Ok ive been using Devede in linux to easily do avi to ISO including the menu's. Then I've just used K3B to burn the ISO. The problem im having is that im not satisfied with the speed of Devede, i cannot seem to get it to use all 4 of my CPU cores (AMD Phenom II X4 940). Im also considering automating this process somewhat by using a script of some sort. So if there are more powerful command line based programs out there im all for them. It doesn't have to be all in one program, but specifically for the encoding part, it needs to be quad core capable, and preferably have "Auto" quality setting to fit a specific volume (4.7GB DVD), or at least show aprox size output BEFORE encoding begins. As far as Menu options, i dont need anything fancy, just a default menu to choose between files on the disk. Im also open to other GUI options, given they fit the criteria.
Edit: Oh ya, this DVD must be suitable for a home DVD player.

Most of these are front ends to ffmpeg / mencoder / transcode / ??? Many of these apps have multi-threading capabilities. However the application might not use those parameters (-threads 0 (auto detect / use all) -threads 2 (for only 2 cores) / with ffmpeg anyway). Also bear in mind that multithreading video encoding can degrade video quality, so there's some debate if you should use it in the first place. Also bear in mind that dual-layer DVDs and burners do exist and contain 8+GB if space is the issue.

Devede is probably the most simple interface. Unless you're just going for a playable dvd, sans menu, sans bells and whistles, you're probably not going to benefit from automation. Unless you're doing it for some sort of security camera system, which wouldn't make much sense since optical discs only hold a couple of hours of content and tape is still much cheaper / more reliable. But there's many front ends to choose from. I tend to be a bit old school myself and just go directly to ffmpeg / mpeg2enc and dvdauthor. Hardly automated by any sense of the word though. Even after much scripting to take some of the burden off my fingers.

Your title is a little confusing. ffmpeg has x11grab capabilities which allows you to record from your X session. Perhaps looking for a GUI for DVD authoring would be a better title. At any rate freshmeat.net has a pretty decent database of linux applications and their intentions / homepages.

Thats the first time i've ever heard that using multithreaded means of encoding reduces quality in ANY way. I've done it lots in windows with no such result. In fact, with my limited understanding of encoding, it makes no sense that using more cores would have ANY effect on quality... where do u get this info from?

I suppose degrade compression would have been a better terminology. Which could be interpreted as quality in terms of useful information over a given file size. Compression of video depends on knowledge of previous frames to determine the cheapest way to render the next frame. When you multi-thread, you don't have that information between threads. You can get better quality per compression when single threading than you do when multi-threading. And if you're using some buggy software multithreaded recompression can yield some unknown results.

Most people are at least on Dual cores now, isnt that still considered multithread? 2 cores and 2 threads... And again... can you give any source to backup this claim?

It's been mentioned on the ffmpeg mailing list. That and there's still a number of codecs that don't yet support multi-threading in ffmpeg. The msmpeg4v2 codec segfaults if I try to multithread it. But suffice to say that better compression equals better quality. Particularly for those formats with fixed and/or low bitrates like that used on DVDs. Maybe not noticeable to most folks, and potentially only noticeable on high bitrate scenes like car chases and the likes. But it should be verifyable(if only in frame grabs). But it also might be software dependent, some commercial applications probably have some communication between threads to minimize / eliminate degredation. Suffice to say that some software doesn't handle multithreading well (yet).

Ok, well if theres no good option for multithreading yet, i guess i may as well stick with Devede for now... thanks for the info.

mpeg2video in ffmpeg is well supported with regards to multi-threading. Which is the codec used on DVDs. You might not get better results using it, but it does work. As long as your result isn't highly compressed, the degredation shouldn't be that noticeable. And if going to an uncompressed format there shouldn't be any degredation (in theory).

I'm just a bit picky since I'm coming from a DSD field recorder and HD camcorder to DVD, I don't want it to look / sound bad, relative to the source. Which with my mostly manual dvdauthor+xml method is controllable. mpeg2enc defaults to -b 7500. But it doesn't include the audio portion. When you mplex the audio in, it appears to degrade the video quality. Being proactive with -b 7000 allows room for the audio without an obvious second degredation. And other quirks I'm starting to notice with compressed audio. mp2enc sounds better to me than .ac3 from ffmpeg. Mostly clarity for things like people talking on megaphones and cymbals. It's just a little frustrating to find better and better ways to render the same end result from the same source. Especially if you've already burned 50 copies for friends.

Tell me about it... in my case i don't mind to sacrifice barely noticeable quality loss for twice the speed (use all 4 cores instead of only 2). I find it frustrating that i paid alot for a quad core and its not being utilized for what i intended.