libavformat/flacdec.c

   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 "raw.h"
  25 #include "id3v2.h"
  26 #include "oggdec.h"
  27
  28 static int flac_read_header(AVFormatContext *s,
  29                              AVFormatParameters *ap)
  30 {
  31     uint8_t buf[ID3v2_HEADER_SIZE];
  32     int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
  33     uint8_t header[4];
  34     uint8_t *buffer=NULL;
  35     AVStream *st = av_new_stream(s, 0);
  36     if (!st)
  37         return AVERROR(ENOMEM);
  38     st->codec->codec_type = CODEC_TYPE_AUDIO;
  39     st->codec->codec_id = CODEC_ID_FLAC;
  40     st->need_parsing = AVSTREAM_PARSE_FULL;
  41     /* the parameters will be extracted from the compressed bitstream */
  42
  43     /* skip ID3v2 header if found */
  44     ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
  45     if (ret == ID3v2_HEADER_SIZE && ff_id3v2_match(buf)) {
  46         int len = ff_id3v2_tag_len(buf);
  47         url_fseek(s->pb, len - ID3v2_HEADER_SIZE, SEEK_CUR);
  48     } else {
  49         url_fseek(s->pb, 0, SEEK_SET);
  50     }
  51
  52     /* if fLaC marker is not found, assume there is no header */
  53     if (get_le32(s->pb) != MKTAG('f','L','a','C')) {
  54         url_fseek(s->pb, -4, SEEK_CUR);
  55         return 0;
  56     }
  57
  58     /* process metadata blocks */
  59     while (!url_feof(s->pb) && !metadata_last) {
  60         get_buffer(s->pb, header, 4);
  61         ff_flac_parse_block_header(header, &metadata_last, &metadata_type,
  62                                    &metadata_size);
  63         switch (metadata_type) {
  64         /* allocate and read metadata block for supported types */
  65         case FLAC_METADATA_TYPE_STREAMINFO:
  66         case FLAC_METADATA_TYPE_VORBIS_COMMENT:
  67             buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
  68             if (!buffer) {
  69                 return AVERROR_NOMEM;
  70             }
  71             if (get_buffer(s->pb, buffer, metadata_size) != metadata_size) {
  72                 av_freep(&buffer);
  73                 return AVERROR_IO;
  74             }
  75             break;
  76         /* skip metadata block for unsupported types */
  77         default:
  78             ret = url_fseek(s->pb, metadata_size, SEEK_CUR);
  79             if (ret < 0)
  80                 return ret;
  81         }
  82
  83         if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
  84             FLACStreaminfo si;
  85             /* STREAMINFO can only occur once */
  86             if (found_streaminfo) {
  87                 av_freep(&buffer);
  88                 return AVERROR_INVALIDDATA;
  89             }
  90             if (metadata_size != FLAC_STREAMINFO_SIZE) {
  91                 av_freep(&buffer);
  92                 return AVERROR_INVALIDDATA;
  93             }
  94             found_streaminfo = 1;
  95             st->codec->extradata      = buffer;
  96             st->codec->extradata_size = metadata_size;
  97             buffer = NULL;
  98
  99             /* get codec params from STREAMINFO header */
 100             ff_flac_parse_streaminfo(st->codec, &si, st->codec->extradata);
 101
 102             /* set time base and duration */
 103             if (si.samplerate > 0) {
 104                 av_set_pts_info(st, 64, 1, si.samplerate);
 105                 if (si.samples > 0)
 106                     st->duration = si.samples;
 107             }
 108         } else {
 109             /* STREAMINFO must be the first block */
 110             if (!found_streaminfo) {
 111                 av_freep(&buffer);
 112                 return AVERROR_INVALIDDATA;
 113             }
 114             /* process supported blocks other than STREAMINFO */
 115             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
 116                 if (vorbis_comment(s, buffer, metadata_size)) {
 117                     av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
 118                 }
 119             }
 120             av_freep(&buffer);
 121         }
 122     }
 123
 124     return 0;
 125 }
 126
 127 static int flac_probe(AVProbeData *p)
 128 {
 129     uint8_t *bufptr = p->buf;
 130     uint8_t *end    = p->buf + p->buf_size;
 131
 132     if(ff_id3v2_match(bufptr))
 133         bufptr += ff_id3v2_tag_len(bufptr);
 134
 135     if(bufptr > end-4 || memcmp(bufptr, "fLaC", 4)) return 0;
 136     else                                            return AVPROBE_SCORE_MAX/2;
 137 }
 138
 139 AVInputFormat flac_demuxer = {
 140     "flac",
 141     NULL_IF_CONFIG_SMALL("raw FLAC"),
 142     0,
 143     flac_probe,
 144     flac_read_header,
 145     ff_raw_read_partial_packet,
 146     .flags= AVFMT_GENERIC_INDEX,
 147     .extensions = "flac",
 148     .value = CODEC_ID_FLAC,
 149 };