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sbc.c

/*
 *
 *  Bluetooth low-complexity, subband codec (SBC) library
 *
 *  Copyright (C) 2004-2008  Marcel Holtmann <marcel@holtmann.org>
 *  Copyright (C) 2004-2005  Henryk Ploetz <henryk@ploetzli.ch>
 *  Copyright (C) 2005-2008  Brad Midgley <bmidgley@xmission.com>
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/* todo items:

  use a log2 table for byte integer scale factors calculation (sum log2 results
  for high and low bytes) fill bitpool by 16 bits instead of one at a time in
  bits allocation/bitpool generation port to the dsp

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>

#include "sbc_math.h"
#include "sbc_tables.h"

#include "sbc.h"

#define SBC_SYNCWORD    0x9C

/* This structure contains an unpacked SBC frame.
   Yes, there is probably quite some unused space herein */
struct sbc_frame {
      uint8_t frequency;
      uint8_t block_mode;
      uint8_t blocks;
      enum {
            MONO        = SBC_MODE_MONO,
            DUAL_CHANNEL      = SBC_MODE_DUAL_CHANNEL,
            STEREO            = SBC_MODE_STEREO,
            JOINT_STEREO      = SBC_MODE_JOINT_STEREO
      } mode;
      uint8_t channels;
      enum {
            LOUDNESS    = SBC_AM_LOUDNESS,
            SNR         = SBC_AM_SNR
      } allocation;
      uint8_t subband_mode;
      uint8_t subbands;
      uint8_t bitpool;
      uint8_t codesize;
      uint8_t length;

      /* bit number x set means joint stereo has been used in subband x */
      uint8_t joint;

      /* only the lower 4 bits of every element are to be used */
      uint8_t scale_factor[2][8];

      /* raw integer subband samples in the frame */

      int32_t sb_sample_f[16][2][8];
      int32_t sb_sample[16][2][8];  /* modified subband samples */
      int16_t pcm_sample[2][16*8];  /* original pcm audio samples */
};

struct sbc_decoder_state {
      int subbands;
      int32_t V[2][170];
      int offset[2][16];
};

struct sbc_encoder_state {
      int subbands;
      int position[2];
      int32_t X[2][160];
};

/*
 * Calculates the CRC-8 of the first len bits in data
 */
static const uint8_t crc_table[256] = {
      0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53,
      0xE8, 0xF5, 0xD2, 0xCF, 0x9C, 0x81, 0xA6, 0xBB,
      0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4, 0x83, 0x9E,
      0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76,
      0x87, 0x9A, 0xBD, 0xA0, 0xF3, 0xEE, 0xC9, 0xD4,
      0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06, 0x21, 0x3C,
      0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19,
      0xA2, 0xBF, 0x98, 0x85, 0xD6, 0xCB, 0xEC, 0xF1,
      0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A, 0x5D, 0x40,
      0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8,
      0xDE, 0xC3, 0xE4, 0xF9, 0xAA, 0xB7, 0x90, 0x8D,
      0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F, 0x78, 0x65,
      0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7,
      0x7C, 0x61, 0x46, 0x5B, 0x08, 0x15, 0x32, 0x2F,
      0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30, 0x17, 0x0A,
      0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2,
      0x26, 0x3B, 0x1C, 0x01, 0x52, 0x4F, 0x68, 0x75,
      0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7, 0x80, 0x9D,
      0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8,
      0x03, 0x1E, 0x39, 0x24, 0x77, 0x6A, 0x4D, 0x50,
      0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8, 0xEF, 0xF2,
      0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A,
      0x6C, 0x71, 0x56, 0x4B, 0x18, 0x05, 0x22, 0x3F,
      0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED, 0xCA, 0xD7,
      0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66,
      0xDD, 0xC0, 0xE7, 0xFA, 0xA9, 0xB4, 0x93, 0x8E,
      0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91, 0xB6, 0xAB,
      0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43,
      0xB2, 0xAF, 0x88, 0x95, 0xC6, 0xDB, 0xFC, 0xE1,
      0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33, 0x14, 0x09,
      0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C,
      0x97, 0x8A, 0xAD, 0xB0, 0xE3, 0xFE, 0xD9, 0xC4
};

static uint8_t sbc_crc8(const uint8_t *data, size_t len)
{
      uint8_t crc = 0x0f;
      size_t i;
      uint8_t octet;

      for (i = 0; i < len / 8; i++)
            crc = crc_table[crc ^ data[i]];

      octet = data[i];
      for (i = 0; i < len % 8; i++) {
            unsigned char bit = ((octet ^ crc) & 0x80) >> 7;

            crc = ((crc & 0x7f) << 1) ^ (bit ? 0x1d : 0);

            octet = octet << 1;
      }

      return crc;
}

/*
 * Code straight from the spec to calculate the bits array
 * Takes a pointer to the frame in question, a pointer to the bits array and
 * the sampling frequency (as 2 bit integer)
 */
static void sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8])
{
      uint8_t sf = frame->frequency;

      if (frame->mode == MONO || frame->mode == DUAL_CHANNEL) {
            int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
            int ch, sb;

            for (ch = 0; ch < frame->channels; ch++) {
                  max_bitneed = 0;
                  if (frame->allocation == SNR) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              bitneed[ch][sb] = frame->scale_factor[ch][sb];
                              if (bitneed[ch][sb] > max_bitneed)
                                    max_bitneed = bitneed[ch][sb];
                        }
                  } else {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if (frame->scale_factor[ch][sb] == 0)
                                    bitneed[ch][sb] = -5;
                              else {
                                    if (frame->subbands == 4)
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
                                    else
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
                                    if (loudness > 0)
                                          bitneed[ch][sb] = loudness / 2;
                                    else
                                          bitneed[ch][sb] = loudness;
                              }
                              if (bitneed[ch][sb] > max_bitneed)
                                    max_bitneed = bitneed[ch][sb];
                        }
                  }

                  bitcount = 0;
                  slicecount = 0;
                  bitslice = max_bitneed + 1;
                  do {
                        bitslice--;
                        bitcount += slicecount;
                        slicecount = 0;
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16))
                                    slicecount++;
                              else if (bitneed[ch][sb] == bitslice + 1)
                                    slicecount += 2;
                        }
                  } while (bitcount + slicecount < frame->bitpool);

                  if (bitcount + slicecount == frame->bitpool) {
                        bitcount += slicecount;
                        bitslice--;
                  }

                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] < bitslice + 2)
                              bits[ch][sb] = 0;
                        else {
                              bits[ch][sb] = bitneed[ch][sb] - bitslice;
                              if (bits[ch][sb] > 16)
                                    bits[ch][sb] = 16;
                        }
                  }

                  for (sb = 0; bitcount < frame->bitpool && sb < frame->subbands; sb++) {
                        if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
                              bits[ch][sb]++;
                              bitcount++;
                        } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
                              bits[ch][sb] = 2;
                              bitcount += 2;
                        }
                  }

                  for (sb = 0; bitcount < frame->bitpool && sb < frame->subbands; sb++) {
                        if (bits[ch][sb] < 16) {
                              bits[ch][sb]++;
                              bitcount++;
                        }
                  }

            }

      } else if (frame->mode == STEREO || frame->mode == JOINT_STEREO) {
            int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
            int ch, sb;

            max_bitneed = 0;
            if (frame->allocation == SNR) {
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              bitneed[ch][sb] = frame->scale_factor[ch][sb];
                              if (bitneed[ch][sb] > max_bitneed)
                                    max_bitneed = bitneed[ch][sb];
                        }
                  }
            } else {
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if (frame->scale_factor[ch][sb] == 0)
                                    bitneed[ch][sb] = -5;
                              else {
                                    if (frame->subbands == 4)
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
                                    else
                                          loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
                                    if (loudness > 0)
                                          bitneed[ch][sb] = loudness / 2;
                                    else
                                          bitneed[ch][sb] = loudness;
                              }
                              if (bitneed[ch][sb] > max_bitneed)
                                    max_bitneed = bitneed[ch][sb];
                        }
                  }
            }

            bitcount = 0;
            slicecount = 0;
            bitslice = max_bitneed + 1;
            do {
                  bitslice--;
                  bitcount += slicecount;
                  slicecount = 0;
                  for (ch = 0; ch < 2; ch++) {
                        for (sb = 0; sb < frame->subbands; sb++) {
                              if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16))
                                    slicecount++;
                              else if (bitneed[ch][sb] == bitslice + 1)
                                    slicecount += 2;
                        }
                  }
            } while (bitcount + slicecount < frame->bitpool);

            if (bitcount + slicecount == frame->bitpool) {
                  bitcount += slicecount;
                  bitslice--;
            }

            for (ch = 0; ch < 2; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (bitneed[ch][sb] < bitslice + 2) {
                              bits[ch][sb] = 0;
                        } else {
                              bits[ch][sb] = bitneed[ch][sb] - bitslice;
                              if (bits[ch][sb] > 16)
                                    bits[ch][sb] = 16;
                        }
                  }
            }

            ch = 0;
            sb = 0;
            while (bitcount < frame->bitpool) {
                  if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
                        bits[ch][sb]++;
                        bitcount++;
                  } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
                        bits[ch][sb] = 2;
                        bitcount += 2;
                  }
                  if (ch == 1) {
                        ch = 0;
                        sb++;
                        if (sb >= frame->subbands) break;
                  } else
                        ch = 1;
            }

            ch = 0;
            sb = 0;
            while (bitcount < frame->bitpool) {
                  if (bits[ch][sb] < 16) {
                        bits[ch][sb]++;
                        bitcount++;
                  }
                  if (ch == 1) {
                        ch = 0;
                        sb++;
                        if (sb >= frame->subbands) break;
                  } else
                        ch = 1;
            }

      }

}

/*
 * Unpacks a SBC frame at the beginning of the stream in data,
 * which has at most len bytes into frame.
 * Returns the length in bytes of the packed frame, or a negative
 * value on error. The error codes are:
 *
 *  -1   Data stream too short
 *  -2   Sync byte incorrect
 *  -3   CRC8 incorrect
 *  -4   Bitpool value out of bounds
 */
static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame,
                        size_t len)
{
      int consumed;
      /* Will copy the parts of the header that are relevant to crc
       * calculation here */
      uint8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
      int crc_pos = 0;
      int32_t temp;

      int audio_sample;
      int ch, sb, blk, bit;   /* channel, subband, block and bit standard
                           counters */
      int bits[2][8];         /* bits distribution */
      uint32_t levels[2][8];  /* levels derived from that */

      if (len < 4)
            return -1;

      if (data[0] != SBC_SYNCWORD)
            return -2;

      frame->frequency = (data[1] >> 6) & 0x03;

      frame->block_mode = (data[1] >> 4) & 0x03;
      switch (frame->block_mode) {
      case SBC_BLK_4:
            frame->blocks = 4;
            break;
      case SBC_BLK_8:
            frame->blocks = 8;
            break;
      case SBC_BLK_12:
            frame->blocks = 12;
            break;
      case SBC_BLK_16:
            frame->blocks = 16;
            break;
      }

      frame->mode = (data[1] >> 2) & 0x03;
      switch (frame->mode) {
      case MONO:
            frame->channels = 1;
            break;
      case DUAL_CHANNEL:      /* fall-through */
      case STEREO:
      case JOINT_STEREO:
            frame->channels = 2;
            break;
      }

      frame->allocation = (data[1] >> 1) & 0x01;

      frame->subband_mode = (data[1] & 0x01);
      frame->subbands = frame->subband_mode ? 8 : 4;

      frame->bitpool = data[2];

      if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) &&
                  frame->bitpool > 16 * frame->subbands)
            return -4;

      if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) &&
                  frame->bitpool > 32 * frame->subbands)
            return -4;

      /* data[3] is crc, we're checking it later */

      consumed = 32;

      crc_header[0] = data[1];
      crc_header[1] = data[2];
      crc_pos = 16;

      if (frame->mode == JOINT_STEREO) {
            if (len * 8 < consumed + frame->subbands)
                  return -1;

            frame->joint = 0x00;
            for (sb = 0; sb < frame->subbands - 1; sb++)
                  frame->joint |= ((data[4] >> (7 - sb)) & 0x01) << sb;
            if (frame->subbands == 4)
                  crc_header[crc_pos / 8] = data[4] & 0xf0;
            else
                  crc_header[crc_pos / 8] = data[4];

            consumed += frame->subbands;
            crc_pos += frame->subbands;
      }

      if (len * 8 < consumed + (4 * frame->subbands * frame->channels))
            return -1;

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  /* FIXME assert(consumed % 4 == 0); */
                  frame->scale_factor[ch][sb] =
                        (data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F;
                  crc_header[crc_pos >> 3] |=
                        frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7));

                  consumed += 4;
                  crc_pos += 4;
            }
      }

      if (data[3] != sbc_crc8(crc_header, crc_pos))
            return -3;

      sbc_calculate_bits(frame, bits);

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++)
                  levels[ch][sb] = (1 << bits[ch][sb]) - 1;
      }

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (levels[ch][sb] > 0) {
                              audio_sample = 0;
                              for (bit = 0; bit < bits[ch][sb]; bit++) {
                                    if (consumed > len * 8)
                                          return -1;

                                    if ((data[consumed >> 3] >> (7 - (consumed & 0x7))) & 0x01)
                                          audio_sample |= 1 << (bits[ch][sb] - bit - 1);

                                    consumed++;
                              }

                              frame->sb_sample[blk][ch][sb] =
                                    (((audio_sample << 1) | 1) << frame->scale_factor[ch][sb]) /
                                    levels[ch][sb] - (1 << frame->scale_factor[ch][sb]);
                        } else
                              frame->sb_sample[blk][ch][sb] = 0;
                  }
            }
      }

      if (frame->mode == JOINT_STEREO) {
            for (blk = 0; blk < frame->blocks; blk++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (frame->joint & (0x01 << sb)) {
                              temp = frame->sb_sample[blk][0][sb] +
                                    frame->sb_sample[blk][1][sb];
                              frame->sb_sample[blk][1][sb] =
                                    frame->sb_sample[blk][0][sb] -
                                    frame->sb_sample[blk][1][sb];
                              frame->sb_sample[blk][0][sb] = temp;
                        }
                  }
            }
      }

      if ((consumed & 0x7) != 0)
            consumed += 8 - (consumed & 0x7);

      return consumed >> 3;
}

static void sbc_decoder_init(struct sbc_decoder_state *state,
                        const struct sbc_frame *frame)
{
      int i, ch;

      memset(state->V, 0, sizeof(state->V));
      state->subbands = frame->subbands;

      for (ch = 0; ch < 2; ch++)
            for (i = 0; i < frame->subbands * 2; i++)
                  state->offset[ch][i] = (10 * i + 10);
}

static inline void sbc_synthesize_four(struct sbc_decoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int i, k, idx;
      int32_t *v = state->V[ch];
      int *offset = state->offset[ch];

      for (i = 0; i < 8; i++) {
            /* Shifting */
            offset[i]--;
            if (offset[i] < 0) {
                  offset[i] = 79;
                  memcpy(v + 80, v, 9 * sizeof(*v));
            }

            /* Distribute the new matrix value to the shifted position */
            v[offset[i]] = SCALE4_STAGED1(
                  MULA(synmatrix4[i][0], frame->sb_sample[blk][ch][0],
                  MULA(synmatrix4[i][1], frame->sb_sample[blk][ch][1],
                  MULA(synmatrix4[i][2], frame->sb_sample[blk][ch][2],
                  MUL (synmatrix4[i][3], frame->sb_sample[blk][ch][3])))));
      }

      /* Compute the samples */
      for (idx = 0, i = 0; i < 4; i++, idx += 5) {
            k = (i + 4) & 0xf;

            /* Store in output, Q0 */
            frame->pcm_sample[ch][blk * 4 + i] = SCALE4_STAGED2(
                  MULA(v[offset[i] + 0], sbc_proto_4_40m0[idx + 0],
                  MULA(v[offset[k] + 1], sbc_proto_4_40m1[idx + 0],
                  MULA(v[offset[i] + 2], sbc_proto_4_40m0[idx + 1],
                  MULA(v[offset[k] + 3], sbc_proto_4_40m1[idx + 1],
                  MULA(v[offset[i] + 4], sbc_proto_4_40m0[idx + 2],
                  MULA(v[offset[k] + 5], sbc_proto_4_40m1[idx + 2],
                  MULA(v[offset[i] + 6], sbc_proto_4_40m0[idx + 3],
                  MULA(v[offset[k] + 7], sbc_proto_4_40m1[idx + 3],
                  MULA(v[offset[i] + 8], sbc_proto_4_40m0[idx + 4],
                  MUL( v[offset[k] + 9], sbc_proto_4_40m1[idx + 4])))))))))));
      }
}

static inline void sbc_synthesize_eight(struct sbc_decoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int i, j, k, idx;
      int *offset = state->offset[ch];

      for (i = 0; i < 16; i++) {
            /* Shifting */
            offset[i]--;
            if (offset[i] < 0) {
                  offset[i] = 159;
                  for (j = 0; j < 9; j++)
                        state->V[ch][j + 160] = state->V[ch][j];
            }

            /* Distribute the new matrix value to the shifted position */
            state->V[ch][offset[i]] = SCALE8_STAGED1(
                  MULA(synmatrix8[i][0], frame->sb_sample[blk][ch][0],
                  MULA(synmatrix8[i][1], frame->sb_sample[blk][ch][1],
                  MULA(synmatrix8[i][2], frame->sb_sample[blk][ch][2],
                  MULA(synmatrix8[i][3], frame->sb_sample[blk][ch][3],
                  MULA(synmatrix8[i][4], frame->sb_sample[blk][ch][4],
                  MULA(synmatrix8[i][5], frame->sb_sample[blk][ch][5],
                  MULA(synmatrix8[i][6], frame->sb_sample[blk][ch][6],
                  MUL( synmatrix8[i][7], frame->sb_sample[blk][ch][7])))))))));
      }

      /* Compute the samples */
      for (idx = 0, i = 0; i < 8; i++, idx += 5) {
            k = (i + 8) & 0xf;

            /* Store in output */
            frame->pcm_sample[ch][blk * 8 + i] = SCALE8_STAGED2( // Q0
                  MULA(state->V[ch][offset[i] + 0], sbc_proto_8_80m0[idx + 0],
                  MULA(state->V[ch][offset[k] + 1], sbc_proto_8_80m1[idx + 0],
                  MULA(state->V[ch][offset[i] + 2], sbc_proto_8_80m0[idx + 1],
                  MULA(state->V[ch][offset[k] + 3], sbc_proto_8_80m1[idx + 1],
                  MULA(state->V[ch][offset[i] + 4], sbc_proto_8_80m0[idx + 2],
                  MULA(state->V[ch][offset[k] + 5], sbc_proto_8_80m1[idx + 2],
                  MULA(state->V[ch][offset[i] + 6], sbc_proto_8_80m0[idx + 3],
                  MULA(state->V[ch][offset[k] + 7], sbc_proto_8_80m1[idx + 3],
                  MULA(state->V[ch][offset[i] + 8], sbc_proto_8_80m0[idx + 4],
                  MUL( state->V[ch][offset[k] + 9], sbc_proto_8_80m1[idx + 4])))))))))));
      }
}

static int sbc_synthesize_audio(struct sbc_decoder_state *state,
                        struct sbc_frame *frame)
{
      int ch, blk;

      switch (frame->subbands) {
      case 4:
            for (ch = 0; ch < frame->channels; ch++) {
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_synthesize_four(state, frame, ch, blk);
            }
            return frame->blocks * 4;

      case 8:
            for (ch = 0; ch < frame->channels; ch++) {
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_synthesize_eight(state, frame, ch, blk);
            }
            return frame->blocks * 8;

      default:
            return -EIO;
      }
}

static void sbc_encoder_init(struct sbc_encoder_state *state,
                        const struct sbc_frame *frame)
{
      memset(&state->X, 0, sizeof(state->X));
      state->subbands = frame->subbands;
      state->position[0] = state->position[1] = 9 * frame->subbands;
}

static inline void _sbc_analyze_four(const int32_t *in, int32_t *out)
{
      sbc_fixed_t t[8], s[5];

      t[0] = SCALE4_STAGE1( /* Q8 */
            MULA(_sbc_proto_4[0], in[8] - in[32], /* Q18 */
            MUL( _sbc_proto_4[1], in[16] - in[24])));

      t[1] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[2], in[1],
            MULA(_sbc_proto_4[3], in[9],
            MULA(_sbc_proto_4[4], in[17],
            MULA(_sbc_proto_4[5], in[25],
            MUL( _sbc_proto_4[6], in[33]))))));

      t[2] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[7], in[2],
            MULA(_sbc_proto_4[8], in[10],
            MULA(_sbc_proto_4[9], in[18],
            MULA(_sbc_proto_4[10], in[26],
            MUL( _sbc_proto_4[11], in[34]))))));

      t[3] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[12], in[3],
            MULA(_sbc_proto_4[13], in[11],
            MULA(_sbc_proto_4[14], in[19],
            MULA(_sbc_proto_4[15], in[27],
            MUL( _sbc_proto_4[16], in[35]))))));

      t[4] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[17], in[4] + in[36],
            MULA(_sbc_proto_4[18], in[12] + in[28],
            MUL( _sbc_proto_4[19], in[20]))));

      t[5] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[16], in[5],
            MULA(_sbc_proto_4[15], in[13],
            MULA(_sbc_proto_4[14], in[21],
            MULA(_sbc_proto_4[13], in[29],
            MUL( _sbc_proto_4[12], in[37]))))));

      /* don't compute t[6]... this term always multiplies
       * with cos(pi/2) = 0 */

      t[7] = SCALE4_STAGE1(
            MULA(_sbc_proto_4[6], in[7],
            MULA(_sbc_proto_4[5], in[15],
            MULA(_sbc_proto_4[4], in[23],
            MULA(_sbc_proto_4[3], in[31],
            MUL( _sbc_proto_4[2], in[39]))))));

      s[0] = MUL( _anamatrix4[0], t[0] + t[4]);
      s[1] = MUL( _anamatrix4[2], t[2]);
      s[2] = MULA(_anamatrix4[1], t[1] + t[3],
            MUL(_anamatrix4[3], t[5]));
      s[3] = MULA(_anamatrix4[3], t[1] + t[3],
            MUL(_anamatrix4[1], -t[5] + t[7]));
      s[4] = MUL( _anamatrix4[3], t[7]);

      out[0] = SCALE4_STAGE2( s[0] + s[1] + s[2] + s[4]); /* Q0 */
      out[1] = SCALE4_STAGE2(-s[0] + s[1] + s[3]);
      out[2] = SCALE4_STAGE2(-s[0] + s[1] - s[3]);
      out[3] = SCALE4_STAGE2( s[0] + s[1] - s[2] - s[4]);
}

static inline void sbc_analyze_four(struct sbc_encoder_state *state,
                        struct sbc_frame *frame, int ch, int blk)
{
      int32_t *x = &state->X[ch][state->position[ch]];
      int16_t *pcm = &frame->pcm_sample[ch][blk * 4];

      /* Input 4 Audio Samples */
      x[40] = x[0] = pcm[3];
      x[41] = x[1] = pcm[2];
      x[42] = x[2] = pcm[1];
      x[43] = x[3] = pcm[0];

      _sbc_analyze_four(x, frame->sb_sample_f[blk][ch]);

      state->position[ch] -= 4;
      if (state->position[ch] < 0)
            state->position[ch] = 36;
}

static inline void _sbc_analyze_eight(const int32_t *in, int32_t *out)
{
      sbc_fixed_t t[8], s[8];

      t[0] = SCALE8_STAGE1( /* Q10 */
            MULA(_sbc_proto_8[0], (in[16] - in[64]), /* Q18 = Q18 * Q0 */
            MULA(_sbc_proto_8[1], (in[32] - in[48]),
            MULA(_sbc_proto_8[2], in[4],
            MULA(_sbc_proto_8[3], in[20],
            MULA(_sbc_proto_8[4], in[36],
            MUL( _sbc_proto_8[5], in[52])))))));

      t[1] = SCALE8_STAGE1(
            MULA(_sbc_proto_8[6], in[2],
            MULA(_sbc_proto_8[7], in[18],
            MULA(_sbc_proto_8[8], in[34],
            MULA(_sbc_proto_8[9], in[50],
            MUL(_sbc_proto_8[10], in[66]))))));

      t[2] = SCALE8_STAGE1(
            MULA(_sbc_proto_8[11], in[1],
            MULA(_sbc_proto_8[12], in[17],
            MULA(_sbc_proto_8[13], in[33],
            MULA(_sbc_proto_8[14], in[49],
            MULA(_sbc_proto_8[15], in[65],
            MULA(_sbc_proto_8[16], in[3],
            MULA(_sbc_proto_8[17], in[19],
            MULA(_sbc_proto_8[18], in[35],
            MULA(_sbc_proto_8[19], in[51],
            MUL( _sbc_proto_8[20], in[67])))))))))));

      t[3] = SCALE8_STAGE1(
            MULA( _sbc_proto_8[21], in[5],
            MULA( _sbc_proto_8[22], in[21],
            MULA( _sbc_proto_8[23], in[37],
            MULA( _sbc_proto_8[24], in[53],
            MULA( _sbc_proto_8[25], in[69],
            MULA(-_sbc_proto_8[15], in[15],
            MULA(-_sbc_proto_8[14], in[31],
            MULA(-_sbc_proto_8[13], in[47],
            MULA(-_sbc_proto_8[12], in[63],
            MUL( -_sbc_proto_8[11], in[79])))))))))));

      t[4] = SCALE8_STAGE1(
            MULA( _sbc_proto_8[26], in[6],
            MULA( _sbc_proto_8[27], in[22],
            MULA( _sbc_proto_8[28], in[38],
            MULA( _sbc_proto_8[29], in[54],
            MULA( _sbc_proto_8[30], in[70],
            MULA(-_sbc_proto_8[10], in[14],
            MULA(-_sbc_proto_8[9], in[30],
            MULA(-_sbc_proto_8[8], in[46],
            MULA(-_sbc_proto_8[7], in[62],
            MUL( -_sbc_proto_8[6], in[78])))))))))));

      t[5] = SCALE8_STAGE1(
            MULA( _sbc_proto_8[31], in[7],
            MULA( _sbc_proto_8[32], in[23],
            MULA( _sbc_proto_8[33], in[39],
            MULA( _sbc_proto_8[34], in[55],
            MULA( _sbc_proto_8[35], in[71],
            MULA(-_sbc_proto_8[20], in[13],
            MULA(-_sbc_proto_8[19], in[29],
            MULA(-_sbc_proto_8[18], in[45],
            MULA(-_sbc_proto_8[17], in[61],
            MUL( -_sbc_proto_8[16], in[77])))))))))));

      t[6] = SCALE8_STAGE1(
            MULA( _sbc_proto_8[36], (in[8] + in[72]),
            MULA( _sbc_proto_8[37], (in[24] + in[56]),
            MULA( _sbc_proto_8[38], in[40],
            MULA(-_sbc_proto_8[39], in[12],
            MULA(-_sbc_proto_8[5], in[28],
            MULA(-_sbc_proto_8[4], in[44],
            MULA(-_sbc_proto_8[3], in[60],
            MUL( -_sbc_proto_8[2], in[76])))))))));

      t[7] = SCALE8_STAGE1(
            MULA( _sbc_proto_8[35], in[9],
            MULA( _sbc_proto_8[34], in[25],
            MULA( _sbc_proto_8[33], in[41],
            MULA( _sbc_proto_8[32], in[57],
            MULA( _sbc_proto_8[31], in[73],
            MULA(-_sbc_proto_8[25], in[11],
            MULA(-_sbc_proto_8[24], in[27],
            MULA(-_sbc_proto_8[23], in[43],
            MULA(-_sbc_proto_8[22], in[59],
            MUL( -_sbc_proto_8[21], in[75])))))))))));

      s[0] = MULA(  _anamatrix8[0], t[0],
            MUL(  _anamatrix8[1], t[6]));
      s[1] = MUL(   _anamatrix8[7], t[1]);
      s[2] = MULA(  _anamatrix8[2], t[2],
            MULA( _anamatrix8[3], t[3],
            MULA( _anamatrix8[4], t[5],
            MUL(  _anamatrix8[5], t[7]))));
      s[3] = MUL(   _anamatrix8[6], t[4]);
      s[4] = MULA(  _anamatrix8[3], t[2],
            MULA(-_anamatrix8[5], t[3],
            MULA(-_anamatrix8[2], t[5],
            MUL( -_anamatrix8[4], t[7]))));
      s[5] = MULA(  _anamatrix8[4], t[2],
            MULA(-_anamatrix8[2], t[3],
            MULA( _anamatrix8[5], t[5],
            MUL(  _anamatrix8[3], t[7]))));
      s[6] = MULA(  _anamatrix8[1], t[0],
            MUL( -_anamatrix8[0], t[6]));
      s[7] = MULA(  _anamatrix8[5], t[2],
            MULA(-_anamatrix8[4], t[3],
            MULA( _anamatrix8[3], t[5],
            MUL( -_anamatrix8[2], t[7]))));

      out[0] = SCALE8_STAGE2( s[0] + s[1] + s[2] + s[3]);
      out[1] = SCALE8_STAGE2( s[1] - s[3] + s[4] + s[6]);
      out[2] = SCALE8_STAGE2( s[1] - s[3] + s[5] - s[6]);
      out[3] = SCALE8_STAGE2(-s[0] + s[1] + s[3] + s[7]);
      out[4] = SCALE8_STAGE2(-s[0] + s[1] + s[3] - s[7]);
      out[5] = SCALE8_STAGE2( s[1] - s[3] - s[5] - s[6]);
      out[6] = SCALE8_STAGE2( s[1] - s[3] - s[4] + s[6]);
      out[7] = SCALE8_STAGE2( s[0] + s[1] - s[2] + s[3]);
}

static inline void sbc_analyze_eight(struct sbc_encoder_state *state,
                              struct sbc_frame *frame, int ch,
                              int blk)
{
      int32_t *x = &state->X[ch][state->position[ch]];
      int16_t *pcm = &frame->pcm_sample[ch][blk * 8];

      /* Input 8 Audio Samples */
      x[80] = x[0] = pcm[7];
      x[81] = x[1] = pcm[6];
      x[82] = x[2] = pcm[5];
      x[83] = x[3] = pcm[4];
      x[84] = x[4] = pcm[3];
      x[85] = x[5] = pcm[2];
      x[86] = x[6] = pcm[1];
      x[87] = x[7] = pcm[0];

      _sbc_analyze_eight(x, frame->sb_sample_f[blk][ch]);

      state->position[ch] -= 8;
      if (state->position[ch] < 0)
            state->position[ch] = 72;
}

static int sbc_analyze_audio(struct sbc_encoder_state *state,
                        struct sbc_frame *frame)
{
      int ch, blk;

      switch (frame->subbands) {
      case 4:
            for (ch = 0; ch < frame->channels; ch++)
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_analyze_four(state, frame, ch, blk);
            return frame->blocks * 4;

      case 8:
            for (ch = 0; ch < frame->channels; ch++)
                  for (blk = 0; blk < frame->blocks; blk++)
                        sbc_analyze_eight(state, frame, ch, blk);
            return frame->blocks * 8;

      default:
            return -EIO;
      }
}

/*
 * Packs the SBC frame from frame into the memory at data. At most len
 * bytes will be used, should more memory be needed an appropriate
 * error code will be returned. Returns the length of the packed frame
 * on success or a negative value on error.
 *
 * The error codes are:
 * -1 Not enough memory reserved
 * -2 Unsupported sampling rate
 * -3 Unsupported number of blocks
 * -4 Unsupported number of subbands
 * -5 Bitpool value out of bounds
 * -99 not implemented
 */

static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
{
      int produced;
      /* Will copy the header parts for CRC-8 calculation here */
      uint8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
      int crc_pos = 0;

      uint16_t audio_sample;

      int ch, sb, blk, bit;   /* channel, subband, block and bit counters */
      int bits[2][8];         /* bits distribution */
      int levels[2][8]; /* levels are derived from that */

      u_int32_t scalefactor[2][8];  /* derived from frame->scale_factor */

      data[0] = SBC_SYNCWORD;

      data[1] = (frame->frequency & 0x03) << 6;

      data[1] |= (frame->block_mode & 0x03) << 4;

      data[1] |= (frame->mode & 0x03) << 2;

      data[1] |= (frame->allocation & 0x01) << 1;

      switch (frame->subbands) {
      case 4:
            /* Nothing to do */
            break;
      case 8:
            data[1] |= 0x01;
            break;
      default:
            return -4;
            break;
      }

      data[2] = frame->bitpool;

      if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) &&
                  frame->bitpool > frame->subbands << 4)
            return -5;

      if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) &&
                  frame->bitpool > frame->subbands << 5)
            return -5;

      /* Can't fill in crc yet */

      produced = 32;

      crc_header[0] = data[1];
      crc_header[1] = data[2];
      crc_pos = 16;

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  frame->scale_factor[ch][sb] = 0;
                  scalefactor[ch][sb] = 2;
                  for (blk = 0; blk < frame->blocks; blk++) {
                        while (scalefactor[ch][sb] < fabs(frame->sb_sample_f[blk][ch][sb])) {
                              frame->scale_factor[ch][sb]++;
                              scalefactor[ch][sb] *= 2;
                        }
                  }
            }
      }

      if (frame->mode == JOINT_STEREO) {
            /* like frame->sb_sample but joint stereo */
            int32_t sb_sample_j[16][2];
            /* scalefactor and scale_factor in joint case */
            u_int32_t scalefactor_j[2];
            uint8_t scale_factor_j[2];

            frame->joint = 0;

            for (sb = 0; sb < frame->subbands - 1; sb++) {
                  scale_factor_j[0] = 0;
                  scalefactor_j[0] = 2;
                  scale_factor_j[1] = 0;
                  scalefactor_j[1] = 2;

                  for (blk = 0; blk < frame->blocks; blk++) {
                        /* Calculate joint stereo signal */
                        sb_sample_j[blk][0] =
                              (frame->sb_sample_f[blk][0][sb] +
                                    frame->sb_sample_f[blk][1][sb]) >> 1;
                        sb_sample_j[blk][1] =
                              (frame->sb_sample_f[blk][0][sb] -
                                    frame->sb_sample_f[blk][1][sb]) >> 1;

                        /* calculate scale_factor_j and scalefactor_j for joint case */
                        while (scalefactor_j[0] < fabs(sb_sample_j[blk][0])) {
                              scale_factor_j[0]++;
                              scalefactor_j[0] *= 2;
                        }
                        while (scalefactor_j[1] < fabs(sb_sample_j[blk][1])) {
                              scale_factor_j[1]++;
                              scalefactor_j[1] *= 2;
                        }
                  }

                  /* decide whether to join this subband */
                  if ((scalefactor[0][sb] + scalefactor[1][sb]) >
                              (scalefactor_j[0] + scalefactor_j[1]) ) {
                        /* use joint stereo for this subband */
                        frame->joint |= 1 << sb;
                        frame->scale_factor[0][sb] = scale_factor_j[0];
                        frame->scale_factor[1][sb] = scale_factor_j[1];
                        scalefactor[0][sb] = scalefactor_j[0];
                        scalefactor[1][sb] = scalefactor_j[1];
                        for (blk = 0; blk < frame->blocks; blk++) {
                              frame->sb_sample_f[blk][0][sb] =
                                          sb_sample_j[blk][0];
                              frame->sb_sample_f[blk][1][sb] =
                                          sb_sample_j[blk][1];
                        }
                  }
            }

            data[4] = 0;
            for (sb = 0; sb < frame->subbands - 1; sb++)
                  data[4] |= ((frame->joint >> sb) & 0x01) << (frame->subbands - 1 - sb);

            crc_header[crc_pos >> 3] = data[4];

            produced += frame->subbands;
            crc_pos += frame->subbands;
      }

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++) {
                  data[produced >> 3] <<= 4;
                  crc_header[crc_pos >> 3] <<= 4;
                  data[produced >> 3] |= frame->scale_factor[ch][sb] & 0x0F;
                  crc_header[crc_pos >> 3] |= frame->scale_factor[ch][sb] & 0x0F;

                  produced += 4;
                  crc_pos += 4;
            }
      }

      /* align the last crc byte */
      if (crc_pos % 8)
            crc_header[crc_pos >> 3] <<= 8 - (crc_pos % 8);

      data[3] = sbc_crc8(crc_header, crc_pos);

      sbc_calculate_bits(frame, bits);

      for (ch = 0; ch < frame->channels; ch++) {
            for (sb = 0; sb < frame->subbands; sb++)
                  levels[ch][sb] = (1 << bits[ch][sb]) - 1;
      }

      for (blk = 0; blk < frame->blocks; blk++) {
            for (ch = 0; ch < frame->channels; ch++) {
                  for (sb = 0; sb < frame->subbands; sb++) {
                        if (levels[ch][sb] > 0) {
                              audio_sample =
                                    (uint16_t) ((((frame->sb_sample_f[blk][ch][sb]*levels[ch][sb]) >>
                                                      (frame->scale_factor[ch][sb] + 1)) +
                                                levels[ch][sb]) >> 1);
                              audio_sample <<= 16 - bits[ch][sb];
                              for (bit = 0; bit < bits[ch][sb]; bit++) {
                                    data[produced >> 3] <<= 1;
                                    if (audio_sample & 0x8000)
                                          data[produced >> 3] |= 0x1;
                                    audio_sample <<= 1;
                                    produced++;
                              }
                        }
                  }
            }
      }

      /* align the last byte */
      if (produced % 8) {
            data[produced >> 3] <<= 8 - (produced % 8);
      }

      return (produced + 7) >> 3;
}

struct sbc_priv {
      int init;
      struct sbc_frame frame;
      struct sbc_decoder_state dec_state;
      struct sbc_encoder_state enc_state;
};

static void sbc_set_defaults(sbc_t *sbc, unsigned long flags)
{
      sbc->frequency = SBC_FREQ_44100;
      sbc->mode = SBC_MODE_STEREO;
      sbc->subbands = SBC_SB_8;
      sbc->blocks = SBC_BLK_16;
      sbc->bitpool = 32;
#if __BYTE_ORDER == __LITTLE_ENDIAN
      sbc->endian = SBC_LE;
#elif __BYTE_ORDER == __BIG_ENDIAN
      sbc->endian = SBC_BE;
#else
#error "Unknown byte order"
#endif
}

int sbc_init(sbc_t *sbc, unsigned long flags)
{
      if (!sbc)
            return -EIO;

      memset(sbc, 0, sizeof(sbc_t));

      sbc->priv = malloc(sizeof(struct sbc_priv));
      if (!sbc->priv)
            return -ENOMEM;

      memset(sbc->priv, 0, sizeof(struct sbc_priv));

      sbc_set_defaults(sbc, flags);

      return 0;
}

int sbc_parse(sbc_t *sbc, void *input, int input_len)
{
      return sbc_decode(sbc, input, input_len, NULL, 0, NULL);
}

int sbc_decode(sbc_t *sbc, void *input, int input_len, void *output,
            int output_len, int *written)
{
      struct sbc_priv *priv;
      char *ptr;
      int i, ch, framelen, samples;

      if (!sbc && !input)
            return -EIO;

      priv = sbc->priv;

      framelen = sbc_unpack_frame(input, &priv->frame, input_len);

      if (!priv->init) {
            sbc_decoder_init(&priv->dec_state, &priv->frame);
            priv->init = 1;

            sbc->frequency = priv->frame.frequency;
            sbc->mode = priv->frame.mode;
            sbc->subbands = priv->frame.subband_mode;
            sbc->blocks = priv->frame.block_mode;
            sbc->allocation = priv->frame.allocation;
            sbc->bitpool = priv->frame.bitpool;

            priv->frame.codesize = sbc_get_codesize(sbc);
            priv->frame.length = sbc_get_frame_length(sbc);
      }

      if (!output)
            return framelen;

      if (written)
            *written = 0;

      samples = sbc_synthesize_audio(&priv->dec_state, &priv->frame);

      ptr = output;

      if (output_len < samples * priv->frame.channels * 2)
            samples = output_len / (priv->frame.channels * 2);

      for (i = 0; i < samples; i++) {
            for (ch = 0; ch < priv->frame.channels; ch++) {
                  int16_t s;
                  s = priv->frame.pcm_sample[ch][i];

#if __BYTE_ORDER == __LITTLE_ENDIAN
                  if (sbc->endian == SBC_BE) {
#elif __BYTE_ORDER == __BIG_ENDIAN
                  if (sbc->endian == SBC_LE) {
#else
#error "Unknown byte order"
#endif
                        *ptr++ = (s & 0xff00) >> 8;
                        *ptr++ = (s & 0x00ff);
                  } else {
                        *ptr++ = (s & 0x00ff);
                        *ptr++ = (s & 0xff00) >> 8;
                  }
            }
      }

      if (written)
            *written = samples * priv->frame.channels * 2;

      return framelen;
}

int sbc_encode(sbc_t *sbc, void *input, int input_len, void *output,
            int output_len, int *written)
{
      struct sbc_priv *priv;
      char *ptr;
      int i, ch, framelen, samples;

      if (!sbc && !input)
            return -EIO;

      priv = sbc->priv;

      if (written)
            *written = 0;

      if (!priv->init) {
            priv->frame.frequency = sbc->frequency;
            priv->frame.mode = sbc->mode;
            priv->frame.channels = sbc->mode == SBC_MODE_MONO ? 1 : 2;
            priv->frame.allocation = sbc->allocation;
            priv->frame.subband_mode = sbc->subbands;
            priv->frame.subbands = sbc->subbands ? 8 : 4;
            priv->frame.block_mode = sbc->blocks;
            priv->frame.blocks = 4 + (sbc->blocks * 4);
            priv->frame.bitpool = sbc->bitpool;
            priv->frame.codesize = sbc_get_codesize(sbc);
            priv->frame.length = sbc_get_frame_length(sbc);

            sbc_encoder_init(&priv->enc_state, &priv->frame);
            priv->init = 1;
      }

      /* input must be large enough to encode a complete frame */
      if (input_len < priv->frame.codesize)
            return 0;

      /* output must be large enough to receive the encoded frame */
      if (!output || output_len < priv->frame.length)
            return -ENOSPC;

      ptr = input;

      for (i = 0; i < priv->frame.subbands * priv->frame.blocks; i++) {
            for (ch = 0; ch < priv->frame.channels; ch++) {
                  int16_t s;
#if __BYTE_ORDER == __LITTLE_ENDIAN
                  if (sbc->endian == SBC_BE)
#elif __BYTE_ORDER == __BIG_ENDIAN
                  if (sbc->endian == SBC_LE)
#else
#error "Unknown byte order"
#endif
                        s = (ptr[0] & 0xff) << 8 | (ptr[1] & 0xff);
                  else
                        s = (ptr[0] & 0xff) | (ptr[1] & 0xff) << 8;
                  ptr += 2;
                  priv->frame.pcm_sample[ch][i] = s;
            }
      }

      samples = sbc_analyze_audio(&priv->enc_state, &priv->frame);

      framelen = sbc_pack_frame(output, &priv->frame, output_len);

      if (written)
            *written = framelen;

      return samples * priv->frame.channels * 2;
}

void sbc_finish(sbc_t *sbc)
{
      if (!sbc)
            return;

      if (sbc->priv)
            free(sbc->priv);

      memset(sbc, 0, sizeof(sbc_t));
}

int sbc_get_frame_length(sbc_t *sbc)
{
      int ret;
      uint8_t subbands, channels, blocks, joint;
      struct sbc_priv *priv;

      priv = sbc->priv;
      if (!priv->init) {
            subbands = sbc->subbands ? 8 : 4;
            blocks = 4 + (sbc->blocks * 4);
            channels = sbc->mode == SBC_MODE_MONO ? 1 : 2;
            joint = sbc->mode == SBC_MODE_JOINT_STEREO ? 1 : 0;
      } else {
            subbands = priv->frame.subbands;
            blocks = priv->frame.blocks;
            channels = priv->frame.channels;
            joint = priv->frame.joint;
      }

      ret = 4 + (4 * subbands * channels) / 8;

      /* This term is not always evenly divide so we round it up */
      if (channels == 1)
            ret += ((blocks * channels * sbc->bitpool) + 7) / 8;
      else
            ret += (((joint ? subbands : 0) + blocks * sbc->bitpool) + 7)
                  / 8;

      return ret;
}

int sbc_get_frame_duration(sbc_t *sbc)
{
      uint8_t subbands, blocks;
      uint16_t frequency;
      struct sbc_priv *priv;

      priv = sbc->priv;
      if (!priv->init) {
            subbands = sbc->subbands ? 8 : 4;
            blocks = 4 + (sbc->blocks * 4);
      } else {
            subbands = priv->frame.subbands;
            blocks = priv->frame.blocks;
      }

      switch (sbc->frequency) {
      case SBC_FREQ_16000:
            frequency = 16000;
            break;

      case SBC_FREQ_32000:
            frequency = 32000;
            break;

      case SBC_FREQ_44100:
            frequency = 44100;
            break;

      case SBC_FREQ_48000:
            frequency = 48000;
            break;
      default:
            return 0;
      }

      return (1000000 * blocks * subbands) / frequency;
}

int sbc_get_codesize(sbc_t *sbc)
{
      uint8_t subbands, channels, blocks;
      struct sbc_priv *priv;

      priv = sbc->priv;
      if (!priv->init) {
            subbands = sbc->subbands ? 8 : 4;
            blocks = 4 + (sbc->blocks * 4);
            channels = sbc->mode == SBC_MODE_MONO ? 1 : 2;
      } else {
            subbands = priv->frame.subbands;
            blocks = priv->frame.blocks;
            channels = priv->frame.channels;
      }

      return subbands * blocks * channels * 2;
}

int sbc_reinit(sbc_t *sbc, unsigned long flags)
{
      struct sbc_priv *priv;

      if (!sbc || !sbc->priv)
            return -EIO;

      priv = sbc->priv;

      if (priv->init == 1)
            memset(sbc->priv, 0, sizeof(struct sbc_priv));

      sbc_set_defaults(sbc, flags);

      return 0;
}

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