libavcodec/tak.c

   1 /*
   2  * TAK common code
   3  * Copyright (c) 2012 Paul B Mahol
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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/bswap.h"
  23 #include "libavutil/crc.h"
  24 #include "libavutil/intreadwrite.h"
  25 #include "tak.h"
  26
  27 static const uint16_t frame_duration_type_quants[] = {
  28     3, 4, 6, 8, 4096, 8192, 16384, 512, 1024, 2048,
  29 };
  30
  31 static int tak_get_nb_samples(int sample_rate, enum TAKFrameSizeType type)
  32 {
  33     int nb_samples, max_nb_samples;
  34
  35     if (type <= TAK_FST_250ms) {
  36         nb_samples     = sample_rate * frame_duration_type_quants[type] >>
  37                          TAK_FRAME_DURATION_QUANT_SHIFT;
  38         max_nb_samples = 16384;
  39     } else if (type < FF_ARRAY_ELEMS(frame_duration_type_quants)) {
  40         nb_samples     = frame_duration_type_quants[type];
  41         max_nb_samples = sample_rate *
  42                          frame_duration_type_quants[TAK_FST_250ms] >>
  43                          TAK_FRAME_DURATION_QUANT_SHIFT;
  44     } else {
  45         return AVERROR_INVALIDDATA;
  46     }
  47
  48     if (nb_samples <= 0 || nb_samples > max_nb_samples)
  49         return AVERROR_INVALIDDATA;
  50
  51     return nb_samples;
  52 }
  53
  54 static int crc_init = 0;
  55 #if CONFIG_SMALL
  56 #define CRC_TABLE_SIZE 257
  57 #else
  58 #define CRC_TABLE_SIZE 1024
  59 #endif
  60 static AVCRC crc_24[CRC_TABLE_SIZE];
  61
  62 av_cold void ff_tak_init_crc(void)
  63 {
  64     if (!crc_init) {
  65         av_crc_init(crc_24, 0, 24, 0x864CFBU, sizeof(crc_24));
  66         crc_init = 1;
  67     }
  68 }
  69
  70 int ff_tak_check_crc(const uint8_t *buf, unsigned int buf_size)
  71 {
  72     uint32_t crc, CRC;
  73
  74     if (buf_size < 4)
  75         return AVERROR_INVALIDDATA;
  76     buf_size -= 3;
  77
  78     CRC = av_bswap32(AV_RL24(buf + buf_size)) >> 8;
  79     crc = av_crc(crc_24, 0xCE04B7U, buf, buf_size);
  80     if (CRC != crc)
  81         return AVERROR_INVALIDDATA;
  82
  83     return 0;
  84 }
  85
  86 void avpriv_tak_parse_streaminfo(GetBitContext *gb, TAKStreamInfo *s)
  87 {
  88     uint64_t channel_mask = 0;
  89     int frame_type, i;
  90
  91     s->codec = get_bits(gb, TAK_ENCODER_CODEC_BITS);
  92     skip_bits(gb, TAK_ENCODER_PROFILE_BITS);
  93
  94     frame_type = get_bits(gb, TAK_SIZE_FRAME_DURATION_BITS);
  95     s->samples = get_bits64(gb, TAK_SIZE_SAMPLES_NUM_BITS);
  96
  97     s->data_type   = get_bits(gb, TAK_FORMAT_DATA_TYPE_BITS);
  98     s->sample_rate = get_bits(gb, TAK_FORMAT_SAMPLE_RATE_BITS) +
  99                      TAK_SAMPLE_RATE_MIN;
 100     s->bps         = get_bits(gb, TAK_FORMAT_BPS_BITS) +
 101                      TAK_BPS_MIN;
 102     s->channels    = get_bits(gb, TAK_FORMAT_CHANNEL_BITS) +
 103                      TAK_CHANNELS_MIN;
 104
 105     if (get_bits1(gb)) {
 106         skip_bits(gb, TAK_FORMAT_VALID_BITS);
 107         if (get_bits1(gb)) {
 108             for (i = 0; i < s->channels; i++) {
 109                 int value = get_bits(gb, TAK_FORMAT_CH_LAYOUT_BITS);
 110
 111                 if (value > 0 && value <= 18)
 112                     channel_mask |= 1 << (value - 1);
 113             }
 114         }
 115     }
 116
 117     s->ch_layout     = channel_mask;
 118     s->frame_samples = tak_get_nb_samples(s->sample_rate, frame_type);
 119 }
 120
 121 int ff_tak_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
 122                                TAKStreamInfo *ti, int log_level_offset)
 123 {
 124     if (get_bits(gb, TAK_FRAME_HEADER_SYNC_ID_BITS) != TAK_FRAME_HEADER_SYNC_ID) {
 125         av_log(avctx, AV_LOG_ERROR + log_level_offset, "missing sync id\n");
 126         return AVERROR_INVALIDDATA;
 127     }
 128
 129     ti->flags     = get_bits(gb, TAK_FRAME_HEADER_FLAGS_BITS);
 130     ti->frame_num = get_bits(gb, TAK_FRAME_HEADER_NO_BITS);
 131
 132     if (ti->flags & TAK_FRAME_FLAG_IS_LAST) {
 133         ti->last_frame_samples = get_bits(gb, TAK_FRAME_HEADER_SAMPLE_COUNT_BITS) + 1;
 134         skip_bits(gb, 2);
 135     } else {
 136         ti->last_frame_samples = 0;
 137     }
 138
 139     if (ti->flags & TAK_FRAME_FLAG_HAS_INFO) {
 140         avpriv_tak_parse_streaminfo(gb, ti);
 141
 142         if (get_bits(gb, 6))
 143             skip_bits(gb, 25);
 144         align_get_bits(gb);
 145     }
 146
 147     skip_bits(gb, 24);
 148
 149     return 0;
 150 }