MP4 HEVC to MP4 HEVC in FCP

Just wondering if it is possible to put some titles and text on a video which is shot in MP4 HEVC in Final cut pro and then export it using the same format. As per my understanding, the render is done in Apple Pro Res which is then exported to desired container/codec later. 

For egs, in lumafusion, this is straightforward, you import HEVC and you can export HEVC.

From FCP you can only export to HEVC using an Apple Devices preset, which has specific frame resolutions. You can then change the extension to .mp4. If you need a different frame resolution you could use Compressor or a Compressor setting in FCP. 

Hi Tom, I was aware of this bit however, my question was related to editing the MP4 HEVC file on FCP. Why is the file first converted to Apple pro Res unlike other software where you can make the changes on the source file without changing the format. So eventually. MP4 HEVC is imported and MP4 HEVC is exported. Is this possible in FCP without converting it to PRORES first ?

Why do you think it's converted? It isn't. It might be optimized if you have that option selected on import. That's primarily for playback purposes, but no conversion takes place. The optimized files would also be used depending on your export options. 

What you're seeing when you create a new Project is what the Timeline playback render files will be encoded as, IF you ever chose to render the Timeline for playback.