Sometimes my DVD plays choppy on computers and DVD players. Why?

Media quality and/or burn speed sound like the culprit here.

If you are burning a 'master' disc that will be played in a variety of players, you should burn it at the slowest speed your drive will support, this is especially true if you are using cheap/offbrand blank media.

Other things to check: make sure before you burn the disc that it is free of dust and fingerprints.

Also, try to use DVD-R discs instead of DVD+R. There is mostly no difference, but older DVD players tend to like DVD-R over DVD+R.

Try better quality DVD blanks, Verbatim Data Life Plus has been good for me.

If that and burning slower doesn't work well enough, try using a portable DVD burner to burn the disk, these are like $25 and plug into a USB port.

Don't max out the video bit rate on the DVD, that can cause some players to choke on it. Keep it at 8 or lower and see if the problem goes away.

Good point

I'll second the tips on keeping down the data rate you're burning to disk, sometimes the lower burn speed can help. I always use DVD-R, but I have come across systems that don't like those disks, but will work with a DVD+R so it may help to have both versions just in case. I would also suggest a USB flash drive with an mp4 file on it, as many newer players can also use these files as well.