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# bit budgeting

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 bit budgeting by Davidon Jan 10, 2006 at 10:44:15 pm

Howdy all,

So I'm working out my bit budgeting for a DVD I'm putting together by following the examples given in the Encore help files.

It says there that in order to determine the maximum video data rate, I need to subtract the combined audio data rates (0.192 Mbps x 22 audio files, in this case, which = 4.224) from the maximum DVD video data rate (9.8 Mbps), which comes out to 5.576 Mbps. Is this correct? That is, do I need to multiply the audio data rate times the number of audio tracks there are in my project?

I only ask because I have come to a calculation of a data rate for my video (34,837.888 Mbits available / 4,920 seconds of video = 7.08 Mbps) that is apparently greater than the maximum video data rate for my disc (5.576 Mbps). Should this be possible? If so, do I just set the data rate for my video to 5.576? Have I miscalculated something? Any help you could give me with this problem would be much obliged. Thanks!

- David

 Re: bit budgetingon Jan 11, 2006 at 12:02:39 am

Bid budgeting is confusing. You don't need to calculate 0.192 by the number of audio files in your project....just by the number of audio TRACKS you have per timeline. I assume you only have one audio track in each timeline. Audio and video bitrates together can be no more than 9.8Mbps.

The way I calculate a bitrate is as follows.
36096 Mbits / 4920 seconds = 7.3Mbps - 1 audio track (0.192) = 7.1 Mbps.
So 7.1Mbps total bitstream will fill your disc with your 82 minute program that cpntains one video track and one audio track per timeline.

This is the calculation I use all the time and it comes very close (because the video bitrate I use is a variable bitrate)