Evan recently shared shared a link to Bret Victor's CUSEC presentation (which is worth watching, but not what this post is about). In the (internal) thread, Ami Fischman mentioned that, in addition to being more reliable, Vimeo's HTML5 player allows the use of the playbackRate attribute to speed up playback without affecting its pitch (at least with the codecs used by Chrome). I'm a big fan of listening to podcasts at higher speeds (especially via Downcast, which supports up to 3x, though I haven't made my way that high yet), so the idea of being able to do this for any video was very appealing.

YouTube's HTML 5 player already makes use of this, but for those sites that don't, I've made a Chrome extension (source). It adds a context menu that allows you to control the playback rate for any <video> or <audio> element. Note that Chrome's audio implementation currently has a bug which may result in the 1.25 and 1.5 rates not working, but it should be fixed soon. Also, Vimeo turned out to the tricky, since it overlays other nodes on top of its <video> element, and buffers very slowly. Your best bet is to let the video buffer a bit, and then right-click just above the controller.

Bonus tip: If you are viewing a video in QuickTime Player (the QuickTime X version) and miss the old playback rate controls from the A/V Control palette, you can instead option-click on the fast-forward button to increase the speed.