LCOV - code coverage report
Current view: top level - libavcodec - ac3enc_fixed.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 37 37 100.0 %
Date: 2017-12-10 21:22:29 Functions: 8 8 100.0 %

          Line data    Source code
       1             : /*
       2             :  * The simplest AC-3 encoder
       3             :  * Copyright (c) 2000 Fabrice Bellard
       4             :  * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
       5             :  * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
       6             :  *
       7             :  * This file is part of FFmpeg.
       8             :  *
       9             :  * FFmpeg is free software; you can redistribute it and/or
      10             :  * modify it under the terms of the GNU Lesser General Public
      11             :  * License as published by the Free Software Foundation; either
      12             :  * version 2.1 of the License, or (at your option) any later version.
      13             :  *
      14             :  * FFmpeg is distributed in the hope that it will be useful,
      15             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      16             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      17             :  * Lesser General Public License for more details.
      18             :  *
      19             :  * You should have received a copy of the GNU Lesser General Public
      20             :  * License along with FFmpeg; if not, write to the Free Software
      21             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      22             :  */
      23             : 
      24             : /**
      25             :  * @file
      26             :  * fixed-point AC-3 encoder.
      27             :  */
      28             : 
      29             : #define FFT_FLOAT 0
      30             : #undef CONFIG_AC3ENC_FLOAT
      31             : #include "internal.h"
      32             : #include "audiodsp.h"
      33             : #include "ac3enc.h"
      34             : #include "eac3enc.h"
      35             : 
      36             : #define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED
      37             : #include "ac3enc_opts_template.c"
      38             : 
      39             : static const AVClass ac3enc_class = {
      40             :     .class_name = "Fixed-Point AC-3 Encoder",
      41             :     .item_name  = av_default_item_name,
      42             :     .option     = ac3_options,
      43             :     .version    = LIBAVUTIL_VERSION_INT,
      44             : };
      45             : 
      46             : /*
      47             :  * Normalize the input samples to use the maximum available precision.
      48             :  * This assumes signed 16-bit input samples.
      49             :  */
      50        4344 : static int normalize_samples(AC3EncodeContext *s)
      51             : {
      52        4344 :     int v = s->ac3dsp.ac3_max_msb_abs_int16(s->windowed_samples, AC3_WINDOW_SIZE);
      53        4344 :     v = 14 - av_log2(v);
      54        4344 :     if (v > 0)
      55        3996 :         s->ac3dsp.ac3_lshift_int16(s->windowed_samples, AC3_WINDOW_SIZE, v);
      56             :     /* +6 to right-shift from 31-bit to 25-bit */
      57        4344 :     return v + 6;
      58             : }
      59             : 
      60             : 
      61             : /*
      62             :  * Scale MDCT coefficients to 25-bit signed fixed-point.
      63             :  */
      64         551 : static void scale_coefficients(AC3EncodeContext *s)
      65             : {
      66             :     int blk, ch;
      67             : 
      68        3857 :     for (blk = 0; blk < s->num_blocks; blk++) {
      69        3306 :         AC3Block *block = &s->blocks[blk];
      70        7650 :         for (ch = 1; ch <= s->channels; ch++) {
      71        8688 :             s->ac3dsp.ac3_rshift_int32(block->mdct_coef[ch], AC3_MAX_COEFS,
      72        4344 :                                        block->coeff_shift[ch]);
      73             :         }
      74             :     }
      75         551 : }
      76             : 
      77        4152 : static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4],
      78             :                                  const int32_t *coef0, const int32_t *coef1,
      79             :                                  int len)
      80             : {
      81        4152 :     s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len);
      82        4152 : }
      83             : 
      84             : /*
      85             :  * Clip MDCT coefficients to allowable range.
      86             :  */
      87        1589 : static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef,
      88             :                               unsigned int len)
      89             : {
      90        1589 :     adsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);
      91        1589 : }
      92             : 
      93             : 
      94             : /*
      95             :  * Calculate a single coupling coordinate.
      96             :  */
      97        9704 : static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
      98             : {
      99        9704 :     if (energy_cpl <= COEF_MAX) {
     100        7882 :         return 1048576;
     101             :     } else {
     102        1822 :         uint64_t coord   = energy_ch / (energy_cpl >> 24);
     103        1822 :         uint32_t coord32 = FFMIN(coord, 1073741824);
     104        1822 :         coord32          = ff_sqrt(coord32) << 9;
     105        1822 :         return FFMIN(coord32, COEF_MAX);
     106             :     }
     107             : }
     108             : 
     109             : 
     110             : #include "ac3enc_template.c"
     111             : 
     112             : 
     113             : /**
     114             :  * Finalize MDCT and free allocated memory.
     115             :  *
     116             :  * @param s  AC-3 encoder private context
     117             :  */
     118           4 : av_cold void ff_ac3_fixed_mdct_end(AC3EncodeContext *s)
     119             : {
     120           4 :     ff_mdct_end(&s->mdct);
     121           4 : }
     122             : 
     123             : 
     124             : /**
     125             :  * Initialize MDCT tables.
     126             :  *
     127             :  * @param s  AC-3 encoder private context
     128             :  * @return   0 on success, negative error code on failure
     129             :  */
     130           4 : av_cold int ff_ac3_fixed_mdct_init(AC3EncodeContext *s)
     131             : {
     132           4 :     int ret = ff_mdct_init(&s->mdct, 9, 0, -1.0);
     133           4 :     s->mdct_window = ff_ac3_window;
     134           4 :     return ret;
     135             : }
     136             : 
     137             : 
     138           4 : static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
     139             : {
     140           4 :     AC3EncodeContext *s = avctx->priv_data;
     141           4 :     s->fixed_point = 1;
     142           4 :     return ff_ac3_encode_init(avctx);
     143             : }
     144             : 
     145             : 
     146             : AVCodec ff_ac3_fixed_encoder = {
     147             :     .name            = "ac3_fixed",
     148             :     .long_name       = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
     149             :     .type            = AVMEDIA_TYPE_AUDIO,
     150             :     .id              = AV_CODEC_ID_AC3,
     151             :     .priv_data_size  = sizeof(AC3EncodeContext),
     152             :     .init            = ac3_fixed_encode_init,
     153             :     .encode2         = ff_ac3_fixed_encode_frame,
     154             :     .close           = ff_ac3_encode_close,
     155             :     .sample_fmts     = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16P,
     156             :                                                       AV_SAMPLE_FMT_NONE },
     157             :     .priv_class      = &ac3enc_class,
     158             :     .channel_layouts = ff_ac3_channel_layouts,
     159             :     .defaults        = ac3_defaults,
     160             : };

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