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50
51#include <QAudioFormat>
52#include "utils.h"
53
54qint64 audioDuration(const QAudioFormat &format, qint64 bytes)
55{
56 return (bytes * 1000000) /
57 (format.sampleRate() * format.channelCount() * (format.sampleSize() / 8));
58}
59
60qint64 audioLength(const QAudioFormat &format, qint64 microSeconds)
61{
62 qint64 result = (format.sampleRate() * format.channelCount() * (format.sampleSize() / 8))
63 * microSeconds / 1000000;
64 result -= result % (format.channelCount() * format.sampleSize());
65 return result;
66}
67
68qreal nyquistFrequency(const QAudioFormat &format)
69{
70 return format.sampleRate() / 2;
71}
72
73QString formatToString(const QAudioFormat &format)
74{
75 QString result;
76
77 if (QAudioFormat() != format) {
78 if (format.codec() == "audio/pcm") {
79 Q_ASSERT(format.sampleType() == QAudioFormat::SignedInt);
80
81 const QString formatEndian = (format.byteOrder() == QAudioFormat::LittleEndian)
82 ? QString("LE") : QString("BE");
83
84 QString formatType;
85 switch (format.sampleType()) {
86 case QAudioFormat::SignedInt:
87 formatType = "signed";
88 break;
89 case QAudioFormat::UnSignedInt:
90 formatType = "unsigned";
91 break;
92 case QAudioFormat::Float:
93 formatType = "float";
94 break;
95 case QAudioFormat::Unknown:
96 formatType = "unknown";
97 break;
98 }
99
100 QString formatChannels = QString("%1 channels").arg(a: format.channelCount());
101 switch (format.channelCount()) {
102 case 1:
103 formatChannels = "mono";
104 break;
105 case 2:
106 formatChannels = "stereo";
107 break;
108 }
109
110 result = QString("%1 Hz %2 bit %3 %4 %5")
111 .arg(a: format.sampleRate())
112 .arg(a: format.sampleSize())
113 .arg(a: formatType)
114 .arg(a: formatEndian)
115 .arg(a: formatChannels);
116 } else {
117 result = format.codec();
118 }
119 }
120
121 return result;
122}
123
124bool isPCM(const QAudioFormat &format)
125{
126 return (format.codec() == "audio/pcm");
127}
128
129
130bool isPCMS16LE(const QAudioFormat &format)
131{
132 return isPCM(format) &&
133 format.sampleType() == QAudioFormat::SignedInt &&
134 format.sampleSize() == 16 &&
135 format.byteOrder() == QAudioFormat::LittleEndian;
136}
137
138const qint16 PCMS16MaxValue = 32767;
139const quint16 PCMS16MaxAmplitude = 32768; // because minimum is -32768
140
141qreal pcmToReal(qint16 pcm)
142{
143 return qreal(pcm) / PCMS16MaxAmplitude;
144}
145
146qint16 realToPcm(qreal real)
147{
148 return real * PCMS16MaxValue;
149}
150

source code of qtmultimedia/examples/multimedia/spectrum/app/utils.cpp