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/attributes.h"

31 #include "libavutil/avassert.h"

32 #include "libavutil/avstring.h"

33 #include "libavutil/base64.h"

34 #include "libavcodec/bytestream.h"

36 #include "internal.h"

37 #include "rtpdec.h"

38 #include "rtpdec_formats.h"

40 /**

41 * RTP/Xiph specific private data.

42 */

43 struct PayloadContext {

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

45 uint32_t timestamp;

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

47 uint8_t *split_buf;

48 int split_pos, split_buf_len, split_buf_size;

49 int split_pkts;

50 };

52 static PayloadContext *xiph_new_context(void)

53 {

54 return av_mallocz(sizeof(PayloadContext));

55 }

57 static inline void free_fragment_if_needed(PayloadContext * data)

58 {

59 if (data->fragment) {

60 uint8_t* p;

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

62 av_free(p);

63 data->fragment = NULL;

64 }

65 }

67 static void xiph_free_context(PayloadContext * data)

68 {

69 free_fragment_if_needed(data);

70 av_free(data->split_buf);

71 av_free(data);

72 }

74 static av_cold int xiph_vorbis_init(AVFormatContext *ctx, int st_index,

75 PayloadContext *data)

76 {

77 if (st_index < 0)

78 return 0;

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

80 return 0;

81 }

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

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

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

87 int flags)

88 {

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

92 if (!buf) {

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

94 data->split_pkts <= 0) {

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

96 return AVERROR_INVALIDDATA;

97 }

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

99 data->split_pos += 2;

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

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

102 return AVERROR_INVALIDDATA;

103 }

104 if (av_new_packet(pkt, pkt_len)) {

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

106 return AVERROR(ENOMEM);

107 }

108 pkt->stream_index = st->index;

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

110 data->split_pos += pkt_len;

111 data->split_pkts--;

112 return data->split_pkts > 0;

113 }

114

115 if (len < 6) {

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

117 return AVERROR_INVALIDDATA;

118 }

119

120 // read xiph rtp headers

121 ident = AV_RB24(buf);

122 fragmented = buf[3] >> 6;

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

124 num_pkts = buf[3] & 0xf;

125 pkt_len = AV_RB16(buf + 4);

126

127 if (pkt_len > len - 6) {

128 av_log(ctx, AV_LOG_ERROR,

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

130 len);

131 return AVERROR_INVALIDDATA;

132 }

133

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

135 av_log(ctx, AV_LOG_ERROR,

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

137 return AVERROR_PATCHWELCOME;

138 }

139

140 if (tdt) {

141 av_log(ctx, AV_LOG_ERROR,

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

143 fragmented, tdt, num_pkts);

144 return AVERROR_PATCHWELCOME;

145 }

146

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

148 len -= 6;

149

150 if (fragmented == 0) {

151 if (av_new_packet(pkt, pkt_len)) {

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

153 return AVERROR(ENOMEM);

154 }

155 pkt->stream_index = st->index;

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

157 buf += pkt_len;

158 len -= pkt_len;

159 num_pkts--;

160

161 if (num_pkts > 0) {

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

163 av_freep(&data->split_buf);

164 data->split_buf_size = 2 * len;

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

166 if (!data->split_buf) {

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

168 av_free_packet(pkt);

169 return AVERROR(ENOMEM);

170 }

171 }

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

173 data->split_buf_len = len;

174 data->split_pos = 0;

175 data->split_pkts = num_pkts;

176 return 1;

177 }

178

179 return 0;

180

181 } else if (fragmented == 1) {

182 // start of xiph data fragment

183 int res;

184

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

186 free_fragment_if_needed(data);

187

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

189 return res;

190

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

192 data->timestamp = *timestamp;

193

194 } else {

195 av_assert1(fragmented < 4);

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

197 // skip if fragmented timestamp is incorrect;

198 // a start packet has been lost somewhere

199 free_fragment_if_needed(data);

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

201 return AVERROR_INVALIDDATA;

202 }

203 if (!data->fragment) {

204 av_log(ctx, AV_LOG_WARNING,

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

206 return AVERROR(EAGAIN);

207 }

208

209 // copy data to fragment buffer

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

211

212 if (fragmented == 3) {

213 // end of xiph data packet

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

215 if (ret < 0) {

216 av_log(ctx, AV_LOG_ERROR,

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

218 return ret;

219 }

220

221 return 0;

222 }

223 }

224

225 return AVERROR(EAGAIN);

226 }

227

228 /**

229 * Length encoding described in RFC5215 section 3.1.1.

230 */

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

232 {

233 int n = 0;

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

235 n <<= 7;

236 n += **buf & 0x7f;

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

238 ++*buf;

239 return n;

240 }

241 }

242 return 0;

243 }

244

245 /**

246 * Based off parse_packed_headers in Vorbis RTP

247 */

248 static int

249 parse_packed_headers(const uint8_t * packed_headers,

250 const uint8_t * packed_headers_end,

251 AVCodecContext * codec, PayloadContext * xiph_data)

252 {

253

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

255 uint8_t *ptr;

256

257 if (packed_headers_end - packed_headers < 9) {

258 av_log(codec, AV_LOG_ERROR,

259 "Invalid %td byte packed header.",

260 packed_headers_end - packed_headers);

261 return AVERROR_INVALIDDATA;

262 }

263

264 num_packed = bytestream_get_be32(&packed_headers);

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

266 length = bytestream_get_be16(&packed_headers);

267 num_headers = get_base128(&packed_headers, packed_headers_end);

268 length1 = get_base128(&packed_headers, packed_headers_end);

269 length2 = get_base128(&packed_headers, packed_headers_end);

270

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

272 av_log(codec, AV_LOG_ERROR,

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

274 num_packed, num_headers);

275 return AVERROR_PATCHWELCOME;

276 }

277

278 if (packed_headers_end - packed_headers != length ||

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

280 av_log(codec, AV_LOG_ERROR,

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

282 length2, packed_headers_end - packed_headers, length);

283 return AVERROR_INVALIDDATA;

284 }

285

286 /* allocate extra space:

287 * -- length/255 +2 for xiphlacing

288 * -- one for the '2' marker

289 * -- FF_INPUT_BUFFER_PADDING_SIZE required */

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

291

292 if (ff_alloc_extradata(codec, extradata_alloc)) {

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

294 return AVERROR(ENOMEM);

295 }

296 ptr = codec->extradata;

297 *ptr++ = 2;

298 ptr += av_xiphlacing(ptr, length1);

299 ptr += av_xiphlacing(ptr, length2);

300 memcpy(ptr, packed_headers, length);

301 ptr += length;

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

303 // clear out remaining parts of the buffer

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

305

306 return 0;

307 }

308

309 static int xiph_parse_fmtp_pair(AVStream* stream,

310 PayloadContext *xiph_data,

311 char *attr, char *value)

312 {

313 AVCodecContext *codec = stream->codec;

314 int result = 0;

315

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

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

318 codec->pix_fmt = AV_PIX_FMT_YUV420P;

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

320 codec->pix_fmt = AV_PIX_FMT_YUV422P;

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

322 codec->pix_fmt = AV_PIX_FMT_YUV444P;

323 } else {

324 av_log(codec, AV_LOG_ERROR,

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

326 return AVERROR_INVALIDDATA;

327 }

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

329 /* This is an integer between 1 and 1048561

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

331 codec->width = atoi(value);

332 return 0;

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

334 /* This is an integer between 1 and 1048561

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

336 codec->height = atoi(value);

337 return 0;

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

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

340 return AVERROR_PATCHWELCOME;

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

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

343 *--after the delivery-method tag

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

345 return AVERROR_PATCHWELCOME;

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

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

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

349 uint8_t *decoded_packet = NULL;

350 int packet_size;

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

352

353 if (decoded_alloc <= INT_MAX) {

354 decoded_packet = av_malloc(decoded_alloc);

355 if (decoded_packet) {

356 packet_size =

357 av_base64_decode(decoded_packet, value, decoded_alloc);

358

359 result = parse_packed_headers

360 (decoded_packet, decoded_packet + packet_size, codec,

361 xiph_data);

362 } else {

363 av_log(codec, AV_LOG_ERROR,

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

365 result = AVERROR(ENOMEM);

366 }

367 } else {

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

369 result = AVERROR_INVALIDDATA;

370 }

371 av_free(decoded_packet);

372 }

373 return result;

374 }

375

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

377 PayloadContext *data, const char *line)

378 {

379 const char *p;

380

381 if (st_index < 0)

382 return 0;

383

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

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

386 xiph_parse_fmtp_pair);

387 }

388

389 return 0;

390 }

391

392 RTPDynamicProtocolHandler ff_theora_dynamic_handler = {

393 .enc_name = "theora",

394 .codec_type = AVMEDIA_TYPE_VIDEO,

395 .codec_id = AV_CODEC_ID_THEORA,

396 .parse_sdp_a_line = xiph_parse_sdp_line,

397 .alloc = xiph_new_context,

398 .free = xiph_free_context,

399 .parse_packet = xiph_handle_packet

400 };

401

402 RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {

403 .enc_name = "vorbis",

404 .codec_type = AVMEDIA_TYPE_AUDIO,

405 .codec_id = AV_CODEC_ID_VORBIS,

406 .init = xiph_vorbis_init,

407 .parse_sdp_a_line = xiph_parse_sdp_line,

408 .alloc = xiph_new_context,

409 .free = xiph_free_context,

410 .parse_packet = xiph_handle_packet

411 };

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