bit calculation formula

[silentshadow420]

can someone help me with my bit rate calculation formula
i'm going to whip up a vb standalone.exe program to calculate in all different formats.
i was provided this information in the forum prior to this.

Bit conversions:
divx3~> 1 kbs = 1024 bit
divx4,5.x~> 1kbs = 1000bits

given 1bit = .125bytes; 1 byte = 0.0009765625 kilobytes;
1 kilobyte = 0.0009765625 mega byte
then
shouldn't this be accurate
the formula runs down the page sorry couldn't think of a more organized way to post it
-------------------------------------------------------------------------------
legend: * is multiplication, = is equals
-------------------------------------------------------------------------------

movie length
*
chosen bits per sec
*
codec specific bit conversion
*
0.125
*
0.0009765625
*
0.0009765625
=
mega bits per movie

-------------------------------------------------------------------------------
please do not get insulted by the simplicity of the formula. just wanted to prevent any confusion

do you also now convertion factor for wm8 and xvid (i'm assuming they would fall under the divx4,5.x)
thanks for any help this provides

[khp]

Yes, your formula should give the size, of the video stream, in MB. Ofcause you also need to think about audio and avi file overhead.

If you want to know the formulas that GordianKnot uses, you can find them in this thead.

http://forum.doom9.org/showthread.php?s=&threadid=22714

[silentshadow420]

audio

is there a place to get the conversion factors or just size requirements for the complete cd size e.g. ogg, mp3

[khp]

No, the best way to figure that out is to do lots and lots of testing.

[benderman]

But no programmer would use that floatin-point-expressions. The simple formula is:

DivX3:
MovieLengh[sec]*Bitrate[kbps] / (8*1024) = Filesize[MB]

DivX4/5:
MovieLengh[sec]*Bitrate[kbps] / (8*1024) * (1000/1024) = Filesize[MB]

The Result is in MegaByte not MegaBit and the bitrate is always given in KiloBit.

[silentshadow420]

recheck the math

i decided to take the division out of the formula.
i believe this should be accurate still.
wanted to take the confusion out of the formula.
easier to use just multiplication