There are several variables that affect file size. This article provides tips and general guidelines to help maximize your video and audio quality while minimizing the file size.
Video Encoding & File Size
Variable #1: Video Format
As a general rule of thumb, producing the video in MP4/h.264 format often delivers the best quality with smallest file size. MP4 is especially popular for web-based delivery. (AVI, MOV, or WMV can sometimes be good choices for CD or DVD delivery.) The default output from Camtasia Mac is MP4.
Variable #2: Video dimensions (in pixels)
Larger videos (in resolution) will dramatically increase file size. You may want to limit your video to no larger than 1280 pixels (width) by 720 (height). Don't record your entire screen unless it's really necessary, or consider using zoom and pan actions. This way you can scale the video down, but still focus the viewer's attention on a specific portion of the screen. Another tip is to reduce your screen resolution before recording your screen activity.
Video dimensions are set when you add video to the Timeline with the Edit->Project Settings option in Camtasia for Mac.
Variable #3: Amount of movement in the video
The more movement in the video, the larger the file size will be. For example, recording some fairly static presentation slides will yield a smaller file size than recording some on-screen live video. If possible, try not to drag windows around and limit some of the fancy animations in PowerPoint for example. Using the MP4 video format will also help mitigate some of the file size issues associated with movement, as MP4 is highly efficient in this regard.
Variable #4: Audio type
It is very rare that uncompressed audio is going to make an audible difference to your viewers. Therefore, you can reduce the file size dramatically by compressing the audio upon production. Unless you're featuring an orchestral masterpiece in your screencast, record mono audio, and after you're done editing, produce your video with compressed audio. Our default MP4 format uses AAC audio compression which has a good combination of sound quality and file size.
Variable #5: Frame rate
The frame rate indicates how many frames per second are shown to the viewer. The custom production settings allow for between 1 and 30 frames per second (fps). The default is 30 fps, which is good for live video, but for screen recordings 15 fps is typically more than adequate for most Camtasia users. If you're recording something fairly static, like a PowerPoint presentation you can drop the fps down which will save you a bit of file size and go virtually unnoticed to your viewers. Frame rate can be changed by going to Share>Local Files, Options.