Bitrate Calculate.. too big ?!

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  • BlacKRaiN
    Junior Member
    Junior Member
    • May 2002
    • 13

    Bitrate Calculate.. too big ?!

    Hey !! I used flakmpeg to do my dvd - divx convertion.. and as for the Divx bitrate I used 602 kps .. wich my calculator gave me as a perfect fit for 1 700 Mb cd... yet my final movie is 798 mb :| !! How come ?!
    The quality is nice thought... sound perfect (mp3 128) video nice (23 fds, 720/400) 134 Minutes

    Please help
  • UncasMS
    Super Moderator
    • Nov 2001
    • 9047

    #2
    thats just the way a codec 'behaves'

    take a look at guides like nickys
    (can be found in the VERY TOPMOST posting in this board)

    Comment

    • BlacKRaiN
      Junior Member
      Junior Member
      • May 2002
      • 13

      #3
      But then.. how do I anticipate the end size of my newly compressed dvd to divx movie ?!

      Comment

      • khp
        The Other
        • Nov 2001
        • 2161

        #4
        Re: Bitrate Calculate.. too big ?!

        Originally posted by BlacKRaiN
        sound perfect (mp3 128) video nice (23 fds, 720/400) 134 Minutes
        wow, that's like 0.089 bits per pixel, you should go for 2 CD's or reduce the res to something like 512*288.

        Which codec did you use, and did you use 1 pass or 2 pass encoding ?.
        Donate your idle CPU time for something usefull.
        http://folding.stanford.edu/

        Comment

        • BlacKRaiN
          Junior Member
          Junior Member
          • May 2002
          • 13

          #5
          Used Divx 5.0 Pro

          I'm guessing 1 pass I just did.. Flak it.. and voila (once) so.. 1 pass !! And if I do it on 2 cd's.. how much kbps should I use ?!
          Which calculator should I use to really get the perfect bitrate to get the real final size ?! etc ?! Thankx

          Comment

          • BlacKRaiN
            Junior Member
            Junior Member
            • May 2002
            • 13

            #6
            Okay so... everytime I calc in Divx Calculators.. it tells me 585 kbps...to fit in 700 MB.. but I did it with 602 and that gave me 790 MB... anyway before I Flakmpeg it to know really how many megs am I gonna end up with ?!

            And like I said earlier.. is there any way to really got the appropriate kbps for my movie easily to have great quality ?! (i.e. when to do it on 2 cd's.. of if only one is okay... etc)

            Comment

            • khp
              The Other
              • Nov 2001
              • 2161

              #7
              Well some bitrate calculator, might give slightly differing results, because they calculate the avi file overhead differently.
              According to GKnot the bitrate should be 598.

              585 kbs sounds like you are calculating for divx3 (divx3 uses 1kbs = 1024 bit, divx4/5 uses 1kbs = 1000 bits).

              But to get more precise filesize prediction you must use 2 pass encoding. To do that you must first encode with '2-pass first pass' and then encode again with '2-pass second pass'.
              Donate your idle CPU time for something usefull.
              http://folding.stanford.edu/

              Comment

              • BlacKRaiN
                Junior Member
                Junior Member
                • May 2002
                • 13

                #8
                Ohhh So the trick is 2 pass... does that change quality ?!

                How to we do that using Flakmpeg ?! Should I use another software ?!

                Comment

                • khp
                  The Other
                  • Nov 2001
                  • 2161

                  #9
                  Originally posted by BlacKRaiN
                  Ohhh So the trick is 2 pass... does that change quality ?!
                  Overall 2-pass encoding should produce better quality at the same filesize.

                  Originally posted by BlacKRaiN

                  How to we do that using Flakmpeg ?!
                  I just told you: you must first encode with '2-pass first pass' and then encode again with '2-pass second pass'. (see attatchment)

                  Originally posted by BlacKRaiN

                  Should I use another software ?!
                  GordainKnot is a nice tool for DVD->Divx conversion, but ofcause the choice is yours.

                  Checkout the GKnot divx5 guide at www.doom9.net
                  Attached Files
                  Donate your idle CPU time for something usefull.
                  http://folding.stanford.edu/

                  Comment

                  • BlacKRaiN
                    Junior Member
                    Junior Member
                    • May 2002
                    • 13

                    #10
                    Sorry again
                    But hurm.. you said same Filesize ?! Really... didn't you say earlier that 2 pass would give me a smaller filesize..well closer to the one I got using the calculator ?!

                    But to get more precise filesize prediction you must use 2 pass encoding
                    Overall 2-pass encoding should produce better quality at the same filesize
                    ??? Dont me lol.. thanx really for everything !!!

                    Comment

                    • khp
                      The Other
                      • Nov 2001
                      • 2161

                      #11
                      You are ofcause correct in saying that 1-pass encoding might produce better quality than 2-pass encoding at the same bitrate setting, because the one pass encoder might cheat by producing a much bigger file than the 2-pass encoder.

                      This is exactly why I said filesize, comparing the quality of 2 different encodes based on the bitrate setting is not really usefull, unless both methods can be trusted to produce accurate filesize.
                      Donate your idle CPU time for something usefull.
                      http://folding.stanford.edu/

                      Comment

                      • BlacKRaiN
                        Junior Member
                        Junior Member
                        • May 2002
                        • 13

                        #12
                        Hummmm nice I read alot about GKnot... love it .. but one tiny problem.. I don't seem to find any wayz to do "2-pass" movies with this product.. help please How do I do them.. I do how to do 1 pass no problem.. but 2 ?! :| !!

                        Comment

                        • khp
                          The Other
                          • Nov 2001
                          • 2161

                          #13
                          GordianKnot will automatically do 2-pass encoding, it can't do 1-pass.
                          Donate your idle CPU time for something usefull.
                          http://folding.stanford.edu/

                          Comment

                          • BlacKRaiN
                            Junior Member
                            Junior Member
                            • May 2002
                            • 13

                            #14
                            Ohhhhh.....

                            I look stupid now

                            Comment

                            • BlacKRaiN
                              Junior Member
                              Junior Member
                              • May 2002
                              • 13

                              #15
                              Hurm... I eel shy asking another question.. but here it goes...

                              I tried GKNot... liked it exactp fr the sound part.. I demuxed my ac3 more then once to be sure... so i'm sure the ac3 is fine, but when it come to converting it into mp3 using BeSweet like the guide says so.. I get thrre CRC Errors real quick.. so I get 126 K of Mp3... and my sound doesn't work... any solutions to this or help I could get ?! thanx !!

                              Comment

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