Could not find m2t either in the advanced settings
Just out curiosity why do you want m2t.
What custom bitrate do you want to set it at -- and why?
You can output an MTS/M2T file using Export & Share/Device/Computer 1920x1080.
Perhaps unnecessary, but I like to keep my outputs in the same format as the source, the bitrate of which falls between the medium and high-quality presets.
I've also noticed another problem that has arisen in PRE14.
If you go to Custom, Advanced Settings and select H.264 as the output, you get a list of mp4 settings in the Preset list. You can change the Basic Settings to create your own Preset. However, if you then go back to create another preset (or simply use one that appeared in the original list), you can't - the complete list has vanished and you're left with just the preset you created. You have to delete this preset to create another! In older versions, you could create as many user-defined settings as you wanted, and these would appear below the standard list.
Before we go on to another issue, are you satisfied with the answer to your first question? It can get clumsy to try to carry on two conversations in the same thread.
Keeping it the same as the source depends on what you are going to do with the file.
Is it to archive, for the web, dvd, bluray???
Archiving requires a different format then putting it on e.g. Youtube.
Satisfied in so much as I know it's not possible to export as a user-defined m2t file; unsatisfied that this is not an option as in previous versions!
I'm saving as an m2t file both for archiving and for burning to blu-ray.
I'll post the other problem in a new thread.
Best is to burn to Bluray with H.264. Its a far better codec and less artifacten.
For archiving, if one has enough storage, a format with a lossless codec.