We can use Youtube as screencast to record Desktop Screen. It is free and we can directly post to Youtube.
1) Step 1: Sign-in to YouTube. Got to Creator Studio. Click events under Live Streaming in left panel.
2) Set video a title, Change video from public to private if you want to keep video private at the beginning, and click the “Go Live Now”
3) If this is the first time, you will be reminded to Install the Hangouts Plugin to get started. Click "install plugin" and run GoogleVioceAndVideoSetup.exe.
4) Click video icon to turn off webcam and unmute microphone if you want to record voice.
5) Click the Screenshare button, which is second icon in the left toolbox. If popup, select full screen in first. If you choose other options, you may not switch between different desktop windows.
6) click Start Broadcast to start recording the screen. After finish, click to stop Broadcast.
7) Go back Youtube Creator Studio, under Video manager, you can find the video you recorded. Change setting and publish in Youtube.
Compare to other screencast, I did not find pause button using this method,
Video:Use Youtube as screencast to record your Desktop Screen