blob: 83dd90ff676681b218b7ebd9050ee5f8454e716c
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 "libavutil/channel_layout.h" |
24 | #include "parser.h" |
25 | #include "ac3_parser.h" |
26 | #include "aac_ac3_parser.h" |
27 | #include "get_bits.h" |
28 | |
29 | |
30 | #define AC3_HEADER_SIZE 7 |
31 | |
32 | |
33 | static const uint8_t eac3_blocks[4] = { |
34 | 1, 2, 3, 6 |
35 | }; |
36 | |
37 | /** |
38 | * Table for center mix levels |
39 | * reference: Section 5.4.2.4 cmixlev |
40 | */ |
41 | static const uint8_t center_levels[4] = { 4, 5, 6, 5 }; |
42 | |
43 | /** |
44 | * Table for surround mix levels |
45 | * reference: Section 5.4.2.5 surmixlev |
46 | */ |
47 | static const uint8_t surround_levels[4] = { 4, 6, 7, 6 }; |
48 | |
49 | |
50 | int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo **phdr) |
51 | { |
52 | int frame_size_code; |
53 | AC3HeaderInfo *hdr; |
54 | |
55 | if (!*phdr) |
56 | *phdr = av_mallocz(sizeof(AC3HeaderInfo)); |
57 | if (!*phdr) |
58 | return AVERROR(ENOMEM); |
59 | hdr = *phdr; |
60 | |
61 | memset(hdr, 0, sizeof(*hdr)); |
62 | |
63 | hdr->sync_word = get_bits(gbc, 16); |
64 | if(hdr->sync_word != 0x0B77) |
65 | return AAC_AC3_PARSE_ERROR_SYNC; |
66 | |
67 | /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */ |
68 | hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F; |
69 | if(hdr->bitstream_id > 16) |
70 | return AAC_AC3_PARSE_ERROR_BSID; |
71 | |
72 | hdr->num_blocks = 6; |
73 | |
74 | /* set default mix levels */ |
75 | hdr->center_mix_level = 5; // -4.5dB |
76 | hdr->surround_mix_level = 6; // -6.0dB |
77 | |
78 | /* set default dolby surround mode */ |
79 | hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED; |
80 | |
81 | if(hdr->bitstream_id <= 10) { |
82 | /* Normal AC-3 */ |
83 | hdr->crc1 = get_bits(gbc, 16); |
84 | hdr->sr_code = get_bits(gbc, 2); |
85 | if(hdr->sr_code == 3) |
86 | return AAC_AC3_PARSE_ERROR_SAMPLE_RATE; |
87 | |
88 | frame_size_code = get_bits(gbc, 6); |
89 | if(frame_size_code > 37) |
90 | return AAC_AC3_PARSE_ERROR_FRAME_SIZE; |
91 | |
92 | skip_bits(gbc, 5); // skip bsid, already got it |
93 | |
94 | hdr->bitstream_mode = get_bits(gbc, 3); |
95 | hdr->channel_mode = get_bits(gbc, 3); |
96 | |
97 | if(hdr->channel_mode == AC3_CHMODE_STEREO) { |
98 | hdr->dolby_surround_mode = get_bits(gbc, 2); |
99 | } else { |
100 | if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO) |
101 | hdr-> center_mix_level = center_levels[get_bits(gbc, 2)]; |
102 | if(hdr->channel_mode & 4) |
103 | hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)]; |
104 | } |
105 | hdr->lfe_on = get_bits1(gbc); |
106 | |
107 | hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8; |
108 | hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift; |
109 | hdr->bit_rate = (ff_ac3_bitrate_tab[frame_size_code>>1] * 1000) >> hdr->sr_shift; |
110 | hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on; |
111 | hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2; |
112 | hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT; |
113 | hdr->substreamid = 0; |
114 | } else { |
115 | /* Enhanced AC-3 */ |
116 | hdr->crc1 = 0; |
117 | hdr->frame_type = get_bits(gbc, 2); |
118 | if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED) |
119 | return AAC_AC3_PARSE_ERROR_FRAME_TYPE; |
120 | |
121 | hdr->substreamid = get_bits(gbc, 3); |
122 | |
123 | hdr->frame_size = (get_bits(gbc, 11) + 1) << 1; |
124 | if(hdr->frame_size < AC3_HEADER_SIZE) |
125 | return AAC_AC3_PARSE_ERROR_FRAME_SIZE; |
126 | |
127 | hdr->sr_code = get_bits(gbc, 2); |
128 | if (hdr->sr_code == 3) { |
129 | int sr_code2 = get_bits(gbc, 2); |
130 | if(sr_code2 == 3) |
131 | return AAC_AC3_PARSE_ERROR_SAMPLE_RATE; |
132 | hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2; |
133 | hdr->sr_shift = 1; |
134 | } else { |
135 | hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)]; |
136 | hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code]; |
137 | hdr->sr_shift = 0; |
138 | } |
139 | |
140 | hdr->channel_mode = get_bits(gbc, 3); |
141 | hdr->lfe_on = get_bits1(gbc); |
142 | |
143 | hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate / |
144 | (hdr->num_blocks * 256); |
145 | hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on; |
146 | } |
147 | hdr->channel_layout = avpriv_ac3_channel_layout_tab[hdr->channel_mode]; |
148 | if (hdr->lfe_on) |
149 | hdr->channel_layout |= AV_CH_LOW_FREQUENCY; |
150 | |
151 | return 0; |
152 | } |
153 | |
154 | static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info, |
155 | int *need_next_header, int *new_frame_start) |
156 | { |
157 | int err; |
158 | union { |
159 | uint64_t u64; |
160 | uint8_t u8[8 + AV_INPUT_BUFFER_PADDING_SIZE]; |
161 | } tmp = { av_be2ne64(state) }; |
162 | AC3HeaderInfo hdr, *phdr = &hdr; |
163 | GetBitContext gbc; |
164 | |
165 | init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54); |
166 | err = avpriv_ac3_parse_header(&gbc, &phdr); |
167 | |
168 | if(err < 0) |
169 | return 0; |
170 | |
171 | hdr_info->sample_rate = hdr.sample_rate; |
172 | hdr_info->bit_rate = hdr.bit_rate; |
173 | hdr_info->channels = hdr.channels; |
174 | hdr_info->channel_layout = hdr.channel_layout; |
175 | hdr_info->samples = hdr.num_blocks * 256; |
176 | hdr_info->service_type = hdr.bitstream_mode; |
177 | if (hdr.bitstream_mode == 0x7 && hdr.channels > 1) |
178 | hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE; |
179 | if(hdr.bitstream_id>10) |
180 | hdr_info->codec_id = AV_CODEC_ID_EAC3; |
181 | else if (hdr_info->codec_id == AV_CODEC_ID_NONE) |
182 | hdr_info->codec_id = AV_CODEC_ID_AC3; |
183 | |
184 | *need_next_header = (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT); |
185 | *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT); |
186 | return hdr.frame_size; |
187 | } |
188 | |
189 | static av_cold int ac3_parse_init(AVCodecParserContext *s1) |
190 | { |
191 | AACAC3ParseContext *s = s1->priv_data; |
192 | s->header_size = AC3_HEADER_SIZE; |
193 | s->sync = ac3_sync; |
194 | return 0; |
195 | } |
196 | |
197 | |
198 | AVCodecParser ff_ac3_parser = { |
199 | .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 }, |
200 | .priv_data_size = sizeof(AACAC3ParseContext), |
201 | .parser_init = ac3_parse_init, |
202 | .parser_parse = ff_aac_ac3_parse, |
203 | .parser_close = ff_parse_close, |
204 | }; |
205 |