Ask by Yusuf Akhsan :

It used to download youtube video results can be easily converted to mp4 so that q can be opened in hp, but in 2011, almost all the videos I downloaded from my yotube can not convert to mp4 orothers, I use format factory.

We have done tests and test on your problems, as this is the problem.

The solution, you can rename the files you have downloaded the video before, remember not to leave one hurufpun, once clean, it is up to rename the original name or new name.