Avidemux 8)
add some text titles in each video,
@lahratla
Assuming its "Watermarking" you want. Mentioned "Avidemux" (its free) will do that for you. But you still need to re-encode.
Check under Filters>Miscellaneous after loading the video. Increase the "Video Bitrate" slightly to keep the quality.
OR
Check out "mkvtoolnix", it has better options. And MKV container can handle custom menus or watever you want.
You can't do this properly without a little reading. Check out sites like "doom9" or "Videohelp". Hope this helps.