Camstudio can make very high quality video captures. It is open source and free.
To make a top quality Camstudio video,
1) Download and install Lossless codec or use an appropriate codec.
You can see the codecs at Options >Video Options >Select codec and set a high quality.
2) Options >Autopan Speed >Use a high number.
3) Use a mic. Setting are Options >Audio Options >Audio options for microphone. When the settings are ideal, the sound will be good.
4) When making a video capture, you set the size with Region >Fixed Region. Here is where you want the target video size.
When you make a movie with Camstudio, the recording area will be highlighted and moves as you move the mouse. If you stay within 1-inch from the edge, the region will not move. If you move closer to the edge, the region will move and the scrolling of the page may look a little stuttered.
If you make Camstudio videos within the fixed regions and add all video degments into video editing software, they will look very professional. If you need to scroll throughout the page and move the region, make sure to do it very slow and the results will be satisfactory.