Why do I need it? :
X3 is tempermental with many different codec’s. Certain codec’s combined together can lead to problems ranging from overall performance issues (cutting it in half or more) to stability issues in this game. The problem is magnified because there is also no way in Windows to see which codec’s are actually used by X3 and there is no way to adjust them (this is not referencing the audio codec encoders which can be adjusted with a Windows GUI). So to rule out this common problem that X3 has with the multitude of different codec’s, the DShow Viewer tool was made to see what codec’s X3 is using and how to straighten these problems out. This tool helps you to make sure that X3 uses the default Microsoft DirectShow codec’s and filters. These default codec’s are on everyone’s computer, and is what X3 uses on a new Windows install before additional codec’s are installed by various means. It is a good idea to rule out codec’s for crashes, sound looping, garbled sound and general performance.
I didn't find the right solution from the Internet.