def readData(self, maxlen): data = QByteArray() total = 0 while maxlen > total: chunk = min(self.m_buffer.size() - self.m_pos, maxlen - total) data.append(self.m_buffer.mid(self.m_pos, chunk)) self.m_pos = (self.m_pos + chunk) % self.m_buffer.size() total += chunk return data.data()
class Generator(QIODevice): def __init__(self, format, durationUs, sampleRate, parent): super(Generator, self).__init__(parent) self.m_pos = 0 self.m_buffer = QByteArray() self.generateData(format, durationUs, sampleRate) def start(self): self.open(QIODevice.ReadOnly) def stop(self): self.m_pos = 0 self.close() def generateData(self, format, durationUs, sampleRate): pack_format = '' if format.sampleSize() == 8: if format.sampleType() == QAudioFormat.UnSignedInt: scaler = lambda x: ((1.0 + x) / 2 * 255) pack_format = 'B' elif format.sampleType() == QAudioFormat.SignedInt: scaler = lambda x: x * 127 pack_format = 'b' elif format.sampleSize() == 16: if format.sampleType() == QAudioFormat.UnSignedInt: scaler = lambda x: (1.0 + x) / 2 * 65535 pack_format = '<H' if format.byteOrder( ) == QAudioFormat.LittleEndian else '>H' elif format.sampleType() == QAudioFormat.SignedInt: scaler = lambda x: x * 32767 pack_format = '<h' if format.byteOrder( ) == QAudioFormat.LittleEndian else '>h' assert (pack_format != '') channelBytes = format.sampleSize() // 8 sampleBytes = format.channelCount() * channelBytes length = (format.sampleRate() * format.channelCount() * (format.sampleSize() // 8)) * durationUs // 100000 self.m_buffer.clear() sampleIndex = 0 factor = 2 * pi * sampleRate / format.sampleRate() while length != 0: x = sin((sampleIndex % format.sampleRate()) * factor) packed = pack(pack_format, int(scaler(x))) for _ in range(format.channelCount()): self.m_buffer.append(packed) length -= channelBytes sampleIndex += 1 def readData(self, maxlen): data = QByteArray() total = 0 while maxlen > total: chunk = min(self.m_buffer.size() - self.m_pos, maxlen - total) data.append(self.m_buffer.mid(self.m_pos, chunk)) self.m_pos = (self.m_pos + chunk) % self.m_buffer.size() total += chunk return data.data() def writeData(self, data): return 0 def bytesAvailable(self): return self.m_buffer.size() + super(Generator, self).bytesAvailable()