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
  26 #define BITSTREAM_READER_LE
  27 #include "bitstream.h"
  28 #include "tak.h"
  29
  30 static const uint16_t frame_duration_type_quants[] = {
  31     3, 4, 6, 8, 4096, 8192, 16384, 512, 1024, 2048,
  32 };
  33
  34 static int tak_get_nb_samples(int sample_rate, enum TAKFrameSizeType type)
  35 {
  36     int nb_samples, max_nb_samples;
  37
  38     if (type <= TAK_FST_250ms) {
  39         nb_samples     = sample_rate * frame_duration_type_quants[type] >>
  40                          TAK_FRAME_DURATION_QUANT_SHIFT;
  41         max_nb_samples = 16384;
  42     } else if (type < FF_ARRAY_ELEMS(frame_duration_type_quants)) {
  43         nb_samples     = frame_duration_type_quants[type];
  44         max_nb_samples = sample_rate *
  45                          frame_duration_type_quants[TAK_FST_250ms] >>
  46                          TAK_FRAME_DURATION_QUANT_SHIFT;
  47     } else {
  48         return AVERROR_INVALIDDATA;
  49     }
  50
  51     if (nb_samples <= 0 || nb_samples > max_nb_samples)
  52         return AVERROR_INVALIDDATA;
  53
  54     return nb_samples;
  55 }
  56
  57 static int crc_init = 0;
  58 #if CONFIG_SMALL
  59 #define CRC_TABLE_SIZE 257
  60 #else
  61 #define CRC_TABLE_SIZE 1024
  62 #endif
  63 static AVCRC crc_24[CRC_TABLE_SIZE];
  64
  65 av_cold void ff_tak_init_crc(void)
  66 {
  67     if (!crc_init) {
  68         av_crc_init(crc_24, 0, 24, 0x864CFBU, sizeof(crc_24));
  69         crc_init = 1;
  70     }
  71 }
  72
  73 int ff_tak_check_crc(const uint8_t *buf, unsigned int buf_size)
  74 {
  75     uint32_t crc, CRC;
  76
  77     if (buf_size < 4)
  78         return AVERROR_INVALIDDATA;
  79     buf_size -= 3;
  80
  81     CRC = av_bswap32(AV_RL24(buf + buf_size)) >> 8;
  82     crc = av_crc(crc_24, 0xCE04B7U, buf, buf_size);
  83     if (CRC != crc)
  84         return AVERROR_INVALIDDATA;
  85
  86     return 0;
  87 }
  88
  89 void avpriv_tak_parse_streaminfo(BitstreamContext *bc, TAKStreamInfo *s)
  90 {
  91     uint64_t channel_mask = 0;
  92     int frame_type, i;
  93
  94     s->codec = bitstream_read(bc, TAK_ENCODER_CODEC_BITS);
  95     bitstream_skip(bc, TAK_ENCODER_PROFILE_BITS);
  96
  97     frame_type = bitstream_read(bc, TAK_SIZE_FRAME_DURATION_BITS);
  98     s->samples = bitstream_read_63(bc, TAK_SIZE_SAMPLES_NUM_BITS);
  99
 100     s->data_type   = bitstream_read(bc, TAK_FORMAT_DATA_TYPE_BITS);
 101     s->sample_rate = bitstream_read(bc, TAK_FORMAT_SAMPLE_RATE_BITS) +
 102                      TAK_SAMPLE_RATE_MIN;
 103     s->bps         = bitstream_read(bc, TAK_FORMAT_BPS_BITS) +
 104                      TAK_BPS_MIN;
 105     s->channels    = bitstream_read(bc, TAK_FORMAT_CHANNEL_BITS) +
 106                      TAK_CHANNELS_MIN;
 107
 108     if (bitstream_read_bit(bc)) {
 109         bitstream_skip(bc, TAK_FORMAT_VALID_BITS);
 110         if (bitstream_read_bit(bc)) {
 111             for (i = 0; i < s->channels; i++) {
 112                 int value = bitstream_read(bc, TAK_FORMAT_CH_LAYOUT_BITS);
 113
 114                 if (value > 0 && value <= 18)
 115                     channel_mask |= 1 << (value - 1);
 116             }
 117         }
 118     }
 119
 120     s->ch_layout     = channel_mask;
 121     s->frame_samples = tak_get_nb_samples(s->sample_rate, frame_type);
 122 }
 123
 124 int ff_tak_decode_frame_header(AVCodecContext *avctx, BitstreamContext *bc,
 125                                TAKStreamInfo *ti, int log_level_offset)
 126 {
 127     if (bitstream_read(bc, TAK_FRAME_HEADER_SYNC_ID_BITS) != TAK_FRAME_HEADER_SYNC_ID) {
 128         av_log(avctx, AV_LOG_ERROR + log_level_offset, "missing sync id\n");
 129         return AVERROR_INVALIDDATA;
 130     }
 131
 132     ti->flags     = bitstream_read(bc, TAK_FRAME_HEADER_FLAGS_BITS);
 133     ti->frame_num = bitstream_read(bc, TAK_FRAME_HEADER_NO_BITS);
 134
 135     if (ti->flags & TAK_FRAME_FLAG_IS_LAST) {
 136         ti->last_frame_samples = bitstream_read(bc, TAK_FRAME_HEADER_SAMPLE_COUNT_BITS) + 1;
 137         bitstream_skip(bc, 2);
 138     } else {
 139         ti->last_frame_samples = 0;
 140     }
 141
 142     if (ti->flags & TAK_FRAME_FLAG_HAS_INFO) {
 143         avpriv_tak_parse_streaminfo(bc, ti);
 144
 145         if (bitstream_read(bc, 6))
 146             bitstream_skip(bc, 25);
 147         bitstream_align(bc);
 148     }
 149
 150     bitstream_skip(bc, 24);
 151
 152     return 0;
 153 }