/* * The simplest AC-3 encoder * Copyright (c) 2000 Fabrice Bellard * Copyright (c) 2006-2010 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 * fixed-point AC-3 encoder. */ #define AC3ENC_FLOAT 0#include "audiodsp.h"#include "ac3enc.h"#include "codec_internal.h"#include "eac3enc.h"#include "kbdwin.h" static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4],                                 const int32_t *coef0, const int32_t *coef1,                                 int len){    s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len);} /* * Clip MDCT coefficients to allowable range. */static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef,                              unsigned int len){    adsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);}  /* * Calculate a single coupling coordinate. */static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl){    if (energy_cpl <= COEF_MAX) {        return 1048576;    } else {        uint64_t coord   = energy_ch / (energy_cpl >> 24);        uint32_t coord32 = FFMIN(coord, 1073741824);        coord32          = ff_sqrt(coord32) << 9;        return FFMIN(coord32, COEF_MAX);    }} #include "ac3enc_template.c" /** * Initialize MDCT tables. * * @param s  AC-3 encoder private context * @return   0 on success, negative error code on failure */static av_cold int ac3_fixed_mdct_init(AVCodecContext *avctx, AC3EncodeContext *s){    float fwin[AC3_BLOCK_SIZE];    const float scale = -1.0f;     int32_t *iwin = s->mdct_window_fixed;     ff_kbd_window_init(fwin, 5.0, AC3_BLOCK_SIZE);    for (int i = 0; i < AC3_BLOCK_SIZE; i++)        iwin[i] = lrintf(fwin[i] * (1 << 22));     s->fdsp = avpriv_alloc_fixed_dsp(avctx->flags & AV_CODEC_FLAG_BITEXACT);    if (!s->fdsp)        return AVERROR(ENOMEM);     return av_tx_init(&s->tx, &s->tx_fn, AV_TX_INT32_MDCT, 0,                      AC3_BLOCK_SIZE, &scale, 0);}  static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx){    AC3EncodeContext *s = avctx->priv_data;    int ret;     s->fixed_point = 1;    s->encode_frame            = encode_frame;     ret = ac3_fixed_mdct_init(avctx, s);    if (ret < 0)        return ret;     return ff_ac3_encode_init(avctx);}  const FFCodec ff_ac3_fixed_encoder = {    .p.name          = "ac3_fixed",    CODEC_LONG_NAME("ATSC A/52A (AC-3)"),    .p.type          = AVMEDIA_TYPE_AUDIO,    .p.id            = AV_CODEC_ID_AC3,    .p.capabilities  = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,    .priv_data_size  = sizeof(AC3EncodeContext),    .init            = ac3_fixed_encode_init,    FF_CODEC_ENCODE_CB(ff_ac3_encode_frame),    .close           = ff_ac3_encode_close,    .p.sample_fmts   = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32P,                                                      AV_SAMPLE_FMT_NONE },    .p.priv_class    = &ff_ac3enc_class,    .caps_internal   = FF_CODEC_CAP_INIT_CLEANUP,    .p.supported_samplerates = ff_ac3_sample_rate_tab,    .p.ch_layouts    = ff_ac3_ch_layouts,    .defaults        = ff_ac3_enc_defaults,};