FFmpeg4/libswscale/gamma.c

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2023-07-02 12:20:28 +00:00
/*
* Copyright (C) 2015 Pedro Arthur <bygrandao@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "swscale_internal.h"
typedef struct GammaContext
{
uint16_t *table;
} GammaContext;
// gamma_convert expects 16 bit rgb format
// it writes directly in src slice thus it must be modifiable (done through cascade context)
static int gamma_convert(SwsContext *c, SwsFilterDescriptor *desc, int sliceY, int sliceH)
{
GammaContext *instance = desc->instance;
uint16_t *table = instance->table;
int srcW = desc->src->width;
int i;
for (i = 0; i < sliceH; ++i) {
uint8_t ** src = desc->src->plane[0].line;
int src_pos = sliceY+i - desc->src->plane[0].sliceY;
uint16_t *src1 = (uint16_t*)*(src+src_pos);
int j;
for (j = 0; j < srcW; ++j) {
uint16_t r = AV_RL16(src1 + j*4 + 0);
uint16_t g = AV_RL16(src1 + j*4 + 1);
uint16_t b = AV_RL16(src1 + j*4 + 2);
AV_WL16(src1 + j*4 + 0, table[r]);
AV_WL16(src1 + j*4 + 1, table[g]);
AV_WL16(src1 + j*4 + 2, table[b]);
}
}
return sliceH;
}
int ff_init_gamma_convert(SwsFilterDescriptor *desc, SwsSlice * src, uint16_t *table)
{
GammaContext *li = av_malloc(sizeof(GammaContext));
if (!li)
return AVERROR(ENOMEM);
li->table = table;
desc->instance = li;
desc->src = src;
desc->dst = NULL;
desc->process = &gamma_convert;
return 0;
}