flac.c (7252B)
1 /* 2 * FLAC common code 3 * Copyright (c) 2009 Justin Ruggles 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 #include "libavutil/channel_layout.h" 23 #include "libavutil/crc.h" 24 #include "libavutil/log.h" 25 #include "bytestream.h" 26 #include "get_bits.h" 27 #include "flac.h" 28 #include "flacdata.h" 29 #include "flac_parse.h" 30 31 static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 32 }; 32 33 static const AVChannelLayout flac_channel_layouts[8] = { 34 AV_CHANNEL_LAYOUT_MONO, 35 AV_CHANNEL_LAYOUT_STEREO, 36 AV_CHANNEL_LAYOUT_SURROUND, 37 AV_CHANNEL_LAYOUT_QUAD, 38 AV_CHANNEL_LAYOUT_5POINT0, 39 AV_CHANNEL_LAYOUT_5POINT1, 40 AV_CHANNEL_LAYOUT_6POINT1, 41 AV_CHANNEL_LAYOUT_7POINT1 42 }; 43 44 static int64_t get_utf8(GetBitContext *gb) 45 { 46 int64_t val; 47 GET_UTF8(val, get_bits(gb, 8), return -1;) 48 return val; 49 } 50 51 int ff_flac_decode_frame_header(void *logctx, GetBitContext *gb, 52 FLACFrameInfo *fi, int log_level_offset) 53 { 54 int bs_code, sr_code, bps_code; 55 56 /* frame sync code */ 57 if ((get_bits(gb, 15) & 0x7FFF) != 0x7FFC) { 58 av_log(logctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n"); 59 return AVERROR_INVALIDDATA; 60 } 61 62 /* variable block size stream code */ 63 fi->is_var_size = get_bits1(gb); 64 65 /* block size and sample rate codes */ 66 bs_code = get_bits(gb, 4); 67 sr_code = get_bits(gb, 4); 68 69 /* channels and decorrelation */ 70 fi->ch_mode = get_bits(gb, 4); 71 if (fi->ch_mode < FLAC_MAX_CHANNELS) { 72 fi->channels = fi->ch_mode + 1; 73 fi->ch_mode = FLAC_CHMODE_INDEPENDENT; 74 } else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) { 75 fi->channels = 2; 76 fi->ch_mode -= FLAC_MAX_CHANNELS - 1; 77 } else { 78 av_log(logctx, AV_LOG_ERROR + log_level_offset, 79 "invalid channel mode: %d\n", fi->ch_mode); 80 return AVERROR_INVALIDDATA; 81 } 82 83 /* bits per sample */ 84 bps_code = get_bits(gb, 3); 85 if (bps_code == 3) { 86 av_log(logctx, AV_LOG_ERROR + log_level_offset, 87 "invalid sample size code (%d)\n", 88 bps_code); 89 return AVERROR_INVALIDDATA; 90 } 91 fi->bps = sample_size_table[bps_code]; 92 93 /* reserved bit */ 94 if (get_bits1(gb)) { 95 av_log(logctx, AV_LOG_ERROR + log_level_offset, 96 "broken stream, invalid padding\n"); 97 return AVERROR_INVALIDDATA; 98 } 99 100 /* sample or frame count */ 101 fi->frame_or_sample_num = get_utf8(gb); 102 if (fi->frame_or_sample_num < 0) { 103 av_log(logctx, AV_LOG_ERROR + log_level_offset, 104 "sample/frame number invalid; utf8 fscked\n"); 105 return AVERROR_INVALIDDATA; 106 } 107 108 /* blocksize */ 109 if (bs_code == 0) { 110 av_log(logctx, AV_LOG_ERROR + log_level_offset, 111 "reserved blocksize code: 0\n"); 112 return AVERROR_INVALIDDATA; 113 } else if (bs_code == 6) { 114 fi->blocksize = get_bits(gb, 8) + 1; 115 } else if (bs_code == 7) { 116 fi->blocksize = get_bits(gb, 16) + 1; 117 } else { 118 fi->blocksize = ff_flac_blocksize_table[bs_code]; 119 } 120 121 /* sample rate */ 122 if (sr_code < 12) { 123 fi->samplerate = ff_flac_sample_rate_table[sr_code]; 124 } else if (sr_code == 12) { 125 fi->samplerate = get_bits(gb, 8) * 1000; 126 } else if (sr_code == 13) { 127 fi->samplerate = get_bits(gb, 16); 128 } else if (sr_code == 14) { 129 fi->samplerate = get_bits(gb, 16) * 10; 130 } else { 131 av_log(logctx, AV_LOG_ERROR + log_level_offset, 132 "illegal sample rate code %d\n", 133 sr_code); 134 return AVERROR_INVALIDDATA; 135 } 136 137 /* header CRC-8 check */ 138 skip_bits(gb, 8); 139 if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer, 140 get_bits_count(gb)/8)) { 141 av_log(logctx, AV_LOG_ERROR + log_level_offset, 142 "header crc mismatch\n"); 143 return AVERROR_INVALIDDATA; 144 } 145 146 return 0; 147 } 148 149 int ff_flac_is_extradata_valid(AVCodecContext *avctx, 150 uint8_t **streaminfo_start) 151 { 152 if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) { 153 av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n"); 154 return 0; 155 } 156 if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) { 157 /* extradata contains STREAMINFO only */ 158 if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) { 159 av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n", 160 FLAC_STREAMINFO_SIZE-avctx->extradata_size); 161 } 162 *streaminfo_start = avctx->extradata; 163 } else { 164 if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) { 165 av_log(avctx, AV_LOG_ERROR, "extradata too small.\n"); 166 return 0; 167 } 168 *streaminfo_start = &avctx->extradata[8]; 169 } 170 return 1; 171 } 172 173 void ff_flac_set_channel_layout(AVCodecContext *avctx, int channels) 174 { 175 if (channels == avctx->ch_layout.nb_channels && 176 avctx->ch_layout.order != AV_CHANNEL_ORDER_UNSPEC) 177 return; 178 179 av_channel_layout_uninit(&avctx->ch_layout); 180 if (channels <= FF_ARRAY_ELEMS(flac_channel_layouts)) 181 avctx->ch_layout = flac_channel_layouts[channels - 1]; 182 else 183 avctx->ch_layout = (AVChannelLayout){ .order = AV_CHANNEL_ORDER_UNSPEC, 184 .nb_channels = channels }; 185 } 186 187 int ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s, 188 const uint8_t *buffer) 189 { 190 GetBitContext gb; 191 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8); 192 193 skip_bits(&gb, 16); /* skip min blocksize */ 194 s->max_blocksize = get_bits(&gb, 16); 195 if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) { 196 av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n", 197 s->max_blocksize); 198 s->max_blocksize = 16; 199 return AVERROR_INVALIDDATA; 200 } 201 202 skip_bits(&gb, 24); /* skip min frame size */ 203 s->max_framesize = get_bits(&gb, 24); 204 205 s->samplerate = get_bits(&gb, 20); 206 s->channels = get_bits(&gb, 3) + 1; 207 s->bps = get_bits(&gb, 5) + 1; 208 209 if (s->bps < 4) { 210 av_log(avctx, AV_LOG_ERROR, "invalid bps: %d\n", s->bps); 211 s->bps = 16; 212 return AVERROR_INVALIDDATA; 213 } 214 215 avctx->sample_rate = s->samplerate; 216 avctx->bits_per_raw_sample = s->bps; 217 ff_flac_set_channel_layout(avctx, s->channels); 218 219 s->samples = get_bits64(&gb, 36); 220 221 skip_bits_long(&gb, 64); /* md5 sum */ 222 skip_bits_long(&gb, 64); /* md5 sum */ 223 224 return 0; 225 }