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ffmpeg/libavcodec/mpegaudiodec_float.c
Andreas Rheinhardt ed33bbe678 avcodec/mpegaudiodec: Hardcode tables to save space 
The csa_tables (which always consist of 32 entries of four byte each,
but the type depends upon whether the decoder is fixed or
floating-point) are currently initialized once during decoder
initialization; yet it turns out that this is actually no benefit: The
code used to initialize these tables takes up 153 (fixed point) and 122
(floating point) bytes when compiled with GCC 9.3 with -O3 on x64, so it
is better to just hardcode these tables.

Essentially the same applies to the is_tables: They have a size of 128B
each and the code to initialize them occupies 149 (fixed point) resp.
140 (floating point) bytes. So hardcode them, too.

To make the origin of the tables clear, references to the code used to
create them have been added.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-12-08 17:51:47 +01:00

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/*
* Float MPEG Audio decoder
* Copyright (c) 2010 Michael Niedermayer
*
* 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
*/
#include "config.h"
#include "libavutil/samplefmt.h"
#define USE_FLOATS 1
#include "mpegaudio.h"
#define SHR(a,b) ((a)*(1.0f/(1<<(b))))
#define FIXR_OLD(a) ((int)((a) * FRAC_ONE + 0.5))
#define FIXR(x) ((float)(x))
#define FIXHR(x) ((float)(x))
#define MULH3(x, y, s) ((s)*(y)*(x))
#define MULLx(x, y, s) ((y)*(x))
#define RENAME(a) a ## _float
#define OUT_FMT AV_SAMPLE_FMT_FLT
#define OUT_FMT_P AV_SAMPLE_FMT_FLTP
/* Intensity stereo table. See commit b91d46614df189e7905538e7f5c4ed9c7ed0d274
* (float based mp1/mp2/mp3 decoders.) for how they were created. */
static const float is_table[2][16] = {
{ 0.000000000000000000e+00, 2.113248705863952637e-01, 3.660253882408142090e-01,
5.000000000000000000e-01, 6.339746117591857910e-01, 7.886751294136047363e-01,
1.000000000000000000e+00 },
{ 1.000000000000000000e+00, 7.886751294136047363e-01, 6.339746117591857910e-01,
5.000000000000000000e-01, 3.660253882408142090e-01, 2.113248705863952637e-01,
0.000000000000000000e+00 }
};
/* Antialiasing table. See commit 6f1ec38ce2193d3d4cacd87edb452c6d7ba751ec
* (mpegaudio: clean up compute_antialias() definition) for how they were
* created. */
static const float csa_table[8][4] = {
{ 8.574929237365722656e-01, -5.144957900047302246e-01,
3.429971337318420410e-01, -1.371988654136657715e+00 },
{ 8.817420005798339844e-01, -4.717319905757904053e-01,
4.100100100040435791e-01, -1.353474020957946777e+00 },
{ 9.496286511421203613e-01, -3.133774697780609131e-01,
6.362511515617370605e-01, -1.263006091117858887e+00 },
{ 9.833145737648010254e-01, -1.819131970405578613e-01,
8.014013767242431641e-01, -1.165227770805358887e+00 },
{ 9.955177903175354004e-01, -9.457419067621231079e-02,
9.009436368942260742e-01, -1.090092062950134277e+00 },
{ 9.991605877876281738e-01, -4.096558317542076111e-02,
9.581949710845947266e-01, -1.040126085281372070e+00 },
{ 9.998992085456848145e-01, -1.419856864959001541e-02,
9.857006072998046875e-01, -1.014097809791564941e+00 },
{ 9.999931454658508301e-01, -3.699974622577428818e-03,
9.962931871414184570e-01, -1.003693103790283203e+00 }
};
#include "mpegaudiodec_template.c"
#if CONFIG_MP1FLOAT_DECODER
AVCodec ff_mp1float_decoder = {
.name = "mp1float",
.long_name = NULL_IF_CONFIG_SMALL("MP1 (MPEG audio layer 1)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MP1,
.priv_data_size = sizeof(MPADecodeContext),
.init = decode_init,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.flush = flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_FLT,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif
#if CONFIG_MP2FLOAT_DECODER
AVCodec ff_mp2float_decoder = {
.name = "mp2float",
.long_name = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MP2,
.priv_data_size = sizeof(MPADecodeContext),
.init = decode_init,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.flush = flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_FLT,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif
#if CONFIG_MP3FLOAT_DECODER
AVCodec ff_mp3float_decoder = {
.name = "mp3float",
.long_name = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MP3,
.priv_data_size = sizeof(MPADecodeContext),
.init = decode_init,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.flush = flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_FLT,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif
#if CONFIG_MP3ADUFLOAT_DECODER
AVCodec ff_mp3adufloat_decoder = {
.name = "mp3adufloat",
.long_name = NULL_IF_CONFIG_SMALL("ADU (Application Data Unit) MP3 (MPEG audio layer 3)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MP3ADU,
.priv_data_size = sizeof(MPADecodeContext),
.init = decode_init,
.decode = decode_frame_adu,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.flush = flush,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_FLT,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
#endif
#if CONFIG_MP3ON4FLOAT_DECODER
AVCodec ff_mp3on4float_decoder = {
.name = "mp3on4float",
.long_name = NULL_IF_CONFIG_SMALL("MP3onMP4"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MP3ON4,
.priv_data_size = sizeof(MP3On4DecodeContext),
.init = decode_init_mp3on4,
.close = decode_close_mp3on4,
.decode = decode_frame_mp3on4,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.flush = flush_mp3on4,
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
#endif
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