Directory: | ../../../ffmpeg/ |
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File: | src/libavcodec/ac3_parser.c |
Date: | 2022-07-04 19:11:22 |
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Lines: | 111 | 117 | 94.9% |
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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 |