MPEG jumps

[RobDov]

I have converted my MSP8 file to MPEG at:
MPEG files
24 bits, 720 x 480, 29.97 fps
Lower Field First
(DVD-NTSC), 16:9
Video data rate: 6000 kbps
Audio data rate: 224 kbps
Compression quality: 70

Trying the file made from the hard drive the audio is jumpy in places and causes the video to slow down. Is this a playing software issue? WinMedia copes better than Power DVD.
Will this play okay once on DVD if it is the software?

I have tried to understand about altering the bitrate and onepass against 2pass and VBR and CBR but I haven't found anything which is straight forward and clear.

Many thanks in anticipation of your advice.