Apple Insider has spotted a a newly released patent filed by Apple back in late 2007 that shows volume controls that can be integrated into various Web browsers. Described as a way to control "audio signals which may or may not be welcomed by the user" the patent depicts a new panel that sits in the top, right-hand corner of a user's browser and allows per-site controls over incoming audio signals. There's also a mute button that can cut out just the sounds from the browser entirely while leaving sound from other desktop applications untouched.
According to the patent, the key goal is to add a volume control overlay over sites that do not provide it, as well as a system that will remember the user's preferences between browsing sessions. This would be useful in Flash-heavy sites where the controls may be hidden away, or entirely absent. It would also let users create custom sound profiles, so you could have YouTube videos on your computer at work always start out at a low volume level, or your Internet alarm clock site always play at 100 percent.
The patent also describes situations where users can create specific rules that will change how audio can be played back based on whatever other applications are running. So you could theoretically set it to mute all your browser audio only when you're listening to music in iTunes, or using an audio-centric application like Skype, then bring the sound back as soon as you're not getting audio output from those applications. Apple has done something similar on the iPhone by interrupting music when you're getting a phone call, or slightly lowering the volume on notification sounds when you're using other apps.
What makes this patent filing notable is that it's not just for Safari, and is listed as being applicable to multiple browsers, which means it could either be a part of an upcoming OS or as a standalone application. As the usual disclaimer goes though, patents are often filed for technologies that never make it to market.
Update: Several readers have pointed out that Windows Vista has had a similar feature since its release called Volume Mixer that lets you pick out the maximum volume level for each application. However it's worth noting that in Apple's proposed implementation, the user would be able to control it on a per-site basis.Apple Patent -- Web Browser Audio Controls