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  av_packet_unref(pkt);
145  return ret;
146  }
147 
148  ffio_init_context(&ioctx, pkt->data, pkt->size, 0, NULL, NULL, NULL, NULL);
149  ff_id3v2_read_dict(&ioctx, &metadata, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);
150  if ((ret = ff_id3v2_parse_priv_dict(&metadata, &id3v2_extra_meta)) < 0)
151  goto error;
152 
153  if (metadata) {
154  if ((ret = av_dict_copy(&s->metadata, metadata, 0)) < 0)
155  goto error;
157  }
158 
159 error:
160  av_packet_unref(pkt);
161  ff_id3v2_free_extra_meta(&id3v2_extra_meta);
162  av_dict_free(&metadata);
163 
164  return ret;
165 }
166 
168 {
169  int ret, fsize;
170 
171 retry:
172  ret = av_get_packet(s->pb, pkt, ADTS_HEADER_SIZE);
173  if (ret < 0)
174  return ret;
175 
176  if (ret < ADTS_HEADER_SIZE) {
177  av_packet_unref(pkt);
178  return AVERROR(EIO);
179  }
180 
181  if ((AV_RB16(pkt->data) >> 4) != 0xfff) {
182  // Parse all the ID3 headers between frames
184 
185  av_assert2(append > 0);
186  ret = av_append_packet(s->pb, pkt, append);
187  if (ret != append) {
188  av_packet_unref(pkt);
189  return AVERROR(EIO);
190  }
192  av_packet_unref(pkt);
193  ret = adts_aac_resync(s);
194  } else
195  ret = handle_id3(s, pkt);
196  if (ret < 0)
197  return ret;
198 
199  goto retry;
200  }
201 
202  fsize = (AV_RB32(pkt->data + 3) >> 13) & 0x1FFF;
203  if (fsize < ADTS_HEADER_SIZE) {
204  av_packet_unref(pkt);
205  return AVERROR_INVALIDDATA;
206  }
207 
208  ret = av_append_packet(s->pb, pkt, fsize - pkt->size);
209  if (ret < 0)
210  av_packet_unref(pkt);
211 
212  return ret;
213 }
214 
216  .name = "aac",
217  .long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"),
218  .read_probe = adts_aac_probe,
219  .read_header = adts_aac_read_header,
220  .read_packet = adts_aac_read_packet,
221  .flags = AVFMT_GENERIC_INDEX,
222  .extensions = "aac",
223  .mime_type = "audio/aac,audio/aacp,audio/x-aac",
224  .raw_codec_id = AV_CODEC_ID_AAC,
225 };
int64_t probesize
Maximum size of the data read from input for determining the input container format.
Definition: avformat.h:1524
#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:4926
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3968
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:235
int size
Definition: avcodec.h:1481
#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:246
int event_flags
Flags for the user to detect events happening on the file.
Definition: avformat.h:1673
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
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:87
if it could not because there are no more frames
static int adts_aac_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: aacdec.c:167
Format I/O context.
Definition: avformat.h:1358
#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:90
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
int ff_id3v2_parse_priv_dict(AVDictionary **metadata, ID3v2ExtraMeta **extra_meta)
Parse PRIV tags into a dictionary.
Definition: id3v2.c:1234
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4499
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:87
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: avcodec.h:1480
#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:310
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:804
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:320
#define ADTS_HEADER_SIZE
Definition: aacdec.c:32
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
AVInputFormat ff_aac_demuxer
Definition: aacdec.c:215
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
ff_const59 struct AVInputFormat * iformat
The input container format.
Definition: avformat.h:1370
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: avcodec.h:3964
void ff_id3v2_free_extra_meta(ID3v2ExtraMeta **extra_meta)
Free memory allocated parsing special (non-text) metadata.
Definition: id3v2.c:1127
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:641
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
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
The call resulted in updated metadata.
Definition: avformat.h:1674
#define s(width, name)
Definition: cbs_vp9.c:257
static void error(const char *err)
Stream structure.
Definition: avformat.h:881
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:599
void * buf
Definition: avisynth_c.h:766
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
static int handle_id3(AVFormatContext *s, AVPacket *pkt)
Definition: aacdec.c:135
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
int raw_codec_id
Raw demuxers store their codec ID here.
Definition: avformat.h:700
Main libavformat public API header.
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:81
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:1115
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
static struct @316 state
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
#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:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
static int64_t fsize(FILE *f)
Definition: audiomatch.c:28
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: avcodec.h:1457