FFmpeg: libavformat/supdec.c Source File

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libavformat

supdec.c

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1 /*

2 * This file is part of FFmpeg.

3 *

4 * FFmpeg is free software; you can redistribute it and/or

5 * modify it under the terms of the GNU Lesser General Public

6 * License as published by the Free Software Foundation; either

7 * version 2.1 of the License, or (at your option) any later version.

8 *

9 * FFmpeg is distributed in the hope that it will be useful,

10 * but WITHOUT ANY WARRANTY; without even the implied warranty of

11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

12 * Lesser General Public License for more details.

13 *

14 * You should have received a copy of the GNU Lesser General Public

15 * License along with FFmpeg; if not, write to the Free Software

16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

17 */

19 #include "avformat.h"

20 #include "internal.h"

21 #include "libavutil/intreadwrite.h"

23 #define SUP_PGS_MAGIC 0x5047 /* "PG", big endian */

25 static int sup_read_header(AVFormatContext *s)

26 {

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

28 if (!st)

29 return AVERROR(ENOMEM);

30 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

31 st->codec->codec_id = AV_CODEC_ID_HDMV_PGS_SUBTITLE;

32 avpriv_set_pts_info(st, 32, 1, 90000);

34 return 0;

35 }

37 static int sup_read_packet(AVFormatContext *s, AVPacket *pkt)

38 {

39 int64_t pts, dts, pos;

40 int ret;

42 pos = avio_tell(s->pb);

44 if (avio_rb16(s->pb) != SUP_PGS_MAGIC)

45 return avio_feof(s->pb) ? AVERROR_EOF : AVERROR_INVALIDDATA;

47 pts = avio_rb32(s->pb);

48 dts = avio_rb32(s->pb);

50 if ((ret = av_get_packet(s->pb, pkt, 3)) < 0)

51 return ret;

53 pkt->stream_index = 0;

54 pkt->flags |= AV_PKT_FLAG_KEY;

55 pkt->pos = pos;

56 pkt->pts = pts;

57 // Many files have DTS set to 0 for all packets, so assume 0 means unset.

58 pkt->dts = dts ? dts : AV_NOPTS_VALUE;

60 if (pkt->size >= 3) {

61 // The full packet size is stored as part of the packet.

62 size_t len = AV_RB16(pkt->data + 1);

64 if ((ret = av_append_packet(s->pb, pkt, len)) < 0)

65 return ret;

66 }

68 return 0;

69 }

71 static int sup_probe(AVProbeData *p)

72 {

73 unsigned char *buf = p->buf;

74 size_t buf_size = p->buf_size;

75 int nb_packets;

77 for (nb_packets = 0; nb_packets < 10; nb_packets++) {

78 size_t full_packet_size;

79 if (buf_size < 10 + 3)

80 break;

81 if (AV_RB16(buf) != SUP_PGS_MAGIC)

82 return 0;

83 full_packet_size = AV_RB16(buf + 10 + 1) + 10 + 3;

84 if (buf_size < full_packet_size)

85 break;

86 buf += full_packet_size;

87 buf_size -= full_packet_size;

88 }

89 if (!nb_packets)

90 return 0;

91 if (nb_packets < 2)

92 return AVPROBE_SCORE_RETRY / 2;

93 if (nb_packets < 4)

94 return AVPROBE_SCORE_RETRY;

95 if (nb_packets < 10)

96 return AVPROBE_SCORE_EXTENSION;

97 return AVPROBE_SCORE_MAX;

98 }

100 AVInputFormat ff_sup_demuxer = {

101 .name = "sup",

102 .long_name = NULL_IF_CONFIG_SMALL("raw HDMV Presentation Graphic Stream subtitles"),

103 .extensions = "sup",

104 .mime_type = "application/x-pgs",

105 .read_probe = sup_probe,

106 .read_header = sup_read_header,

107 .read_packet = sup_read_packet,

108 .flags = AVFMT_GENERIC_INDEX,

109 };

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