I assume by DD you mean DD 5.1 and not DD 2.0 - DVD recorders typically do record in Dolby Digital (it is the standard audio format for a DVD per the DVD Forum, although PCM is also supported), but without a digital audio input or a six-channel analog audio input to carry a multichannel signal to the recorder there is no way to do more than stereo (be it Dolby Digital or PCM) and you won't find either of those on a consumer grade set-top DVD recorder. You might be able to use a combination of sound card, PC software, and DVD burner drive to produce a DD 5.1 disc, but I'm not sure how many problems you might run into even then.