LCOV - code coverage report
Current view: top level - libavcodec - g722.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 51 51 100.0 %
Date: 2017-12-17 16:07:53 Functions: 5 5 100.0 %

          Line data    Source code
       1             : /*
       2             :  * G.722 ADPCM audio encoder/decoder
       3             :  *
       4             :  * Copyright (c) CMU 1993 Computer Science, Speech Group
       5             :  *                        Chengxiang Lu and Alex Hauptmann
       6             :  * Copyright (c) 2005 Steve Underwood <steveu at coppice.org>
       7             :  * Copyright (c) 2009 Kenan Gillet
       8             :  * Copyright (c) 2010 Martin Storsjo
       9             :  *
      10             :  * This file is part of FFmpeg.
      11             :  *
      12             :  * FFmpeg is free software; you can redistribute it and/or
      13             :  * modify it under the terms of the GNU Lesser General Public
      14             :  * License as published by the Free Software Foundation; either
      15             :  * version 2.1 of the License, or (at your option) any later version.
      16             :  *
      17             :  * FFmpeg is distributed in the hope that it will be useful,
      18             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      19             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      20             :  * Lesser General Public License for more details.
      21             :  *
      22             :  * You should have received a copy of the GNU Lesser General Public
      23             :  * License along with FFmpeg; if not, write to the Free Software
      24             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      25             :  */
      26             : 
      27             : /**
      28             :  * @file
      29             :  * G.722 ADPCM audio codec
      30             :  *
      31             :  * This G.722 decoder is a bit-exact implementation of the ITU G.722
      32             :  * specification for all three specified bitrates - 64000bps, 56000bps
      33             :  * and 48000bps. It passes the ITU tests.
      34             :  *
      35             :  * @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits
      36             :  *       respectively of each byte are ignored.
      37             :  */
      38             : 
      39             : #include "mathops.h"
      40             : #include "g722.h"
      41             : 
      42             : static const int8_t sign_lookup[2] = { -1, 1 };
      43             : 
      44             : static const int16_t inv_log2_table[32] = {
      45             :     2048, 2093, 2139, 2186, 2233, 2282, 2332, 2383,
      46             :     2435, 2489, 2543, 2599, 2656, 2714, 2774, 2834,
      47             :     2896, 2960, 3025, 3091, 3158, 3228, 3298, 3371,
      48             :     3444, 3520, 3597, 3676, 3756, 3838, 3922, 4008
      49             : };
      50             : static const int16_t high_log_factor_step[2] = { 798, -214 };
      51             : const int16_t ff_g722_high_inv_quant[4] = { -926, -202, 926, 202 };
      52             : /**
      53             :  * low_log_factor_step[index] == wl[rl42[index]]
      54             :  */
      55             : static const int16_t low_log_factor_step[16] = {
      56             :      -60, 3042, 1198, 538, 334, 172,  58, -30,
      57             :     3042, 1198,  538, 334, 172,  58, -30, -60
      58             : };
      59             : const int16_t ff_g722_low_inv_quant4[16] = {
      60             :        0, -2557, -1612, -1121,  -786,  -530,  -323,  -150,
      61             :     2557,  1612,  1121,   786,   530,   323,   150,     0
      62             : };
      63             : const int16_t ff_g722_low_inv_quant6[64] = {
      64             :      -17,   -17,   -17,   -17, -3101, -2738, -2376, -2088,
      65             :    -1873, -1689, -1535, -1399, -1279, -1170, -1072,  -982,
      66             :     -899,  -822,  -750,  -682,  -618,  -558,  -501,  -447,
      67             :     -396,  -347,  -300,  -254,  -211,  -170,  -130,   -91,
      68             :     3101,  2738,  2376,  2088,  1873,  1689,  1535,  1399,
      69             :     1279,  1170,  1072,   982,   899,   822,   750,   682,
      70             :      618,   558,   501,   447,   396,   347,   300,   254,
      71             :      211,   170,   130,    91,    54,    17,   -54,   -17
      72             : };
      73             : 
      74      532652 : static inline void s_zero(int cur_diff, struct G722Band *band)
      75             : {
      76      532652 :     int s_zero = 0;
      77             : 
      78             :     #define ACCUM(k, x, d) do { \
      79             :             int tmp = x; \
      80             :             band->zero_mem[k] = ((band->zero_mem[k] * 255) >> 8) + \
      81             :                d*((band->diff_mem[k]^cur_diff) < 0 ? -128 : 128); \
      82             :             band->diff_mem[k] = tmp; \
      83             :             s_zero += (tmp * band->zero_mem[k]) >> 15; \
      84             :         } while (0)
      85      532652 :     if (cur_diff) {
      86      470786 :         ACCUM(5, band->diff_mem[4], 1);
      87      470786 :         ACCUM(4, band->diff_mem[3], 1);
      88      470786 :         ACCUM(3, band->diff_mem[2], 1);
      89      470786 :         ACCUM(2, band->diff_mem[1], 1);
      90      470786 :         ACCUM(1, band->diff_mem[0], 1);
      91      470786 :         ACCUM(0, cur_diff * 2, 1);
      92             :     } else {
      93       61866 :         ACCUM(5, band->diff_mem[4], 0);
      94       61866 :         ACCUM(4, band->diff_mem[3], 0);
      95       61866 :         ACCUM(3, band->diff_mem[2], 0);
      96       61866 :         ACCUM(2, band->diff_mem[1], 0);
      97       61866 :         ACCUM(1, band->diff_mem[0], 0);
      98       61866 :         ACCUM(0, cur_diff * 2, 0);
      99             :     }
     100             :     #undef ACCUM
     101      532652 :     band->s_zero = s_zero;
     102      532652 : }
     103             : 
     104             : /**
     105             :  * adaptive predictor
     106             :  *
     107             :  * @param cur_diff the dequantized and scaled delta calculated from the
     108             :  *                 current codeword
     109             :  */
     110      532652 : static void do_adaptive_prediction(struct G722Band *band, const int cur_diff)
     111             : {
     112             :     int sg[2], limit, cur_qtzd_reconst;
     113             : 
     114      532652 :     const int cur_part_reconst = band->s_zero + cur_diff < 0;
     115             : 
     116      532652 :     sg[0] = sign_lookup[cur_part_reconst != band->part_reconst_mem[0]];
     117      532652 :     sg[1] = sign_lookup[cur_part_reconst == band->part_reconst_mem[1]];
     118      532652 :     band->part_reconst_mem[1] = band->part_reconst_mem[0];
     119      532652 :     band->part_reconst_mem[0] = cur_part_reconst;
     120             : 
     121     1597956 :     band->pole_mem[1] = av_clip((sg[0] * av_clip(band->pole_mem[0], -8191, 8191) >> 5) +
     122     1065304 :                                 (sg[1] * 128) + (band->pole_mem[1] * 127 >> 7), -12288, 12288);
     123             : 
     124      532652 :     limit = 15360 - band->pole_mem[1];
     125      532652 :     band->pole_mem[0] = av_clip(-192 * sg[0] + (band->pole_mem[0] * 255 >> 8), -limit, limit);
     126             : 
     127      532652 :     s_zero(cur_diff, band);
     128             : 
     129      532652 :     cur_qtzd_reconst = av_clip_int16((band->s_predictor + cur_diff) * 2);
     130     1597956 :     band->s_predictor = av_clip_int16(band->s_zero +
     131      532652 :                                       (band->pole_mem[0] * cur_qtzd_reconst >> 15) +
     132      532652 :                                       (band->pole_mem[1] * band->prev_qtzd_reconst >> 15));
     133      532652 :     band->prev_qtzd_reconst = cur_qtzd_reconst;
     134      532652 : }
     135             : 
     136      532652 : static inline int linear_scale_factor(const int log_factor)
     137             : {
     138      532652 :     const int wd1 = inv_log2_table[(log_factor >> 6) & 31];
     139      532652 :     const int shift = log_factor >> 11;
     140      532652 :     return shift < 0 ? wd1 >> -shift : wd1 << shift;
     141             : }
     142             : 
     143      266326 : void ff_g722_update_low_predictor(struct G722Band *band, const int ilow)
     144             : {
     145      266326 :     do_adaptive_prediction(band,
     146      266326 :                            band->scale_factor * ff_g722_low_inv_quant4[ilow] >> 10);
     147             : 
     148             :     // quantizer adaptation
     149      532652 :     band->log_factor   = av_clip((band->log_factor * 127 >> 7) +
     150      266326 :                                  low_log_factor_step[ilow], 0, 18432);
     151      266326 :     band->scale_factor = linear_scale_factor(band->log_factor - (8 << 11));
     152      266326 : }
     153             : 
     154      266326 : void ff_g722_update_high_predictor(struct G722Band *band, const int dhigh,
     155             :                                   const int ihigh)
     156             : {
     157      266326 :     do_adaptive_prediction(band, dhigh);
     158             : 
     159             :     // quantizer adaptation
     160      532652 :     band->log_factor   = av_clip((band->log_factor * 127 >> 7) +
     161      266326 :                                  high_log_factor_step[ihigh&1], 0, 22528);
     162      266326 :     band->scale_factor = linear_scale_factor(band->log_factor - (10 << 11));
     163      266326 : }

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