Libav 0.7.1
libavformat/flacdec.c
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00001 /*
00002  * Raw FLAC demuxer
00003  * Copyright (c) 2001 Fabrice Bellard
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavcodec/flac.h"
00023 #include "avformat.h"
00024 #include "rawdec.h"
00025 #include "oggdec.h"
00026 #include "vorbiscomment.h"
00027 
00028 static int flac_read_header(AVFormatContext *s,
00029                              AVFormatParameters *ap)
00030 {
00031     int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
00032     uint8_t header[4];
00033     uint8_t *buffer=NULL;
00034     AVStream *st = av_new_stream(s, 0);
00035     if (!st)
00036         return AVERROR(ENOMEM);
00037     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00038     st->codec->codec_id = CODEC_ID_FLAC;
00039     st->need_parsing = AVSTREAM_PARSE_FULL;
00040     /* the parameters will be extracted from the compressed bitstream */
00041 
00042     /* if fLaC marker is not found, assume there is no header */
00043     if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {
00044         avio_seek(s->pb, -4, SEEK_CUR);
00045         return 0;
00046     }
00047 
00048     /* process metadata blocks */
00049     while (!s->pb->eof_reached && !metadata_last) {
00050         avio_read(s->pb, header, 4);
00051         ff_flac_parse_block_header(header, &metadata_last, &metadata_type,
00052                                    &metadata_size);
00053         switch (metadata_type) {
00054         /* allocate and read metadata block for supported types */
00055         case FLAC_METADATA_TYPE_STREAMINFO:
00056         case FLAC_METADATA_TYPE_VORBIS_COMMENT:
00057             buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
00058             if (!buffer) {
00059                 return AVERROR(ENOMEM);
00060             }
00061             if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {
00062                 av_freep(&buffer);
00063                 return AVERROR(EIO);
00064             }
00065             break;
00066         /* skip metadata block for unsupported types */
00067         default:
00068             ret = avio_skip(s->pb, metadata_size);
00069             if (ret < 0)
00070                 return ret;
00071         }
00072 
00073         if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
00074             FLACStreaminfo si;
00075             /* STREAMINFO can only occur once */
00076             if (found_streaminfo) {
00077                 av_freep(&buffer);
00078                 return AVERROR_INVALIDDATA;
00079             }
00080             if (metadata_size != FLAC_STREAMINFO_SIZE) {
00081                 av_freep(&buffer);
00082                 return AVERROR_INVALIDDATA;
00083             }
00084             found_streaminfo = 1;
00085             st->codec->extradata      = buffer;
00086             st->codec->extradata_size = metadata_size;
00087             buffer = NULL;
00088 
00089             /* get codec params from STREAMINFO header */
00090             ff_flac_parse_streaminfo(st->codec, &si, st->codec->extradata);
00091 
00092             /* set time base and duration */
00093             if (si.samplerate > 0) {
00094                 av_set_pts_info(st, 64, 1, si.samplerate);
00095                 if (si.samples > 0)
00096                     st->duration = si.samples;
00097             }
00098         } else {
00099             /* STREAMINFO must be the first block */
00100             if (!found_streaminfo) {
00101                 av_freep(&buffer);
00102                 return AVERROR_INVALIDDATA;
00103             }
00104             /* process supported blocks other than STREAMINFO */
00105             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
00106                 if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {
00107                     av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
00108                 }
00109             }
00110             av_freep(&buffer);
00111         }
00112     }
00113 
00114     return 0;
00115 }
00116 
00117 static int flac_probe(AVProbeData *p)
00118 {
00119     uint8_t *bufptr = p->buf;
00120     uint8_t *end    = p->buf + p->buf_size;
00121 
00122     if(bufptr > end-4 || memcmp(bufptr, "fLaC", 4)) return 0;
00123     else                                            return AVPROBE_SCORE_MAX/2;
00124 }
00125 
00126 AVInputFormat ff_flac_demuxer = {
00127     "flac",
00128     NULL_IF_CONFIG_SMALL("raw FLAC"),
00129     0,
00130     flac_probe,
00131     flac_read_header,
00132     ff_raw_read_partial_packet,
00133     .flags= AVFMT_GENERIC_INDEX,
00134     .extensions = "flac",
00135     .value = CODEC_ID_FLAC,
00136 };