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Strange small Divx video file size

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  • Gugus
    Junior Member
    Junior Member
    • Jul 2002
    • 7

    Strange small Divx video file size

    Hi all!

    I have a new strange problem:
    I'm using FlaskMPEG XiS 3.0e for conversion and Divx 5.02 Pro (add).
    It's not the first time that I do a conversion (I did a lot),
    But here is my problem:

    Trying do convert the movie Stalingrad "Enemy at the gates".
    I using Divx Calculator for estimate the Bitrate
    - Lenght : 125m39s
    - Audio mp3 file: 149 Mo
    - 2 CD (then, I want a video file of 1251 Mo)

    The Divx Calculator give me 1395 kbps.

    When I convert the movie (options QP, GMC and BE enabled) in 2-pass with 1395 kbps.

    My video file do 758 Mo !!! (and not 1251 Mo!!!)

    Then I do a test: I use 2000kbps... and my video file do ... 754 Mo..

    I play the video file.... and the quality seem very good...

    I try with another movie "American Beauty", and I have the same prolem: undersie divx file.

    Where the problem ????
  • benderman
    Digital Video Specialist
    Digital Video Specialist
    • Nov 2001
    • 770

    #2
    If you are using a low res like 512x216 or 400x300 or a reduced framerate and the video dosen't contain a lot of motion/noise this could happen. Maybe 650MB allready gives the best possible DivX-quality. If you want a bigger filesize maybe you can use a higher res.
    don't trust in guides

    Comment

    • Gugus
      Junior Member
      Junior Member
      • Jul 2002
      • 7

      #3
      I'm using 640 X 480 of base resolution (after crop it change a little).
      I don't chage the framerate (25fps).

      And Stalingrad is a War film (with lot's of action).

      Comment

      • khp
        The Other
        • Nov 2001
        • 2161

        #4
        Try doing a 1-pass qualitybased encoding at 100%. If it comes out significantly larger than the files you produced, then something is wrong.

        Or if you can, try running the attached script, on the second pass logfile, the one called analyse.log, not the firstpass logfile.
        To run the script you will need to get the ActivePerl perl interpreter from www.activestate.com , place the file analyse.pl in the same directory as the analyse.log file, and double click analyse.pl.
        This will create a file called second_pass_stats.log, post this here.
        Attached Files
        Last edited by khp; 5 Nov 2002, 01:53 PM.
        Donate your idle CPU time for something usefull.
        http://folding.stanford.edu/

        Comment

        • Gugus
          Junior Member
          Junior Member
          • Jul 2002
          • 7

          #5
          Ok I download and will try it.
          Thanks

          Comment

          • Gugus
            Junior Member
            Junior Member
            • Jul 2002
            • 7

            #6
            Hi !
            Here is the log file.
            Where I could found documentation for understand this log file ?
            Attached Files

            Comment

            • khp
              The Other
              • Nov 2001
              • 2161

              #7
              Originally posted by Gugus
              Hi !
              Here is the log file.
              Great, the log file states that all frames were encoded using quantizer 2, which means that the movie is encoded at maximum quality, with the current settings. So unless you got some obvious defects in the video, I think you should be happy with this.

              But because B-frames are encoded with doubled quantizers, you might get better quality by encoding without B-frames, at the cost of a much bigger file of course.

              Originally posted by Gugus

              Where I could found documentation for understand this log file ?
              Nowhere !

              I'am sorry, it's just something I put together, trying to trackdown some undersizeing problems. Writeing documentation hasn't been a high priority for me.

              The file just states the total number of frames, and the total number of I-frames,P-frames, and B-frames.

              It then goes on to tell how many frames were encoded at each quantization level, for both I,P,B-frames and all of them combined.
              And of course also calculates the average quantizer.
              Last edited by khp; 11 Jul 2002, 07:41 AM.
              Donate your idle CPU time for something usefull.
              http://folding.stanford.edu/

              Comment

              • khp
                The Other
                • Nov 2001
                • 2161

                #8
                You can find an explanation of I,P, and B-frames here



                And quantizers are explained here



                and in many other threads in this forum, and http://forum.doom9.net, and http://forums.divx.com
                Donate your idle CPU time for something usefull.
                http://folding.stanford.edu/

                Comment

                • jagarus
                  Member
                  Member
                  • Apr 2002
                  • 73

                  #9
                  Whats FlaskMPEG XiS 3.0e?

                  Comment

                  • Gugus
                    Junior Member
                    Junior Member
                    • Jul 2002
                    • 7

                    #10
                    Thanks for your answer khp !
                    Jagarus, FlaskMEPG Xis 3.0e is a version witch support YV12 and YUY2 encoding.
                    You could found it here:

                    Comment

                    • Glanz
                      Super Member
                      Super Member
                      • Aug 2002
                      • 204

                      #11
                      ok i did the same thing here is my log file what can u tell me about it
                      i as well am getting bad quality on my movie i tried to reinstall divx 5.02 but that didnt work i put in a 2 cd size file and around 1200 kbps and it comes out around 400 mb and like 300 kbps which looks bad can u maybe help me
                      Attached Files

                      Comment

                      • khp
                        The Other
                        • Nov 2001
                        • 2161

                        #12
                        OK

                        This is very strange. According to the log, your file is nowhere near maximum quality, At maximum quality the file would probably be about 50%-70% larger (just a guess).

                        At the end of the analyse.log file there are two numbers marked progress and expected, could you post these. In the analyse log file these, numbers are noted for each frame, I'd like to know the numbers for the very last frame. This will tell us how close to the desired filesize the codec thought it was when it finished the movie.

                        To force the codec to produce higher quality you could do a quality based encoding at 100%. But of course you don't have any filesize prediction that way.
                        Donate your idle CPU time for something usefull.
                        http://folding.stanford.edu/

                        Comment

                        • Glanz
                          Super Member
                          Super Member
                          • Aug 2002
                          • 204

                          #13
                          i hope this is the right one
                          Attached Files

                          Comment

                          • Glanz
                            Super Member
                            Super Member
                            • Aug 2002
                            • 204

                            #14
                            how would i do a quality based encoding in gknot do u know what i mean ?

                            Comment

                            • khp
                              The Other
                              • Nov 2001
                              • 2161

                              #15
                              Dammit I missed something...

                              your encoding must be well an truely messedup.

                              The frame count is only 13107, only about 10 minutes of video.

                              Could it be that the first pass is aborted prematurely ?. Could you post you _GKnot.log file.

                              Could you try running the encoding in virtualdub manually. Load the avs file that GKnot created into virtualdub set video->fast recompression, and configure the codec in video->compression, you will have to set both the first and second pass manually.
                              Donate your idle CPU time for something usefull.
                              http://folding.stanford.edu/

                              Comment

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