libswscale/gamma.c

   1 /*
   2  * Copyright (C) 2015 Pedro Arthur <bygrandao@gmail.com>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "libavutil/mem.h"
  22 #include "swscale_internal.h"
  23
  24 typedef struct GammaContext
  25 {
  26     uint16_t *table;
  27 } GammaContext;
  28
  29 // gamma_convert expects 16 bit rgb format
  30 // it writes directly in src slice thus it must be modifiable (done through cascade context)
  31 static int gamma_convert(SwsInternal *c, SwsFilterDescriptor *desc, int sliceY, int sliceH)
  32 {
  33     GammaContext *instance = desc->instance;
  34     uint16_t *table = instance->table;
  35     int srcW = desc->src->width;
  36
  37     int i;
  38     for (i = 0; i < sliceH; ++i) {
  39         uint8_t ** src = desc->src->plane[0].line;
  40         int src_pos = sliceY+i - desc->src->plane[0].sliceY;
  41
  42         uint16_t *src1 = (uint16_t*)*(src+src_pos);
  43         int j;
  44         for (j = 0; j < srcW; ++j) {
  45             uint16_t r = AV_RL16(src1 + j*4 + 0);
  46             uint16_t g = AV_RL16(src1 + j*4 + 1);
  47             uint16_t b = AV_RL16(src1 + j*4 + 2);
  48
  49             AV_WL16(src1 + j*4 + 0, table[r]);
  50             AV_WL16(src1 + j*4 + 1, table[g]);
  51             AV_WL16(src1 + j*4 + 2, table[b]);
  52         }
  53
  54     }
  55     return sliceH;
  56 }
  57
  58
  59 int ff_init_gamma_convert(SwsFilterDescriptor *desc, SwsSlice * src, uint16_t *table)
  60 {
  61     GammaContext *li = av_malloc(sizeof(GammaContext));
  62     if (!li)
  63         return AVERROR(ENOMEM);
  64     li->table = table;
  65
  66     desc->instance = li;
  67     desc->src = src;
  68     desc->dst = NULL;
  69     desc->process = &gamma_convert;
  70
  71     return 0;
  72 }