The following is the formula for calculating the total capacity
needed on a disc if you wish to encode a specific film.

Average Bit Rates: Though bit rates may vary due to complexity
of image and other variables, the following are averages
you may consider in generic calculations.
Video-3.5 Mb/sec,
Audio(5.1)-0.384 Mb/sec,
Subtitles-0.01 Mb/sec

By changing the space allocation for audio and subtitles, we can fit
more than 133 minutes of video onto a single-sided, single-layer disc.