Why don't studios fill the DVD?

[TBoneit]

I couldn't decide if this went here or DVD authoring....

Now my question if anyone knows for sure.

Why when a commercial pressed DVD is manufactured be it a DVD5 or DVD9 why do they not use all of the disk? Is the cost of mastering that high? Example I just looked at a DVD that runs 56 minutes. It uses 2.7Gb, whereas if I were creating it at home I would use the max bitrate for quality and still not quite fill the disc.

I know they use better encoders than I run at home but why not use the maximum bitrate since it would fit on a DVD 5. Another example most DVD9 DVD are also not filled even though they could be by using a higher bitrate.

I'm sure it comes down to money somewhere in the process but are they really saving that much money?

TTFN

[dphirschler]

56 minutes, you can max out the bitrate at cbr and still not use the entire disc.


Darryl

[kschang]

Not all players can play stuff at max bitrate.

[cd090580]

It's better to keep the disk not full rather than filling it with crap bonus (always in VOST so they don't interesting me) and it's easier to make a backup

[Bix]

I'm baffled by dual layer DVDs that barely have more than a full single layer DVD on them. I have a Wallace & Gromit DVD that's something like 4.6 GB.

[Richard_G]

When pressing commercial DVD discs there is no difference between a DVD9 and a DVD5. Why bother with different discs for the odd product when all the others need the extra space.

[adam]

kdschang all dvd players are required to play full bitrate DVDs. Any DVD player that cannot play a DVD at max bitrate is defective. For that matter, I'd be suprized if you could even find a commercial DVD that doesn't have a bitrate spike to a full 10.08MB. So if a player couldn't handle this then it wouldn't be able to play any DVD at all. Maybe certain players have problems with burnt media above a certain bitrate but this is not applicable to commercially pressed DVDs.

As for why discs aren't filled, its probably just logistics. Its not like they necessarily have all of the bonus features and other content laid out in front of them when they start producing the DVD. They may need to finish up certain items while leaving room for others when they get them. In the end its not worth redoing things to increase bitrate.

They may also use customized GOP Matrices that are optimized for a certain bitrate. So even though they could throw more bitrate at the movie, they choose not to.

Finally, the feature is usually broken up into scenes and bitrate is allocated manually. Its really not necessary or practical to try to fill up the disc when you encode this way.

It is baffling why they sometimes just barely go over the size of a DVD5. I imagine they could save a substantial amount of money by keeping it single layer. Like I can't help but shake my head at the Baby Einstein DVDs. They all have 3 languages and not all that much changes except the audio. Yet they store the entire film once for each one, necessitating a DVD9. With some simple multi-title authoring they could easily keep identical quality and fit it on a DVD5 with about 2 gigs to spare.

[adam]

Richard_G there is a substantial difference in the process of making a DVD5 and a DVD9, and as a result DVD9s cost more to produce. Check any commercial replication plant and you pay a premium for double layer discs. Multipled across several runs of many thousands I'm sure the amount saved by using DVD5s is significant.

[edDV]

I think it's just poor project planning. Many use hardware encoders and don't bother to use the equivalent of our bitrate calc. They just use defaults.

Another reason could be the guy doing the encoding wasn't given a DVD authoring plan so he just made a good encode from his view of the project. He wouldn't know that the result forced a second layer because of the director commentary and promo that was added last minute. Other combinations of project planning screwups abound.

Once the error has been made. The disaster recovery team may calculate that adding a second layer is cheaper than starting over with encoding and authoring. They bite the bullet, recommend that the project manager be demoted and move on.

[churchie04]

kdschang all dvd players are required to play full bitrate DVDs. Any DVD player that cannot play a DVD at max bitrate is defective.

My network card handles "technically" 100mbit of information. But maxing that out causes my PC to slow down, I wouldn't say my computer or network card is defective though.

[Bodysurf]

kdschang all dvd players are required to play full bitrate DVDs. Any DVD player that cannot play a DVD at max bitrate is defective.

My network card handles "technically" 100mbit of information. But maxing that out causes my PC to slow down, I wouldn't say my computer or network card is defective though.

Doesn't matter -- what he wrote was true:

Any standalone DVD player that does not play valid pressed or replicated DVD-Videos that fall within the specs is DEFECTIVE.

[Wile_E]

I did a test disc a while back with 9800kb CBR video and 256kb audio = 10056kb. This puts it close to the 10080kb maximum. My player and my friends players all played them fine. If a player can't sustain this rate, it definitely does not meet the DVD specs.

The DVD Superbit discs use higher bitrate. But I don't own any, so I'm not sure if they max out the capacity of the discs.

[Richard_G]

Richard_G there is a substantial difference in the process of making a DVD5 and a DVD9, and as a result DVD9s cost more to produce. Check any commercial replication plant and you pay a premium for double layer discs. Multipled across several runs of many thousands I'm sure the amount saved by using DVD5s is significant.

That may have been the case in the past but I've just checked 4 different ones and none differentiate. Once the glass master is made the pressing process is identical.

[Noahtuck]

I did a test disc a while back with 9800kb CBR video and 256kb audio = 10056kb. This puts it close to the 10080kb maximum. My player and my friends players all played them fine. If a player can't sustain this rate, it definitely does not meet the DVD specs.

The DVD Superbit discs use higher bitrate. But I don't own any, so I'm not sure if they max out the capacity of the discs.

That made me think about something back when i was messing with "revenge of the sith" dvd.
I know that it was above the so called "maximum" bitrate of "Total bitrate including video, audio and subs can be max 10.08 Mbps (10080 kbps)"
And that was just the audio & video & not a Superbit dvd.

I checked 2 of my Superbit dvd's and just the audio & video combined are a total of 10248kbps, no subs ect. just the audio & video.

[SLK001]

The DVD Superbit discs use higher bitrate. But I don't own any, so I'm not sure if they max out the capacity of the discs.

Superbit discs still must meet the DVD spec (it is a marketing ploy).

A DVD player reads data off the disc at a constant rate of 26.16 Mbps, regardless of the encoded bitrate. This occurs whether the disc is pressed or burned. To say that your DVD player "can't play discs with high bitrates" is a non sequitur.

[adam]

My network card handles "technically" 100mbit of information. But maxing that out causes my PC to slow down, I wouldn't say my computer or network card is defective though.

How is this even remotely relevant? Your computer + network card is not a unified standard that sets minimum standards of performance. Your computer is not required to avoid being a bottleneck when using that card. Your card is not required to avoid slowdown on all compatible PCs.

DVD is a standard and that standard sets minimum requirements and then allows for certain options. Playback at constant bitrates up to the maximum allowed is a requirement of the DVD specification, period. If a player cannot do this then it will not pass licensing standards. If a model is licensed as a "DVD Player" and a particular unit fails to meet this minimum requirement than it is indeed defective.

Richard_G: It is the making of the glass master that is the complex part, and naturally the most expensive phase of the entire process. As I stated, manufacturing DVD9's is more complex and more costly than manufacturing DVD5's. This is how it has always been. Do you know of any replication plants that don't charge more for DVD9 production than DVD5 production?

[jman98]

TBoneit - You raise a very good question. For example, Akira Kurosawa's _Dreams_ is barely bigger than a single layer. I think it's 4.7 GB. There are no extras on it except for maybe a trailer and a couple of text things that talk about the film. My guess is that whoever prepared it for DVD overshot a single layer by a slight amount and decided it wasn't worth the time to re-encode when his bosses wouldn't notice that it was barely too big for a single layer DVD.

It could also be that in some countries, DVD-9 is automatically perceived as being "higher quality" than DVD-5. While this is certainly true in many cases, in the case of the Wallace and Gromit DVD, I don't think there would be any appreciable difference between a single layer DVD and the 4.6 GB dual layer DVD. Maybe in some cases they try to get a dual layer DVD out of the movie, even though it's not necessary, just to not appear cheap. I know that in Russia they sometimes sell 2 versions of a movie - a cheaper DVD-5 and a more expensive DVD-9 version.

[adam]

I think it was R1 Lilo and Stitch where they used a DVD9 even though the total amount of data didn't even fill a DVD5. They just spread like 4 gigs across two layers for no particular reason. I think the individual production houses that are hired simply make stupid mistakes sometimes. Its not their money.

[edDV]

The DVD Superbit discs use higher bitrate. But I don't own any, so I'm not sure if they max out the capacity of the discs.

...

A DVD player reads data off the disc at a constant rate of 26.16 Mbps, regardless of the encoded bitrate. This occurs whether the disc is pressed or burned. To say that your DVD player "can't play discs with high bitrates" is a non sequitur.

Someone in this forum explained the failure mechanics this way. Read failures occur not because the laser can't maintain the 26.16 Mb/s raw transfer flow (typical of media errors) but because a buffer overflows causing repeated rereads thus creating jerky playback. That seemed plausable but I have no first hand knowledge.