Can anyone define the difference between dvd and cd video
as I am not sure where to find the answer!
The odd ocassion I have asked a member of staff at a local
retail outlet any particular question, they always seem vague
about a reply. It was a computer retail outlet I was talking about
by the way

DVD is mpeg 2 and is very high quality, certainly comparable, if not better than DV. VCD is mpeg 1 and has about the quality of VHS, maybe a little lower. VCD is burned to regular CD's.

Thankyou for your reply Jeff
I am reasonably new to Dv and I am finding it incredibly
interesting and mind blowing at the same time!!

DVD MPEG2 could be better than DV25? How is that?

Jesse is right. DVD is compressed MPEG2 format and retains high quality, but DV signal is still the best. DVD MPEG2 format is burnt onto a 4.7Gb disc and is read at a much higher bit rate than VCD which is highly compressed (MPEG1), can be burnt onto a standard 700Mb CD, and read at a slower bit rate.
SVCD is a mid-term solution that can be burnt on a 700Mb CD, but not recognized by many DVD players.

A regular CD burner can make a VCD or a SVCD, but you need a DVD burner to make an real MPEG2 DVD compatible with most home DVD players.

DVD's that are encoded from higher end formats and encoded on high end hardware (rather than software) look better than material acquired on DV.

Well, 35mm film correctly transfered to almost any format will subjectively look better than DV25, but that doesn't make DVD MPEG2, even at a high bitrate, a superior format.

<<<-- Originally posted by Ian OBrien : Can anyone define the difference between dvd and cd video
as I am not sure where to find the answer!
The odd ocassion I have asked a member of staff at a local
retail outlet any particular question, they always seem vague
about a reply. It was a computer retail outlet I was talking about
by the way -->>>

Ian,

For more of an indepth explanation, have a look at the following url:

http://www.creativevideo.co.uk/pages/cvp_info_mpeg2_dvd.htm

Also, we can see in terms of bit rate, DVD format cannot be higher in quality than DV as the max compression rate for DVD is 10.5 Mbps and for DV, it is 25Mbps.

cheers,
Peter

One thing to remember is that mpeg can be encoded in multi pass and can encode more efficiently, saving space then using more bps when required. Mpeg also references previous and future frames so it doesn't encode the entire frame most of the time.
DV must compress each frame on it's own and as such such uses more bps.

Whether it is better or not? well it depends what you call better. For editing mpeg isn't as good, but for final delivery you are never going to get anything better than the DV original and encoding from one lossy codec (DV) to another (mpeg2) you will always lose quality.
I say 'better' (for me) is being able to take a small disc and play it on my dvd player rather than take out my camera and shuttle tapes endlessly for the sake of a small quality penalty.

A final delivery codec's (like DVD mpeg2) job is to throw away as much data as possible without it being visible. It does a good job (if the encoder is any good) but will never be as good as the camera original of any format.

If both compressed from the same uncompressed source, mpeg2 video would be comparable to DV at much lower bitrates due to it's more elaborate compression (referencing other frames).

In response to the actual question:
Here in Australia I have never seen a DVD player (maybe the very early ones) that can't play VCD and SVCD. I used SVCD before I got a dvd burner and it was ok - I got lip-synch problems on certain players and in frames with a bit of motion the picture broke up into macro blocks pretty easily (even with high bitrates).

I would never use it now because DVD-r disks are so cheap and S/VCD doesn't support AC3 (dolby digital) audio, anamorphic widescreen and other technical niceties. I've never used VCD because, although as Jeff mentioned, it is similar to VHS quality (in static scenes), in high motion areas it breaks up easily into macro blocks. Also the run time of a S/VCD is fairly short and you need to use multiple disks for a feature length movie (~2 for VCD, ~3 for SVCD).

<<<-- Originally posted by Kyle Ringin : One thing to remember is that mpeg can be encoded in multi pass and can encode more efficiently, saving space then using more bps when required. Mpeg also references previous and future frames so it doesn't encode the entire frame most of the time.
DV must compress each frame on it's own and as such such uses more bps.


This thread is starting to deviate but unless I'm mistaken, I still can't see how DVD's maximum bitrate of 10.5 Mbps could be comparable to DV's 25Mbps. The max 10.5 Mbps is applied to a frame and according to that article I previously referenced, all frames are compressed (or are the B frames the frames you're referring to when you say most frames are not encoded).

Anyway, at the end of the day, all is subjective :)

cheers,
Peter

What I meant was that because mpeg2's 10.5Mbps (for example) is not used to encode a full frame (except i frames) the bits can be used 'more wisely' to encode changes rather than information that has been already encoded in the last frame.

I agree this is getting fairly off track. And probably academic. I agree even more that it is all really subjective too. I have a MX500 and an HDTV and I don't think the difference between the camera original and a DVD is much to make a noise about. If your video is interesting enough, no one will notice the compression artifacts...

Peter: you can't just compare bitrates like that, DV is much closer
to MJPEG than to MPEG for comparison.

Think of it in terms of cars. If I have a 200 bhp engine in my car
that tells me nothing. Now if this cars weighs 500 kg (1100 pounds)
you know you'll have a rocket. But if the car weighs 1500 kg
(3300 pounds) it will be far far slower.

Compression is a complex business where bitrates are only
relevant for:

- comparison in quality with the same codec (MPEG2 and MPEG2)
- comparison in quality with codecs of similar algorithms (ie, DIVX/MPEG4)
- comparison in final file size versus. quality

Although MPEG and DV use a similar base frame encoding
techniques there are much more differences and this yields very
different bitrates. As Kyle also tried to explain one of the major
differences is that MPEG is a frame-difference based encoder
which DV is not. So it already has less data to start with.

I have actually burned to dvd a party I originally did for someone
on cd video, and was astounded with the diference! I will avoid
cd video after visually comparin the two, I am not well up on
GB data like you guys, but I appreciate your replies

many thanks

By CD video you mean VCD and SVCD formats (both can be used to record video on standard CD-ROM discs). VCD can be played back on any DVD set top player but unfortunately not all DVD set top players can playback SVCD.

VCD uses MPEG-1, SVCD uses MPEG-2 at higher resulution to obtain a better picture (but you can't fit as much on a SVCD CD-ROM disc of course).

DVD, we all know, uses MPEG-2 at a higher datarates and resolution and needs to be burned on DVD-R/+R discs.

Comparing not MPEG-2 but a DVD disc to DV, DV is better technically as you wind up recompressing your DV stream to MPEG-2 in order to deliver it on DVD. However, a high quality MPEG encoder like Canopus Procoder and using AC3 audio to squeeze the highest video bitrates possible, gives quality comparable to DV. Maybe on a bench it shouldn't, but via viewing tests, believe me, the difference is negligible (however, DV is your "negative" by going DVD you've gone to a lossy format and if you re-edit DVD VOB files, you're compressing once again).

Video CD (VCD and SVCD) ares quite handy during post. If you need to provide a producer with a quick content check of your work and quality is not an issue -- VCD is fine -- all players will play it, in fact VCD might be more compatible then DVD-R (I'll often provide clients with a VCD backup in case they can't play the DVD-R on their set tops. So VCD's are great, they play on any machine, are very cheap and quick to burn.

SVCD by the way, is actually really good. To appreciate the format download DVD2SVCD and try it. I've converted some of my DVD productions to SVCD versions with this tool and the quality is just below DVD (buy a DVD player that is known to play SVCD or you'll be out of luck).