You need to keep your overall bit-rate around 9 Mbps or below. I always keep it between 8 to about 8.7 Mbps at maximum (or less) 2 pass VBR.

VBR (variable bit rate) is easier for a player to read. Puts less stress on the player. And set-top players are often not designed well & can't play bit rates higher than 9 very well, resulting in freeze frames, dropped frames, skipping, etc.

By overall bit rate I meant video & audio combined. PCM audio takes up 1.6 Mbps. Whereas, Dolby Digital (ac3) takes up to about max 320 kbps (0.32 Mbps) in stereo mode or higher in surround mode. So my suggestion is to ensure your audio is in dolby digital (ac3) format. It uses a heap less bit rate & is comparable to high quality mp3 but perhaps a little better.

Keep your video VBR (preferably 2 pass for better quality even if it takes twice as long) & 8 Mbps or below. I'm not sure what options are on the new Nero so I don't know if those options are available. They are for the mac Roxio Toast. Well I'm not sure about 2 pass but the other options are there. Also keep your Motion estimation quite high ... around the 8 Mbps if it's a fast action video (less if it's a slow type video like a soap.) Average bit rate depends on length of video & dvd format disk (4.7 or 8.5 GB disk.) But if you were to convert at 8 Mbps for video & PCM for audio, then that would equal 9.6 Mbps & many players will struggle to play it smoothly as suggested at the beginning.

Sorry if my description is vague. I normally convert full PAL video not convert up from the VCD size to dvd. So perhaps I'm not the best person to help due to my lack of such experience. I've only occasionally done that such as for rare video concerts/clips unavailable on dvd or VHS tape. Also, I'm a mac person for video work. Even my vid & audio training were both totally on macs. lol