audiowrap.c

本程序为ST公司开发的源代码

  data = C2FlagsVect[3] + (C2FlagsVect[4] << 8) + (C2FlagsVect[5] << 16); // # 5 4 3
  data <<= 8; // 5 4 3 #

  if(C2_flags_in_idx != 643)
    data |= ((data_3>>24)&0xFF);

  out_ptr[C2_flags_out_idx] = data;

  C2_flags_out_idx += 7;



  data_3 = in_ptr[SubCode_idx++];



  data = C2FlagsVect[6] + (C2FlagsVect[7] << 8) + (C2FlagsVect[8] << 16); // # 8 7 6
  data <<= 8; // 8 7 6 #

  data |= (data_3&0xFF);

  out_ptr[C2_flags_out_idx] = data;

  C2_flags_out_idx += 7;

  data = C2FlagsVect[9] + (C2FlagsVect[10] << 8) + (C2FlagsVect[11] << 16); // # 11 10 9
  data <<= 8; // 11 10 9 #

  data |= ((data_3>>8)&0xFF);

  out_ptr[C2_flags_out_idx] = data;

  C2_flags_out_idx += 7;
 }

  //C2_flags_in_idx : 712
  //C2_flags_out_idx: 673 4*24=96
  //SubCode_idx:      616 616*4=2464

 C2_flags_0.all = in_ptr[C2_flags_in_idx++]; // Read C2 Flag 291 290 289 288
 C2_flags_1.all = in_ptr[C2_flags_in_idx++]; // Read C2 Flag #   #   293 292


 C2FlagsVect[0] = C2_flags_0.field.flags_4n;    // C2 Flag 0
 C2FlagsVect[1] = C2_flags_0.field.flags_4np1;  // C2 Flag 1
 C2FlagsVect[2] = C2_flags_0.field.flags_4np2;  // C2 Flag 2
 C2FlagsVect[3] = C2_flags_0.field.flags_4np3;  // C2 Flag 3

 C2FlagsVect[4] = C2_flags_1.field.flags_4n;    // C2 Flag 4
 C2FlagsVect[5] = C2_flags_1.field.flags_4np1;  // C2 Flag 5

 data = C2FlagsVect[0] + (C2FlagsVect[1] << 8) + (C2FlagsVect[2] << 16);// # 2 1 0
 data <<= 8; // 3 2 1 #

 data |= ((data_3>>16)&0xFF);

 out_ptr[C2_flags_out_idx] = data;

 C2_flags_out_idx += 7;

 data = C2FlagsVect[3] + (C2FlagsVect[4] << 8) + (C2FlagsVect[5] << 16); // # 5 4 3
 data <<= 8; // 5 4 3 #

 data |= ((data_3>>24)&0xFF);

 out_ptr[C2_flags_out_idx] = data;


  //C2_flags_in_idx : 714
  //C2_flags_out_idx: 687 4*687=2748

#endif

#if (1 == HAVE_SHOCK_MEMORY)
  if (ADPCM_ON == cap_config.adpcm)
  {
    // CD Data Formatting:
    in_idx = 0;
    out_idx = 1;

    for (efm_idx = 0; efm_idx < 49; efm_idx++)
    {
      data = (in_ptr[in_idx] & 0x0000FFFF) << 16;       // #0
      out_ptr[out_idx++] = data;
      data = (in_ptr[in_idx++] & 0xFFFF0000) >> 16;     // #1
      data += ((in_ptr[in_idx] & 0x0000FFFF) << 16);    // #2
      out_ptr[out_idx++] = data;

      data = (in_ptr[in_idx++] & 0xFFFF0000);           // #3
      out_ptr[out_idx++] = data;
      data = in_ptr[in_idx++];                          // #4,#5
      out_ptr[out_idx++] = data;
    }

    /* Copy only mark byte for adpcm enc/dec reset */
    in_idx = 150; //177;
    out_idx = 1;

    data = out_ptr[out_idx];
    data |= ((in_ptr[in_idx] >> 16) & 0xFF);
    out_ptr[out_idx] = data;
  }
  else
#endif
  {
    // CD Data Formatting:
    in_idx = 0;
    out_idx = 2;

    for (efm_idx = 0; efm_idx < 98; efm_idx++) //588
    {
      for (i = 0; i < 6; i++)
      {
        data = in_ptr[in_idx++];
        out_ptr[out_idx++] = data;
      }
      out_idx++; // Skip C2 Flag & Subcode Raw;
    }
  }
}




void AudioInit(void)
{
  //create input bitstream
  AudioBitstream_p = &AudioDecoderBitstreamStructure;

  //AudioBuffer_p_AudioDec = AudioBuffer[0].data;
  /*
  MP3Output_p->channels[0] = (void *) AudioBuffer[0].data;
  MP3Output_p->channels[1] = (void *)(AudioBuffer[0].data + 1); // 4 bytes per sample
  */

  // Cannot assume data is already present in FrameBuffer
  // so leave the decoder in not initialized state
  AudioDecoderNextState = notInitializedAudioDec;

  decoderPlayMode = playModePlay;
}

decoderReturnType AudioDecode(int flag)
{
  t_position position;

  static ElementFlagType nextElementFlag;

  uint8 FB_clearFrom;
  uint8 FB_clearTill;

  while (1)
  {
    switch (AudioDecoderNextState)
    {
    case notInitializedAudioDec:
      {
        // set pointer according to g_FB_readFrom
        AudioBitstream_p->data = (unsigned char *)
                                 FrameBuffer[(g_FB_readFrom % FrameBufferElements) + 1].data;

        AudioBitstream_p->dataLength = 0;

        AudioBitstream_p->dataOffset = 0;

        nextElementFlag = FT_FIRST;

        // Don't leave the loop, there may be more data already available
        AudioDecoderNextState = decodingBlocksAudioDec;

        pBufferElementAudioDec = FrameBuffer[0]; // reset last pBufferElementAudioDec, not to copy the last

        break;
      }


    case decodingBlocksAudioDec:
      {
        // Decoding of uncompressed data is ongoing. Continue until
        // - no more uncompressed data is available
        // - not enough space in output buffer available

        if ((AudioBuffer_p_AudioDec = AudioBufferHaveSpace(kDecoderSampleRate_44100Hz)) == NULL)
        { //output buffer is full
          AudioDecoderNextState = waitingAudioBufferAudioDec;
          return decoderWaitingABempty;
        }

        switch (AudioUpdateBitstream(AudioBitstream_p, flag))
        {
        case waitingForDataAudioDec:
          //not enough data
          return decoderWaitingFBdata;
        case dataEOFAudioDec:
          //EOF
          ClearFBElement(pBufferElementAudioDec.en);
          return decoderEOF;  //if not enough input data, don't decode them, could cause bad output
          //break;
        case dataReadyAudioDec:
          //data ready
          break;
        case immediateEOFAudioDec:
          // request from Controller
          return decoderEOF_immediate;
        }

        AudioBitstream_p->dataOffset = 2352; //2856;

        // Update bitstream data pointers
        AudioDecodeBlock((uint32 *)(AudioBitstream_p->data), (uint32 *) AudioBuffer_p_AudioDec);

        // set number of DECODED bytes
        SetDecodedBytes(AudioBitstream_p->dataLength - AudioBitstream_p->dataOffset);
        //decoderDecodedBytes = decoderReadBytes - (AudioBitstream_p->dataLength - AudioBitstream_p->dataOffset);

        GetCurrentPosition(&position); // xid,playlist
        position.offset = ASUBCODE_2_BYTES(pBufferElementAudioDec.subcode);
		
		pBufferElementAudioDec.subcode.q_subcode.xid = pBufferElementAudioDec.subcode.q_subcode.q_tno;
        
        //clear used FB elements
        FB_clearFrom = GetElementNumber((unsigned char*)(AudioBitstream_p->data));
        FB_clearTill = GetElementNumber((unsigned char*)(AudioBitstream_p->data+AudioBitstream_p->dataOffset));
        SetEmptyFBE(FB_clearFrom,FB_clearTill);

        pBufferElementAudioDec.subcode.event_subcode = 1; // CDDA - info for AB to enable/disable de-emphasis

        //some output samples have been generated
#if (1 == HAVE_SHOCK_MEMORY)
        if (ADPCM_ON == cap_config.adpcm)
        {
          AudioBufferSetFull(197, nextElementFlag, (tDecoderTime_event *)(&(pBufferElementAudioDec.subcode)), &position);   //MP3Output_p->numberOfSamples = 788/4 = 197 mono word
        }
        else
#endif
        {
          AudioBufferSetFull(687, nextElementFlag, (tDecoderTime_event *)(&(pBufferElementAudioDec.subcode)), &position);   //MP3Output_p->numberOfSamples = 2748/4=687 mono word
        }

        nextElementFlag = FT_MIDDLE;

        AudioDecoderNextState = decodingBlocksAudioDec;

        break;
      } //case decodingBlocks



    case waitingAudioBufferAudioDec:
      {
        // Decoding of uncompressed data is going on, but the decoder
        // ran out of space in the AudioBuffer. This means we
        // decode data faster than it is being consumed by
        // the audio hardware. Return to caller to be put to sleep.

        if ((AudioBuffer_p_AudioDec = AudioBufferHaveSpace(kDecoderSampleRate_44100Hz)) == NULL)
        { //output buffer is full
          return decoderWaitingABempty;
        }

        AudioDecoderNextState = decodingBlocksAudioDec;
        break;
      } //case waitingAudioBuffer
    } //switch MP3DecoderNextState
  } //while
}


void AudioKill(DecoderKillType killType)
{
  if (killType == closeOnly)
  {
    AudioDecoderNextState = notInitializedAudioDec;
  }
  else if (killType == destroy)
  {
    //AudioDecoderNextState = notInitializedAudioDec;
    //FREE(MP3Requirements_p->instanceStateSize);
    //FREE(MP3Requirements_p->scratchSize);
  }
}