3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2003 Michael Niedermayer
6 * This file is part of FFmpeg.
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.
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.
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
25 #include "libavutil/channel_layout.h"
27 #include "ac3_parser.h"
28 #include "ac3_parser_internal.h"
29 #include "aac_ac3_parser.h"
33 #define AC3_HEADER_SIZE 7
37 static const uint8_t eac3_blocks[4] = {
42 * Table for center mix levels
43 * reference: Section 5.4.2.4 cmixlev
45 static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
48 * Table for surround mix levels
49 * reference: Section 5.4.2.5 surmixlev
51 static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
54 int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr)
58 memset(hdr, 0, sizeof(*hdr));
60 hdr->sync_word = get_bits(gbc, 16);
61 if(hdr->sync_word != 0x0B77)
62 return AAC_AC3_PARSE_ERROR_SYNC;
64 /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
65 hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
66 if(hdr->bitstream_id > 16)
67 return AAC_AC3_PARSE_ERROR_BSID;
71 /* set default mix levels */
72 hdr->center_mix_level = 5; // -4.5dB
73 hdr->surround_mix_level = 6; // -6.0dB
75 /* set default dolby surround mode */
76 hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED;
78 if(hdr->bitstream_id <= 10) {
80 hdr->crc1 = get_bits(gbc, 16);
81 hdr->sr_code = get_bits(gbc, 2);
83 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
85 frame_size_code = get_bits(gbc, 6);
86 if(frame_size_code > 37)
87 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
89 skip_bits(gbc, 5); // skip bsid, already got it
91 hdr->bitstream_mode = get_bits(gbc, 3);
92 hdr->channel_mode = get_bits(gbc, 3);
94 if(hdr->channel_mode == AC3_CHMODE_STEREO) {
95 hdr->dolby_surround_mode = get_bits(gbc, 2);
97 if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
98 hdr-> center_mix_level = center_levels[get_bits(gbc, 2)];
99 if(hdr->channel_mode & 4)
100 hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
102 hdr->lfe_on = get_bits1(gbc);
104 hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
105 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
106 hdr->bit_rate = (ff_ac3_bitrate_tab[frame_size_code>>1] * 1000) >> hdr->sr_shift;
107 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
108 hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2;
109 hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT;
110 hdr->substreamid = 0;
114 hdr->frame_type = get_bits(gbc, 2);
115 if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
116 return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
118 hdr->substreamid = get_bits(gbc, 3);
120 hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
121 if(hdr->frame_size < AC3_HEADER_SIZE)
122 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
124 hdr->sr_code = get_bits(gbc, 2);
125 if (hdr->sr_code == 3) {
126 int sr_code2 = get_bits(gbc, 2);
128 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
129 hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
132 hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)];
133 hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
137 hdr->channel_mode = get_bits(gbc, 3);
138 hdr->lfe_on = get_bits1(gbc);
140 hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate /
141 (hdr->num_blocks * 256);
142 hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
144 hdr->channel_layout = avpriv_ac3_channel_layout_tab[hdr->channel_mode];
146 hdr->channel_layout |= AV_CH_LOW_FREQUENCY;
151 // TODO: Better way to pass AC3HeaderInfo fields to mov muxer.
152 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
160 *phdr = av_mallocz(sizeof(AC3HeaderInfo));
162 return AVERROR(ENOMEM);
165 init_get_bits8(&gb, buf, size);
166 err = ff_ac3_parse_header(&gb, hdr);
168 return AVERROR_INVALIDDATA;
170 return get_bits_count(&gb);
173 int av_ac3_parse_header(const uint8_t *buf, size_t size,
174 uint8_t *bitstream_id, uint16_t *frame_size)
180 init_get_bits8(&gb, buf, size);
181 err = ff_ac3_parse_header(&gb, &hdr);
183 return AVERROR_INVALIDDATA;
185 *bitstream_id = hdr.bitstream_id;
186 *frame_size = hdr.frame_size;
191 static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
192 int *need_next_header, int *new_frame_start)
197 uint8_t u8[8 + AV_INPUT_BUFFER_PADDING_SIZE];
198 } tmp = { av_be2ne64(state) };
202 init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54);
203 err = ff_ac3_parse_header(&gbc, &hdr);
208 hdr_info->sample_rate = hdr.sample_rate;
209 hdr_info->bit_rate = hdr.bit_rate;
210 hdr_info->channels = hdr.channels;
211 hdr_info->channel_layout = hdr.channel_layout;
212 hdr_info->samples = hdr.num_blocks * 256;
213 hdr_info->service_type = hdr.bitstream_mode;
214 if (hdr.bitstream_mode == 0x7 && hdr.channels > 1)
215 hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
216 if(hdr.bitstream_id>10)
217 hdr_info->codec_id = AV_CODEC_ID_EAC3;
218 else if (hdr_info->codec_id == AV_CODEC_ID_NONE)
219 hdr_info->codec_id = AV_CODEC_ID_AC3;
221 *need_next_header = (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT);
222 *new_frame_start = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT);
223 return hdr.frame_size;
226 static av_cold int ac3_parse_init(AVCodecParserContext *s1)
228 AACAC3ParseContext *s = s1->priv_data;
229 s->header_size = AC3_HEADER_SIZE;
235 AVCodecParser ff_ac3_parser = {
236 .codec_ids = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 },
237 .priv_data_size = sizeof(AACAC3ParseContext),
238 .parser_init = ac3_parse_init,
239 .parser_parse = ff_aac_ac3_parse,
240 .parser_close = ff_parse_close,
245 int avpriv_ac3_parse_header(AC3HeaderInfo **phdr, const uint8_t *buf,
248 return AVERROR(ENOSYS);
251 int av_ac3_parse_header(const uint8_t *buf, size_t size,
252 uint8_t *bitstream_id, uint16_t *frame_size)
254 return AVERROR(ENOSYS);