Yup you need the OMB and the DTI.
As for suppliers, the OMB will provide you with authorized dealers here in the Philippines where you are going to source your videos.
Actually a few years back i inquired on starting a business like this but then i decided not to go with it.
I also did the same. Did not push thru due to the registration fees and high taxes plus competing with piracy. I find this not that profitable anymore unlike the VHS/Beta days.