Jaksta Media Recorder is well known as an all in one Pixiv Downloader, Pixiv Recorder and Pixiv Capture Tool and allows the downloading, recording and capturing of Video, Music and Radio.
Its easy to use Jaksta Media Recorder to record from Pixiv. Simply play Pixiv in your browser, and a copy of the Pixiv video is downloaded to your PC. You can also just drag and drop (or cut and paste) webpage urls containing videos directly from your browser and Jaksta Media Recorder will extact the video. Its as simple as that!
More detailed steps are available in the How to Download from Pixiv Guide