| 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 | */ |
| 33 | static 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 | |
| 55 | /* XXX: make sure to update the copies in the different encoders if you change |
| 56 | * this table */ |
| 57 | const int avpriv_mpeg4audio_sample_rates[16] = { |
| 58 | 96000, 88200, 64000, 48000, 44100, 32000, |
| 59 | 24000, 22050, 16000, 12000, 11025, 8000, 7350 |
| 60 | }; |
| 61 | |
| 62 | const uint8_t ff_mpeg4audio_channels[8] = { |
| 63 | 0, 1, 2, 3, 4, 5, 6, 8 |
| 64 | }; |
| 65 | |
| 66 | static inline int get_object_type(GetBitContext *gb) |
| 67 | { |
| 68 | int object_type = get_bits(gb, 5); |
| 69 | if (object_type == AOT_ESCAPE) |
| 70 | object_type = 32 + get_bits(gb, 6); |
| 71 | return object_type; |
| 72 | } |
| 73 | |
| 74 | static inline int get_sample_rate(GetBitContext *gb, int *index) |
| 75 | { |
| 76 | *index = get_bits(gb, 4); |
| 77 | return *index == 0x0f ? get_bits(gb, 24) : |
| 78 | avpriv_mpeg4audio_sample_rates[*index]; |
| 79 | } |
| 80 | |
| 81 | int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, |
| 82 | int bit_size, int sync_extension) |
| 83 | { |
| 84 | GetBitContext gb; |
| 85 | int specific_config_bitindex; |
| 86 | |
| 87 | if (bit_size <= 0 || init_get_bits(&gb, buf, bit_size) < 0) |
| 88 | return AVERROR_INVALIDDATA; |
| 89 | c->object_type = get_object_type(&gb); |
| 90 | c->sample_rate = get_sample_rate(&gb, &c->sampling_index); |
| 91 | c->chan_config = get_bits(&gb, 4); |
| 92 | if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels)) |
| 93 | c->channels = ff_mpeg4audio_channels[c->chan_config]; |
| 94 | c->sbr = -1; |
| 95 | c->ps = -1; |
| 96 | if (c->object_type == AOT_SBR || (c->object_type == AOT_PS && |
| 97 | // check for W6132 Annex YYYY draft MP3onMP4 |
| 98 | !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) { |
| 99 | if (c->object_type == AOT_PS) |
| 100 | c->ps = 1; |
| 101 | c->ext_object_type = AOT_SBR; |
| 102 | c->sbr = 1; |
| 103 | c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); |
| 104 | c->object_type = get_object_type(&gb); |
| 105 | if (c->object_type == AOT_ER_BSAC) |
| 106 | c->ext_chan_config = get_bits(&gb, 4); |
| 107 | } else { |
| 108 | c->ext_object_type = AOT_NULL; |
| 109 | c->ext_sample_rate = 0; |
| 110 | } |
| 111 | specific_config_bitindex = get_bits_count(&gb); |
| 112 | |
| 113 | if (c->object_type == AOT_ALS) { |
| 114 | skip_bits(&gb, 5); |
| 115 | if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S')) |
| 116 | skip_bits_long(&gb, 24); |
| 117 | |
| 118 | specific_config_bitindex = get_bits_count(&gb); |
| 119 | |
| 120 | if (parse_config_ALS(&gb, c)) |
| 121 | return -1; |
| 122 | } |
| 123 | |
| 124 | if (c->ext_object_type != AOT_SBR && sync_extension) { |
| 125 | while (get_bits_left(&gb) > 15) { |
| 126 | if (show_bits(&gb, 11) == 0x2b7) { // sync extension |
| 127 | get_bits(&gb, 11); |
| 128 | c->ext_object_type = get_object_type(&gb); |
| 129 | if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) { |
| 130 | c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); |
| 131 | if (c->ext_sample_rate == c->sample_rate) |
| 132 | c->sbr = -1; |
| 133 | } |
| 134 | if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548) |
| 135 | c->ps = get_bits1(&gb); |
| 136 | break; |
| 137 | } else |
| 138 | get_bits1(&gb); // skip 1 bit |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | //PS requires SBR |
| 143 | if (!c->sbr) |
| 144 | c->ps = 0; |
| 145 | //Limit implicit PS to the HE-AACv2 Profile |
| 146 | if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01) |
| 147 | c->ps = 0; |
| 148 | |
| 149 | return specific_config_bitindex; |
| 150 | } |
| 151 | |
| 152 | static av_always_inline unsigned int copy_bits(PutBitContext *pb, |
| 153 | GetBitContext *gb, |
| 154 | int bits) |
| 155 | { |
| 156 | unsigned int el = get_bits(gb, bits); |
| 157 | put_bits(pb, bits, el); |
| 158 | return el; |
| 159 | } |
| 160 | |
| 161 | int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb) |
| 162 | { |
| 163 | int five_bit_ch, four_bit_ch, comment_size, bits; |
| 164 | int offset = put_bits_count(pb); |
| 165 | |
| 166 | copy_bits(pb, gb, 10); //Tag, Object Type, Frequency |
| 167 | five_bit_ch = copy_bits(pb, gb, 4); //Front |
| 168 | five_bit_ch += copy_bits(pb, gb, 4); //Side |
| 169 | five_bit_ch += copy_bits(pb, gb, 4); //Back |
| 170 | four_bit_ch = copy_bits(pb, gb, 2); //LFE |
| 171 | four_bit_ch += copy_bits(pb, gb, 3); //Data |
| 172 | five_bit_ch += copy_bits(pb, gb, 4); //Coupling |
| 173 | if (copy_bits(pb, gb, 1)) //Mono Mixdown |
| 174 | copy_bits(pb, gb, 4); |
| 175 | if (copy_bits(pb, gb, 1)) //Stereo Mixdown |
| 176 | copy_bits(pb, gb, 4); |
| 177 | if (copy_bits(pb, gb, 1)) //Matrix Mixdown |
| 178 | copy_bits(pb, gb, 3); |
| 179 | for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16) |
| 180 | copy_bits(pb, gb, 16); |
| 181 | if (bits) |
| 182 | copy_bits(pb, gb, bits); |
| 183 | avpriv_align_put_bits(pb); |
| 184 | align_get_bits(gb); |
| 185 | comment_size = copy_bits(pb, gb, 8); |
| 186 | for (; comment_size > 0; comment_size--) |
| 187 | copy_bits(pb, gb, 8); |
| 188 | |
| 189 | return put_bits_count(pb) - offset; |
| 190 | } |