1 files changed, 68 insertions, 0 deletions
diff --git a/examples/multimedia/spectrum/utils.cpp b/examples/multimedia/spectrum/utils.cpp
new file mode 100644
index 000000000..3b4146a51
--- /dev/null
+++ b/examples/multimedia/spectrum/utils.cpp
@@ -0,0 +1,68 @@
+// Copyright (C) 2017 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "utils.h"
+#include <QAudioFormat>
+
+qreal nyquistFrequency(const QAudioFormat &format)
+{
+    return format.sampleRate() / 2;
+}
+
+QString formatToString(const QAudioFormat &format)
+{
+    QString result;
+
+    if (QAudioFormat() != format) {
+
+        QString formatType;
+        switch (format.sampleFormat()) {
+        case QAudioFormat::UInt8:
+            formatType = "Unsigned8";
+            break;
+        case QAudioFormat::Int16:
+            formatType = "Signed16";
+            break;
+        case QAudioFormat::Int32:
+            formatType = "Signed32";
+            break;
+        case QAudioFormat::Float:
+            formatType = "Float";
+            break;
+        default:
+            formatType = "Unknown";
+            break;
+        }
+
+        QString formatChannels = QStringLiteral("%1 channels").arg(format.channelCount());
+        switch (format.channelCount()) {
+        case 1:
+            formatChannels = "mono";
+            break;
+        case 2:
+            formatChannels = "stereo";
+            break;
+        }
+
+        result = QStringLiteral("%1 Hz %2 bit %3 %4")
+                         .arg(format.sampleRate())
+                         .arg(format.bytesPerSample() * 8)
+                         .arg(formatType)
+                         .arg(formatChannels);
+    }
+
+    return result;
+}
+
+const qint16 PCMS16MaxValue = 32767;
+const quint16 PCMS16MaxAmplitude = 32768; // because minimum is -32768
+
+qreal pcmToReal(qint16 pcm)
+{
+    return qreal(pcm) / PCMS16MaxAmplitude;
+}
+
+qint16 realToPcm(qreal real)
+{
+    return real * PCMS16MaxValue;
+}