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 <stdint.h>

37 #include "libavutil/intreadwrite.h"

38 #include "libavutil/mathematics.h"

39 #include "avformat.h"

40 #include "internal.h"

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

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

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

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

48 typedef struct Rl2DemuxContext {

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

50 } Rl2DemuxContext;

53 /**

54 * check if the file is in rl2 format

55 * @param p probe buffer

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

57 */

58 static int rl2_probe(AVProbeData *p)

59 {

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

62 return 0;

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

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

66 return 0;

68 return AVPROBE_SCORE_MAX;

69 }

71 /**

72 * read rl2 header data and setup the avstreams

73 * @param s demuxer context

74 * @return 0 on success, AVERROR otherwise

75 */

76 static av_cold int rl2_read_header(AVFormatContext *s)

77 {

78 AVIOContext *pb = s->pb;

79 AVStream *st;

80 unsigned int frame_count;

81 unsigned int audio_frame_counter = 0;

82 unsigned int video_frame_counter = 0;

83 unsigned int back_size;

84 unsigned short sound_rate;

85 unsigned short rate;

86 unsigned short channels;

87 unsigned short def_sound_size;

88 unsigned int signature;

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

90 unsigned int pts_num = 1103;

91 unsigned int* chunk_offset = NULL;

92 int* chunk_size = NULL;

93 int* audio_size = NULL;

94 int i;

95 int ret = 0;

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

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

99 signature = avio_rb32(pb);

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

101 frame_count = avio_rl32(pb);

102

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

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

105 return AVERROR_INVALIDDATA;

106

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

108 sound_rate = avio_rl16(pb);

109 rate = avio_rl16(pb);

110 channels = avio_rl16(pb);

111 def_sound_size = avio_rl16(pb);

112

113 /** setup video stream */

114 st = avformat_new_stream(s, NULL);

115 if(!st)

116 return AVERROR(ENOMEM);

117

118 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

119 st->codec->codec_id = AV_CODEC_ID_RL2;

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

121 st->codec->width = 320;

122 st->codec->height = 200;

123

124 /** allocate and fill extradata */

125 st->codec->extradata_size = EXTRADATA1_SIZE;

126

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

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

129

130 if(ff_get_extradata(st->codec, pb, st->codec->extradata_size) < 0)

131 return AVERROR(ENOMEM);

132

133 /** setup audio stream if present */

134 if(sound_rate){

135 if (!channels || channels > 42) {

136 av_log(s, AV_LOG_ERROR, "Invalid number of channels: %d\n", channels);

137 return AVERROR_INVALIDDATA;

138 }

139

140 pts_num = def_sound_size;

141 pts_den = rate;

142

143 st = avformat_new_stream(s, NULL);

144 if (!st)

145 return AVERROR(ENOMEM);

146 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

147 st->codec->codec_id = AV_CODEC_ID_PCM_U8;

148 st->codec->codec_tag = 1;

149 st->codec->channels = channels;

150 st->codec->bits_per_coded_sample = 8;

151 st->codec->sample_rate = rate;

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

153 st->codec->bits_per_coded_sample;

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

155 st->codec->bits_per_coded_sample / 8;

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

157 }

158

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

160

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

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

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

164

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

166 av_free(chunk_size);

167 av_free(audio_size);

168 av_free(chunk_offset);

169 return AVERROR(ENOMEM);

170 }

171

172 /** read offset and size tables */

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

174 chunk_size[i] = avio_rl32(pb);

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

176 chunk_offset[i] = avio_rl32(pb);

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

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

179

180 /** build the sample index */

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

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

183 ret = AVERROR_INVALIDDATA;

184 break;

185 }

186

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

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

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

190 audio_frame_counter += audio_size[i] / channels;

191 }

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

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

194 ++video_frame_counter;

195 }

196

197

198 av_free(chunk_size);

199 av_free(audio_size);

200 av_free(chunk_offset);

201

202 return ret;

203 }

204

205 /**

206 * read a single audio or video packet

207 * @param s demuxer context

208 * @param pkt the packet to be filled

209 * @return 0 on success, AVERROR otherwise

210 */

211 static int rl2_read_packet(AVFormatContext *s,

212 AVPacket *pkt)

213 {

214 Rl2DemuxContext *rl2 = s->priv_data;

215 AVIOContext *pb = s->pb;

216 AVIndexEntry *sample = NULL;

217 int i;

218 int ret = 0;

219 int stream_id = -1;

220 int64_t pos = INT64_MAX;

221

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

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

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

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

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

227 pos= sample->pos;

228 stream_id= i;

229 }

230 }

231

232 if(stream_id == -1)

233 return AVERROR_EOF;

234

235 ++rl2->index_pos[stream_id];

236

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

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

239

240 /** fill the packet */

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

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

243 av_free_packet(pkt);

244 return AVERROR(EIO);

245 }

246

247 pkt->stream_index = stream_id;

248 pkt->pts = sample->timestamp;

249

250 return ret;

251 }

252

253 /**

254 * seek to a new timestamp

255 * @param s demuxer context

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

257 * @param timestamp wanted timestamp

258 * @param flags direction and seeking mode

259 * @return 0 on success, -1 otherwise

260 */

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

262 {

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

264 Rl2DemuxContext *rl2 = s->priv_data;

265 int i;

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

267 if(index < 0)

268 return -1;

269

270 rl2->index_pos[stream_index] = index;

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

272

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

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

275 index = av_index_search_timestamp(st2,

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

277 flags | AVSEEK_FLAG_BACKWARD);

278

279 if(index < 0)

280 index = 0;

281

282 rl2->index_pos[i] = index;

283 }

284

285 return 0;

286 }

287

288 AVInputFormat ff_rl2_demuxer = {

289 .name = "rl2",

290 .long_name = NULL_IF_CONFIG_SMALL("RL2"),

291 .priv_data_size = sizeof(Rl2DemuxContext),

292 .read_probe = rl2_probe,

293 .read_header = rl2_read_header,

294 .read_packet = rl2_read_packet,

295 .read_seek = rl2_read_seek,

296 };

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