Mozillas Firefox 15 browser is now in beta, and Firefox 16 has hit the pre-beta Aurora channel.
Firefox 15, based on Gecko 15.0, will ship in August. According to Nicholas Nethercote, a programmer from Melbourne, Australia, who is working for Mozilla, Firefox 15 prevents most memory leaks caused by add-ons, including Firebug. For many users with add-ons installed, this will significantly reduce Firefoxs memory consumption, without requiring upgrades to those add-ons, he said.
For those users, Firefox 15 is likely to be faster (sometimes drastically so) and less likely to crash, especially if they have multiple add-ons installed and/or keep Firefox running for a long time between restarts, Nethercote said.
He notes that a memory leak occurs when a program allocates some memory but then fails to free it. There are multiple causes of memory leaks, but they all have the same effect: an increase in memory consumption, which often grows as the program runs. This can cause poor performance, and even lead to crashes or aborts due to the exhaustion of available memory, Nethercote said.
Firefox 15 also supports the Opus audio format, via the Opus reference implementation. Opus is a free audio format that was recently approved for publication as a standards-track Request for Comments (RFC) by the Internet Engineering Taskforce (IETF). Opus files can play in Firefox beta today.
In a blog post, Timothy Terriberry said Opus delivers better compression than MP3, Ogg, or AAC formats, is good for both music and speech, provides dynamically adjustable bit rate, audio bandwidth and coding delay, and has support for both interactive and prerecorded applications.
We think Opus is an incredible new format for Web audio, Terriberry said. Were working hard to convince other browsers to adopt it, to break the logjam over a common [audio] format. The codec is a collaboration between members of the IETF Internet Wideband Audio Codec working group, including Mozilla, Microsoft, Xiph.Org, Broadcom, Octasic, and others. We designed it for high-quality, interactive audio (VOIP, teleconference) and will use it in the upcoming WebRTC standard. Opus is also best-in-class for live streaming and static file playback. In fact, it is the first audio codec to be well-suited for both interactive and noninteractive applications.
Meanwhile, Firefox 16 has arrived in Mozillas pre-beta Aurora channel. In a blog post, Jean-Yves Perrier, a tech writer on the developer engagement team at Mozilla, said a major enhancement in Firefox 16 is the unprefixing of several stable CSS [Cascading Style Sheets] features. Other notable features of interest to Web developers include several more HTML5-related APIs, better accessibility on Mac OS, and improvements to Firefox Developer Tools.
The accessibility enhancement is support for VoiceOver on Mac OS, which was the last platform where Firefoxs accessibility features were severely behind, Terriberry said.