ffmpeg / libavcodec / ac3dec.c @ 80ba1ddb
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/*
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* AC-3 Audio Decoder
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* This code was developed as part of Google Summer of Code 2006.
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* E-AC-3 support was added as part of Google Summer of Code 2007.
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*
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* Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com)
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* Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
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* Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; 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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#include <stdio.h> |
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#include <stddef.h> |
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#include <math.h> |
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#include <string.h> |
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#include "libavutil/crc.h" |
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#include "internal.h" |
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#include "aac_ac3_parser.h" |
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#include "ac3_parser.h" |
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#include "ac3dec.h" |
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#include "ac3dec_data.h" |
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|
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/** Large enough for maximum possible frame size when the specification limit is ignored */
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#define AC3_FRAME_BUFFER_SIZE 32768 |
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|
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/**
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* table for ungrouping 3 values in 7 bits.
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* used for exponents and bap=2 mantissas
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*/
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static uint8_t ungroup_3_in_7_bits_tab[128][3]; |
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/** tables for ungrouping mantissas */
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static int b1_mantissas[32][3]; |
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static int b2_mantissas[128][3]; |
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static int b3_mantissas[8]; |
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static int b4_mantissas[128][2]; |
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static int b5_mantissas[16]; |
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|
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/**
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* Quantization table: levels for symmetric. bits for asymmetric.
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* reference: Table 7.18 Mapping of bap to Quantizer
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*/
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static const uint8_t quantization_tab[16] = { |
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0, 3, 5, 7, 11, 15, |
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5, 6, 7, 8, 9, 10, 11, 12, 14, 16 |
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}; |
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|
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/** dynamic range table. converts codes to scale factors. */
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static float dynamic_range_tab[256]; |
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|
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/** Adjustments in dB gain */
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#define LEVEL_PLUS_3DB 1.4142135623730950 |
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#define LEVEL_PLUS_1POINT5DB 1.1892071150027209 |
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#define LEVEL_MINUS_1POINT5DB 0.8408964152537145 |
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#define LEVEL_MINUS_3DB 0.7071067811865476 |
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#define LEVEL_MINUS_4POINT5DB 0.5946035575013605 |
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#define LEVEL_MINUS_6DB 0.5000000000000000 |
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#define LEVEL_MINUS_9DB 0.3535533905932738 |
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#define LEVEL_ZERO 0.0000000000000000 |
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#define LEVEL_ONE 1.0000000000000000 |
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|
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static const float gain_levels[9] = { |
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LEVEL_PLUS_3DB, |
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LEVEL_PLUS_1POINT5DB, |
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LEVEL_ONE, |
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LEVEL_MINUS_1POINT5DB, |
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LEVEL_MINUS_3DB, |
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LEVEL_MINUS_4POINT5DB, |
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LEVEL_MINUS_6DB, |
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LEVEL_ZERO, |
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LEVEL_MINUS_9DB |
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}; |
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|
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/**
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* Table for center mix levels
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* reference: Section 5.4.2.4 cmixlev
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*/
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static const uint8_t center_levels[4] = { 4, 5, 6, 5 }; |
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/**
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* Table for surround mix levels
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* reference: Section 5.4.2.5 surmixlev
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*/
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static const uint8_t surround_levels[4] = { 4, 6, 7, 6 }; |
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/**
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* Table for default stereo downmixing coefficients
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* reference: Section 7.8.2 Downmixing Into Two Channels
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*/
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static const uint8_t ac3_default_coeffs[8][5][2] = { |
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{ { 2, 7 }, { 7, 2 }, },
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{ { 4, 4 }, },
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{ { 2, 7 }, { 7, 2 }, },
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{ { 2, 7 }, { 5, 5 }, { 7, 2 }, },
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{ { 2, 7 }, { 7, 2 }, { 6, 6 }, },
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{ { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, },
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{ { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
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{ { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
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}; |
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/**
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* Symmetrical Dequantization
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* reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
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* Tables 7.19 to 7.23
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*/
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static inline int |
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symmetric_dequant(int code, int levels) |
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{
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return ((code - (levels >> 1)) << 24) / levels; |
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} |
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/*
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* Initialize tables at runtime.
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*/
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static av_cold void ac3_tables_init(void) |
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{
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int i;
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/* generate table for ungrouping 3 values in 7 bits
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reference: Section 7.1.3 Exponent Decoding */
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for(i=0; i<128; i++) { |
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ungroup_3_in_7_bits_tab[i][0] = i / 25; |
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ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5; |
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ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5; |
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} |
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/* generate grouped mantissa tables
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reference: Section 7.3.5 Ungrouping of Mantissas */
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for(i=0; i<32; i++) { |
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/* bap=1 mantissas */
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b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3); |
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b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3); |
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b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3); |
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} |
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for(i=0; i<128; i++) { |
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/* bap=2 mantissas */
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b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5); |
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b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5); |
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b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5); |
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/* bap=4 mantissas */
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b4_mantissas[i][0] = symmetric_dequant(i / 11, 11); |
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b4_mantissas[i][1] = symmetric_dequant(i % 11, 11); |
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} |
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/* generate ungrouped mantissa tables
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reference: Tables 7.21 and 7.23 */
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for(i=0; i<7; i++) { |
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/* bap=3 mantissas */
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b3_mantissas[i] = symmetric_dequant(i, 7);
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} |
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for(i=0; i<15; i++) { |
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/* bap=5 mantissas */
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b5_mantissas[i] = symmetric_dequant(i, 15);
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} |
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/* generate dynamic range table
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reference: Section 7.7.1 Dynamic Range Control */
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for(i=0; i<256; i++) { |
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int v = (i >> 5) - ((i >> 7) << 3) - 5; |
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dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20); |
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} |
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} |
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/**
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* AVCodec initialization
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*/
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static av_cold int ac3_decode_init(AVCodecContext *avctx) |
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{
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AC3DecodeContext *s = avctx->priv_data; |
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s->avctx = avctx; |
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ff_ac3_common_init(); |
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ac3_tables_init(); |
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ff_mdct_init(&s->imdct_256, 8, 1, 1.0); |
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ff_mdct_init(&s->imdct_512, 9, 1, 1.0); |
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ff_kbd_window_init(s->window, 5.0, 256); |
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dsputil_init(&s->dsp, avctx); |
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av_lfg_init(&s->dith_state, 0);
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/* set scale value for float to int16 conversion */
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s->mul_bias = 32767.0f; |
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/* allow downmixing to stereo or mono */
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if (avctx->channels > 0 && avctx->request_channels > 0 && |
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avctx->request_channels < avctx->channels && |
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avctx->request_channels <= 2) {
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avctx->channels = avctx->request_channels; |
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} |
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s->downmixed = 1;
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/* allocate context input buffer */
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if (avctx->error_recognition >= FF_ER_CAREFUL) {
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s->input_buffer = av_mallocz(AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE); |
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if (!s->input_buffer)
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return AVERROR(ENOMEM);
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} |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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return 0; |
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} |
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/**
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* Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
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* GetBitContext within AC3DecodeContext must point to
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* the start of the synchronized AC-3 bitstream.
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*/
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static int ac3_parse_header(AC3DecodeContext *s) |
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{
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GetBitContext *gbc = &s->gbc; |
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int i;
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/* read the rest of the bsi. read twice for dual mono mode. */
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i = !(s->channel_mode); |
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do {
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skip_bits(gbc, 5); // skip dialog normalization |
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if (get_bits1(gbc))
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skip_bits(gbc, 8); //skip compression |
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if (get_bits1(gbc))
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skip_bits(gbc, 8); //skip language code |
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if (get_bits1(gbc))
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skip_bits(gbc, 7); //skip audio production information |
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} while (i--);
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skip_bits(gbc, 2); //skip copyright bit and original bitstream bit |
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/* skip the timecodes (or extra bitstream information for Alternate Syntax)
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TODO: read & use the xbsi1 downmix levels */
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if (get_bits1(gbc))
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skip_bits(gbc, 14); //skip timecode1 / xbsi1 |
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if (get_bits1(gbc))
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skip_bits(gbc, 14); //skip timecode2 / xbsi2 |
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/* skip additional bitstream info */
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if (get_bits1(gbc)) {
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i = get_bits(gbc, 6);
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do {
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skip_bits(gbc, 8);
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} while(i--);
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} |
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return 0; |
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} |
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/**
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* Common function to parse AC-3 or E-AC-3 frame header
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*/
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static int parse_frame_header(AC3DecodeContext *s) |
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{
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AC3HeaderInfo hdr; |
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int err;
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err = ff_ac3_parse_header(&s->gbc, &hdr); |
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if(err)
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return err;
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/* get decoding parameters from header info */
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s->bit_alloc_params.sr_code = hdr.sr_code; |
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s->channel_mode = hdr.channel_mode; |
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s->channel_layout = hdr.channel_layout; |
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s->lfe_on = hdr.lfe_on; |
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s->bit_alloc_params.sr_shift = hdr.sr_shift; |
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s->sample_rate = hdr.sample_rate; |
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s->bit_rate = hdr.bit_rate; |
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s->channels = hdr.channels; |
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s->fbw_channels = s->channels - s->lfe_on; |
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s->lfe_ch = s->fbw_channels + 1;
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s->frame_size = hdr.frame_size; |
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s->center_mix_level = hdr.center_mix_level; |
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s->surround_mix_level = hdr.surround_mix_level; |
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s->num_blocks = hdr.num_blocks; |
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s->frame_type = hdr.frame_type; |
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s->substreamid = hdr.substreamid; |
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if(s->lfe_on) {
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s->start_freq[s->lfe_ch] = 0;
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s->end_freq[s->lfe_ch] = 7;
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s->num_exp_groups[s->lfe_ch] = 2;
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s->channel_in_cpl[s->lfe_ch] = 0;
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} |
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if (hdr.bitstream_id <= 10) { |
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s->eac3 = 0;
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s->snr_offset_strategy = 2;
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s->block_switch_syntax = 1;
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s->dither_flag_syntax = 1;
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s->bit_allocation_syntax = 1;
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s->fast_gain_syntax = 0;
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s->first_cpl_leak = 0;
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s->dba_syntax = 1;
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s->skip_syntax = 1;
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memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht)); |
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return ac3_parse_header(s);
|
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} else if (CONFIG_EAC3_DECODER) { |
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s->eac3 = 1;
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return ff_eac3_parse_header(s);
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} else {
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av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n");
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return -1; |
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} |
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} |
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/**
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* Set stereo downmixing coefficients based on frame header info.
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* reference: Section 7.8.2 Downmixing Into Two Channels
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*/
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static void set_downmix_coeffs(AC3DecodeContext *s) |
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{
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int i;
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float cmix = gain_levels[center_levels[s->center_mix_level]];
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float smix = gain_levels[surround_levels[s->surround_mix_level]];
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float norm0, norm1;
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for(i=0; i<s->fbw_channels; i++) { |
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s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]]; |
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s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]]; |
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} |
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if(s->channel_mode > 1 && s->channel_mode & 1) { |
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s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix; |
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} |
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if(s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
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int nf = s->channel_mode - 2; |
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s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB; |
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} |
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if(s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
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int nf = s->channel_mode - 4; |
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s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix; |
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} |
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|
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/* renormalize */
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norm0 = norm1 = 0.0; |
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for(i=0; i<s->fbw_channels; i++) { |
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norm0 += s->downmix_coeffs[i][0];
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norm1 += s->downmix_coeffs[i][1];
|
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} |
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norm0 = 1.0f / norm0; |
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norm1 = 1.0f / norm1; |
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for(i=0; i<s->fbw_channels; i++) { |
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s->downmix_coeffs[i][0] *= norm0;
|
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s->downmix_coeffs[i][1] *= norm1;
|
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} |
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|
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if(s->output_mode == AC3_CHMODE_MONO) {
|
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for(i=0; i<s->fbw_channels; i++) |
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s->downmix_coeffs[i][0] = (s->downmix_coeffs[i][0] + s->downmix_coeffs[i][1]) * LEVEL_MINUS_3DB; |
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} |
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} |
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|
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/**
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* Decode the grouped exponents according to exponent strategy.
|
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* reference: Section 7.1.3 Exponent Decoding
|
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*/
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static int decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps, |
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uint8_t absexp, int8_t *dexps) |
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{
|
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int i, j, grp, group_size;
|
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int dexp[256]; |
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int expacc, prevexp;
|
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|
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/* unpack groups */
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group_size = exp_strategy + (exp_strategy == EXP_D45); |
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for(grp=0,i=0; grp<ngrps; grp++) { |
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expacc = get_bits(gbc, 7);
|
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dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
|
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dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
|
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dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
|
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} |
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|
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/* convert to absolute exps and expand groups */
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prevexp = absexp; |
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for(i=0,j=0; i<ngrps*3; i++) { |
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prevexp += dexp[i] - 2;
|
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if (prevexp > 24U) |
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return -1; |
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switch (group_size) {
|
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case 4: dexps[j++] = prevexp; |
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dexps[j++] = prevexp; |
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case 2: dexps[j++] = prevexp; |
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case 1: dexps[j++] = prevexp; |
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} |
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} |
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return 0; |
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} |
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|
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/**
|
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* Generate transform coefficients for each coupled channel in the coupling
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* range using the coupling coefficients and coupling coordinates.
|
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* reference: Section 7.4.3 Coupling Coordinate Format
|
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*/
|
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static void calc_transform_coeffs_cpl(AC3DecodeContext *s) |
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{
|
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int bin, band, ch;
|
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|
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bin = s->start_freq[CPL_CH]; |
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for (band = 0; band < s->num_cpl_bands; band++) { |
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int band_start = bin;
|
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int band_end = bin + s->cpl_band_sizes[band];
|
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for (ch = 1; ch <= s->fbw_channels; ch++) { |
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if (s->channel_in_cpl[ch]) {
|
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int cpl_coord = s->cpl_coords[ch][band] << 5; |
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for (bin = band_start; bin < band_end; bin++) {
|
| 419 |
s->fixed_coeffs[ch][bin] = MULH(s->fixed_coeffs[CPL_CH][bin] << 4, cpl_coord);
|
| 420 |
} |
| 421 |
if (ch == 2 && s->phase_flags[band]) { |
| 422 |
for (bin = band_start; bin < band_end; bin++)
|
| 423 |
s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin]; |
| 424 |
} |
| 425 |
} |
| 426 |
} |
| 427 |
bin = band_end; |
| 428 |
} |
| 429 |
} |
| 430 |
|
| 431 |
/**
|
| 432 |
* Grouped mantissas for 3-level 5-level and 11-level quantization
|
| 433 |
*/
|
| 434 |
typedef struct { |
| 435 |
int b1_mant[2]; |
| 436 |
int b2_mant[2]; |
| 437 |
int b4_mant;
|
| 438 |
int b1;
|
| 439 |
int b2;
|
| 440 |
int b4;
|
| 441 |
} mant_groups; |
| 442 |
|
| 443 |
/**
|
| 444 |
* Decode the transform coefficients for a particular channel
|
| 445 |
* reference: Section 7.3 Quantization and Decoding of Mantissas
|
| 446 |
*/
|
| 447 |
static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m) |
| 448 |
{
|
| 449 |
int start_freq = s->start_freq[ch_index];
|
| 450 |
int end_freq = s->end_freq[ch_index];
|
| 451 |
uint8_t *baps = s->bap[ch_index]; |
| 452 |
int8_t *exps = s->dexps[ch_index]; |
| 453 |
int *coeffs = s->fixed_coeffs[ch_index];
|
| 454 |
int dither = (ch_index == CPL_CH) || s->dither_flag[ch_index];
|
| 455 |
GetBitContext *gbc = &s->gbc; |
| 456 |
int freq;
|
| 457 |
|
| 458 |
for(freq = start_freq; freq < end_freq; freq++){
|
| 459 |
int bap = baps[freq];
|
| 460 |
int mantissa;
|
| 461 |
switch(bap){
|
| 462 |
case 0: |
| 463 |
if (dither)
|
| 464 |
mantissa = (av_lfg_get(&s->dith_state) & 0x7FFFFF) - 0x400000; |
| 465 |
else
|
| 466 |
mantissa = 0;
|
| 467 |
break;
|
| 468 |
case 1: |
| 469 |
if(m->b1){
|
| 470 |
m->b1--; |
| 471 |
mantissa = m->b1_mant[m->b1]; |
| 472 |
} |
| 473 |
else{
|
| 474 |
int bits = get_bits(gbc, 5); |
| 475 |
mantissa = b1_mantissas[bits][0];
|
| 476 |
m->b1_mant[1] = b1_mantissas[bits][1]; |
| 477 |
m->b1_mant[0] = b1_mantissas[bits][2]; |
| 478 |
m->b1 = 2;
|
| 479 |
} |
| 480 |
break;
|
| 481 |
case 2: |
| 482 |
if(m->b2){
|
| 483 |
m->b2--; |
| 484 |
mantissa = m->b2_mant[m->b2]; |
| 485 |
} |
| 486 |
else{
|
| 487 |
int bits = get_bits(gbc, 7); |
| 488 |
mantissa = b2_mantissas[bits][0];
|
| 489 |
m->b2_mant[1] = b2_mantissas[bits][1]; |
| 490 |
m->b2_mant[0] = b2_mantissas[bits][2]; |
| 491 |
m->b2 = 2;
|
| 492 |
} |
| 493 |
break;
|
| 494 |
case 3: |
| 495 |
mantissa = b3_mantissas[get_bits(gbc, 3)];
|
| 496 |
break;
|
| 497 |
case 4: |
| 498 |
if(m->b4){
|
| 499 |
m->b4 = 0;
|
| 500 |
mantissa = m->b4_mant; |
| 501 |
} |
| 502 |
else{
|
| 503 |
int bits = get_bits(gbc, 7); |
| 504 |
mantissa = b4_mantissas[bits][0];
|
| 505 |
m->b4_mant = b4_mantissas[bits][1];
|
| 506 |
m->b4 = 1;
|
| 507 |
} |
| 508 |
break;
|
| 509 |
case 5: |
| 510 |
mantissa = b5_mantissas[get_bits(gbc, 4)];
|
| 511 |
break;
|
| 512 |
default: /* 6 to 15 */ |
| 513 |
mantissa = get_bits(gbc, quantization_tab[bap]); |
| 514 |
/* Shift mantissa and sign-extend it. */
|
| 515 |
mantissa = (mantissa << (32-quantization_tab[bap]))>>8; |
| 516 |
break;
|
| 517 |
} |
| 518 |
coeffs[freq] = mantissa >> exps[freq]; |
| 519 |
} |
| 520 |
} |
| 521 |
|
| 522 |
/**
|
| 523 |
* Remove random dithering from coupling range coefficients with zero-bit
|
| 524 |
* mantissas for coupled channels which do not use dithering.
|
| 525 |
* reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
|
| 526 |
*/
|
| 527 |
static void remove_dithering(AC3DecodeContext *s) { |
| 528 |
int ch, i;
|
| 529 |
|
| 530 |
for(ch=1; ch<=s->fbw_channels; ch++) { |
| 531 |
if(!s->dither_flag[ch] && s->channel_in_cpl[ch]) {
|
| 532 |
for(i = s->start_freq[CPL_CH]; i<s->end_freq[CPL_CH]; i++) {
|
| 533 |
if(!s->bap[CPL_CH][i])
|
| 534 |
s->fixed_coeffs[ch][i] = 0;
|
| 535 |
} |
| 536 |
} |
| 537 |
} |
| 538 |
} |
| 539 |
|
| 540 |
static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch, |
| 541 |
mant_groups *m) |
| 542 |
{
|
| 543 |
if (!s->channel_uses_aht[ch]) {
|
| 544 |
ac3_decode_transform_coeffs_ch(s, ch, m); |
| 545 |
} else {
|
| 546 |
/* if AHT is used, mantissas for all blocks are encoded in the first
|
| 547 |
block of the frame. */
|
| 548 |
int bin;
|
| 549 |
if (!blk && CONFIG_EAC3_DECODER)
|
| 550 |
ff_eac3_decode_transform_coeffs_aht_ch(s, ch); |
| 551 |
for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
|
| 552 |
s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin]; |
| 553 |
} |
| 554 |
} |
| 555 |
} |
| 556 |
|
| 557 |
/**
|
| 558 |
* Decode the transform coefficients.
|
| 559 |
*/
|
| 560 |
static void decode_transform_coeffs(AC3DecodeContext *s, int blk) |
| 561 |
{
|
| 562 |
int ch, end;
|
| 563 |
int got_cplchan = 0; |
| 564 |
mant_groups m; |
| 565 |
|
| 566 |
m.b1 = m.b2 = m.b4 = 0;
|
| 567 |
|
| 568 |
for (ch = 1; ch <= s->channels; ch++) { |
| 569 |
/* transform coefficients for full-bandwidth channel */
|
| 570 |
decode_transform_coeffs_ch(s, blk, ch, &m); |
| 571 |
/* tranform coefficients for coupling channel come right after the
|
| 572 |
coefficients for the first coupled channel*/
|
| 573 |
if (s->channel_in_cpl[ch]) {
|
| 574 |
if (!got_cplchan) {
|
| 575 |
decode_transform_coeffs_ch(s, blk, CPL_CH, &m); |
| 576 |
calc_transform_coeffs_cpl(s); |
| 577 |
got_cplchan = 1;
|
| 578 |
} |
| 579 |
end = s->end_freq[CPL_CH]; |
| 580 |
} else {
|
| 581 |
end = s->end_freq[ch]; |
| 582 |
} |
| 583 |
do
|
| 584 |
s->fixed_coeffs[ch][end] = 0;
|
| 585 |
while(++end < 256); |
| 586 |
} |
| 587 |
|
| 588 |
/* zero the dithered coefficients for appropriate channels */
|
| 589 |
remove_dithering(s); |
| 590 |
} |
| 591 |
|
| 592 |
/**
|
| 593 |
* Stereo rematrixing.
|
| 594 |
* reference: Section 7.5.4 Rematrixing : Decoding Technique
|
| 595 |
*/
|
| 596 |
static void do_rematrixing(AC3DecodeContext *s) |
| 597 |
{
|
| 598 |
int bnd, i;
|
| 599 |
int end, bndend;
|
| 600 |
|
| 601 |
end = FFMIN(s->end_freq[1], s->end_freq[2]); |
| 602 |
|
| 603 |
for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) { |
| 604 |
if(s->rematrixing_flags[bnd]) {
|
| 605 |
bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd+1]);
|
| 606 |
for(i=ff_ac3_rematrix_band_tab[bnd]; i<bndend; i++) {
|
| 607 |
int tmp0 = s->fixed_coeffs[1][i]; |
| 608 |
s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i]; |
| 609 |
s->fixed_coeffs[2][i] = tmp0 - s->fixed_coeffs[2][i]; |
| 610 |
} |
| 611 |
} |
| 612 |
} |
| 613 |
} |
| 614 |
|
| 615 |
/**
|
| 616 |
* Inverse MDCT Transform.
|
| 617 |
* Convert frequency domain coefficients to time-domain audio samples.
|
| 618 |
* reference: Section 7.9.4 Transformation Equations
|
| 619 |
*/
|
| 620 |
static inline void do_imdct(AC3DecodeContext *s, int channels) |
| 621 |
{
|
| 622 |
int ch;
|
| 623 |
|
| 624 |
for (ch=1; ch<=channels; ch++) { |
| 625 |
if (s->block_switch[ch]) {
|
| 626 |
int i;
|
| 627 |
float *x = s->tmp_output+128; |
| 628 |
for(i=0; i<128; i++) |
| 629 |
x[i] = s->transform_coeffs[ch][2*i];
|
| 630 |
ff_imdct_half(&s->imdct_256, s->tmp_output, x); |
| 631 |
s->dsp.vector_fmul_window(s->output[ch-1], s->delay[ch-1], s->tmp_output, s->window, 128); |
| 632 |
for(i=0; i<128; i++) |
| 633 |
x[i] = s->transform_coeffs[ch][2*i+1]; |
| 634 |
ff_imdct_half(&s->imdct_256, s->delay[ch-1], x);
|
| 635 |
} else {
|
| 636 |
ff_imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]); |
| 637 |
s->dsp.vector_fmul_window(s->output[ch-1], s->delay[ch-1], s->tmp_output, s->window, 128); |
| 638 |
memcpy(s->delay[ch-1], s->tmp_output+128, 128*sizeof(float)); |
| 639 |
} |
| 640 |
} |
| 641 |
} |
| 642 |
|
| 643 |
/**
|
| 644 |
* Downmix the output to mono or stereo.
|
| 645 |
*/
|
| 646 |
void ff_ac3_downmix_c(float (*samples)[256], float (*matrix)[2], int out_ch, int in_ch, int len) |
| 647 |
{
|
| 648 |
int i, j;
|
| 649 |
float v0, v1;
|
| 650 |
if(out_ch == 2) { |
| 651 |
for(i=0; i<len; i++) { |
| 652 |
v0 = v1 = 0.0f; |
| 653 |
for(j=0; j<in_ch; j++) { |
| 654 |
v0 += samples[j][i] * matrix[j][0];
|
| 655 |
v1 += samples[j][i] * matrix[j][1];
|
| 656 |
} |
| 657 |
samples[0][i] = v0;
|
| 658 |
samples[1][i] = v1;
|
| 659 |
} |
| 660 |
} else if(out_ch == 1) { |
| 661 |
for(i=0; i<len; i++) { |
| 662 |
v0 = 0.0f; |
| 663 |
for(j=0; j<in_ch; j++) |
| 664 |
v0 += samples[j][i] * matrix[j][0];
|
| 665 |
samples[0][i] = v0;
|
| 666 |
} |
| 667 |
} |
| 668 |
} |
| 669 |
|
| 670 |
/**
|
| 671 |
* Upmix delay samples from stereo to original channel layout.
|
| 672 |
*/
|
| 673 |
static void ac3_upmix_delay(AC3DecodeContext *s) |
| 674 |
{
|
| 675 |
int channel_data_size = sizeof(s->delay[0]); |
| 676 |
switch(s->channel_mode) {
|
| 677 |
case AC3_CHMODE_DUALMONO:
|
| 678 |
case AC3_CHMODE_STEREO:
|
| 679 |
/* upmix mono to stereo */
|
| 680 |
memcpy(s->delay[1], s->delay[0], channel_data_size); |
| 681 |
break;
|
| 682 |
case AC3_CHMODE_2F2R:
|
| 683 |
memset(s->delay[3], 0, channel_data_size); |
| 684 |
case AC3_CHMODE_2F1R:
|
| 685 |
memset(s->delay[2], 0, channel_data_size); |
| 686 |
break;
|
| 687 |
case AC3_CHMODE_3F2R:
|
| 688 |
memset(s->delay[4], 0, channel_data_size); |
| 689 |
case AC3_CHMODE_3F1R:
|
| 690 |
memset(s->delay[3], 0, channel_data_size); |
| 691 |
case AC3_CHMODE_3F:
|
| 692 |
memcpy(s->delay[2], s->delay[1], channel_data_size); |
| 693 |
memset(s->delay[1], 0, channel_data_size); |
| 694 |
break;
|
| 695 |
} |
| 696 |
} |
| 697 |
|
| 698 |
/**
|
| 699 |
* Decode band structure for coupling, spectral extension, or enhanced coupling.
|
| 700 |
* The band structure defines how many subbands are in each band. For each
|
| 701 |
* subband in the range, 1 means it is combined with the previous band, and 0
|
| 702 |
* means that it starts a new band.
|
| 703 |
*
|
| 704 |
* @param[in] gbc bit reader context
|
| 705 |
* @param[in] blk block number
|
| 706 |
* @param[in] eac3 flag to indicate E-AC-3
|
| 707 |
* @param[in] ecpl flag to indicate enhanced coupling
|
| 708 |
* @param[in] start_subband subband number for start of range
|
| 709 |
* @param[in] end_subband subband number for end of range
|
| 710 |
* @param[in] default_band_struct default band structure table
|
| 711 |
* @param[out] num_bands number of bands (optionally NULL)
|
| 712 |
* @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
|
| 713 |
*/
|
| 714 |
static void decode_band_structure(GetBitContext *gbc, int blk, int eac3, |
| 715 |
int ecpl, int start_subband, int end_subband, |
| 716 |
const uint8_t *default_band_struct,
|
| 717 |
int *num_bands, uint8_t *band_sizes)
|
| 718 |
{
|
| 719 |
int subbnd, bnd, n_subbands, n_bands=0; |
| 720 |
uint8_t bnd_sz[22];
|
| 721 |
uint8_t coded_band_struct[22];
|
| 722 |
const uint8_t *band_struct;
|
| 723 |
|
| 724 |
n_subbands = end_subband - start_subband; |
| 725 |
|
| 726 |
/* decode band structure from bitstream or use default */
|
| 727 |
if (!eac3 || get_bits1(gbc)) {
|
| 728 |
for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) { |
| 729 |
coded_band_struct[subbnd] = get_bits1(gbc); |
| 730 |
} |
| 731 |
band_struct = coded_band_struct; |
| 732 |
} else if (!blk) { |
| 733 |
band_struct = &default_band_struct[start_subband+1];
|
| 734 |
} else {
|
| 735 |
/* no change in band structure */
|
| 736 |
return;
|
| 737 |
} |
| 738 |
|
| 739 |
/* calculate number of bands and band sizes based on band structure.
|
| 740 |
note that the first 4 subbands in enhanced coupling span only 6 bins
|
| 741 |
instead of 12. */
|
| 742 |
if (num_bands || band_sizes ) {
|
| 743 |
n_bands = n_subbands; |
| 744 |
bnd_sz[0] = ecpl ? 6 : 12; |
| 745 |
for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) { |
| 746 |
int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12; |
| 747 |
if (band_struct[subbnd-1]) { |
| 748 |
n_bands--; |
| 749 |
bnd_sz[bnd] += subbnd_size; |
| 750 |
} else {
|
| 751 |
bnd_sz[++bnd] = subbnd_size; |
| 752 |
} |
| 753 |
} |
| 754 |
} |
| 755 |
|
| 756 |
/* set optional output params */
|
| 757 |
if (num_bands)
|
| 758 |
*num_bands = n_bands; |
| 759 |
if (band_sizes)
|
| 760 |
memcpy(band_sizes, bnd_sz, n_bands); |
| 761 |
} |
| 762 |
|
| 763 |
/**
|
| 764 |
* Decode a single audio block from the AC-3 bitstream.
|
| 765 |
*/
|
| 766 |
static int decode_audio_block(AC3DecodeContext *s, int blk) |
| 767 |
{
|
| 768 |
int fbw_channels = s->fbw_channels;
|
| 769 |
int channel_mode = s->channel_mode;
|
| 770 |
int i, bnd, seg, ch;
|
| 771 |
int different_transforms;
|
| 772 |
int downmix_output;
|
| 773 |
int cpl_in_use;
|
| 774 |
GetBitContext *gbc = &s->gbc; |
| 775 |
uint8_t bit_alloc_stages[AC3_MAX_CHANNELS]; |
| 776 |
|
| 777 |
memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
|
| 778 |
|
| 779 |
/* block switch flags */
|
| 780 |
different_transforms = 0;
|
| 781 |
if (s->block_switch_syntax) {
|
| 782 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 783 |
s->block_switch[ch] = get_bits1(gbc); |
| 784 |
if(ch > 1 && s->block_switch[ch] != s->block_switch[1]) |
| 785 |
different_transforms = 1;
|
| 786 |
} |
| 787 |
} |
| 788 |
|
| 789 |
/* dithering flags */
|
| 790 |
if (s->dither_flag_syntax) {
|
| 791 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 792 |
s->dither_flag[ch] = get_bits1(gbc); |
| 793 |
} |
| 794 |
} |
| 795 |
|
| 796 |
/* dynamic range */
|
| 797 |
i = !(s->channel_mode); |
| 798 |
do {
|
| 799 |
if(get_bits1(gbc)) {
|
| 800 |
s->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) * |
| 801 |
s->avctx->drc_scale)+1.0; |
| 802 |
} else if(blk == 0) { |
| 803 |
s->dynamic_range[i] = 1.0f; |
| 804 |
} |
| 805 |
} while(i--);
|
| 806 |
|
| 807 |
/* spectral extension strategy */
|
| 808 |
if (s->eac3 && (!blk || get_bits1(gbc))) {
|
| 809 |
s->spx_in_use = get_bits1(gbc); |
| 810 |
if (s->spx_in_use) {
|
| 811 |
int dst_start_freq, dst_end_freq, src_start_freq,
|
| 812 |
start_subband, end_subband; |
| 813 |
|
| 814 |
/* determine which channels use spx */
|
| 815 |
if (s->channel_mode == AC3_CHMODE_MONO) {
|
| 816 |
s->channel_uses_spx[1] = 1; |
| 817 |
} else {
|
| 818 |
for (ch = 1; ch <= fbw_channels; ch++) |
| 819 |
s->channel_uses_spx[ch] = get_bits1(gbc); |
| 820 |
} |
| 821 |
|
| 822 |
/* get the frequency bins of the spx copy region and the spx start
|
| 823 |
and end subbands */
|
| 824 |
dst_start_freq = get_bits(gbc, 2);
|
| 825 |
start_subband = get_bits(gbc, 3) + 2; |
| 826 |
if (start_subband > 7) |
| 827 |
start_subband += start_subband - 7;
|
| 828 |
end_subband = get_bits(gbc, 3) + 5; |
| 829 |
if (end_subband > 7) |
| 830 |
end_subband += end_subband - 7;
|
| 831 |
dst_start_freq = dst_start_freq * 12 + 25; |
| 832 |
src_start_freq = start_subband * 12 + 25; |
| 833 |
dst_end_freq = end_subband * 12 + 25; |
| 834 |
|
| 835 |
/* check validity of spx ranges */
|
| 836 |
if (start_subband >= end_subband) {
|
| 837 |
av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
|
| 838 |
"range (%d >= %d)\n", start_subband, end_subband);
|
| 839 |
return -1; |
| 840 |
} |
| 841 |
if (dst_start_freq >= src_start_freq) {
|
| 842 |
av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
|
| 843 |
"copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
|
| 844 |
return -1; |
| 845 |
} |
| 846 |
|
| 847 |
s->spx_dst_start_freq = dst_start_freq; |
| 848 |
s->spx_src_start_freq = src_start_freq; |
| 849 |
s->spx_dst_end_freq = dst_end_freq; |
| 850 |
|
| 851 |
decode_band_structure(gbc, blk, s->eac3, 0,
|
| 852 |
start_subband, end_subband, |
| 853 |
ff_eac3_default_spx_band_struct, |
| 854 |
&s->num_spx_bands, |
| 855 |
s->spx_band_sizes); |
| 856 |
} else {
|
| 857 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 858 |
s->channel_uses_spx[ch] = 0;
|
| 859 |
s->first_spx_coords[ch] = 1;
|
| 860 |
} |
| 861 |
} |
| 862 |
} |
| 863 |
|
| 864 |
/* spectral extension coordinates */
|
| 865 |
if (s->spx_in_use) {
|
| 866 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 867 |
if (s->channel_uses_spx[ch]) {
|
| 868 |
if (s->first_spx_coords[ch] || get_bits1(gbc)) {
|
| 869 |
float spx_blend;
|
| 870 |
int bin, master_spx_coord;
|
| 871 |
|
| 872 |
s->first_spx_coords[ch] = 0;
|
| 873 |
spx_blend = get_bits(gbc, 5) * (1.0f/32); |
| 874 |
master_spx_coord = get_bits(gbc, 2) * 3; |
| 875 |
|
| 876 |
bin = s->spx_src_start_freq; |
| 877 |
for (bnd = 0; bnd < s->num_spx_bands; bnd++) { |
| 878 |
int bandsize;
|
| 879 |
int spx_coord_exp, spx_coord_mant;
|
| 880 |
float nratio, sblend, nblend, spx_coord;
|
| 881 |
|
| 882 |
/* calculate blending factors */
|
| 883 |
bandsize = s->spx_band_sizes[bnd]; |
| 884 |
nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend; |
| 885 |
nratio = av_clipf(nratio, 0.0f, 1.0f); |
| 886 |
nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3) to give unity variance |
| 887 |
sblend = sqrtf(1.0f - nratio); |
| 888 |
bin += bandsize; |
| 889 |
|
| 890 |
/* decode spx coordinates */
|
| 891 |
spx_coord_exp = get_bits(gbc, 4);
|
| 892 |
spx_coord_mant = get_bits(gbc, 2);
|
| 893 |
if (spx_coord_exp == 15) spx_coord_mant <<= 1; |
| 894 |
else spx_coord_mant += 4; |
| 895 |
spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
|
| 896 |
spx_coord = spx_coord_mant * (1.0f/(1<<23)); |
| 897 |
|
| 898 |
/* multiply noise and signal blending factors by spx coordinate */
|
| 899 |
s->spx_noise_blend [ch][bnd] = nblend * spx_coord; |
| 900 |
s->spx_signal_blend[ch][bnd] = sblend * spx_coord; |
| 901 |
} |
| 902 |
} |
| 903 |
} else {
|
| 904 |
s->first_spx_coords[ch] = 1;
|
| 905 |
} |
| 906 |
} |
| 907 |
} |
| 908 |
|
| 909 |
/* coupling strategy */
|
| 910 |
if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
|
| 911 |
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
|
| 912 |
if (!s->eac3)
|
| 913 |
s->cpl_in_use[blk] = get_bits1(gbc); |
| 914 |
if (s->cpl_in_use[blk]) {
|
| 915 |
/* coupling in use */
|
| 916 |
int cpl_start_subband, cpl_end_subband;
|
| 917 |
|
| 918 |
if (channel_mode < AC3_CHMODE_STEREO) {
|
| 919 |
av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
|
| 920 |
return -1; |
| 921 |
} |
| 922 |
|
| 923 |
/* check for enhanced coupling */
|
| 924 |
if (s->eac3 && get_bits1(gbc)) {
|
| 925 |
/* TODO: parse enhanced coupling strategy info */
|
| 926 |
av_log_missing_feature(s->avctx, "Enhanced coupling", 1); |
| 927 |
return -1; |
| 928 |
} |
| 929 |
|
| 930 |
/* determine which channels are coupled */
|
| 931 |
if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
|
| 932 |
s->channel_in_cpl[1] = 1; |
| 933 |
s->channel_in_cpl[2] = 1; |
| 934 |
} else {
|
| 935 |
for (ch = 1; ch <= fbw_channels; ch++) |
| 936 |
s->channel_in_cpl[ch] = get_bits1(gbc); |
| 937 |
} |
| 938 |
|
| 939 |
/* phase flags in use */
|
| 940 |
if (channel_mode == AC3_CHMODE_STEREO)
|
| 941 |
s->phase_flags_in_use = get_bits1(gbc); |
| 942 |
|
| 943 |
/* coupling frequency range */
|
| 944 |
cpl_start_subband = get_bits(gbc, 4);
|
| 945 |
cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 : |
| 946 |
get_bits(gbc, 4) + 3; |
| 947 |
if (cpl_start_subband >= cpl_end_subband) {
|
| 948 |
av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
|
| 949 |
cpl_start_subband, cpl_end_subband); |
| 950 |
return -1; |
| 951 |
} |
| 952 |
s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37; |
| 953 |
s->end_freq[CPL_CH] = cpl_end_subband * 12 + 37; |
| 954 |
|
| 955 |
decode_band_structure(gbc, blk, s->eac3, 0, cpl_start_subband,
|
| 956 |
cpl_end_subband, |
| 957 |
ff_eac3_default_cpl_band_struct, |
| 958 |
&s->num_cpl_bands, s->cpl_band_sizes); |
| 959 |
} else {
|
| 960 |
/* coupling not in use */
|
| 961 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 962 |
s->channel_in_cpl[ch] = 0;
|
| 963 |
s->first_cpl_coords[ch] = 1;
|
| 964 |
} |
| 965 |
s->first_cpl_leak = s->eac3; |
| 966 |
s->phase_flags_in_use = 0;
|
| 967 |
} |
| 968 |
} else if (!s->eac3) { |
| 969 |
if(!blk) {
|
| 970 |
av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
|
| 971 |
return -1; |
| 972 |
} else {
|
| 973 |
s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
|
| 974 |
} |
| 975 |
} |
| 976 |
cpl_in_use = s->cpl_in_use[blk]; |
| 977 |
|
| 978 |
/* coupling coordinates */
|
| 979 |
if (cpl_in_use) {
|
| 980 |
int cpl_coords_exist = 0; |
| 981 |
|
| 982 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 983 |
if (s->channel_in_cpl[ch]) {
|
| 984 |
if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) {
|
| 985 |
int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
|
| 986 |
s->first_cpl_coords[ch] = 0;
|
| 987 |
cpl_coords_exist = 1;
|
| 988 |
master_cpl_coord = 3 * get_bits(gbc, 2); |
| 989 |
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { |
| 990 |
cpl_coord_exp = get_bits(gbc, 4);
|
| 991 |
cpl_coord_mant = get_bits(gbc, 4);
|
| 992 |
if (cpl_coord_exp == 15) |
| 993 |
s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
|
| 994 |
else
|
| 995 |
s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21; |
| 996 |
s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord); |
| 997 |
} |
| 998 |
} else if (!blk) { |
| 999 |
av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must be present in block 0\n");
|
| 1000 |
return -1; |
| 1001 |
} |
| 1002 |
} else {
|
| 1003 |
/* channel not in coupling */
|
| 1004 |
s->first_cpl_coords[ch] = 1;
|
| 1005 |
} |
| 1006 |
} |
| 1007 |
/* phase flags */
|
| 1008 |
if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
|
| 1009 |
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) { |
| 1010 |
s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
|
| 1011 |
} |
| 1012 |
} |
| 1013 |
} |
| 1014 |
|
| 1015 |
/* stereo rematrixing strategy and band structure */
|
| 1016 |
if (channel_mode == AC3_CHMODE_STEREO) {
|
| 1017 |
if ((s->eac3 && !blk) || get_bits1(gbc)) {
|
| 1018 |
s->num_rematrixing_bands = 4;
|
| 1019 |
if (cpl_in_use && s->start_freq[CPL_CH] <= 61) { |
| 1020 |
s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37); |
| 1021 |
} else if (s->spx_in_use && s->spx_src_start_freq <= 61) { |
| 1022 |
s->num_rematrixing_bands--; |
| 1023 |
} |
| 1024 |
for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) |
| 1025 |
s->rematrixing_flags[bnd] = get_bits1(gbc); |
| 1026 |
} else if (!blk) { |
| 1027 |
av_log(s->avctx, AV_LOG_WARNING, "Warning: new rematrixing strategy not present in block 0\n");
|
| 1028 |
s->num_rematrixing_bands = 0;
|
| 1029 |
} |
| 1030 |
} |
| 1031 |
|
| 1032 |
/* exponent strategies for each channel */
|
| 1033 |
for (ch = !cpl_in_use; ch <= s->channels; ch++) {
|
| 1034 |
if (!s->eac3)
|
| 1035 |
s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
|
| 1036 |
if(s->exp_strategy[blk][ch] != EXP_REUSE)
|
| 1037 |
bit_alloc_stages[ch] = 3;
|
| 1038 |
} |
| 1039 |
|
| 1040 |
/* channel bandwidth */
|
| 1041 |
for (ch = 1; ch <= fbw_channels; ch++) { |
| 1042 |
s->start_freq[ch] = 0;
|
| 1043 |
if (s->exp_strategy[blk][ch] != EXP_REUSE) {
|
| 1044 |
int group_size;
|
| 1045 |
int prev = s->end_freq[ch];
|
| 1046 |
if (s->channel_in_cpl[ch])
|
| 1047 |
s->end_freq[ch] = s->start_freq[CPL_CH]; |
| 1048 |
else if (s->channel_uses_spx[ch]) |
| 1049 |
s->end_freq[ch] = s->spx_src_start_freq; |
| 1050 |
else {
|
| 1051 |
int bandwidth_code = get_bits(gbc, 6); |
| 1052 |
if (bandwidth_code > 60) { |
| 1053 |
av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
|
| 1054 |
return -1; |
| 1055 |
} |
| 1056 |
s->end_freq[ch] = bandwidth_code * 3 + 73; |
| 1057 |
} |
| 1058 |
group_size = 3 << (s->exp_strategy[blk][ch] - 1); |
| 1059 |
s->num_exp_groups[ch] = (s->end_freq[ch]+group_size-4) / group_size;
|
| 1060 |
if(blk > 0 && s->end_freq[ch] != prev) |
| 1061 |
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
|
| 1062 |
} |
| 1063 |
} |
| 1064 |
if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
|
| 1065 |
s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) / |
| 1066 |
(3 << (s->exp_strategy[blk][CPL_CH] - 1)); |
| 1067 |
} |
| 1068 |
|
| 1069 |
/* decode exponents for each channel */
|
| 1070 |
for (ch = !cpl_in_use; ch <= s->channels; ch++) {
|
| 1071 |
if (s->exp_strategy[blk][ch] != EXP_REUSE) {
|
| 1072 |
s->dexps[ch][0] = get_bits(gbc, 4) << !ch; |
| 1073 |
if (decode_exponents(gbc, s->exp_strategy[blk][ch],
|
| 1074 |
s->num_exp_groups[ch], s->dexps[ch][0],
|
| 1075 |
&s->dexps[ch][s->start_freq[ch]+!!ch])) {
|
| 1076 |
av_log(s->avctx, AV_LOG_ERROR, "exponent out-of-range\n");
|
| 1077 |
return -1; |
| 1078 |
} |
| 1079 |
if(ch != CPL_CH && ch != s->lfe_ch)
|
| 1080 |
skip_bits(gbc, 2); /* skip gainrng */ |
| 1081 |
} |
| 1082 |
} |
| 1083 |
|
| 1084 |
/* bit allocation information */
|
| 1085 |
if (s->bit_allocation_syntax) {
|
| 1086 |
if (get_bits1(gbc)) {
|
| 1087 |
s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
|
| 1088 |
s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
|
| 1089 |
s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
|
| 1090 |
s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
|
| 1091 |
s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
|
| 1092 |
for(ch=!cpl_in_use; ch<=s->channels; ch++)
|
| 1093 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
|
| 1094 |
} else if (!blk) { |
| 1095 |
av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must be present in block 0\n");
|
| 1096 |
return -1; |
| 1097 |
} |
| 1098 |
} |
| 1099 |
|
| 1100 |
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
|
| 1101 |
if(!s->eac3 || !blk){
|
| 1102 |
if(s->snr_offset_strategy && get_bits1(gbc)) {
|
| 1103 |
int snr = 0; |
| 1104 |
int csnr;
|
| 1105 |
csnr = (get_bits(gbc, 6) - 15) << 4; |
| 1106 |
for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
|
| 1107 |
/* snr offset */
|
| 1108 |
if (ch == i || s->snr_offset_strategy == 2) |
| 1109 |
snr = (csnr + get_bits(gbc, 4)) << 2; |
| 1110 |
/* run at least last bit allocation stage if snr offset changes */
|
| 1111 |
if(blk && s->snr_offset[ch] != snr) {
|
| 1112 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
|
| 1113 |
} |
| 1114 |
s->snr_offset[ch] = snr; |
| 1115 |
|
| 1116 |
/* fast gain (normal AC-3 only) */
|
| 1117 |
if (!s->eac3) {
|
| 1118 |
int prev = s->fast_gain[ch];
|
| 1119 |
s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
|
| 1120 |
/* run last 2 bit allocation stages if fast gain changes */
|
| 1121 |
if(blk && prev != s->fast_gain[ch])
|
| 1122 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
|
| 1123 |
} |
| 1124 |
} |
| 1125 |
} else if (!s->eac3 && !blk) { |
| 1126 |
av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
|
| 1127 |
return -1; |
| 1128 |
} |
| 1129 |
} |
| 1130 |
|
| 1131 |
/* fast gain (E-AC-3 only) */
|
| 1132 |
if (s->fast_gain_syntax && get_bits1(gbc)) {
|
| 1133 |
for (ch = !cpl_in_use; ch <= s->channels; ch++) {
|
| 1134 |
int prev = s->fast_gain[ch];
|
| 1135 |
s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
|
| 1136 |
/* run last 2 bit allocation stages if fast gain changes */
|
| 1137 |
if(blk && prev != s->fast_gain[ch])
|
| 1138 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
|
| 1139 |
} |
| 1140 |
} else if (s->eac3 && !blk) { |
| 1141 |
for (ch = !cpl_in_use; ch <= s->channels; ch++)
|
| 1142 |
s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
|
| 1143 |
} |
| 1144 |
|
| 1145 |
/* E-AC-3 to AC-3 converter SNR offset */
|
| 1146 |
if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
|
| 1147 |
skip_bits(gbc, 10); // skip converter snr offset |
| 1148 |
} |
| 1149 |
|
| 1150 |
/* coupling leak information */
|
| 1151 |
if (cpl_in_use) {
|
| 1152 |
if (s->first_cpl_leak || get_bits1(gbc)) {
|
| 1153 |
int fl = get_bits(gbc, 3); |
| 1154 |
int sl = get_bits(gbc, 3); |
| 1155 |
/* run last 2 bit allocation stages for coupling channel if
|
| 1156 |
coupling leak changes */
|
| 1157 |
if(blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
|
| 1158 |
sl != s->bit_alloc_params.cpl_slow_leak)) {
|
| 1159 |
bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
|
| 1160 |
} |
| 1161 |
s->bit_alloc_params.cpl_fast_leak = fl; |
| 1162 |
s->bit_alloc_params.cpl_slow_leak = sl; |
| 1163 |
} else if (!s->eac3 && !blk) { |
| 1164 |
av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must be present in block 0\n");
|
| 1165 |
return -1; |
| 1166 |
} |
| 1167 |
s->first_cpl_leak = 0;
|
| 1168 |
} |
| 1169 |
|
| 1170 |
/* delta bit allocation information */
|
| 1171 |
if (s->dba_syntax && get_bits1(gbc)) {
|
| 1172 |
/* delta bit allocation exists (strategy) */
|
| 1173 |
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
|
| 1174 |
s->dba_mode[ch] = get_bits(gbc, 2);
|
| 1175 |
if (s->dba_mode[ch] == DBA_RESERVED) {
|
| 1176 |
av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
|
| 1177 |
return -1; |
| 1178 |
} |
| 1179 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
|
| 1180 |
} |
| 1181 |
/* channel delta offset, len and bit allocation */
|
| 1182 |
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
|
| 1183 |
if (s->dba_mode[ch] == DBA_NEW) {
|
| 1184 |
s->dba_nsegs[ch] = get_bits(gbc, 3);
|
| 1185 |
for (seg = 0; seg <= s->dba_nsegs[ch]; seg++) { |
| 1186 |
s->dba_offsets[ch][seg] = get_bits(gbc, 5);
|
| 1187 |
s->dba_lengths[ch][seg] = get_bits(gbc, 4);
|
| 1188 |
s->dba_values[ch][seg] = get_bits(gbc, 3);
|
| 1189 |
} |
| 1190 |
/* run last 2 bit allocation stages if new dba values */
|
| 1191 |
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
|
| 1192 |
} |
| 1193 |
} |
| 1194 |
} else if(blk == 0) { |
| 1195 |
for(ch=0; ch<=s->channels; ch++) { |
| 1196 |
s->dba_mode[ch] = DBA_NONE; |
| 1197 |
} |
| 1198 |
} |
| 1199 |
|
| 1200 |
/* Bit allocation */
|
| 1201 |
for(ch=!cpl_in_use; ch<=s->channels; ch++) {
|
| 1202 |
if(bit_alloc_stages[ch] > 2) { |
| 1203 |
/* Exponent mapping into PSD and PSD integration */
|
| 1204 |
ff_ac3_bit_alloc_calc_psd(s->dexps[ch], |
| 1205 |
s->start_freq[ch], s->end_freq[ch], |
| 1206 |
s->psd[ch], s->band_psd[ch]); |
| 1207 |
} |
| 1208 |
if(bit_alloc_stages[ch] > 1) { |
| 1209 |
/* Compute excitation function, Compute masking curve, and
|
| 1210 |
Apply delta bit allocation */
|
| 1211 |
if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
|
| 1212 |
s->start_freq[ch], s->end_freq[ch], |
| 1213 |
s->fast_gain[ch], (ch == s->lfe_ch), |
| 1214 |
s->dba_mode[ch], s->dba_nsegs[ch], |
| 1215 |
s->dba_offsets[ch], s->dba_lengths[ch], |
| 1216 |
s->dba_values[ch], s->mask[ch])) {
|
| 1217 |
av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n");
|
| 1218 |
return -1; |
| 1219 |
} |
| 1220 |
} |
| 1221 |
if(bit_alloc_stages[ch] > 0) { |
| 1222 |
/* Compute bit allocation */
|
| 1223 |
const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
|
| 1224 |
ff_eac3_hebap_tab : ff_ac3_bap_tab; |
| 1225 |
ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch], |
| 1226 |
s->start_freq[ch], s->end_freq[ch], |
| 1227 |
s->snr_offset[ch], |
| 1228 |
s->bit_alloc_params.floor, |
| 1229 |
bap_tab, s->bap[ch]); |
| 1230 |
} |
| 1231 |
} |
| 1232 |
|
| 1233 |
/* unused dummy data */
|
| 1234 |
if (s->skip_syntax && get_bits1(gbc)) {
|
| 1235 |
int skipl = get_bits(gbc, 9); |
| 1236 |
while(skipl--)
|
| 1237 |
skip_bits(gbc, 8);
|
| 1238 |
} |
| 1239 |
|
| 1240 |
/* unpack the transform coefficients
|
| 1241 |
this also uncouples channels if coupling is in use. */
|
| 1242 |
decode_transform_coeffs(s, blk); |
| 1243 |
|
| 1244 |
/* TODO: generate enhanced coupling coordinates and uncouple */
|
| 1245 |
|
| 1246 |
/* recover coefficients if rematrixing is in use */
|
| 1247 |
if(s->channel_mode == AC3_CHMODE_STEREO)
|
| 1248 |
do_rematrixing(s); |
| 1249 |
|
| 1250 |
/* apply scaling to coefficients (headroom, dynrng) */
|
| 1251 |
for(ch=1; ch<=s->channels; ch++) { |
| 1252 |
float gain = s->mul_bias / 4194304.0f; |
| 1253 |
if(s->channel_mode == AC3_CHMODE_DUALMONO) {
|
| 1254 |
gain *= s->dynamic_range[2-ch];
|
| 1255 |
} else {
|
| 1256 |
gain *= s->dynamic_range[0];
|
| 1257 |
} |
| 1258 |
s->dsp.int32_to_float_fmul_scalar(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
|
| 1259 |
} |
| 1260 |
|
| 1261 |
/* apply spectral extension to high frequency bins */
|
| 1262 |
if (s->spx_in_use && CONFIG_EAC3_DECODER) {
|
| 1263 |
ff_eac3_apply_spectral_extension(s); |
| 1264 |
} |
| 1265 |
|
| 1266 |
/* downmix and MDCT. order depends on whether block switching is used for
|
| 1267 |
any channel in this block. this is because coefficients for the long
|
| 1268 |
and short transforms cannot be mixed. */
|
| 1269 |
downmix_output = s->channels != s->out_channels && |
| 1270 |
!((s->output_mode & AC3_OUTPUT_LFEON) && |
| 1271 |
s->fbw_channels == s->out_channels); |
| 1272 |
if(different_transforms) {
|
| 1273 |
/* the delay samples have already been downmixed, so we upmix the delay
|
| 1274 |
samples in order to reconstruct all channels before downmixing. */
|
| 1275 |
if(s->downmixed) {
|
| 1276 |
s->downmixed = 0;
|
| 1277 |
ac3_upmix_delay(s); |
| 1278 |
} |
| 1279 |
|
| 1280 |
do_imdct(s, s->channels); |
| 1281 |
|
| 1282 |
if(downmix_output) {
|
| 1283 |
s->dsp.ac3_downmix(s->output, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256);
|
| 1284 |
} |
| 1285 |
} else {
|
| 1286 |
if(downmix_output) {
|
| 1287 |
s->dsp.ac3_downmix(s->transform_coeffs+1, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256); |
| 1288 |
} |
| 1289 |
|
| 1290 |
if(downmix_output && !s->downmixed) {
|
| 1291 |
s->downmixed = 1;
|
| 1292 |
s->dsp.ac3_downmix(s->delay, s->downmix_coeffs, s->out_channels, s->fbw_channels, 128);
|
| 1293 |
} |
| 1294 |
|
| 1295 |
do_imdct(s, s->out_channels); |
| 1296 |
} |
| 1297 |
|
| 1298 |
return 0; |
| 1299 |
} |
| 1300 |
|
| 1301 |
/**
|
| 1302 |
* Decode a single AC-3 frame.
|
| 1303 |
*/
|
| 1304 |
static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, |
| 1305 |
AVPacket *avpkt) |
| 1306 |
{
|
| 1307 |
const uint8_t *buf = avpkt->data;
|
| 1308 |
int buf_size = avpkt->size;
|
| 1309 |
AC3DecodeContext *s = avctx->priv_data; |
| 1310 |
int16_t *out_samples = (int16_t *)data; |
| 1311 |
int blk, ch, err;
|
| 1312 |
const uint8_t *channel_map;
|
| 1313 |
const float *output[AC3_MAX_CHANNELS]; |
| 1314 |
|
| 1315 |
/* initialize the GetBitContext with the start of valid AC-3 Frame */
|
| 1316 |
if (s->input_buffer) {
|
| 1317 |
/* copy input buffer to decoder context to avoid reading past the end
|
| 1318 |
of the buffer, which can be caused by a damaged input stream. */
|
| 1319 |
memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE)); |
| 1320 |
init_get_bits(&s->gbc, s->input_buffer, buf_size * 8);
|
| 1321 |
} else {
|
| 1322 |
init_get_bits(&s->gbc, buf, buf_size * 8);
|
| 1323 |
} |
| 1324 |
|
| 1325 |
/* parse the syncinfo */
|
| 1326 |
*data_size = 0;
|
| 1327 |
err = parse_frame_header(s); |
| 1328 |
|
| 1329 |
if (err) {
|
| 1330 |
switch(err) {
|
| 1331 |
case AAC_AC3_PARSE_ERROR_SYNC:
|
| 1332 |
av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
|
| 1333 |
return -1; |
| 1334 |
case AAC_AC3_PARSE_ERROR_BSID:
|
| 1335 |
av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
|
| 1336 |
break;
|
| 1337 |
case AAC_AC3_PARSE_ERROR_SAMPLE_RATE:
|
| 1338 |
av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
|
| 1339 |
break;
|
| 1340 |
case AAC_AC3_PARSE_ERROR_FRAME_SIZE:
|
| 1341 |
av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
|
| 1342 |
break;
|
| 1343 |
case AAC_AC3_PARSE_ERROR_FRAME_TYPE:
|
| 1344 |
/* skip frame if CRC is ok. otherwise use error concealment. */
|
| 1345 |
/* TODO: add support for substreams and dependent frames */
|
| 1346 |
if(s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) {
|
| 1347 |
av_log(avctx, AV_LOG_ERROR, "unsupported frame type : skipping frame\n");
|
| 1348 |
return s->frame_size;
|
| 1349 |
} else {
|
| 1350 |
av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
|
| 1351 |
} |
| 1352 |
break;
|
| 1353 |
default:
|
| 1354 |
av_log(avctx, AV_LOG_ERROR, "invalid header\n");
|
| 1355 |
break;
|
| 1356 |
} |
| 1357 |
} else {
|
| 1358 |
/* check that reported frame size fits in input buffer */
|
| 1359 |
if (s->frame_size > buf_size) {
|
| 1360 |
av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
|
| 1361 |
err = AAC_AC3_PARSE_ERROR_FRAME_SIZE; |
| 1362 |
} else if (avctx->error_recognition >= FF_ER_CAREFUL) { |
| 1363 |
/* check for crc mismatch */
|
| 1364 |
if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) { |
| 1365 |
av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
|
| 1366 |
err = AAC_AC3_PARSE_ERROR_CRC; |
| 1367 |
} |
| 1368 |
} |
| 1369 |
} |
| 1370 |
|
| 1371 |
/* if frame is ok, set audio parameters */
|
| 1372 |
if (!err) {
|
| 1373 |
avctx->sample_rate = s->sample_rate; |
| 1374 |
avctx->bit_rate = s->bit_rate; |
| 1375 |
|
| 1376 |
/* channel config */
|
| 1377 |
s->out_channels = s->channels; |
| 1378 |
s->output_mode = s->channel_mode; |
| 1379 |
if(s->lfe_on)
|
| 1380 |
s->output_mode |= AC3_OUTPUT_LFEON; |
| 1381 |
if (avctx->request_channels > 0 && avctx->request_channels <= 2 && |
| 1382 |
avctx->request_channels < s->channels) {
|
| 1383 |
s->out_channels = avctx->request_channels; |
| 1384 |
s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
|
| 1385 |
s->channel_layout = ff_ac3_channel_layout_tab[s->output_mode]; |
| 1386 |
} |
| 1387 |
avctx->channels = s->out_channels; |
| 1388 |
avctx->channel_layout = s->channel_layout; |
| 1389 |
|
| 1390 |
/* set downmixing coefficients if needed */
|
| 1391 |
if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
|
| 1392 |
s->fbw_channels == s->out_channels)) {
|
| 1393 |
set_downmix_coeffs(s); |
| 1394 |
} |
| 1395 |
} else if (!s->out_channels) { |
| 1396 |
s->out_channels = avctx->channels; |
| 1397 |
if(s->out_channels < s->channels)
|
| 1398 |
s->output_mode = s->out_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
|
| 1399 |
} |
| 1400 |
|
| 1401 |
/* decode the audio blocks */
|
| 1402 |
channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on]; |
| 1403 |
for (ch = 0; ch < s->out_channels; ch++) |
| 1404 |
output[ch] = s->output[channel_map[ch]]; |
| 1405 |
for (blk = 0; blk < s->num_blocks; blk++) { |
| 1406 |
if (!err && decode_audio_block(s, blk)) {
|
| 1407 |
av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
|
| 1408 |
err = 1;
|
| 1409 |
} |
| 1410 |
s->dsp.float_to_int16_interleave(out_samples, output, 256, s->out_channels);
|
| 1411 |
out_samples += 256 * s->out_channels;
|
| 1412 |
} |
| 1413 |
*data_size = s->num_blocks * 256 * avctx->channels * sizeof (int16_t); |
| 1414 |
return FFMIN(buf_size, s->frame_size);
|
| 1415 |
} |
| 1416 |
|
| 1417 |
/**
|
| 1418 |
* Uninitialize the AC-3 decoder.
|
| 1419 |
*/
|
| 1420 |
static av_cold int ac3_decode_end(AVCodecContext *avctx) |
| 1421 |
{
|
| 1422 |
AC3DecodeContext *s = avctx->priv_data; |
| 1423 |
ff_mdct_end(&s->imdct_512); |
| 1424 |
ff_mdct_end(&s->imdct_256); |
| 1425 |
|
| 1426 |
av_freep(&s->input_buffer); |
| 1427 |
|
| 1428 |
return 0; |
| 1429 |
} |
| 1430 |
|
| 1431 |
AVCodec ff_ac3_decoder = {
|
| 1432 |
.name = "ac3",
|
| 1433 |
.type = AVMEDIA_TYPE_AUDIO, |
| 1434 |
.id = CODEC_ID_AC3, |
| 1435 |
.priv_data_size = sizeof (AC3DecodeContext),
|
| 1436 |
.init = ac3_decode_init, |
| 1437 |
.close = ac3_decode_end, |
| 1438 |
.decode = ac3_decode_frame, |
| 1439 |
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
|
| 1440 |
}; |
| 1441 |
|
| 1442 |
#if CONFIG_EAC3_DECODER
|
| 1443 |
AVCodec ff_eac3_decoder = {
|
| 1444 |
.name = "eac3",
|
| 1445 |
.type = AVMEDIA_TYPE_AUDIO, |
| 1446 |
.id = CODEC_ID_EAC3, |
| 1447 |
.priv_data_size = sizeof (AC3DecodeContext),
|
| 1448 |
.init = ac3_decode_init, |
| 1449 |
.close = ac3_decode_end, |
| 1450 |
.decode = ac3_decode_frame, |
| 1451 |
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
|
| 1452 |
}; |
| 1453 |
#endif
|