FFmpeg: libavformat/ffmetadec.c Source File

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libavformat

ffmetadec.c

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1 /*

2 * Metadata demuxer

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 */

22 #include "libavutil/mathematics.h"

23 #include "avformat.h"

24 #include "ffmeta.h"

25 #include "internal.h"

26 #include "libavutil/dict.h"

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 }

35 static void get_line(AVIOContext *s, uint8_t *buf, int size)

36 {

37 do {

38 uint8_t c;

39 int i = 0;

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;

49 if (i < size - 1)

50 buf[i++] = c;

51 }

52 buf[i] = 0;

53 } while (!url_feof(s) && (buf[0] == ';' || buf[0] == '#' || buf[0] == 0));

54 }

56 static AVChapter *read_chapter(AVFormatContext *s)

57 {

58 uint8_t line[256];

59 int64_t start, end;

60 AVRational tb = {1, 1e9};

62 get_line(s->pb, line, sizeof(line));

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));

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 }

78 return avpriv_new_chapter(s, s->nb_chapters, tb, start, end, NULL);

79 }

81 static uint8_t *unescape(uint8_t *buf, int size)

82 {

83 uint8_t *ret = av_malloc(size + 1);

84 uint8_t *p1 = ret, *p2 = buf;

86 if (!ret)

87 return NULL;

89 while (p2 < buf + size) {

90 if (*p2 == '\\')

91 p2++;

92 *p1++ = *p2++;

93 }

94 *p1 = 0;

95 return ret;

96 }

98 static int read_tag(uint8_t *line, AVDictionary **m)

99 {

100 uint8_t *key, *value, *p = line;

101

102 /* find first not escaped '=' */

103 while (1) {

104 if (*p == '=')

105 break;

106 else if (*p == '\\')

107 p++;

108

109 if (*p++)

110 continue;

111

112 return 0;

113 }

114

115 if (!(key = unescape(line, p - line)))

116 return AVERROR(ENOMEM);

117 if (!(value = unescape(p + 1, strlen(p + 1)))) {

118 av_free(key);

119 return AVERROR(ENOMEM);

120 }

121

122 av_dict_set(m, key, value, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);

123 return 0;

124 }

125

126 static int read_header(AVFormatContext *s)

127 {

128 AVDictionary **m = &s->metadata;

129 uint8_t line[1024];

130

131 while(!url_feof(s->pb)) {

132 get_line(s->pb, line, sizeof(line));

133

134 if (!memcmp(line, ID_STREAM, strlen(ID_STREAM))) {

135 AVStream *st = avformat_new_stream(s, NULL);

136

137 if (!st)

138 return AVERROR(ENOMEM);

139

140 st->codec->codec_type = AVMEDIA_TYPE_DATA;

141 st->codec->codec_id = AV_CODEC_ID_FFMETADATA;

142

143 m = &st->metadata;

144 } else if (!memcmp(line, ID_CHAPTER, strlen(ID_CHAPTER))) {

145 AVChapter *ch = read_chapter(s);

146

147 if (!ch)

148 return AVERROR(ENOMEM);

149

150 m = &ch->metadata;

151 } else

152 read_tag(line, m);

153 }

154

155 s->start_time = 0;

156 if (s->nb_chapters)

157 s->duration = av_rescale_q(s->chapters[s->nb_chapters - 1]->end,

158 s->chapters[s->nb_chapters - 1]->time_base,

159 AV_TIME_BASE_Q);

160

161 return 0;

162 }

163

164 static int read_packet(AVFormatContext *s, AVPacket *pkt)

165 {

166 return AVERROR_EOF;

167 }

168

169 AVInputFormat ff_ffmetadata_demuxer = {

170 .name = "ffmetadata",

171 .long_name = NULL_IF_CONFIG_SMALL("FFmpeg metadata in text"),

172 .read_probe = probe,

173 .read_header = read_header,

174 .read_packet = read_packet,

175 };

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