Add micgrab example

README.md

@@ -10,7 +10,11 @@
 
     go get -u github.com/gen2brain/aac-go
 
-### Example
+### Examples
+
+See [micgrab](https://github.com/gen2brain/aac-go/blob/master/examples/micgrab/micgrab.go) example.
+
+### Usage
 
 ```go
 package main

examples/micgrab/micgrab.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/gen2brain/aac-go"
+	"github.com/gen2brain/malgo"
+)
+
+func main() {
+	device := mal.NewDevice()
+
+	numChannels := 2
+	sampleRate := 48000
+
+	var capturedSampleCount uint32
+	pCapturedSamples := make([]byte, 0)
+
+	onRecvFrames := func(framecount uint32, pSamples []byte) {
+		sizeInBytes := device.SampleSizeInBytes(device.Format())
+		sampleCount := framecount * device.Channels() * sizeInBytes
+
+		newCapturedSampleCount := capturedSampleCount + sampleCount
+		pCapturedSamples = append(pCapturedSamples, pSamples...)
+		capturedSampleCount = newCapturedSampleCount
+	}
+
+	err := device.ContextInit(nil, mal.ContextConfig{})
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	defer device.ContextUninit()
+
+	config := device.ConfigInit(mal.FormatS16, uint32(numChannels), uint32(sampleRate), onRecvFrames, nil)
+
+	fmt.Println("Recording...")
+	err = device.Init(mal.Capture, nil, &config)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	err = device.Start()
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	fmt.Println("Press Enter to stop recording...")
+	fmt.Scanln()
+
+	device.Uninit()
+
+	fmt.Println("Encoding...")
+	buf := bytes.NewBuffer(make([]byte, 0))
+
+	opts := &aac.Options{}
+	opts.SampleRate = sampleRate
+	opts.NumChannels = numChannels
+
+	enc, err := aac.NewEncoder(buf, opts)
+	if err != nil {
+		panic(err)
+	}
+
+	reader := bytes.NewReader(pCapturedSamples)
+
+	err = enc.Encode(reader)
+	if err != nil {
+		panic(err)
+	}
+
+	err = enc.Close()
+	if err != nil {
+		panic(err)
+	}
+
+	err = ioutil.WriteFile("capture.aac", buf.Bytes(), 0644)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("Press Enter to quit...")
+	fmt.Scanln()
+
+	os.Exit(0)
+}