media/ffvpx/libavcodec/flac.c

   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 }