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  1. /*
  2.  * Metadata demuxer
  3.  * Copyright (c) 2010 Anton Khirnov
  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 "libavutil/mathematics.h"
  23. #include "avformat.h"
  24. #include "ffmeta.h"
  25. #include "internal.h"
  26. #include "libavutil/dict.h"
  27.  
  28. static int probe(AVProbeData *p)
  29. {
  30.     if(!memcmp(p->buf, ID_STRING, strlen(ID_STRING)))
  31.         return AVPROBE_SCORE_MAX;
  32.     return 0;
  33. }
  34.  
  35. static void get_line(AVIOContext *s, uint8_t *buf, int size)
  36. {
  37.     do {
  38.         uint8_t c;
  39.         int i = 0;
  40.  
  41.         while ((c = avio_r8(s))) {
  42.             if (c == '\\') {
  43.                 if (i < size - 1)
  44.                     buf[i++] = c;
  45.                 c = avio_r8(s);
  46.             } else if (c == '\n')
  47.                 break;
  48.  
  49.             if (i < size - 1)
  50.                 buf[i++] = c;
  51.         }
  52.         buf[i] = 0;
  53.     } while (!avio_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));
  54. }
  55.  
  56. static AVChapter *read_chapter(AVFormatContext *s)
  57. {
  58.     uint8_t line[256];
  59.     int64_t start, end;
  60.     AVRational tb = {1, 1e9};
  61.  
  62.     get_line(s->pb, line, sizeof(line));
  63.  
  64.     if (sscanf(line, "TIMEBASE=%d/%d", &tb.num, &tb.den))
  65.         get_line(s->pb, line, sizeof(line));
  66.     if (!sscanf(line, "START=%"SCNd64, &start)) {
  67.         av_log(s, AV_LOG_ERROR, "Expected chapter start timestamp, found %s.\n", line);
  68.         start = (s->nb_chapters && s->chapters[s->nb_chapters - 1]->end != AV_NOPTS_VALUE) ?
  69.                  s->chapters[s->nb_chapters - 1]->end : 0;
  70.     } else
  71.         get_line(s->pb, line, sizeof(line));
  72.  
  73.     if (!sscanf(line, "END=%"SCNd64, &end)) {
  74.         av_log(s, AV_LOG_ERROR, "Expected chapter end timestamp, found %s.\n", line);
  75.         end = AV_NOPTS_VALUE;
  76.     }
  77.  
  78.     return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);
  79. }
  80.  
  81. static uint8_t *unescape(const uint8_t *buf, int size)
  82. {
  83.     uint8_t *ret = av_malloc(size + 1);
  84.     uint8_t *p1  = ret;
  85.     const uint8_t *p2 = buf;
  86.  
  87.     if (!ret)
  88.         return NULL;
  89.  
  90.     while (p2 < buf + size) {
  91.         if (*p2 == '\\')
  92.             p2++;
  93.         *p1++ = *p2++;
  94.     }
  95.     *p1 = 0;
  96.     return ret;
  97. }
  98.  
  99. static int read_tag(const uint8_t *line, AVDictionary **m)
  100. {
  101.     uint8_t *key, *value;
  102.     const uint8_t *p = line;
  103.  
  104.     /* find first not escaped '=' */
  105.     while (1) {
  106.         if (*p == '=')
  107.             break;
  108.         else if (*p == '\\')
  109.             p++;
  110.  
  111.         if (*p++)
  112.             continue;
  113.  
  114.         return 0;
  115.     }
  116.  
  117.     if (!(key = unescape(line, p - line)))
  118.         return AVERROR(ENOMEM);
  119.     if (!(value = unescape(p + 1, strlen(p + 1)))) {
  120.         av_free(key);
  121.         return AVERROR(ENOMEM);
  122.     }
  123.  
  124.     av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
  125.     return 0;
  126. }
  127.  
  128. static int read_header(AVFormatContext *s)
  129. {
  130.     AVDictionary **m = &s->metadata;
  131.     uint8_t line[1024];
  132.  
  133.     while(!avio_feof(s->pb)) {
  134.         get_line(s->pb, line, sizeof(line));
  135.  
  136.         if (!memcmp(line, ID_STREAM, strlen(ID_STREAM))) {
  137.             AVStream *st = avformat_new_stream(s, NULL);
  138.  
  139.             if (!st)
  140.                 return AVERROR(ENOMEM);
  141.  
  142.             st->codec->codec_type = AVMEDIA_TYPE_DATA;
  143.             st->codec->codec_id   = AV_CODEC_ID_FFMETADATA;
  144.  
  145.             m = &st->metadata;
  146.         } else if (!memcmp(line, ID_CHAPTER, strlen(ID_CHAPTER))) {
  147.             AVChapter *ch = read_chapter(s);
  148.  
  149.             if (!ch)
  150.                 return AVERROR(ENOMEM);
  151.  
  152.             m = &ch->metadata;
  153.         } else
  154.             read_tag(line, m);
  155.     }
  156.  
  157.     s->start_time = 0;
  158.     if (s->nb_chapters)
  159.         s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,
  160.                                    s->chapters[s->nb_chapters - 1]->time_base,
  161.                                    AV_TIME_BASE_Q);
  162.  
  163.     return 0;
  164. }
  165.  
  166. static int read_packet(AVFormatContext *s, AVPacket *pkt)
  167. {
  168.     return AVERROR_EOF;
  169. }
  170.  
  171. AVInputFormat ff_ffmetadata_demuxer = {
  172.     .name        = "ffmetadata",
  173.     .long_name   = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),
  174.     .read_probe  = probe,
  175.     .read_header = read_header,
  176.     .read_packet = read_packet,
  177. };
  178.