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How to create smaller file sizes

edited April 2009 in Support
Hi there,

First off, as a new user to Camstudio 2.5, I want to say how amazing it is. I really appreciate it.

I'm having some problem sorting out how to use the settings in video options. Since I want to reduce the file size as much as possible, I need to find the right settings. As I understand it, decreasing video quality and frame rate is important ways to accomplish this. With settings of quality=20 and 20/50/20 for the key frame rate, frame rate and playback rate, I find that the file size doesn't change much. It seems more dependent on which codec I choose. Of the handful I've tried, XviD seems best but still produces a file that is about 8-9 MB for a 5 minute video (640x480). Can this be reduced further?
Also, should I use the auto-adjust feature or not?

Any ideas welcome. My aim is to upload to youtube and also put some short videos on my website. Bigger videos may create some problems for my modest website server.



  • Well, as for me, I go the best results simply using a separate program to convert the output AVI to something else. It's the easiest way of getting file size down for me.

    Try "Super" as a free program for converting videos. Or "Total Video Converter" if you like the non free variety. :P
  • Thanks AT.

    I will look into the Super program, although it adds a second layer to the process which I would rather avoid if possible.

    But I'm still wondering what the optimal Camstudio settings should be to reduce file size.

  • edited April 2009

    From my testing the best way to get the absolutely smallest is to record using the highest quality settings possible and then transcode the video using SUPER, VirtualDub or another program into a smaller filesize.

    For YouTube XViD, DiVX or x.264 seems to produce good results - even better than the CamStudio Lossless codec in some cases.

    These settings seem to work well:

    and Torbjorn and I posted info about a standalone x.264 video codec that works with YouTube (although the compression settings need some experimentation)



    Nick :o)
  • Hi Nick,

    Thanks for the suggestions. Ideally, I would like to avoid having to use a second program like Super. The files don't have to be tiny, just more manageable if possible. Basically I was just trying to make sense of the settings available in the options menu. Should I keep it at auto-adjust and just use something in the middle? And where should the quality slider be placed?

    I don't know if you're aware but your first link it to apache's comment on this page, not to a settings discussion.

  • I've never used the auto adjust, so I can't say much about that. The settings in Camstudio I've used are the ones recommended in an old blog post at

    Set Key Frames every: 75
    Capture frames every: 66
    Playback rate: 15

    The quality slider I usually forget to adjust, so that is set at the default 70. Sometimes I remember to set it to 100, but I have not checked if there is any difference in quality.

    You can try the following:
    Install and use the x264-codec mentioned by Nick. Set the video settings in CS as explained above, and the x264-settings as follows:
    Single pass - bitrate.
    Average bitrate: Try somewhere between 500 and 1000.

    This video was recorded with those settings (quality at 100, bitrate set at 600):

    It is a fairly static video, and without audio, but the quality is good, and filesize at 2min/MB. For videos with more stuff happening and audio, the filesize will of course be larger.

    (The way I've done this is usually to record using a lossless codec like the MSU SCLC or Lagarith, and reencode the video in Virtualdub with x264. The reencoding part is, by the way, one of the things I explain in this video:, but if you get satisfactory results without reencoding, then don't worry about that.)
  • THe smaller you go the worse the video quality gets... There are advanced codecs like x264.exe over at doom9 you can download a plethora of GUI front ends that control how your video is Handled.

    My favorite of the many is Ripbot264 here is the link to an installer for it...
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