Results 1 to 5 of 5

Thread: Calculate Bitrate

  1. #1
    Join Date
    Oct 2011

    Default Calculate Bitrate

    Everytime I create a movie in Premiere Pro and export it to .flv I need to insert a Bitrate which is logical.
    So I use an online calculator that works just fine (Flash Video (FLV) Bitrate Calculator)

    But to get a little more advanced I want to know how the bitrate is calculated.
    I've Googled for a couple of minutes to be honest, but maybe someone has the answer for me and saves me some time.


  2. #2


    I found this if it helps.

    Manually calculate the bitrate
    The basic bitrate formula is

    (Size - (Audio x Length )) / Length = Video bitrate L = Lenght of the whole movie in seconds
    S = Size you like to use in KB (note 700 MB x 1024 = 716 800 KB)
    A = Audio bitrate in KB/s (note 224 kbit/s = 224 / 8 = 28 KB/s)
    V = Video bitrate in KB/s, to get kbit/s multiply with 8.

    8 bit = 1 byte.
    1024 = 1 kilo in the computer world.

    90 minutes video, L = 90 x 60 = 5 400 seconds
    700 MB CD but be sure that if fits use a bit lower like 695 MB, S = 695 x 1024 = 711 680 KB
    Audio bitrate, A = 224 kbit/s / 8 = 28 KB/s

    (711 680 - (5400 x 2 ) / 5400 = 104 KB/s x 8 = 830 kbit/s.

  3. #3
    Join Date
    Oct 2011


    Ah great. I'll check it out in a bit!

  4. #4
    Join Date
    Oct 2011



    I've tried this, but this calculates for the export on a 700 MB CD. I need to calculate the Bitrate for a .fv file based on the aspect ratio. So I don't know the filesize maximum.
    I am going to Google my ass of to find it. If there is someone who knows... Please!

    Thnx Midnight Blue

  5. #5


    I recommend contacting the site's owner to find the maths they have used in the online calculator.
    Even so, that calculator is only a rough guide - and I am not at all sure how accurate it can be. The User must select the appropriate 'motion' dropdown from "slow/Medium/fast'. It makes a huge difference in the results; as does the choice of codec (e.g. Sorenson). I don't know the algoritham used in FLV files, but I can accept that, bit for bit, wider aspect ratios may be easier for codecs to compress (and therefore use lower bitrates).

Similar Threads

  1. bitrate vs resolution?
    By ppkotv in forum Technology advice and tips
    Replies: 0
    Last Post: 06-30-2010, 08:55 AM
  2. Bitrate??
    By necrokill in forum General video editing software help and advice
    Replies: 1
    Last Post: 05-03-2010, 09:57 AM
  3. Can I calculate the Focal Length of a cam lens?
    By TimAndrews in forum Hardware Problems
    Replies: 4
    Last Post: 11-10-2009, 08:10 PM
  4. Unsupported bitrate
    By Similac in forum Adobe Premiere, Premiere Elements, and After Effects
    Replies: 2
    Last Post: 10-24-2005, 06:31 PM
  5. Why is .WMV bitrate so high?
    By GrandMasterKaja in forum General video editing software help and advice
    Replies: 6
    Last Post: 07-04-2005, 02:27 PM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts