FFmpeg  4.4.4
aac_ac3_parser.c
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1 /*
2  * Common AAC and 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 
24 #include "libavutil/common.h"
25 #include "parser.h"
26 #include "aac_ac3_parser.h"
27 
29  AVCodecContext *avctx,
30  const uint8_t **poutbuf, int *poutbuf_size,
31  const uint8_t *buf, int buf_size)
32 {
33  AACAC3ParseContext *s = s1->priv_data;
34  ParseContext *pc = &s->pc;
35  int len, i;
36  int new_frame_start;
37  int got_frame = 0;
38 
39 get_next:
41  if(s->remaining_size <= buf_size){
42  if(s->remaining_size && !s->need_next_header){
43  i= s->remaining_size;
44  s->remaining_size = 0;
45  }else{ //we need a header first
46  len=0;
47  for(i=s->remaining_size; i<buf_size; i++){
48  s->state = (s->state<<8) + buf[i];
49  if((len=s->sync(s->state, s, &s->need_next_header, &new_frame_start)))
50  break;
51  }
52  if(len<=0){
54  }else{
55  got_frame = 1;
56  s->state=0;
57  i-= s->header_size -1;
58  s->remaining_size = len;
59  if(!new_frame_start || pc->index+i<=0){
60  s->remaining_size += i;
61  goto get_next;
62  }
63  else if (i < 0) {
64  s->remaining_size += i;
65  }
66  }
67  }
68  }
69 
70  if(ff_combine_frame(pc, i, &buf, &buf_size)<0){
71  s->remaining_size -= FFMIN(s->remaining_size, buf_size);
72  *poutbuf = NULL;
73  *poutbuf_size = 0;
74  return buf_size;
75  }
76 
77  *poutbuf = buf;
78  *poutbuf_size = buf_size;
79 
80  /* update codec info */
81  if(s->codec_id)
82  avctx->codec_id = s->codec_id;
83 
84  if (got_frame) {
85  /* Due to backwards compatible HE-AAC the sample rate, channel count,
86  and total number of samples found in an AAC ADTS header are not
87  reliable. Bit rate is still accurate because the total frame
88  duration in seconds is still correct (as is the number of bits in
89  the frame). */
90  if (avctx->codec_id != AV_CODEC_ID_AAC) {
91  avctx->sample_rate = s->sample_rate;
92  if (!CONFIG_EAC3_DECODER || avctx->codec_id != AV_CODEC_ID_EAC3) {
93  avctx->channels = s->channels;
94  avctx->channel_layout = s->channel_layout;
95  }
96  s1->duration = s->samples;
97  avctx->audio_service_type = s->service_type;
98  }
99 
100  /* Calculate the average bit rate */
101  s->frame_number++;
102  if (!CONFIG_EAC3_DECODER || avctx->codec_id != AV_CODEC_ID_EAC3) {
103  avctx->bit_rate +=
104  (s->bit_rate - avctx->bit_rate) / s->frame_number;
105  }
106  }
107 
108  return i;
109 }
int ff_aac_ac3_parse(AVCodecParserContext *s1, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
uint8_t
#define s(width, name)
Definition: cbs_vp9.c:257
audio channel layout utility functions
common internal and external API header
#define FFMIN(a, b)
Definition: common.h:105
#define CONFIG_EAC3_DECODER
Definition: config.h:1057
#define NULL
Definition: coverity.c:32
@ AV_CODEC_ID_EAC3
Definition: codec_id.h:464
@ AV_CODEC_ID_AAC
Definition: codec_id.h:426
int i
Definition: input.c:407
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:238
#define END_NOT_FOUND
Definition: parser.h:40
#define s1
Definition: regdef.h:38
main external API structure.
Definition: avcodec.h:536
enum AVAudioServiceType audio_service_type
Type of service that the audio stream conveys.
Definition: avcodec.h:1261
int64_t bit_rate
the average bitrate
Definition: avcodec.h:586
int sample_rate
samples per second
Definition: avcodec.h:1196
int channels
number of audio channels
Definition: avcodec.h:1197
enum AVCodecID codec_id
Definition: avcodec.h:546
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1247
int index
Definition: parser.h:30
int len