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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 FFmpeg.
00006  *
00007  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "raw.h"
00025 #include "id3v2.h"
00026 #include "oggdec.h"
00027 #include "vorbiscomment.h"
00028 
00029 static int flac_read_header(AVFormatContext *s,
00030                              AVFormatParameters *ap)
00031 {
00032     uint8_t buf[ID3v2_HEADER_SIZE];
00033     int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
00034     uint8_t header[4];
00035     uint8_t *buffer=NULL;
00036     AVStream *st = av_new_stream(s, 0);
00037     if (!st)
00038         return AVERROR(ENOMEM);
00039     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00040     st->codec->codec_id = CODEC_ID_FLAC;
00041     st->need_parsing = AVSTREAM_PARSE_FULL;
00042     /* the parameters will be extracted from the compressed bitstream */
00043 
00044     /* skip ID3v2 header if found */
00045     ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
00046     if (ret == ID3v2_HEADER_SIZE && ff_id3v2_match(buf)) {
00047         int len = ff_id3v2_tag_len(buf);
00048         url_fseek(s->pb, len - ID3v2_HEADER_SIZE, SEEK_CUR);
00049     } else {
00050         url_fseek(s->pb, 0, SEEK_SET);
00051     }
00052 
00053     /* if fLaC marker is not found, assume there is no header */
00054     if (get_le32(s->pb) != MKTAG('f','L','a','C')) {
00055         url_fseek(s->pb, -4, SEEK_CUR);
00056         return 0;
00057     }
00058 
00059     /* process metadata blocks */
00060     while (!url_feof(s->pb) && !metadata_last) {
00061         get_buffer(s->pb, header, 4);
00062         ff_flac_parse_block_header(header, &metadata_last, &metadata_type,
00063                                    &metadata_size);
00064         switch (metadata_type) {
00065         /* allocate and read metadata block for supported types */
00066         case FLAC_METADATA_TYPE_STREAMINFO:
00067         case FLAC_METADATA_TYPE_VORBIS_COMMENT:
00068             buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE);
00069             if (!buffer) {
00070                 return AVERROR(ENOMEM);
00071             }
00072             if (get_buffer(s->pb, buffer, metadata_size) != metadata_size) {
00073                 av_freep(&buffer);
00074                 return AVERROR(EIO);
00075             }
00076             break;
00077         /* skip metadata block for unsupported types */
00078         default:
00079             ret = url_fseek(s->pb, metadata_size, SEEK_CUR);
00080             if (ret < 0)
00081                 return ret;
00082         }
00083 
00084         if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {
00085             FLACStreaminfo si;
00086             /* STREAMINFO can only occur once */
00087             if (found_streaminfo) {
00088                 av_freep(&buffer);
00089                 return AVERROR_INVALIDDATA;
00090             }
00091             if (metadata_size != FLAC_STREAMINFO_SIZE) {
00092                 av_freep(&buffer);
00093                 return AVERROR_INVALIDDATA;
00094             }
00095             found_streaminfo = 1;
00096             st->codec->extradata      = buffer;
00097             st->codec->extradata_size = metadata_size;
00098             buffer = NULL;
00099 
00100             /* get codec params from STREAMINFO header */
00101             ff_flac_parse_streaminfo(st->codec, &si, st->codec->extradata);
00102 
00103             /* set time base and duration */
00104             if (si.samplerate > 0) {
00105                 av_set_pts_info(st, 64, 1, si.samplerate);
00106                 if (si.samples > 0)
00107                     st->duration = si.samples;
00108             }
00109         } else {
00110             /* STREAMINFO must be the first block */
00111             if (!found_streaminfo) {
00112                 av_freep(&buffer);
00113                 return AVERROR_INVALIDDATA;
00114             }
00115             /* process supported blocks other than STREAMINFO */
00116             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
00117                 if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {
00118                     av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
00119                 }
00120             }
00121             av_freep(&buffer);
00122         }
00123     }
00124 
00125     return 0;
00126 }
00127 
00128 static int flac_probe(AVProbeData *p)
00129 {
00130     uint8_t *bufptr = p->buf;
00131     uint8_t *end    = p->buf + p->buf_size;
00132 
00133     if(ff_id3v2_match(bufptr))
00134         bufptr += ff_id3v2_tag_len(bufptr);
00135 
00136     if(bufptr > end-4 || memcmp(bufptr, "fLaC", 4)) return 0;
00137     else                                            return AVPROBE_SCORE_MAX/2;
00138 }
00139 
00140 AVInputFormat flac_demuxer = {
00141     "flac",
00142     NULL_IF_CONFIG_SMALL("raw FLAC"),
00143     0,
00144     flac_probe,
00145     flac_read_header,
00146     ff_raw_read_partial_packet,
00147     .flags= AVFMT_GENERIC_INDEX,
00148     .extensions = "flac",
00149     .value = CODEC_ID_FLAC,
00150     .metadata_conv = ff_vorbiscomment_metadata_conv,
00151 };

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