FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/ac3_parser.c
Date: 2022-07-04 19:11:22
Exec Total Coverage
Lines: 111 117 94.9%
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 #include "config_components.h"
25
26 #include "libavutil/channel_layout.h"
27 #include "parser.h"
28 #include "ac3defs.h"
29 #include "ac3tab.h"
30 #include "ac3_parser.h"
31 #include "ac3_parser_internal.h"
32 #include "aac_ac3_parser.h"
33 #include "get_bits.h"
34
35
36 #define AC3_HEADER_SIZE 7
37
38 #if CONFIG_AC3_PARSER
39
40 static const uint8_t eac3_blocks[4] = {
41 1, 2, 3, 6
42 };
43
44 /**
45 * Table for center mix levels
46 * reference: Section 5.4.2.4 cmixlev
47 */
48 static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
49
50 /**
51 * Table for surround mix levels
52 * reference: Section 5.4.2.5 surmixlev
53 */
54 static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
55
56
57 60560 int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
58 {
59 int frame_size_code;
60
61 60560 memset(hdr, 0, sizeof(*hdr));
62
63 60560 hdr->sync_word = get_bits(gbc, 16);
64
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60560 if(hdr->sync_word != 0x0B77)
65 41131 return AAC_AC3_PARSE_ERROR_SYNC;
66
67 /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
68 19429 hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
69
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19429 if(hdr->bitstream_id > 16)
70 2868 return AAC_AC3_PARSE_ERROR_BSID;
71
72 16561 hdr->num_blocks = 6;
73 16561 hdr->ac3_bit_rate_code = -1;
74
75 /* set default mix levels */
76 16561 hdr->center_mix_level = 5; // -4.5dB
77 16561 hdr->surround_mix_level = 6; // -6.0dB
78
79 /* set default dolby surround mode */
80 16561 hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED;
81
82
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16561 if(hdr->bitstream_id <= 10) {
83 /* Normal AC-3 */
84 8413 hdr->crc1 = get_bits(gbc, 16);
85 8413 hdr->sr_code = get_bits(gbc, 2);
86
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8413 if(hdr->sr_code == 3)
87 174 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
88
89 8239 frame_size_code = get_bits(gbc, 6);
90
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8239 if(frame_size_code > 37)
91 198 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
92
93 8041 hdr->ac3_bit_rate_code = (frame_size_code >> 1);
94
95 8041 skip_bits(gbc, 5); // skip bsid, already got it
96
97 8041 hdr->bitstream_mode = get_bits(gbc, 3);
98 8041 hdr->channel_mode = get_bits(gbc, 3);
99
100
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8041 if(hdr->channel_mode == AC3_CHMODE_STEREO) {
101 1771 hdr->dolby_surround_mode = get_bits(gbc, 2);
102 } else {
103
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6270 if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
104 4629 hdr-> center_mix_level = center_levels[get_bits(gbc, 2)];
105
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6270 if(hdr->channel_mode & 4)
106 4663 hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
107 }
108 8041 hdr->lfe_on = get_bits1(gbc);
109
110 8041 hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
111 8041 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
112 8041 hdr->bit_rate = (ff_ac3_bitrate_tab[hdr->ac3_bit_rate_code] * 1000) >> hdr->sr_shift;
113 8041 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
114 8041 hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2;
115 8041 hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT;
116 8041 hdr->substreamid = 0;
117 } else {
118 /* Enhanced AC-3 */
119 8148 hdr->crc1 = 0;
120 8148 hdr->frame_type = get_bits(gbc, 2);
121
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8148 if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
122 82 return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
123
124 8066 hdr->substreamid = get_bits(gbc, 3);
125
126 8066 hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
127
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8066 if(hdr->frame_size < AC3_HEADER_SIZE)
128 2 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
129
130 8064 hdr->sr_code = get_bits(gbc, 2);
131
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8064 if (hdr->sr_code == 3) {
132 80 int sr_code2 = get_bits(gbc, 2);
133
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80 if(sr_code2 == 3)
134 24 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
135 56 hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
136 56 hdr->sr_shift = 1;
137 } else {
138 7984 hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)];
139 7984 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
140 7984 hdr->sr_shift = 0;
141 }
142
143 8040 hdr->channel_mode = get_bits(gbc, 3);
144 8040 hdr->lfe_on = get_bits1(gbc);
145
146 8040 hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate /
147 8040 (hdr->num_blocks * 256);
148 8040 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
149 }
150 16081 hdr->channel_layout = ff_ac3_channel_layout_tab[hdr->channel_mode];
151
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16081 if (hdr->lfe_on)
152 5763 hdr->channel_layout |= AV_CH_LOW_FREQUENCY;
153
154 16081 return 0;
155 }
156
157 // TODO: Better way to pass AC3HeaderInfo fields to mov muxer.
158 1039 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
159 size_t size)
160 {
161 GetBitContext gb;
162 AC3HeaderInfo *hdr;
163 int err;
164
165
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1039 if (!*phdr)
166 1039 *phdr = av_mallocz(sizeof(AC3HeaderInfo));
167
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1039 if (!*phdr)
168 return AVERROR(ENOMEM);
169 1039 hdr = *phdr;
170
171 1039 err = init_get_bits8(&gb, buf, size);
172
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1039 if (err < 0)
173 return AVERROR_INVALIDDATA;
174 1039 err = ff_ac3_parse_header(&gb, hdr);
175
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1039 if (err < 0)
176 1 return AVERROR_INVALIDDATA;
177
178 1038 return get_bits_count(&gb);
179 }
180
181 24202 int av_ac3_parse_header(const uint8_t *buf, size_t size,
182 uint8_t *bitstream_id, uint16_t *frame_size)
183 {
184 GetBitContext gb;
185 AC3HeaderInfo hdr;
186 int err;
187
188 24202 init_get_bits8(&gb, buf, size);
189 24202 err = ff_ac3_parse_header(&gb, &hdr);
190
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24202 if (err < 0)
191 16446 return AVERROR_INVALIDDATA;
192
193 7756 *bitstream_id = hdr.bitstream_id;
194 7756 *frame_size = hdr.frame_size;
195
196 7756 return 0;
197 }
198
199 32541 static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
200 int *need_next_header, int *new_frame_start)
201 {
202 int err;
203 union {
204 uint64_t u64;
205 uint8_t u8[8 + AV_INPUT_BUFFER_PADDING_SIZE];
206 32541 } tmp = { av_be2ne64(state) };
207 AC3HeaderInfo hdr;
208 GetBitContext gbc;
209
210
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32541 if (tmp.u8[1] == 0x77 && tmp.u8[2] == 0x0b) {
211 FFSWAP(uint8_t, tmp.u8[1], tmp.u8[2]);
212 FFSWAP(uint8_t, tmp.u8[3], tmp.u8[4]);
213 FFSWAP(uint8_t, tmp.u8[5], tmp.u8[6]);
214 }
215
216 32541 init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54);
217 32541 err = ff_ac3_parse_header(&gbc, &hdr);
218
219
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32541 if(err < 0)
220 28032 return 0;
221
222 4509 hdr_info->sample_rate = hdr.sample_rate;
223 4509 hdr_info->bit_rate = hdr.bit_rate;
224 4509 hdr_info->channels = hdr.channels;
225 4509 hdr_info->channel_layout = hdr.channel_layout;
226 4509 hdr_info->samples = hdr.num_blocks * 256;
227 4509 hdr_info->service_type = hdr.bitstream_mode;
228
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4509 if (hdr.bitstream_mode == 0x7 && hdr.channels > 1)
229 hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
230
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4509 if(hdr.bitstream_id>10)
231 2651 hdr_info->codec_id = AV_CODEC_ID_EAC3;
232
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1858 else if (hdr_info->codec_id == AV_CODEC_ID_NONE)
233 58 hdr_info->codec_id = AV_CODEC_ID_AC3;
234
235 4509 *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT);
236
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4509 *need_next_header = *new_frame_start || (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT);
237 4509 return hdr.frame_size;
238 }
239
240 67 static av_cold int ac3_parse_init(AVCodecParserContext *s1)
241 {
242 67 AACAC3ParseContext *s = s1->priv_data;
243 67 s->header_size = AC3_HEADER_SIZE;
244 67 s->sync = ac3_sync;
245 67 return 0;
246 }
247
248
249 const AVCodecParser ff_ac3_parser = {
250 .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 },
251 .priv_data_size = sizeof(AACAC3ParseContext),
252 .parser_init = ac3_parse_init,
253 .parser_parse = ff_aac_ac3_parse,
254 .parser_close = ff_parse_close,
255 };
256
257 #else
258
259 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
260 size_t size)
261 {
262 return AVERROR(ENOSYS);
263 }
264
265 int av_ac3_parse_header(const uint8_t *buf, size_t size,
266 uint8_t *bitstream_id, uint16_t *frame_size)
267 {
268 return AVERROR(ENOSYS);
269 }
270 #endif
271