static uint8_t *filter_get_alpha_mask( mlt_frame this )
{
+ uint8_t *alpha = NULL;
+
// Obtain properties of frame
mlt_properties properties = mlt_frame_properties( this );
mlt_properties_set( mlt_frame_properties( shape_frame ), "distort", "true" );
mlt_frame_get_image( shape_frame, &image, &format, ®ion_width, ®ion_height, 0 );
- return mlt_frame_get_alpha_mask( shape_frame );
+ alpha = mlt_frame_get_alpha_mask( shape_frame );
+
+ // Generate from the Y component of the image if no alpha available
+ if ( alpha == NULL )
+ {
+ int size = region_width * region_height;
+ uint8_t *p = mlt_pool_alloc( size );
+ alpha = p;
+ while ( size -- )
+ {
+ *p ++ = *image ++;
+ image ++;
+ }
+ mlt_properties_set_data( mlt_frame_properties( shape_frame ), "alpha", alpha,
+ region_width * region_height, mlt_pool_release, NULL );
+ }
+
+ return alpha;
}
/** Do it :-).