+ Correction to uneven chroma samples

git-svn-id: https://mlt.svn.sourceforge.net/svnroot/mlt/trunk/mlt@924 d19143bc-622f-0410-bfdd-b5b2a6649095

diff --git a/src/modules/vmfx/filter_chroma.c b/src/modules/vmfx/filter_chroma.c
index 6d9384c5d05b179b6144c5d6bc3f8e12b531a6e6..d9ab009c0f7f24b34e3e1275f8d86d1d06574c0e 100644 (file)
--- a/src/modules/vmfx/filter_chroma.c
+++ b/src/modules/vmfx/filter_chroma.c
@@ -20,6 +20,7 @@
 
 #include "filter_chroma.h"
 #include <stdlib.h>
+#include <math.h>
 #include <framework/mlt_factory.h>
 #include <framework/mlt_frame.h>
 #include <framework/mlt_producer.h>
@@ -30,9 +31,12 @@ static inline int in_range( uint8_t v, uint8_t c, int var )
        return ( ( int )v >= c - var ) && ( ( int )v <= c + var );
 }
 
-static inline uint8_t alpha_value( uint8_t a, uint8_t *p, uint8_t u, uint8_t v, int var )
+static inline uint8_t alpha_value( uint8_t a, uint8_t *p, uint8_t u, uint8_t v, int var, int odd )
 {
-       return ( in_range( *( p + 1 ), u, var ) && in_range( *( p + 3 ), v, var ) ) ? 0 : a;
+       if ( odd == 0 )
+               return ( in_range( *( p + 1 ), u, var ) && in_range( *( p + 3 ), v, var ) ) ? 0 : a;
+       else
+               return ( in_range( ( *( p + 1 ) + *( p + 5 ) ) / 2, u, var ) && in_range( ( *( p + 3 ) + *( p + 7 ) ) / 2, v, var ) ) ? 0 : a;
 }
 
 /** Get the images and map the chroma to the alpha of the frame.
@@ -58,12 +62,11 @@ static int filter_get_image( mlt_frame frame, uint8_t **image, mlt_image_format
                int size = *width * *height / 2;
                while ( size -- )
                {
-                       *alpha = alpha_value( *alpha, p, u, v, variance );
+                       *alpha = alpha_value( *alpha, p, u, v, variance, 0 );
                        *alpha ++;
-                       p += 2;
-                       *alpha = alpha_value( *alpha, p, v, u, variance );
+                       *alpha = alpha_value( *alpha, p, u, v, variance, 1 );
                        alpha ++;
-                       p += 2;
+                       p += 4;
                }
        }
 
@@ -88,8 +91,8 @@ mlt_filter filter_chroma_init( char *arg )
        mlt_filter this = mlt_filter_new( );
        if ( this != NULL )
        {
-               mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "key", arg == NULL ? "0x00ff00" : arg );
-               mlt_properties_set_double( MLT_FILTER_PROPERTIES( this ), "variance", 0.3 );
+               mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "key", arg == NULL ? "0x0000ff" : arg );
+               mlt_properties_set_double( MLT_FILTER_PROPERTIES( this ), "variance", 0.15 );
                this->process = filter_process;
        }
        return this;

diff --git a/src/modules/vmfx/filter_chroma_hold.c b/src/modules/vmfx/filter_chroma_hold.c
index 2992ceb5102304d8dd3f8d56b16bd568e3b19c66..f3ede3f9757cc287af18313e678a52870f326c32 100644 (file)
--- a/src/modules/vmfx/filter_chroma_hold.c
+++ b/src/modules/vmfx/filter_chroma_hold.c
@@ -30,9 +30,12 @@ static inline int in_range( uint8_t v, uint8_t c, int var )
        return ( ( int )v >= c - var ) && ( ( int )v <= c + var );
 }
 
-static inline uint8_t alpha_value( uint8_t a, uint8_t *p, uint8_t u, uint8_t v, int var )
+static inline uint8_t alpha_value( uint8_t a, uint8_t *p, uint8_t u, uint8_t v, int var, int odd )
 {
-       return ( in_range( *( p + 1 ), u, var ) && in_range( *( p + 3 ), v, var ) ) ? 0 : a;
+       if ( odd == 0 )
+               return ( in_range( *( p + 1 ), u, var ) && in_range( *( p + 3 ), v, var ) ) ? 0 : a;
+       else
+               return ( in_range( ( *( p + 1 ) + *( p + 5 ) ) / 2, u, var ) && in_range( ( *( p + 3 ) + *( p + 7 ) ) / 2, v, var ) ) ? 0 : a;
 }
 
 /** Get the images and map the chroma to the alpha of the frame.
@@ -58,18 +61,13 @@ static int filter_get_image( mlt_frame frame, uint8_t **image, mlt_image_format
                int size = *width * *height / 2;
                while ( size -- )
                {
-                       alpha = alpha_value( 255, p, u, v, variance );
-                       p ++;
+                       alpha = alpha_value( 255, p, u, v, variance, 0 );
                        if ( alpha ) 
-                               *p ++ = 128;
-                       else
-                               p ++;
-                       alpha = alpha_value( 255, p, v, u, variance );
-                       p ++;
+                               *( p + 1 )= 128;
+                       alpha = alpha_value( 255, p, u, v, variance, 1 );
                        if ( alpha ) 
-                               *p ++ = 128;
-                       else
-                               p ++;
+                               *( p + 3 ) = 128;
+                       p += 4;
                }
        }
 
@@ -95,7 +93,7 @@ mlt_filter filter_chroma_hold_init( char *arg )
        if ( this != NULL )
        {
                mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "key", arg == NULL ? "0xc00000" : arg );
-               mlt_properties_set_double( MLT_FILTER_PROPERTIES( this ), "variance", 0.3 );
+               mlt_properties_set_double( MLT_FILTER_PROPERTIES( this ), "variance", 0.15 );
                this->process = filter_process;
        }
        return this;