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
24 #include "mpegaudiodecheader.h"
25 #include "libavutil/common.h"
28 typedef struct MpegAudioParseContext
{
34 } MpegAudioParseContext
;
36 #define MPA_HEADER_SIZE 4
38 /* header + layer + bitrate + freq + lsf/mpeg25 */
39 #define SAME_HEADER_MASK \
40 (0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19))
42 static int mpegaudio_parse(AVCodecParserContext
*s1
,
43 AVCodecContext
*avctx
,
44 const uint8_t **poutbuf
, int *poutbuf_size
,
45 const uint8_t *buf
, int buf_size
)
47 MpegAudioParseContext
*s
= s1
->priv_data
;
48 ParseContext
*pc
= &s
->pc
;
49 uint32_t state
= pc
->state
;
51 int next
= END_NOT_FOUND
;
53 for(i
=0; i
<buf_size
; ){
55 int inc
= FFMIN(buf_size
- i
, s
->frame_size
);
66 int ret
, sr
, channels
, bit_rate
, frame_size
;
67 enum AVCodecID codec_id
;
69 state
= (state
<<8) + buf
[i
++];
71 ret
= avpriv_mpa_decode_header2(state
, &sr
, &channels
, &frame_size
, &bit_rate
, &codec_id
);
76 int header_threshold
= avctx
->codec_id
!= AV_CODEC_ID_NONE
&& avctx
->codec_id
!= codec_id
;
77 if((state
&SAME_HEADER_MASK
) != (s
->header
&SAME_HEADER_MASK
) && s
->header
)
81 s
->frame_size
= ret
-4;
83 if (s
->header_count
> header_threshold
) {
84 avctx
->sample_rate
= sr
;
85 avctx
->channels
= channels
;
86 s1
->duration
= frame_size
;
87 avctx
->codec_id
= codec_id
;
88 if (s
->no_bitrate
|| !avctx
->bit_rate
) {
90 avctx
->bit_rate
+= (bit_rate
- avctx
->bit_rate
) / (s
->header_count
- header_threshold
);
100 if (ff_combine_frame(pc
, next
, &buf
, &buf_size
) < 0) {
107 *poutbuf_size
= buf_size
;
112 AVCodecParser ff_mpegaudio_parser
= {
113 .codec_ids
= { AV_CODEC_ID_MP1
, AV_CODEC_ID_MP2
, AV_CODEC_ID_MP3
},
114 .priv_data_size
= sizeof(MpegAudioParseContext
),
115 .parser_parse
= mpegaudio_parse
,
116 .parser_close
= ff_parse_close
,