modules/audio_coding/codecs/isac/fix/source/decode.c

/*
 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

/*
 * decode.c
 *
 * This C file contains the internal decoding function.
 *
 */

#include <string.h>

#include "modules/audio_coding/codecs/isac/fix/source/bandwidth_estimator.h"
#include "modules/audio_coding/codecs/isac/fix/source/codec.h"
#include "modules/audio_coding/codecs/isac/fix/source/entropy_coding.h"
#include "modules/audio_coding/codecs/isac/fix/source/pitch_estimator.h"
#include "modules/audio_coding/codecs/isac/fix/source/settings.h"
#include "modules/audio_coding/codecs/isac/fix/source/structs.h"




int WebRtcIsacfix_DecodeImpl(int16_t* signal_out16,
                             IsacFixDecoderInstance* ISACdec_obj,
                             size_t* current_framesamples)
{
  int k;
  int err;
  int16_t BWno;
  int len = 0;

  int16_t model;


  int16_t Vector_Word16_1[FRAMESAMPLES/2];
  int16_t Vector_Word16_2[FRAMESAMPLES/2];

  int32_t Vector_Word32_1[FRAMESAMPLES/2];
  int32_t Vector_Word32_2[FRAMESAMPLES/2];

  int16_t lofilt_coefQ15[ORDERLO*SUBFRAMES]; //refl. coeffs
  int16_t hifilt_coefQ15[ORDERHI*SUBFRAMES]; //refl. coeffs
  int32_t gain_lo_hiQ17[2*SUBFRAMES];

  int16_t PitchLags_Q7[PITCH_SUBFRAMES];
  int16_t PitchGains_Q12[PITCH_SUBFRAMES];
  int16_t AvgPitchGain_Q12;

  int16_t tmp_1, tmp_2;
  int32_t tmp32a;
  int16_t gainQ13;


  size_t frame_nb; /* counter */
  size_t frame_mode; /* 0 for 30ms, 1 for 60ms */
  static const size_t kProcessedSamples = 480; /* 480 (for both 30, 60 ms) */

  /* PLC */
  int16_t overlapWin[ 240 ];

  (ISACdec_obj->bitstr_obj).W_upper = 0xFFFFFFFF;
  (ISACdec_obj->bitstr_obj).streamval = 0;
  (ISACdec_obj->bitstr_obj).stream_index = 0;
  (ISACdec_obj->bitstr_obj).full = 1;


  /* decode framelength and BW estimation - not used, only for stream pointer*/
  err = WebRtcIsacfix_DecodeFrameLen(&ISACdec_obj->bitstr_obj, current_framesamples);
  if (err<0)  // error check
    return err;

  frame_mode = *current_framesamples / MAX_FRAMESAMPLES;  /* 0, or 1 */

  err = WebRtcIsacfix_DecodeSendBandwidth(&ISACdec_obj->bitstr_obj, &BWno);
  if (err<0)  // error check
    return err;

  /* one loop if it's one frame (30ms), two loops if two frames bundled together
   * (60ms) */
  for (frame_nb = 0; frame_nb <= frame_mode; frame_nb++) {

    /* decode & dequantize pitch parameters */
    err = WebRtcIsacfix_DecodePitchGain(&(ISACdec_obj->bitstr_obj), PitchGains_Q12);
    if (err<0)  // error check
      return err;

    err = WebRtcIsacfix_DecodePitchLag(&ISACdec_obj->bitstr_obj, PitchGains_Q12, PitchLags_Q7);
    if (err<0)  // error check
      return err;

    AvgPitchGain_Q12 = (int16_t)(((int32_t)PitchGains_Q12[0] + PitchGains_Q12[1] + PitchGains_Q12[2] + PitchGains_Q12[3])>>2);

    /* decode & dequantize FiltCoef */
    err = WebRtcIsacfix_DecodeLpc(gain_lo_hiQ17, lofilt_coefQ15, hifilt_coefQ15,
                                  &ISACdec_obj->bitstr_obj, &model);

    if (err<0)  // error check
      return err;

    /* decode & dequantize spectrum */
    len = WebRtcIsacfix_DecodeSpec(&ISACdec_obj->bitstr_obj, Vector_Word16_1, Vector_Word16_2, AvgPitchGain_Q12);
    if (len < 0)  // error check
      return len;

    // Why does this need Q16 in and out? /JS
    WebRtcIsacfix_Spec2Time(Vector_Word16_1, Vector_Word16_2, Vector_Word32_1, Vector_Word32_2);

    for (k=0; k<FRAMESAMPLES/2; k++) {
      // Q16 -> Q9.
      Vector_Word16_1[k] = (int16_t)((Vector_Word32_1[k] + 64) >> 7);
    }

    /* ----  If this is recovery frame ---- */
    if( (ISACdec_obj->plcstr_obj).used == PLC_WAS_USED )
    {
      (ISACdec_obj->plcstr_obj).used = PLC_NOT_USED;
      if( (ISACdec_obj->plcstr_obj).B < 1000 )
      {
        (ISACdec_obj->plcstr_obj).decayCoeffPriodic = 4000;
      }

      ISACdec_obj->plcstr_obj.decayCoeffPriodic = WEBRTC_SPL_WORD16_MAX;    /* DECAY_RATE is in Q15 */
      ISACdec_obj->plcstr_obj.decayCoeffNoise = WEBRTC_SPL_WORD16_MAX;    /* DECAY_RATE is in Q15 */
      ISACdec_obj->plcstr_obj.pitchCycles = 0;

      PitchGains_Q12[0] = (int16_t)(PitchGains_Q12[0] * 700 >> 10);

      /* ---- Add-overlap ---- */
      WebRtcSpl_GetHanningWindow( overlapWin, RECOVERY_OVERLAP );
      for( k = 0; k < RECOVERY_OVERLAP; k++ )
        Vector_Word16_1[k] = WebRtcSpl_AddSatW16(
            (int16_t)(ISACdec_obj->plcstr_obj.overlapLP[k] *
                overlapWin[RECOVERY_OVERLAP - k - 1] >> 14),
            (int16_t)(Vector_Word16_1[k] * overlapWin[k] >> 14));



    }

    /* --- Store side info --- */
    if( frame_nb == frame_mode )
    {
      /* --- LPC info */
      WEBRTC_SPL_MEMCPY_W16( (ISACdec_obj->plcstr_obj).lofilt_coefQ15, &lofilt_coefQ15[(SUBFRAMES-1)*ORDERLO], ORDERLO );
      WEBRTC_SPL_MEMCPY_W16( (ISACdec_obj->plcstr_obj).hifilt_coefQ15, &hifilt_coefQ15[(SUBFRAMES-1)*ORDERHI], ORDERHI );
      (ISACdec_obj->plcstr_obj).gain_lo_hiQ17[0] = gain_lo_hiQ17[(SUBFRAMES-1) * 2];
      (ISACdec_obj->plcstr_obj).gain_lo_hiQ17[1] = gain_lo_hiQ17[(SUBFRAMES-1) * 2 + 1];

      /* --- LTP info */
      (ISACdec_obj->plcstr_obj).AvgPitchGain_Q12 = PitchGains_Q12[3];
      (ISACdec_obj->plcstr_obj).lastPitchGain_Q12 = PitchGains_Q12[3];
      (ISACdec_obj->plcstr_obj).lastPitchLag_Q7 = PitchLags_Q7[3];

      if( PitchLags_Q7[3] < 3000 )
        (ISACdec_obj->plcstr_obj).lastPitchLag_Q7 += PitchLags_Q7[3];

      WEBRTC_SPL_MEMCPY_W16( (ISACdec_obj->plcstr_obj).prevPitchInvIn, Vector_Word16_1, FRAMESAMPLES/2 );

    }
    /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */

    /* inverse pitch filter */
    WebRtcIsacfix_PitchFilter(Vector_Word16_1, Vector_Word16_2, &ISACdec_obj->pitchfiltstr_obj, PitchLags_Q7, PitchGains_Q12, 4);

    if( frame_nb == frame_mode )
    {
      WEBRTC_SPL_MEMCPY_W16( (ISACdec_obj->plcstr_obj).prevPitchInvOut, &(Vector_Word16_2[FRAMESAMPLES/2 - (PITCH_MAX_LAG + 10)]), PITCH_MAX_LAG );
    }


    /* reduce gain to compensate for pitch enhancer */
    /* gain = 1.0f - 0.45f * AvgPitchGain; */
    tmp32a = AvgPitchGain_Q12 * 29;  // Q18
    gainQ13 = (int16_t)((262144 - tmp32a) >> 5);  // Q18 -> Q13.

    for (k = 0; k < FRAMESAMPLES/2; k++)
    {
      Vector_Word32_1[k] = (Vector_Word16_2[k] * gainQ13) * (1 << 3);  // Q25
    }


    /* perceptual post-filtering (using normalized lattice filter) */
    WebRtcIsacfix_NormLatticeFilterAr(ORDERLO, (ISACdec_obj->maskfiltstr_obj).PostStateLoGQ0,
                                      Vector_Word32_1, lofilt_coefQ15, gain_lo_hiQ17, 0, Vector_Word16_1);

    /* --- Store Highpass Residual --- */
    for (k = 0; k < FRAMESAMPLES/2; k++)
      Vector_Word32_1[k] = Vector_Word32_2[k] * (1 << 9);  // Q16 -> Q25

    for( k = 0; k < PITCH_MAX_LAG + 10; k++ )
      (ISACdec_obj->plcstr_obj).prevHP[k] = Vector_Word32_1[FRAMESAMPLES/2 - (PITCH_MAX_LAG + 10) + k];


    WebRtcIsacfix_NormLatticeFilterAr(ORDERHI, (ISACdec_obj->maskfiltstr_obj).PostStateHiGQ0,
                                      Vector_Word32_1, hifilt_coefQ15, gain_lo_hiQ17, 1, Vector_Word16_2);

    /* recombine the 2 bands */

    /* Form the polyphase signals, and compensate for DC offset */
    for (k=0;k<FRAMESAMPLES/2;k++) {
      tmp_1 = (int16_t)WebRtcSpl_SatW32ToW16(((int32_t)Vector_Word16_1[k]+Vector_Word16_2[k] + 1)); /* Construct a new upper channel signal*/
      tmp_2 = (int16_t)WebRtcSpl_SatW32ToW16(((int32_t)Vector_Word16_1[k]-Vector_Word16_2[k])); /* Construct a new lower channel signal*/
      Vector_Word16_1[k] = tmp_1;
      Vector_Word16_2[k] = tmp_2;
    }

    WebRtcIsacfix_FilterAndCombine1(Vector_Word16_1,
                                    Vector_Word16_2,
                                    signal_out16 + frame_nb * kProcessedSamples,
                                    &ISACdec_obj->postfiltbankstr_obj);

  }
  return len;
}