + 129 * p_in[i_gindex] +  25
 436                       * p_in[i_bindex] + 128 ) >> 8 ) * FIX(255.0/219.0))
 437                       - (((( 66 * p_in[i_rindex] + 129 * p_in[i_gindex] + 25
 438                       * p_in[i_bindex] + 128 ) >> 8 )
 439                       * FIX( 255.0 / 219.0 )) >> 2 ) + ( i_intensity >> 2 );
 440             p_out[i_rindex] = vlc_uint8(i_y + r_intensity);
 441             p_out[i_gindex] = vlc_uint8(i_y + g_intensity);
 442             p_out[i_bindex] = vlc_uint8(i_y + b_intensity);
 443             p_in += 3;
 444             p_out += 3;
 445             /* for rv32 we take 4 chunks at the time */
 446             if (b_isRV32) {
 447             /* alpha channel stays the same */
 448             *p_out++ = *p_in++;
 449             }
 450         }
 451
 452         p_in += p_pic->p[0].i_pitch - p_pic->p[0].i_visible_pitch;
 453         p_out += p_outpic->p[0].i_pitch
 454             - p_outpic->p[0].i_visible_pitch;
 455     }
 456 #undef SCALEBITS
 457 #undef ONE_HALF
 458 #undef FIX
 459 }
 460
 461 /*****************************************************************************
 462  * Sepia8ySSE2
 463  *****************************************************************************
 464  * This function applies sepia effect to eight bytes of yellow using SSE4.1
 465  * instructions. It copies those 8 bytes to 128b register and fills the gaps
 466  * with zeroes and following operations are made with word-operating instructs.
 467  *****************************************************************************/
 468 inline void Sepia8ySSE2(uint8_t * dst, const uint8_t * src,
 469                          int i_intensity_spread)
 470 {
 471 #if defined(CAN_COMPILE_SSE2)
 472     __asm__ volatile (
 473         // y = y - y / 4 + i_intensity / 4
 474         "movq            (%1), %%xmm1\n"
 475         "punpcklbw     %%xmm7, %%xmm1\n"
 476         "movq            (%1), %%xmm2\n" // store bytes as words with 0s in between
 477         "punpcklbw     %%xmm7, %%xmm2\n"
 478         "movd              %2, %%xmm3\n"
 479         "pshufd    $0, %%xmm3, %%xmm3\n"
 480         "psrlw             $2, %%xmm2\n"    // rotate right 2
 481         "psubusb       %%xmm1, %%xmm2\n"    // subtract
 482         "psrlw             $2, %%xmm3\n"
 483         "paddsb        %%xmm1, %%xmm3\n"    // add
 484         "packuswb      %%xmm2, %%xmm1\n"    // pack back to bytes
 485         "movq          %%xmm1, (%0)  \n"    // load to dest
 486         :
 487         :"r" (dst), "r"(src), "r"(i_intensity_spread)
 488         :"memory");
 489 #endif
 490 }
 491
 492 static int FilterCallback ( vlc_object_t *p_this, char const *psz_var,
 493                             vlc_value_t oldval, vlc_value_t newval,
 494                             void *p_data )
 495 {
 496     VLC_UNUSED(psz_var); VLC_UNUSED(oldval); VLC_UNUSED(p_data);
 497     filter_t *p_filter = (filter_t*)p_this;
 498     filter_sys_t *p_sys = p_filter->p_sys;
 499
 500     vlc_spin_lock( &p_sys->lock );
 501     p_sys->i_intensity = newval.i_int;
 502     vlc_spin_unlock( &p_sys->lock );
 503
 504     return VLC_SUCCESS;
 505 }