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    40 ****************************************************************************/

    41 

    42 #include <QtMultimedia/QAudioFormat>

    43 #include "utils.h"

    44 

    45 qint64 audioDuration(const QAudioFormat &format, qint64 bytes)

    46 {

    47     return (bytes * 1000000) /

    48         (format.frequency() * format.channels() * (format.sampleSize() / 8));

    49 }

    50 

    51 qint64 audioLength(const QAudioFormat &format, qint64 microSeconds)

    52 {

    53    return (format.frequency() * format.channels() * (format.sampleSize() / 8))

    54        * microSeconds / 1000000;

    55 }

    56 

    57 qreal nyquistFrequency(const QAudioFormat &format)

    58 {

    59     return format.frequency() / 2;

    60 }

    61 

    62 QString formatToString(const QAudioFormat &format)

    63 {

    64     QString result;

    65 

    66     if (QAudioFormat() != format) {

    67         if (format.codec() == "audio/pcm") {

    68             Q_ASSERT(format.sampleType() == QAudioFormat::SignedInt);

    69 

    70             const QString formatEndian = (format.byteOrder() == QAudioFormat::LittleEndian)

    71                 ?   QString("LE") : QString("BE");

    72 

    73             QString formatType;

    74             switch(format.sampleType()) {

    75             case QAudioFormat::SignedInt:

    76                 formatType = "signed";

    77                 break;

    78             case QAudioFormat::UnSignedInt:

    79                 formatType = "unsigned";

    80                 break;

    81             case QAudioFormat::Float:

    82                 formatType = "float";

    83                 break;

    84             case QAudioFormat::Unknown:

    85                 formatType = "unknown";

    86                 break;

    87             }

    88 

    89             QString formatChannels = QString("%1 channels").arg(format.channels());

    90             switch (format.channels()) {

    91             case 1:

    92                 formatChannels = "mono";

    93                 break;

    94             case 2:

    95                 formatChannels = "stereo";

    96                 break;

    97             }

    98 

    99             result = QString("%1 Hz %2 bit %3 %4 %5")

   100                 .arg(format.frequency())

   101                 .arg(format.sampleSize())

   102                 .arg(formatType)

   103                 .arg(formatEndian)

   104                 .arg(formatChannels);

   105         } else {

   106             result = format.codec();

   107         }

   108     }

   109 

   110     return result;

   111 }

   112 

   113 bool isPCM(const QAudioFormat &format)

   114 {

   115     return (format.codec() == "audio/pcm");

   116 }

   117 

   118 

   119 bool isPCMS16LE(const QAudioFormat &format)

   120 {

   121     return (isPCM(format) &&

   122             format.sampleType() == QAudioFormat::SignedInt &&

   123             format.sampleSize() == 16 &&

   124             format.byteOrder() == QAudioFormat::LittleEndian);

   125 }

   126 

   127 const qint16  PCMS16MaxValue     =  32767;

   128 const quint16 PCMS16MaxAmplitude =  32768; // because minimum is -32768

   129 

   130 qreal pcmToReal(qint16 pcm)

   131 {

   132     return qreal(pcm) / PCMS16MaxAmplitude;

   133 }

   134 

   135 qint16 realToPcm(qreal real)

   136 {

   137     return real * PCMS16MaxValue;

   138 }