Although CDs and DVDs look similar in shape and are used to store data, that ends the similarities between the different discs. The players are even different because a DVD player needs to possess the ability to read a DVD and a CD player needs the ability to read a CD. A few main differences stick out between the players.
What They Can Play
Most DVD players possess the ability to play any format of CD. This allows you use only one device for both your audio and video needs (saving you money in the process). However, CD players do not play DVDs. This is typically because the the laser in the CD player can not read the data on a DVD. In order to fit more information into the DVD, the data is pressed in more tightly. Because the information is more spread out on a CD, a DVD player has no problem reading the data.
DVD players have a video output. This allows you to connect the DVD player to a television and play the audio and video content. Oftentimes a DVD player has multiple video outputs so you can use the best available connection between the DVD player and your television. CD players do not have the video output--only audio. This is another reason why CD players cannot play a DVD.
There are basically two different kinds of CD formats used in CD players: CD-R and CD-RW. The only difference between a the two is a CD-RW can be recorded over. However, there are more than a half-dozen different DVD formats as of 2010, including DVD-R, DVD+R, DVD+RW, DVD-RW and DVD-RAM. Although some older DVD players to not accept all the different formats, most new DVD players are made to play all the DVD formats in addition to the two different CD formats.
Most CD burners built into a computer can burn a CD known as a video CD. This is like a DVD; however, the resolution is not as good and the amount of footage you can put onto a video CD is significantly less. Although the quality is far below that of a DVD, using a video CD is a cost-effective method if you only need to burn a few minutes of information and don't want to use the more expensive DVDs. Because most CD players do not have the video output built in, the only way you can watch a video CD is through a DVD player.
The laser in a DVD player is equipped to read dual-layer DVDs. This means two layers of information are placed on top of one another in order to fit more data onto the single disc. Although a small amount of resolution and audio quality is lost during the process, most Hollywood movies are produced using this format. If you have ever purchased a DVD movie and it is on two different discs, it is because the company producing the DVD did not want to lose any audio or video quality by placing everything onto a dual-layer DVD. CD players are not built to read the multiple layers of information built in to a disc.