You should refer to the GPL license to do so, and notably its 3rd paragraph. How do I redistribute a piece of VideoLAN ? IF i want to distribute the the vlc with my application then. VLC now is the alternate software to Perian and most users have installed. VLC have open source code if any development want to use it,but still i don’t use the source code just the builded application from them. IF the user don’t want to download to extend mt application,then my application work perfect as is without conversion. IF NOT then i just prompt the user to download one of this applications or (Builded library) to provide the convert. My application only provide the convert method IF the user have the mentioned software installed. You can use the software in the way you want (within the boundary of law), for personal, educational, research, military, governmental, professional purpose or any other way. What are the usage restrictions for VideoLAN software? This is what i get from the official page of vlc legal page So long as your program only calls or executes the existing GPL-covered tool, you are not bound by the GPL with regard to your application and code. This is exactly what I was referring to above. Why do we care about this? Because we want to make sure the users clearly understand the free status of the GPL-covered software in the collection. The issue is simply one of form: how you describe what you are doing. If the two programs remain well separated, like the compiler and the kernel, or like an editor and a shell, then you can treat them as two separate programsbut you have to do it properly. The substantive part is this: if the two programs are combined so that they become effectively two parts of one program, then you can’t treat them as two separate programs. The difference between this and incorporating the GPL-covered software is partly a matter of substance and partly form. To do this validly, you must make sure that the free and non-free programs communicate at arms length, that they are not combined in a way that would make them effectively a single program. However, in many cases you can distribute the GPL-covered software alongside your proprietary system. To quote that section and add further validation to what I have found to be legally true:

Ffmpeg copy segment of mp3