utils/wxMMedia/sndadpcm.cpp

   1 #ifdef __GNUG__
   2 #pragma implementation "sndmulaw.h"
   3 #endif
   4
   5 #include "sndsnd.h"
   6 #include "sndfrmt.h"
   7 #include "sndadpcm.h"
   8 #include "adpcm/g72x.h"
   9
  10 wxSoundAdpcmCodec::wxSoundAdpcmCodec()
  11   : wxSoundCodec()
  12 {
  13   g72x_init_state(codec_state);
  14 }
  15
  16 wxSoundAdpcmCodec::~wxSoundAdpcmCodec()
  17 {
  18 }
  19
  20 int wxSoundAdpcmCodec::GetBits(int nbits)
  21 {
  22   unsigned int mask;
  23   int bits;
  24
  25   if (bits_waiting == 0)
  26     current_byte = m_in_sound->GetChar();
  27
  28   mask = (1 << nbits) - 1;
  29   bits = current_byte & mask;
  30   current_byte >>= nbits;
  31   return bits;
  32 }
  33
  34
  35 void wxSoundAdpcmCodec::Decode()
  36 {
  37   int smp;
  38   wxSoundDataFormat pref_frmt;
  39
  40   pref_frmt = GetPreferredFormat(0);
  41   if (!(m_io_format == pref_frmt))
  42     ChainCodecAfter(pref_frmt);
  43
  44   bits = GetBits(4);
  45   if (m_io_format.GetByteOrder() == wxSND_SAMPLE_LE) {
  46     while (!StreamOk()) {
  47       smp = g721_decoder(bits, AUDIO_ENCODING_LINEAR, codec_state);
  48       m_out_sound->PutChar(smp & 0x00ff);
  49       m_out_sound->PutChar((smp & 0xff00) >> 8);
  50       bits = GetBits(4);
  51     }
  52   } else {
  53     while (!StreamOk()) {
  54       smp = g721_decoder(bits, AUDIO_ENCODING_LINEAR, codec_state);
  55       m_out_sound->PutChar((smp & 0xff00) >> 8);
  56       m_out_sound->PutChar(smp & 0x00ff);
  57       bits = GetBits(4);
  58     }
  59   }
  60 }
  61
  62 void wxSoundMulawCodec::Encode()
  63 {
  64 }
  65
  66 size_t wxSoundMulawCodec::GetByteRate() const
  67 {
  68   return m_srate;
  69 }
  70
  71 wxSoundDataFormat wxSoundMulawCodec::GetPreferredFormat(int WXUNUSED(no)) const
  72 {
  73   wxSoundDataFormat format;
  74
  75   format.SetCodecNo(WXSOUND_PCM);
  76   format.SetSampleRate(m_srate);
  77   format.SetBps(16);
  78   format.SetChannels(1);
  79   format.SetSign(wxSND_SAMPLE_SIGNED);
  80 #ifdef USE_BE_MACH
  81   format.SetByteOrder(wxSND_SAMPLE_BE);
  82 #else
  83   format.SetByteOrder(wxSND_SAMPLE_LE);
  84 #endif
  85   return format;
  86 }