Saving DVD to file for the first time

[mkvbob]

My objective is to save the movie content from a VIDEO_TS folder to an mp4 with the end result being as lossless as possible.

1. If I have no need for DVD structure elements like menus and chapters, can I ignore the nav-data and all other stuff except for the audio and video streams in the main VOB files? Or is the nav-data still useful for extracting the main movie content properly?

2. Using

ffmpeg -fflags +genpts -i "concat:VTS_01_1|VTS_01_2" -c copy out.mp4

I got a seemingly lossless result with unchanged picture quality and audio sync, but one thing I noticed when using MPlayer to advance through the video frame-by-frame is that in contrast to the MP4, the original VOB required 2 steps for the frame to change. The video is interlaced, so maybe this has to do with how the VOB/MP4 containers actually define what a frame is?

3. I read about deinterlacing and that there are some advanced algorithms that produce the best quality, but also require the most processing power. What are these and how would I go about using them with ffmpeg to deinterlace my video? Perhaps I would have to use some other tool in order to use them.

4. Are there any deinterlacing methods that don't require the video to be re-encoded, and if so, which ones are the best?