/*
  * AC-3 encoder float/fixed template
  * Copyright (c) 2000 Fabrice Bellard
  * Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com>
  * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg 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.
  *

  * FFmpeg 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 FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * AC-3 encoder float/fixed template
  */
 
 #include <stdint.h>
 

 #include "libavutil/attributes.h"

 #include "libavutil/internal.h"

 
 #include "audiodsp.h"

 #include "internal.h"
 #include "ac3enc.h"
 #include "eac3enc.h"

 int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s)
 {
     int ch;
 
     FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE *
                      sizeof(*s->windowed_samples), alloc_fail);

     FF_ALLOC_ARRAY_OR_GOTO(s->avctx, s->planar_samples, s->channels, sizeof(*s->planar_samples),

                      alloc_fail);
     for (ch = 0; ch < s->channels; ch++) {
         FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch],
                           (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
                           alloc_fail);
     }
 
     return 0;
 alloc_fail:
     return AVERROR(ENOMEM);
 }
 
 

 /*

  * Copy input samples.

  * Channels are reordered from FFmpeg's default order to AC-3 order.

  */

 static void copy_input_samples(AC3EncodeContext *s, SampleType **samples)

 {

     int ch;

     /* copy and remap input samples */

     for (ch = 0; ch < s->channels; ch++) {
         /* copy last 256 samples of previous frame to the start of the current frame */

         memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_BLOCK_SIZE * s->num_blocks],

                AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
 

         /* copy new samples for current frame */
         memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE],
                samples[s->channel_map[ch]],
                AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0]));

     }
 }
 
 

 /*

  * Apply the MDCT to input samples to generate frequency coefficients.
  * This applies the KBD window and normalizes the input to reduce precision
  * loss due to fixed-point calculations.
  */

 static void apply_mdct(AC3EncodeContext *s)

 {
     int blk, ch;
 
     for (ch = 0; ch < s->channels; ch++) {

         for (blk = 0; blk < s->num_blocks; blk++) {

             AC3Block *block = &s->blocks[blk];
             const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
 

 #if CONFIG_AC3ENC_FLOAT

             s->fdsp->vector_fmul(s->windowed_samples, input_samples,

                                 s->mdct_window, AC3_WINDOW_SIZE);

 #else

             s->ac3dsp.apply_window_int16(s->windowed_samples, input_samples,
                                          s->mdct_window, AC3_WINDOW_SIZE);

 
             if (s->fixed_point)

                 block->coeff_shift[ch+1] = normalize_samples(s);

 #endif

             s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1],
                                s->windowed_samples);

         }
     }
 }
 
 

 /*

  * Calculate coupling channel and coupling coordinates.
  */

 static void apply_channel_coupling(AC3EncodeContext *s)

 {

     LOCAL_ALIGNED_16(CoefType, cpl_coords,      [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);

 #if CONFIG_AC3ENC_FLOAT
     LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);

 #else
     int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords;
 #endif

     int av_uninit(blk), ch, bnd, i, j;

     CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}};

     int cpl_start, num_cpl_coefs;

 
     memset(cpl_coords,       0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));

 #if CONFIG_AC3ENC_FLOAT
     memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
 #endif

     /* align start to 16-byte boundary. align length to multiple of 32.
         note: coupling start bin % 4 will always be 1 */
     cpl_start     = s->start_freq[CPL_CH] - 1;
     num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32);
     cpl_start     = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs;
 

     /* calculate coupling channel from fbw channels */

     for (blk = 0; blk < s->num_blocks; blk++) {

         AC3Block *block = &s->blocks[blk];

         CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start];

         if (!block->cpl_in_use)
             continue;

         memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef));

         for (ch = 1; ch <= s->fbw_channels; ch++) {

             CoefType *ch_coef = &block->mdct_coef[ch][cpl_start];

             if (!block->channel_in_cpl[ch])
                 continue;
             for (i = 0; i < num_cpl_coefs; i++)
                 cpl_coef[i] += ch_coef[i];
         }
 

         /* coefficients must be clipped in order to be encoded */

         clip_coefficients(&s->adsp, cpl_coef, num_cpl_coefs);

     }
 
     /* calculate energy in each band in coupling channel and each fbw channel */
     /* TODO: possibly use SIMD to speed up energy calculation */
     bnd = 0;
     i = s->start_freq[CPL_CH];
     while (i < s->cpl_end_freq) {
         int band_size = s->cpl_band_sizes[bnd];
         for (ch = CPL_CH; ch <= s->fbw_channels; ch++) {

             for (blk = 0; blk < s->num_blocks; blk++) {

                 AC3Block *block = &s->blocks[blk];
                 if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch]))
                     continue;
                 for (j = 0; j < band_size; j++) {
                     CoefType v = block->mdct_coef[ch][i+j];
                     MAC_COEF(energy[blk][ch][bnd], v, v);
                 }
             }
         }
         i += band_size;
         bnd++;
     }
 

     /* calculate coupling coordinates for all blocks for all channels */
     for (blk = 0; blk < s->num_blocks; blk++) {
         AC3Block *block  = &s->blocks[blk];
         if (!block->cpl_in_use)
             continue;
         for (ch = 1; ch <= s->fbw_channels; ch++) {
             if (!block->channel_in_cpl[ch])
                 continue;
             for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
                 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
                                                           energy[blk][CPL_CH][bnd]);
             }
         }
     }
 

     /* determine which blocks to send new coupling coordinates for */

     for (blk = 0; blk < s->num_blocks; blk++) {

         AC3Block *block  = &s->blocks[blk];
         AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
 

         memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords));
 

         if (block->cpl_in_use) {
             /* send new coordinates if this is the first block, if previous
              * block did not use coupling but this block does, the channels
              * using coupling has changed from the previous block, or the
              * coordinate difference from the last block for any channel is
              * greater than a threshold value. */

             if (blk == 0 || !block0->cpl_in_use) {
                 for (ch = 1; ch <= s->fbw_channels; ch++)
                     block->new_cpl_coords[ch] = 1;

             } else {
                 for (ch = 1; ch <= s->fbw_channels; ch++) {

                     if (!block->channel_in_cpl[ch])
                         continue;
                     if (!block0->channel_in_cpl[ch]) {

                         block->new_cpl_coords[ch] = 1;

                     } else {
                         CoefSumType coord_diff = 0;
                         for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {

                             coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] -
                                                 cpl_coords[blk  ][ch][bnd]);

                         }
                         coord_diff /= s->num_cpl_bands;

                         if (coord_diff > NEW_CPL_COORD_THRESHOLD)

                             block->new_cpl_coords[ch] = 1;

                     }
                 }
             }
         }
     }
 
     /* calculate final coupling coordinates, taking into account reusing of
        coordinates in successive blocks */
     for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
         blk = 0;

         while (blk < s->num_blocks) {

             int av_uninit(blk1);

             AC3Block *block  = &s->blocks[blk];
 
             if (!block->cpl_in_use) {
                 blk++;
                 continue;
             }
 
             for (ch = 1; ch <= s->fbw_channels; ch++) {

                 CoefSumType energy_ch, energy_cpl;

                 if (!block->channel_in_cpl[ch])
                     continue;

                 energy_cpl = energy[blk][CPL_CH][bnd];

                 energy_ch = energy[blk][ch][bnd];
                 blk1 = blk+1;

                 while (blk1 < s->num_blocks && !s->blocks[blk1].new_cpl_coords[ch]) {

                     if (s->blocks[blk1].cpl_in_use) {
                         energy_cpl += energy[blk1][CPL_CH][bnd];

                         energy_ch += energy[blk1][ch][bnd];

                     }

                     blk1++;
                 }
                 cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl);
             }
             blk = blk1;
         }
     }
 
     /* calculate exponents/mantissas for coupling coordinates */

     for (blk = 0; blk < s->num_blocks; blk++) {

         AC3Block *block = &s->blocks[blk];

         if (!block->cpl_in_use)

             continue;
 

 #if CONFIG_AC3ENC_FLOAT

         s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1],
                                    cpl_coords[blk][1],
                                    s->fbw_channels * 16);

 #endif

         s->ac3dsp.extract_exponents(block->cpl_coord_exp[1],
                                     fixed_cpl_coords[blk][1],
                                     s->fbw_channels * 16);
 
         for (ch = 1; ch <= s->fbw_channels; ch++) {
             int bnd, min_exp, max_exp, master_exp;
 

             if (!block->new_cpl_coords[ch])
                 continue;
 

             /* determine master exponent */
             min_exp = max_exp = block->cpl_coord_exp[ch][0];
             for (bnd = 1; bnd < s->num_cpl_bands; bnd++) {
                 int exp = block->cpl_coord_exp[ch][bnd];
                 min_exp = FFMIN(exp, min_exp);
                 max_exp = FFMAX(exp, max_exp);
             }
             master_exp = ((max_exp - 15) + 2) / 3;
             master_exp = FFMAX(master_exp, 0);
             while (min_exp < master_exp * 3)
                 master_exp--;
             for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
                 block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] -
                                                         master_exp * 3, 0, 15);
             }
             block->cpl_master_exp[ch] = master_exp;
 
             /* quantize mantissas */
             for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
                 int cpl_exp  = block->cpl_coord_exp[ch][bnd];
                 int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24;
                 if (cpl_exp == 15)
                     cpl_mant >>= 1;
                 else
                     cpl_mant -= 16;
 
                 block->cpl_coord_mant[ch][bnd] = cpl_mant;
             }
         }
     }
 
     if (CONFIG_EAC3_ENCODER && s->eac3)
         ff_eac3_set_cpl_states(s);
 }
 
 

 /*

  * Determine rematrixing flags for each block and band.
  */

 static void compute_rematrixing_strategy(AC3EncodeContext *s)

 {
     int nb_coefs;

     int blk, bnd;

     AC3Block *block, *block0 = NULL;

 
     if (s->channel_mode != AC3_CHMODE_STEREO)
         return;
 

     for (blk = 0; blk < s->num_blocks; blk++) {

         block = &s->blocks[blk];
         block->new_rematrixing_strategy = !blk;
 
         block->num_rematrixing_bands = 4;
         if (block->cpl_in_use) {
             block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61);
             block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37);
             if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands)
                 block->new_rematrixing_strategy = 1;
         }
         nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
 

         if (!s->rematrixing_enabled) {
             block0 = block;
             continue;
         }
 

         for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {

             /* calculate sum of squared coeffs for one band in one block */

             int start = ff_ac3_rematrix_band_tab[bnd];
             int end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);

             CoefSumType sum[4];
             sum_square_butterfly(s, sum, block->mdct_coef[1] + start,
                                  block->mdct_coef[2] + start, end - start);

 
             /* compare sums to determine if rematrixing will be used for this band */
             if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1]))
                 block->rematrixing_flags[bnd] = 1;
             else
                 block->rematrixing_flags[bnd] = 0;
 
             /* determine if new rematrixing flags will be sent */
             if (blk &&
                 block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) {
                 block->new_rematrixing_strategy = 1;
             }
         }
         block0 = block;
     }
 }

 int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt,
                            const AVFrame *frame, int *got_packet_ptr)

 {
     AC3EncodeContext *s = avctx->priv_data;
     int ret;
 

     if (s->options.allow_per_frame_metadata) {

         ret = ff_ac3_validate_metadata(s);

         if (ret)
             return ret;
     }
 
     if (s->bit_alloc.sr_code == 1 || s->eac3)
         ff_ac3_adjust_frame_size(s);
 

     copy_input_samples(s, (SampleType **)frame->extended_data);

 
     apply_mdct(s);
 

     if (s->fixed_point)
         scale_coefficients(s);
 

     clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1],

                       AC3_MAX_COEFS * s->num_blocks * s->channels);

 
     s->cpl_on = s->cpl_enabled;
     ff_ac3_compute_coupling_strategy(s);
 
     if (s->cpl_on)
         apply_channel_coupling(s);
 
     compute_rematrixing_strategy(s);
 

     if (!s->fixed_point)
         scale_coefficients(s);
 

     ff_ac3_apply_rematrixing(s);
 
     ff_ac3_process_exponents(s);
 
     ret = ff_ac3_compute_bit_allocation(s);
     if (ret) {
         av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
         return ret;
     }
 

     ff_ac3_group_exponents(s);
 

     ff_ac3_quantize_mantissas(s);
 

     if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size, 0)) < 0)

         return ret;
     ff_ac3_output_frame(s, avpkt->data);

     if (frame->pts != AV_NOPTS_VALUE)

         avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->initial_padding);

 
     *got_packet_ptr = 1;
     return 0;

 }