FFmpeg: libavformat/rtpdec_jpeg.c Source File

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libavformat

rtpdec_jpeg.c

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1 /*

2 * RTP JPEG-compressed Video Depacketizer, RFC 2435

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 #include "avformat.h"

23 #include "rtpdec.h"

24 #include "rtpdec_formats.h"

25 #include "libavutil/intreadwrite.h"

26 #include "libavcodec/mjpeg.h"

27 #include "libavcodec/bytestream.h"

29 /**

30 * RTP/JPEG specific private data.

31 */

32 struct PayloadContext {

33 AVIOContext *frame; ///< current frame buffer

34 uint32_t timestamp; ///< current frame timestamp

35 int hdr_size; ///< size of the current frame header

36 uint8_t qtables[128][128];

37 uint8_t qtables_len[128];

38 };

40 static const uint8_t default_quantizers[128] = {

41 /* luma table */

42 16, 11, 12, 14, 12, 10, 16, 14,

43 13, 14, 18, 17, 16, 19, 24, 40,

44 26, 24, 22, 22, 24, 49, 35, 37,

45 29, 40, 58, 51, 61, 60, 57, 51,

46 56, 55, 64, 72, 92, 78, 64, 68,

47 87, 69, 55, 56, 80, 109, 81, 87,

48 95, 98, 103, 104, 103, 62, 77, 113,

49 121, 112, 100, 120, 92, 101, 103, 99,

51 /* chroma table */

52 17, 18, 18, 24, 21, 24, 47, 26,

53 26, 47, 99, 66, 56, 66, 99, 99,

54 99, 99, 99, 99, 99, 99, 99, 99,

55 99, 99, 99, 99, 99, 99, 99, 99,

56 99, 99, 99, 99, 99, 99, 99, 99,

57 99, 99, 99, 99, 99, 99, 99, 99,

58 99, 99, 99, 99, 99, 99, 99, 99,

59 99, 99, 99, 99, 99, 99, 99, 99

60 };

62 static PayloadContext *jpeg_new_context(void)

63 {

64 return av_mallocz(sizeof(PayloadContext));

65 }

67 static inline void free_frame_if_needed(PayloadContext *jpeg)

68 {

69 if (jpeg->frame) {

70 uint8_t *p;

71 avio_close_dyn_buf(jpeg->frame, &p);

72 av_free(p);

73 jpeg->frame = NULL;

74 }

75 }

77 static void jpeg_free_context(PayloadContext *jpeg)

78 {

79 free_frame_if_needed(jpeg);

80 av_free(jpeg);

81 }

83 static int jpeg_create_huffman_table(PutByteContext *p, int table_class,

84 int table_id, const uint8_t *bits_table,

85 const uint8_t *value_table)

86 {

87 int i, n = 0;

89 bytestream2_put_byte(p, table_class << 4 | table_id);

91 for (i = 1; i <= 16; i++) {

92 n += bits_table[i];

93 bytestream2_put_byte(p, bits_table[i]);

94 }

96 for (i = 0; i < n; i++) {

97 bytestream2_put_byte(p, value_table[i]);

98 }

99 return n + 17;

100 }

101

102 static void jpeg_put_marker(PutByteContext *pbc, int code)

103 {

104 bytestream2_put_byte(pbc, 0xff);

105 bytestream2_put_byte(pbc, code);

106 }

107

108 static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,

109 uint32_t h, const uint8_t *qtable, int nb_qtable)

110 {

111 PutByteContext pbc;

112 uint8_t *dht_size_ptr;

113 int dht_size, i;

114

115 bytestream2_init_writer(&pbc, buf, size);

116

117 /* Convert from blocks to pixels. */

118 w <<= 3;

119 h <<= 3;

120

121 /* SOI */

122 jpeg_put_marker(&pbc, SOI);

123

124 /* JFIF header */

125 jpeg_put_marker(&pbc, APP0);

126 bytestream2_put_be16(&pbc, 16);

127 bytestream2_put_buffer(&pbc, "JFIF", 5);

128 bytestream2_put_be16(&pbc, 0x0201);

129 bytestream2_put_byte(&pbc, 0);

130 bytestream2_put_be16(&pbc, 1);

131 bytestream2_put_be16(&pbc, 1);

132 bytestream2_put_byte(&pbc, 0);

133 bytestream2_put_byte(&pbc, 0);

134

135 /* DQT */

136 jpeg_put_marker(&pbc, DQT);

137 bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));

138

139 for (i = 0; i < nb_qtable; i++) {

140 bytestream2_put_byte(&pbc, i);

141

142 /* Each table is an array of 64 values given in zig-zag

143 * order, identical to the format used in a JFIF DQT

144 * marker segment. */

145 bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);

146 }

147

148 /* DHT */

149 jpeg_put_marker(&pbc, DHT);

150 dht_size_ptr = pbc.buffer;

151 bytestream2_put_be16(&pbc, 0);

152

153 dht_size = 2;

154 dht_size += jpeg_create_huffman_table(&pbc, 0, 0,avpriv_mjpeg_bits_dc_luminance,

155 avpriv_mjpeg_val_dc);

156 dht_size += jpeg_create_huffman_table(&pbc, 0, 1, avpriv_mjpeg_bits_dc_chrominance,

157 avpriv_mjpeg_val_dc);

158 dht_size += jpeg_create_huffman_table(&pbc, 1, 0, avpriv_mjpeg_bits_ac_luminance,

159 avpriv_mjpeg_val_ac_luminance);

160 dht_size += jpeg_create_huffman_table(&pbc, 1, 1, avpriv_mjpeg_bits_ac_chrominance,

161 avpriv_mjpeg_val_ac_chrominance);

162 AV_WB16(dht_size_ptr, dht_size);

163

164 /* SOF0 */

165 jpeg_put_marker(&pbc, SOF0);

166 bytestream2_put_be16(&pbc, 17); /* size */

167 bytestream2_put_byte(&pbc, 8); /* bits per component */

168 bytestream2_put_be16(&pbc, h);

169 bytestream2_put_be16(&pbc, w);

170 bytestream2_put_byte(&pbc, 3); /* number of components */

171 bytestream2_put_byte(&pbc, 1); /* component number */

172 bytestream2_put_byte(&pbc, (2 << 4) | (type ? 2 : 1)); /* hsample/vsample */

173 bytestream2_put_byte(&pbc, 0); /* matrix number */

174 bytestream2_put_byte(&pbc, 2); /* component number */

175 bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */

176 bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */

177 bytestream2_put_byte(&pbc, 3); /* component number */

178 bytestream2_put_byte(&pbc, 1 << 4 | 1); /* hsample/vsample */

179 bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0); /* matrix number */

180

181 /* SOS */

182 jpeg_put_marker(&pbc, SOS);

183 bytestream2_put_be16(&pbc, 12);

184 bytestream2_put_byte(&pbc, 3);

185 bytestream2_put_byte(&pbc, 1);

186 bytestream2_put_byte(&pbc, 0);

187 bytestream2_put_byte(&pbc, 2);

188 bytestream2_put_byte(&pbc, 17);

189 bytestream2_put_byte(&pbc, 3);

190 bytestream2_put_byte(&pbc, 17);

191 bytestream2_put_byte(&pbc, 0);

192 bytestream2_put_byte(&pbc, 63);

193 bytestream2_put_byte(&pbc, 0);

194

195 /* Return the length in bytes of the JPEG header. */

196 return bytestream2_tell_p(&pbc);

197 }

198

199 static void create_default_qtables(uint8_t *qtables, uint8_t q)

200 {

201 int factor = q;

202 int i;

203

204 factor = av_clip(q, 1, 99);

205

206 if (q < 50)

207 q = 5000 / factor;

208 else

209 q = 200 - factor * 2;

210

211 for (i = 0; i < 128; i++) {

212 int val = (default_quantizers[i] * q + 50) / 100;

213

214 /* Limit the quantizers to 1 <= q <= 255. */

215 val = av_clip(val, 1, 255);

216 qtables[i] = val;

217 }

218 }

219

220 static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,

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

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

223 int flags)

224 {

225 uint8_t type, q, width, height;

226 const uint8_t *qtables = NULL;

227 uint16_t qtable_len;

228 uint32_t off;

229 int ret;

230

231 if (len < 8) {

232 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");

233 return AVERROR_INVALIDDATA;

234 }

235

236 /* Parse the main JPEG header. */

237 off = AV_RB24(buf + 1); /* fragment byte offset */

238 type = AV_RB8(buf + 4); /* id of jpeg decoder params */

239 q = AV_RB8(buf + 5); /* quantization factor (or table id) */

240 width = AV_RB8(buf + 6); /* frame width in 8 pixel blocks */

241 height = AV_RB8(buf + 7); /* frame height in 8 pixel blocks */

242 buf += 8;

243 len -= 8;

244

245 /* Parse the restart marker header. */

246 if (type > 63) {

247 av_log(ctx, AV_LOG_ERROR,

248 "Unimplemented RTP/JPEG restart marker header.\n");

249 return AVERROR_PATCHWELCOME;

250 }

251 if (type > 1) {

252 av_log(ctx, AV_LOG_ERROR, "Unimplemented RTP/JPEG type %d\n", type);

253 return AVERROR_PATCHWELCOME;

254 }

255

256 /* Parse the quantization table header. */

257 if (off == 0) {

258 /* Start of JPEG data packet. */

259 uint8_t new_qtables[128];

260 uint8_t hdr[1024];

261

262 if (q > 127) {

263 uint8_t precision;

264 if (len < 4) {

265 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");

266 return AVERROR_INVALIDDATA;

267 }

268

269 /* The first byte is reserved for future use. */

270 precision = AV_RB8(buf + 1); /* size of coefficients */

271 qtable_len = AV_RB16(buf + 2); /* length in bytes */

272 buf += 4;

273 len -= 4;

274

275 if (precision)

276 av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");

277

278 if (qtable_len > 0) {

279 if (len < qtable_len) {

280 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");

281 return AVERROR_INVALIDDATA;

282 }

283 qtables = buf;

284 buf += qtable_len;

285 len -= qtable_len;

286 if (q < 255) {

287 if (jpeg->qtables_len[q - 128] &&

288 (jpeg->qtables_len[q - 128] != qtable_len ||

289 memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {

290 av_log(ctx, AV_LOG_WARNING,

291 "Quantization tables for q=%d changed\n", q);

292 } else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {

293 memcpy(&jpeg->qtables[q - 128][0], qtables,

294 qtable_len);

295 jpeg->qtables_len[q - 128] = qtable_len;

296 }

297 }

298 } else {

299 if (q == 255) {

300 av_log(ctx, AV_LOG_ERROR,

301 "Invalid RTP/JPEG packet. Quantization tables not found.\n");

302 return AVERROR_INVALIDDATA;

303 }

304 if (!jpeg->qtables_len[q - 128]) {

305 av_log(ctx, AV_LOG_ERROR,

306 "No quantization tables known for q=%d yet.\n", q);

307 return AVERROR_INVALIDDATA;

308 }

309 qtables = &jpeg->qtables[q - 128][0];

310 qtable_len = jpeg->qtables_len[q - 128];

311 }

312 } else { /* q <= 127 */

313 if (q == 0 || q > 99) {

314 av_log(ctx, AV_LOG_ERROR, "Reserved q value %d\n", q);

315 return AVERROR_INVALIDDATA;

316 }

317 create_default_qtables(new_qtables, q);

318 qtables = new_qtables;

319 qtable_len = sizeof(new_qtables);

320 }

321

322 /* Skip the current frame in case of the end packet

323 * has been lost somewhere. */

324 free_frame_if_needed(jpeg);

325

326 if ((ret = avio_open_dyn_buf(&jpeg->frame)) < 0)

327 return ret;

328 jpeg->timestamp = *timestamp;

329

330 /* Generate a frame and scan headers that can be prepended to the

331 * RTP/JPEG data payload to produce a JPEG compressed image in

332 * interchange format. */

333 jpeg->hdr_size = jpeg_create_header(hdr, sizeof(hdr), type, width,

334 height, qtables,

335 qtable_len / 64);

336

337 /* Copy JPEG header to frame buffer. */

338 avio_write(jpeg->frame, hdr, jpeg->hdr_size);

339 }

340

341 if (!jpeg->frame) {

342 av_log(ctx, AV_LOG_ERROR,

343 "Received packet without a start chunk; dropping frame.\n");

344 return AVERROR(EAGAIN);

345 }

346

347 if (jpeg->timestamp != *timestamp) {

348 /* Skip the current frame if timestamp is incorrect.

349 * A start packet has been lost somewhere. */

350 free_frame_if_needed(jpeg);

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

352 return AVERROR_INVALIDDATA;

353 }

354

355 if (off != avio_tell(jpeg->frame) - jpeg->hdr_size) {

356 av_log(ctx, AV_LOG_ERROR,

357 "Missing packets; dropping frame.\n");

358 return AVERROR(EAGAIN);

359 }

360

361 /* Copy data to frame buffer. */

362 avio_write(jpeg->frame, buf, len);

363

364 if (flags & RTP_FLAG_MARKER) {

365 /* End of JPEG data packet. */

366 uint8_t buf[2] = { 0xff, EOI };

367

368 /* Put EOI marker. */

369 avio_write(jpeg->frame, buf, sizeof(buf));

370

371 /* Prepare the JPEG packet. */

372 if ((ret = ff_rtp_finalize_packet(pkt, &jpeg->frame, st->index)) < 0) {

373 av_log(ctx, AV_LOG_ERROR,

374 "Error occurred when getting frame buffer.\n");

375 return ret;

376 }

377

378 return 0;

379 }

380

381 return AVERROR(EAGAIN);

382 }

383

384 RTPDynamicProtocolHandler ff_jpeg_dynamic_handler = {

385 .enc_name = "JPEG",

386 .codec_type = AVMEDIA_TYPE_VIDEO,

387 .codec_id = AV_CODEC_ID_MJPEG,

388 .alloc = jpeg_new_context,

389 .free = jpeg_free_context,

390 .parse_packet = jpeg_parse_packet,

391 .static_payload_id = 26,

392 };

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