How do you calculate bitrates separately?

[perdomot]

I see lot of people process the video and audio separately but how do you figure out what the bitrate is for each one so you don't go over the maximum space on a cd? I make XVCDs and try to get as much out of the bitrate as possible. Thanks.

[mats.hogberg]

It's simple addition or subtraction. Total bit rate=video bit rate + audio bit rate. If you encode them separately and multiplex them later, or encode+multiplex in one go doesn't matter.

/Mats

[DJRumpy]

I just use a bitrate calculator with both audio, and video calculators. If you know what bitrate you will be encoding your audio in, then you can plug the numbers all in at once. The calc right here on dvdrhelp is good.