GStreamer backend for audio decoder service.

Includes basic integration test.

Change-Id: I4c6d1dbefa1f27e107b3556a3d4da58811eeb122
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

src/gsttools/qgstutils.cpp

@@ -168,7 +168,7 @@ QSize QGstUtils::capsCorrectedResolution(const GstCaps *caps)
 }
 
 /*!
- *Returns audio format for caps.
+  Returns audio format for caps.
   If caps doesn't have a valid audio format, an empty QAudioFormat is returned.
 */
 
@@ -251,4 +251,66 @@ QAudioFormat QGstUtils::audioFormatForCaps(const GstCaps *caps)
     return format;
 }
 
+
+/*!
+  Returns audio format for a buffer.
+  If the buffer doesn't have a valid audio format, an empty QAudioFormat is returned.
+*/
+
+QAudioFormat QGstUtils::audioFormatForBuffer(GstBuffer *buffer)
+{
+    GstCaps* caps = gst_buffer_get_caps(buffer);
+    if (!caps)
+        return QAudioFormat();
+
+    QAudioFormat format = QGstUtils::audioFormatForCaps(caps);
+    gst_caps_unref(caps);
+    return format;
+}
+
+
+/*!
+  Builds GstCaps for an audio format.
+  Returns 0 if the audio format is not valid.
+  Caller must unref GstCaps.
+*/
+
+GstCaps *QGstUtils::capsForAudioFormat(QAudioFormat format)
+{
+    GstStructure *structure = 0;
+
+    if (format.isValid()) {
+        if (format.sampleType() == QAudioFormat::SignedInt || format.sampleType() == QAudioFormat::UnSignedInt) {
+            structure = gst_structure_new("audio/x-raw-int", NULL);
+        } else if (format.sampleType() == QAudioFormat::Float) {
+            structure = gst_structure_new("audio/x-raw-float", NULL);
+        }
+    }
+
+    GstCaps *caps = 0;
+
+    if (structure) {
+        gst_structure_set(structure, "rate", G_TYPE_INT, format.sampleRate(), NULL);
+        gst_structure_set(structure, "channels", G_TYPE_INT, format.channelCount(), NULL);
+        gst_structure_set(structure, "width", G_TYPE_INT, format.sampleSize(), NULL);
+        gst_structure_set(structure, "depth", G_TYPE_INT, format.sampleSize(), NULL);
+
+        if (format.byteOrder() == QAudioFormat::LittleEndian)
+            gst_structure_set(structure, "endianness", G_TYPE_INT, 1234, NULL);
+        else if (format.byteOrder() == QAudioFormat::BigEndian)
+            gst_structure_set(structure, "endianness", G_TYPE_INT, 4321, NULL);
+
+        if (format.sampleType() == QAudioFormat::SignedInt)
+            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, TRUE, NULL);
+        else if (format.sampleType() == QAudioFormat::UnSignedInt)
+            gst_structure_set(structure, "signed", G_TYPE_BOOLEAN, FALSE, NULL);
+
+        caps = gst_caps_new_empty();
+        Q_ASSERT(caps);
+        gst_caps_append_structure(caps, structure);
+    }
+
+    return caps;
+}
+
 QT_END_NAMESPACE

src/multimedia/gsttools_headers/qgstutils_p.h

@@ -69,6 +69,8 @@ namespace QGstUtils {
     QSize capsResolution(const GstCaps *caps);
     QSize capsCorrectedResolution(const GstCaps *caps);
     QAudioFormat audioFormatForCaps(const GstCaps *caps);
+    QAudioFormat audioFormatForBuffer(GstBuffer *buffer);
+    GstCaps *capsForAudioFormat(QAudioFormat format);
 }
 
 QT_END_NAMESPACE

src/plugins/gstreamer/audiodecoder/qgstreameraudiodecodercontrol.cpp

@@ -62,6 +62,7 @@ QGstreamerAudioDecoderControl::QGstreamerAudioDecoderControl(QGstreamerAudioDeco
     connect(m_session, SIGNAL(bufferReady()), this, SIGNAL(bufferReady()));
     connect(m_session, SIGNAL(error(int,QString)), this, SIGNAL(error(int,QString)));
     connect(m_session, SIGNAL(formatChanged(QAudioFormat)), this, SIGNAL(formatChanged(QAudioFormat)));
+    connect(m_session, SIGNAL(sourceChanged()), this, SIGNAL(sourceChanged()));
     connect(m_session, SIGNAL(stateChanged(QAudioDecoder::State)), this, SIGNAL(stateChanged(QAudioDecoder::State)));
 }
 

src/plugins/gstreamer/audiodecoder/qgstreameraudiodecodersession.cpp

@@ -54,9 +54,24 @@
 #include <QtCore/qdebug.h>
 #include <QtCore/qdir.h>
 #include <QtCore/qstandardpaths.h>
+#include <QtCore/qurl.h>
+
+#define MAX_BUFFERS_IN_QUEUE 5
 
 QT_BEGIN_NAMESPACE
 
+typedef enum {
+    GST_PLAY_FLAG_VIDEO         = 0x00000001,
+    GST_PLAY_FLAG_AUDIO         = 0x00000002,
+    GST_PLAY_FLAG_TEXT          = 0x00000004,
+    GST_PLAY_FLAG_VIS           = 0x00000008,
+    GST_PLAY_FLAG_SOFT_VOLUME   = 0x00000010,
+    GST_PLAY_FLAG_NATIVE_AUDIO  = 0x00000020,
+    GST_PLAY_FLAG_NATIVE_VIDEO  = 0x00000040,
+    GST_PLAY_FLAG_DOWNLOAD      = 0x00000080,
+    GST_PLAY_FLAG_BUFFERING     = 0x000000100
+} GstPlayFlags;
+
 QGstreamerAudioDecoderSession::QGstreamerAudioDecoderSession(QObject *parent)
     : QObject(parent),
      m_state(QAudioDecoder::StoppedState),
@@ -64,28 +79,67 @@ QGstreamerAudioDecoderSession::QGstreamerAudioDecoderSession(QObject *parent)
      m_busHelper(0),
      m_bus(0),
      m_playbin(0),
+     m_appSink(0),
 #if defined(HAVE_GST_APPSRC)
      m_appSrc(0),
 #endif
-     mDevice(0)
+     mDevice(0),
+     m_buffersAvailable(0)
 {
     // Default format
     mFormat.setChannels(2);
     mFormat.setSampleSize(16);
     mFormat.setFrequency(48000);
-    mFormat.setCodec("audio/x-raw");
+    mFormat.setCodec("audio/pcm");
     mFormat.setSampleType(QAudioFormat::UnSignedInt);
 
 
     // Create pipeline here
-#if 0
+    m_playbin = gst_element_factory_make("playbin2", NULL);
+
     if (m_playbin != 0) {
+
+        int flags = 0;
+        g_object_get(G_OBJECT(m_playbin), "flags", &flags, NULL);
+        // make sure not to use GST_PLAY_FLAG_NATIVE_AUDIO, it prevents audio format conversion
+        flags &= ~(GST_PLAY_FLAG_VIDEO | GST_PLAY_FLAG_NATIVE_VIDEO | GST_PLAY_FLAG_TEXT | GST_PLAY_FLAG_VIS | GST_PLAY_FLAG_NATIVE_AUDIO);
+        flags |= GST_PLAY_FLAG_AUDIO;
+        g_object_set(G_OBJECT(m_playbin), "flags", flags, NULL);
+
+        m_appSink = (GstAppSink*)gst_element_factory_make("appsink", NULL);
+        gst_object_ref(GST_OBJECT(m_appSink));
+
+        GstAppSinkCallbacks callbacks;
+        memset(&callbacks, 0, sizeof(callbacks));
+        callbacks.new_buffer = &new_buffer;
+        gst_app_sink_set_callbacks(m_appSink, &callbacks, this, NULL);
+        gst_app_sink_set_max_buffers(m_appSink, MAX_BUFFERS_IN_QUEUE);
+        gst_base_sink_set_sync(GST_BASE_SINK(m_appSink), FALSE);
+
+        GstElement *audioConvert = gst_element_factory_make("audioconvert", NULL);
+
+        GstElement *bin = gst_bin_new("audio-output-bin");
+        gst_bin_add(GST_BIN(bin), audioConvert);
+        gst_bin_add(GST_BIN(bin), GST_ELEMENT(m_appSink));
+        gst_element_link(audioConvert, GST_ELEMENT(m_appSink));
+
+        // add ghostpad
+        GstPad *pad = gst_element_get_static_pad(audioConvert, "sink");
+        Q_ASSERT(pad);
+        gst_element_add_pad(GST_ELEMENT(bin), gst_ghost_pad_new("sink", pad));
+        gst_object_unref(GST_OBJECT(pad));
+
         // Sort out messages
         m_bus = gst_element_get_bus(m_playbin);
         m_busHelper = new QGstreamerBusHelper(m_bus, this);
         m_busHelper->installMessageFilter(this);
+
+        g_object_set(G_OBJECT(m_playbin), "audio-sink", bin, NULL);
+
+        // Set volume to 100%
+        gdouble volume = 1.0;
+        g_object_set(G_OBJECT(m_playbin), "volume", volume, NULL);
     }
-#endif
 }
 
 QGstreamerAudioDecoderSession::~QGstreamerAudioDecoderSession()
@@ -96,6 +150,7 @@ QGstreamerAudioDecoderSession::~QGstreamerAudioDecoderSession()
         delete m_busHelper;
         gst_object_unref(GST_OBJECT(m_bus));
         gst_object_unref(GST_OBJECT(m_playbin));
+        gst_object_unref(GST_OBJECT(m_appSink));
     }
 }
 
@@ -116,66 +171,6 @@ void QGstreamerAudioDecoderSession::configureAppSrcElement(GObject* object, GObj
 }
 #endif
 
-#if 0
-void QGstreamerAudioDecoderSession::loadFromStream(const QNetworkRequest &request, QIODevice *appSrcStream)
-{
-#if defined(HAVE_GST_APPSRC)
-#ifdef DEBUG_PLAYBIN
-    qDebug() << Q_FUNC_INFO;
-#endif
-    m_request = request;
-    m_duration = -1;
-    m_lastPosition = 0;
-    m_haveQueueElement = false;
-
-    if (m_appSrc)
-        m_appSrc->deleteLater();
-    m_appSrc = new QGstAppSrc(this);
-    m_appSrc->setStream(appSrcStream);
-
-    if (m_playbin) {
-        m_tags.clear();
-        emit tagsChanged();
-
-        g_signal_connect(G_OBJECT(m_playbin), "deep-notify::source", (GCallback) &QGstreamerAudioDecoderSession::configureAppSrcElement, (gpointer)this);
-        g_object_set(G_OBJECT(m_playbin), "uri", "appsrc://", NULL);
-
-        if (!m_streamTypes.isEmpty()) {
-            m_streamProperties.clear();
-            m_streamTypes.clear();
-
-            emit streamsChanged();
-        }
-    }
-#endif
-}
-
-void QGstreamerAudioDecoderSession::loadFromUri(const QNetworkRequest &request)
-{
-#ifdef DEBUG_PLAYBIN
-    qDebug() << Q_FUNC_INFO << request.url();
-#endif
-    m_request = request;
-    m_duration = -1;
-    m_lastPosition = 0;
-    m_haveQueueElement = false;
-
-    if (m_playbin) {
-        m_tags.clear();
-        emit tagsChanged();
-
-        g_object_set(G_OBJECT(m_playbin), "uri", m_request.url().toEncoded().constData(), NULL);
-
-        if (!m_streamTypes.isEmpty()) {
-            m_streamProperties.clear();
-            m_streamTypes.clear();
-
-            emit streamsChanged();
-        }
-    }
-}
-#endif
-
 bool QGstreamerAudioDecoderSession::processBusMessage(const QGstreamerMessage &message)
 {
     GstMessage* gm = message.rawMessage();
@@ -320,7 +315,10 @@ void QGstreamerAudioDecoderSession::setSourceFilename(const QString &fileName)
 {
     stop();
     mDevice = 0;
+    bool isSignalRequired = (mSource != fileName);
     mSource = fileName;
+    if (isSignalRequired)
+        emit sourceChanged();
 }
 
 QIODevice *QGstreamerAudioDecoderSession::sourceDevice() const
@@ -332,17 +330,71 @@ void QGstreamerAudioDecoderSession::setSourceDevice(QIODevice *device)
 {
     stop();
     mSource.clear();
+    bool isSignalRequired = (mDevice != device);
     mDevice = device;
+    if (isSignalRequired)
+        emit sourceChanged();
 }
 
 void QGstreamerAudioDecoderSession::start()
 {
-    // TODO
+    if (!m_playbin) {
+        processInvalidMedia(QAudioDecoder::ResourceError, "Playbin element is not valid");
+        return;
+    }
+
+    if (!mSource.isEmpty()) {
+        g_object_set(G_OBJECT(m_playbin), "uri", QUrl::fromLocalFile(mSource).toEncoded().constData(), NULL);
+    } else if (mDevice) {
+        // make sure we can read from device
+        if (!mDevice->isOpen() || !mDevice->isReadable()) {
+            processInvalidMedia(QAudioDecoder::AccessDeniedError, "Unable to read from specified device");
+            return;
+        }
+
+        if (m_appSrc)
+            m_appSrc->deleteLater();
+        m_appSrc = new QGstAppSrc(this);
+        m_appSrc->setStream(mDevice);
+
+        g_signal_connect(G_OBJECT(m_playbin), "deep-notify::source", (GCallback) &QGstreamerAudioDecoderSession::configureAppSrcElement, (gpointer)this);
+        g_object_set(G_OBJECT(m_playbin), "uri", "appsrc://", NULL);
+    } else {
+        return;
+    }
+
+    // Set audio format
+    if (m_appSink) {
+        GstCaps *caps = QGstUtils::capsForAudioFormat(mFormat);
+        gst_app_sink_set_caps(m_appSink, caps); // appsink unrefs caps
+    }
+
+    m_pendingState = QAudioDecoder::DecodingState;
+    if (gst_element_set_state(m_playbin, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+        qWarning() << "GStreamer; Unable to start decoding process";
+        m_pendingState = m_state = QAudioDecoder::StoppedState;
+
+        emit stateChanged(m_state);
+    }
 }
 
 void QGstreamerAudioDecoderSession::stop()
 {
-    // TODO
+    if (m_playbin) {
+        gst_element_set_state(m_playbin, GST_STATE_NULL);
+
+        QAudioDecoder::State oldState = m_state;
+        m_pendingState = m_state = QAudioDecoder::StoppedState;
+
+        // GStreamer thread is stopped. Can safely access m_buffersAvailable
+        if (m_buffersAvailable != 0) {
+            m_buffersAvailable = 0;
+            emit bufferAvailableChanged(false);
+        }
+
+        if (oldState != m_state)
+            emit stateChanged(m_state);
+    }
 }
 
 QAudioFormat QGstreamerAudioDecoderSession::audioFormat() const
@@ -360,15 +412,43 @@ void QGstreamerAudioDecoderSession::setAudioFormat(const QAudioFormat &format)
 
 QAudioBuffer QGstreamerAudioDecoderSession::read(bool *ok)
 {
-    // TODO
+    QAudioBuffer audioBuffer;
+
+    int buffersAvailable;
+    {
+        QMutexLocker locker(&m_buffersMutex);
+        buffersAvailable = m_buffersAvailable;
+
+        // need to decrement before pulling a buffer
+        // to make sure assert in QGstreamerAudioDecoderSession::new_buffer works
+        m_buffersAvailable--;
+    }
+
+
+    if (buffersAvailable) {
+        if (buffersAvailable == 1)
+            emit bufferAvailableChanged(false);
+
+        GstBuffer *buffer = gst_app_sink_pull_buffer(m_appSink);
+
+        QAudioFormat format = QGstUtils::audioFormatForBuffer(buffer);
+        if (format.isValid()) {
+            // XXX At the moment we have to copy data from GstBuffer into QAudioBuffer.
+            // We could improve performance by implementing QAbstractAudioBuffer for GstBuffer.
+            audioBuffer = QAudioBuffer(QByteArray((const char*)buffer->data, buffer->size), format);
+        }
+        gst_buffer_unref(buffer);
+    }
+
     if (ok)
-        *ok = false;
+        *ok = audioBuffer.isValid();
-    return QAudioBuffer();
+    return audioBuffer;
 }
 
 bool QGstreamerAudioDecoderSession::bufferAvailable() const
 {
-    return false;
+    QMutexLocker locker(&m_buffersMutex);
+    return m_buffersAvailable;
 }
 
 void QGstreamerAudioDecoderSession::processInvalidMedia(QAudioDecoder::Error errorCode, const QString& errorString)
@@ -377,4 +457,23 @@ void QGstreamerAudioDecoderSession::processInvalidMedia(QAudioDecoder::Error err
     emit error(int(errorCode), errorString);
 }
 
+GstFlowReturn QGstreamerAudioDecoderSession::new_buffer(GstAppSink *, gpointer user_data)
+{
+    // "Note that the preroll buffer will also be returned as the first buffer when calling gst_app_sink_pull_buffer()."
+    QGstreamerAudioDecoderSession *session = reinterpret_cast<QGstreamerAudioDecoderSession*>(user_data);
+
+    int buffersAvailable;
+    {
+        QMutexLocker locker(&session->m_buffersMutex);
+        buffersAvailable = session->m_buffersAvailable;
+        session->m_buffersAvailable++;
+        Q_ASSERT(session->m_buffersAvailable <= MAX_BUFFERS_IN_QUEUE);
+    }
+
+    if (!buffersAvailable)
+        QMetaObject::invokeMethod(session, "bufferAvailableChanged", Qt::QueuedConnection, Q_ARG(bool, true));
+    QMetaObject::invokeMethod(session, "bufferReady", Qt::QueuedConnection);
+    return GST_FLOW_OK;
+}
+
 QT_END_NAMESPACE

src/plugins/gstreamer/audiodecoder/qgstreameraudiodecodersession.h

@@ -43,6 +43,7 @@
 #define QGSTREAMERPLAYERSESSION_H
 
 #include <QObject>
+#include <QtCore/qmutex.h>
 #include "qgstreameraudiodecodercontrol.h"
 #include <private/qgstreamerbushelper_p.h>
 #include <private/qaudiodecoder_p.h>
@@ -52,6 +53,7 @@
 #endif
 
 #include <gst/gst.h>
+#include <gst/app/gstappsink.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -95,9 +97,12 @@ public:
     QAudioBuffer read(bool *ok);
     bool bufferAvailable() const;
 
+    static GstFlowReturn new_buffer(GstAppSink *sink, gpointer user_data);
+
 signals:
     void stateChanged(QAudioDecoder::State newState);
     void formatChanged(const QAudioFormat &format);
+    void sourceChanged();
 
     void error(int error, const QString &errorString);
 
@@ -110,9 +115,10 @@ private:
 
     QAudioDecoder::State m_state;
     QAudioDecoder::State m_pendingState;
-    QGstreamerBusHelper* m_busHelper;
+    QGstreamerBusHelper *m_busHelper;
-    GstBus* m_bus;
+    GstBus *m_bus;
-    GstElement* m_playbin;
+    GstElement *m_playbin;
+    GstAppSink *m_appSink;
 
 #if defined(HAVE_GST_APPSRC)
     QGstAppSrc *m_appSrc;
@@ -121,6 +127,9 @@ private:
     QString mSource;
     QIODevice *mDevice; // QWeakPointer perhaps
     QAudioFormat mFormat;
+
+    mutable QMutex m_buffersMutex;
+    int m_buffersAvailable;
 };
 
 QT_END_NAMESPACE

tests/auto/integration/qaudiodecoderbackend/qaudiodecoderbackend.pro

@@ -0,0 +1,15 @@
+TARGET = tst_qaudiodecoderbackend
+
+QT += multimedia multimedia-private testlib
+CONFIG += no_private_qt_headers_warning
+
+# This is more of a system test
+# CONFIG += testcase
+
+INCLUDEPATH += \
+    ../../../../src/multimedia/audio
+
+DEFINES += TESTDATA_DIR=\\\"$$PWD/\\\"
+
+SOURCES += \
+    tst_qaudiodecoderbackend.cpp

tests/auto/integration/qaudiodecoderbackend/tst_qaudiodecoderbackend.cpp

@@ -0,0 +1,151 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtTest/QtTest>
+#include <QDebug>
+#include "qaudiodecoder_p.h"
+
+#define TEST_FILE_NAME "testdata/test.wav"
+
+QT_USE_NAMESPACE
+
+/*
+ This is the backend conformance test.
+
+ Since it relies on platform media framework and sound hardware
+ it may be less stable.
+*/
+
+class tst_QAudioDecoderBackend : public QObject
+{
+    Q_OBJECT
+public slots:
+    void init();
+    void cleanup();
+    void initTestCase();
+
+private slots:
+    void decoderTest();
+};
+
+void tst_QAudioDecoderBackend::init()
+{
+}
+
+void tst_QAudioDecoderBackend::initTestCase()
+{
+}
+
+void tst_QAudioDecoderBackend::cleanup()
+{
+}
+
+void tst_QAudioDecoderBackend::decoderTest()
+{
+    QAudioDecoder d;
+    QVERIFY(d.state() == QAudioDecoder::StoppedState);
+    QVERIFY(d.bufferAvailable() == false);
+    QCOMPARE(d.sourceFilename(), QString(""));
+
+    // Test local file
+    QFileInfo fileInfo(QFINDTESTDATA(TEST_FILE_NAME));
+    d.setSourceFilename(fileInfo.absoluteFilePath());
+    QVERIFY(d.state() == QAudioDecoder::StoppedState);
+    QVERIFY(!d.bufferAvailable());
+    QCOMPARE(d.sourceFilename(), fileInfo.absoluteFilePath());
+
+    QSignalSpy readySpy(&d, SIGNAL(bufferReady()));
+    QSignalSpy bufferChangedSpy(&d, SIGNAL(bufferAvailableChanged(bool)));
+    QSignalSpy errorSpy(&d, SIGNAL(error(QAudioDecoder::Error)));
+    QSignalSpy stateSpy(&d, SIGNAL(stateChanged(QAudioDecoder::State)));
+
+    d.start();
+    QTRY_VERIFY(!stateSpy.isEmpty());
+    QTRY_VERIFY(!readySpy.isEmpty());
+    QTRY_VERIFY(!bufferChangedSpy.isEmpty());
+    QVERIFY(d.bufferAvailable());
+
+    bool ok;
+    QAudioBuffer buffer = d.read(&ok);
+    QVERIFY(ok);
+    QVERIFY(buffer.isValid());
+    QCOMPARE(buffer.format(), d.audioFormat());
+
+    QVERIFY(errorSpy.isEmpty());
+
+    d.stop();
+    QTRY_COMPARE(d.state(), QAudioDecoder::StoppedState);
+    QVERIFY(!d.bufferAvailable());
+    readySpy.clear();
+    bufferChangedSpy.clear();
+    stateSpy.clear();
+
+    // Test source device
+    QFile file(fileInfo.absoluteFilePath());
+    QVERIFY(file.open(QIODevice::ReadOnly));
+    d.setSourceDevice(&file);
+
+    // change output audio format
+    QAudioFormat format;
+    format.setChannels(1);
+    format.setSampleSize(8);
+    format.setFrequency(8000);
+    format.setCodec("audio/pcm");
+    format.setSampleType(QAudioFormat::SignedInt);
+    d.setAudioFormat(format);
+
+    d.start();
+    QTRY_VERIFY(!stateSpy.isEmpty());
+    QTRY_VERIFY(!readySpy.isEmpty());
+    QTRY_VERIFY(!bufferChangedSpy.isEmpty());
+    QVERIFY(d.bufferAvailable());
+
+    buffer = d.read(&ok);
+    QVERIFY(ok);
+    QVERIFY(buffer.isValid());
+    QCOMPARE(buffer.format(), d.audioFormat());
+
+    QVERIFY(errorSpy.isEmpty());
+}
+
+QTEST_MAIN(tst_QAudioDecoderBackend)
+
+#include "tst_qaudiodecoderbackend.moc"