embdrv/sbc/decoder/srce/bitalloc-sbc.c

/******************************************************************************
 *
 *  Copyright (C) 2014 The Android Open Source Project
 *  Copyright 2003 - 2004 Open Interface North America, Inc. All rights
 *                        reserved.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/*******************************************************************************
  $Revision: #1 $
 ******************************************************************************/

/** @file
@ingroup codec_internal
*/

/**@addgroup codec_internal*/
/**@{*/

#include <oi_codec_sbc_private.h>

static void dualBitAllocation(OI_CODEC_SBC_COMMON_CONTEXT* common) {
  OI_UINT bitcountL;
  OI_UINT bitcountR;
  OI_UINT bitpoolPreferenceL = 0;
  OI_UINT bitpoolPreferenceR = 0;
  BITNEED_UNION1 bitneedsL;
  BITNEED_UNION1 bitneedsR;

  bitcountL = computeBitneed(common, bitneedsL.uint8, 0, &bitpoolPreferenceL);
  bitcountR = computeBitneed(common, bitneedsR.uint8, 1, &bitpoolPreferenceR);

  oneChannelBitAllocation(common, &bitneedsL, 0, bitcountL);
  oneChannelBitAllocation(common, &bitneedsR, 1, bitcountR);
}

static void stereoBitAllocation(OI_CODEC_SBC_COMMON_CONTEXT* common) {
  const OI_UINT nrof_subbands = common->frameInfo.nrof_subbands;
  BITNEED_UNION2 bitneeds;
  OI_UINT excess;
  OI_INT bitadjust;
  OI_UINT bitcount;
  OI_UINT sbL;
  OI_UINT sbR;
  OI_UINT bitpoolPreference = 0;

  bitcount = computeBitneed(common, &bitneeds.uint8[0], 0, &bitpoolPreference);
  bitcount += computeBitneed(common, &bitneeds.uint8[nrof_subbands], 1,
                             &bitpoolPreference);

  {
    OI_UINT ex;
    bitadjust = adjustToFitBitpool(common->frameInfo.bitpool, bitneeds.uint32,
                                   2 * nrof_subbands, bitcount, &ex);
    /* We want the compiler to put excess into a register */
    excess = ex;
  }
  sbL = 0;
  sbR = nrof_subbands;
  while (sbL < nrof_subbands) {
    excess = allocAdjustedBits(&common->bits.uint8[sbL],
                               bitneeds.uint8[sbL] + bitadjust, excess);
    ++sbL;
    excess = allocAdjustedBits(&common->bits.uint8[sbR],
                               bitneeds.uint8[sbR] + bitadjust, excess);
    ++sbR;
  }
  sbL = 0;
  sbR = nrof_subbands;
  while (excess) {
    excess = allocExcessBits(&common->bits.uint8[sbL], excess);
    ++sbL;
    if (!excess) {
      break;
    }
    excess = allocExcessBits(&common->bits.uint8[sbR], excess);
    ++sbR;
  }
}

static const BIT_ALLOC balloc[] = {
    monoBitAllocation,   /* SBC_MONO */
    dualBitAllocation,   /* SBC_DUAL_CHANNEL */
    stereoBitAllocation, /* SBC_STEREO */
    stereoBitAllocation  /* SBC_JOINT_STEREO */
};

PRIVATE void OI_SBC_ComputeBitAllocation(OI_CODEC_SBC_COMMON_CONTEXT* common) {
  OI_ASSERT(common->frameInfo.bitpool <= OI_SBC_MaxBitpool(&common->frameInfo));
  OI_ASSERT(common->frameInfo.mode < OI_ARRAYSIZE(balloc));

  /*
   * Using an array of function pointers prevents the compiler from creating a
   * suboptimal
   * monolithic inlined bit allocation function.
   */
  balloc[common->frameInfo.mode](common);
}

uint32_t OI_CODEC_SBC_CalculateBitrate(OI_CODEC_SBC_FRAME_INFO* frame) {
  return internal_CalculateBitrate(frame);
}

/*
 * Return the current maximum bitneed and clear it.
 */
uint8_t OI_CODEC_SBC_GetMaxBitneed(OI_CODEC_SBC_COMMON_CONTEXT* common) {
  uint8_t max = common->maxBitneed;

  common->maxBitneed = 0;
  return max;
}

/*
 * Calculates the bitpool size for a given frame length
 */
uint16_t OI_CODEC_SBC_CalculateBitpool(OI_CODEC_SBC_FRAME_INFO* frame,
                                       uint16_t frameLen) {
  uint16_t nrof_subbands = frame->nrof_subbands;
  uint16_t nrof_blocks = frame->nrof_blocks;
  uint16_t hdr;
  uint16_t bits;

  if (frame->mode == SBC_JOINT_STEREO) {
    hdr = 9 * nrof_subbands;
  } else {
    if (frame->mode == SBC_MONO) {
      hdr = 4 * nrof_subbands;
    } else {
      hdr = 8 * nrof_subbands;
    }
    if (frame->mode == SBC_DUAL_CHANNEL) {
      nrof_blocks *= 2;
    }
  }
  bits = 8 * (frameLen - SBC_HEADER_LEN) - hdr;
  return DIVIDE(bits, nrof_blocks);
}

uint16_t OI_CODEC_SBC_CalculatePcmBytes(OI_CODEC_SBC_COMMON_CONTEXT* common) {
  return sizeof(int16_t) * common->pcmStride * common->frameInfo.nrof_subbands *
         common->frameInfo.nrof_blocks;
}

uint16_t OI_CODEC_SBC_CalculateFramelen(OI_CODEC_SBC_FRAME_INFO* frame) {
  return internal_CalculateFramelen(frame);
}

/**@}*/