DVD compression question. . .

[MillyFan]

How many episodes of anime can fit onto one DVD without compromising quality?

Basically, I'm looking to buy Gundam Wing on DVD, and there was an advertisement for all 49 episodes on two DVDs somewhere. It sounds like something that's too good to be true. . .is it?

Anyway, after seeing that old thread on DVD compression, I realized that there are quite a few people here who might know about this, so. . .could someone help me here?

[shooraijin]

> there was an advertisement for all 49 episodes on two DVDs somewhere.

Too good to be true. Even if dual layer, dual sided, it would have to be absolutely lousy quality to get more than around twenty on a single disc, assuming the average episode length is about 25 minutes or so (I haven't seen the series ). So, two discs having a total of 49 seems really, really unlikely.

[Rashiir]

It's possible that they used 18GB DVDs,but very unlikely.

[agasfas]

when they have all eps on 2 or 3 dvds (approx: 9gb disc) they are bootlegs/imported from Tiwain or Hong Kong. And usually the picture and or sound quality lacks due to the compression they use. Although i do own/have a couple series that are good and have great video w/ little pixilation (13eps series and a 26episode series). ANd the subs are usually badly done ("engrish"). A lot of the time the dvds are Region 1 dvd rips and compressed a little. But for 49eps on 2 dvds, it may be possible all the eps are in avi form (ripped) and encoded in divx codec and burned on a blank dvd-r/+r.
------------------------

[Kaligraphic]

Note that commercial anime DVDs typically have four episodes per disc. Putting 49 on two discs indicates that these would be ~175-190MB files, and thus probably encoded with DivX rather than the DVD-standard MPEG-4, and are probably the same fansubs that people would have downloaded before the series was licensed. If you're looking for legit DVDs, expect four episodes per disc.

Don't pay for fansubs - the people who did the work don't get paid for fansubs, and if it's licensed for distribution, then the authors have spoken, and deserve their due.

[agasfas]

agreed. I see nothing wrong w/ fansub and shouldn't have to pay for it. But after a series/movie is licensed then people need to stop spreading them/selling them. Usually the fansubbers state:
1) Not to share fansubs after that particular series has been licensed.
2) And their fansubs shouldn't be sold by anyone (b/c it should be free).
And the most number of episodes i have seen on one dvd was 6eps (those who hunt elves).

[shooraijin]

Just as a warning (not that anyone's doing this), but to head this off since we're diverging somewhat from the original discussion: don't turn this into a discussion on the legality of fansubs. This is not directed at anyone in particular -- just don't do it, as this has caused very complex and unpleasant wrangling in the past.

[panegryst]

49 eps per DVD == actually just two copies of Now! 5. rule of thumb: don't buy anything where the numbers don't make sense.

[Azier the Swordsman]

Hmmm... well, my Beast Wars DVDs have about six or seven episodes on each, and the quality is still really good, so I imagine that about maybe seven or eight would probably be the max....

I've heard of some DVD's that have tried to cram 12 or more episodes on one disk though. That certainly can't be good for video quality.

[Technomancer]

I think the most I've ever seen on a single DVD was about 6 for "Fruits Basket". I don't think that fitting 24 episodes of a half-hour show is really possible if it's going to be at all watchable (technically you could fit them all on, if you-re willing to accept some pretty awful rate-distorition figures).

Other than video quality there's also another reason to limit the number of epsidoes: robustness. Redundancy is added to the bitstream according to particular algorithms that allow for forward error correction. This allows for greater robustness in the presence of dust, scratches, etc that might othewise interrupt signal. Adding this redundancy of course means adding bits, which increases the file size. This places an additional constraint on the number of episodes.

[Kaligraphic]

Speaking of which, we may be able to find these kinds of numbers in decent quality published commercially. Having, say, 26 (or at least 13) episodes of something on a disc may become commonplace - and without a reduction in quality. How?

Single-layer DVD discs (like recordable DVDs or software DVDs) hold 4.7GB of data, while movies are often distributed on dual-layer DVDs, which can hold 8.5GB of data.

Blu-Ray (blu-ray.com) is a technology currently in development to surpass DVD capacities. A single-layer Blu-Ray disc might hold 25GB, while a dual-layer disc can hold 50GB. Even more impressive (especially given that even dual-layer discs are quite a technical feat) is that the engineers are studying ways of potentially making quad-layer discs capable of holding 100GB (almost the equivalent of 12 DVDs)!

Of course, the DVD Forum is developing their own higher-capacity disc, called HD-DVD. Indications are that single-layer HD-DVD discs will hold 20GB, while dual-layer HD-DVDs will be able to hold 32GB. (note that these are SI-prefix, or "mathematical" capacities, while Windows will show powers-of-2, or "computer" capacities, meaning that a 4.7GB disc will appear to only hold 4.3GB)

I'm expecting them to premier in the US probably in 2006-07, but some companies are saying they'll release products supporting these standards next year. In five years, maybe instead of buying 7 discs, we'll be able to spend our $150 (or whatever it'll cost by then) on one disc, and still get a whole series. (both technologies will come out in Japan first, because HDTV sets are a lot more common - meaning that the extra capacity will be used for higher resolution video.)

Personally, of course, I'm rooting for Blu-Ray, because of its superior capacity.