<description>The thresholds of Convolution3d are only here to take care of edges and scene change. You can increase the spatial one (especially the chroma threshold) but stop as soon as you see some blurring around the edges (if you want quality). With the settings proposed you shouldn't have this problem. </description>
<description>It's used especially to speed up a little this filter and to avoid using temporal informations when not needed (scene change, fade, ...) If set to -1 then only spatial work is done (high speed).</description>