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/*
* 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 "libavutil/mem.h"
#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(AC3EncodeContext *s)
{
float fwin[AC3_BLOCK_SIZE];
const float scale = -1.0f;
int32_t *iwin = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*iwin));
if (!iwin)
return AVERROR(ENOMEM);
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->mdct_window = iwin;
s->fdsp = avpriv_alloc_fixed_dsp(s->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;
s->fixed_point = 1;
s->mdct_init = ac3_fixed_mdct_init;
s->allocate_sample_buffers = allocate_sample_buffers;
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_fixed_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,
};
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