osx mumble issues: high cpu usage and no echo cancellation

[chiem]

- high cpu usage

On my 15" i5 MBP, mumble hovers around 20% cpu usage when no voice activity is going on, even when not connected to a server.

I've noticed that if I turn off "Use ambient noise reduction" in System Preferences/Sound/Input, the cpu usage drops about 1/3 to around 14%. Still, this seems abnormally high, especially when mumble in win7 takes 2%.

- no echo cancellation

The echo cancellation option is greyed out for me. Am I missing something, or is this feature simply not enabled for macs ?

[mkrautz]

CPU usage is indeed a bit high. Mostly I think it's because both the OS X audio driver *and* Mumble are preprocessing in particular the input stream. (That's what Instruments tells me.) :-) Also, it seems like (at least on my MacBook Pro), that a lot of sample conversion is going on as well in the AppleHDAEngine driver.

The reason it's eating up CPU% even though you aren't connected to a server is this preprocessing work. The preprocessor is always running, whether you're connected to a server or not. Mostly, this is to feed data into the preprocessor's AGC (Automatic Gain Control) so that your voice is always leveled correctly.

As for echo cancellation, that's not currently supported in Mumble for Mac OS X.