1/* 2 * Copyright (c) 2007 Ian Caulfield 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21#include <stdint.h> 22 23#include "libavutil/channel_layout.h" 24#include "get_bits.h" 25#include "mlp_parse.h" 26#include "mlp.h" 27 28static const uint8_t mlp_quants[16] = { 29 16, 20, 24, 0, 0, 0, 0, 0, 30 0, 0, 0, 0, 0, 0, 0, 0, 31}; 32 33static const uint8_t mlp_channels[32] = { 34 1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4, 35 5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 36}; 37 38static const uint64_t mlp_layout[32] = { 39 AV_CH_LAYOUT_MONO, 40 AV_CH_LAYOUT_STEREO, 41 AV_CH_LAYOUT_2_1, 42 AV_CH_LAYOUT_QUAD, 43 AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY, 44 AV_CH_LAYOUT_2_1|AV_CH_LOW_FREQUENCY, 45 AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY, 46 AV_CH_LAYOUT_SURROUND, 47 AV_CH_LAYOUT_4POINT0, 48 AV_CH_LAYOUT_5POINT0_BACK, 49 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY, 50 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY, 51 AV_CH_LAYOUT_5POINT1_BACK, 52 AV_CH_LAYOUT_4POINT0, 53 AV_CH_LAYOUT_5POINT0_BACK, 54 AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY, 55 AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY, 56 AV_CH_LAYOUT_5POINT1_BACK, 57 AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY, 58 AV_CH_LAYOUT_5POINT0_BACK, 59 AV_CH_LAYOUT_5POINT1_BACK, 60 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 61}; 62 63static int mlp_get_major_sync_size(const uint8_t * buf, int bufsize) 64{ 65 int has_extension, extensions = 0; 66 int size = 28; 67 if (bufsize < 28) 68 return -1; 69 70 if (AV_RB32(buf) == 0xf8726fba) { 71 has_extension = buf[25] & 1; 72 if (has_extension) { 73 extensions = buf[26] >> 4; 74 size += 2 + extensions * 2; 75 } 76 } 77 return size; 78} 79 80/** Read a major sync info header - contains high level information about 81 * the stream - sample rate, channel arrangement etc. Most of this 82 * information is not actually necessary for decoding, only for playback. 83 * gb must be a freshly initialized GetBitContext with no bits read. 84 */ 85 86int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb) 87{ 88 int ratebits, channel_arrangement, header_size; 89 uint16_t checksum; 90 91 av_assert1(get_bits_count(gb) == 0); 92 93 header_size = mlp_get_major_sync_size(gb->buffer, gb->size_in_bits >> 3); 94 if (header_size < 0 || gb->size_in_bits < header_size << 3) { 95 av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n"); 96 return -1; 97 } 98 99 checksum = ff_mlp_checksum16(gb->buffer, header_size - 2); 100 if (checksum != AV_RL16(gb->buffer+header_size-2)) { 101 av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n"); 102 return AVERROR_INVALIDDATA; 103 } 104 105 if (get_bits(gb, 24) != 0xf8726f) /* Sync words */ 106 return AVERROR_INVALIDDATA; 107 108 mh->stream_type = get_bits(gb, 8); 109 mh->header_size = header_size; 110 111 if (mh->stream_type == 0xbb) { 112 mh->group1_bits = mlp_quants[get_bits(gb, 4)]; 113 mh->group2_bits = mlp_quants[get_bits(gb, 4)]; 114 115 ratebits = get_bits(gb, 4); 116 mh->group1_samplerate = mlp_samplerate(ratebits); 117 mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4)); 118 119 skip_bits(gb, 11); 120 121 mh->channel_arrangement= 122 channel_arrangement = get_bits(gb, 5); 123 mh->channels_mlp = mlp_channels[channel_arrangement]; 124 mh->channel_layout_mlp = mlp_layout[channel_arrangement]; 125 } else if (mh->stream_type == 0xba) { 126 mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere? 127 mh->group2_bits = 0; 128 129 ratebits = get_bits(gb, 4); 130 mh->group1_samplerate = mlp_samplerate(ratebits); 131 mh->group2_samplerate = 0; 132 133 skip_bits(gb, 4); 134 135 mh->channel_modifier_thd_stream0 = get_bits(gb, 2); 136 mh->channel_modifier_thd_stream1 = get_bits(gb, 2); 137 138 mh->channel_arrangement= 139 channel_arrangement = get_bits(gb, 5); 140 mh->channels_thd_stream1 = truehd_channels(channel_arrangement); 141 mh->channel_layout_thd_stream1 = truehd_layout(channel_arrangement); 142 143 mh->channel_modifier_thd_stream2 = get_bits(gb, 2); 144 145 channel_arrangement = get_bits(gb, 13); 146 mh->channels_thd_stream2 = truehd_channels(channel_arrangement); 147 mh->channel_layout_thd_stream2 = truehd_layout(channel_arrangement); 148 } else 149 return AVERROR_INVALIDDATA; 150 151 mh->access_unit_size = 40 << (ratebits & 7); 152 mh->access_unit_size_pow2 = 64 << (ratebits & 7); 153 154 skip_bits_long(gb, 48); 155 156 mh->is_vbr = get_bits1(gb); 157 158 mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4; 159 160 mh->num_substreams = get_bits(gb, 4); 161 162 skip_bits_long(gb, 4 + (header_size - 17) * 8); 163 164 return 0; 165} 166