func: int ff_wma_init(AVCodecContext *avctx, int flags2)
  
  {
  
      WMACodecContext *s = avctx->priv_data;
  
      int i;
  
      float bps1, high_freq;
  
      volatile float bps;
  
      int sample_rate1;
  
      int coef_vlc_table;
  
  
  
      if (   avctx->sample_rate <= 0 || avctx->sample_rate > 50000
  
          || avctx->channels    <= 0 || avctx->channels    > 2
  
          || avctx->bit_rate    <= 0)
  
          return -1;
  
  
  
      ff_fmt_convert_init(&s->fmt_conv, avctx);
  
      avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
  
  
  
      if (avctx->codec->id == AV_CODEC_ID_WMAV1) {
  
          s->version = 1;
  
      } else {
  
          s->version = 2;
  
  
  
  
      /* compute MDCT block size */
  
      s->frame_len_bits = ff_wma_get_frame_len_bits(avctx->sample_rate,
  
                                                    s->version, 0);
  
      s->next_block_len_bits = s->frame_len_bits;
  
      s->prev_block_len_bits = s->frame_len_bits;
  
      s->block_len_bits      = s->frame_len_bits;
  
  
  
      s->frame_len = 1 << s->frame_len_bits;
  
      if (s->use_variable_block_len) {
  
          int nb_max, nb;
  
          nb = ((flags2 >> 3) & 3) + 1;
  
          if ((avctx->bit_rate / avctx->channels) >= 32000)
  
              nb += 2;
  
          nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
  
          if (nb > nb_max)
  
              nb = nb_max;
  
          s->nb_block_sizes = nb + 1;
  
      } else {
  
          s->nb_block_sizes = 1;
  
  
  
  
      /* init rate dependent parameters */
  
      s->use_noise_coding = 1;
  
      high_freq = avctx->sample_rate * 0.5;
  
  
  
      /* if version 2, then the rates are normalized */
  
      sample_rate1 = avctx->sample_rate;
  
      if (s->version == 2) {
  
          if (sample_rate1 >= 44100) {
  
              sample_rate1 = 44100;
  
          } else if (sample_rate1 >= 22050) {
  
              sample_rate1 = 22050;
  
          } else if (sample_rate1 >= 16000) {
  
              sample_rate1 = 16000;
  
          } else if (sample_rate1 >= 11025) {
  
              sample_rate1 = 11025;
  
          } else if (sample_rate1 >= 8000) {
  
              sample_rate1 = 8000;
  
  
  
  
  
      bps = (float)avctx->bit_rate / (float)(avctx->channels * avctx->sample_rate);
  
      s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
  
  
  
  
  
  
  
      /* compute high frequency value and choose if noise coding should
  
         be activated */
  
      bps1 = bps;
  
      if (avctx->channels == 2)
  
          bps1 = bps * 1.6;
  
      if (sample_rate1 == 44100) {
  
          if (bps1 >= 0.61) {
  
              s->use_noise_coding = 0;
  
          } else {
  
              high_freq = high_freq * 0.4;
  
  
      } else if (sample_rate1 == 22050) {
  
          if (bps1 >= 1.16) {
  
              s->use_noise_coding = 0;
  
          } else if (bps1 >= 0.72) {
  
              high_freq = high_freq * 0.7;
  
          } else {
  
              high_freq = high_freq * 0.6;
  
  
      } else if (sample_rate1 == 16000) {
  
          if (bps > 0.5) {
  
              high_freq = high_freq * 0.5;
  
          } else {
  
              high_freq = high_freq * 0.3;
  
  
      } else if (sample_rate1 == 11025) {
  
          high_freq = high_freq * 0.7;
  
      } else if (sample_rate1 == 8000) {
  
          if (bps <= 0.625) {
  
              high_freq = high_freq * 0.5;
  
          } else if (bps > 0.75) {
  
              s->use_noise_coding = 0;
  
          } else {
  
              high_freq = high_freq * 0.65;
  
  
      } else {
  
          if (bps >= 0.8) {
  
              high_freq = high_freq * 0.75;
  
          } else if (bps >= 0.6) {
  
              high_freq = high_freq * 0.6;
  
          } else {
  
              high_freq = high_freq * 0.5;
  
  
  
      av_dlog(s->avctx, "flags2=0x%x\n", flags2);
  
      av_dlog(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
  
              s->version, avctx->channels, avctx->sample_rate, avctx->bit_rate,
  
              avctx->block_align);
  
      av_dlog(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
  
              bps, bps1, high_freq, s->byte_offset_bits);
  
      av_dlog(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
  
              s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
  
  
  
      /* compute the scale factor band sizes for each MDCT block size */
  
      {
  
          int a, b, pos, lpos, k, block_len, i, j, n;
  
          const uint8_t *table;
  
  
  
          if (s->version == 1) {
  
              s->coefs_start = 3;
  
          } else {
  
              s->coefs_start = 0;
  
  
          for (k = 0; k < s->nb_block_sizes; k++) {
  
              block_len = s->frame_len >> k;
  
  
  
              if (s->version == 1) {
  
                  lpos = 0;
  
                  for (i = 0; i < 25; i++) {
  
                      a = ff_wma_critical_freqs[i];
  
                      b = avctx->sample_rate;
  
                      pos = ((block_len * 2 * a) + (b >> 1)) / b;
  
                      if (pos > block_len)
  
                          pos = block_len;
  
                      s->exponent_bands[0][i] = pos - lpos;
  
                      if (pos >= block_len) {
  
                          i++;
  
                          break;
  
  
                      lpos = pos;
  
  
                  s->exponent_sizes[0] = i;
  
              } else {
  
                  /* hardcoded tables */
  
                  table = NULL;
  
                  a = s->frame_len_bits - BLOCK_MIN_BITS - k;
  
                  if (a < 3) {
  
                      if (avctx->sample_rate >= 44100) {
  
                          table = exponent_band_44100[a];
  
                      } else if (avctx->sample_rate >= 32000) {
  
                          table = exponent_band_32000[a];
  
                      } else if (avctx->sample_rate >= 22050) {
  
                          table = exponent_band_22050[a];
  
  
  
                  if (table) {
  
                      n = *table++;
  
                      for (i = 0; i < n; i++)
  
                          s->exponent_bands[k][i] = table[i];
  
                      s->exponent_sizes[k] = n;
  
                  } else {
  
                      j = 0;
  
                      lpos = 0;
  
                      for (i = 0; i < 25; i++) {
  
                          a = ff_wma_critical_freqs[i];
  
                          b = avctx->sample_rate;
  
                          pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
  
                          pos <<= 2;
  
                          if (pos > block_len)
  
                              pos = block_len;
  
                          if (pos > lpos)
  
                              s->exponent_bands[k][j++] = pos - lpos;
  
                          if (pos >= block_len)
  
                              break;
  
                          lpos = pos;
  
  
                      s->exponent_sizes[k] = j;
  
  
  
  
  
              /* max number of coefs */
  
              s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
  
              /* high freq computation */
  
              s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
  
                                            avctx->sample_rate + 0.5);
  
              n = s->exponent_sizes[k];
  
              j = 0;
  
              pos = 0;
  
              for (i = 0; i < n; i++) {
  
                  int start, end;
  
                  start = pos;
  
                  pos += s->exponent_bands[k][i];
  
                  end = pos;
  
                  if (start < s->high_band_start[k])
  
                      start = s->high_band_start[k];
  
                  if (end > s->coefs_end[k])
  
                      end = s->coefs_end[k];
  
                  if (end > start)
  
                      s->exponent_high_bands[k][j++] = end - start;
  
  
              s->exponent_high_sizes[k] = j;
  
  #if 0
  
              tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
  
                      s->frame_len >> k,
  
                      s->coefs_end[k],
  
                      s->high_band_start[k],
  
                      s->exponent_high_sizes[k]);
  
              for (j = 0; j < s->exponent_high_sizes[k]; j++)
  
                  tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
  
              tprintf(s->avctx, "\n");
  
  #endif
  
  
  
  
  
  #ifdef TRACE
  
      {
  
          int i, j;
  
          for (i = 0; i < s->nb_block_sizes; i++) {
  
              tprintf(s->avctx, "%5d: n=%2d:",
  
                      s->frame_len >> i,
  
                      s->exponent_sizes[i]);
  
              for (j = 0; j < s->exponent_sizes[i]; j++)
  
                  tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
  
              tprintf(s->avctx, "\n");
  
  
  
  #endif
  
  
  
      /* init MDCT windows : simple sinus window */
  
      for (i = 0; i < s->nb_block_sizes; i++) {
  
          ff_init_ff_sine_windows(s->frame_len_bits - i);
  
          s->windows[i] = ff_sine_windows[s->frame_len_bits - i];
  
  
  
  
      s->reset_block_lengths = 1;
  
  
  
      if (s->use_noise_coding) {
  
  
  
          /* init the noise generator */
  
          if (s->use_exp_vlc) {
  
              s->noise_mult = 0.02;
  
          } else {
  
              s->noise_mult = 0.04;
  
  
  
  
  #ifdef TRACE
  
          for (i = 0; i < NOISE_TAB_SIZE; i++)
  
              s->noise_table[i] = 1.0 * s->noise_mult;
  
  #else
  
          {
  
              unsigned int seed;
  
              float norm;
  
              seed = 1;
  
              norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
  
              for (i = 0; i < NOISE_TAB_SIZE; i++) {
  
                  seed = seed * 314159 + 1;
  
                  s->noise_table[i] = (float)((int)seed) * norm;
  
  
  
  #endif
  
  
  
  
      /* choose the VLC tables for the coefficients */
  
      coef_vlc_table = 2;
  
      if (avctx->sample_rate >= 32000) {
  
          if (bps1 < 0.72) {
  
              coef_vlc_table = 0;
  
          } else if (bps1 < 1.16) {
  
              coef_vlc_table = 1;
  
  
  
      s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
  
      s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
  
      init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
  
                    s->coef_vlcs[0]);
  
      init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
  
                    s->coef_vlcs[1]);
  
  
  
      return 0;
  