2012-10-20 05:45:51 +00:00
/*
* Copyright ( c ) 2012 Jeremy Tran
* Copyright ( c ) 2001 Donald A . Graft
*
* This file is part of FFmpeg .
*
* FFmpeg is free software ; you can redistribute it and / or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation ; either version 2 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 General Public License for more details .
*
* You should have received a copy of the GNU 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 .
*/
/**
* @ file
* Histogram equalization filter , based on the VirtualDub filter by
* Donald A . Graft < neuron2 AT home DOT com > .
* Implements global automatic contrast adjustment by means of
* histogram equalization .
*/
# include "libavutil/common.h"
2015-08-18 00:45:35 +00:00
# include "libavutil/internal.h"
2012-10-20 05:45:51 +00:00
# include "libavutil/opt.h"
# include "libavutil/pixdesc.h"
# include "avfilter.h"
# include "drawutils.h"
# include "formats.h"
# include "internal.h"
# include "video.h"
// #define DEBUG
// Linear Congruential Generator, see "Numerical Recipes"
# define LCG_A 4096
# define LCG_C 150889
# define LCG_M 714025
# define LCG(x) (((x) * LCG_A + LCG_C) % LCG_M)
# define LCG_SEED 739187
enum HisteqAntibanding {
HISTEQ_ANTIBANDING_NONE = 0 ,
HISTEQ_ANTIBANDING_WEAK = 1 ,
HISTEQ_ANTIBANDING_STRONG = 2 ,
HISTEQ_ANTIBANDING_NB ,
} ;
2017-05-12 18:00:49 +00:00
typedef struct HisteqContext {
2012-10-20 05:45:51 +00:00
const AVClass * class ;
float strength ;
float intensity ;
2015-03-17 16:13:38 +00:00
int antibanding ; ///< HisteqAntibanding
2012-10-20 05:45:51 +00:00
int in_histogram [ 256 ] ; ///< input histogram
int out_histogram [ 256 ] ; ///< output histogram
int LUT [ 256 ] ; ///< lookup table derived from histogram[]
uint8_t rgba_map [ 4 ] ; ///< components position
int bpp ; ///< bytes per pixel
} HisteqContext ;
# define OFFSET(x) offsetof(HisteqContext, x)
# define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
# define CONST(name, help, val, unit) { name, help, 0, AV_OPT_TYPE_CONST, {.i64=val}, INT_MIN, INT_MAX, FLAGS, unit }
static const AVOption histeq_options [ ] = {
{ " strength " , " set the strength " , OFFSET ( strength ) , AV_OPT_TYPE_FLOAT , { . dbl = 0.2 } , 0 , 1 , FLAGS } ,
{ " intensity " , " set the intensity " , OFFSET ( intensity ) , AV_OPT_TYPE_FLOAT , { . dbl = 0.21 } , 0 , 1 , FLAGS } ,
{ " antibanding " , " set the antibanding level " , OFFSET ( antibanding ) , AV_OPT_TYPE_INT , { . i64 = HISTEQ_ANTIBANDING_NONE } , 0 , HISTEQ_ANTIBANDING_NB - 1 , FLAGS , " antibanding " } ,
CONST ( " none " , " apply no antibanding " , HISTEQ_ANTIBANDING_NONE , " antibanding " ) ,
CONST ( " weak " , " apply weak antibanding " , HISTEQ_ANTIBANDING_WEAK , " antibanding " ) ,
CONST ( " strong " , " apply strong antibanding " , HISTEQ_ANTIBANDING_STRONG , " antibanding " ) ,
{ NULL }
} ;
AVFILTER_DEFINE_CLASS ( histeq ) ;
2013-04-12 09:13:33 +00:00
static av_cold int init ( AVFilterContext * ctx )
2012-10-20 05:45:51 +00:00
{
HisteqContext * histeq = ctx - > priv ;
av_log ( ctx , AV_LOG_VERBOSE ,
" strength:%0.3f intensity:%0.3f antibanding:%d \n " ,
histeq - > strength , histeq - > intensity , histeq - > antibanding ) ;
return 0 ;
}
2021-09-29 13:57:43 +00:00
static const enum AVPixelFormat pix_fmts [ ] = {
AV_PIX_FMT_ARGB , AV_PIX_FMT_RGBA , AV_PIX_FMT_ABGR , AV_PIX_FMT_BGRA ,
AV_PIX_FMT_RGB24 , AV_PIX_FMT_BGR24 ,
AV_PIX_FMT_NONE
} ;
2012-10-20 05:45:51 +00:00
static int config_input ( AVFilterLink * inlink )
{
AVFilterContext * ctx = inlink - > dst ;
HisteqContext * histeq = ctx - > priv ;
const AVPixFmtDescriptor * pix_desc = av_pix_fmt_desc_get ( inlink - > format ) ;
histeq - > bpp = av_get_bits_per_pixel ( pix_desc ) / 8 ;
ff_fill_rgba_map ( histeq - > rgba_map , inlink - > format ) ;
return 0 ;
}
# define R 0
# define G 1
# define B 2
# define A 3
# define GET_RGB_VALUES(r, g, b, src, map) do { \
r = src [ x + map [ R ] ] ; \
g = src [ x + map [ G ] ] ; \
b = src [ x + map [ B ] ] ; \
} while ( 0 )
2013-03-10 00:30:30 +00:00
static int filter_frame ( AVFilterLink * inlink , AVFrame * inpic )
2012-10-20 05:45:51 +00:00
{
AVFilterContext * ctx = inlink - > dst ;
HisteqContext * histeq = ctx - > priv ;
AVFilterLink * outlink = ctx - > outputs [ 0 ] ;
int strength = histeq - > strength * 1000 ;
int intensity = histeq - > intensity * 1000 ;
int x , y , i , luthi , lutlo , lut , luma , oluma , m ;
2013-03-10 00:30:30 +00:00
AVFrame * outpic ;
2012-10-20 05:45:51 +00:00
unsigned int r , g , b , jran ;
uint8_t * src , * dst ;
2013-03-10 00:30:30 +00:00
outpic = ff_get_video_buffer ( outlink , outlink - > w , outlink - > h ) ;
2012-10-20 05:45:51 +00:00
if ( ! outpic ) {
2013-03-10 00:30:30 +00:00
av_frame_free ( & inpic ) ;
2012-10-20 05:45:51 +00:00
return AVERROR ( ENOMEM ) ;
}
2013-03-10 00:30:30 +00:00
av_frame_copy_props ( outpic , inpic ) ;
2012-10-20 05:45:51 +00:00
/* Seed random generator for antibanding. */
jran = LCG_SEED ;
/* Calculate and store the luminance and calculate the global histogram
based on the luminance . */
memset ( histeq - > in_histogram , 0 , sizeof ( histeq - > in_histogram ) ) ;
src = inpic - > data [ 0 ] ;
dst = outpic - > data [ 0 ] ;
for ( y = 0 ; y < inlink - > h ; y + + ) {
for ( x = 0 ; x < inlink - > w * histeq - > bpp ; x + = histeq - > bpp ) {
GET_RGB_VALUES ( r , g , b , src , histeq - > rgba_map ) ;
luma = ( 55 * r + 182 * g + 19 * b ) > > 8 ;
dst [ x + histeq - > rgba_map [ A ] ] = luma ;
histeq - > in_histogram [ luma ] + + ;
}
src + = inpic - > linesize [ 0 ] ;
dst + = outpic - > linesize [ 0 ] ;
}
# ifdef DEBUG
for ( x = 0 ; x < 256 ; x + + )
2015-08-18 00:45:35 +00:00
ff_dlog ( ctx , " in[%d]: %u \n " , x , histeq - > in_histogram [ x ] ) ;
2012-10-20 05:45:51 +00:00
# endif
/* Calculate the lookup table. */
histeq - > LUT [ 0 ] = histeq - > in_histogram [ 0 ] ;
/* Accumulate */
for ( x = 1 ; x < 256 ; x + + )
histeq - > LUT [ x ] = histeq - > LUT [ x - 1 ] + histeq - > in_histogram [ x ] ;
/* Normalize */
for ( x = 0 ; x < 256 ; x + + )
histeq - > LUT [ x ] = ( histeq - > LUT [ x ] * intensity ) / ( inlink - > h * inlink - > w ) ;
/* Adjust the LUT based on the selected strength. This is an alpha
mix of the calculated LUT and a linear LUT with gain 1. */
for ( x = 0 ; x < 256 ; x + + )
histeq - > LUT [ x ] = ( strength * histeq - > LUT [ x ] ) / 255 +
( ( 255 - strength ) * x ) / 255 ;
/* Output the equalized frame. */
memset ( histeq - > out_histogram , 0 , sizeof ( histeq - > out_histogram ) ) ;
src = inpic - > data [ 0 ] ;
dst = outpic - > data [ 0 ] ;
for ( y = 0 ; y < inlink - > h ; y + + ) {
for ( x = 0 ; x < inlink - > w * histeq - > bpp ; x + = histeq - > bpp ) {
luma = dst [ x + histeq - > rgba_map [ A ] ] ;
if ( luma = = 0 ) {
for ( i = 0 ; i < histeq - > bpp ; + + i )
dst [ x + i ] = 0 ;
histeq - > out_histogram [ 0 ] + + ;
} else {
lut = histeq - > LUT [ luma ] ;
if ( histeq - > antibanding ! = HISTEQ_ANTIBANDING_NONE ) {
if ( luma > 0 ) {
lutlo = histeq - > antibanding = = HISTEQ_ANTIBANDING_WEAK ?
( histeq - > LUT [ luma ] + histeq - > LUT [ luma - 1 ] ) / 2 :
histeq - > LUT [ luma - 1 ] ;
} else
lutlo = lut ;
if ( luma < 255 ) {
luthi = ( histeq - > antibanding = = HISTEQ_ANTIBANDING_WEAK ) ?
( histeq - > LUT [ luma ] + histeq - > LUT [ luma + 1 ] ) / 2 :
histeq - > LUT [ luma + 1 ] ;
} else
luthi = lut ;
if ( lutlo ! = luthi ) {
jran = LCG ( jran ) ;
lut = lutlo + ( ( luthi - lutlo + 1 ) * jran ) / LCG_M ;
}
}
GET_RGB_VALUES ( r , g , b , src , histeq - > rgba_map ) ;
if ( ( ( m = FFMAX3 ( r , g , b ) ) * lut ) / luma > 255 ) {
r = ( r * 255 ) / m ;
g = ( g * 255 ) / m ;
b = ( b * 255 ) / m ;
} else {
r = ( r * lut ) / luma ;
g = ( g * lut ) / luma ;
b = ( b * lut ) / luma ;
}
dst [ x + histeq - > rgba_map [ R ] ] = r ;
dst [ x + histeq - > rgba_map [ G ] ] = g ;
dst [ x + histeq - > rgba_map [ B ] ] = b ;
2013-04-17 00:21:17 +00:00
oluma = av_clip_uint8 ( ( 55 * r + 182 * g + 19 * b ) > > 8 ) ;
2012-10-20 05:45:51 +00:00
histeq - > out_histogram [ oluma ] + + ;
}
}
src + = inpic - > linesize [ 0 ] ;
dst + = outpic - > linesize [ 0 ] ;
}
# ifdef DEBUG
for ( x = 0 ; x < 256 ; x + + )
2015-08-18 00:45:35 +00:00
ff_dlog ( ctx , " out[%d]: %u \n " , x , histeq - > out_histogram [ x ] ) ;
2012-10-20 05:45:51 +00:00
# endif
2013-03-10 00:30:30 +00:00
av_frame_free ( & inpic ) ;
2012-10-20 05:45:51 +00:00
return ff_filter_frame ( outlink , outpic ) ;
}
static const AVFilterPad histeq_inputs [ ] = {
{
2013-09-07 12:13:50 +00:00
. name = " default " ,
. type = AVMEDIA_TYPE_VIDEO ,
. config_props = config_input ,
. filter_frame = filter_frame ,
2012-10-20 05:45:51 +00:00
} ,
} ;
static const AVFilterPad histeq_outputs [ ] = {
{
2013-09-07 12:13:50 +00:00
. name = " default " ,
. type = AVMEDIA_TYPE_VIDEO ,
2012-10-20 05:45:51 +00:00
} ,
} ;
2021-04-19 16:33:56 +00:00
const AVFilter ff_vf_histeq = {
2012-10-20 05:45:51 +00:00
. name = " histeq " ,
. description = NULL_IF_CONFIG_SMALL ( " Apply global color histogram equalization. " ) ,
. priv_size = sizeof ( HisteqContext ) ,
. init = init ,
2021-08-12 11:05:31 +00:00
FILTER_INPUTS ( histeq_inputs ) ,
FILTER_OUTPUTS ( histeq_outputs ) ,
2021-09-27 19:47:47 +00:00
FILTER_PIXFMTS_ARRAY ( pix_fmts ) ,
2012-10-20 05:45:51 +00:00
. priv_class = & histeq_class ,
2013-05-08 23:04:41 +00:00
. flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC ,
2012-10-20 05:45:51 +00:00
} ;