What kind of routes could I get back from kAudioSe

问题:

Apple guy tried to be funny and wrote in the docs:

("Headphone," "Speaker," etc.)

What kind of return values are possible in reality?

回答1:

He wasn't being funny, those are actual values. The only one I've seen that he didn't outline is "LineOut"

回答2:

I ran 'strings' on the CoreMedia framework (iOS4.2 SDK), and the following strings seem reasonable and are grouped together:

• ReceiverAndMicrophone
• HeadsetInOut
• HeadphonesAndMicrophone
• SpeakerAndMicrophone
• HeadsetBT
• LineInOut
• Default

Command was:

strings -a -o CoreMedia | less

# CoreMedia is from /Developer/Platforms/iPhoneOS.platform/Developer \
# /SDKs/iPhoneOS4.2.sdk/System/Library/Frameworks/CoreMedia.framework

回答3:

According to http://lists.apple.com/archives/coreaudio-api/2009/Jan/msg00084.html there are also LineOut, HeadsetInOut, ReceiverAndMicrophone, HeadphonesAndMicrophone, but the guy who asked whether there are more values received no answer.

回答4:

I just got MicrophoneWired from it. (I actually have a special piece of hardware plugged in that is a temperature probe, but we are using it through the headphone jack).

Then I got MicrophoneBuiltIn with nothing plugged in. This is on an ipod touch with 4.3 by the way.

回答5:

The values provided by l8nite above are reserved for when your audio session is configured for both input and output. Other values used when you're only doing audio out: (I used the same trick as l8nite - thanks!)

LineOut

HeadphonesBT (used for Bluetooth audio output - observed this hooked up to via bluetooth to a car audio system)

AirTunes (used for AirPlay output)

回答6:

How is HeadphonesBT different from HeadsetBT ? My app could successfully use the HeadsetBT device to send and receive audio while HeadphonesBT failed to do anything. This is on iOs6