Authored DVD freezes

I'm looking for a starting point to resolve a DVD authoring problem.

Here's what I'm doing:

1. I have many commercial VHS tapes that I want to convert to DVDs before my VCR dies. For most of them, I play them into a capture device to digitize and then use DVD Styler to convert and burn them to DVD. This works well.
2. Since this is time consuming, I "cheated a bit". For some, I've downloaded a copy from the internet. (I justify that since I have purchased the VHS tape). I then use DVD Styler to convert and burn to a DVD.

My Problem:
For some (but not all) downloaded videos, the resulting DVD will freeze every 3 to 10 minutes. It will only restart if I press "skip" then "play".

In part, here's what I have done:

1. Used MediaInfo to look at the downloaded videos. There is no total commonality but most are MPEG-4 (Base Media) with an AVC video stream.
2. I've converted some of the downloaded videos that originally failed to MPEG-2, then used DVD Flick to convert them to DVD and used CD BurnerXP to burn the DVD.
3. Some DVDs are OK others still freeze. Again, I can't find any commonality in the file format for the failures.

I'm using Memorex DVD-Rs from a 100 spindle. I've used about 80 of these DVDs on the same DVD burner for other projects and not had a single failure.

My default is to use to digitize the original VHS tape but I'd like to find the problem (for my education if nothing else).

Does anyone have a suggestion where I might look for the problem?