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tak.c
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1 /*
2  * TAK common code
3  * Copyright (c) 2012 Paul B Mahol
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/bswap.h"
23 #include "libavutil/crc.h"
24 #include "libavutil/intreadwrite.h"
25 #include "tak.h"
26 
27 static const int64_t tak_channel_layouts[] = {
28  0,
47 };
48 
49 static const uint16_t frame_duration_type_quants[] = {
50  3, 4, 6, 8, 4096, 8192, 16384, 512, 1024, 2048,
51 };
52 
54 {
55  int nb_samples, max_nb_samples;
56 
57  if (type <= TAK_FST_250ms) {
58  nb_samples = sample_rate * frame_duration_type_quants[type] >>
60  max_nb_samples = 16384;
61  } else if (type < FF_ARRAY_ELEMS(frame_duration_type_quants)) {
62  nb_samples = frame_duration_type_quants[type];
63  max_nb_samples = sample_rate *
66  } else {
67  return AVERROR_INVALIDDATA;
68  }
69 
70  if (nb_samples <= 0 || nb_samples > max_nb_samples)
71  return AVERROR_INVALIDDATA;
72 
73  return nb_samples;
74 }
75 
76 static int crc_init = 0;
77 #if CONFIG_SMALL
78 #define CRC_TABLE_SIZE 257
79 #else
80 #define CRC_TABLE_SIZE 1024
81 #endif
83 
85 {
86  if (!crc_init) {
87  av_crc_init(crc_24, 0, 24, 0x864CFBU, sizeof(crc_24));
88  crc_init = 1;
89  }
90 }
91 
92 int ff_tak_check_crc(const uint8_t *buf, unsigned int buf_size)
93 {
94  uint32_t crc, CRC;
95 
96  if (buf_size < 4)
97  return AVERROR_INVALIDDATA;
98  buf_size -= 3;
99 
100  CRC = av_bswap32(AV_RL24(buf + buf_size)) >> 8;
101  crc = av_crc(crc_24, 0xCE04B7U, buf, buf_size);
102  if (CRC != crc)
103  return AVERROR_INVALIDDATA;
104 
105  return 0;
106 }
107 
109 {
110  uint64_t channel_mask = 0;
111  int frame_type, i;
112 
115 
116  frame_type = get_bits(gb, TAK_SIZE_FRAME_DURATION_BITS);
118 
122  s->bps = get_bits(gb, TAK_FORMAT_BPS_BITS) +
123  TAK_BPS_MIN;
126 
127  if (get_bits1(gb)) {
129  if (get_bits1(gb)) {
130  for (i = 0; i < s->channels; i++) {
132 
133  if (value < FF_ARRAY_ELEMS(tak_channel_layouts))
134  channel_mask |= tak_channel_layouts[value];
135  }
136  }
137  }
138 
139  s->ch_layout = channel_mask;
140  s->frame_samples = tak_get_nb_samples(s->sample_rate, frame_type);
141 }
142 
144  TAKStreamInfo *ti, int log_level_offset)
145 {
147  av_log(avctx, AV_LOG_ERROR + log_level_offset, "missing sync id\n");
148  return AVERROR_INVALIDDATA;
149  }
150 
153 
154  if (ti->flags & TAK_FRAME_FLAG_IS_LAST) {
156  skip_bits(gb, 2);
157  } else {
158  ti->last_frame_samples = 0;
159  }
160 
161  if (ti->flags & TAK_FRAME_FLAG_HAS_INFO) {
163 
164  if (get_bits(gb, 6))
165  skip_bits(gb, 25);
166  align_get_bits(gb);
167  }
168 
170  return AVERROR_INVALIDDATA;
171 
172  skip_bits(gb, 24);
173 
174  return 0;
175 }