flacdec.c
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1 /*
2  * Raw FLAC demuxer
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavcodec/flac.h"
23 #include "avformat.h"
24 #include "internal.h"
25 #include "rawdec.h"
26 #include "oggdec.h"
27 #include "vorbiscomment.h"
28 #include "libavcodec/bytestream.h"
29 
32 {
33  int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
34  uint8_t header[4];
35  uint8_t *buffer=NULL;
37  if (!st)
38  return AVERROR(ENOMEM);
42  /* the parameters will be extracted from the compressed bitstream */
43 
44  /* if fLaC marker is not found, assume there is no header */
45  if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {
46  avio_seek(s->pb, -4, SEEK_CUR);
47  return 0;
48  }
49 
50  /* process metadata blocks */
51  while (!s->pb->eof_reached && !metadata_last) {
52  avio_read(s->pb, header, 4);
53  avpriv_flac_parse_block_header(header, &metadata_last, &metadata_type,
54  &metadata_size);
55  switch (metadata_type) {
56  /* allocate and read metadata block for supported types */
60  buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
61  if (!buffer) {
62  return AVERROR(ENOMEM);
63  }
64  if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
65  av_freep(&buffer);
66  return AVERROR(EIO);
67  }
68  break;
69  /* skip metadata block for unsupported types */
70  default:
71  ret = avio_skip(s->pb, metadata_size);
72  if (ret < 0)
73  return ret;
74  }
75 
76  if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
77  FLACStreaminfo si;
78  /* STREAMINFO can only occur once */
79  if (found_streaminfo) {
80  av_freep(&buffer);
81  return AVERROR_INVALIDDATA;
82  }
83  if (metadata_size != FLAC_STREAMINFO_SIZE) {
84  av_freep(&buffer);
85  return AVERROR_INVALIDDATA;
86  }
87  found_streaminfo = 1;
88  st->codec->extradata = buffer;
89  st->codec->extradata_size = metadata_size;
90  buffer = NULL;
91 
92  /* get codec params from STREAMINFO header */
94 
95  /* set time base and duration */
96  if (si.samplerate > 0) {
97  avpriv_set_pts_info(st, 64, 1, si.samplerate);
98  if (si.samples > 0)
99  st->duration = si.samples;
100  }
101  } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
102  uint8_t isrc[13];
103  uint64_t start;
104  const uint8_t *offset;
105  int i, chapters, track, ti;
106  if (metadata_size < 431)
107  return AVERROR_INVALIDDATA;
108  offset = buffer + 395;
109  chapters = bytestream_get_byte(&offset) - 1;
110  if (chapters <= 0)
111  return AVERROR_INVALIDDATA;
112  for (i = 0; i < chapters; i++) {
113  if (offset + 36 - buffer > metadata_size)
114  return AVERROR_INVALIDDATA;
115  start = bytestream_get_be64(&offset);
116  track = bytestream_get_byte(&offset);
117  bytestream_get_buffer(&offset, isrc, 12);
118  isrc[12] = 0;
119  offset += 14;
120  ti = bytestream_get_byte(&offset);
121  if (ti <= 0) return AVERROR_INVALIDDATA;
122  offset += ti * 12;
123  avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
124  }
125  } else {
126  /* STREAMINFO must be the first block */
127  if (!found_streaminfo) {
128  av_freep(&buffer);
129  return AVERROR_INVALIDDATA;
130  }
131  /* process supported blocks other than STREAMINFO */
132  if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
133  if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {
134  av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
135  }
136  }
137  av_freep(&buffer);
138  }
139  }
140 
141  return 0;
142 }
143 
144 static int flac_probe(AVProbeData *p)
145 {
146  if (p->buf_size < 4 || memcmp(p->buf, "fLaC", 4))
147  return 0;
148  return AVPROBE_SCORE_MAX/2;
149 }
150 
152  .name = "flac",
153  .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
154  .read_probe = flac_probe,
155  .read_header = flac_read_header,
156  .read_packet = ff_raw_read_partial_packet,
157  .flags= AVFMT_GENERIC_INDEX,
158  .extensions = "flac",
159  .value = CODEC_ID_FLAC,
160 };