FFmpeg: libavformat/rl2.c Source File

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libavformat

rl2.c

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1 /*

2 * RL2 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 /**

23 * RL2 file demuxer

24 * @file

25 * @author Sascha Sommer (saschasommer@freenet.de)

26 * @see http://wiki.multimedia.cx/index.php?title=RL2

27 *

28 * extradata:

29 * 2 byte le initial drawing offset within 320x200 viewport

30 * 4 byte le number of used colors

31 * 256 * 3 bytes rgb palette

32 * optional background_frame

33 */

35 #include "libavutil/intreadwrite.h"

36 #include "libavutil/mathematics.h"

37 #include "avformat.h"

38 #include "internal.h"

40 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr, palette

42 #define FORM_TAG MKBETAG('F', 'O', 'R', 'M')

43 #define RLV2_TAG MKBETAG('R', 'L', 'V', '2')

44 #define RLV3_TAG MKBETAG('R', 'L', 'V', '3')

46 typedef struct Rl2DemuxContext {

47 unsigned int index_pos[2]; ///< indexes in the sample tables

48 } Rl2DemuxContext;

51 /**

52 * check if the file is in rl2 format

53 * @param p probe buffer

54 * @return 0 when the probe buffer does not contain rl2 data, > 0 otherwise

55 */

56 static int rl2_probe(AVProbeData *p)

57 {

59 if(AV_RB32(&p->buf[0]) != FORM_TAG)

60 return 0;

62 if(AV_RB32(&p->buf[8]) != RLV2_TAG &&

63 AV_RB32(&p->buf[8]) != RLV3_TAG)

64 return 0;

66 return AVPROBE_SCORE_MAX;

67 }

69 /**

70 * read rl2 header data and setup the avstreams

71 * @param s demuxer context

72 * @return 0 on success, AVERROR otherwise

73 */

74 static av_cold int rl2_read_header(AVFormatContext *s)

75 {

76 AVIOContext *pb = s->pb;

77 AVStream *st;

78 unsigned int frame_count;

79 unsigned int audio_frame_counter = 0;

80 unsigned int video_frame_counter = 0;

81 unsigned int back_size;

82 unsigned short sound_rate;

83 unsigned short rate;

84 unsigned short channels;

85 unsigned short def_sound_size;

86 unsigned int signature;

87 unsigned int pts_den = 11025; /* video only case */

88 unsigned int pts_num = 1103;

89 unsigned int* chunk_offset = NULL;

90 int* chunk_size = NULL;

91 int* audio_size = NULL;

92 int i;

93 int ret = 0;

95 avio_skip(pb,4); /* skip FORM tag */

96 back_size = avio_rl32(pb); /**< get size of the background frame */

97 signature = avio_rb32(pb);

98 avio_skip(pb, 4); /* data size */

99 frame_count = avio_rl32(pb);

100

101 /* disallow back_sizes and frame_counts that may lead to overflows later */

102 if(back_size > INT_MAX/2 || frame_count > INT_MAX / sizeof(uint32_t))

103 return AVERROR_INVALIDDATA;

104

105 avio_skip(pb, 2); /* encoding mentod */

106 sound_rate = avio_rl16(pb);

107 rate = avio_rl16(pb);

108 channels = avio_rl16(pb);

109 def_sound_size = avio_rl16(pb);

110

111 /** setup video stream */

112 st = avformat_new_stream(s, NULL);

113 if(!st)

114 return AVERROR(ENOMEM);

115

116 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

117 st->codec->codec_id = AV_CODEC_ID_RL2;

118 st->codec->codec_tag = 0; /* no fourcc */

119 st->codec->width = 320;

120 st->codec->height = 200;

121

122 /** allocate and fill extradata */

123 st->codec->extradata_size = EXTRADATA1_SIZE;

124

125 if(signature == RLV3_TAG && back_size > 0)

126 st->codec->extradata_size += back_size;

127

128 st->codec->extradata = av_mallocz(st->codec->extradata_size +

129 FF_INPUT_BUFFER_PADDING_SIZE);

130 if(!st->codec->extradata)

131 return AVERROR(ENOMEM);

132

133 if(avio_read(pb,st->codec->extradata,st->codec->extradata_size) !=

134 st->codec->extradata_size)

135 return AVERROR(EIO);

136

137 /** setup audio stream if present */

138 if(sound_rate){

139 if(channels <= 0)

140 return AVERROR_INVALIDDATA;

141

142 pts_num = def_sound_size;

143 pts_den = rate;

144

145 st = avformat_new_stream(s, NULL);

146 if (!st)

147 return AVERROR(ENOMEM);

148 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

149 st->codec->codec_id = AV_CODEC_ID_PCM_U8;

150 st->codec->codec_tag = 1;

151 st->codec->channels = channels;

152 st->codec->bits_per_coded_sample = 8;

153 st->codec->sample_rate = rate;

154 st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *

155 st->codec->bits_per_coded_sample;

156 st->codec->block_align = st->codec->channels *

157 st->codec->bits_per_coded_sample / 8;

158 avpriv_set_pts_info(st,32,1,rate);

159 }

160

161 avpriv_set_pts_info(s->streams[0], 32, pts_num, pts_den);

162

163 chunk_size = av_malloc(frame_count * sizeof(uint32_t));

164 audio_size = av_malloc(frame_count * sizeof(uint32_t));

165 chunk_offset = av_malloc(frame_count * sizeof(uint32_t));

166

167 if(!chunk_size || !audio_size || !chunk_offset){

168 av_free(chunk_size);

169 av_free(audio_size);

170 av_free(chunk_offset);

171 return AVERROR(ENOMEM);

172 }

173

174 /** read offset and size tables */

175 for(i=0; i < frame_count;i++)

176 chunk_size[i] = avio_rl32(pb);

177 for(i=0; i < frame_count;i++)

178 chunk_offset[i] = avio_rl32(pb);

179 for(i=0; i < frame_count;i++)

180 audio_size[i] = avio_rl32(pb) & 0xFFFF;

181

182 /** build the sample index */

183 for(i=0;i<frame_count;i++){

184 if(chunk_size[i] < 0 || audio_size[i] > chunk_size[i]){

185 ret = AVERROR_INVALIDDATA;

186 break;

187 }

188

189 if(sound_rate && audio_size[i]){

190 av_add_index_entry(s->streams[1], chunk_offset[i],

191 audio_frame_counter,audio_size[i], 0, AVINDEX_KEYFRAME);

192 audio_frame_counter += audio_size[i] / channels;

193 }

194 av_add_index_entry(s->streams[0], chunk_offset[i] + audio_size[i],

195 video_frame_counter,chunk_size[i]-audio_size[i],0,AVINDEX_KEYFRAME);

196 ++video_frame_counter;

197 }

198

199

200 av_free(chunk_size);

201 av_free(audio_size);

202 av_free(chunk_offset);

203

204 return ret;

205 }

206

207 /**

208 * read a single audio or video packet

209 * @param s demuxer context

210 * @param pkt the packet to be filled

211 * @return 0 on success, AVERROR otherwise

212 */

213 static int rl2_read_packet(AVFormatContext *s,

214 AVPacket *pkt)

215 {

216 Rl2DemuxContext *rl2 = s->priv_data;

217 AVIOContext *pb = s->pb;

218 AVIndexEntry *sample = NULL;

219 int i;

220 int ret = 0;

221 int stream_id = -1;

222 int64_t pos = INT64_MAX;

223

224 /** check if there is a valid video or audio entry that can be used */

225 for(i=0; i<s->nb_streams; i++){

226 if(rl2->index_pos[i] < s->streams[i]->nb_index_entries

227 && s->streams[i]->index_entries[ rl2->index_pos[i] ].pos < pos){

228 sample = &s->streams[i]->index_entries[ rl2->index_pos[i] ];

229 pos= sample->pos;

230 stream_id= i;

231 }

232 }

233

234 if(stream_id == -1)

235 return AVERROR_EOF;

236

237 ++rl2->index_pos[stream_id];

238

239 /** position the stream (will probably be there anyway) */

240 avio_seek(pb, sample->pos, SEEK_SET);

241

242 /** fill the packet */

243 ret = av_get_packet(pb, pkt, sample->size);

244 if(ret != sample->size){

245 av_free_packet(pkt);

246 return AVERROR(EIO);

247 }

248

249 pkt->stream_index = stream_id;

250 pkt->pts = sample->timestamp;

251

252 return ret;

253 }

254

255 /**

256 * seek to a new timestamp

257 * @param s demuxer context

258 * @param stream_index index of the stream that should be seeked

259 * @param timestamp wanted timestamp

260 * @param flags direction and seeking mode

261 * @return 0 on success, -1 otherwise

262 */

263 static int rl2_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)

264 {

265 AVStream *st = s->streams[stream_index];

266 Rl2DemuxContext *rl2 = s->priv_data;

267 int i;

268 int index = av_index_search_timestamp(st, timestamp, flags);

269 if(index < 0)

270 return -1;

271

272 rl2->index_pos[stream_index] = index;

273 timestamp = st->index_entries[index].timestamp;

274

275 for(i=0; i < s->nb_streams; i++){

276 AVStream *st2 = s->streams[i];

277 index = av_index_search_timestamp(st2,

278 av_rescale_q(timestamp, st->time_base, st2->time_base),

279 flags | AVSEEK_FLAG_BACKWARD);

280

281 if(index < 0)

282 index = 0;

283

284 rl2->index_pos[i] = index;

285 }

286

287 return 0;

288 }

289

290 AVInputFormat ff_rl2_demuxer = {

291 .name = "rl2",

292 .long_name = NULL_IF_CONFIG_SMALL("RL2"),

293 .priv_data_size = sizeof(Rl2DemuxContext),

294 .read_probe = rl2_probe,

295 .read_header = rl2_read_header,

296 .read_packet = rl2_read_packet,

297 .read_seek = rl2_read_seek,

298 };

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