The casing on the picture states it outputs Dolby ProLogic II. This is not the case, a lower grade algorytm is used. This is noticable by the surround signals being the same (mono surround). Also its cut-off frequency for the low pass filter is higher than it should be. This means no bass for the surround speakers. Using analog (aux) input causes an noticable disturbance noise on the speakers. Volume needs to be fairly high to compensate. Its not all bad. It works if you want to use it for the basic mixing for surround and center signals. The output is much alike Dolby ProLogic I, altough no ic's capeble of using Dobly Pro logic are present on the pcb i suspect. If you plan to use it in a silent enviroment on aux, use it with with decently sized surround speakers or use it to upgrade to ProLogic II, it is not sufficient.
Thank you! :)