Ok, so I'm sure that there are multiple ways to achieve the first part of what I'll describe, but authoring a DVD with LPCM audio is a little more tricky (although I have a very easy solution, so "stay tuned," LOL)
So, assuming that the LPCM audio you captured is 48kHz and 16bit (if it was 44.1kHz for some reason, you will need to convert it to make it DVD-compliant) you need to demux it from the AVI file that you have. There are multiple ways to do this and I assume that you know how to do this part. For some tricky files that don't want to demux easily (especially if they have LPCM audio) the easiest way is to open the video file in Audacity and import the audio. Granted, you will have to re-encode to another LPCM (WAV extension) but since it's lossless, technically, it should be a 1:1 copy.
Anyway, the important part here is transcoding the video from MagicYUV to a DVD-friendly codec.
Open VirtualDub and drop your AVI file onto it. Once it's opened up, click on the "Audio" menu and select the "No Audio" option, as you want to JUST encode the VIDEO in this step. Under the "Video" menu, leave the option "Full Processing Mode" checked and select the "Compression" option. Then select "ffdshow Video Codec" and click on the "configure" box to the right. A window will pop-up with various options. Under the "Encoder" pull-down menu the option "MPEG-4" will probably be check by default. Change this to MPEG-2. The "FOURCC" option should automatically change from "XVID" to "MPEG" Next, since the total cutoff bitrate for a DVD-complaint stream is ~9800kbps and you are including LPCM audio (which is 1536kbps) and you need to account for overhead, I would suggest selecting a bitrate ~7500-8000kbps (with the "Mode" option set to "Single Pass - average" which is the default option there)
Since you are encoding interlaced video, under the "Other options" rectangular box on bottom, select the "Interlaced encoding" option and "Top field first" (unless, for some reason, you captured bottom field first, but I doubt that) Once this is done, select OK and then encode the video. Using avidemux, remux the AVI file into an MPEG file WITHOUT the audio stream.
Now, you should have to files that are ready for you final DVD9:
- a DVD-compliant MPEG-video stream
- a 48kHz 16bit WAV file (LPCM audio)
The next part is what I have found to be tricky and had to do a lot of research to solve the problem. It's pretty funny, because even though LPCM is DVD-compliant, there are practically no DVD-authoring programs on the PC (Windows platform) that accept LPCM/WAV files and usually only give you the option to use MP2 audio or, the most common option, AC3. In most cases, this doesn't matter, but there are those times... It's happened to me and maybe it can help you now...
WARNING: I am NOT affiliated with the program that I am recommending, nor am I getting ANY kind of compensation for suggesting it. I am ONLY suggesting a program that has worked for me, that I found out about from some other forum (believe it was doom9) and want to share the info. The app is a paid app, BUT it offers a FULLY functional trial version that works for 30 days. (I use Sandboxie and just re-install the trial in a new sandbox when I need to use the program)
So, the program that I am talking about is from Womble and it's called MPEG Wizard DVD. The trial can be found here:
http://www.womble.com/download/
When you install and run the app, you want to drop the audio and video streams onto the timeline. (There are various options for building chapters, menus, etc but I'm covering only the very basic part here. If you need more help figuring out the other options, feel free to PM me) Now, the option to author a DVD with the LPCM audio is a little tricky to find and most people that use the app for the first time make the mistake of selecting the "Tools" menu and then selecting "MPEG multiplexer," thinking that this will be the correct course, but that will ONLY give you options for MP2 audio (!)
The way to make it work is to import the audio/video stream on to timeline and in the "Export" window, select the option that says "Template." Under the "Audio Parameters" options there will be an option that says "Linear PCM" which you need to check. Then finish authoring the disc and enjoy.
Again, if you need more help, PM me