If you have the DVD's on hand, you should be able to pop them Into your computer and use software to convert It Into the appropriate smartphone format. I can vouch for Freemake Video Convertor http
/www.freemake.com/free_video_converter/ It's converts multiple formats Into a wide range of video formats, It can even convert DVD or video links from YouTube and other video streaming sites.
If you could go In a bit more detail as to what DVD you have to convert and which phone you wish to convert It to, then I could give you more detail Into how to proceed with a conversion.
For editing the video your best solution would be to download a video editing software such as Sony Vegas or Adobe After Effects. These professional software will allow you to edit videos from an MP4 format or other various formats to edit the sound, picture quality and to add various other edits or effects to your video.
Once again If you could post more detail as to what computer you have, what software you have if you have any for video editing, what your skill level Is with editing videos and what your budget Is if you are willing to purchase software to do so.
I hope the information I have provided will help you In some way or another, If you have any questions feel free to ask.
Thanks
Matt