FFmpeg: libavformat/lrcenc.c Source File

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libavformat

lrcenc.c

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1 /*

2 * LRC lyrics file format decoder

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 <inttypes.h>

23 #include <stdint.h>

24 #include <string.h>

26 #include "avformat.h"

27 #include "internal.h"

28 #include "lrc.h"

29 #include "metadata.h"

30 #include "subtitles.h"

31 #include "version.h"

32 #include "libavutil/bprint.h"

33 #include "libavutil/dict.h"

34 #include "libavutil/log.h"

35 #include "libavutil/macros.h"

37 static int lrc_write_header(AVFormatContext *s)

38 {

39 const AVDictionaryEntry *metadata_item;

41 if(s->nb_streams != 1 ||

42 s->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {

43 av_log(s, AV_LOG_ERROR,

44 "LRC supports only a single subtitle stream.\n");

45 return AVERROR(EINVAL);

46 }

47 if(s->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP &&

48 s->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT) {

49 av_log(s, AV_LOG_ERROR, "Unsupported subtitle codec: %s\n",

50 avcodec_get_name(s->streams[0]->codec->codec_id));

51 return AVERROR(EINVAL);

52 }

53 avpriv_set_pts_info(s->streams[0], 64, 1, 100);

55 ff_metadata_conv_ctx(s, ff_lrc_metadata_conv, NULL);

56 if(!(s->flags & AVFMT_FLAG_BITEXACT)) { // avoid breaking regression tests

57 /* LRC provides a metadata slot for specifying encoder version

58 * in addition to encoder name. We will store LIBAVFORMAT_VERSION

59 * to it.

60 */

61 av_dict_set(&s->metadata, "ve", AV_STRINGIFY(LIBAVFORMAT_VERSION), 0);

62 } else {

63 av_dict_set(&s->metadata, "ve", NULL, 0);

64 }

65 for(metadata_item = NULL;

66 (metadata_item = av_dict_get(s->metadata, "", metadata_item,

67 AV_DICT_IGNORE_SUFFIX));) {

68 char *delim;

69 if(!metadata_item->value[0]) {

70 continue;

71 }

72 while((delim = strchr(metadata_item->value, '\n'))) {

73 *delim = ' ';

74 }

75 while((delim = strchr(metadata_item->value, '\r'))) {

76 *delim = ' ';

77 }

78 avio_printf(s->pb, "[%s:%s]\n",

79 metadata_item->key, metadata_item->value);

80 }

81 avio_printf(s->pb, "\n");

82 return 0;

83 }

85 static int lrc_write_packet(AVFormatContext *s, AVPacket *pkt)

86 {

87 if(pkt->pts != AV_NOPTS_VALUE) {

88 char *data = av_malloc(pkt->size + 1);

89 char *line;

90 char *delim;

92 if(!data) {

93 return AVERROR(ENOMEM);

94 }

95 memcpy(data, pkt->data, pkt->size);

96 data[pkt->size] = '0円';

98 for(delim = data + pkt->size - 1;

99 delim >= data && (delim[0] == '\n' || delim[0] == '\r'); delim--) {

100 delim[0] = '0円'; // Strip last empty lines

101 }

102 line = data;

103 while(line[0] == '\n' || line[0] == '\r') {

104 line++; // Skip first empty lines

105 }

106

107 while(line) {

108 delim = strchr(line, '\n');

109 if(delim) {

110 if(delim > line && delim[-1] == '\r') {

111 delim[-1] = '0円';

112 }

113 delim[0] = '0円';

114 delim++;

115 }

116 if(line[0] == '[') {

117 av_log(s, AV_LOG_WARNING,

118 "Subtitle starts with '[', may cause problems with LRC format.\n");

119 }

120

121 if(pkt->pts >= 0) {

122 avio_printf(s->pb, "[%02"PRId64":%02"PRId64".%02"PRId64"]",

123 (pkt->pts / 6000),

124 ((pkt->pts / 100) % 60),

125 (pkt->pts % 100));

126 } else {

127 /* Offset feature of LRC can easily make pts negative,

128 * we just output it directly and let the player drop it. */

129 avio_printf(s->pb, "[-%02"PRId64":%02"PRId64".%02"PRId64"]",

130 (-pkt->pts) / 6000,

131 ((-pkt->pts) / 100) % 60,

132 (-pkt->pts) % 100);

133 }

134 avio_printf(s->pb, "%s\n", line);

135 line = delim;

136 }

137 av_free(data);

138 }

139 return 0;

140 }

141

142 AVOutputFormat ff_lrc_muxer = {

143 .name = "lrc",

144 .long_name = NULL_IF_CONFIG_SMALL("LRC lyrics"),

145 .extensions = "lrc",

146 .priv_data_size = 0,

147 .write_header = lrc_write_header,

148 .write_packet = lrc_write_packet,

149 .flags = AVFMT_VARIABLE_FPS | AVFMT_GLOBALHEADER |

150 AVFMT_TS_NEGATIVE | AVFMT_TS_NONSTRICT,

151 .subtitle_codec = AV_CODEC_ID_SUBRIP

152 };

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