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libavformat/ffmetadec.c

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00001 /*
00002  * Metadata demuxer
00003  * Copyright (c) 2010 Anton Khirnov
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 "avformat.h"
00023 #include "ffmeta.h"
00024 #include "internal.h"
00025 #include "libavutil/dict.h"
00026 
00027 static int probe(AVProbeData *p)
00028 {
00029     if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
00030         return AVPROBE_SCORE_MAX;
00031     return 0;
00032 }
00033 
00034 static void get_line(AVIOContext *s, uint8_t *buf, int size)
00035 {
00036     do {
00037         uint8_t c;
00038         int i = 0;
00039 
00040         while ((c = avio_r8(s))) {
00041             if (c == '\\') {
00042                 if (i < size - 1)
00043                     buf[i++] = c;
00044                 c = avio_r8(s);
00045             } else if (c == '\n')
00046                 break;
00047 
00048             if (i < size - 1)
00049                 buf[i++] = c;
00050         }
00051         buf[i] = 0;
00052     } while (!url_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
00053 }
00054 
00055 static AVChapter *read_chapter(AVFormatContext *s)
00056 {
00057     uint8_t line[256];
00058     int64_t start, end;
00059     AVRational tb = {1, 1e9};
00060 
00061     get_line(s->pb, line, sizeof(line));
00062 
00063     if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
00064         get_line(s->pb, line, sizeof(line));
00065     if (!sscanf(line, "START=%"SCNd64, &start)) {
00066         av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
00067         start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
00068                  s->chapters[s->nb_chapters - 1]->end : 0;
00069     } else
00070         get_line(s->pb, line, sizeof(line));
00071 
00072     if (!sscanf(line, "END=%"SCNd64, &end)) {
00073         av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
00074         end = AV_NOPTS_VALUE;
00075     }
00076 
00077     return ff_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
00078 }
00079 
00080 static uint8_t *unescape(uint8_t *buf, int size)
00081 {
00082     uint8_t *ret = av_malloc(size + 1);
00083     uint8_t *p1  = ret, *p2 = buf;
00084 
00085     if (!ret)
00086         return NULL;
00087 
00088     while (p2 < buf + size) {
00089         if (*p2 == '\\')
00090             p2++;
00091         *p1++ = *p2++;
00092     }
00093     *p1 = 0;
00094     return ret;
00095 }
00096 
00097 static int read_tag(uint8_t *line, AVDictionary **m)
00098 {
00099     uint8_t *key, *value, *p = line;
00100 
00101     /* find first not escaped '=' */
00102     while (1) {
00103         if (*p == '=')
00104             break;
00105         else if (*p == '\\')
00106             p++;
00107 
00108         if (*p++)
00109             continue;
00110 
00111         return 0;
00112     }
00113 
00114     if (!(key = unescape(line, p - line)))
00115         return AVERROR(ENOMEM);
00116     if (!(value = unescape(p + 1, strlen(p + 1)))) {
00117         av_free(key);
00118         return AVERROR(ENOMEM);
00119     }
00120 
00121     av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
00122     return 0;
00123 }
00124 
00125 static int read_header(AVFormatContext *s, AVFormatParameters *ap)
00126 {
00127     AVDictionary **m = &s->metadata;
00128     uint8_t line[1024];
00129 
00130     while(!url_feof(s->pb)) {
00131         get_line(s->pb, line, sizeof(line));
00132 
00133         if (!memcmp(line, ID_STREAM, strlen(ID_STREAM))) {
00134             AVStream *st = av_new_stream(s, 0);
00135 
00136             if (!st)
00137                 return -1;
00138 
00139             st->codec->codec_type = AVMEDIA_TYPE_DATA;
00140             st->codec->codec_id   = CODEC_ID_FFMETADATA;
00141 
00142             m = &st->metadata;
00143         } else if (!memcmp(line, ID_CHAPTER, strlen(ID_CHAPTER))) {
00144             AVChapter *ch = read_chapter(s);
00145 
00146             if (!ch)
00147                 return -1;
00148 
00149             m = &ch->metadata;
00150         } else
00151             read_tag(line, m);
00152     }
00153 
00154     s->start_time = 0;
00155     if (s->nb_chapters)
00156         s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
00157                                    s->chapters[s->nb_chapters - 1]->time_base,
00158                                    AV_TIME_BASE_Q);
00159 
00160     return 0;
00161 }
00162 
00163 static int read_packet(AVFormatContext *s, AVPacket *pkt)
00164 {
00165     return AVERROR_EOF;
00166 }
00167 
00168 AVInputFormat ff_ffmetadata_demuxer = {
00169     .name        = "ffmetadata",
00170     .long_name   = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text format"),
00171     .read_probe  = probe,
00172     .read_header = read_header,
00173     .read_packet = read_packet,
00174 };

Generated on Wed Apr 11 2012 07:31:36 for FFmpeg by  doxygen 1.7.1