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flacdec.c
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1 /*
2  * Raw FLAC demuxer
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "flac_picture.h"
25 #include "internal.h"
26 #include "rawdec.h"
27 #include "oggdec.h"
28 #include "vorbiscomment.h"
29 #include "replaygain.h"
30 
32 {
33  int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
34  uint8_t header[4];
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 (!avio_feof(s->pb) && !metadata_last) {
52  avio_read(s->pb, header, 4);
53  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 */
61  buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
62  if (!buffer) {
63  return AVERROR(ENOMEM);
64  }
65  if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
66  RETURN_ERROR(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  uint32_t samplerate;
78  uint64_t samples;
79 
80  /* STREAMINFO can only occur once */
81  if (found_streaminfo) {
83  }
84  if (metadata_size != FLAC_STREAMINFO_SIZE) {
86  }
87  found_streaminfo = 1;
88  st->codec->extradata = buffer;
89  st->codec->extradata_size = metadata_size;
90  buffer = NULL;
91 
92  /* get sample rate and sample count from STREAMINFO header;
93  * other parameters will be extracted by the parser */
94  samplerate = AV_RB24(st->codec->extradata + 10) >> 4;
95  samples = (AV_RB64(st->codec->extradata + 13) >> 24) & ((1ULL << 36) - 1);
96 
97  /* set time base and duration */
98  if (samplerate > 0) {
99  avpriv_set_pts_info(st, 64, 1, samplerate);
100  if (samples > 0)
101  st->duration = samples;
102  }
103  } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
104  uint8_t isrc[13];
105  uint64_t start;
106  const uint8_t *offset;
107  int i, chapters, track, ti;
108  if (metadata_size < 431)
110  offset = buffer + 395;
111  chapters = bytestream_get_byte(&offset) - 1;
112  if (chapters <= 0)
114  for (i = 0; i < chapters; i++) {
115  if (offset + 36 - buffer > metadata_size)
117  start = bytestream_get_be64(&offset);
118  track = bytestream_get_byte(&offset);
119  bytestream_get_buffer(&offset, isrc, 12);
120  isrc[12] = 0;
121  offset += 14;
122  ti = bytestream_get_byte(&offset);
123  if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);
124  offset += ti * 12;
125  avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
126  }
127  av_freep(&buffer);
128  } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {
129  ret = ff_flac_parse_picture(s, buffer, metadata_size);
130  av_freep(&buffer);
131  if (ret < 0) {
132  av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");
133  return ret;
134  }
135  } else {
136  /* STREAMINFO must be the first block */
137  if (!found_streaminfo) {
139  }
140  /* process supported blocks other than STREAMINFO */
141  if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
142  AVDictionaryEntry *chmask;
143 
144  ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
145  if (ret < 0) {
146  av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
147  } else if (ret > 0) {
149  }
150 
151  /* parse the channels mask if present */
152  chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
153  if (chmask) {
154  uint64_t mask = strtol(chmask->value, NULL, 0);
155  if (!mask || mask & ~0x3ffffULL) {
157  "Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");
158  } else {
159  st->codec->channel_layout = mask;
160  av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
161  }
162  }
163  }
164  av_freep(&buffer);
165  }
166  }
167 
168  ret = ff_replaygain_export(st, s->metadata);
169  if (ret < 0)
170  return ret;
171 
172  return 0;
173 
174 fail:
175  av_free(buffer);
176  return ret;
177 }
178 
179 static int flac_probe(AVProbeData *p)
180 {
181  if (p->buf_size < 4 || memcmp(p->buf, "fLaC", 4))
182  return 0;
184 }
185 
186 static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,
187  int64_t *ppos, int64_t pos_limit)
188 {
189  AVPacket pkt, out_pkt;
190  AVStream *st = s->streams[stream_index];
191  AVCodecParserContext *parser;
192  int ret;
193  int64_t pts = AV_NOPTS_VALUE;
194 
195  if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)
196  return AV_NOPTS_VALUE;
197 
198  av_init_packet(&pkt);
199  parser = av_parser_init(st->codec->codec_id);
200  if (!parser){
201  return AV_NOPTS_VALUE;
202  }
203  parser->flags |= PARSER_FLAG_USE_CODEC_TS;
204 
205  for (;;){
206  ret = ff_raw_read_partial_packet(s, &pkt);
207  if (ret < 0){
208  if (ret == AVERROR(EAGAIN))
209  continue;
210  else
211  break;
212  }
213  av_init_packet(&out_pkt);
214  ret = av_parser_parse2(parser, st->codec,
215  &out_pkt.data, &out_pkt.size, pkt.data, pkt.size,
216  pkt.pts, pkt.dts, *ppos);
217 
218  av_free_packet(&pkt);
219  if (out_pkt.size){
220  int size = out_pkt.size;
221  if (parser->pts != AV_NOPTS_VALUE){
222  // seeking may not have started from beginning of a frame
223  // calculate frame start position from next frame backwards
224  *ppos = parser->next_frame_offset - size;
225  pts = parser->pts;
226  break;
227  }
228  }
229  }
230  av_parser_close(parser);
231  return pts;
232 }
233 
235  .name = "flac",
236  .long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
237  .read_probe = flac_probe,
238  .read_header = flac_read_header,
239  .read_packet = ff_raw_read_partial_packet,
240  .read_timestamp = flac_read_timestamp,
241  .flags = AVFMT_GENERIC_INDEX,
242  .extensions = "flac",
243  .raw_codec_id = AV_CODEC_ID_FLAC,
244 };