FFmpeg: libavformat/idcin.c Source File

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libavformat

idcin.c

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1 /*

2 * id Quake II CIN File 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 * id Quake II CIN file demuxer by Mike Melanson (melanson@pcisys.net)

25 * For more information about the id CIN format, visit:

26 * http://www.csse.monash.edu.au/~timf/

27 *

28 * CIN is a somewhat quirky and ill-defined format. Here are some notes

29 * for anyone trying to understand the technical details of this format:

30 *

31 * The format has no definite file signature. This is problematic for a

32 * general-purpose media player that wants to automatically detect file

33 * types. However, a CIN file does start with 5 32-bit numbers that

34 * specify audio and video parameters. This demuxer gets around the lack

35 * of file signature by performing sanity checks on those parameters.

36 * Probabalistically, this is a reasonable solution since the number of

37 * valid combinations of the 5 parameters is a very small subset of the

38 * total 160-bit number space.

39 *

40 * Refer to the function idcin_probe() for the precise A/V parameters

41 * that this demuxer allows.

42 *

43 * Next, each audio and video frame has a duration of 1/14 sec. If the

44 * audio sample rate is a multiple of the common frequency 22050 Hz it will

45 * divide evenly by 14. However, if the sample rate is 11025 Hz:

46 * 11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)

47 * The way the CIN stores audio in this case is by storing 787 sample

48 * frames in the first audio frame and 788 sample frames in the second

49 * audio frame. Therefore, the total number of bytes in an audio frame

50 * is given as:

51 * audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame

52 * audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame

53 * audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame

54 * audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame

55 *

56 * Finally, not all id CIN creation tools agree on the resolution of the

57 * color palette, apparently. Some creation tools specify red, green, and

58 * blue palette components in terms of 6-bit VGA color DAC values which

59 * range from 0..63. Other tools specify the RGB components as full 8-bit

60 * values that range from 0..255. Since there are no markers in the file to

61 * differentiate between the two variants, this demuxer uses the following

62 * heuristic:

63 * - load the 768 palette bytes from disk

64 * - assume that they will need to be shifted left by 2 bits to

65 * transform them from 6-bit values to 8-bit values

66 * - scan through all 768 palette bytes

67 * - if any bytes exceed 63, do not shift the bytes at all before

68 * transmitting them to the video decoder

69 */

71 #include "libavutil/channel_layout.h"

72 #include "libavutil/imgutils.h"

73 #include "libavutil/intreadwrite.h"

74 #include "avformat.h"

75 #include "internal.h"

77 #define HUFFMAN_TABLE_SIZE (64 * 1024)

78 #define IDCIN_FPS 14

80 typedef struct IdcinDemuxContext {

81 int video_stream_index;

82 int audio_stream_index;

83 int audio_chunk_size1;

84 int audio_chunk_size2;

85 int block_align;

87 /* demux state variables */

88 int current_audio_chunk;

89 int next_chunk_is_video;

90 int audio_present;

91 int64_t first_pkt_pos;

92 } IdcinDemuxContext;

94 static int idcin_probe(AVProbeData *p)

95 {

96 unsigned int number, sample_rate;

98 /*

99 * This is what you could call a "probabilistic" file check: id CIN

100 * files don't have a definite file signature. In lieu of such a marker,

101 * perform sanity checks on the 5 32-bit header fields:

102 * width, height: greater than 0, less than or equal to 1024

103 * audio sample rate: greater than or equal to 8000, less than or

104 * equal to 48000, or 0 for no audio

105 * audio sample width (bytes/sample): 0 for no audio, or 1 or 2

106 * audio channels: 0 for no audio, or 1 or 2

107 */

108

109 /* check we have enough data to do all checks, otherwise the

110 0-padding may cause a wrong recognition */

111 if (p->buf_size < 20)

112 return 0;

113

114 /* check the video width */

115 number = AV_RL32(&p->buf[0]);

116 if ((number == 0) || (number > 1024))

117 return 0;

118

119 /* check the video height */

120 number = AV_RL32(&p->buf[4]);

121 if ((number == 0) || (number > 1024))

122 return 0;

123

124 /* check the audio sample rate */

125 sample_rate = AV_RL32(&p->buf[8]);

126 if (sample_rate && (sample_rate < 8000 || sample_rate > 48000))

127 return 0;

128

129 /* check the audio bytes/sample */

130 number = AV_RL32(&p->buf[12]);

131 if (number > 2 || sample_rate && !number)

132 return 0;

133

134 /* check the audio channels */

135 number = AV_RL32(&p->buf[16]);

136 if (number > 2 || sample_rate && !number)

137 return 0;

138

139 /* return half certainty since this check is a bit sketchy */

140 return AVPROBE_SCORE_EXTENSION;

141 }

142

143 static int idcin_read_header(AVFormatContext *s)

144 {

145 AVIOContext *pb = s->pb;

146 IdcinDemuxContext *idcin = s->priv_data;

147 AVStream *st;

148 unsigned int width, height;

149 unsigned int sample_rate, bytes_per_sample, channels;

150 int ret;

151

152 /* get the 5 header parameters */

153 width = avio_rl32(pb);

154 height = avio_rl32(pb);

155 sample_rate = avio_rl32(pb);

156 bytes_per_sample = avio_rl32(pb);

157 channels = avio_rl32(pb);

158

159 if (s->pb->eof_reached) {

160 av_log(s, AV_LOG_ERROR, "incomplete header\n");

161 return s->pb->error ? s->pb->error : AVERROR_EOF;

162 }

163

164 if (av_image_check_size(width, height, 0, s) < 0)

165 return AVERROR_INVALIDDATA;

166 if (sample_rate > 0) {

167 if (sample_rate < 14 || sample_rate > INT_MAX) {

168 av_log(s, AV_LOG_ERROR, "invalid sample rate: %u\n", sample_rate);

169 return AVERROR_INVALIDDATA;

170 }

171 if (bytes_per_sample < 1 || bytes_per_sample > 2) {

172 av_log(s, AV_LOG_ERROR, "invalid bytes per sample: %u\n",

173 bytes_per_sample);

174 return AVERROR_INVALIDDATA;

175 }

176 if (channels < 1 || channels > 2) {

177 av_log(s, AV_LOG_ERROR, "invalid channels: %u\n", channels);

178 return AVERROR_INVALIDDATA;

179 }

180 idcin->audio_present = 1;

181 } else {

182 /* if sample rate is 0, assume no audio */

183 idcin->audio_present = 0;

184 }

185

186 st = avformat_new_stream(s, NULL);

187 if (!st)

188 return AVERROR(ENOMEM);

189 avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);

190 st->start_time = 0;

191 idcin->video_stream_index = st->index;

192 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

193 st->codec->codec_id = AV_CODEC_ID_IDCIN;

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

195 st->codec->width = width;

196 st->codec->height = height;

197

198 /* load up the Huffman tables into extradata */

199 st->codec->extradata = av_malloc(HUFFMAN_TABLE_SIZE);

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

201 return AVERROR(ENOMEM);

202 st->codec->extradata_size = HUFFMAN_TABLE_SIZE;

203 ret = avio_read(pb, st->codec->extradata, HUFFMAN_TABLE_SIZE);

204 if (ret < 0) {

205 return ret;

206 } else if (ret != HUFFMAN_TABLE_SIZE) {

207 av_log(s, AV_LOG_ERROR, "incomplete header\n");

208 return AVERROR(EIO);

209 }

210

211 if (idcin->audio_present) {

212 idcin->audio_present = 1;

213 st = avformat_new_stream(s, NULL);

214 if (!st)

215 return AVERROR(ENOMEM);

216 avpriv_set_pts_info(st, 63, 1, sample_rate);

217 st->start_time = 0;

218 idcin->audio_stream_index = st->index;

219 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

220 st->codec->codec_tag = 1;

221 st->codec->channels = channels;

222 st->codec->channel_layout = channels > 1 ? AV_CH_LAYOUT_STEREO :

223 AV_CH_LAYOUT_MONO;

224 st->codec->sample_rate = sample_rate;

225 st->codec->bits_per_coded_sample = bytes_per_sample * 8;

226 st->codec->bit_rate = sample_rate * bytes_per_sample * 8 * channels;

227 st->codec->block_align = idcin->block_align = bytes_per_sample * channels;

228 if (bytes_per_sample == 1)

229 st->codec->codec_id = AV_CODEC_ID_PCM_U8;

230 else

231 st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;

232

233 if (sample_rate % 14 != 0) {

234 idcin->audio_chunk_size1 = (sample_rate / 14) *

235 bytes_per_sample * channels;

236 idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *

237 bytes_per_sample * channels;

238 } else {

239 idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =

240 (sample_rate / 14) * bytes_per_sample * channels;

241 }

242 idcin->current_audio_chunk = 0;

243 }

244

245 idcin->next_chunk_is_video = 1;

246 idcin->first_pkt_pos = avio_tell(s->pb);

247

248 return 0;

249 }

250

251 static int idcin_read_packet(AVFormatContext *s,

252 AVPacket *pkt)

253 {

254 int ret;

255 unsigned int command;

256 unsigned int chunk_size;

257 IdcinDemuxContext *idcin = s->priv_data;

258 AVIOContext *pb = s->pb;

259 int i;

260 int palette_scale;

261 unsigned char r, g, b;

262 unsigned char palette_buffer[768];

263 uint32_t palette[256];

264

265 if (url_feof(s->pb))

266 return s->pb->error ? s->pb->error : AVERROR_EOF;

267

268 if (idcin->next_chunk_is_video) {

269 command = avio_rl32(pb);

270 if (command == 2) {

271 return AVERROR(EIO);

272 } else if (command == 1) {

273 /* trigger a palette change */

274 ret = avio_read(pb, palette_buffer, 768);

275 if (ret < 0) {

276 return ret;

277 } else if (ret != 768) {

278 av_log(s, AV_LOG_ERROR, "incomplete packet\n");

279 return AVERROR(EIO);

280 }

281 /* scale the palette as necessary */

282 palette_scale = 2;

283 for (i = 0; i < 768; i++)

284 if (palette_buffer[i] > 63) {

285 palette_scale = 0;

286 break;

287 }

288

289 for (i = 0; i < 256; i++) {

290 r = palette_buffer[i * 3 ] << palette_scale;

291 g = palette_buffer[i * 3 + 1] << palette_scale;

292 b = palette_buffer[i * 3 + 2] << palette_scale;

293 palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);

294 if (palette_scale == 2)

295 palette[i] |= palette[i] >> 6 & 0x30303;

296 }

297 }

298

299 if (s->pb->eof_reached) {

300 av_log(s, AV_LOG_ERROR, "incomplete packet\n");

301 return s->pb->error ? s->pb->error : AVERROR_EOF;

302 }

303 chunk_size = avio_rl32(pb);

304 if (chunk_size < 4 || chunk_size > INT_MAX - 4) {

305 av_log(s, AV_LOG_ERROR, "invalid chunk size: %u\n", chunk_size);

306 return AVERROR_INVALIDDATA;

307 }

308 /* skip the number of decoded bytes (always equal to width * height) */

309 avio_skip(pb, 4);

310 if (chunk_size < 4)

311 return AVERROR_INVALIDDATA;

312 chunk_size -= 4;

313 ret= av_get_packet(pb, pkt, chunk_size);

314 if (ret < 0)

315 return ret;

316 else if (ret != chunk_size) {

317 av_log(s, AV_LOG_ERROR, "incomplete packet\n");

318 av_free_packet(pkt);

319 return AVERROR(EIO);

320 }

321 if (command == 1) {

322 uint8_t *pal;

323

324 pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,

325 AVPALETTE_SIZE);

326 if (!pal) {

327 av_free_packet(pkt);

328 return AVERROR(ENOMEM);

329 }

330 memcpy(pal, palette, AVPALETTE_SIZE);

331 pkt->flags |= AV_PKT_FLAG_KEY;

332 }

333 pkt->stream_index = idcin->video_stream_index;

334 pkt->duration = 1;

335 } else {

336 /* send out the audio chunk */

337 if (idcin->current_audio_chunk)

338 chunk_size = idcin->audio_chunk_size2;

339 else

340 chunk_size = idcin->audio_chunk_size1;

341 ret= av_get_packet(pb, pkt, chunk_size);

342 if (ret < 0)

343 return ret;

344 pkt->stream_index = idcin->audio_stream_index;

345 pkt->duration = chunk_size / idcin->block_align;

346

347 idcin->current_audio_chunk ^= 1;

348 }

349

350 if (idcin->audio_present)

351 idcin->next_chunk_is_video ^= 1;

352

353 return 0;

354 }

355

356 static int idcin_read_seek(AVFormatContext *s, int stream_index,

357 int64_t timestamp, int flags)

358 {

359 IdcinDemuxContext *idcin = s->priv_data;

360

361 if (idcin->first_pkt_pos > 0) {

362 int ret = avio_seek(s->pb, idcin->first_pkt_pos, SEEK_SET);

363 if (ret < 0)

364 return ret;

365 ff_update_cur_dts(s, s->streams[idcin->video_stream_index], 0);

366 idcin->next_chunk_is_video = 1;

367 idcin->current_audio_chunk = 0;

368 return 0;

369 }

370 return -1;

371 }

372

373 AVInputFormat ff_idcin_demuxer = {

374 .name = "idcin",

375 .long_name = NULL_IF_CONFIG_SMALL("id Cinematic"),

376 .priv_data_size = sizeof(IdcinDemuxContext),

377 .read_probe = idcin_probe,

378 .read_header = idcin_read_header,

379 .read_packet = idcin_read_packet,

380 .read_seek = idcin_read_seek,

381 .flags = AVFMT_NO_BYTE_SEEK,

382 };

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