Image Processing Reference
In-Depth Information
29.9.7
Planning Storage Capacity Around DVD Projects
Suppose you are planning to deliver a DVD product and want to assemble a collection of
assets into a disk image before burning it. DVD media comes in a variety of sizes. You
could choose to master to a single-sided, single-layer disk and store 4.7 GB on it. Dual-
layer disks hold approximately 9 GB. Double-sided disks are multiples of these capacities
according to how many layers there are in total.
You need to allow for the content to be processed and stored at each stage of the pro-
duction process. Creating a 4.7-GB disk requires much more space than that to retain all
the intermediate copies.
Burning the disk is going to be based on copying an image of it from your hard disk
to the writable media. Whether you create that image or the software that writes the disk
does it, you need the space reserved. It is a good idea to build the image yourself to run it
in preview mode for testing. Professional software like DVD Studio Pro maintains that
image as a project that you can modify and preview before committing to a burn.
Make sure to keep at least one backup copy so the changes can be reverted. You
won't have worked on the assets in place in the project, so there must be at least one
more equivalent DVD's worth of space for the assets in their raw form before they are
assembled into the DVD project master image. Most of the content of a DVD will be
video. The 4.7 GB is compressed video. The uncompressed footage will occupy signifi-
cantly more space. Five minutes of MPEG-2 video at a quality equivalent to DVD con-
sumes about 150 MB. At DV quality, which is what you might use for editing, that same
footage occupies at least 1 GB. At broadcast-studio quality, it might consume 5 or 6 GB.
Multiply that up from 5 minutes to 2 hours and you have video files in the region of 100
to 150 GB in size. And that's just for one copy! Table 29-1 enumerates some capacities for
a variety of DVD-layer formats and assumes that the storage calculations are based on
professional studio-quality mastering. You may get away with less storage for editing
home movies.
The uncompressed video component uses the bulk of the space. You should choose
an editor that will perform non-destructive edits on this using an EDL or reference
movie that retains all the source components intact. Even then there will be unused
footage in our editing project, which increases the storage requirements by perhaps
another 50%. By the time you have completed a 4.7-GB DVD, you can easily have used
250 GB of space.
Table 29-1 Project Sizes for Storage-Capacity Planning
Item
Single layer
Double layer
Two sides (four layers)
Master copy
5 GB
9 GB
18 GB
Raw assets
5 GB
9 GB
18 GB
Uncompressed video
150 GB
270 GB
540 GB
Total
160 GB
288 GB
576 GB
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