diff --git a/src/Tuner.cpp b/src/Tuner.cpp
index f4fe208..d043298 100644
--- a/src/Tuner.cpp
+++ b/src/Tuner.cpp
@@ -77,9 +77,13 @@ void Tuner::ComputeFrame(int16_t v)
 void Tuner::AudioCb(const QAudioBuffer &buffer)
 {
 	const int16_t *ptr = buffer.constData<int16_t>();
-	int nbFrame = buffer.sampleCount();
+	const int nbFrame = buffer.sampleCount();
+	AudioAnalyse(ptr, nbFrame);
+}
 
-	while (nbFrame--) ComputeFrame(*ptr++);
+void Tuner::AudioAnalyse(const int16_t *ptr, int nb_frame)
+{
+	while (nb_frame--) ComputeFrame(*ptr++);
 
 	if (freq != cross->Freq()) {
 		freq = cross->Freq();
@@ -129,7 +133,7 @@ int Tuner::GetOctave()
 	return octave;
 }
 
-QString Tuner::GetNoteName()
+const char* Tuner::GetNoteName()
 {
 	return scale->NoteName(note);
 }
diff --git a/src/Tuner.hpp b/src/Tuner.hpp
index e9196ba..a1548fc 100644
--- a/src/Tuner.hpp
+++ b/src/Tuner.hpp
@@ -44,13 +44,15 @@ class Tuner : public QObject {
 	void Start();
 	void Stop();
 
+	void AudioAnalyse(const int16_t *buffer, int size);
+
 	bool GetRunning();
 	void SetRunning(bool r);
 	double GetFreq();
 	int GetNote();
 	int GetOctave();
 	double GetDeviation();
-	QString GetNoteName();
+	const char* GetNoteName();
 
 	signals:
 	void runningChanged();
diff --git a/src/desktop.cpp b/src/desktop.cpp
index df0a65e..c36a7fe 100644
--- a/src/desktop.cpp
+++ b/src/desktop.cpp
@@ -2,10 +2,40 @@
 #include <QQuickView>
 #include <QtQml>
 
+#include <iostream>
+#include <fstream>
+
 #include "Tuner.hpp"
 
+static void analyse_file(const char *filename)
+{
+	using namespace std;
+	cout << "analyse file " << filename << endl;
+	ifstream fin;
+	fin.open(filename);
+
+	const int nb_frame = 1024;
+	Tuner *tuner = new Tuner();
+	int16_t buffer[nb_frame];
+
+	while (1) {
+		fin.read((char*) buffer, sizeof(buffer));
+		tuner->AudioAnalyse(buffer, sizeof(buffer) >> 1);
+
+		cout << tuner->GetFreq() << " " << tuner->GetNoteName() << " " << tuner->GetOctave() << endl;
+
+		if (fin.eof()) break;
+	}
+	delete tuner;
+}
+
 Q_DECL_EXPORT int main(int argc, char* argv[])
 {
+	if (argc == 2) {
+		analyse_file(argv[1]);
+		return 0;
+	}
+
 	qmlRegisterType<Tuner>("LJTuner", 1, 0, "Tuner");
 
 	QGuiApplication app(argc, argv);
diff --git a/src/scale/Scale.cpp b/src/scale/Scale.cpp
index de3f597..aeaaa32 100644
--- a/src/scale/Scale.cpp
+++ b/src/scale/Scale.cpp
@@ -62,7 +62,7 @@ int Scale::FindNote(double freq, int &octave, double &deviation)
 	int note = 0;
 	octave = findOctave(freq);
 
-	std::cerr << octave << "  " << freq << std::endl;
+	//std::cerr << octave << "  " << freq << std::endl;
 	assert(freq >= actualRange[0] && freq <= actualRange[1]);
 
 	while (actualNoteFreq[note] < freq && note < nbNote - 1) note++;