1/* 2 * MPEG-4 Audio common code 3 * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr> 4 * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "get_bits.h" 24#include "put_bits.h" 25#include "mpeg4audio.h" 26 27/** 28 * Parse MPEG-4 audio configuration for ALS object type. 29 * @param[in] gb bit reader context 30 * @param[in] c MPEG4AudioConfig structure to fill 31 * @return on success 0 is returned, otherwise a value < 0 32 */ 33static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c) 34{ 35 if (get_bits_left(gb) < 112) 36 return -1; 37 38 if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0')) 39 return -1; 40 41 // override AudioSpecificConfig channel configuration and sample rate 42 // which are buggy in old ALS conformance files 43 c->sample_rate = get_bits_long(gb, 32); 44 45 // skip number of samples 46 skip_bits_long(gb, 32); 47 48 // read number of channels 49 c->chan_config = 0; 50 c->channels = get_bits(gb, 16) + 1; 51 52 return 0; 53} 54 55const int ff_mpeg4audio_sample_rates[16] = { 56 96000, 88200, 64000, 48000, 44100, 32000, 57 24000, 22050, 16000, 12000, 11025, 8000, 7350 58}; 59 60const uint8_t ff_mpeg4audio_channels[8] = { 61 0, 1, 2, 3, 4, 5, 6, 8 62}; 63 64static inline int get_object_type(GetBitContext *gb) 65{ 66 int object_type = get_bits(gb, 5); 67 if (object_type == AOT_ESCAPE) 68 object_type = 32 + get_bits(gb, 6); 69 return object_type; 70} 71 72static inline int get_sample_rate(GetBitContext *gb, int *index) 73{ 74 *index = get_bits(gb, 4); 75 return *index == 0x0f ? get_bits(gb, 24) : 76 ff_mpeg4audio_sample_rates[*index]; 77} 78 79int ff_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, int buf_size) 80{ 81 GetBitContext gb; 82 int specific_config_bitindex; 83 84 init_get_bits(&gb, buf, buf_size*8); 85 c->object_type = get_object_type(&gb); 86 c->sample_rate = get_sample_rate(&gb, &c->sampling_index); 87 c->chan_config = get_bits(&gb, 4); 88 if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels)) 89 c->channels = ff_mpeg4audio_channels[c->chan_config]; 90 c->sbr = -1; 91 c->ps = -1; 92 if (c->object_type == AOT_SBR || (c->object_type == AOT_PS && 93 // check for W6132 Annex YYYY draft MP3onMP4 94 !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) { 95 if (c->object_type == AOT_PS) 96 c->ps = 1; 97 c->ext_object_type = AOT_SBR; 98 c->sbr = 1; 99 c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); 100 c->object_type = get_object_type(&gb); 101 if (c->object_type == AOT_ER_BSAC) 102 c->ext_chan_config = get_bits(&gb, 4); 103 } else { 104 c->ext_object_type = AOT_NULL; 105 c->ext_sample_rate = 0; 106 } 107 specific_config_bitindex = get_bits_count(&gb); 108 109 if (c->object_type == AOT_ALS) { 110 skip_bits(&gb, 5); 111 if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S')) 112 skip_bits_long(&gb, 24); 113 114 specific_config_bitindex = get_bits_count(&gb); 115 116 if (parse_config_ALS(&gb, c)) 117 return -1; 118 } 119 120 if (c->ext_object_type != AOT_SBR) { 121 while (get_bits_left(&gb) > 15) { 122 if (show_bits(&gb, 11) == 0x2b7) { // sync extension 123 get_bits(&gb, 11); 124 c->ext_object_type = get_object_type(&gb); 125 if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) 126 c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); 127 if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548) 128 c->ps = get_bits1(&gb); 129 break; 130 } else 131 get_bits1(&gb); // skip 1 bit 132 } 133 } 134 return specific_config_bitindex; 135} 136 137static av_always_inline unsigned int copy_bits(PutBitContext *pb, 138 GetBitContext *gb, 139 int bits) 140{ 141 unsigned int el = get_bits(gb, bits); 142 put_bits(pb, bits, el); 143 return el; 144} 145 146int ff_copy_pce_data(PutBitContext *pb, GetBitContext *gb) 147{ 148 int five_bit_ch, four_bit_ch, comment_size, bits; 149 int offset = put_bits_count(pb); 150 151 copy_bits(pb, gb, 10); //Tag, Object Type, Frequency 152 five_bit_ch = copy_bits(pb, gb, 4); //Front 153 five_bit_ch += copy_bits(pb, gb, 4); //Side 154 five_bit_ch += copy_bits(pb, gb, 4); //Back 155 four_bit_ch = copy_bits(pb, gb, 2); //LFE 156 four_bit_ch += copy_bits(pb, gb, 3); //Data 157 five_bit_ch += copy_bits(pb, gb, 4); //Coupling 158 if (copy_bits(pb, gb, 1)) //Mono Mixdown 159 copy_bits(pb, gb, 4); 160 if (copy_bits(pb, gb, 1)) //Stereo Mixdown 161 copy_bits(pb, gb, 4); 162 if (copy_bits(pb, gb, 1)) //Matrix Mixdown 163 copy_bits(pb, gb, 3); 164 for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16) 165 copy_bits(pb, gb, 16); 166 if (bits) 167 copy_bits(pb, gb, bits); 168 align_put_bits(pb); 169 align_get_bits(gb); 170 comment_size = copy_bits(pb, gb, 8); 171 for (; comment_size > 0; comment_size--) 172 copy_bits(pb, gb, 8); 173 174 return put_bits_count(pb) - offset; 175} 176