For some time I’ve received a few reports about lightspark rais­ing the sys­tem vol­ume to 100% (and “killing ears”) when­ever a YouTube clip was started. It took some time for me to fig­ure out what was going on, since I was not able to repro­duce the issue on my sys­tem and of course the code was not will­ingly touch­ing the sys­tem volume.

It turns out that the issue was caused by the recently intro­duced “flat-volume” sup­port in PulseAu­dio. When flat vol­ume is enabled the vol­ume of a stream is absolute and not rel­a­tive to the sys­tem vol­ume. Since the default vol­ume in flash is 100% by spec then Lightspark was unwill­ingly set­ting the sys­tem vol­ume to an extremely high value, and I’m really sorry for that.

I’ve just com­mit­ted a fix in git mas­ter that should fix this prob­lem for good by prop­erly vir­tu­al­iz­ing the vol­ume seen by flash and scal­ing it by the sys­tem vol­ume. I hope this helps peo­ple with flat vol­ume enabled.