Updated chromaprint fingerprinting

Author: djthorpe

chromaprint.go

@@ -0,0 +1,22 @@
+package media
+
+import (
+	"io"
+)
+
+////////////////////////////////////////////////////////////////////////////////
+// TYPES
+
+// Chromaprint is a wrapper around the chromaprint library. Create a new
+// Chromaprint object by calling chromaprint.New(sample_rate, channels)
+type Chromaprint interface {
+	io.Closer
+
+	// Write sample data to the fingerprinter. Expects 16-bit signed integers
+	// and returns number of samples written
+	Write([]int16) (int64, error)
+
+	// Finish the fingerprinting, and compute the fingerprint, return as a
+	// string
+	Finish() (string, error)
+}

pkg/chromaprint/doc.go

@@ -0,0 +1,5 @@
+/*
+chromaprint provides bindings to the Chromaprint library, which is a
+library for extracting audio fingerprints.
+*/
+package chromaprint

pkg/chromaprint/fingerprint.go

@@ -0,0 +1,91 @@
+package chromaprint
+
+import (
+	"io"
+	"unsafe"
+
+	// Packages
+	"github.com/mutablelogic/go-media/sys/chromaprint"
+)
+
+////////////////////////////////////////////////////////////////////////////////
+// TYPES
+
+// Chromaprint is a wrapper around the chromaprint library. Create a new
+// Chromaprint object by calling New(rate,channels)
+type Chromaprint interface {
+	io.Closer
+
+	// Write sample data to the fingerprinter. Expects 16-bit signed integers
+	// and returns number of samples written
+	Write([]int16) (int64, error)
+
+	// Finish the fingerprinting, and compute the fingerprint, return as a
+	// string
+	Finish() (string, error)
+}
+
+type fingerprint struct {
+	n   int64
+	ctx *chromaprint.Context
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// LIFECYCLE
+
+// Create a new fingerprint context
+func New(rate, channels int) *fingerprint {
+	// Create a context
+	ctx := chromaprint.NewChromaprint(chromaprint.ALGORITHM_DEFAULT)
+	if ctx == nil {
+		return nil
+	}
+	// Start the fingerprinting
+	if err := ctx.Start(rate, channels); err != nil {
+		ctx.Free()
+		return nil
+	}
+	// Return success
+	return &fingerprint{0, ctx}
+}
+
+// Close the fingerprint to release resources
+func (fingerprint *fingerprint) Close() error {
+	// Free the context
+	if fingerprint.ctx != nil {
+		fingerprint.ctx.Free()
+	}
+
+	// Release resources
+	fingerprint.ctx = nil
+
+	// Return success
+	return nil
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// PUBLIC METHODS
+
+// Write 16-bit signed integers with little-endian format, and
+// return the total number of bytes written
+func (fingerprint *fingerprint) Write(data []int16) (int64, error) {
+	if fingerprint.ctx == nil {
+		return 0, io.ErrClosedPipe
+	}
+	if err := fingerprint.ctx.WritePtr(uintptr(unsafe.Pointer(&data[0])), len(data)); err != nil {
+		return 0, err
+	}
+	fingerprint.n += int64(len(data))
+	return fingerprint.n, nil
+}
+
+// Finish the fingerprinting, and compute the fingerprint, return as a string
+func (fingerprint *fingerprint) Finish() (string, error) {
+	if fingerprint.ctx == nil {
+		return "", io.ErrClosedPipe
+	}
+	if err := fingerprint.ctx.Finish(); err != nil {
+		return "", err
+	}
+	return fingerprint.ctx.GetFingerprint()
+}

pkg/chromaprint/fingerprint_test.go

@@ -0,0 +1,52 @@
+package chromaprint_test
+
+import (
+	"encoding/binary"
+	"io"
+	"os"
+	"testing"
+
+	"github.com/mutablelogic/go-media/pkg/chromaprint"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	// Test data
+	testData1 = "../../etc/test/s16le_22050_1ch_audio.raw"
+)
+
+func Test_fingerprint_000(t *testing.T) {
+	chromaprint.PrintVersion(os.Stderr)
+}
+
+func Test_fingerprint_001(t *testing.T) {
+	assert := assert.New(t)
+	fingerprint := chromaprint.New(22050, 1)
+	assert.NotNil(fingerprint)
+	assert.NoError(fingerprint.Close())
+}
+
+func Test_fingerprint_002(t *testing.T) {
+	assert := assert.New(t)
+	fingerprint := chromaprint.New(22050, 1)
+	assert.NotNil(fingerprint)
+
+	r, err := os.Open(testData1)
+	assert.NoError(err)
+	defer r.Close()
+
+	buf := make([]int16, 1024)
+	for {
+		if err := binary.Read(r, binary.LittleEndian, buf); err == io.EOF {
+			break
+		}
+		assert.NoError(err)
+		n, err := fingerprint.Write(buf)
+		assert.NoError(err)
+		assert.NotZero(n)
+	}
+	str, err := fingerprint.Finish()
+	assert.NoError(err)
+	assert.NotEmpty(str)
+	assert.NoError(fingerprint.Close())
+}