Quality problem?

[stavros47]

I have just finished my first DVD-r backup(shrek) using:
Smart ripper
DVD2AVI
Tmpgenc
IFOedit and nero
When I play back my new DVD-r on action scenes and fast moving scenes the picture becomes distorted and loose quality for a brief time then it seems to rectify itself.
Has anyone seen this problem before or have a possible solution?

[Excavator]

Here are two possiblities, both in your TMPEGenc settings...I'm no expert by far so there is a good chance I'm way off.
The first thing I'd look at is the GOP structure. This from a guide I found:

1
I-pictures are compressed independently (similar to JPEG images). This means they're ideal when the image changes too much, but take up a lot of bits. So if you use too many I-pictures, you will need an overall higher bitrate to keep the quality up. If you're using very short GOPs (under 6 frames), you may increase this value and effectively have several sequences in each GOP (see note at the end of this section). Generally, though, stick with 1.
--
4 (use a value between 1 and 7)
P-pictures are based on previous I and P-pictures. This means they can re-use existing parts of the image and therefore take up much less bits than I-pictures. Using P-pictures lets you keep an overall lower bitrate, and use the excess to improve the I-pictures. However, P-pictures may decrease the image quality if there are too many changes from the previous frame. The option to detect scene change (below) will automatically insert an I-picture if it detects a big change between two frames.
--
1 (use a value between 0 and 3).
B-pictures are based on past and future I and P-pictures. They provide the best compression but, as with P-pictures, have problems when the image changes too much. Also, bear in mind that B-pictures cannot be based on other B-pictures, so don't use too many in a row or the image quality may suffer, especially if there are any cuts or sudden changes. If you're using a high average bitrate (above 6500), you can use I and P-pictures only.
15 (for PAL) or 18 (for NTSC).
--
These are the standard DVD limits. This option is not present in older versions of TMPGEnc. If you're using one of those versions, you will need to control the number of frames using only the three previous settings. If a GOP has more frames than the standard allows, authoring programs will usually reject the file.

And I thought this looked even more likely. It's the Field Order setting under the Advanced tab:

Bottom (for DV) or Top (for analog)
This is the source of many problems, since some systems don't say what field order they use, and some pseudo-DV systems actually capture in analog mode. The field order is set by the capture hardware, not by the editing program, so you can't change it in software without re-compressing all the footage. All you can do is make sure you set this parameter right, so that TMPGEnc knows how to encode the file. If you notice your MPEG video flickers whenever there is fast movement (this will only be visible on video monitors and TV sets, not on the PC screen), then the most likely cause is a wrong field order setting.

[thingimijig]

just doing shrek myself.
after ripping just the film and audio it is just short of 4gb therefore you should have perfect quality without re-encoding.

if you decided to keep all the menus i can only guess that you may of re-encoded far short of the maximum disc space.

[stavros47]

Thanks Thingimijig and Excavator for your assistance.
As for the GOB structure I am using
I = 1
p = 4
B = 2
I understand this is the standard for a Pal DVD?
I thing my problem is just Im encoding at a to low bitrate, because when I went to encode it gave me a message saying the bitrate needed to be reduced to 4072 so it would fit on a DVD but after using IFOedit I have looked at my VIDEO_TS file and it is only 1.5GB! So Im going to experiment with a higher bitrate.
Thanks again