dvd vs. sacd

can someone tell me the difference between sacd and dvd please
DVD is video SACD is audio and can be played back in a CD player at regular CD resolution if it is a hybrid disc. SACD can be played back in an SACD player at high resolution and in most cases surround sound.
DVDA is audio and possibly some video and surround. It can be played in an ordinary DVD player at regular DVD resolution or a DVD audio player at higher resolution.
For SACD, you only need a stereo, either 2 channel or 5. DVD audio you really need a video monitor just to play dvd's. Technology is different, as well as sound. For a party, DVD/A is great but, for pure listening, SACD is amazing. Imagine if they took out all video from a dvd and spent that space/time and energy on audio only. That's really the quality difference.
thanks for the help
so if i get this correct they are the same but dvd has video added to it
NO, they are completely different. They use a different form of encoding and decoding. DVD players will play DVDs and CDs. SACD players play SACDs only. CD players play CD only. Some SACD players will play CDs are well. Universal players usually refers to something that plays CD, SACD, DVD, and DVD-A. DVD-A and SACD are higher resolution than CD or DVD, but neither one of the hi-res formats have nearly as much software. Most but not all hi-rez discs have surround sound encoded audio. Some DVD-A discs have companion video to the music.

No, SACD and DVD are not the same. In short, the coding algorithms are different, and they are read by lasers at differing wavelengths.

SACD utilizes Direct Stream Digital (DSD) - 1 bit data samples at a sample rate (freqency) of 2.8224 MHz. It's read by a laser at a wavelength of 650 nanometers (nm).

DVD-A uses PCM (Pulse Code Modulation) like CD, only with larger data samples and a higher sampling rate. CD use 16 bit data words to encode the sample, and samples at anything from about 32 KHz to 48 KHz, if I remember correctly. A sample rate of 44.1 KHz seems to be the most common. CD is read by a 780 nm laser.

DVD-A uses 24 bit data samples, usually sampled at 96 KHz, but can go as high as 196 KHz (maybe higher.) It's read by a 640 nm laser.

In addition, DVD-A uses a lossless compression scheme developed by Meridian. I have read that SACD uses lossless compression as well. I don't believe CD data is compressed.

DVD-V contains video encoded using some variation of MPEG, MPEG-2 I think. It also contains DTS or Dolby Digital 5.1 audio tracks using lossy data compression that throws some of the data away. The DVD box usually tells you about some of this.

These are the basics. There are several good articles on Wikipedia. Google SACD and you will find all kinds of info, both technical and non-technical.

Any Electrical Engineers out there feel free to make corrections where I have made an error.

Bob R.

PS: All's right with the world cause the Yankees just won.
Swampwalker, I thought that all SACD players will play [redbook] CD's...am I mistaken??