Make movit_mix ignore empty "mix" parameter strings.

Previously, the parameter would have to be entirely unset
(ie., NULL) for the transition progress to be used, which
was suboptimal in some cases.

diff --git a/src/modules/opengl/transition_movit_mix.cpp b/src/modules/opengl/transition_movit_mix.cpp
index 4adc810e9dc7f83cc14ec9b09e138699d16a66f6..3e7ef964879c59faab70fb477508e4bd591428db 100644 (file)
--- a/src/modules/opengl/transition_movit_mix.cpp
+++ b/src/modules/opengl/transition_movit_mix.cpp
@@ -49,7 +49,8 @@ static int get_image( mlt_frame a_frame, uint8_t **image, mlt_image_format *form
        mlt_position position = mlt_transition_get_position( transition, a_frame );
        mlt_position length = mlt_transition_get_length( transition );
        int reverse = mlt_properties_get_int( properties, "reverse" );
-       double mix = mlt_properties_get( properties, "mix" ) ?
+       const char* mix_str = mlt_properties_get( properties, "mix" );
+       double mix = ( mix_str && strlen( mix_str ) > 0 ) ?
                mlt_properties_anim_get_double( properties, "mix", position, length ) :
                mlt_transition_get_progress( transition, a_frame );
        double inverse = 1.0 - mix;