mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-25 00:32:31 +00:00
132 lines
3.9 KiB
C
132 lines
3.9 KiB
C
/*
|
|
* 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
|
|
* floating-point AC-3 encoder.
|
|
*/
|
|
|
|
#define AC3ENC_FLOAT 1
|
|
#include "audiodsp.h"
|
|
#include "ac3enc.h"
|
|
#include "codec_internal.h"
|
|
#include "eac3enc.h"
|
|
#include "kbdwin.h"
|
|
|
|
|
|
/*
|
|
* Scale MDCT coefficients from float to 24-bit fixed-point.
|
|
*/
|
|
static void scale_coefficients(AC3EncodeContext *s)
|
|
{
|
|
int chan_size = AC3_MAX_COEFS * s->num_blocks;
|
|
int cpl = s->cpl_on;
|
|
s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
|
|
s->mdct_coef_buffer + (chan_size * !cpl),
|
|
chan_size * (s->channels + cpl));
|
|
}
|
|
|
|
|
|
/*
|
|
* Clip MDCT coefficients to allowable range.
|
|
*/
|
|
static void clip_coefficients(AudioDSPContext *adsp, float *coef,
|
|
unsigned int len)
|
|
{
|
|
adsp->vector_clipf(coef, coef, len, COEF_MIN, COEF_MAX);
|
|
}
|
|
|
|
|
|
/*
|
|
* Calculate a single coupling coordinate.
|
|
*/
|
|
static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
|
|
{
|
|
float coord = 0.125;
|
|
if (energy_cpl > 0)
|
|
coord *= sqrtf(energy_ch / energy_cpl);
|
|
return FFMIN(coord, COEF_MAX);
|
|
}
|
|
|
|
static void sum_square_butterfly(AC3EncodeContext *s, float sum[4],
|
|
const float *coef0, const float *coef1,
|
|
int len)
|
|
{
|
|
s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len);
|
|
}
|
|
|
|
#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_float_mdct_init(AC3EncodeContext *s)
|
|
{
|
|
const float scale = -2.0 / AC3_WINDOW_SIZE;
|
|
|
|
ff_kbd_window_init(s->mdct_window_float, 5.0, AC3_BLOCK_SIZE);
|
|
|
|
return av_tx_init(&s->tx, &s->tx_fn, AV_TX_FLOAT_MDCT, 0,
|
|
AC3_BLOCK_SIZE, &scale, 0);
|
|
}
|
|
|
|
|
|
av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx)
|
|
{
|
|
AC3EncodeContext *s = avctx->priv_data;
|
|
int ret;
|
|
|
|
s->encode_frame = encode_frame;
|
|
s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
|
|
if (!s->fdsp)
|
|
return AVERROR(ENOMEM);
|
|
|
|
ret = ac3_float_mdct_init(s);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
return ff_ac3_encode_init(avctx);
|
|
}
|
|
|
|
const FFCodec ff_ac3_encoder = {
|
|
.p.name = "ac3",
|
|
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 = ff_ac3_float_encode_init,
|
|
FF_CODEC_ENCODE_CB(ff_ac3_encode_frame),
|
|
.close = ff_ac3_encode_close,
|
|
.p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
|
|
AV_SAMPLE_FMT_NONE },
|
|
.p.priv_class = &ff_ac3enc_class,
|
|
.p.supported_samplerates = ff_ac3_sample_rate_tab,
|
|
.p.ch_layouts = ff_ac3_ch_layouts,
|
|
.defaults = ff_ac3_enc_defaults,
|
|
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
|
|
};
|