4

• Motion menu video with a duration of 00:00:16:20 and one AC-3 stereo audio stream
• Stage 1: Calculating the Total Video Play Time
• Stage 2: Calculating Disc Capacities
• Stage 3: Calculating the Bit Rates for Each Disc Size
• Stage 4: Calculating the Audio Allowances
• Stage 5: Calculating the Effect of Audio on the Video Bit Rate
• Stage 6: Calculating DVD-ROM Allowances
• Stage 7: Calculating Other Allowances
Stage 1: Calculating the Total Video Play Time
You first need to determine the total play time of all video assets and motion menus in
your project. To make calculations easier, you need to convert the time from hours,
minutes, and seconds to the total number of seconds. For frames, round up to the next
second when there are frames left over.
In the example above, video asset 1 is 5174 seconds long, video asset 2 is 2735 seconds
long, and the motion menu contains 17 seconds of assets, for a total of 7926 seconds.
Note: Slideshows do not count as video play time, and are discussed later.
Stage 2: Calculating Disc Capacities
To calculate the appropriate bit rate for your content, you need to know each disc type’s
capacity in bits. The capacity of a DVD-5 disc is 4.7 GB (or 4.37 binary gigabytes). For the
purposes of this calculation, you should use the 4.7 GB value because it does not have
to be corrected to account for the difference that counting in binary adds. To make the
calculation, you multiply the byte capacity by 8 (the number of bits in a byte).
Bit capacityByte capacityDVD name
11.68 gigabits (Gbit)1.46 GBDVD-1
21.28 Gbit2.66 GBDVD-2
23.36 Gbit2.92 GBDVD-3
42.56 Gbit5.32 GBDVD-4
37.6 Gbit4.7 GBDVD-5
68.32 Gbit8.54 GBDVD-9
75.2 Gbit9.4 GBDVD-10
105.92 Gbit13.24 GBDVD-14
136.64 Gbit17.08 GBDVD-18
636 Appendix C Calculating Disc Space Requirements