Mozilla has released a fifth Firefox 4 beta, offering graphics hardware acceleration on Windows and a new API that lets site developers code pages that visually display audio data inside the browser.

"The latest update to Firefox 4 Beta brings super fast graphics and incredible new audio capabilities to the Web," reads a blog post from Firefox development head Mike Beltzner.

The new beta also includes HTTP Strict Transport Security (HSTS), which lets websites demand that Firefox always use a secure connection when visiting. "Firefox 4 Beta now remembers what sites use the HSTS protocol and will only connect to those sites using SSL (Secure Sockets Layer) in the future, helping to prevent 'man in the middle' attacks," Beltzner says.

If you're running Windows Vista or Windows 7 and your graphics card is DirectX 10–compatible, Mozilla's beta will automatically accelerate graphics via Microsoft's Direct2D rendering system. Previously, the beta — and the Firefox 4 alpha — offered such hardware acceleration as an option, but it's now turned on by default.

In a separate post, Mozilla man Bas Schouten said that although there's nothing analogous to Direct2D from other OSes, Mozilla is also "working hard on alternative approaches to use hardware acceleration on other platforms."

The browser's new audio data API — dubbed Audio Data API — exposes raw audio data housed in HTML5's <audio> and <video> tags. With the API, coders can read and write audio data within the browser, building pages in Javascript that seek to turn a piece of sound into an animated graphic. "In December, a few of us...had an idea," reads a blog post from Seneca College professor and Mozilla contributor David Humphrey. "What if we could visualize sound data coming out of an <audio> or <video> element? My colleagues were good at thinking in terms of 'how can we make what we have now work?' But I had another idea: 'Let’s try and teach Firefox how to do this.'"

Clearly, this is the ideal tool for those looking to build an homage to late-60s psychedelia:

Last year, Mozilla began work on a project called ForceTLS that would allow sites to force a secure connection. "The main idea was simple, yet powerful: allow sites a way to say 'in the future, ALWAYS load me via HTTPS,'" said security maven Sid Stamm. The idea has now been added to the Firefox beta using the HTTP Strict Transport Security (HSTS) protocol.

"If Firefox knows your host is an HSTS one, it will automatically establish a secure connection to your server without even trying an insecure one," Stamm says in a new post. "This way, if I am surfing the 'net in my favorite cafe and a hacker is playing MITM [man in the middle] with paypal.com (intercepting http requests for paypal.com and then forwarding them on to the real site), either I'll thwart the attacker by getting an encrypted connection to paypal.com immediately, or the attack will be detected by HSTS and the connection won't work at all."

Stamm adds that work on the project is not completely finished. The team also aims to include an interface that lets you remove the HSTS default for a server on your own.

The Firefox 4 beta 5 can be downloaded here. And you can leave feedback here. A complete, stable version of Firefox 4 is scheduled for arrival in November. ®