FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/ac3_parser.c
Date: 2021-09-26 18:22:30
Exec Total Coverage
Lines: 109 115 94.8%
Branches: 48 56 85.7%

Line Branch Exec Source
1 /*
2 * AC-3 parser
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2003 Michael Niedermayer
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "config.h"
24
25 #include "libavutil/channel_layout.h"
26 #include "parser.h"
27 #include "ac3_parser.h"
28 #include "ac3_parser_internal.h"
29 #include "aac_ac3_parser.h"
30 #include "get_bits.h"
31
32
33 #define AC3_HEADER_SIZE 7
34
35 #if CONFIG_AC3_PARSER
36
37 static const uint8_t eac3_blocks[4] = {
38 1, 2, 3, 6
39 };
40
41 /**
42 * Table for center mix levels
43 * reference: Section 5.4.2.4 cmixlev
44 */
45 static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
46
47 /**
48 * Table for surround mix levels
49 * reference: Section 5.4.2.5 surmixlev
50 */
51 static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
52
53
54 59633 int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
55 {
56 int frame_size_code;
57
58 59633 memset(hdr, 0, sizeof(*hdr));
59
60 59633 hdr->sync_word = get_bits(gbc, 16);
61
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59633 if(hdr->sync_word != 0x0B77)
62 40693 return AAC_AC3_PARSE_ERROR_SYNC;
63
64 /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
65 18940 hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
66
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18940 if(hdr->bitstream_id > 16)
67 2866 return AAC_AC3_PARSE_ERROR_BSID;
68
69 16074 hdr->num_blocks = 6;
70
71 /* set default mix levels */
72 16074 hdr->center_mix_level = 5; // -4.5dB
73 16074 hdr->surround_mix_level = 6; // -6.0dB
74
75 /* set default dolby surround mode */
76 16074 hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED;
77
78
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16074 if(hdr->bitstream_id <= 10) {
79 /* Normal AC-3 */
80 7946 hdr->crc1 = get_bits(gbc, 16);
81 7946 hdr->sr_code = get_bits(gbc, 2);
82
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7946 if(hdr->sr_code == 3)
83 174 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
84
85 7772 frame_size_code = get_bits(gbc, 6);
86
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7772 if(frame_size_code > 37)
87 198 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
88
89 7574 skip_bits(gbc, 5); // skip bsid, already got it
90
91 7574 hdr->bitstream_mode = get_bits(gbc, 3);
92 7574 hdr->channel_mode = get_bits(gbc, 3);
93
94
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7574 if(hdr->channel_mode == AC3_CHMODE_STEREO) {
95 1709 hdr->dolby_surround_mode = get_bits(gbc, 2);
96 } else {
97
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5865 if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
98 4346 hdr-> center_mix_level = center_levels[get_bits(gbc, 2)];
99
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5865 if(hdr->channel_mode & 4)
100 4380 hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
101 }
102 7574 hdr->lfe_on = get_bits1(gbc);
103
104 7574 hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
105 7574 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
106 7574 hdr->bit_rate = (ff_ac3_bitrate_tab[frame_size_code>>1] * 1000) >> hdr->sr_shift;
107 7574 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
108 7574 hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2;
109 7574 hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT;
110 7574 hdr->substreamid = 0;
111 } else {
112 /* Enhanced AC-3 */
113 8128 hdr->crc1 = 0;
114 8128 hdr->frame_type = get_bits(gbc, 2);
115
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8128 if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
116 78 return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
117
118 8050 hdr->substreamid = get_bits(gbc, 3);
119
120 8050 hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
121
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8050 if(hdr->frame_size < AC3_HEADER_SIZE)
122 2 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
123
124 8048 hdr->sr_code = get_bits(gbc, 2);
125
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8048 if (hdr->sr_code == 3) {
126 80 int sr_code2 = get_bits(gbc, 2);
127
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80 if(sr_code2 == 3)
128 24 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
129 56 hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
130 56 hdr->sr_shift = 1;
131 } else {
132 7968 hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)];
133 7968 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
134 7968 hdr->sr_shift = 0;
135 }
136
137 8024 hdr->channel_mode = get_bits(gbc, 3);
138 8024 hdr->lfe_on = get_bits1(gbc);
139
140 8024 hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate /
141 8024 (hdr->num_blocks * 256);
142 8024 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
143 }
144 15598 hdr->channel_layout = avpriv_ac3_channel_layout_tab[hdr->channel_mode];
145
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15598 if (hdr->lfe_on)
146 5470 hdr->channel_layout |= AV_CH_LOW_FREQUENCY;
147
148 15598 return 0;
149 }
150
151 // TODO: Better way to pass AC3HeaderInfo fields to mov muxer.
152 652 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
153 size_t size)
154 {
155 GetBitContext gb;
156 AC3HeaderInfo *hdr;
157 int err;
158
159
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652 if (!*phdr)
160 652 *phdr = av_mallocz(sizeof(AC3HeaderInfo));
161
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652 if (!*phdr)
162 return AVERROR(ENOMEM);
163 652 hdr = *phdr;
164
165 652 err = init_get_bits8(&gb, buf, size);
166
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652 if (err < 0)
167 return AVERROR_INVALIDDATA;
168 652 err = ff_ac3_parse_header(&gb, hdr);
169
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652 if (err < 0)
170 1 return AVERROR_INVALIDDATA;
171
172 651 return get_bits_count(&gb);
173 }
174
175 23994 int av_ac3_parse_header(const uint8_t *buf, size_t size,
176 uint8_t *bitstream_id, uint16_t *frame_size)
177 {
178 GetBitContext gb;
179 AC3HeaderInfo hdr;
180 int err;
181
182 23994 init_get_bits8(&gb, buf, size);
183 23994 err = ff_ac3_parse_header(&gb, &hdr);
184
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23994 if (err < 0)
185 16278 return AVERROR_INVALIDDATA;
186
187 7716 *bitstream_id = hdr.bitstream_id;
188 7716 *frame_size = hdr.frame_size;
189
190 7716 return 0;
191 }
192
193 32219 static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
194 int *need_next_header, int *new_frame_start)
195 {
196 int err;
197 union {
198 uint64_t u64;
199 uint8_t u8[8 + AV_INPUT_BUFFER_PADDING_SIZE];
200 32219 } tmp = { av_be2ne64(state) };
201 AC3HeaderInfo hdr;
202 GetBitContext gbc;
203
204
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32219 if (tmp.u8[1] == 0x77 && tmp.u8[2] == 0x0b) {
205 FFSWAP(uint8_t, tmp.u8[1], tmp.u8[2]);
206 FFSWAP(uint8_t, tmp.u8[3], tmp.u8[4]);
207 FFSWAP(uint8_t, tmp.u8[5], tmp.u8[6]);
208 }
209
210 32219 init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54);
211 32219 err = ff_ac3_parse_header(&gbc, &hdr);
212
213
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32219 if(err < 0)
214 27756 return 0;
215
216 4463 hdr_info->sample_rate = hdr.sample_rate;
217 4463 hdr_info->bit_rate = hdr.bit_rate;
218 4463 hdr_info->channels = hdr.channels;
219 4463 hdr_info->channel_layout = hdr.channel_layout;
220 4463 hdr_info->samples = hdr.num_blocks * 256;
221 4463 hdr_info->service_type = hdr.bitstream_mode;
222
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4463 if (hdr.bitstream_mode == 0x7 && hdr.channels > 1)
223 hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
224
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4463 if(hdr.bitstream_id>10)
225 2651 hdr_info->codec_id = AV_CODEC_ID_EAC3;
226
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1812 else if (hdr_info->codec_id == AV_CODEC_ID_NONE)
227 46 hdr_info->codec_id = AV_CODEC_ID_AC3;
228
229 4463 *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT);
230
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4463 *need_next_header = *new_frame_start || (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT);
231 4463 return hdr.frame_size;
232 }
233
234 55 static av_cold int ac3_parse_init(AVCodecParserContext *s1)
235 {
236 55 AACAC3ParseContext *s = s1->priv_data;
237 55 s->header_size = AC3_HEADER_SIZE;
238 55 s->sync = ac3_sync;
239 55 return 0;
240 }
241
242
243 const AVCodecParser ff_ac3_parser = {
244 .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 },
245 .priv_data_size = sizeof(AACAC3ParseContext),
246 .parser_init = ac3_parse_init,
247 .parser_parse = ff_aac_ac3_parse,
248 .parser_close = ff_parse_close,
249 };
250
251 #else
252
253 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
254 size_t size)
255 {
256 return AVERROR(ENOSYS);
257 }
258
259 int av_ac3_parse_header(const uint8_t *buf, size_t size,
260 uint8_t *bitstream_id, uint16_t *frame_size)
261 {
262 return AVERROR(ENOSYS);
263 }
264 #endif
265