Text 1496, 85 rader
Skriven 2004-12-13 08:46:50 av Glenn Meadows (1:379/45)
   Kommentar till text 1492 av Monte Davis (1:379/45)
Ärende: Re: DVD burner & software?
==================================
From: "Glenn Meadows" <gmeadow@comcast.net>

No way.  Very few DVD's are created from DVD-R's (or DVD+R's).  There is one
very expensive grade of DVD for "authoring purposes", but most all commercial
DVD's are made from DLT (Digital Linear Tape) that has all the image files on
it.  The authoring software is typically very complex (and expensive) to create
all the parts of the disk.

The DLT is used to cut the Glass masters required to make the DVD.  In
replication, the dual layers are done as two separate pressings, and glued
together to make the dual layer disk.  Making a dual layer DVD-R style disk is
very complex, because of the burning of the two layers, as well as the
transparency of the disk/glue chemistry.

Typically, if a dual layer disk is being made, the authoring facility makes 2
reference disks, one for each layer, BUT they have to re-make and re-author the
menus to properly link to the second layer for the replicated disk.  The
replicated disk has to be checked after replication to confirm proper
operation.

What's interesting, there is really only one high end company now making all
the software, Sonic Solutions.  They were primarily a MAC company, making audio
editing software, that was derived from the Lucas Film Edit Droid software. 
They moved into DVD authoring, with DVD Creator.  Very cumbersome/awkward and
time consuming to use (still).  Their next product though, was a Windows
product DVD-It, that became the basic bundle with the consumer DVD burners. 
They've made a fortune in that arena.  Next, they bought the largest of all the
Windows software pro authoring software companies, and continue to parallel
develop all the products.

The real kicker/killer in DVD authoring, is the MPEG encoding.  All the
commercial systems take input from various style sources (typically D-2 digital
video recorders), and will take hours to pre-calculate what compression is
needed throughout the whole movie.  I've watched the encoding shuttle the deck
back and forth through complex scenes (lots of motion going on) to achieve the
best compression required to fit in the bandwidth that the disk can handle, as
well as how to encode the audio, so they both fit in the "bit budget" that the
format allows.  The software remembers the compression settings based on the
SMTPE time code of the scene, so that when it goes into the actual encode pass,
it knows what to do.  I've seen 2 hour movies take 14 hours to do a full encode
pass for optimal look.

When we were doing the Shania Twain Come On Over DVD, which is only a 2 hour 15
minute DVD, we had to format the disk as a full dual layer disk, putting a
little over half on the first side, and the balance on the second layer. (There
was a good side change point during a wardrobe change, where the stage was dark
for about 30 seconds.  What killed the encoder, was the constant slow drifting
smoke from the fireworks/pyrotechnics on stage.  At normal compression rates
for putting it on one side, there was constant pixelization across the
background.

Encoders are better now, but still, it's rough getting some of the stuff in.
Also disappointing to hear the audio after being AC3 encoded.  While I think
Blu-ray and the other HD-DVD formats are going to have a hard road ahead, they
will allow far better audio and video to show up.  Seeing a true Digital master
vs. the DVD finished disk on a split screen is very eye opening as to what's
lost compared to what's actually there.

--
Glenn M.


"Monte Davis" <monte.davis@verizon.net> wrote in message
news:k3tqr05fktqrueov00qso2iueedhvrvp41@4ax.com...
> dmhills@attglobal.net (Don Hills) wrote:
>
> >No. Dual-layer DVD is not the same technology as dual-layer DVD-R once
you
> >get beyond the basic principles. New technology always costs more to
start
> >with
>
> I was about to reply "wasn't the commercial DVD that I rent or buy a
> DVD-R when it went into the duplicator?" when
>
> <f/x heel of hand striking forehead>
>
> it occurred to me that no, it was stamped from a master, not digitally
> burned. Thank you for reducing my dumb-idea count by one.
>
> -Monte <every little bit helps>
>

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