Please help with my DVD problem

Hey all

I have been searching online for a while but cannot find an answer.
I am having trouble with DVD movies burnt on the machine. So far I have had one sucess but failures using the same method. This is using a variety of video files from my skating days
When watching the movies on a dvd player / PC they freeze, so I beleive this is a transcribing problem.

right So i have used to different brands, a variety of speeds and two different wrting programs but still get no joy and Im using windows 7

The file I had sucess with was .mkv and I used AVI2DVD to make the VOB files. I then used NTI to burn, not certain but I believe it was 4x.

The second file was a mp4, converted using AVI2DVD with chapters and burnt using NTI and Nero. Both freeze at 0:50:01 on the DVD player and using 3 differnt video programs on the pc, burnt using 4x then 2x. Burns complete sucessfully but freeze at the same point. The .VOB files play on the PC with no issue.

The third file was an .AVI. I just used nero to make a video DVD with no chapters, same results, when burnts at 4x speed the disc will freeze at 0:51:16, but when burnt at 2X speed it will freeze at 0:48:21, i didnt use the same image for the burn, I did two seperate projects

Intermittantly the disc will complete sucessfully using NTI but will stil be blank.

i dont think that the laser head is faulty as the freeze times are different. I dont think its the media as I have used two types. Im certain that it is a transcribing / encoding issue but as the .vob files will play on the machine im confused.

Has anyone got suggestions

Warm regards