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
23 #include "libavutil/channel_layout.h"
25 #include "ac3_parser.h"
26 #include "aac_ac3_parser.h"
30 #define AC3_HEADER_SIZE 7
33 static const uint8_t eac3_blocks
[4] = {
38 * Table for center mix levels
39 * reference: Section 5.4.2.4 cmixlev
41 static const uint8_t center_levels
[4] = { 4, 5, 6, 5 };
44 * Table for surround mix levels
45 * reference: Section 5.4.2.5 surmixlev
47 static const uint8_t surround_levels
[4] = { 4, 6, 7, 6 };
50 int avpriv_ac3_parse_header2(GetBitContext
*gbc
, AC3HeaderInfo
**phdr
)
56 *phdr
= av_mallocz(sizeof(AC3HeaderInfo
));
58 return AVERROR(ENOMEM
);
61 memset(hdr
, 0, sizeof(*hdr
));
63 hdr
->sync_word
= get_bits(gbc
, 16);
64 if(hdr
->sync_word
!= 0x0B77)
65 return AAC_AC3_PARSE_ERROR_SYNC
;
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
;
74 /* set default mix levels */
75 hdr
->center_mix_level
= 5; // -4.5dB
76 hdr
->surround_mix_level
= 6; // -6.0dB
78 /* set default dolby surround mode */
79 hdr
->dolby_surround_mode
= AC3_DSURMOD_NOTINDICATED
;
81 if(hdr
->bitstream_id
<= 10) {
83 hdr
->crc1
= get_bits(gbc
, 16);
84 hdr
->sr_code
= get_bits(gbc
, 2);
86 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE
;
88 frame_size_code
= get_bits(gbc
, 6);
89 if(frame_size_code
> 37)
90 return AAC_AC3_PARSE_ERROR_FRAME_SIZE
;
92 skip_bits(gbc
, 5); // skip bsid, already got it
94 hdr
->bitstream_mode
= get_bits(gbc
, 3);
95 hdr
->channel_mode
= get_bits(gbc
, 3);
97 if(hdr
->channel_mode
== AC3_CHMODE_STEREO
) {
98 hdr
->dolby_surround_mode
= get_bits(gbc
, 2);
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)];
105 hdr
->lfe_on
= get_bits1(gbc
);
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;
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
;
121 hdr
->substreamid
= get_bits(gbc
, 3);
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
;
127 hdr
->sr_code
= get_bits(gbc
, 2);
128 if (hdr
->sr_code
== 3) {
129 int sr_code2
= get_bits(gbc
, 2);
131 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE
;
132 hdr
->sample_rate
= ff_ac3_sample_rate_tab
[sr_code2
] / 2;
135 hdr
->num_blocks
= eac3_blocks
[get_bits(gbc
, 2)];
136 hdr
->sample_rate
= ff_ac3_sample_rate_tab
[hdr
->sr_code
];
140 hdr
->channel_mode
= get_bits(gbc
, 3);
141 hdr
->lfe_on
= get_bits1(gbc
);
143 hdr
->bit_rate
= (uint32_t)(8.0 * hdr
->frame_size
* hdr
->sample_rate
/
144 (hdr
->num_blocks
* 256.0));
145 hdr
->channels
= ff_ac3_channels_tab
[hdr
->channel_mode
] + hdr
->lfe_on
;
147 hdr
->channel_layout
= avpriv_ac3_channel_layout_tab
[hdr
->channel_mode
];
149 hdr
->channel_layout
|= AV_CH_LOW_FREQUENCY
;
154 int avpriv_ac3_parse_header(GetBitContext
*gbc
, AC3HeaderInfo
*hdr
)
156 AC3HeaderInfo tmp
, *ptmp
= &tmp
;
157 int ret
= avpriv_ac3_parse_header2(gbc
, &ptmp
);
159 memcpy(hdr
, ptmp
, ((intptr_t)&tmp
.channel_layout
) - ((intptr_t)&tmp
) + sizeof(uint64_t));
163 static int ac3_sync(uint64_t state
, AACAC3ParseContext
*hdr_info
,
164 int *need_next_header
, int *new_frame_start
)
169 uint8_t u8
[8 + FF_INPUT_BUFFER_PADDING_SIZE
];
170 } tmp
= { av_be2ne64(state
) };
171 AC3HeaderInfo hdr
, *phdr
= &hdr
;
174 init_get_bits(&gbc
, tmp
.u8
+8-AC3_HEADER_SIZE
, 54);
175 err
= avpriv_ac3_parse_header2(&gbc
, &phdr
);
180 hdr_info
->sample_rate
= hdr
.sample_rate
;
181 hdr_info
->bit_rate
= hdr
.bit_rate
;
182 hdr_info
->channels
= hdr
.channels
;
183 hdr_info
->channel_layout
= hdr
.channel_layout
;
184 hdr_info
->samples
= hdr
.num_blocks
* 256;
185 hdr_info
->service_type
= hdr
.bitstream_mode
;
186 if (hdr
.bitstream_mode
== 0x7 && hdr
.channels
> 1)
187 hdr_info
->service_type
= AV_AUDIO_SERVICE_TYPE_KARAOKE
;
188 if(hdr
.bitstream_id
>10)
189 hdr_info
->codec_id
= AV_CODEC_ID_EAC3
;
190 else if (hdr_info
->codec_id
== AV_CODEC_ID_NONE
)
191 hdr_info
->codec_id
= AV_CODEC_ID_AC3
;
193 *need_next_header
= (hdr
.frame_type
!= EAC3_FRAME_TYPE_AC3_CONVERT
);
194 *new_frame_start
= (hdr
.frame_type
!= EAC3_FRAME_TYPE_DEPENDENT
);
195 return hdr
.frame_size
;
198 static av_cold
int ac3_parse_init(AVCodecParserContext
*s1
)
200 AACAC3ParseContext
*s
= s1
->priv_data
;
201 s
->header_size
= AC3_HEADER_SIZE
;
207 AVCodecParser ff_ac3_parser
= {
208 .codec_ids
= { AV_CODEC_ID_AC3
, AV_CODEC_ID_EAC3
},
209 .priv_data_size
= sizeof(AACAC3ParseContext
),
210 .parser_init
= ac3_parse_init
,
211 .parser_parse
= ff_aac_ac3_parse
,
212 .parser_close
= ff_parse_close
,