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Camstudio 2.6 r294 does not compress the audio stream (always PCM)

I am using Camstudio since a lot of time, for recording my own lessons at the University, and later making them available to the students on my web site.
On several computers I installed the previous version, and everything worked OK, storing the video at 1024x768, 5 FPS, and the audio at 11 kHz, 16 bits, mono, with MP3 compression (2 kB/s).
Today I downloaded and installed the new version on a new computer. Albeit employing exactly the same settings outlined above, the audio comes out to be uncompressed: reopening the resulting AVI with VLC, the audio stream is said to be pure PCM at 11 kHz, 16 bits, mono, instead of being MP3...
And, of course, the file size is enormous...
I tested with several other available audio codecs, including Microsoft ADPCM, Ogg Vorbis and DivX WMA, but the result is always the same.
I am NOT setting CamStudio to use MCI recording.
My hypothesis is that on this computer some key component is missing, namely something such as an active-x plugin which allows to chain Camstudio with the audio codecs installed on the PC. On the other PC, during the compression, a "FFMPEG" icon was appearing in the status bar of the computer, near the clock, whilst on this computer nothing appears (and the audio stream is saved uncompressed).
What is exactly the missing component, and where can I download and install it?
And why isn't this component part of the standard setup of Camstudio?
Thanks in advance!


Angelo Farina


  • edited April 2011

    I wonder if it would help matters to re-install the Microsoft Visual C++ Runtimes from scratch?

    2008 version

    2010 version

    Let me know if that helps!

  • edited April 2011
    I did try installing the VC++ redistributables (the first was already installed, the second was not): the problem is still there.
    Furthermore, I installed this new Beta version also on my older computer, the one which is working correctly with Camstudio 2.00. Also on this computer, with the new Beta version of Camstudio the audio remains always PCM, whilst employing the older version of Camstudio the MPEG - Layer 3 codec is employed correctly.
    I notice also two other relevant differences:
    1) When exiting Camstudio and opening again, the old version still indicates, in the Audio Options for Microphone, that the recording should occur using the Mpeg-Layer 3 codec, at 11025, 16 bits, mono; the new version, instead, at reopening, is always reset to PCM, 22050, 16 bits, stereo! So it appears that the new version is NOT STORING the settings for the audio format correctly...
    2) With the old version, I was used to employ the very good video codec named "x264vfw - H.264/MPEG-4 AVC codec". This simply does not appear in the list of available codecs on the new Camstudio Beta...

    I do not know if this issue of not displaying the video codec has anything to do with the missing audio compression capabilities...

    Please note that the bugs are now confirmed on a completely different computer, which is still running without troubles the older Camstudio 2.00, alongside with the buggy 2.6 Beta. This means that my hypothesis of some "missing component" on the PC must now be definitely rejected.
  • afar,

    Yes, the different beta versions definitely display differing codecs, and I'm not certain anyone understands why that is.

    As to it not saving your settings, if you are in Vista or Windows 7, start the program by right-clicking and selecting "Run as an Administrator" - those operating systems will not allow the program to write the settings to the programs folder or registry unless you are running as an administrator. Try that and let me know if it helps.

    I recently did some tests of audio and they did compress ok using LAME MP3, so I'm not certain why you are always getting PCM unless it is related to not running CamStudio as an administrator, perhaps.

    I hope we can solve this!

  • Hi Terry,
    I did this test both in the windows XP and windows 7 64bit, it seems that both do not compress audio using the codec you selected, even the UI display the right audio codec, but when you open the output AVI to check the media info, they are always using the PCM for the audio part.
    For Win 7 you need to "Run as an Administrator" to make sure your settings can be saved after you exit the program.
    It's more like the output audio codec do not use the audio setting value at all.

    Wish it's helpful for you identify the problem.

  • BTW, the V2.0 is working for me in the same machine.
  • Fascinating...

    And this is in spite of "Use MCI to record" not being checked? The purpose of that is to force PCM/system audio. This is remarkable that none of the compression settings are working. I know that I had GSM in mono working in mine, as well as MSADPCM.

    You know, I wouldn't be a bit surprised if the codec IS being used, but that the header isn't being updated correctly to report the actual codec employed.

    I personally always use MCI to record, actually wanting PCM as it helps facilitate good sync, and with Xvid I still get good file sizes for pretty long videos. The only downside is that I have to then run it through Any Video Converter to convert it to MPEG-4 Custom so that it plays nicely on every media player out there.

  • I confirm the bug with camstudio 2.7 r316, save on exit checked, mci unchecked.
    The resulting video has always pcm audio no matter my choice of codec. The chosen sampling rate , bit width , mono/stereo are applied though.
    When I reopen Cstudio my audio choices are there, only not taken into account at capture time.
    This contributor writing in German
    also sees the problem.
    Any chance for a work-around? My little one wants to capture his game and can't handle virtualdub for audio post compression.
    - JF
  • Heck, I'll try to replicate that here on my end. Thanks for pointing that German post out for me again - I'll get back to you on this soon.

    Meanwhile, use MCI to record to be on the safe side.

    Frankly, I SERIOUSLY would not compress during the recording anyway - every attempt I've made except to use MSADPCM resulted in the audio and video drifting out of sync. Wav audio is the way to go (and I get up to 3 hours recording in Xvid codec at quality 1 using Capture Frames Every at 100 and Playback Rate at 10, which YouTube doesn't seem to mind.)

    What is he going to do with the game after recording it? YouTube likes that uncompressed audio. Sure, your time-length is shortened, but experiment with where you max out with a file-size approaching 2GB. If longer captures are desired, start the recording, pause the game, stop the recording and save it, and re-start a new recording.

    BTW - CamStudio has a feature that auto-stops the recording after a set number of seconds goes by. Once you establish what your upper limits are, set that up and you'll never go over.

  • Terry: for what it’s worth, I was entirely distracted by the subject of x264 vs Xvid in that German thread and forgot about the fact that the PCM issue had been brought up again. I had tried an experiment using the same layer 3 audio on both 2.0 and 2.6c and had come up with the same results that vopo and others have run into. With exactly the same settings on both, 2.0 works perfectly while 2.6c reverts to PCM every time. Furthermore, the MP3 settings are lost when the program is closed and re-opened.

    I do agree with you that MP3 is of questionable value for use with Cam, nonetheless it might be a bit frustrating for those who find themselves pushing a button that isn’t attached to anything, so to speak. This is most likely a problem which can be fixed with a minor tweak, and hopefully that will happen.

  • Ken and everyone,

    Definitely - I'm emailing Nick to notify the programmer to look into this.

    Thanks for pointing this out!

  • edited March 2013
    In the meantime (and Nick just wrote to verify the issue was now at the top of the list), has anyone tried MS ADPCM? CamStudio does not seem to be able to correctly implement LAME or other MP3 codecs, but ADPCM is great with voice recordings and in my tests it did not cause any loss of Audio/Video sync.

    Here is an article I wrote about it some time ago:

    Though I conclude that article saying I would use VirtualDub or some other tool to compress PCM audio as a post-production move before uploading to YouTube, I have stopped bothering with that step and simply upload the file with the PCM audio to YouTube, as it gives them better information to process in their own way.

    Their PREFERENCES for uploads are AAC-LC audio, MP4 video, but they are not picky. Still, for those doing conversions, they have a general purpose or "standard quality" and high-quality bit-rate table that you'll probably find useful here as relates to the video part:

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