FFmpeg: libavformat/rtpdec_xiph.c Source File

FFmpeg

[フレーム]

libavformat

rtpdec_xiph.c

Go to the documentation of this file.

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 "rtpdec.h"

37 #include "rtpdec_formats.h"

39 /**

40 * RTP/Xiph specific private data.

41 */

42 struct PayloadContext {

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

44 uint32_t timestamp;

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

46 uint8_t *split_buf;

47 int split_pos, split_buf_len, split_buf_size;

48 int split_pkts;

49 };

51 static PayloadContext *xiph_new_context(void)

52 {

53 return av_mallocz(sizeof(PayloadContext));

54 }

56 static inline void free_fragment_if_needed(PayloadContext * data)

57 {

58 if (data->fragment) {

59 uint8_t* p;

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

61 av_free(p);

62 data->fragment = NULL;

63 }

64 }

66 static void xiph_free_context(PayloadContext * data)

67 {

68 free_fragment_if_needed(data);

69 av_free(data->split_buf);

70 av_free(data);

71 }

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

74 PayloadContext *data)

75 {

76 if (st_index < 0)

77 return 0;

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

79 return 0;

80 }

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

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

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

86 int flags)

87 {

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

91 if (!buf) {

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

93 data->split_pkts <= 0) {

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

95 return AVERROR_INVALIDDATA;

96 }

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

98 data->split_pos += 2;

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

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

101 return AVERROR_INVALIDDATA;

102 }

103 if (av_new_packet(pkt, pkt_len)) {

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

105 return AVERROR(ENOMEM);

106 }

107 pkt->stream_index = st->index;

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

109 data->split_pos += pkt_len;

110 data->split_pkts--;

111 return data->split_pkts > 0;

112 }

113

114 if (len < 6) {

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

116 return AVERROR_INVALIDDATA;

117 }

118

119 // read xiph rtp headers

120 ident = AV_RB24(buf);

121 fragmented = buf[3] >> 6;

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

123 num_pkts = buf[3] & 0xf;

124 pkt_len = AV_RB16(buf + 4);

125

126 if (pkt_len > len - 6) {

127 av_log(ctx, AV_LOG_ERROR,

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

129 len);

130 return AVERROR_INVALIDDATA;

131 }

132

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

134 av_log(ctx, AV_LOG_ERROR,

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

136 return AVERROR_PATCHWELCOME;

137 }

138

139 if (tdt) {

140 av_log(ctx, AV_LOG_ERROR,

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

142 fragmented, tdt, num_pkts);

143 return AVERROR_PATCHWELCOME;

144 }

145

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

147 len -= 6;

148

149 if (fragmented == 0) {

150 if (av_new_packet(pkt, pkt_len)) {

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

152 return AVERROR(ENOMEM);

153 }

154 pkt->stream_index = st->index;

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

156 buf += pkt_len;

157 len -= pkt_len;

158 num_pkts--;

159

160 if (num_pkts > 0) {

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

162 av_freep(&data->split_buf);

163 data->split_buf_size = 2 * len;

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

165 if (!data->split_buf) {

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

167 av_free_packet(pkt);

168 return AVERROR(ENOMEM);

169 }

170 }

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

172 data->split_buf_len = len;

173 data->split_pos = 0;

174 data->split_pkts = num_pkts;

175 return 1;

176 }

177

178 return 0;

179

180 } else if (fragmented == 1) {

181 // start of xiph data fragment

182 int res;

183

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

185 free_fragment_if_needed(data);

186

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

188 return res;

189

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

191 data->timestamp = *timestamp;

192

193 } else {

194 av_assert1(fragmented < 4);

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

196 // skip if fragmented timestamp is incorrect;

197 // a start packet has been lost somewhere

198 free_fragment_if_needed(data);

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

200 return AVERROR_INVALIDDATA;

201 }

202 if (!data->fragment) {

203 av_log(ctx, AV_LOG_WARNING,

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

205 return AVERROR(EAGAIN);

206 }

207

208 // copy data to fragment buffer

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

210

211 if (fragmented == 3) {

212 // end of xiph data packet

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

214 if (ret < 0) {

215 av_log(ctx, AV_LOG_ERROR,

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

217 return ret;

218 }

219

220 return 0;

221 }

222 }

223

224 return AVERROR(EAGAIN);

225 }

226

227 /**

228 * Length encoding described in RFC5215 section 3.1.1.

229 */

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

231 {

232 int n = 0;

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

234 n <<= 7;

235 n += **buf & 0x7f;

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

237 ++*buf;

238 return n;

239 }

240 }

241 return 0;

242 }

243

244 /**

245 * Based off parse_packed_headers in Vorbis RTP

246 */

247 static int

248 parse_packed_headers(const uint8_t * packed_headers,

249 const uint8_t * packed_headers_end,

250 AVCodecContext * codec, PayloadContext * xiph_data)

251 {

252

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

254 uint8_t *ptr;

255

256 if (packed_headers_end - packed_headers < 9) {

257 av_log(codec, AV_LOG_ERROR,

258 "Invalid %td byte packed header.",

259 packed_headers_end - packed_headers);

260 return AVERROR_INVALIDDATA;

261 }

262

263 num_packed = bytestream_get_be32(&packed_headers);

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

265 length = bytestream_get_be16(&packed_headers);

266 num_headers = get_base128(&packed_headers, packed_headers_end);

267 length1 = get_base128(&packed_headers, packed_headers_end);

268 length2 = get_base128(&packed_headers, packed_headers_end);

269

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

271 av_log(codec, AV_LOG_ERROR,

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

273 num_packed, num_headers);

274 return AVERROR_PATCHWELCOME;

275 }

276

277 if (packed_headers_end - packed_headers != length ||

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

279 av_log(codec, AV_LOG_ERROR,

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

281 length2, packed_headers_end - packed_headers, length);

282 return AVERROR_INVALIDDATA;

283 }

284

285 /* allocate extra space:

286 * -- length/255 +2 for xiphlacing

287 * -- one for the '2' marker

288 * -- FF_INPUT_BUFFER_PADDING_SIZE required */

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

290

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

292 if (!ptr) {

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

294 return AVERROR(ENOMEM);

295 }

296 *ptr++ = 2;

297 ptr += av_xiphlacing(ptr, length1);

298 ptr += av_xiphlacing(ptr, length2);

299 memcpy(ptr, packed_headers, length);

300 ptr += length;

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

302 // clear out remaining parts of the buffer

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

304

305 return 0;

306 }

307

308 static int xiph_parse_fmtp_pair(AVStream* stream,

309 PayloadContext *xiph_data,

310 char *attr, char *value)

311 {

312 AVCodecContext *codec = stream->codec;

313 int result = 0;

314

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

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

317 codec->pix_fmt = AV_PIX_FMT_YUV420P;

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

319 codec->pix_fmt = AV_PIX_FMT_YUV422P;

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

321 codec->pix_fmt = AV_PIX_FMT_YUV444P;

322 } else {

323 av_log(codec, AV_LOG_ERROR,

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

325 return AVERROR_INVALIDDATA;

326 }

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

328 /* This is an integer between 1 and 1048561

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

330 codec->width = atoi(value);

331 return 0;

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

333 /* This is an integer between 1 and 1048561

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

335 codec->height = atoi(value);

336 return 0;

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

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

339 return AVERROR_PATCHWELCOME;

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

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

342 *--after the delivery-method tag

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

344 return AVERROR_PATCHWELCOME;

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

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

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

348 uint8_t *decoded_packet = NULL;

349 int packet_size;

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

351

352 if (decoded_alloc <= INT_MAX) {

353 decoded_packet = av_malloc(decoded_alloc);

354 if (decoded_packet) {

355 packet_size =

356 av_base64_decode(decoded_packet, value, decoded_alloc);

357

358 result = parse_packed_headers

359 (decoded_packet, decoded_packet + packet_size, codec,

360 xiph_data);

361 } else {

362 av_log(codec, AV_LOG_ERROR,

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

364 result = AVERROR(ENOMEM);

365 }

366 } else {

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

368 result = AVERROR_INVALIDDATA;

369 }

370 av_free(decoded_packet);

371 }

372 return result;

373 }

374

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

376 PayloadContext *data, const char *line)

377 {

378 const char *p;

379

380 if (st_index < 0)

381 return 0;

382

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

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

385 xiph_parse_fmtp_pair);

386 }

387

388 return 0;

389 }

390

391 RTPDynamicProtocolHandler ff_theora_dynamic_handler = {

392 .enc_name = "theora",

393 .codec_type = AVMEDIA_TYPE_VIDEO,

394 .codec_id = AV_CODEC_ID_THEORA,

395 .parse_sdp_a_line = xiph_parse_sdp_line,

396 .alloc = xiph_new_context,

397 .free = xiph_free_context,

398 .parse_packet = xiph_handle_packet

399 };

400

401 RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {

402 .enc_name = "vorbis",

403 .codec_type = AVMEDIA_TYPE_AUDIO,

404 .codec_id = AV_CODEC_ID_VORBIS,

405 .init = xiph_vorbis_init,

406 .parse_sdp_a_line = xiph_parse_sdp_line,

407 .alloc = xiph_new_context,

408 .free = xiph_free_context,

409 .parse_packet = xiph_handle_packet

410 };

Generated on Wed Jul 10 2013 23:48:14 for FFmpeg by doxygen 1.8.2