Allows synchronisation of 2 HTML5 video and audio streams even on different tabs. Just click the popup to scan each page and press the "Sync" button to generate sync buttons nest to the video/audio, then click them (preferably when both are paused at the right times) to synchronise. Press the "Flush" button to remove synchronisation. The streams will pause, play, change playback rate and seek together. You can check the Developer tools console for information.