Thank you selur for your answer.
I activated the 'fix delay' option in Hybrid. In fact, individual mp4 files are in synch, and they get out of synch when joined with MP4Box.
My x264 version is r2171, and does not have --stitchable as argument
I may try the mkv way. I did not understand the convert mkv to mp4 with ffmpeg step, and why then convert that mp4 again to mp4 with MP4Box.
Do you think it could be possible to demux the individual mp4 to the elementary x264 and ac3 streams, then add them and join them in a mkv, and again demux the mkv to a joined x264 and a joined ac3, and mux them again with MP4Box?. I may always try.
I'm back
I tried to join directly mp4, and also tried to join the elementary streams, and mmg complains that the video track parameters do not match.
Could this be done in Hybrid?. I mean, can I provide a kind of playlist, as in blu-ray, that points to every chapter movie in the DVD?. This functionality would not be of common use, just in anime and TV series, where a DVD contains several chapters.