Antiflicker filter initial version

Signed-off-by: Laurent Aimar <fenrir@videolan.org>

modules/video_filter/Modules.am

@@ -58,6 +58,7 @@ SOURCES_swscale = swscale.c ../codec/avcodec/chroma.c
 SOURCES_scene = scene.c
 SOURCES_sepia = sepia.c
 SOURCES_yuvp = yuvp.c
+SOURCES_antiflicker = antiflicker.c
 SOURCES_atmo = atmo/atmo.cpp \
 	atmo/AtmoDefs.h \
 	atmo/AtmoCalculations.cpp atmo/AtmoCalculations.h \
@@ -127,4 +128,5 @@ libvlc_LTLIBRARIES += \
 	libwall_plugin.la \
 	libwave_plugin.la \
 	libgradfun_plugin.la \
-	libyuvp_plugin.la
+	libyuvp_plugin.la \
+	libantiflicker_plugin.la

modules/video_filter/antiflicker.c

+/*****************************************************************************
+ * antiflicker.c : antiflicker video effect plugin for vlc
+ *****************************************************************************
+ * Copyright (C) 2000-2011 the VideoLAN team
+ * $Id:
+ *
+ * Authors: Dharani Prabhu <dharani.prabhu.s@gmail.com>
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_filter.h>
+#include "filter_picture.h"
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+static int GetLuminanceAvg( picture_t * p_pic );
+static picture_t *Filter( filter_t *, picture_t * );
+static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
+                           vlc_value_t oldval, vlc_value_t newval,
+                           void *p_data );
+
+static int  Create    ( vlc_object_t * );
+static void Destroy   ( vlc_object_t * );
+
+#define WINDOW_TEXT N_("Window size")
+#define WINDOW_LONGTEXT N_("Number of frames (0 to 100)")
+
+#define SFTN_TEXT N_("Softening value")
+#define SFTN_LONGTEXT N_("Number of frames consider for smoothening (0 to 30)")
+
+#define FILTER_PREFIX "antiflicker-"
+
+#define MAX_WINDOW_SZ 100
+#define MAX_SOFTENING_SZ 31
+#define SCENE_CHANGE_THRESHOLD 100
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+vlc_module_begin ()
+    set_description( N_("antiflicker video filter") )
+    set_shortname( N_( "antiflicker" ))
+    set_capability( "video filter2", 0 )
+    set_category( CAT_VIDEO )
+    set_subcategory( SUBCAT_VIDEO_VFILTER )
+
+    add_integer_with_range( FILTER_PREFIX "window-size", 10, 0, MAX_WINDOW_SZ,
+        WINDOW_TEXT, WINDOW_LONGTEXT, false )
+
+    add_integer_with_range( FILTER_PREFIX "softening-size", 10, 0, MAX_SOFTENING_SZ,
+        SFTN_TEXT, SFTN_LONGTEXT, false )
+
+    add_shortcut( "antiflicker" )
+    set_callbacks( Create, Destroy )
+vlc_module_end ()
+
+/*****************************************************************************
+ * filter_sys_t: Distort video output method descriptor
+ *****************************************************************************
+ * This structure is part of the video output thread descriptor.
+ * It describes the Distort specific properties of an output thread.
+ *****************************************************************************/
+struct filter_sys_t
+{
+    int ia_luminance_data[MAX_WINDOW_SZ];
+    vlc_mutex_t lock;
+    int i_window_size;
+    int i_softening;
+    uint8_t *p_old_data;
+};
+
+/*****************************************************************************
+ * Create: allocates Distort video thread output method
+ *****************************************************************************
+ * This function allocates and initializes a Distort vout method.
+ *****************************************************************************/
+static int Create( vlc_object_t *p_this )
+{
+    filter_t *p_filter = (filter_t *)p_this;
+
+    switch( p_filter->fmt_in.video.i_chroma )
+    {
+        CASE_PLANAR_YUV
+            break;
+
+        default:
+             msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
+                      (char*)&(p_filter->fmt_in.video.i_chroma) );
+            return VLC_EGENERIC;
+    }
+
+    /* Allocate structure */
+    p_filter->p_sys = malloc( sizeof( *p_filter->p_sys ) );
+    if( p_filter->p_sys == NULL )
+        return VLC_ENOMEM;
+
+    p_filter->pf_video_filter = Filter;
+
+    /* Initialize the arguments */
+    p_filter->p_sys->i_window_size = var_CreateGetIntegerCommand( p_filter,
+                                               FILTER_PREFIX "window-size" );
+    p_filter->p_sys->i_softening = var_CreateGetIntegerCommand( p_filter,
+                                               FILTER_PREFIX "softening-size" );
+
+    p_filter->p_sys->p_old_data = calloc( p_filter->fmt_in.video.i_width *
+     (p_filter->fmt_in.video.i_height+1),sizeof(*p_filter->p_sys->p_old_data) );
+
+    if( p_filter->p_sys->p_old_data == NULL )
+        return VLC_ENOMEM;
+
+    memset( p_filter->p_sys->ia_luminance_data, 0,
+                    sizeof(p_filter->p_sys->ia_luminance_data) );
+    p_filter->p_sys->ia_luminance_data[p_filter->p_sys->i_window_size - 1] = 256;
+
+    vlc_mutex_init( &p_filter->p_sys->lock );
+    var_AddCallback(p_filter,FILTER_PREFIX "window-size",
+        AntiFlickerCallback, p_filter->p_sys);
+    var_AddCallback(p_filter,FILTER_PREFIX "softening-size",
+        AntiFlickerCallback, p_filter->p_sys);
+
+    return VLC_SUCCESS;
+}
+
+/*****************************************************************************
+ * Destroy: destroy Distort video thread output method
+ *****************************************************************************
+ * Terminate an output method created by DistortCreateOutputMethod
+ *****************************************************************************/
+static void Destroy( vlc_object_t *p_this )
+{
+    filter_t *p_filter = (filter_t *)p_this;
+
+    var_DelCallback(p_filter,FILTER_PREFIX "window-size",
+        AntiFlickerCallback, p_filter->p_sys);
+    var_DelCallback(p_filter,FILTER_PREFIX "softening-size",
+        AntiFlickerCallback, p_filter->p_sys);
+    vlc_mutex_destroy( &p_filter->p_sys->lock );
+    free(p_filter->p_sys->p_old_data);
+    free( p_filter->p_sys );
+}
+
+/*****************************************************************************
+ * GetLuminanceAvg : The funtion returns the luminance average for a picture
+ *****************************************************************************/
+static int GetLuminanceAvg( picture_t *p_pic )
+{
+    uint8_t *p_yplane_out = p_pic->p[Y_PLANE].p_pixels;
+
+    int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
+    int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
+    int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
+
+    if( i_num_lines == 0 || i_num_cols == 0 )
+        return 0;
+
+    unsigned lum_sum = 0;
+    for( int i_line = 0 ; i_line < i_num_lines ; ++i_line )
+    {
+        for( int i_col = 0 ; i_col < i_num_cols; ++i_col )
+        {
+            lum_sum += p_yplane_out[i_line*i_in_pitch+i_col];
+        }
+    }
+    unsigned div = i_num_lines * i_num_cols;
+    return (lum_sum + (div>>1)) / div;
+}
+
+/*****************************************************************************
+ * Filter: adjust the luminance value and renders
+ *****************************************************************************
+ * The function uses moving average of past frames to adjust the luminance
+ * of current frame also applies temporaral smoothening if enabled.
+ *****************************************************************************/
+static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
+{
+    if( !p_pic ) return NULL;
+
+    picture_t *p_outpic = filter_NewPicture( p_filter );
+    if( !p_outpic )
+    {
+        picture_Release( p_pic );
+        return NULL;
+    }
+
+    /****************** Get variables *************************/
+
+    int i_window_size;
+    int i_softening;
+
+    vlc_mutex_lock( &p_filter->p_sys->lock );
+    i_window_size = p_filter->p_sys->i_window_size;
+    i_softening = p_filter->p_sys->i_softening;
+    vlc_mutex_unlock( &p_filter->p_sys->lock );
+
+    uint8_t *p_yplane_in = p_pic->p[Y_PLANE].p_pixels;
+    uint8_t *p_yplane_out = p_outpic->p[Y_PLANE].p_pixels;
+    bool scene_changed = false;
+
+    int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
+    int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
+    int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
+    int i_out_pitch = p_outpic->p[Y_PLANE].i_pitch;
+
+    /******** Get the luminance average for the current picture ********/
+    int lum_avg = GetLuminanceAvg(p_pic);
+
+    /*Identify as scene change if the luminance average deviates
+     more than the threshold value or if it is the first frame*/
+
+    if( abs(lum_avg - p_filter->p_sys->
+        ia_luminance_data[i_window_size - 1]) > SCENE_CHANGE_THRESHOLD
+        || p_filter->p_sys->ia_luminance_data[i_window_size - 1] == 256)
+    {
+        scene_changed = true;
+    }
+
+    if ( scene_changed )
+    {
+        //reset the luminance data
+        for (int i = 0; i < i_window_size; ++i)
+            p_filter->p_sys->ia_luminance_data[i] = lum_avg;
+        plane_CopyPixels( &p_outpic->p[Y_PLANE], &p_pic->p[Y_PLANE] );
+    }
+    else
+    {
+        /******* Compute the adjustment factor using moving average ********/
+        for (int i = 0; i < i_window_size-1 ; ++i)
+            p_filter->p_sys->ia_luminance_data[i] =
+                           p_filter->p_sys->ia_luminance_data[i+1];
+
+        p_filter->p_sys->ia_luminance_data[i_window_size - 1] = lum_avg;
+
+        float scale = 1.0;
+        if (lum_avg > 0)
+        {
+             float filt = 0;
+             for (int i = 0; i < i_window_size; i++)
+                  filt += (float) p_filter->p_sys->ia_luminance_data[i];
+             scale = filt/(i_window_size*lum_avg);
+        }
+
+        /******* Apply the adjustment factor to each pixel on Y_PLANE ********/
+        uint8_t shift = 8;
+        int scale_num = __MIN(scale,255) * ( 1 << shift );
+
+        for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
+        {
+            for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
+            {
+                uint8_t pixel_data = p_yplane_in[i_line*i_in_pitch+i_col];
+                int pixel_val = ( scale_num * pixel_data +
+                       (1<<(shift -1)) ) >> shift;
+                p_yplane_out[i_line*i_out_pitch+i_col] =
+                       (pixel_val>255) ? 255:pixel_val;
+            }
+        }
+    }
+
+    /***************** Copy the UV plane as such *****************************/
+    plane_CopyPixels( &p_outpic->p[U_PLANE], &p_pic->p[U_PLANE] );
+    plane_CopyPixels( &p_outpic->p[V_PLANE], &p_pic->p[V_PLANE] );
+
+    if (scene_changed || i_softening == 0)
+    {
+       return CopyInfoAndRelease( p_outpic, p_pic );
+    }
+
+    /******* Temporal softening phase. Adapted from code by Steven Don ******/
+    uint8_t *p_yplane_out_old = p_filter->p_sys->p_old_data;
+    int i_video_width = p_filter->fmt_in.video.i_width;
+
+    for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
+    {
+        for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
+        {
+            uint8_t pixel_data = p_yplane_out[i_line*i_out_pitch+i_col];
+            uint8_t pixel_old = p_yplane_out_old[i_line*i_video_width+i_col];
+            int diff = abs(pixel_data - pixel_old);
+            if (diff < i_softening)
+            {
+                if (diff > (i_softening >> 1))
+                {
+                    p_yplane_out_old[i_line*i_video_width+i_col] =
+                        ((pixel_data * 2) + pixel_old) /3;
+                }
+            }
+            else
+            {
+                p_yplane_out_old[i_line*i_video_width+i_col] = pixel_data;
+            }
+            p_yplane_out[i_line*i_out_pitch+i_col] =
+                p_yplane_out_old[i_line*i_video_width+i_col];
+        }
+    }
+
+    return CopyInfoAndRelease( p_outpic, p_pic );
+}
+
+/*****************************************************************************
+ * Callback function to set the parameters
+ *****************************************************************************
+ * This function sets the parameters necesscary for the filter
+ *****************************************************************************/
+static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
+                           vlc_value_t oldval, vlc_value_t newval,
+                           void *p_data )
+{
+    VLC_UNUSED(p_this); VLC_UNUSED(oldval);
+    filter_sys_t *p_sys = (filter_sys_t *)p_data;
+
+    vlc_mutex_lock( &p_sys->lock );
+    if( !strcmp( psz_var, FILTER_PREFIX "window-size" ) )
+        p_sys->i_window_size = newval.i_int;
+    else if( !strcmp( psz_var, FILTER_PREFIX "softening-size" ) )
+        p_sys->i_softening = newval.i_int;
+    vlc_mutex_unlock( &p_sys->lock );
+
+    return VLC_SUCCESS;
+}