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  1. Hi,
    I have an animated cartoon digitalized from PAL DIGIBETA tape onto the mov file with the ProRes 422HQ codec.
    It is an old cartoon called PEPA:

    The initial video bitrate is variable bitrate @24.5 Mbps. I need to recompess the file into h264 with the bitrate of 6-8 Mbps and wrapp in a mov container. I have used iFFMpeg, with the Force Constant Bitrate option enabled and the bitrate set to 8000. The output file only reaches about 2000kbps.

    I assume that the reason for such a low bitrate output is caused by the fact that the video file is not complex so the compresor is able to work very efficiently.

    Would anyone here have a solution to this problem? How to create a forced CBR H264 video in mov container?

    All the best!
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  2. Explorer Case's Avatar
    Join Date
    Feb 2004
    Middle Earth
    Search Comp PM
    Most home users want a small file. So the defaults may not suit what you need. But you may tweak the settings:
    Perhaps the Constant Quantizer wasn't set to OFF. Any setting other that OFF will disregard any bitrate settings, including CBR.
    Perhaps the Quantizer range wasn't broad enough to get to the desired high bitrate. (Tip: slide Qmin to "1" or "2".)
    These sliders can be found in Advanced > S4.
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  3. Hi Case,
    I have checked the settings which you are referring to and they are set as follow:
    I have also disabled b-frames.

    The output file comes out at about 2Mb/sec. When I check the output file in iMEdia HUD it says:

    The nominal bitrate is what I have set: 8Mb/sec but the bitrate value is only 1971 Kbps
    The VOD platform that I work for requires the files with a bitrate between 6-8 Mb/sec.

    HEre is the rundown of all the settings:
    Do you have any idea how to fix this?

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