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50
51 #include "wavefilewriter.h"
52
53 struct chunk
54 {
55 char id[4];
56 quint32 size;
57 };
58
59 struct RIFFHeader
60 {
61 chunk descriptor; // "RIFF"
62 char type[4]; // "WAVE"
63 };
64
65 struct WAVEHeader
66 {
67 chunk descriptor;
68 quint16 audioFormat;
69 quint16 numChannels;
70 quint32 sampleRate;
71 quint32 byteRate;
72 quint16 blockAlign;
73 quint16 bitsPerSample;
74 };
75
76 struct DATAHeader
77 {
78 chunk descriptor;
79 };
80
81 struct CombinedHeader
82 {
83 RIFFHeader riff;
84 WAVEHeader wave;
85 DATAHeader data;
86 };
87 static const int HeaderLength = sizeof(CombinedHeader);
88
89
WaveFileWriter(QObject * parent)90 WaveFileWriter::WaveFileWriter(QObject *parent)
91 : QObject(parent)
92 , m_dataLength(0)
93 {
94 }
95
~WaveFileWriter()96 WaveFileWriter::~WaveFileWriter()
97 {
98 close();
99 }
100
open(const QString & fileName,const QAudioFormat & format)101 bool WaveFileWriter::open(const QString& fileName, const QAudioFormat& format)
102 {
103 if (file.isOpen())
104 return false; // file already open
105
106 if (format.codec() != "audio/pcm" || format.sampleType() != QAudioFormat::SignedInt)
107 return false; // data format is not supported
108
109 file.setFileName(fileName);
110 if (!file.open(QIODevice::WriteOnly))
111 return false; // unable to open file for writing
112
113 if (!writeHeader(format))
114 return false;
115
116 m_format = format;
117 return true;
118 }
119
write(const QAudioBuffer & buffer)120 bool WaveFileWriter::write(const QAudioBuffer &buffer)
121 {
122 if (buffer.format() != m_format)
123 return false; // buffer format has changed
124
125 qint64 written = file.write((const char *)buffer.constData(), buffer.byteCount());
126 m_dataLength += written;
127 return written == buffer.byteCount();
128 }
129
close()130 bool WaveFileWriter::close()
131 {
132 bool result = false;
133 if (file.isOpen()) {
134 Q_ASSERT(m_dataLength < INT_MAX);
135 result = writeDataLength();
136
137 m_dataLength = 0;
138 file.close();
139 }
140 return result;
141 }
142
writeHeader(const QAudioFormat & format)143 bool WaveFileWriter::writeHeader(const QAudioFormat &format)
144 {
145 // check if format is supported
146 if (format.byteOrder() == QAudioFormat::BigEndian || format.sampleType() != QAudioFormat::SignedInt)
147 return false;
148
149 CombinedHeader header;
150 memset(&header, 0, HeaderLength);
151
152 #ifndef Q_LITTLE_ENDIAN
153 // only implemented for LITTLE ENDIAN
154 return false;
155 #else
156 // RIFF header
157 memcpy(header.riff.descriptor.id, "RIFF", 4);
158 header.riff.descriptor.size = 0; // this will be updated with correct duration:
159 // m_dataLength + HeaderLength - 8
160 // WAVE header
161 memcpy(header.riff.type, "WAVE", 4);
162 memcpy(header.wave.descriptor.id, "fmt ", 4);
163 header.wave.descriptor.size = quint32(16);
164 header.wave.audioFormat = quint16(1);
165 header.wave.numChannels = quint16(format.channelCount());
166 header.wave.sampleRate = quint32(format.sampleRate());
167 header.wave.byteRate = quint32(format.sampleRate() * format.channelCount() * format.sampleSize() / 8);
168 header.wave.blockAlign = quint16(format.channelCount() * format.sampleSize() / 8);
169 header.wave.bitsPerSample = quint16(format.sampleSize());
170
171 // DATA header
172 memcpy(header.data.descriptor.id,"data", 4);
173 header.data.descriptor.size = 0; // this will be updated with correct data length: m_dataLength
174
175 return (file.write(reinterpret_cast<const char *>(&header), HeaderLength) == HeaderLength);
176 #endif
177 }
178
writeDataLength()179 bool WaveFileWriter::writeDataLength()
180 {
181 #ifndef Q_LITTLE_ENDIAN
182 // only implemented for LITTLE ENDIAN
183 return false;
184 #endif
185
186 if (file.isSequential())
187 return false;
188
189 // seek to RIFF header size, see header.riff.descriptor.size above
190 if (!file.seek(4))
191 return false;
192
193 quint32 length = m_dataLength + HeaderLength - 8;
194 if (file.write(reinterpret_cast<const char *>(&length), 4) != 4)
195 return false;
196
197 // seek to DATA header size, see header.data.descriptor.size above
198 if (!file.seek(40))
199 return false;
200
201 return file.write(reinterpret_cast<const char *>(&m_dataLength), 4) == 4;
202 }
203