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1/*
2 * Pro-MPEG Code of Practice #3 Release 2 FEC
3 * Copyright (c) 2016 Mobibase, France (http://www.mobibase.com)
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 */
21
22/**
23 * @file
24 * Pro-MPEG Code of Practice #3 Release 2 FEC protocol
25 * @author Vlad Tarca <vlad.tarca@gmail.com>
26 */
27
28/*
29 * Reminder:
30
31 [RFC 2733] FEC Packet Structure
32
33 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
34 | RTP Header |
35 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 | FEC Header |
37 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 | FEC Payload |
39 | |
40 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41
42
43 [RFC 3550] RTP header
44
45 0 1 2 3
46 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
47 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 |V=2|P|X| CC |M| PT | sequence number |
49 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
50 | timestamp |
51 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
52 | synchronization source (SSRC) identifier |
53 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
54 | contributing source (CSRC) identifiers |
55 | .... |
56 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
57
58 [RFC 3550] RTP header extension (after CSRC)
59
60 0 1 2 3
61 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
62 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
63 | defined by profile | length |
64 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
65 | header extension |
66 | .... |
67 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
68
69 [Pro-MPEG COP3] FEC Header
70
71 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72 | SNBase low bits | length recovery |
73 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
74 |E| PT recovery | mask |
75 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
76 | TS recovery |
77 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
78 |X|D|type |index| offset | NA |SNBase ext bits|
79 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
80
81 */
82
83#include "libavutil/avstring.h"
84#include "libavutil/intreadwrite.h"
85#include "libavutil/opt.h"
86#include "libavutil/parseutils.h"
87#include "libavutil/random_seed.h"
88#include "avformat.h"
89#include "config.h"
90#include "url.h"
91
92#define PROMPEG_RTP_PT 0x60
93#define PROMPEG_FEC_COL 0x0
94#define PROMPEG_FEC_ROW 0x1
95
96typedef struct PrompegFec {
97 uint16_t sn;
98 uint32_t ts;
99 uint8_t *bitstring;
100} PrompegFec;
101
102typedef struct PrompegContext {
103 const AVClass *class;
104 URLContext *fec_col_hd, *fec_row_hd;
105 PrompegFec **fec_arr, **fec_col_tmp, **fec_col, *fec_row;
106 int ttl;
107 uint8_t l, d;
108 uint8_t *rtp_buf;
109 uint16_t rtp_col_sn, rtp_row_sn;
110 uint16_t length_recovery;
111 int packet_size;
112 int packet_idx, packet_idx_max;
113 int fec_arr_len;
114 int bitstring_size;
115 int rtp_buf_size;
116 int init;
117 int first;
118} PrompegContext;
119
120#define OFFSET(x) offsetof(PrompegContext, x)
121#define E AV_OPT_FLAG_ENCODING_PARAM
122
123static const AVOption options[] = {
124 { "ttl", "Time to live (in milliseconds, multicast only)", OFFSET(ttl), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, .flags = E },
125 { "l", "FEC L", OFFSET(l), AV_OPT_TYPE_INT, { .i64 = 5 }, 4, 20, .flags = E },
126 { "d", "FEC D", OFFSET(d), AV_OPT_TYPE_INT, { .i64 = 5 }, 4, 20, .flags = E },
127 { NULL }
128};
129
130static const AVClass prompeg_class = {
131 .class_name = "prompeg",
132 .item_name = av_default_item_name,
133 .option = options,
134 .version = LIBAVUTIL_VERSION_INT,
135};
136
137static void xor_fast(const uint8_t *in1, const uint8_t *in2, uint8_t *out, int size) {
138 int i, n, s;
139
140#if HAVE_FAST_64BIT
141 uint64_t v1, v2;
142
143 n = size / sizeof (uint64_t);
144 s = n * sizeof (uint64_t);
145
146 for (i = 0; i < n; i++) {
147 v1 = AV_RN64A(in1);
148 v2 = AV_RN64A(in2);
149 AV_WN64A(out, v1 ^ v2);
150 in1 += 8;
151 in2 += 8;
152 out += 8;
153 }
154#else
155 uint32_t v1, v2;
156
157 n = size / sizeof (uint32_t);
158 s = n * sizeof (uint32_t);
159
160 for (i = 0; i < n; i++) {
161 v1 = AV_RN32A(in1);
162 v2 = AV_RN32A(in2);
163 AV_WN32A(out, v1 ^ v2);
164 in1 += 4;
165 in2 += 4;
166 out += 4;
167 }
168#endif
169
170 n = size - s;
171
172 for (i = 0; i < n; i++) {
173 out[i] = in1[i] ^ in2[i];
174 }
175}
176
177static int prompeg_create_bitstring(URLContext *h, const uint8_t *buf, int size,
178 uint8_t **bitstring) {
179 PrompegContext *s = h->priv_data;
180 uint8_t *b;
181
182 if (size < 12 || (buf[0] & 0xc0) != 0x80 || (buf[1] & 0x7f) != 0x21) {
183 av_log(h, AV_LOG_ERROR, "Unsupported stream format (expected MPEG-TS over RTP)\n");
184 return AVERROR(EINVAL);
185 }
186 if (size != s->packet_size) {
187 av_log(h, AV_LOG_ERROR, "The RTP packet size must be constant (set pkt_size)\n");
188 return AVERROR(EINVAL);
189 }
190
191 *bitstring = av_malloc(s->bitstring_size);
192 if (!*bitstring) {
193 av_log(h, AV_LOG_ERROR, "Failed to allocate the bitstring buffer\n");
194 return AVERROR(ENOMEM);
195 }
196 b = *bitstring;
197
198 // P, X, CC
199 b[0] = buf[0] & 0x3f;
200 // M, PT
201 b[1] = buf[1];
202 // Timestamp
203 b[2] = buf[4];
204 b[3] = buf[5];
205 b[4] = buf[6];
206 b[5] = buf[7];
207 /*
208 * length_recovery: the unsigned network-ordered sum of lengths of CSRC,
209 * padding, extension and media payload
210 */
211 AV_WB16(b + 6, s->length_recovery);
212 // Payload
213 memcpy(b + 8, buf + 12, s->length_recovery);
214
215 return 0;
216}
217
218static int prompeg_write_fec(URLContext *h, PrompegFec *fec, uint8_t type) {
219 PrompegContext *s = h->priv_data;
220 URLContext *hd;
221 uint8_t *buf = s->rtp_buf; // zero-filled
222 uint8_t *b = fec->bitstring;
223 uint16_t sn;
224 int ret;
225
226 sn = type == PROMPEG_FEC_COL ? ++s->rtp_col_sn : ++s->rtp_row_sn;
227
228 // V, P, X, CC
229 buf[0] = 0x80 | (b[0] & 0x3f);
230 // M, PT
231 buf[1] = (b[1] & 0x80) | PROMPEG_RTP_PT;
232 // SN
233 AV_WB16(buf + 2, sn);
234 // TS
235 AV_WB32(buf + 4, fec->ts);
236 // CSRC=0
237 //AV_WB32(buf + 8, 0);
238 // SNBase low bits
239 AV_WB16(buf + 12, fec->sn);
240 // Length recovery
241 buf[14] = b[6];
242 buf[15] = b[7];
243 // E=1, PT recovery
244 buf[16] = 0x80 | b[1];
245 // Mask=0
246 //buf[17] = 0x0;
247 //buf[18] = 0x0;
248 //buf[19] = 0x0;
249 // TS recovery
250 buf[20] = b[2];
251 buf[21] = b[3];
252 buf[22] = b[4];
253 buf[23] = b[5];
254 // X=0, D, type=0, index=0
255 buf[24] = type == PROMPEG_FEC_COL ? 0x0 : 0x40;
256 // offset
257 buf[25] = type == PROMPEG_FEC_COL ? s->l : 0x1;
258 // NA
259 buf[26] = type == PROMPEG_FEC_COL ? s->d : s->l;
260 // SNBase ext bits=0
261 //buf[27] = 0x0;
262 // Payload
263 memcpy(buf + 28, b + 8, s->length_recovery);
264
265 hd = type == PROMPEG_FEC_COL ? s->fec_col_hd : s->fec_row_hd;
266 ret = ffurl_write(hd, buf, s->rtp_buf_size);
267 return ret;
268}
269
270static int prompeg_open(URLContext *h, const char *uri, int flags) {
271 PrompegContext *s = h->priv_data;
272 AVDictionary *udp_opts = NULL;
273 int rtp_port;
274 char hostname[256];
275 char buf[1024];
276
277 s->fec_col_hd = NULL;
278 s->fec_row_hd = NULL;
279
280 if (s->l * s->d > 100) {
281 av_log(h, AV_LOG_ERROR, "L * D must be <= 100\n");
282 return AVERROR(EINVAL);
283 }
284
285 av_url_split(NULL, 0, NULL, 0, hostname, sizeof (hostname), &rtp_port,
286 NULL, 0, uri);
287
288 if (rtp_port < 1 || rtp_port > UINT16_MAX - 4) {
289 av_log(h, AV_LOG_ERROR, "Invalid RTP base port %d\n", rtp_port);
290 return AVERROR(EINVAL);
291 }
292
293 if (s->ttl > 0) {
294 snprintf(buf, sizeof (buf), "%d", s->ttl);
295 av_dict_set(&udp_opts, "ttl", buf, 0);
296 }
297
298 ff_url_join(buf, sizeof (buf), "udp", NULL, hostname, rtp_port + 2, NULL);
299 if (ffurl_open_whitelist(&s->fec_col_hd, buf, flags, &h->interrupt_callback,
300 &udp_opts, h->protocol_whitelist, h->protocol_blacklist, h) < 0)
301 goto fail;
302 ff_url_join(buf, sizeof (buf), "udp", NULL, hostname, rtp_port + 4, NULL);
303 if (ffurl_open_whitelist(&s->fec_row_hd, buf, flags, &h->interrupt_callback,
304 &udp_opts, h->protocol_whitelist, h->protocol_blacklist, h) < 0)
305 goto fail;
306
307 h->max_packet_size = s->fec_col_hd->max_packet_size;
308 s->init = 1;
309
310 av_dict_free(&udp_opts);
311 av_log(h, AV_LOG_INFO, "ProMPEG CoP#3-R2 FEC L=%d D=%d\n", s->l, s->d);
312 return 0;
313
314fail:
315 ffurl_closep(&s->fec_col_hd);
316 ffurl_closep(&s->fec_row_hd);
317 av_dict_free(&udp_opts);
318 return AVERROR(EIO);
319}
320
321static int prompeg_init(URLContext *h, const uint8_t *buf, int size) {
322 PrompegContext *s = h->priv_data;
323 uint32_t seed;
324 int i;
325
326 s->fec_arr = NULL;
327 s->rtp_buf = NULL;
328
329 if (size < 12 || size > UINT16_MAX + 12) {
330 av_log(h, AV_LOG_ERROR, "Invalid RTP packet size\n");
331 return AVERROR_INVALIDDATA;
332 }
333
334 s->packet_idx = 0;
335 s->packet_idx_max = s->l * s->d;
336 s->packet_size = size;
337 s->length_recovery = size - 12;
338 s->rtp_buf_size = 28 + s->length_recovery; // 12 + 16: RTP + FEC headers
339 s->bitstring_size = 8 + s->length_recovery; // 8: P, X, CC, M, PT, SN, TS
340 s->fec_arr_len = 1 + 2 * s->l; // row + column tmp + column out
341
342 if (h->flags & AVFMT_FLAG_BITEXACT) {
343 s->rtp_col_sn = 0;
344 s->rtp_row_sn = 0;
345 } else {
346 seed = av_get_random_seed();
347 s->rtp_col_sn = seed & 0x0fff;
348 s->rtp_row_sn = (seed >> 16) & 0x0fff;
349 }
350
351 s->fec_arr = av_malloc_array(s->fec_arr_len, sizeof (PrompegFec*));
352 if (!s->fec_arr) {
353 goto fail;
354 }
355 for (i = 0; i < s->fec_arr_len; i++) {
356 s->fec_arr[i] = av_malloc(sizeof (PrompegFec));
357 if (!s->fec_arr[i]) {
358 goto fail;
359 }
360 s->fec_arr[i]->bitstring = av_malloc_array(s->bitstring_size, sizeof (uint8_t));
361 if (!s->fec_arr[i]->bitstring) {
362 av_freep(&s->fec_arr[i]);
363 goto fail;
364 }
365 }
366 s->fec_row = *s->fec_arr;
367 s->fec_col = s->fec_arr + 1;
368 s->fec_col_tmp = s->fec_arr + 1 + s->l;
369
370 s->rtp_buf = av_malloc_array(s->rtp_buf_size, sizeof (uint8_t));
371 if (!s->rtp_buf) {
372 goto fail;
373 }
374 memset(s->rtp_buf, 0, s->rtp_buf_size);
375
376 s->init = 0;
377 s->first = 1;
378
379 return 0;
380
381fail:
382 av_log(h, AV_LOG_ERROR, "Failed to allocate the FEC buffer\n");
383 return AVERROR(ENOMEM);
384}
385
386static int prompeg_write(URLContext *h, const uint8_t *buf, int size) {
387 PrompegContext *s = h->priv_data;
388 PrompegFec *fec_tmp;
389 uint8_t *bitstring = NULL;
390 int col_idx, col_out_idx, row_idx;
391 int ret, written = 0;
392
393 if (s->init && ((ret = prompeg_init(h, buf, size)) < 0))
394 goto end;
395
396 if ((ret = prompeg_create_bitstring(h, buf, size, &bitstring)) < 0)
397 goto end;
398
399 col_idx = s->packet_idx % s->l;
400 row_idx = s->packet_idx / s->l % s->d;
401
402 // FEC' (row) send block-aligned, xor
403 if (col_idx == 0) {
404 if (!s->first || s->packet_idx > 0) {
405 if ((ret = prompeg_write_fec(h, s->fec_row, PROMPEG_FEC_ROW)) < 0)
406 goto end;
407 written += ret;
408 }
409 memcpy(s->fec_row->bitstring, bitstring, s->bitstring_size);
410 s->fec_row->sn = AV_RB16(buf + 2);
411 s->fec_row->ts = AV_RB32(buf + 4);
412 } else {
413 xor_fast(s->fec_row->bitstring, bitstring, s->fec_row->bitstring,
414 s->bitstring_size);
415 }
416
417 // FEC (column) xor
418 if (row_idx == 0) {
419 if (!s->first) {
420 // swap fec_col and fec_col_tmp
421 fec_tmp = s->fec_col[col_idx];
422 s->fec_col[col_idx] = s->fec_col_tmp[col_idx];
423 s->fec_col_tmp[col_idx] = fec_tmp;
424 }
425 memcpy(s->fec_col_tmp[col_idx]->bitstring, bitstring, s->bitstring_size);
426 s->fec_col_tmp[col_idx]->sn = AV_RB16(buf + 2);
427 s->fec_col_tmp[col_idx]->ts = AV_RB32(buf + 4);
428 } else {
429 xor_fast(s->fec_col_tmp[col_idx]->bitstring, bitstring,
430 s->fec_col_tmp[col_idx]->bitstring, s->bitstring_size);
431 }
432
433 // FEC (column) send block-aligned
434 if (!s->first && s->packet_idx % s->d == 0) {
435 col_out_idx = s->packet_idx / s->l;
436 if ((ret = prompeg_write_fec(h, s->fec_col[col_out_idx], PROMPEG_FEC_COL)) < 0)
437 goto end;
438 written += ret;
439 }
440
441 if (++s->packet_idx >= s->packet_idx_max) {
442 s->packet_idx = 0;
443 if (s->first)
444 s->first = 0;
445 }
446
447 ret = written;
448
449end:
450 av_free(bitstring);
451 return ret;
452}
453
454static int prompeg_close(URLContext *h) {
455 PrompegContext *s = h->priv_data;
456 int i;
457
458 ffurl_closep(&s->fec_col_hd);
459 ffurl_closep(&s->fec_row_hd);
460
461 if (s->fec_arr) {
462 for (i = 0; i < s->fec_arr_len; i++) {
463 av_free(s->fec_arr[i]->bitstring);
464 av_freep(&s->fec_arr[i]);
465 }
466 av_freep(&s->fec_arr);
467 }
468 av_freep(&s->rtp_buf);
469
470 return 0;
471}
472
473const URLProtocol ff_prompeg_protocol = {
474 .name = "prompeg",
475 .url_open = prompeg_open,
476 .url_write = prompeg_write,
477 .url_close = prompeg_close,
478 .priv_data_size = sizeof(PrompegContext),
479 .flags = URL_PROTOCOL_FLAG_NETWORK,
480 .priv_data_class = &prompeg_class,
481};
482
generated by cgit at 2024-05-17 06:08:24 (GMT)