FFmpeg: libavformat/rtpdec_xiph.c Source File

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libavformat

rtpdec_xiph.c

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1 /*

2 * Xiph RTP Protocols

5 *

6 * This file is part of FFmpeg.

7 *

8 * FFmpeg is free software; you can redistribute it and/or

9 * modify it under the terms of the GNU Lesser General Public

10 * License as published by the Free Software Foundation; either

11 * version 2.1 of the License, or (at your option) any later version.

12 *

13 * FFmpeg is distributed in the hope that it will be useful,

14 * but WITHOUT ANY WARRANTY; without even the implied warranty of

15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

16 * Lesser General Public License for more details.

17 *

18 * You should have received a copy of the GNU Lesser General Public

19 * License along with FFmpeg; if not, write to the Free Software

20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

21 */

23 /**

24 * @file

25 * @brief Xiph / RTP Code

26 * @author Colin McQuillan <m.niloc@gmail.com>

27 * @author Josh Allmann <joshua.allmann@gmail.com>

28 */

30 #include "libavutil/avassert.h"

31 #include "libavutil/avstring.h"

32 #include "libavutil/base64.h"

33 #include "libavcodec/bytestream.h"

35 #include "rtpdec.h"

36 #include "rtpdec_formats.h"

38 /**

39 * RTP/Xiph specific private data.

40 */

41 struct PayloadContext {

42 unsigned ident; ///< 24-bit stream configuration identifier

43 uint32_t timestamp;

44 AVIOContext* fragment; ///< buffer for split payloads

45 uint8_t *split_buf;

46 int split_pos, split_buf_len, split_buf_size;

47 int split_pkts;

48 };

50 static PayloadContext *xiph_new_context(void)

51 {

52 return av_mallocz(sizeof(PayloadContext));

53 }

55 static inline void free_fragment_if_needed(PayloadContext * data)

56 {

57 if (data->fragment) {

58 uint8_t* p;

59 avio_close_dyn_buf(data->fragment, &p);

60 av_free(p);

61 data->fragment = NULL;

62 }

63 }

65 static void xiph_free_context(PayloadContext * data)

66 {

67 free_fragment_if_needed(data);

68 av_free(data->split_buf);

69 av_free(data);

70 }

72 static int xiph_vorbis_init(AVFormatContext *ctx, int st_index,

73 PayloadContext *data)

74 {

75 if (st_index < 0)

76 return 0;

77 ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_HEADERS;

78 return 0;

79 }

82 static int xiph_handle_packet(AVFormatContext *ctx, PayloadContext *data,

83 AVStream *st, AVPacket *pkt, uint32_t *timestamp,

84 const uint8_t *buf, int len, uint16_t seq,

85 int flags)

86 {

88 int ident, fragmented, tdt, num_pkts, pkt_len;

90 if (!buf) {

91 if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||

92 data->split_pkts <= 0) {

93 av_log(ctx, AV_LOG_ERROR, "No more data to return\n");

94 return AVERROR_INVALIDDATA;

95 }

96 pkt_len = AV_RB16(data->split_buf + data->split_pos);

97 data->split_pos += 2;

98 if (data->split_pos + pkt_len > data->split_buf_len) {

99 av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");

100 return AVERROR_INVALIDDATA;

101 }

102 if (av_new_packet(pkt, pkt_len)) {

103 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");

104 return AVERROR(ENOMEM);

105 }

106 pkt->stream_index = st->index;

107 memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);

108 data->split_pos += pkt_len;

109 data->split_pkts--;

110 return data->split_pkts > 0;

111 }

112

113 if (len < 6) {

114 av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);

115 return AVERROR_INVALIDDATA;

116 }

117

118 // read xiph rtp headers

119 ident = AV_RB24(buf);

120 fragmented = buf[3] >> 6;

121 tdt = (buf[3] >> 4) & 3;

122 num_pkts = buf[3] & 0xf;

123 pkt_len = AV_RB16(buf + 4);

124

125 if (pkt_len > len - 6) {

126 av_log(ctx, AV_LOG_ERROR,

127 "Invalid packet length %d in %d byte packet\n", pkt_len,

128 len);

129 return AVERROR_INVALIDDATA;

130 }

131

132 if (ident != data->ident) {

133 av_log(ctx, AV_LOG_ERROR,

134 "Unimplemented Xiph SDP configuration change detected\n");

135 return AVERROR_PATCHWELCOME;

136 }

137

138 if (tdt) {

139 av_log(ctx, AV_LOG_ERROR,

140 "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",

141 fragmented, tdt, num_pkts);

142 return AVERROR_PATCHWELCOME;

143 }

144

145 buf += 6; // move past header bits

146 len -= 6;

147

148 if (fragmented == 0) {

149 if (av_new_packet(pkt, pkt_len)) {

150 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");

151 return AVERROR(ENOMEM);

152 }

153 pkt->stream_index = st->index;

154 memcpy(pkt->data, buf, pkt_len);

155 buf += pkt_len;

156 len -= pkt_len;

157 num_pkts--;

158

159 if (num_pkts > 0) {

160 if (len > data->split_buf_size || !data->split_buf) {

161 av_freep(&data->split_buf);

162 data->split_buf_size = 2 * len;

163 data->split_buf = av_malloc(data->split_buf_size);

164 if (!data->split_buf) {

165 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");

166 av_free_packet(pkt);

167 return AVERROR(ENOMEM);

168 }

169 }

170 memcpy(data->split_buf, buf, len);

171 data->split_buf_len = len;

172 data->split_pos = 0;

173 data->split_pkts = num_pkts;

174 return 1;

175 }

176

177 return 0;

178

179 } else if (fragmented == 1) {

180 // start of xiph data fragment

181 int res;

182

183 // end packet has been lost somewhere, so drop buffered data

184 free_fragment_if_needed(data);

185

186 if((res = avio_open_dyn_buf(&data->fragment)) < 0)

187 return res;

188

189 avio_write(data->fragment, buf, pkt_len);

190 data->timestamp = *timestamp;

191

192 } else {

193 av_assert1(fragmented < 4);

194 if (data->timestamp != *timestamp) {

195 // skip if fragmented timestamp is incorrect;

196 // a start packet has been lost somewhere

197 free_fragment_if_needed(data);

198 av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");

199 return AVERROR_INVALIDDATA;

200 }

201 if (!data->fragment) {

202 av_log(ctx, AV_LOG_WARNING,

203 "Received packet without a start fragment; dropping.\n");

204 return AVERROR(EAGAIN);

205 }

206

207 // copy data to fragment buffer

208 avio_write(data->fragment, buf, pkt_len);

209

210 if (fragmented == 3) {

211 // end of xiph data packet

212 int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);

213 if (ret < 0) {

214 av_log(ctx, AV_LOG_ERROR,

215 "Error occurred when getting fragment buffer.");

216 return ret;

217 }

218

219 return 0;

220 }

221 }

222

223 return AVERROR(EAGAIN);

224 }

225

226 /**

227 * Length encoding described in RFC5215 section 3.1.1.

228 */

229 static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)

230 {

231 int n = 0;

232 for (; *buf < buf_end; ++*buf) {

233 n <<= 7;

234 n += **buf & 0x7f;

235 if (!(**buf & 0x80)) {

236 ++*buf;

237 return n;

238 }

239 }

240 return 0;

241 }

242

243 /**

244 * Based off parse_packed_headers in Vorbis RTP

245 */

246 static int

247 parse_packed_headers(const uint8_t * packed_headers,

248 const uint8_t * packed_headers_end,

249 AVCodecContext * codec, PayloadContext * xiph_data)

250 {

251

252 unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;

253 uint8_t *ptr;

254

255 if (packed_headers_end - packed_headers < 9) {

256 av_log(codec, AV_LOG_ERROR,

257 "Invalid %td byte packed header.",

258 packed_headers_end - packed_headers);

259 return AVERROR_INVALIDDATA;

260 }

261

262 num_packed = bytestream_get_be32(&packed_headers);

263 xiph_data->ident = bytestream_get_be24(&packed_headers);

264 length = bytestream_get_be16(&packed_headers);

265 num_headers = get_base128(&packed_headers, packed_headers_end);

266 length1 = get_base128(&packed_headers, packed_headers_end);

267 length2 = get_base128(&packed_headers, packed_headers_end);

268

269 if (num_packed != 1 || num_headers > 3) {

270 av_log(codec, AV_LOG_ERROR,

271 "Unimplemented number of headers: %d packed headers, %d headers\n",

272 num_packed, num_headers);

273 return AVERROR_PATCHWELCOME;

274 }

275

276 if (packed_headers_end - packed_headers != length ||

277 length1 > length || length2 > length - length1) {

278 av_log(codec, AV_LOG_ERROR,

279 "Bad packed header lengths (%d,%d,%td,%d)\n", length1,

280 length2, packed_headers_end - packed_headers, length);

281 return AVERROR_INVALIDDATA;

282 }

283

284 /* allocate extra space:

285 * -- length/255 +2 for xiphlacing

286 * -- one for the '2' marker

287 * -- FF_INPUT_BUFFER_PADDING_SIZE required */

288 extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;

289

290 ptr = codec->extradata = av_malloc(extradata_alloc);

291 if (!ptr) {

292 av_log(codec, AV_LOG_ERROR, "Out of memory\n");

293 return AVERROR(ENOMEM);

294 }

295 *ptr++ = 2;

296 ptr += av_xiphlacing(ptr, length1);

297 ptr += av_xiphlacing(ptr, length2);

298 memcpy(ptr, packed_headers, length);

299 ptr += length;

300 codec->extradata_size = ptr - codec->extradata;

301 // clear out remaining parts of the buffer

302 memset(ptr, 0, extradata_alloc - codec->extradata_size);

303

304 return 0;

305 }

306

307 static int xiph_parse_fmtp_pair(AVStream* stream,

308 PayloadContext *xiph_data,

309 char *attr, char *value)

310 {

311 AVCodecContext *codec = stream->codec;

312 int result = 0;

313

314 if (!strcmp(attr, "sampling")) {

315 if (!strcmp(value, "YCbCr-4:2:0")) {

316 codec->pix_fmt = AV_PIX_FMT_YUV420P;

317 } else if (!strcmp(value, "YCbCr-4:4:2")) {

318 codec->pix_fmt = AV_PIX_FMT_YUV422P;

319 } else if (!strcmp(value, "YCbCr-4:4:4")) {

320 codec->pix_fmt = AV_PIX_FMT_YUV444P;

321 } else {

322 av_log(codec, AV_LOG_ERROR,

323 "Unsupported pixel format %s\n", attr);

324 return AVERROR_INVALIDDATA;

325 }

326 } else if (!strcmp(attr, "width")) {

327 /* This is an integer between 1 and 1048561

328 * and MUST be in multiples of 16. */

329 codec->width = atoi(value);

330 return 0;

331 } else if (!strcmp(attr, "height")) {

332 /* This is an integer between 1 and 1048561

333 * and MUST be in multiples of 16. */

334 codec->height = atoi(value);

335 return 0;

336 } else if (!strcmp(attr, "delivery-method")) {

337 /* Possible values are: inline, in_band, out_band/specific_name. */

338 return AVERROR_PATCHWELCOME;

339 } else if (!strcmp(attr, "configuration-uri")) {

340 /* NOTE: configuration-uri is supported only under 2 conditions:

341 *--after the delivery-method tag

342 * --with a delivery-method value of out_band */

343 return AVERROR_PATCHWELCOME;

344 } else if (!strcmp(attr, "configuration")) {

345 /* NOTE: configuration is supported only AFTER the delivery-method tag

346 * The configuration value is a base64 encoded packed header */

347 uint8_t *decoded_packet = NULL;

348 int packet_size;

349 size_t decoded_alloc = strlen(value) / 4 * 3 + 4;

350

351 if (decoded_alloc <= INT_MAX) {

352 decoded_packet = av_malloc(decoded_alloc);

353 if (decoded_packet) {

354 packet_size =

355 av_base64_decode(decoded_packet, value, decoded_alloc);

356

357 result = parse_packed_headers

358 (decoded_packet, decoded_packet + packet_size, codec,

359 xiph_data);

360 } else {

361 av_log(codec, AV_LOG_ERROR,

362 "Out of memory while decoding SDP configuration.\n");

363 result = AVERROR(ENOMEM);

364 }

365 } else {

366 av_log(codec, AV_LOG_ERROR, "Packet too large\n");

367 result = AVERROR_INVALIDDATA;

368 }

369 av_free(decoded_packet);

370 }

371 return result;

372 }

373

374 static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,

375 PayloadContext *data, const char *line)

376 {

377 const char *p;

378

379 if (st_index < 0)

380 return 0;

381

382 if (av_strstart(line, "fmtp:", &p)) {

383 return ff_parse_fmtp(s->streams[st_index], data, p,

384 xiph_parse_fmtp_pair);

385 }

386

387 return 0;

388 }

389

390 RTPDynamicProtocolHandler ff_theora_dynamic_handler = {

391 .enc_name = "theora",

392 .codec_type = AVMEDIA_TYPE_VIDEO,

393 .codec_id = AV_CODEC_ID_THEORA,

394 .parse_sdp_a_line = xiph_parse_sdp_line,

395 .alloc = xiph_new_context,

396 .free = xiph_free_context,

397 .parse_packet = xiph_handle_packet

398 };

399

400 RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {

401 .enc_name = "vorbis",

402 .codec_type = AVMEDIA_TYPE_AUDIO,

403 .codec_id = AV_CODEC_ID_VORBIS,

404 .init = xiph_vorbis_init,

405 .parse_sdp_a_line = xiph_parse_sdp_line,

406 .alloc = xiph_new_context,

407 .free = xiph_free_context,

408 .parse_packet = xiph_handle_packet

409 };

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