[dvd::rip] incorrect bitrate calculation for divx4

[Christian Lambert <clambert@xxxxxxxxxxx>]

Noticed that your movies are a little undersized?

The Divx4 codec assume that 1kbit = 1000 bits (not 1024 bits)
so if you take this into account, the bitrate that transcode
or dvdrip propose is always a little lower than what it should
be and therefore result in slightly undersized movies.

The divx3 codec assumed that 1kbit = 1024 bits.

http://www.doom9.org/divx4calc.htm