lavfi/crop: fix help message for the keep_aspect option

libavfilter/vf_crop.c

@@ -102,7 +102,7 @@ static const AVOption crop_options[] = {
     { "w",           "set the width crop area expression",   OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "out_h",       "set the height crop area expression",  OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "h",           "set the height crop area expression",  OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
-    { "keep_aspect", "force packed RGB in input and output", OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
+    { "keep_aspect", "keep aspect ratio",                    OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
     {NULL}
 };