DTS is just another flavor of audio for DVDs--that is, video DVDs. Like Dolby Digital (and MP3s), it uses lossy compression (i.e., low resolution). These days, I think most AV receivers can read both DTS and DD soundtracks, so you're covered.
DVD-A and SACD are high-resolution audio-only formats. Completely different beasts, for which you need a DVD player that can read either, or both.
DVD-A and SACD are high-resolution audio-only formats. Completely different beasts, for which you need a DVD player that can read either, or both.