The VOB files are likely the source of your difficulties. Converting the files to the DV-AVI format using a program like MPEG-Streamclip will likely resolve your issues.
The very first project I ever worked on in Premiere Elements had footage from a MiniDV camcorder and a Canon DVD camcorder. The files from the DVD camcorder were very difficult to work with in Premiere Elements until I converted them to DV-AVI's. After that, editing, burning, and quality were all very good.
If you are interested in MPEG Streamclip, you can get it here:
If one is using any DVD camera as a source, then there is the first MPEG-2 compression to consider. Then, if they wish to burn a DVD, there is a second DVD MPEG-2 compression. This is not the ideal source for source footage.
One should consider only doing cuts, and using an NLE that offers "smart Rendering," which is really Transcoding. That is as good as it will get. DVD cameras are meant for viewing with direct connections to a TV and not for any editing.
Thanks for the reply Hunt (aka Wine Snob) ... the multiple MPEG-2 compression observation certainly makes sense. I'm guessing this is similar to the issue of working with JPEG images in Photoshop ... you want to make sure you don't save edits as JPEG which would continually degrade the image.
I can't help it ... I watch the original (source) DVD on my TV and the video looks great. I just want to take that original DC50 DVD, add a nice menu, and burn it to a DVD I can hand out to friends. I actually want to do more than this but I'd be satisfied with accomplishing a "clean" copy for now.
Paul787 mentioned the VOB files being the likely source of the degraded quality. I'd be willing to believe this since I don't have a problem with the MOV files from my Canon 5D Mark II SLR camera. I'd actually reword this to note that my specific problem is with PE and the VOB files from a Canon DC50 <whew>. Last night I worked with Nerovision and was able to create my 4GB video in just a couple of hours ... trimmed a little footage, added a nice menu ... and burned a DVD. The DVD created by Nerovision looks great ... just like the original/source DVD's from the DC50. Why is it that the goofy little nerovision works for me and the feature-rich application from a company focused on media does not? And thanks too for Paul's response.
Here's a little observation I left out only because I think it complicates the discussion ... it's interesting though. The Canon DC50 is advertised as having "true widescreen HR" capabilities ... as opposed to other recorders that do some kind of mojo to produce a 16:9 video. I'm not real clear on this but I do know that when you open the VOB with Premiere Elements it treats it as a 4:3 video. The football players get taller and thinner ... and you have the black bars on the side. I have to "interpret the footage" and tell Premiere it's 16:9. Nerovision on the other hand reads in the VOB file and displays the video correctly as 16:9 footage. One would think this is where the problem is with PE8 interpreting the VOB file incorrectly but here's where something completely weird happens ... I had this brilliant thought of simply exporting the footage from Nerovision to something like an AVI file ... my hope was to use PE8 to edit and work with the AVI files. This would whack out my workflow a little bit but I'd get to spend most of my time working with the video in PE8. So I exported the video from Nerovision as an AVI file. I then went to view the AVI file with something like windows media player just to check it ... holy cow, it was in a 4:3 format. I went back to Nerovision and specifically set it to export as 16:9 ... nope, it still plays as a 4:3 ... what the hey. By this time I've been reduced to babbling in front of my computer ... fortunately my wife pulls me away and suggests a good night sleep.
I really wish I could accomplish this quality with PE8 ... I like the PE8 application much better than Nerovision. If there's another camcorder that works better with PE then I'd consider purchasing a new camcorder. Sometimes the effort to "fix" a solution is more costly than "purchasing" a solution. I'll have to admit though ... I've learned a lot with things not working smoothly.
The JPEG analogy is right spot on. JPEG re-compression will degrade the image, just as multiple MPEG compression will.
There are some editing programs, that will do "smart Rendering." What this means is that for areas of MPEG-2 footage, that is not changed, no re-Transcoding will be done. This keeps the source footage in the original MPEG-2 (the AV that is inside the VOB container), and just copies it over. Now, where there will be degradation is where the footage was changed. This could be a Title, or PiP, or other editing. There, the material will need to be re-Transcoded. In these cases, the degradation will take place, but just for a smaller segment of the AV file.
I do not have a list of NLE's that can do "smart Rendering," but if you Google for that term, you'll probably see quite a few. Some will be commercial, and some will be freeware. NeroVision might well do smart Rendering. I just do not know.
As for what is inside a VOB, this ARTICLE will give you some background.
Now, PrE (and PrPro) have a different workflow. They are designed to edit DV-AVI Type II files, HDV and AVCHD (also MPEG, but HD, so you do not see the degradation anywhere near as much). What happens with an MPEG file is that to edit at a frame level, the GOP (Group of Pictures) structure is Rendered, so that you have every Frame of the AV file. This ARTICLE will explain GOP a bit more. With an NLE that employees smart Rendering, any GOP that is not altered in any way is just retained, as is, so no re-Transcoding.
Hope that this explains things a bit more.