FFmpeg: libavformat/smjpegdec.c Source File

FFmpeg

[フレーム]

libavformat

smjpegdec.c

Go to the documentation of this file.

1 /*

2 * SMJPEG 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 /**

23 * @file

24 * This is a demuxer for Loki SDL Motion JPEG files

25 */

27 #include "avformat.h"

28 #include "internal.h"

29 #include "riff.h"

30 #include "smjpeg.h"

32 typedef struct SMJPEGContext {

33 int audio_stream_index;

34 int video_stream_index;

35 } SMJPEGContext;

37 static int smjpeg_probe(AVProbeData *p)

38 {

39 if (!memcmp(p->buf, SMJPEG_MAGIC, 8))

40 return AVPROBE_SCORE_MAX;

41 return 0;

42 }

44 static int smjpeg_read_header(AVFormatContext *s)

45 {

46 SMJPEGContext *sc = s->priv_data;

47 AVStream *ast = NULL, *vst = NULL;

48 AVIOContext *pb = s->pb;

49 uint32_t version, htype, hlength, duration;

50 char *comment;

52 avio_skip(pb, 8); // magic

53 version = avio_rb32(pb);

54 if (version)

55 avpriv_request_sample(s, "Unknown version %d", version);

57 duration = avio_rb32(pb); // in msec

59 while (!url_feof(pb)) {

60 htype = avio_rl32(pb);

61 switch (htype) {

62 case SMJPEG_TXT:

63 hlength = avio_rb32(pb);

64 if (!hlength || hlength > 512)

65 return AVERROR_INVALIDDATA;

66 comment = av_malloc(hlength + 1);

67 if (!comment)

68 return AVERROR(ENOMEM);

69 if (avio_read(pb, comment, hlength) != hlength) {

70 av_freep(&comment);

71 av_log(s, AV_LOG_ERROR, "error when reading comment\n");

72 return AVERROR_INVALIDDATA;

73 }

74 comment[hlength] = 0;

75 av_dict_set(&s->metadata, "comment", comment,

76 AV_DICT_DONT_STRDUP_VAL);

77 break;

78 case SMJPEG_SND:

79 if (ast) {

80 avpriv_request_sample(s, "Multiple audio streams");

81 return AVERROR_PATCHWELCOME;

82 }

83 hlength = avio_rb32(pb);

84 if (hlength < 8)

85 return AVERROR_INVALIDDATA;

86 ast = avformat_new_stream(s, 0);

87 if (!ast)

88 return AVERROR(ENOMEM);

89 ast->codec->codec_type = AVMEDIA_TYPE_AUDIO;

90 ast->codec->sample_rate = avio_rb16(pb);

91 ast->codec->bits_per_coded_sample = avio_r8(pb);

92 ast->codec->channels = avio_r8(pb);

93 ast->codec->codec_tag = avio_rl32(pb);

94 ast->codec->codec_id = ff_codec_get_id(ff_codec_smjpeg_audio_tags,

95 ast->codec->codec_tag);

96 ast->duration = duration;

97 sc->audio_stream_index = ast->index;

98 avpriv_set_pts_info(ast, 32, 1, 1000);

99 avio_skip(pb, hlength - 8);

100 break;

101 case SMJPEG_VID:

102 if (vst) {

103 avpriv_request_sample(s, "Multiple video streams");

104 return AVERROR_INVALIDDATA;

105 }

106 hlength = avio_rb32(pb);

107 if (hlength < 12)

108 return AVERROR_INVALIDDATA;

109 vst = avformat_new_stream(s, 0);

110 if (!vst)

111 return AVERROR(ENOMEM);

112 vst->nb_frames = avio_rb32(pb);

113 vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;

114 vst->codec->width = avio_rb16(pb);

115 vst->codec->height = avio_rb16(pb);

116 vst->codec->codec_tag = avio_rl32(pb);

117 vst->codec->codec_id = ff_codec_get_id(ff_codec_smjpeg_video_tags,

118 vst->codec->codec_tag);

119 vst->duration = duration;

120 sc->video_stream_index = vst->index;

121 avpriv_set_pts_info(vst, 32, 1, 1000);

122 avio_skip(pb, hlength - 12);

123 break;

124 case SMJPEG_HEND:

125 return 0;

126 default:

127 av_log(s, AV_LOG_ERROR, "unknown header %x\n", htype);

128 return AVERROR_INVALIDDATA;

129 }

130 }

131

132 return AVERROR_EOF;

133 }

134

135 static int smjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)

136 {

137 SMJPEGContext *sc = s->priv_data;

138 uint32_t dtype, size, timestamp;

139 int64_t pos;

140 int ret;

141

142 if (url_feof(s->pb))

143 return AVERROR_EOF;

144 pos = avio_tell(s->pb);

145 dtype = avio_rl32(s->pb);

146 switch (dtype) {

147 case SMJPEG_SNDD:

148 timestamp = avio_rb32(s->pb);

149 size = avio_rb32(s->pb);

150 ret = av_get_packet(s->pb, pkt, size);

151 pkt->stream_index = sc->audio_stream_index;

152 pkt->pts = timestamp;

153 pkt->pos = pos;

154 break;

155 case SMJPEG_VIDD:

156 timestamp = avio_rb32(s->pb);

157 size = avio_rb32(s->pb);

158 ret = av_get_packet(s->pb, pkt, size);

159 pkt->stream_index = sc->video_stream_index;

160 pkt->pts = timestamp;

161 pkt->pos = pos;

162 break;

163 case SMJPEG_DONE:

164 ret = AVERROR_EOF;

165 break;

166 default:

167 av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", dtype);

168 ret = AVERROR_INVALIDDATA;

169 break;

170 }

171 return ret;

172 }

173

174 AVInputFormat ff_smjpeg_demuxer = {

175 .name = "smjpeg",

176 .long_name = NULL_IF_CONFIG_SMALL("Loki SDL MJPEG"),

177 .priv_data_size = sizeof(SMJPEGContext),

178 .read_probe = smjpeg_probe,

179 .read_header = smjpeg_read_header,

180 .read_packet = smjpeg_read_packet,

181 .extensions = "mjpg",

182 .flags = AVFMT_GENERIC_INDEX,

183 };

Generated on Sat Jan 25 2014 19:52:05 for FFmpeg by doxygen 1.8.2