What's the difference between CDs and DVDs?

Factual Questions
1

Ok. Bring me up to speed here. I’ve got hundreds of audio CDs. I just received my first DVD, of a visual presentation given at a friend’s retirement. Well, he told me it was a DVD. The disc looks just like a CD, to me. I popped it in my computer and it played the presentation as an MPEG, and it’s kinda grainy (I suspect it was copied to the disc from VHS tape). I do not own a DVD player - if I run out and buy one, will this play on the DVD player?

I have heard that DVD players come with different features, or options, allowing you to play different formats. What do I need to buy to view this disc on my TV?

I tried searching the boards for the answers, but was having problems because both CD and DVD are too short to search for…

Thanks in advance for sharing your knowledge…!

2

Non-techie layman’s answer: physically, a DVD and a CD look identical – aside from the label reading “DVD” or “CD,” you won’t be able to tell them apart.

What happens when you insert a DVD into your computer depends on your computer setup. Some will automatically open a DVD player program and begin to play the DVD; others will prompt you for what to do; and still others will just sit there and treat it like any other media.

If a DVD has a movie in muliple formats, you don’t need anything special to view them – it generally means the DVD has multiple copies of the movie, most often pan-and-scan (the traditional 4:3 semi-square screen size) and widescreen (the rectangular 16:9 that everyone is moving towards). You can play the “wrong” version of the movie on your TV, but the image will look slightly distorted.

3

They are both digital storage read by a laser. The main difference is in the materials and the type of laser (and thus drive) that you need to read them. DVDs are much higher density than CDs, and commercial DVDs can hold over 10 times the information on a CD.

Whether or not you can play the DVD your friend gave you in a standalone DVD player is dependent on

  1. The DVD player. Some DVD players (mostly old ones) don’t play nice with burned DVDs
  2. The video encoding format of the DVD (ie, PAL or NTSC). NTSC is used in the US and Japan (I think) and PAL is used in most of Europe and the rest of the world.
  3. Whether it is “DVD standard” video. It’s perfectly possible to put a video file on a DVD that will play on computers, but will not play on a standalone DVD player.

I suggest asking your friend whether it will play in a standalone player, but if (s)he just gave it to you and didn’t give any special instructions, odds are that it will.

For good information on all kinds of CD and DVD video formats, check out VideoHelp.com

4

I’m confused; if it were a DVD, and the OP doesn’t have a DVD-Rom on his computer, it wouldn’t have played at all, would it have? And if it was an MPG, it sounds like someone stuck an MPG on a CD, gave it to the friend, who was confused and thought that because there was a movie on it, it must have been a DVD.

Am I missing something? I mean, I know of enhanced CDs that will play audio in a standard player but also can contain files and images of various sorts to use in a CD-Rom on a computer, but I am not aware of any DVDs that have CD-Rom compatible features.

5

TellMeI’mNotCrazy, you’re not. (How many times do you hear this joke?) Anyway, I accidentally bought the super-duper Sims DVD version and my computer wouldn’t even recognize it as valid data. It just said “Please insert CD into CD drive” or something like that. You need some kind of valid DVD-ROM to play it.

You *can * play a DVD on a PS2, though. I do this occasionally.

6

Thanks for your replies.

Ok - I looked more closely at the disc, and it does indeed say DVD right on it. My computer does have a DVD-Rom.

When I look at the file names on the DVD my computer, they all end .mpg.

iamthewalrus(:3= - I will check out videohelp.com - thanks!

7

If you go shopping for a dvd player, there are some questions you need to ask the salesman.

Make sure it will play DVD, DVD +or- R, VCD, MP3, CD and Enhanced CD.

I own a Philips Home Theater system that won’t play anything but audio CDs and DVD’s. Even CD’s with embedded video won’t play. (Damn thing won’t let me listen to the latest Offspring CD because of the bonus video). Yet, the $50 Daewoo in the bedroom will play anything I rip from the net.

You need to get up to speed and get a DVD player in that cave of yours. :smiley:

Oh, and stop clubbing the womenfolk over the head and dragging them home by the hair. :wink:

8

I read this three times, and saw “Toaster” instead of “Theater” and thought you were being snarky.

Oh and Elenia, I don’t hear that line nearly as much as I would have hoped.

9

No doubt! I frequently amaze people when I mention I have no DVD player!

And something deep inside me makes me want to let you know I am female.

:slight_smile:

10

WOW! Lesbian cavewomen! :eek:

11

I realize now I completely misunderstood your statement about not having a DVD player as meaning “on your computer”.

:smack: It’s Friday, feel free to ignore me.

12

Then they probably won’t play in a standalone DVD player. Although the video encoding for DVDs is MPEG 2, and some MPEG 2s have the .mpg extension, DVD standard video usually has .dat extensions.

13

A music CD and a CD-ROM are two different things (and a CD-R makes three). While most CD-ROM drives can read CDs perfectly happily, the opposite is not true. The medium is the same (physically, it’s the same kind of disk/disc, but the data is encoded differently).

What you have is a DVD-ROM with computer data on it, not a DVD. It will play fine on a computer, but the data is not necessarily of “DVD quality” (if that actually means anything). Again, a DVD containing video for a home theater system must use a very specific data format. A DVD-ROM can have anything on it, from music to video to random computer files.

14

Well, since no one has addressed the mpg business, I’ll give it a go.

Since the files on your disk are in the *.mpg format, what you have is a data DVD. I don’t know of any standalone DVD players that will play it. They might exist, I just have never seen one.

One of the reasons this can be really confusing is that the word “format” is used to mean different things. For example, DVD movies are really mpg movies. Rip the .vob files from a commercial DVD and rename them to .mpg and most of the time they will play just fine without special software. The DVD movie format is the mpg format (as opposed to the avi or wmv, etc. format). But then there is also the specific file structure needed for those movies to play on a DVD player (not a DVD drive) which is sometimes called the DVD “format.” So you sorta have the right kinds of files, but they aren’t in the right format to play on a DVD player. You need DVD authoring software to take those files and put them in a format the DVD player will play and of course you would need a DVD burner to then burn them to a DVD disk.

Have fun!

15

Beaten to the punch… twice! :smack:

16

Neat. Who’s got a DVD of that?

17

You’re not the secretary I work with, are you? 'cause I had to help her set up an A/V projector room earlier this week, and she disclosed she had never used a DVD player before as well. :eek:

18

What color is the data side of the disc? DVD-R’s are always purple. CD-R’s can be silver, gold, blue or green. (Of course, this doesn’t apply to commercially made CD’s & DVD’s, which are always silver.)

19

There is considerable variation between consumer DVD players in terms of both media and the codecs (coder-decoder) types they can handle. I suggest researching this topic at Videohelp.com. They will provide you with the exact detasils, as well as an extensive database of 100s of thousands of user tech reports on the exact capabilities of thousands of models. I’d never buy a DVD palter without checking them (I did once, years ago. It was a great Sony unit, but it had a couple of drawbacks that dramatically reduced its usefulness for me.)

Personally, my favorite DVD player right now is a Philips DVP-642, which plays MP4s and just about anything else I throw at it (including avis on DVD-ROMs). It does have a little trouble with some SVCD videos some colleagues in India sent me, but I believ ethatthis is most likely due to they way they encoded it (they are not experienced) and might be fixed if I applied the latest update patch to my player.

You should be aeware that a true DVD is (currently) always an MPEG-2 encoded disk with a certain file structure. Typically, you can’t just play it “out of the box” on your PC unless you have player software installed (which may have come with your PC). Technically, you can – if you know which file to look for inside the DVD, btu I’m guessing you didn’t go poking around. MPEG4 is a general standard for the next generation, but it’s very broad strokes, and a lot of other popular codecs are just specific versions/settings of the general MPEG4 spec.

Similarly, there are several forms of video recording (VCD, SVCD, KVCD etc) which are just various specs for recording video in a DVD-like format on a CD. They are often quite good, if done well, but never quite as good as a DVD (because a CD only holds 700MB vs 4.7GB for a DVD). Many disks you can play on your computer are really just computer files recorded in DVD-ROM or CD-ROM format. All but a handful of the most recent DVPs will not be able to play such files.

My $50+ Philips DVP-642 can handle DVD-ROM, and most computer multimedia, so I can play a lot of media directly from backup CD/DVDs (of my computer hard drive over the years) – stuff I never expected or intended to play anywhere but on my computer. Not bad for a $50 DVP! {with free shipping from Amazon] But please do your own homework on Videohelp and elsewhere, before buying especially if you’re likely to get your undies in a bunch over a $50 DVP. Different things bug different people.

Personally I recommend my model as an inexpensive starter DVP, with a decent picture and killer all-purpose compatibility. YMMV, but since you won’t pay too much less for any DVP anyway, what have you got to lose? (again, do your homework and read the reviews. )

20

Originally posted by duffer

You wish! :wink:

Originally posted by TellMeI’mNotCrazy

I could have been more clear! Sorry!

Originally posted by rjung

You mean, there are two of us?!?!?

:wink:

No, I’m not the secretary.

Originally posted by KGS

It’s purple. Maybe it’s been graped by The_Grapist!

Anyway, I have investigated further (I spoke with the person who gave me the disc), and, as some of you surmised, they will not play on a standalone DVD player. They are, “in MPEG format, on DVD-ROMs, playable with RealPlayer or Windows Media Player.”

I’ve sure learned a lot in this thread - thanks! Now, another question - if I ever get myself a real DVD disc (of, say a movie or something), will it play on my computer as well as on a standalone DVD player? Again, my computer has a DVD-Rom.