Some time ago I remember using a little programme which calculated bitrate....it was great for fitting mp3's on to my portable.
I cannot find it, Iv'e searched the Forum and tried Google to no avail.
Can anyone help?
auldyin
Full Version: Bitrate Calculator
Thanks for response.
What I was looking for was a little programme which allowed you to calculate the bitrate which would fit eg:
40 minutes of music into 64MB of memory
auldyin
What I was looking for was a little programme which allowed you to calculate the bitrate which would fit eg:
40 minutes of music into 64MB of memory
auldyin
QUOTE (auldyin @ Aug 27 2003, 01:24 PM)
What I was looking for was a little programme which allowed you to calculate the bitrate which would fit eg:
40 minutes of music into 64MB of memory
40 minutes of music into 64MB of memory
The equation for that calculation is fairly simple, would you really want a special program for it?
OK, take it easy. 
(1) The equation:
bitrate[kbps] = space[kbits] / time[seconds]
(2) unit conversions:
time[seconds] = time[minutes] * 60
space[bits] = space[bytes] * 8
space[K] = space[M] * 1024
(3)The equation for other units - (1) and (2) combined:
bitrate[kbps] = 8*1024/60 * space[MB] / time[minutes] = 136.53 * space[MB] / time[minutes]
bitrate[kbps] = 8*1024 * space[MB] / time[seconds] = 8192 * space[MB] / time[seconds]
That's the nice theory, but I'm not sure about two practical details:
-is the Kilo/Mega conversion correct for MP3 bitrates? or is the factor 1000 instead of 1024? does anybody else know that?
-there may be some overhead related to the actual storing of the files, so you might want to do your calculations with some "headroom". for instance, add a minute or two to the real time. this gives you a slightly lower bitrate (smaller files). just test it for yourself to see how much the "ideal" factor has to be adjusted.
Have fun!
QUOTE (smack @ Aug 27 2003, 03:15 PM)
-is the Kilo/Mega conversion correct for MP3 bitrates? or is the factor 1000 instead of 1024? does anybody else know that?
HDD space:
1 MB = 1024 KB
1 KB = 1024 Bytes
Bitrate:
1 kbps = 1000 bits/sec.
=>
bitrate[kbps] = 8*1024*1024/(60*1000) * space[MB] / time[minutes] = 139.8 * space[MB] / time[minutes]
bitrate[kbps] = 8*1024*1024/1000 * space[MB] / time[seconds] = 8388 * space[MB] / time[seconds]
Thanks guys....................doddle!!!!
auldyin
auldyin
Frontah can show target ABR bitrate: http://home.vxu.se/mdati00/frontah/
QUOTE (NeoRenegade @ Aug 27 2003, 04:59 PM)
Ph34r my gh3y HTML skillz.
Just hit the http:// code button dude. Then you \/\/][|_|_ B3 4|3|_3 70 |>0$7 |_][|\|]{$ |_][]{3 4 1337 |-|4><0R.
SEE!!
Translation: . . . will be able to post links like an elite hacker.
QUOTE (Lodgikal @ Aug 27 2003, 08:36) 
HDD space:
1 MB = 1024 KB
1 KB = 1024 Bytes
Bitrate:
1 kbps = 1000 bits/sec.
=>
bitrate[kbps] = 8*1024*1024/(60*1000) * space[MB] / time[minutes] = 139.8 * space[MB] / time[minutes]
bitrate[kbps] = 8*1024*1024/1000 * space[MB] / time[seconds] = 8388 * space[MB] / time[seconds]
1 MB = 1024 KB
1 KB = 1024 Bytes
Bitrate:
1 kbps = 1000 bits/sec.
=>
bitrate[kbps] = 8*1024*1024/(60*1000) * space[MB] / time[minutes] = 139.8 * space[MB] / time[minutes]
bitrate[kbps] = 8*1024*1024/1000 * space[MB] / time[seconds] = 8388 * space[MB] / time[seconds]
If anyone is still interested, here is a simple batch script using those methods for video bitrate calculation. Simply copy the code below into "Video_BITRATE_Calc.bat" and run whenever desired.
In this script I am forcing the results to be displayed as even integers. If you would prefer to allow odd integers when they are produced, simply delete these lines:
- SET /A _output/=2
- SET /A _output*=2
- SET /A _video/=2
- SET /A _video*=2
CODE
@echo off
color 02
title Video BITRATE Calc...
cls
echo.
echo -----------------------------------------------
echo Video BITRATE Calc...
echo -----------------------------------------------
echo.
echo PLEASE NOTE:
echo 1) Time = MINUTES (every six sec = 0.1 min)
echo 2) Bitrate = CBR (Constant bitrate in kbps)
echo 3) Size = MiB (file size as shown on drive)
echo 4) Output is adjusted to show EVEN integers
echo.
echo -----------------------------------------------
echo.
set /P _time=. Play Length:
set /P _audio=. Audio Bitrate:
set /P _size=. Desired Size:
SET /A _output=(( 8388 * _size ) / ( _time * 60 ))
SET /A _output/=2
SET /A _output*=2
SET /A _video=( _output - _audio )
SET /A _video/=2
SET /A _video*=2
echo.
echo -----------------------------------------------
echo.
echo OVERALL Bitrate: %_output%
echo VIDEO Bitrate: %_video%
echo.
title ... finished!
pause
color 02
title Video BITRATE Calc...
cls
echo.
echo -----------------------------------------------
echo Video BITRATE Calc...
echo -----------------------------------------------
echo.
echo PLEASE NOTE:
echo 1) Time = MINUTES (every six sec = 0.1 min)
echo 2) Bitrate = CBR (Constant bitrate in kbps)
echo 3) Size = MiB (file size as shown on drive)
echo 4) Output is adjusted to show EVEN integers
echo.
echo -----------------------------------------------
echo.
set /P _time=. Play Length:
set /P _audio=. Audio Bitrate:
set /P _size=. Desired Size:
SET /A _output=(( 8388 * _size ) / ( _time * 60 ))
SET /A _output/=2
SET /A _output*=2
SET /A _video=( _output - _audio )
SET /A _video/=2
SET /A _video*=2
echo.
echo -----------------------------------------------
echo.
echo OVERALL Bitrate: %_output%
echo VIDEO Bitrate: %_video%
echo.
title ... finished!
pause
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