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mlt/src/modules/core/filter_brightness.c

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/*
* filter_brightness.c -- gamma filter
* Copyright (C) 2003-2004 Ushodaya Enterprises Limited
* Author: Charles Yates <charles.yates@pandora.be>
*
* This library 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.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "filter_brightness.h"
#include <framework/mlt_frame.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/** Do it :-).
*/
static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
{
// Get the image
int error = mlt_frame_get_image( this, image, format, width, height, 1 );
// Only process if we have no error and a valid colour space
if ( error == 0 && *format == mlt_image_yuv422 )
{
// Get the brightness level
double level = mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "brightness" );
// Only process if level is something other than 1
if ( level != 1.0 )
{
uint8_t *p = *image;
uint8_t *q = *image + *width * *height * 2;
int32_t x = 0;
int32_t m = level * ( 1 << 16 );
while ( p != q )
{
x = ( *p * m ) >> 16;
*p = x < 16 ? 16 : x > 235 ? 235 : x;
p += 2;
}
}
}
return error;
}
/** Filter processing.
*/
static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
{
// Get the starting brightness level
double level = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "start" ) );
// If there is an end adjust gain to the range
if ( mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "end" ) != NULL )
{
// Determine the time position of this frame in the transition duration
mlt_position in = mlt_filter_get_in( this );
mlt_position out = mlt_filter_get_out( this );
mlt_position time = mlt_frame_get_position( frame );
double position = ( double )( time - in ) / ( double )( out - in + 1 );
double end = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "end" ) );
level += ( end - level ) * position;
}
// Push the frame filter
mlt_properties_set_double( MLT_FRAME_PROPERTIES( frame ), "brightness", level );
mlt_frame_push_get_image( frame, filter_get_image );
return frame;
}
/** Constructor for the filter.
*/
mlt_filter filter_brightness_init( char *arg )
{
mlt_filter this = mlt_filter_new( );
if ( this != NULL )
{
this->process = filter_process;
mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "start", arg == NULL ? "1" : arg );
}
return this;
}