Depends on what year you started really. The original DVD burner cost $15k and the blank discs were $50 each but only held 3.95GB of data. The 2nd gen burner dropped to $5k and The first software was painful running under NT 4.0. With specialty discs with a large number of individual assets, it was easy to create so many files in a single folder that the system would slow to a crawl, and eventually crash during the muxing stage. You'd start it up again and watch it fly by the files it had already muxed, and then slow down when it got to the new files. It was a glorious day when Win2k comes out, and the same type of project no longer crashes like it did under NT. WinXP was like a gift from heaven. Then, you'd get some challenging programming requests like make a randomized game attempting to not repeat an item until all items have been displayed once. You get it programmed and begin testing in the plethora of consumer DVD players on the market. You then discover that some of the lower cost players don't acutally have the ability to select a random number. Instead, they have a preset list of random numbers starts over every time the player is restarted making it impossible to play the game as requested. You think browser compatibility is a pain, the DVD player/media combinations were insane.
Then there was MPEG-2 encoding. Early days required specialty hardware boards in your computer to do real-time encoding. These were in the $20k-$50k systems. High end encoders would allow for 2-pass encoding, but that meant playing the VTR for the first pass, rewinding the tape, and then doing the second pass in real-time. A 2 hour movie would take over 4 hours to encode. Then, if there was a problem with the encode (bitrate/buffer spikes/underflows), you'd have to figure out how to solve it and do the encode a second time. If you had the fancy encoder, you could do segment based encodes so you didn't need the full 4 hours. Mid-2000s, software encoding became viable. Now, you could run 2-pass encodes faster than real-time.
Then there were the oddities to deal with like timing was based on a 27MHz clock, so when the software told you there was a problem at time 59265000000, it actually meant 6mins 35secs.
No, I'm not scarred by the experience ;-)
Edit: I didn't actually answer the question. The role was to take the video/stills/subtitle assets and link them together. Every button on a menu screen had to be programmed to go to a specific spot on the disc. The video/audio/subtitles had to be combined to play together, then when finished told where to go, or stop, or loop, etc. Menu elements had to be placed in the correct section of the disc to that the menu/title buttons on the remote behaved correctly. DVDs had a very defined structure. VTS_01.vob VTS_02.vob makes me shudder when I seem them now.