[coco8] Recording Audio from Bluetooth mic

Set Audio Session

"Set current session for audio play and recording"
| session |
session := AVAudioSession sharedInstance.
session setCategory: #AVAudioSessionCategoryPlayAndRecord
	withOptions: 4 error: nil.
session	setMode: #AVAudioSessionModeDefault error: nil.
session setActive: true error: nil.

Get available audio inputs

| session inputs |
session := AVAudioSession sharedInstance.
inputs := (session availableInputs
 asArrayOf: AVAudioSessionPortDescription)
 collect: [:each| each portName -> each portType ].
inputs asLiteral

Get current audio source

| session port |
session := AVAudioSession sharedInstance.
port := (session currentRoute inputs
 asArrayOf: AVAudioSessionPortDescription) first
 "portType"portName
 toString

Initializing a recorder to save audio in a file

| url settings recorder pError pathName |
pError := # #outArgument.
pathName := '*record.m4a' asLocalPathName.
#audio outputToFile: pathName. "the destination file must exist"
url := NSURL withPath: pathName.
settings := #AVFormatIDKey -> 16r61616320 "'aac ' = kAudioFormatMPEG4AAC"
	,(#AVSampleRateKey -> 44100) "44100 Hz"
	,(#AVNumberOfChannelsKey -> 1)
	,(#AVEncoderAudioQualityKey -> 16r7F000002). "AVAudioQualityHigh"
recorder := AVAudioRecorder
	withURL: url
	settings: settings
	error: pError.

R := recorder.

• Note:
  1. The file MUST exist (and be writable) before recorder creation
  2. We use R global name to make the recorder available for the next chunks of code in this page

Prepare and start recoding

R prepareToRecord; record.

Stop recoding

R stop

Reading the audio contents

self note: 'Size of audio file =' ,'*record.m4a' fileContents size ,'bytes.' 

Clean the globals we have used in this page

 Smalltalk removeKey: #R ifAbsent: [].