Wrote the FindPSI test which revealed a bug regarding creation of a PMT using comcast gots. This was fixed by writing Payload function and
extracting payload of PMT packet before giving to psi.NewPMT.
We have only ever used this function to find PSI so it makes sense to make it exclusive for this. It now also returns the streams found in the PMT. So that
we can actually retrieve the PIDs of the media and their types.
This func will further segment an MTS segment to each series of packets that
correspond to a given key and val of meta. Testing for this func has also been
written.
Added H264ID and H265ID consts and added logic to select this const for use in encoder based on mediaType param in NewEncoder. Also now
declaring PMT in NewEncoder so that we can set streamID correctly based on mediaType.
Completed test TestFindPid to validate function of FindPid func in mpegts.go. Through this
process, it was found that there was a bug in this func, whereby the returned packet was
not complete due to indexing issues. The bug is fixed and the test passes.