Bitrate calculating!

[Thomas - MacFreak]

Hi!

I'm have tried to calculate the video bitrate my self, but I did not get the exact filesize I expected. This is how I calculate the video bitrate.

Let's say I want a 700MB file. This is what I do to find out what video bitrate I should use to get the best quality.

Desired File Size : 700MB
Video Length : 119 Minutes
Amount of CD's/files : 1CD
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700MB * 1048756 = 734003200 bytes
734003200 bytes * 8 = 5872025600 bits

119min * 60 = 7140 seconds
5872025600 bits / 7140 = 822412,5490196078 bits

822412,5490196078 bits / 1000 = 822,4125490196078 kbit
822,4125490196078 kbit - 160 kbit = 662,4125490196078 kbit
822,4125490196078 kbit - 128 kbit = 694,4125490196078 kbit

The Video Bitrate should be 662 kbit/s if I have the Audio Bitrate set to 160 kbit/s.
The Video Bitrate should be 694 kbit/s if I have the Audio Bitrate set to 128 kbit/s.

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I tried to use this method on one of my DVD's, and I thought I would get exactly the filesize I wanted, but no! The filesize became 713,8MB (748511038 bytes) and not 700MB as expected.

What can I do to calculate the exact file size? What else do I have to consider then this calculation which should be right ? Please help me...! I'm soon going to release a DVD Rip tutorial (I will post the link to my DVD-rip tutorial here in this forum this week)!

[Thomas-MacFreak]

Can anybody answer this ? Can anybody help me ?

[Baldrick]

It depends what divx,xvid or other codecs or encoders you are using.

Divx 3.xx assumes that 1 kbit = 1024 bits.
Divx 4+(and probably also xvid) assumes that 1 kbit=1000 bits.
Most encoders and codecs uses 1 kbit=1000 bits.