FFmpeg: libavformat/dfa.c Source File

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libavformat

dfa.c

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1 /*

2 * Chronomaster DFA Format 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/intreadwrite.h"

23 #include "avformat.h"

24 #include "internal.h"

26 static int dfa_probe(AVProbeData *p)

27 {

28 if (p->buf_size < 4 || AV_RL32(p->buf) != MKTAG('D', 'F', 'I', 'A'))

29 return 0;

31 return AVPROBE_SCORE_MAX;

32 }

34 static int dfa_read_header(AVFormatContext *s)

35 {

36 AVIOContext *pb = s->pb;

37 AVStream *st;

38 int frames;

39 int version;

40 uint32_t mspf;

42 if (avio_rl32(pb) != MKTAG('D', 'F', 'I', 'A')) {

43 av_log(s, AV_LOG_ERROR, "Invalid magic for DFA\n");

44 return AVERROR_INVALIDDATA;

45 }

47 version = avio_rl16(pb);

48 frames = avio_rl16(pb);

50 st = avformat_new_stream(s, NULL);

51 if (!st)

52 return AVERROR(ENOMEM);

54 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

55 st->codec->codec_id = AV_CODEC_ID_DFA;

56 st->codec->width = avio_rl16(pb);

57 st->codec->height = avio_rl16(pb);

58 mspf = avio_rl32(pb);

59 if (!mspf) {

60 av_log(s, AV_LOG_WARNING, "Zero FPS reported, defaulting to 10\n");

61 mspf = 100;

62 }

63 avpriv_set_pts_info(st, 24, mspf, 1000);

64 avio_skip(pb, 128 - 16); // padding

65 st->duration = frames;

67 if (ff_alloc_extradata(st->codec, 2))

68 return AVERROR(ENOMEM);

69 AV_WL16(st->codec->extradata, version);

70 if (version == 0x100)

71 st->sample_aspect_ratio = (AVRational){2, 1};

73 return 0;

74 }

76 static int dfa_read_packet(AVFormatContext *s, AVPacket *pkt)

77 {

78 AVIOContext *pb = s->pb;

79 uint32_t frame_size;

80 int ret, first = 1;

82 if (pb->eof_reached)

83 return AVERROR_EOF;

85 if (av_get_packet(pb, pkt, 12) != 12)

86 return AVERROR(EIO);

87 while (!pb->eof_reached) {

88 if (!first) {

89 ret = av_append_packet(pb, pkt, 12);

90 if (ret < 0) {

91 av_free_packet(pkt);

92 return ret;

93 }

94 } else

95 first = 0;

96 frame_size = AV_RL32(pkt->data + pkt->size - 8);

97 if (frame_size > INT_MAX - 4) {

98 av_log(s, AV_LOG_ERROR, "Too large chunk size: %d\n", frame_size);

99 return AVERROR(EIO);

100 }

101 if (AV_RL32(pkt->data + pkt->size - 12) == MKTAG('E', 'O', 'F', 'R')) {

102 if (frame_size) {

103 av_log(s, AV_LOG_WARNING, "skipping %d bytes of end-of-frame marker chunk\n",

104 frame_size);

105 avio_skip(pb, frame_size);

106 }

107 return 0;

108 }

109 ret = av_append_packet(pb, pkt, frame_size);

110 if (ret < 0) {

111 av_free_packet(pkt);

112 return ret;

113 }

114 }

115

116 return 0;

117 }

118

119 AVInputFormat ff_dfa_demuxer = {

120 .name = "dfa",

121 .long_name = NULL_IF_CONFIG_SMALL("Chronomaster DFA"),

122 .read_probe = dfa_probe,

123 .read_header = dfa_read_header,

124 .read_packet = dfa_read_packet,

125 .flags = AVFMT_GENERIC_INDEX,

126 };

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