The fifth Firefox 4 beta makes some small feature changes to the in-development browser, bringing a new audio API to the table, revamping its menu, and turning on hardware acceleration by default. Available for Windows, Mac, and Linux, Firefox 4 beta 5 continues Mozilla's new beta release schedule, marked by more frequent releases and smaller feature revisions per update.

The most visual change to the beta is the redone menu in the Windows version, which returns a lot of functionality that had been missing from the menu in previous betas. The single-column menu has been replaced with a two-tiered, two-colored menu. The locally stored Help menu options have returned, and the add-ons menu is available in a tweaked color scheme as a secondary window again, too. Cut, copy, and paste have returned to the menu in icon-only form, and more of Firefox's feature managers, such as bookmarks, history, and the Options menu, have their previous access options restored.

The audio data API is an under-the-hood coding option that gives programmers the ability to "interact with sound...in all the creative ways that video and images allow," according to a blog post by Mozilla's director of Firefox, Mike Beltzner. The API will allow developers to expose raw audio data, display the data visual using the HTML5 < canvas > tag, calculate and visual demonstrate audio spectrum, apply audio filters, and other visual representations of the audio content.

The hardware acceleration that debuted in the previous beta has now been turned on by default, indicating Mozilla's confidence in its effectiveness. However, this is still a beta, so it's reasonable to expect further development tweaks to the hardware acceleration. Mozilla is tracking some buggy behavior that might be related to hardware acceleration.

Firefox 4 beta 5 also debuts support for an expansion of the HTTPS security feature. Called HTTP Strict Transport Security, or HSTS, it will force Firefox to use HTTPS. If the browser can't establish a secure connection, it won't resolve the URL even if there is an insecure connection available. It's a small change that could have big implications for accessing e-commerce and banking sites, for example.

A feature freeze had been planned for this beta, but it was pushed back to the sixth beta at the beginning of September. The changelog details a complete list of changes in Firefox 4 beta 5.