Changes included adding support for variable InputCodec that may be set via netreceiver/vidgrind to set to H264/MJPEG. Also setting revid's lexTo
function to mjpeg.Lex in the case of an MJPEG InputCodec. Added options parameter to mts.NewEncoder function so that we can change options of the
encoder, namely whether it bases PSI interval on NAL type, or number of frames - in the case of MJPEG we based PSI interval on number of frames.
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.
Wrote a test to check mts encoding of video to validate packet creation etc. Test is failing because how I did mts
encoding is interesting, thinking about changing.
Saxon