0,0 → 1,169 |
/* |
* 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 = { |
.class_name = "Fixed-Point AC-3 Encoder", |
.item_name = av_default_item_name, |
.option = ac3_options, |
.version = 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(void *dsp, int16_t *output, const int16_t *input, |
const int16_t *window, unsigned int len) |
{ |
DSPContext *dsp0 = dsp; |
dsp0->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", |
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"), |
.type = AVMEDIA_TYPE_AUDIO, |
.id = AV_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_S16P, |
AV_SAMPLE_FMT_NONE }, |
.priv_class = &ac3enc_class, |
.channel_layouts = ff_ac3_channel_layouts, |
.defaults = ac3_defaults, |
}; |