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Obtain Small Movie File Sizes With Camstudio Screen Recorder

edited June 2012 in Announcements
Here is a quick and dirty tutorial showing you guys how to obtain smaller/optimum file sizes for your videos created with Camstudio.

Video Length 6 min.

Hope you found this help full!


  • ForbiddenSoul,

    Not quite right, and looks awful as compressed as you've made it. Please watch my videos up top to get this right from the get-go.

  • Hi guys...

    Just a few opinions of my own, and those who use CamStudio should keep in mind that I do not use it to do tutorials and have no plans to do so in the future.

    First, MP3 does indeed work in Cam on 64 bit machines. That lame enc dll is a bear to register properly on Vista machines, but it can be done. If one needs to reduce file size (as with a very long tutorial, where the audio becomes disproportionately large in relation to the total file size) one should be doing it within the capture process to keep under the 2 GB limit. File size thereafter is rarely of any great concern. I made a quick test on my Vista and Win 7 computers and found that both have no problems with any sort of layer III, and the MP3 compression seems to be appropriate, from what I can tell. I would never use it, but it’s there, if need be.

    I don’t like doing bitrate calculations every time I open any sort of video program, and I subscribe to the theory that all MPEG 4 work should be done using the quantiser and that should always be set to 2. When one approaches 4, the quality suffers noticeably, and when one moves below (better than) 2, one reaches the point of diminishing returns and actually adversely affects video quality. (Too long a discussion for this thread). I do understand that this is a somewhat “dumbed down” approach, but it works.

    But here’s the deal as I see it. If that video had been made at 480, and a LOT more bitrate had been thrown at it, the result would have been much better, and the file size wouldn’t have been all that much larger. No, Youtube would not have stuck the HD label on it, and there would have been no 720 download option, but the video quality would have been much better. I’m getting annoyed at Youtube uploads which fool their software into thinking it’s HD, when it’s little more than a large-scale picture of a low-res image.

    I doubt seriously that using an “unrestricted” profile setting will ever have an adverse affect when copying what is basically as static screen, but those capturing high motion video should be aware that some constraints may be needed. I’m actually starting to be quite impressed with how well Youtube’s software is managing to deal with the hideous variety of codecs, containers, frame rates and audio we’re throwing at it.

    We may get this perfected before MPEG 4 goes the way of the Oldsmobile.

  • edited June 2012
    Thanks for your input guys!

    Watched some of your videos and they are all quite nice and informative, but I don't see any there for compressing the audio after recording. I understand the quality of my videos are not the best, but I was aiming for a smaller file size, not high def video. As explained in the tutorial you can increase the bitrate to increase the quality, i.e. you double the bitrate the quality will double as well as the video stream size.

    MP3 might indeed work, but not for me, and I imagine some other people, so I show how to compress it in mp3 format after the fact.

    I didn't mean for the bitrate calculations to be complicated I simply set it so that your video stream is ~1MB / minute (that's the same as the audio in my video). By all means use the quanitizer, or increase the bitrate for better quality.

    Using profile settings only changes the bitrate range you are allowed to select. The
    Xvid Mobile profile allows u to select a range of 16-1334kbps, while the Xvid HD 1080 pofile and the unrestricted profile both allow a range selection of 16-20480kbps, so you are correct they do not have an adverse affect on the video, just your bitrate selection.
  • I think that, in the real world, the issue has always been about how to get files small enough to keep Cam under the 2GB AVI 1 limits, so users can get longer videos without suffering a loss in quality. Terry’s using an HD 720 profile without overly compressed audio and seems to be able to produce tutorials of at least two and a half hours with very nice quality. I’m doing high motion video and can get about 35-40 minutes, with absolutely no hope of improving on that using MPEG 4, without significantly sacrificing quality. We’re right at the limits of what the codecs can do here.

    So, if substituting MP3 after the fact is an academic exercise, I guess it’s okay, but otherwise the only reason for using compressed audio here would be to effectively lengthen the recording time within a capture where the audio becomes disproportionately large, as in a very long screen tutorial, and I don’t think that’s a pressing need. Again, introducing MP3 after the fact, doesn’t alter the recording limits of the program, and we don’t otherwise need files that small. If we’re processing outside of Cam, I would suggest that Vdub might not necessarily be my first choice of programs to use, since it leaves us with a somewhat smaller file in the same AVI container with pretty hostile frame rates.

    Yes, all of the HD and ASP levels have a usable bitrate range, but what I’m suggesting (as subtly as possible) is that there are going to be more quality videos produced by more people, if we suggest that a practical quantizer setting be used. I’d never choke down the bitrate past levels that produce a good result, because I’d be afraid that people are going to see it and think it’s an okay thing to do, and it’s not. The codec can be pushed to extremes, but I’m afraid that going beyond those limits produces a bad result and earns an undeserved bad reputation for the program itself.

  • edited June 2012
    Thanks Ken,

    I made this tutorial, because I was using another screen capture software prior, freeze screen video capture, but my audio was always out of sync after about 3 minutes of recording. Switching over to camstudio remedied this, but using the exact same settings I was getting file sizes 3x larger for the same amount of time, and then determined it was due to my MP3 audio encoding not working within camstudio. The main point was to show you how to encode the audio stream to mp3 format after the fact.

    If you know how to get MP3 encoding working within camstudio that would be amazing!

    If you would like keep camstudio under the 2GB limit, you can always disable the audio recording within Camstudio, and use another audio recording program in conjunction with it, such as audacity or windows sound recorder, then add the audio stream to the video stream afterwords.

    Real easy to do within VirtualDub.
    Vido->Direct Stream copy
    Audio->Audio from other file...
  • edited June 2012

    You are quite correct - I have been very bad about getting my "CamStudio Audio" tutorial recorded and put out there! I've been promising one for months now!

    As Ken points out, I've been able to record amazingly long tutorial videos without going over the 2GB limit even using MCI to record (that's PCM, 16-bit, 44.1MHz if the checkbox isn't working, as has been the case for some recently). I use 1280X720 for HD, Jawor's Xvid with the 720HD profile, quality 1 (though 2 would probably suffice), Target Quantizer 1. However, my speed settings are very different from Ken's, as I am doing low-motion capture, so I use Capture Frames Every 100 ms and a Playback Rate of 10. Since very little changes between key frames, I only set keyframes every 200 frames (so it records an entire frame every 200 frames, and only records what changes frame-to-frame for the other 199 frames in between).

    I then either simply upload to YouTube and let them convert to MPEG-4 for me, or I use Any-Video-Converter to convert to MPEG-4 Custom.

    I convert to AC3 or AAC audio rather than MP3 because I've always experienced sync drift (where there was none before) when using MP3, but the AAC and AC3 audio codecs do not cause this to come up.

    I'll sit down and get out a video tonight when I can quite this room down for a while by shutting off the air conditioning!! :-)

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