Apple DVD Studio Pro 4 - Manual (Page 39)

Capacity Type Disc size DVD name
4.5 GB (4.19 binary
gigabytes) Single-sided,
single-layer 8 cm HD DVD-4
9.0 GB (8.38 binary
gigabytes) Single-sided, dual-layer 8 cm HD DVD-9
15.0 GB (13.97 binary
gigabytes) Single-sided,
single-layer 12 cm HD DVD-15
30.0 GB (27.94 binary
gigabytes) Single-sided, dual-layer 12 cm HD DVD-30
Estimating Whether Your Content Will Fit
While you will often hear that a DVD-5 (or a 4.7 GB disc) can hold two hours of video
content, this is really only a rough guideline. The actual amount of video a DVD-5 disc
can hold depends on the bit rate the video is encoded at. Often overlooked is the size of
audio files—if you plan to use uncompressed AIFF (PCM) audio, you must also take the
additional space requirements into account when calculating whether all your content
will fit.
If your project needs to fit on a DVD-5 disc that you can burn on your SuperDrive, you
need to choose an appropriate bit rate. There is a simple formula you can use. See
Fitting
Your Project on a DVD-5 Disc for more information.
If you are flexible as to the DVD disc type you can use, you can experiment with different
bit rates and determine the disc space required by each. This process is more detailed
and includes more variables, such as taking into account additional audio streams and
DVD-ROM content. See
Calculating Disc Space Requirements for details on precisely
determining your disc space requirements.
Fitting Your Project on a DVD-5 Disc
You can use this simple formula to estimate the bit rate you should use to fit your video
on a DVD-5 disc:
560/x = bit rate
The “x” represents the length of the video (in minutes) and the resulting bit rate is in
megabits per second (Mbps). This formula assumes you are using compressed audio,
such as AC-3. If you are using uncompressed audio, you need to subtract 1.5 Mbps
(assuming you are using 16-bit stereo at a 48 kHz sample rate) from the bit rate value.
For example, if you have 120 minutes of video, you get a suggested bit rate of 4.67 Mbps
(560/120 = 4.67). If you are using uncompressed audio (such as the AIFF format the
embedded AIFF encoder supplies), you need to reduce the bit rate to 3.17 Mbps to ensure
the video and audio will fit on the disc.
39 Chapter 2 Planning Your Project