mirror of https://git.ffmpeg.org/ffmpeg.git
163 lines
4.6 KiB
C
163 lines
4.6 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
|
|
* fixed-point AC-3 encoder.
|
|
*/
|
|
|
|
#define CONFIG_FFT_FLOAT 0
|
|
#undef CONFIG_AC3ENC_FLOAT
|
|
#include "internal.h"
|
|
#include "ac3enc.h"
|
|
#include "eac3enc.h"
|
|
|
|
#define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED
|
|
#include "ac3enc_opts_template.c"
|
|
static const AVClass ac3enc_class = { "Fixed-Point AC-3 Encoder", av_default_item_name,
|
|
ac3fixed_options, LIBAVUTIL_VERSION_INT };
|
|
|
|
#include "ac3enc_template.c"
|
|
|
|
|
|
/**
|
|
* Finalize MDCT and free allocated memory.
|
|
*
|
|
* @param s AC-3 encoder private context
|
|
*/
|
|
av_cold void AC3_NAME(mdct_end)(AC3EncodeContext *s)
|
|
{
|
|
ff_mdct_end(&s->mdct);
|
|
}
|
|
|
|
|
|
/**
|
|
* Initialize MDCT tables.
|
|
*
|
|
* @param s AC-3 encoder private context
|
|
* @return 0 on success, negative error code on failure
|
|
*/
|
|
av_cold int AC3_NAME(mdct_init)(AC3EncodeContext *s)
|
|
{
|
|
int ret = ff_mdct_init(&s->mdct, 9, 0, -1.0);
|
|
s->mdct_window = ff_ac3_window;
|
|
return ret;
|
|
}
|
|
|
|
|
|
/*
|
|
* Apply KBD window to input samples prior to MDCT.
|
|
*/
|
|
static void apply_window(DSPContext *dsp, int16_t *output, const int16_t *input,
|
|
const int16_t *window, unsigned int len)
|
|
{
|
|
dsp->apply_window_int16(output, input, window, len);
|
|
}
|
|
|
|
|
|
/*
|
|
* Normalize the input samples to use the maximum available precision.
|
|
* This assumes signed 16-bit input samples.
|
|
*/
|
|
static int normalize_samples(AC3EncodeContext *s)
|
|
{
|
|
int v = s->ac3dsp.ac3_max_msb_abs_int16(s->windowed_samples, AC3_WINDOW_SIZE);
|
|
v = 14 - av_log2(v);
|
|
if (v > 0)
|
|
s->ac3dsp.ac3_lshift_int16(s->windowed_samples, AC3_WINDOW_SIZE, v);
|
|
/* +6 to right-shift from 31-bit to 25-bit */
|
|
return v + 6;
|
|
}
|
|
|
|
|
|
/*
|
|
* Scale MDCT coefficients to 25-bit signed fixed-point.
|
|
*/
|
|
static void scale_coefficients(AC3EncodeContext *s)
|
|
{
|
|
int blk, ch;
|
|
|
|
for (blk = 0; blk < s->num_blocks; blk++) {
|
|
AC3Block *block = &s->blocks[blk];
|
|
for (ch = 1; ch <= s->channels; ch++) {
|
|
s->ac3dsp.ac3_rshift_int32(block->mdct_coef[ch], AC3_MAX_COEFS,
|
|
block->coeff_shift[ch]);
|
|
}
|
|
}
|
|
}
|
|
|
|
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(DSPContext *dsp, int32_t *coef, unsigned int len)
|
|
{
|
|
dsp->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);
|
|
}
|
|
}
|
|
|
|
|
|
static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
|
|
{
|
|
AC3EncodeContext *s = avctx->priv_data;
|
|
s->fixed_point = 1;
|
|
return ff_ac3_encode_init(avctx);
|
|
}
|
|
|
|
|
|
AVCodec ff_ac3_fixed_encoder = {
|
|
.name = "ac3_fixed",
|
|
.type = AVMEDIA_TYPE_AUDIO,
|
|
.id = CODEC_ID_AC3,
|
|
.priv_data_size = sizeof(AC3EncodeContext),
|
|
.init = ac3_fixed_encode_init,
|
|
.encode2 = ff_ac3_fixed_encode_frame,
|
|
.close = ff_ac3_encode_close,
|
|
.sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
|
|
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
|
|
.priv_class = &ac3enc_class,
|
|
.channel_layouts = ff_ac3_channel_layouts,
|
|
.defaults = ac3_defaults,
|
|
};
|