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Modérateurs: Modération Forum Home-Cinéma, Le Bureau de l’Association HCFR • Utilisateurs parcourant ce forum: Nicoulasss et 59 invités
» 20 Juin 2006 16:22
Don Eklund, senior vice president of advanced technology for Sony Pictures a écrit:Advanced formats don't necessarily improve picture quality.
Our goal is to present the best picture quality for Blu-ray. Right now, and for the foreseeable future, that's with MPEG-2.
» 20 Juin 2006 16:30
» 20 Juin 2006 17:06
Laprodex a écrit:Don Eklund, senior vice president of advanced technology for Sony Pictures a écrit:Advanced formats don't necessarily improve picture quality.
Our goal is to present the best picture quality for Blu-ray. Right now, and for the foreseeable future, that's with MPEG-2.
http://www.pcpro.co.uk/news/80953/last- ... luray.html
» 20 Juin 2006 17:54
» 20 Juin 2006 17:54
» 20 Juin 2006 18:05
wopr a écrit:Pardonnez-moi si la réponse a déjà été donnée mais quelle est actuellement la taille moyenne d'un film sur HD-DVD et sur BRD ?
» 20 Juin 2006 18:42
» 20 Juin 2006 19:24
melanor a écrit:en plus de part leur conception les BD seront beaucoup plus fragiles que les HD car data très/trop près de la surface... et donc non réparables (les HD si) et donc non louable en Vidéoclub. donc pour moi et d'autres confrères vidéoclub le BD ne sera pas en location. ...
» 20 Juin 2006 19:33
onkyo10 a écrit:remaisisquo vient de nous pondre une page en entier de test, qu'est ce que tu veux de plus?
Un seul pour 4 pages, heuresemment il est sur la premiere page, mais pour les suivants tu fait comment pour les trouver ?, certains topics font des dizaines voire centaines de pages.
les utilisateurs en Europe sont tous HD et ça compte sur les doigts des deux mains et un seul BR qui vient d'arriver...
c'est justement pour ça qu'il faudrait les épinglés, ils sont si rares.
si tu veux les avis d'utilisateurs, va sur les sites de ventes comme Amazon et d'autres mais sera en Anglais...pour les avis Européens , eh bien ils sont contents et toi tu dis qu'on est pro hd..à part ça on parle de technique et tu dis que tu comprends pas..tu sais le choix est limité
Je n'ai pas dit pro-HD , dans tous les topics de tous les forums sur le hardware il y'a des rivalités, et je n'ai pas dis non plus que je ne voulais pas de débats techniques, mais réserver à certains genres (commes les tests des utilisateurs du forum), une page dédié, par exemple.
» 20 Juin 2006 20:09
mynameisfedo a écrit:ouais, sauf que là certains vont te rétorquer qu'il y a la fameuse couche de protection de la mort qui tue développée par TDK et qui garantit la bonne tenue du support même en cas d'attaque nucléaire...
c'est quoi déjà le nom? duralex?
DURABIS2 is not being used for BD-ROM--too time consuming to apply and too expensive to be a viable ROM solution (TDK is using it for their BD-R/RE media). Each replicator is using a semi-custom home brew to create the hardcoat required for BD-ROM, with some base level of scratch resistance and varying resistance to dust and fingerprints. "Naked" BD-ROM discs can never be released--they are too easily damaged.
» 20 Juin 2006 20:21
b2b talks about DVD technology as if it is a bad thing because it is tried and proven. I suspect he thinks round wheels are a bad idea and we should adopt square ones soon
Seriously, let's take a quick look at optical manufacturing and you see that DVD is a brilliant technology. And one that fully merits enhancements in the form of HD DVD.
DVDs introduced a concept which when one first hears it, seems non-plausible. That to make a dual layer disc, you make each half, and then glue them together with the recording layers facing the inside. But a magical thing happens when you do this. Material science tells us that when one forms each half from molten resin, a 0.6mm substrate cools much faster than a 1.1mm substrate that was used for CDs prior to that (half the amount of mass needs to be cooled in DVD). This means that discs can be produced at a faster rate than was possible with even CDs before it. This is the reason the “cycle time” of DVDs is actually faster than CDs.
BD ditches the DVD structure and goes back to CD model. It uses a thick 1.1mm substrate like the CD. But unlike the CD, it records at much finer pitch which means that the cover layer, which goes over the pits, now has to be of much higher level of uniformity. Sony made the initial prototypes with specialized film. But this film expensive and just putting film on your window, it can have imperfections under it, causing yields to go down. One can see the effect of thick substrate in BD cycle times that are 50% slower than HD DVD/DVD.
Spin coating is supposed to remedy the above problem with yields but here, we have yet another challenge. Spin coating works by spinning the disc (hence the name) and putting a single drop of resin on the inside and having the centrifugal force carry it to the outside. The problem with this is that the resin thins out on the outside and dams (pools) on the outside. BD, because of its finer pitch, requires very low tolerances for this cover layer and variations put it out of spec. Hence the reason spin coating is still stuck in the lab despite claims of BD companies that it was ready last year.
And unlike the DVD (and hence HD DVD) where the recording layers are on the inside of the sandwich, protected by 0.6mm of resin, BD only has a .1mm cover layer. This means that some level of protection needs to be applied to the disc to guard against fingerprints, dust, etc. Unfortunately, if you take a perfectly good disc and try to apply some coating on it, you are going to damage some and your yields go down even more. This is why BD yields are so low that no one will mention them on the record or without double-speak.
Now, all of this is for single layer BD! We have a process that is more complicated, is slower, and has lower yields by definition and we haven’t even tried to put the second layer on it. Adding that layer complicates things a lot more. Plus you have a lot of grief mastering such delicate discs.
Going back to b2b’s assertion of BD being new technology, I hope you see that we have the best case of “back to the future” here. BD throws away the good things about DVD and goes to CD style thick substrate. And then complicates things further with finer pitch and far tighter tolerances.
Yes, BD is radically different than the DVD. But per above, this doesn’t make it good. Nor is it “new” because it borrows from CD process, instead of DVD.
As an aside, it is useful to look at UMD for Sony’s PSP. That process used .3mm recording to ease the above difficulties. If BD recording at .1mm works so well, why didn’t Sony use it on PSP? Makes you wonder. Ha?
» 20 Juin 2006 20:42
je n'ose imaginer la durée de vie d'un jeu ps3 entre les mains des kids... clairement le BD est mal baré. 
» 21 Juin 2006 0:44
Laprodex a écrit:wopr a écrit:Pardonnez-moi si la réponse a déjà été donnée mais quelle est actuellement la taille moyenne d'un film sur HD-DVD et sur BRD ?
http://www.homecinema-fr.com/forum/view ... cfe616cc81
» 21 Juin 2006 1:27
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