ffprobe: increase precision for the shown float values

ffprobe.c

@@ -123,7 +123,7 @@ static char *value_string(char *buf, int buf_size, struct unit_value uv)
         }
 
         if (show_float || (use_value_prefix && vald != (long long int)vald))
-            l = snprintf(buf, buf_size, "%.3f", vald);
+            l = snprintf(buf, buf_size, "%f", vald);
         else
             l = snprintf(buf, buf_size, "%lld", (long long int)vald);
         snprintf(buf+l, buf_size-l, "%s%s%s", *prefix_string || show_value_unit ? " " : "",