avfilter/af_crystalizer: improve filter description

doc/filters.texi

@@ -3682,7 +3682,9 @@ Set output gain. Default is 1.
 This filter supports the all above options as @ref{commands}.
 
 @section crystalizer
-Simple algorithm to expand audio dynamic range.
+Simple algorithm for audio noise sharpening.
+
+This filter linearly increases differences betweeen each audio sample.
 
 The filter accepts the following options:
 

libavfilter/af_crystalizer.c

@@ -305,7 +305,7 @@ static const AVFilterPad outputs[] = {
 
 AVFilter ff_af_crystalizer = {
     .name           = "crystalizer",
-    .description    = NULL_IF_CONFIG_SMALL("Simple expand audio dynamic range filter."),
+    .description    = NULL_IF_CONFIG_SMALL("Simple audio noise sharpening filter."),
     .query_formats  = query_formats,
     .priv_size      = sizeof(CrystalizerContext),
     .priv_class     = &crystalizer_class,