CamStudio

The information on this page was based around CamStudio version 2.5 beta 1.

What is CamStudio?

CamStudio is a free, open source screen recorder for Microsoft Windows. It is used for saving screen activity to an AVI file, with the option of having the AVI automatically converted into an SWF once the recording is finished.

Region

This determines which area of the screen will be recorded.

Region

With this option set, you have to select the recording area by drawing out a rectangle with the mouse cursor right after starting a new recording session.

Fixed Region
This allows you to use a rectangle at the given resolution and drag it over the area of the screen to be recorded. Checking "Fixed Top-Left Corner" will record from a set capture area as soon as you press record.

Fixed Top-Left Corner (left value must be at least 1)

An example setting for Center-Screen recording on 1024x768 monitor at 640x480 resolution might be:

Left = 200

Top = 110

Width = 640

Height = 480

Window

Records the region surrounding the selected window

Note that the capture will not follow the window if you move it after recording has started

Full Screen

Records the whole screen

A Note on Compression formats

If you plan on editing your recording later, using lossless codecs is recommended as quality will not decrease after multiple saves. A downside to this is lossless codecs will usually produce a larger file size then lossy codecs will, this may create problems if you do not have adequate storage space.

Video Options

the video options

Compressor:

Key Frames
- A lower Key Frames value will raise the overall file size after recording, but in contrast, setting the keyframe value too high may break seeking and lead to a reduction in video quality.
- note, the "Key Frames" setting here only works with certain codecs, some will bypass this setting entirely

Framerates:

Capture Frames Every __ milliseconds
Playback Rate

To get the Capture Frames value, divide 1000 (1 second = 1000 milliseconds) by the Playback Rate.

For example:

By default the playback rate is 20 and the Capture Every is 50, because 1000/20=50.
A playback rate of 10 would need the Capture Every set to 100, because 1000/10=100.
A playback rate of 25 would need the Capture Every set to 40, because 1000/25=40.
If you wanted a Playback Rate of 30 frames/second, a good capture rate would be 33, as 1000/30=33.333...

Four things to keep in mind:

A higher framerate will allow for smooth playback, but will also result in a larger file size as more frames will be created.
CamStudio currently only accepts whole numbers for the options here, any decimal values will simply be ignored (e.g.: if you entered 33.333 for your playback rate, CamStudio will store it as 33).
If you want to record video and audio at the same time, you will need to have values for the capture and playback rate with a product of exactly 1000 (e.g.: 100 for the capture frames and 10 for the playback as 100*10=1000). A capture frames value and playback rate that do not multiply wholly into 1000 (such as 33 and 30 mentioned in the example above) will cause the audio and video to become out of sync (33*30=990, not 1000).
A playback rate much higher than the capture setting is grabbing frames will "speed-up" or time-lapse the video, a lower playback rate will "slowdown" the playback rate

Auto Adjust:

You can use this to automatically set the "Capture Frames Every", "Playback Rate", and "Key Frames" by dragging the slider. This will attempt to adjust the 3 values for a "real-time" playback rate, but it will not always give ideal settings.

Audio Options

recording with audio

Audio Capture Device:

The computers sound card

Recording Format:

This is base recording format, for voice recording over a microphone, mono is usually fine

Compressed Format:

The format the audio will be compressed into when the recording is finished. You will want this set to an equal or lower quality to that of your recording format

Interleave Video and Audio:

Fixing Audio / Video Syncing Issues

Some things to try.

If the recording is unsynched by default, try:
- Options > Audio Options > Audio Options for Microphone > Use MCI Recording
  - Keep in mind this will override the chosen audio compression format

Pausing:
- There has been issues of audio video sync issues when using pause with certain configurations (I have not seen it myself using my config). The reported issue was a partial second delay at the point the recording was paused after the clip is saved. This causes the audio stream to get ahead of the video. At worst, if you insist on using pause, use it no more than one or two times within the recording. Another option would be to simply make multiple recordings and combine the clips (assuming they were recorded with the same settings) inside a video editor.

Make sure the "Capture Frames Every" and "Playback Rate" are set appropriately, see "Video Options" above

Testing audio video sync

A nice way to test if the audio and video are in sync is to record with an open a text editor (such as notepad) and type letters and numbers, voicing each key press into the microphone.

Recording to SWF

SWF is one of the Flash file formats making it compatible with many platforms. As mentioned above, CamStudio does not actually record directly to SWF, but instead records to an AVI file first and then converts the AVI into SWF once the recording is finished. The conversion isn't done with the CamStudio recorder, but with the included SWF producer.

With CamStudio 2.0 and 2.5, using the recorder's "Record to SWF" option will cause CamStudio to bypass the set video compressor option and record an AVI with the MS Video 1 codec before converting it to SWF.

Known Bugs and Limitations

Installation

"This application failed to start because MFC71.DLL was not found. Reinstalling the application may fix the problem."
- If you receive the above error message and reinstalling does not remedy the issue, try downloading MFC71.dll (found here http://www.camstudio.org/dev) and copying it into the folder where you have CamStudio 2.5 Beta installed (e.g.: "C:\Program Files\CamStudio\").
- If you still receive the above error message when launching CamStudio, you can try copying the MFC71.dll into your “C:\Windows\System32″ directory then rebooting your computer.

Region > Window

When using the "Region > Window" capture setting, the captured area will have 1 extra pixel added to the right and bottom of the capture area. For example, if the window was 960x720, the captured area would be 961x721. Although these extra lines can easily be cropped off, this may cause problems with certain video compressor codecs. A rough work around for this would be to set the window size to be 1 pixel smaller in width and height then that you desire to capture at (e.g., if you wanted 960x720, instead set the window size to 959x719).

SWF Producer

Similar to the "Region > Window" bug described above, the SWF Producer will also add an extra pixel to the width and height of videos being converted to SWF. A workaround is possible through the same means described above, reducing the dimensions to be 1 pixel less than the target resolution.

File Size

CamStudio currently cannot create avi files over 2GiB in size. Files over this size will likely be corrupted and difficult, if not impossible, to recover.

Keyboard Shortcuts

It is not currently possible to set just one keyboard shortcut to use with CamStudio. In order use the keyboard shortcuts, all of them must be set to different keys.

Many of these things are addressed here.

External Links

Wikipedia has related information at CamStudio

Where to Download