DVD Demystified

Essentials of DVD Production
TABLE 12.4
Sample bit budget
Element Time Data rate Size
517
English audio track (5.1) 110 minutes 0.448 Mbps 110�60�0.448 = 2,957 Mbits
English audio track (2.0) 110 minutes 0.192 Mbps 110�60�0.192 = 1267 Mbits
Spanish audio track (5.1) 110 minutes 0.448 Mbps 110�60�0.448 = 2,957 Mbits
4 subpicture tracks 110 minutes 0.010 Mbps 4�110�60�0.01 = 264 Mbits
Total (simultaneous — 1.128 Mbps —
with movie)
2 motion menus and 48 seconds 8 Mbps 48�8 = 384 Mbits
3 transitions (incl. audio)
Intro logos 32 seconds 8 Mbps 32�8 = 192 Mbits
(incl. audio)
Movie preview 2 minutes 4.5 Mbps 2�60�4.5 = 540 Mbits
Audio for preview 2 minutes 0.192 Mbps 2�60�0.192 = 23 Mbits
Interview 3 minutes 4.5 Mbps 2�60�4.5 = 810 Mbits
Audio for interview 3 minutes 0.192 Mbps 2�60�0.192 = 35 Mbits
Total (non-movie elements) — — 9429 Mbits
Space remaining for movie — — 36,096*-9429 = 26,667 Mbits
Movie 110 minutes Avg: 26,667/(110�60) = 4.04 Mbps
Max: 10.08-1.128 = 8.95 Mbps
*From Table 12.3.
warnings should be authored as timed stills, which have no impact on disc
space. Subtract the total size of ancillary material from the disc capacity
minus overhead. This gives remaining capacity for the main program. Calculate
the average video bit rate for the main program by dividing the
remaining capacity by the running time. Also calculate the maximum video
bit rate by subtracting the combined audio and subpicture bit rate from
10.08. These numbers will be fed into the encoder when compressing the
video for the main program. Note that minor elements such as subpicture
tracks and motion menus are usually so small that they can often be omitted
from calculations. If they were left off of the example in Table 12.4, the
average data rate would come out to 4.17 Mbps, which is close enough.
An alternative bit budgeting approach is to divide the disc capacity (in
bits) by the total running time of all segments (in seconds) to get the aver-