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Channel coupling is an optional AC-3 feature that increases quality by combining high frequency information from multiple channels into a single channel. The per-channel high frequency information is sent with less accuracy in both the frequency and time domains. This allows more bits to be used for lower frequencies while preserving enough information to reconstruct the high frequencies.
315 lines
9.8 KiB
C
315 lines
9.8 KiB
C
/*
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* AC-3 tables
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* copyright (c) 2001 Fabrice Bellard
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* tables taken directly from the AC-3 spec.
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*/
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#include "libavutil/audioconvert.h"
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#include "avcodec.h"
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#include "ac3tab.h"
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/**
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* Possible frame sizes.
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* from ATSC A/52 Table 5.18 Frame Size Code Table.
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*/
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const uint16_t ff_ac3_frame_size_tab[38][3] = {
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{ 64, 69, 96 },
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{ 64, 70, 96 },
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{ 80, 87, 120 },
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{ 80, 88, 120 },
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{ 96, 104, 144 },
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{ 96, 105, 144 },
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{ 112, 121, 168 },
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{ 112, 122, 168 },
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{ 128, 139, 192 },
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{ 128, 140, 192 },
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{ 160, 174, 240 },
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{ 160, 175, 240 },
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{ 192, 208, 288 },
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{ 192, 209, 288 },
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{ 224, 243, 336 },
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{ 224, 244, 336 },
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{ 256, 278, 384 },
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{ 256, 279, 384 },
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{ 320, 348, 480 },
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{ 320, 349, 480 },
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{ 384, 417, 576 },
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{ 384, 418, 576 },
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{ 448, 487, 672 },
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{ 448, 488, 672 },
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{ 512, 557, 768 },
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{ 512, 558, 768 },
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{ 640, 696, 960 },
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{ 640, 697, 960 },
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{ 768, 835, 1152 },
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{ 768, 836, 1152 },
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{ 896, 975, 1344 },
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{ 896, 976, 1344 },
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{ 1024, 1114, 1536 },
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{ 1024, 1115, 1536 },
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{ 1152, 1253, 1728 },
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{ 1152, 1254, 1728 },
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{ 1280, 1393, 1920 },
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{ 1280, 1394, 1920 },
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};
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/**
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* Map audio coding mode (acmod) to number of full-bandwidth channels.
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* from ATSC A/52 Table 5.8 Audio Coding Mode
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*/
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const uint8_t ff_ac3_channels_tab[8] = {
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2, 1, 2, 3, 3, 4, 4, 5
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};
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/**
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* Map audio coding mode (acmod) to channel layout mask.
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*/
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const uint16_t ff_ac3_channel_layout_tab[8] = {
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AV_CH_LAYOUT_STEREO,
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AV_CH_LAYOUT_MONO,
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AV_CH_LAYOUT_STEREO,
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AV_CH_LAYOUT_SURROUND,
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AV_CH_LAYOUT_2_1,
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AV_CH_LAYOUT_4POINT0,
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AV_CH_LAYOUT_2_2,
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AV_CH_LAYOUT_5POINT0
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};
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#define COMMON_CHANNEL_MAP \
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{ { 0, 1, }, { 0, 1, 2, } },\
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{ { 0, }, { 0, 1, } },\
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{ { 0, 1, }, { 0, 1, 2, } },\
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{ { 0, 2, 1, }, { 0, 2, 1, 3, } },\
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{ { 0, 1, 2, }, { 0, 1, 3, 2, } },\
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{ { 0, 2, 1, 3, }, { 0, 2, 1, 4, 3, } },
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/**
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* Table to remap channels from SMPTE order to AC-3 order.
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* [channel_mode][lfe][ch]
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*/
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const uint8_t ff_ac3_enc_channel_map[8][2][6] = {
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COMMON_CHANNEL_MAP
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{ { 0, 1, 2, 3, }, { 0, 1, 3, 4, 2, } },
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{ { 0, 2, 1, 3, 4, }, { 0, 2, 1, 4, 5, 3 } },
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};
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/**
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* Table to remap channels from from AC-3 order to SMPTE order.
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* [channel_mode][lfe][ch]
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*/
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const uint8_t ff_ac3_dec_channel_map[8][2][6] = {
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COMMON_CHANNEL_MAP
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{ { 0, 1, 2, 3, }, { 0, 1, 4, 2, 3, } },
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{ { 0, 2, 1, 3, 4, }, { 0, 2, 1, 5, 3, 4 } },
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};
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/* possible frequencies */
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const uint16_t ff_ac3_sample_rate_tab[3] = { 48000, 44100, 32000 };
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/* possible bitrates */
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const uint16_t ff_ac3_bitrate_tab[19] = {
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32, 40, 48, 56, 64, 80, 96, 112, 128,
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160, 192, 224, 256, 320, 384, 448, 512, 576, 640
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};
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/**
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* Table of bin locations for rematrixing bands
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* reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
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*/
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const uint8_t ff_ac3_rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
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/**
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* Table E2.16 Default Coupling Banding Structure
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*/
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const uint8_t ff_eac3_default_cpl_band_struct[18] = {
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0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1
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};
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/* AC-3 MDCT window */
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/* MDCT window */
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DECLARE_ALIGNED(16, const int16_t, ff_ac3_window)[AC3_WINDOW_SIZE/2] = {
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4, 7, 12, 16, 21, 28, 34, 42,
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51, 61, 72, 84, 97, 111, 127, 145,
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164, 184, 207, 231, 257, 285, 315, 347,
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382, 419, 458, 500, 544, 591, 641, 694,
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750, 810, 872, 937, 1007, 1079, 1155, 1235,
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1318, 1406, 1497, 1593, 1692, 1796, 1903, 2016,
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2132, 2253, 2379, 2509, 2644, 2783, 2927, 3076,
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3230, 3389, 3552, 3721, 3894, 4072, 4255, 4444,
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4637, 4835, 5038, 5246, 5459, 5677, 5899, 6127,
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6359, 6596, 6837, 7083, 7334, 7589, 7848, 8112,
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8380, 8652, 8927, 9207, 9491, 9778,10069,10363,
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10660,10960,11264,11570,11879,12190,12504,12820,
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13138,13458,13780,14103,14427,14753,15079,15407,
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15735,16063,16392,16720,17049,17377,17705,18032,
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18358,18683,19007,19330,19651,19970,20287,20602,
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20914,21225,21532,21837,22139,22438,22733,23025,
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23314,23599,23880,24157,24430,24699,24964,25225,
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25481,25732,25979,26221,26459,26691,26919,27142,
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27359,27572,27780,27983,28180,28373,28560,28742,
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28919,29091,29258,29420,29577,29729,29876,30018,
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30155,30288,30415,30538,30657,30771,30880,30985,
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31086,31182,31274,31363,31447,31528,31605,31678,
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31747,31814,31877,31936,31993,32046,32097,32145,
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32190,32232,32272,32310,32345,32378,32409,32438,
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32465,32490,32513,32535,32556,32574,32592,32608,
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32623,32636,32649,32661,32671,32681,32690,32698,
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32705,32712,32718,32724,32729,32733,32737,32741,
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32744,32747,32750,32752,32754,32756,32757,32759,
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32760,32761,32762,32763,32764,32764,32765,32765,
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32766,32766,32766,32766,32767,32767,32767,32767,
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32767,32767,32767,32767,32767,32767,32767,32767,
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32767,32767,32767,32767,32767,32767,32767,32767,
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};
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const uint8_t ff_ac3_log_add_tab[260]= {
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0x40,0x3f,0x3e,0x3d,0x3c,0x3b,0x3a,0x39,0x38,0x37,
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0x36,0x35,0x34,0x34,0x33,0x32,0x31,0x30,0x2f,0x2f,
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0x2e,0x2d,0x2c,0x2c,0x2b,0x2a,0x29,0x29,0x28,0x27,
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0x26,0x26,0x25,0x24,0x24,0x23,0x23,0x22,0x21,0x21,
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0x20,0x20,0x1f,0x1e,0x1e,0x1d,0x1d,0x1c,0x1c,0x1b,
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0x1b,0x1a,0x1a,0x19,0x19,0x18,0x18,0x17,0x17,0x16,
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0x16,0x15,0x15,0x15,0x14,0x14,0x13,0x13,0x13,0x12,
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0x12,0x12,0x11,0x11,0x11,0x10,0x10,0x10,0x0f,0x0f,
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0x0f,0x0e,0x0e,0x0e,0x0d,0x0d,0x0d,0x0d,0x0c,0x0c,
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0x0c,0x0c,0x0b,0x0b,0x0b,0x0b,0x0a,0x0a,0x0a,0x0a,
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0x0a,0x09,0x09,0x09,0x09,0x09,0x08,0x08,0x08,0x08,
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0x08,0x08,0x07,0x07,0x07,0x07,0x07,0x07,0x06,0x06,
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0x06,0x06,0x06,0x06,0x06,0x06,0x05,0x05,0x05,0x05,
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0x05,0x05,0x05,0x05,0x04,0x04,0x04,0x04,0x04,0x04,
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0x04,0x04,0x04,0x04,0x04,0x03,0x03,0x03,0x03,0x03,
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0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x02,
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0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,
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0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x02,0x01,0x01,
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0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,
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0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,
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0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,
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0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
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};
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const uint16_t ff_ac3_hearing_threshold_tab[AC3_CRITICAL_BANDS][3]= {
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{ 0x04d0,0x04f0,0x0580 },
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{ 0x04d0,0x04f0,0x0580 },
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{ 0x0440,0x0460,0x04b0 },
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{ 0x0400,0x0410,0x0450 },
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{ 0x03e0,0x03e0,0x0420 },
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{ 0x03c0,0x03d0,0x03f0 },
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{ 0x03b0,0x03c0,0x03e0 },
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{ 0x03b0,0x03b0,0x03d0 },
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{ 0x03a0,0x03b0,0x03c0 },
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{ 0x03a0,0x03a0,0x03b0 },
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{ 0x03a0,0x03a0,0x03b0 },
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{ 0x03a0,0x03a0,0x03b0 },
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{ 0x03a0,0x03a0,0x03a0 },
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{ 0x0390,0x03a0,0x03a0 },
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{ 0x0390,0x0390,0x03a0 },
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{ 0x0390,0x0390,0x03a0 },
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{ 0x0380,0x0390,0x03a0 },
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{ 0x0380,0x0380,0x03a0 },
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{ 0x0370,0x0380,0x03a0 },
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{ 0x0370,0x0380,0x03a0 },
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{ 0x0360,0x0370,0x0390 },
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{ 0x0360,0x0370,0x0390 },
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{ 0x0350,0x0360,0x0390 },
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{ 0x0350,0x0360,0x0390 },
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{ 0x0340,0x0350,0x0380 },
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{ 0x0340,0x0350,0x0380 },
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{ 0x0330,0x0340,0x0380 },
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{ 0x0320,0x0340,0x0370 },
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{ 0x0310,0x0320,0x0360 },
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{ 0x0300,0x0310,0x0350 },
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{ 0x02f0,0x0300,0x0340 },
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{ 0x02f0,0x02f0,0x0330 },
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{ 0x02f0,0x02f0,0x0320 },
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{ 0x02f0,0x02f0,0x0310 },
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{ 0x0300,0x02f0,0x0300 },
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{ 0x0310,0x0300,0x02f0 },
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{ 0x0340,0x0320,0x02f0 },
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{ 0x0390,0x0350,0x02f0 },
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{ 0x03e0,0x0390,0x0300 },
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{ 0x0420,0x03e0,0x0310 },
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{ 0x0460,0x0420,0x0330 },
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{ 0x0490,0x0450,0x0350 },
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{ 0x04a0,0x04a0,0x03c0 },
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{ 0x0460,0x0490,0x0410 },
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{ 0x0440,0x0460,0x0470 },
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{ 0x0440,0x0440,0x04a0 },
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{ 0x0520,0x0480,0x0460 },
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{ 0x0800,0x0630,0x0440 },
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{ 0x0840,0x0840,0x0450 },
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{ 0x0840,0x0840,0x04e0 },
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};
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const uint8_t ff_ac3_bap_tab[64]= {
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0, 1, 1, 1, 1, 1, 2, 2, 3, 3,
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3, 4, 4, 5, 5, 6, 6, 6, 6, 7,
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7, 7, 7, 8, 8, 8, 8, 9, 9, 9,
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9, 10, 10, 10, 10, 11, 11, 11, 11, 12,
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12, 12, 12, 13, 13, 13, 13, 14, 14, 14,
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14, 14, 14, 14, 14, 15, 15, 15, 15, 15,
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15, 15, 15, 15,
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};
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const uint8_t ff_ac3_slow_decay_tab[4]={
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0x0f, 0x11, 0x13, 0x15,
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};
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const uint8_t ff_ac3_fast_decay_tab[4]={
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0x3f, 0x53, 0x67, 0x7b,
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};
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const uint16_t ff_ac3_slow_gain_tab[4]= {
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0x540, 0x4d8, 0x478, 0x410,
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};
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const uint16_t ff_ac3_db_per_bit_tab[4]= {
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0x000, 0x700, 0x900, 0xb00,
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};
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const int16_t ff_ac3_floor_tab[8]= {
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0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800,
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};
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const uint16_t ff_ac3_fast_gain_tab[8]= {
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0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400,
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};
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/**
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* Default channel map for a dependent substream defined by acmod
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*/
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const uint16_t ff_eac3_default_chmap[8] = {
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AC3_CHMAP_L | AC3_CHMAP_R, // FIXME Ch1+Ch2
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AC3_CHMAP_C,
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AC3_CHMAP_L | AC3_CHMAP_R,
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AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R,
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AC3_CHMAP_L | AC3_CHMAP_R | AC3_CHMAP_C_SUR,
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AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R | AC3_CHMAP_C_SUR,
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AC3_CHMAP_L | AC3_CHMAP_R | AC3_CHMAP_L_SUR | AC3_CHMAP_R_SUR,
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AC3_CHMAP_L | AC3_CHMAP_C | AC3_CHMAP_R | AC3_CHMAP_L_SUR | AC3_CHMAP_R_SUR
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};
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