FFmpeg
aacdec.c
Go to the documentation of this file.
1 /*
2  * raw ADTS AAC demuxer
3  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4  * Copyright (c) 2009 Robert Swain ( rob opendot cl )
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/avassert.h"
24 #include "libavutil/intreadwrite.h"
25 #include "avformat.h"
26 #include "avio_internal.h"
27 #include "internal.h"
28 #include "id3v1.h"
29 #include "id3v2.h"
30 #include "apetag.h"
31 
32 #define ADTS_HEADER_SIZE 7
33 
34 static int adts_aac_probe(const AVProbeData *p)
35 {
36  int max_frames = 0, first_frames = 0;
37  int fsize, frames;
38  const uint8_t *buf0 = p->buf;
39  const uint8_t *buf2;
40  const uint8_t *buf;
41  const uint8_t *end = buf0 + p->buf_size - 7;
42 
43  buf = buf0;
44 
45  for (; buf < end; buf = buf2 + 1) {
46  buf2 = buf;
47 
48  for (frames = 0; buf2 < end; frames++) {
49  uint32_t header = AV_RB16(buf2);
50  if ((header & 0xFFF6) != 0xFFF0) {
51  if (buf != buf0) {
52  // Found something that isn't an ADTS header, starting
53  // from a position other than the start of the buffer.
54  // Discard the count we've accumulated so far since it
55  // probably was a false positive.
56  frames = 0;
57  }
58  break;
59  }
60  fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF;
61  if (fsize < 7)
62  break;
63  fsize = FFMIN(fsize, end - buf2);
64  buf2 += fsize;
65  }
66  max_frames = FFMAX(max_frames, frames);
67  if (buf == buf0)
68  first_frames = frames;
69  }
70 
71  if (first_frames >= 3)
72  return AVPROBE_SCORE_EXTENSION + 1;
73  else if (max_frames > 100)
75  else if (max_frames >= 3)
76  return AVPROBE_SCORE_EXTENSION / 2;
77  else if (first_frames >= 1)
78  return 1;
79  else
80  return 0;
81 }
82 
84 {
85  uint16_t state;
86 
87  // skip data until an ADTS frame is found
88  state = avio_r8(s->pb);
89  while (!avio_feof(s->pb) && avio_tell(s->pb) < s->probesize) {
90  state = (state << 8) | avio_r8(s->pb);
91  if ((state >> 4) != 0xFFF)
92  continue;
93  avio_seek(s->pb, -2, SEEK_CUR);
94  break;
95  }
96  if (s->pb->eof_reached)
97  return AVERROR_EOF;
98  if ((state >> 4) != 0xFFF)
99  return AVERROR_INVALIDDATA;
100 
101  return 0;
102 }
103 
105 {
106  AVStream *st;
107  int ret;
108 
109  st = avformat_new_stream(s, NULL);
110  if (!st)
111  return AVERROR(ENOMEM);
112 
116 
117  ff_id3v1_read(s);
118  if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
120  int64_t cur = avio_tell(s->pb);
121  ff_ape_parse_tag(s);
122  avio_seek(s->pb, cur, SEEK_SET);
123  }
124 
125  ret = adts_aac_resync(s);
126  if (ret < 0)
127  return ret;
128 
129  // LCM of all possible ADTS sample rates
130  avpriv_set_pts_info(st, 64, 1, 28224000);
131 
132  return 0;
133 }
134 
136 {
137  AVDictionary *metadata = NULL;
138  AVIOContext ioctx;
139  ID3v2ExtraMeta *id3v2_extra_meta = NULL;
140  int ret;
141 
142  ret = av_append_packet(s->pb, pkt, ff_id3v2_tag_len(pkt->data) - pkt->size);
143  if (ret < 0) {
144  return ret;
145  }
146 
147  ffio_init_context(&ioctx, pkt->data, pkt->size, 0, NULL, NULL, NULL, NULL);
148  ff_id3v2_read_dict(&ioctx, &metadata, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);
149  if ((ret = ff_id3v2_parse_priv_dict(&metadata, id3v2_extra_meta)) < 0)
150  goto error;
151 
152  if (metadata) {
153  if ((ret = av_dict_copy(&s->metadata, metadata, 0)) < 0)
154  goto error;
156  }
157 
158 error:
159  av_packet_unref(pkt);
160  ff_id3v2_free_extra_meta(&id3v2_extra_meta);
161  av_dict_free(&metadata);
162 
163  return ret;
164 }
165 
167 {
168  int ret, fsize;
169 
170 retry:
171  ret = av_get_packet(s->pb, pkt, ADTS_HEADER_SIZE);
172  if (ret < 0)
173  return ret;
174 
175  if (ret < ADTS_HEADER_SIZE) {
176  return AVERROR(EIO);
177  }
178 
179  if ((AV_RB16(pkt->data) >> 4) != 0xfff) {
180  // Parse all the ID3 headers between frames
182 
183  av_assert2(append > 0);
184  ret = av_append_packet(s->pb, pkt, append);
185  if (ret != append) {
186  return AVERROR(EIO);
187  }
189  av_packet_unref(pkt);
190  ret = adts_aac_resync(s);
191  } else
192  ret = handle_id3(s, pkt);
193  if (ret < 0)
194  return ret;
195 
196  goto retry;
197  }
198 
199  fsize = (AV_RB32(pkt->data + 3) >> 13) & 0x1FFF;
200  if (fsize < ADTS_HEADER_SIZE) {
201  return AVERROR_INVALIDDATA;
202  }
203 
204  ret = av_append_packet(s->pb, pkt, fsize - pkt->size);
205 
206  return ret;
207 }
208 
210  .name = "aac",
211  .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"),
212  .read_probe = adts_aac_probe,
213  .read_header = adts_aac_read_header,
214  .read_packet = adts_aac_read_packet,
215  .flags = AVFMT_GENERIC_INDEX,
216  .extensions = "aac",
217  .mime_type = "audio/aac,audio/aacp,audio/x-aac",
218  .raw_codec_id = AV_CODEC_ID_AAC,
219 };
int64_t probesize
Maximum size of the data read from input for determining the input container format.
Definition: avformat.h:1405
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4871
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:279
int size
Definition: packet.h:364
#define ID3v2_DEFAULT_MAGIC
Default magic bytes for ID3v2 header: "ID3".
Definition: id3v2.h:35
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
int event_flags
Flags indicating events happening on the file, a combination of AVFMT_EVENT_FLAG_*.
Definition: avformat.h:1560
int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:217
static AVPacket pkt
static void error(const char *err)
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:91
if it could not because there are no more frames
static int adts_aac_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: aacdec.c:166
Format I/O context.
Definition: avformat.h:1239
#define ID3v2_HEADER_SIZE
Definition: id3v2.h:30
uint8_t
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
static int adts_aac_read_header(AVFormatContext *s)
Definition: aacdec.c:104
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:92
enum AVStreamParseType need_parsing
Definition: avformat.h:1088
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4453
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:91
static uint8_t * append(uint8_t *buf, const uint8_t *src, int size)
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
uint8_t * data
Definition: packet.h:363
#define AVERROR_EOF
End of file.
Definition: error.h:55
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:305
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const uint8_t header[24]
Definition: sdr2.c:67
full parsing and repack with timestamp and position generation by parser for raw this assumes that ea...
Definition: avformat.h:803
int av_append_packet(AVIOContext *s, AVPacket *pkt, int size)
Read data and append it to the current content of the AVPacket.
Definition: utils.c:315
#define ADTS_HEADER_SIZE
Definition: aacdec.c:32
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1479
AVInputFormat ff_aac_demuxer
Definition: aacdec.c:209
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
ff_const59 struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1251
void av_dict_free(AVDictionary **pm)
Free all the memory allocated for an AVDictionary struct and all keys and values. ...
Definition: dict.c:203
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
void ff_id3v2_free_extra_meta(ID3v2ExtraMeta **extra_meta)
Free memory allocated parsing special (non-text) metadata.
Definition: id3v2.c:1114
simple assert() macros that are a bit more flexible than ISO C assert().
static int adts_aac_probe(const AVProbeData *p)
Definition: aacdec.c:34
#define FFMAX(a, b)
Definition: common.h:94
int64_t ff_ape_parse_tag(AVFormatContext *s)
Read and parse an APE tag.
Definition: apetag.c:118
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:628
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
#define FFMIN(a, b)
Definition: common.h:96
#define AVFMT_EVENT_FLAG_METADATA_UPDATED
Definition: avformat.h:1567
#define s(width, name)
Definition: cbs_vp9.c:257
Stream structure.
Definition: avformat.h:880
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
AVIOContext * pb
I/O context.
Definition: avformat.h:1281
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:606
int ff_id3v2_parse_priv_dict(AVDictionary **metadata, ID3v2ExtraMeta *extra_meta)
Parse PRIV tags into a dictionary.
Definition: id3v2.c:1221
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
static int handle_id3(AVFormatContext *s, AVPacket *pkt)
Definition: aacdec.c:135
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:451
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:700
Main libavformat public API header.
static struct @323 state
int ff_id3v2_match(const uint8_t *buf, const char *magic)
Detect ID3v2 Header.
Definition: id3v2.c:143
int ffio_init_context(AVIOContext *s, unsigned char *buffer, int buffer_size, int write_flag, void *opaque, int(*read_packet)(void *opaque, uint8_t *buf, int buf_size), int(*write_packet)(void *opaque, uint8_t *buf, int buf_size), int64_t(*seek)(void *opaque, int64_t offset, int whence))
Definition: aviobuf.c:88
static int adts_aac_resync(AVFormatContext *s)
Definition: aacdec.c:83
void ff_id3v2_read_dict(AVIOContext *pb, AVDictionary **metadata, const char *magic, ID3v2ExtraMeta **extra_meta)
Read an ID3v2 tag into specified dictionary and retrieve supported extra metadata.
Definition: id3v2.c:1102
int eof_reached
true if was unable to read due to error or eof
Definition: avio.h:239
int ff_id3v2_tag_len(const uint8_t *buf)
Get the length of an ID3v2 tag.
Definition: id3v2.c:156
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:652
#define AV_DICT_IGNORE_SUFFIX
Return first entry in a dictionary whose first part corresponds to the search key, ignoring the suffix of the found key string.
Definition: dict.h:70
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1045
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:368
static int64_t fsize(FILE *f)
Definition: audiomatch.c:29
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: packet.h:340