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smjpegdec.c
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1 /*
2  * SMJPEG demuxer
3  * Copyright (c) 2011 Paul B Mahol
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  */
21 
22 /**
23  * @file
24  * This is a demuxer for Loki SDL Motion JPEG files
25  */
26 
27 #include "avformat.h"
28 #include "internal.h"
29 #include "riff.h"
30 #include "smjpeg.h"
31 
32 typedef struct SMJPEGContext {
36 
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 }
43 
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;
51 
52  avio_skip(pb, 8); // magic
53  version = avio_rb32(pb);
54  if (version)
55  av_log_ask_for_sample(s, "unknown version %d\n", version);
56 
57  duration = avio_rb32(pb); // in msec
58 
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,
77  break;
78  case SMJPEG_SND:
79  if (ast) {
80  av_log_ask_for_sample(s, "multiple audio streams not supported\n");
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);
90  ast->codec->sample_rate = avio_rb16(pb);
92  ast->codec->channels = avio_r8(pb);
93  ast->codec->codec_tag = avio_rl32(pb);
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  av_log_ask_for_sample(s, "multiple video streams not supported\n");
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 
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 
175  .name = "smjpeg",
176  .long_name = NULL_IF_CONFIG_SMALL("Loki SDL MJPEG"),
177  .priv_data_size = sizeof(SMJPEGContext),
181  .extensions = "mjpg",
183 };