bool WavDecoder::Init()
{
DataStream* ds = m_ds;
::memset(&m_format,0,sizeof(m_format));
//LOG_DEBUG("init");
/// read shunks
while (!ds->Eof())
{
Byte chunk_name[4];
if (ds->Read(chunk_name,4)!=4) break;
UInt32 chunk_size = 0;
if (ds->Read(reinterpret_cast<Byte*>(&chunk_size),4)!=4) break;
//// "fmt "
if (::strncmp(reinterpret_cast<const char*>(chunk_name),"fmt ",4)==0)
{
//LOG_DEBUG("found chunk 'fmt '");
if (chunk_size<16) return false;
if (ds->Read(reinterpret_cast<Byte*>(&m_format),sizeof(m_format))!=sizeof(m_format)) return false;
//endian_fix(&m_format);
/// uncompressed PCM
if (m_format.compression_code!=1) return false;
if (m_format.num_channels!=1 && m_format.num_channels!=2) return false;
if (m_format.bits_per_sample!=8 && m_format.bits_per_sample!=16) return false;
if (m_format.num_channels == 1) {
if (m_format.bits_per_sample==8)
m_type = SAMPLE_TYPE_MONO_8;
else if (m_format.bits_per_sample==16)
m_type = SAMPLE_TYPE_MONO_16;
} else if (m_format.num_channels == 2) {
if (m_format.bits_per_sample==8)
m_type = SAMPLE_TYPE_STEREO_8;
else if (m_format.bits_per_sample==16)
m_type = SAMPLE_TYPE_STEREO_16;
}
m_freq = m_format.sample_rate;
assert(chunk_size>=UInt32(sizeof(m_format)));
m_ds->Seek(chunk_size-UInt32(sizeof(m_format)),F_SEEK_CURRENT);
}
/// "data"
else if (::strncmp(reinterpret_cast<const char*>(chunk_name),"data",4)==0)
{
//LOG_DEBUG("found chunk 'data'");
m_samples+=chunk_size/m_format.block_align;
assert(chunk_size<=std::numeric_limits<Int32>::max());
m_ds->Seek(chunk_size,F_SEEK_CURRENT);
}
/// another
else
{
LOG_DEBUG("skip shunk '"<<chunk_name[0]<<chunk_name[1]<<chunk_name[2]<<chunk_name[3]<<"' "<< chunk_size << " bytes");
assert(chunk_size<=std::numeric_limits<Int32>::max());
m_ds->Seek(chunk_size,F_SEEK_CURRENT);
}
}
m_ds->Seek(4+4+4,F_SEEK_BEGIN);
m_unreaded = 0;
return m_samples!=0 && m_type!=SAMPLE_TYPE_UNKNOWN && m_freq!=0;
}
void LoadBuffer() {
size = strm->Read(buffer,size);
readed = 0;
if (size==0 && strm->Eof())
eof = true;
}
