libavformat/prompeg.c

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