fecdec_filter.c

   1 /*
   2  * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file fecdec_filter.c A filter that fec-decodes an audio stream. */
   8
   9 #include <regex.h>
  10 #include <stdbool.h>
  11
  12 #include <dirent.h>
  13 #include "para.h"
  14 #include "error.h"
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "ggo.h"
  18 #include "buffer_tree.h"
  19 #include "filter.h"
  20 #include "string.h"
  21 #include "portable_io.h"
  22 #include "fec.h"
  23 #include "fd.h"
  24
  25 /**
  26  * How many FEC groups to store in memory.
  27  *
  28  * Packet reordering requires to keep more than one FEC group in memory because
  29  * slices belonging to the next FEC group may arrive before the current FEC group
  30  * is complete.
  31  */
  32 #define NUM_FEC_GROUPS 3
  33
  34 /** Default size of the output buffer of the fecdec filter. */
  35 #define FECDEC_DEFAULT_OUTBUF_SIZE (3 * 1024)
  36 /** Maximal size of the output buffer of the fecdec filter. */
  37 #define FECDEC_MAX_OUTBUF_SIZE (1024 * 1024)
  38
  39 /** Data read from the header of a slice. */
  40 struct fec_header {
  41         /** Total number of slices in this group. */
  42         uint8_t slices_per_group;
  43         /** Number of slices needed to start decoding. */
  44         uint8_t data_slices_per_group;
  45         /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
  46         uint32_t audio_header_size;
  47         /** Number of the FEC group this slice belongs to. */
  48         uint32_t group_num;
  49         /** Size of the data in this FEC group. */
  50         uint32_t group_bytes;
  51         /** Number of this slice in the group. */
  52         uint8_t slice_num;
  53         /** Used data bytes of this slice. */
  54         uint16_t slice_bytes;
  55         /** Non-zero if this group is the beginning of the stream. */
  56         uint8_t bos;
  57         /** Non-zero if this stream embedds audio headers into fec groups. */
  58         uint8_t header_stream;
  59 };
  60
  61 /**
  62  * The status of one partially received FEC group.
  63  */
  64 struct fecdec_group {
  65         /** The header read from the last slice. */
  66         struct fec_header h;
  67         /** How many slices received so far. */
  68         int num_received_slices;
  69         /** The size of the \a idx and the \a data arrays below. */
  70         int num_slices;
  71         /** Array of indices of the received slices. */
  72         int *idx;
  73         /** Content of the received slices. */
  74         unsigned char **data;
  75 };
  76
  77 /**
  78  * Data private to the fecdec filter.
  79  */
  80 struct private_fecdec_data {
  81         /** Used by the fec core code. */
  82         struct fec_parms *fec;
  83         /** Keeps track of what was received so far. */
  84         struct fecdec_group groups[NUM_FEC_GROUPS];
  85         /** Whether an audio file header was already received. */
  86         int have_header;
  87         /** Points to the first received group. */
  88         struct fecdec_group *first_complete_group;
  89         struct btr_pool *btrp;
  90 };
  91
  92 /** Iterate over all fecdec groups. */
  93 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
  94         (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
  95
  96 static int group_complete(struct fecdec_group *fg)
  97 {
  98         return fg->num_received_slices >= fg->h.data_slices_per_group;
  99 }
 100
 101 static int group_empty(struct fecdec_group *fg)
 102 {
 103         return fg->num_received_slices == 0;
 104 }
 105
 106 static void clear_group(struct fecdec_group *fg)
 107 {
 108         int i;
 109
 110         for (i = 0; i < fg->num_slices; i++) {
 111                 free(fg->data[i]);
 112                 fg->data[i] = NULL;
 113                 fg->idx[i] = -1;
 114         }
 115         free(fg->data);
 116         fg->data = NULL;
 117         free(fg->idx);
 118         fg->idx = NULL;
 119         fg->num_slices = 0;
 120         memset(&fg->h, 0, sizeof(struct fec_header));
 121         fg->num_received_slices = 0;
 122 }
 123
 124 static int find_group(struct fec_header *h,
 125                 struct private_fecdec_data *pfd, struct fecdec_group **result)
 126 {
 127         struct fecdec_group *fg;
 128
 129         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 130                 if (fg->h.group_num != h->group_num)
 131                         continue;
 132                 if (fg->num_received_slices == 0)
 133                         goto success;
 134                 if (fg->h.slices_per_group != h->slices_per_group)
 135                         return -E_BAD_FEC_HEADER;
 136                 if (fg->h.data_slices_per_group != h->data_slices_per_group)
 137                         return -E_BAD_FEC_HEADER;
 138                 if (fg->h.group_bytes != h->group_bytes)
 139                         return -E_BAD_FEC_HEADER;
 140 success:
 141                 *result = fg;
 142                 return 1;
 143         }
 144         return 0;
 145 }
 146
 147 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
 148 {
 149         struct fecdec_group *fg;
 150
 151         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 152                 if (fg->num_received_slices == 0)
 153                         return fg;
 154         }
 155         return NULL;
 156 }
 157
 158 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
 159 {
 160         struct fecdec_group *fg;
 161
 162         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 163                 if (!group_complete(fg))
 164                         continue;
 165                 /*
 166                  * Don't clear the first complete group if it has not yet been
 167                  * decoded.
 168                  */
 169                 if (fg == pfd->first_complete_group)
 170                         continue;
 171                 clear_group(fg);
 172                 return fg;
 173         }
 174         return NULL;
 175 }
 176
 177 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
 178 {
 179         struct fecdec_group *fg, *oldest = NULL;
 180
 181         FOR_EACH_FECDEC_GROUP(fg, pfd) {
 182                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 183                         oldest = fg;
 184         }
 185         if (!group_complete(oldest) && !group_empty(oldest))
 186                 PARA_WARNING_LOG("Clearing incomplete group %d "
 187                         "(contains %d slices)\n", oldest->h.group_num,
 188                         oldest->num_received_slices);
 189         if (oldest == pfd->first_complete_group)
 190                 pfd->first_complete_group = NULL;
 191         clear_group(oldest);
 192         return oldest;
 193 }
 194
 195 /* returns 1 if the group was found, 0 if not, negative on errors */
 196 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 197                 struct fecdec_group **result)
 198 {
 199         struct fecdec_group *fg;
 200         int ret = find_group(h, pfd, &fg);
 201
 202         if (ret < 0)
 203                 return ret;
 204         if (ret > 0) /* found group */
 205                 goto success;
 206         /* group not found */
 207         fg = find_unused_group(pfd);
 208         if (fg)
 209                 goto success;
 210         fg = try_to_free_group(pfd);
 211         if (fg)
 212                 goto success;
 213         fg = free_oldest_group(pfd);
 214         ret = 0;
 215 success:
 216         fg->h = *h;
 217         *result = fg;
 218         return ret;
 219 }
 220
 221 /*
 222  * returns 1 if slice was added, zero otherwise (because the group was already
 223  * complete). In any case the number of received slices is being increased by
 224  * one.
 225  */
 226 static int add_slice(char *buf, struct fecdec_group *fg)
 227 {
 228         int r, slice_num;
 229
 230         if (group_complete(fg)) {
 231                 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
 232                         fg->h.group_num, fg->h.slice_num);
 233                 fg->num_received_slices++;
 234                 return 0;
 235         }
 236         slice_num = fg->h.slice_num;
 237         if (fg->num_slices == 0) {
 238                 fg->num_slices = fg->h.slices_per_group;
 239                 fg->idx = para_malloc(fg->num_slices * sizeof(int));
 240                 fg->data = para_malloc(fg->num_slices * sizeof(unsigned char *));
 241                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 242         }
 243         r = fg->num_received_slices;
 244         fg->idx[r] = slice_num;
 245         fg->data[r] = para_malloc(fg->h.slice_bytes);
 246         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 247         fg->num_received_slices++;
 248         return 1;
 249 }
 250
 251 /**
 252  * The different states of a complete FEC group.
 253  *
 254  * Even if a FEC group has been received successfully, it probably can not be
 255  * used right away because some streams (ogg, wma) need to receive an audio
 256  * file header before decoding can start.
 257  */
 258 enum fec_group_usability {
 259         /** Drop the group (because we did not receive the header yet). */
 260         FEC_GROUP_UNUSABLE,
 261         /** Use all data in the group. */
 262         FEC_GROUP_USABLE,
 263         /** Use the group, but drop its audio file header. */
 264         FEC_GROUP_USABLE_SKIP_HEADER,
 265         /** Use the group, including its header. */
 266         FEC_GROUP_USABLE_WITH_HEADER
 267 };
 268
 269 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
 270                 struct private_fecdec_data *pfd)
 271 {
 272         struct fec_header *h = &fg->h;
 273
 274         if (!h->header_stream)
 275                 return FEC_GROUP_USABLE;
 276         if (pfd->have_header) {
 277                 if (h->audio_header_size)
 278                         return FEC_GROUP_USABLE_SKIP_HEADER;
 279                 return FEC_GROUP_USABLE;
 280         }
 281         if (fg->h.bos)
 282                 return FEC_GROUP_USABLE;
 283         if (fg->h.audio_header_size)
 284                 return FEC_GROUP_USABLE_WITH_HEADER;
 285         return FEC_GROUP_UNUSABLE;
 286 }
 287
 288 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
 289 {
 290         int i, ret, sb = fg->h.slice_bytes;
 291         size_t written, need;
 292         struct private_fecdec_data *pfd = fn->private_data;
 293         enum fec_group_usability u = group_is_usable(fg, pfd);
 294         char *buf = NULL, *p;
 295
 296         if (u == FEC_GROUP_UNUSABLE) {
 297                 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
 298                 return 0;
 299         }
 300         PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
 301                 fg->h.data_slices_per_group);
 302         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 303         if (ret < 0)
 304                 return ret;
 305         pfd->have_header = 1;
 306         i = 0;
 307         if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
 308                 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
 309                         / fg->h.slice_bytes;
 310                 PARA_DEBUG_LOG("skipping %d header slices\n", i);
 311         }
 312         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 313                 fg->h.group_num, fg->h.group_bytes,
 314                 fg->h.data_slices_per_group * sb);
 315         if (fn->btrn) {
 316                 need = (fg->h.data_slices_per_group - i) * sb;
 317                 if (need > btr_pool_unused(pfd->btrp))
 318                         return -E_FECDEC_OVERRUN;
 319                 btr_pool_get_buffer(pfd->btrp, &buf);
 320                 p = buf;
 321         } else {
 322                 need = fn->loaded + (fg->h.data_slices_per_group - i) * sb;
 323                 if (need > fn->bufsize) {
 324                         fn->bufsize = PARA_MAX(fn->bufsize * 2, need);
 325                         if (fn->bufsize > FECDEC_MAX_OUTBUF_SIZE)
 326                                 return -E_FECDEC_OVERRUN;
 327                         PARA_INFO_LOG("increasing fec buf to %zu\n", fn->bufsize);
 328                         fn->buf = para_realloc(fn->buf, fn->bufsize);
 329                 }
 330                 p = fn->buf + fn->loaded;
 331         }
 332         if (u == FEC_GROUP_USABLE_WITH_HEADER) {
 333                 PARA_INFO_LOG("writing audio file header\n");
 334                 written = 0;
 335                 for (i = 0; i < fg->h.data_slices_per_group; i++) {
 336                         size_t n = sb;
 337                         if (written >= fg->h.audio_header_size)
 338                                 break;
 339                         if (sb + written > fg->h.audio_header_size)
 340                                 n = fg->h.audio_header_size - written;
 341                         if (fn->btrn)
 342                                 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 343                         else
 344                                 memcpy(p + written, fg->data[i], n);
 345                         fn->loaded += n;
 346                         written += n;
 347                 }
 348                 p += written;
 349         }
 350         written = 0;
 351         for (; i < fg->h.data_slices_per_group; i++) {
 352                 size_t n = sb;
 353                 if (n + written > fg->h.group_bytes)
 354                         n = fg->h.group_bytes - written;
 355                 if (fn->btrn)
 356                         btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
 357                 else
 358                         memcpy(p + written, fg->data[i], n);
 359                 fn->loaded += n;
 360                 written += n;
 361         }
 362         p += written;
 363         return 0;
 364 }
 365
 366 /**
 367  * Read a fec header from a buffer.
 368  *
 369  * \param buf The buffer to write to.
 370  * \param h The fec header to write.
 371  */
 372 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 373 {
 374         uint32_t magic;
 375
 376         if (len < FEC_HEADER_SIZE)
 377                 return 0;
 378         magic = read_u32(buf);
 379         if (magic != FEC_MAGIC)
 380                 return -E_BAD_FEC_HEADER;
 381         h->slices_per_group = read_u8(buf + 4);
 382         h->data_slices_per_group = read_u8(buf + 5);
 383         h->audio_header_size = read_u32(buf + 6);
 384
 385         h->group_num = read_u32(buf + 10);
 386         h->group_bytes = read_u32(buf + 14);
 387
 388         h->slice_num = read_u8(buf + 18);
 389         h->slice_bytes = read_u16(buf + 20);
 390         h->bos = read_u8(buf + 22);
 391         h->header_stream = read_u8(buf + 23);
 392         if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
 393                 return -E_FECDEC_EOF;
 394 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 395 //              h->group_num, h->slice_num, h->slices_per_group);
 396         return 1;
 397 }
 398
 399 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
 400 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 401                 struct filter_node *fn)
 402 {
 403         struct fecdec_group *fg;
 404         int ret, k, n;
 405         struct private_fecdec_data *pfd = fn->private_data;
 406
 407         if (h->slice_bytes > len) { /* can not use the thing, try to read more */
 408                 fn->min_iqs = h->slice_bytes + FEC_HEADER_SIZE;
 409                 return 0;
 410         }
 411         ret = get_group(h, pfd, &fg);
 412         if (ret < 0)
 413                 return ret;
 414         if (!add_slice(buf, fg)) /* group already complete */
 415                 return 1;
 416         if (!group_complete(fg))
 417                 return 1;
 418         /* this slice completed the group */
 419         if (pfd->fec)
 420                 goto decode;
 421         /* it's either the first or the second complete group */
 422         if (!pfd->first_complete_group) { /* it's the first group */
 423                 enum fec_group_usability u = group_is_usable(fg, pfd);
 424                 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
 425                 if (u == FEC_GROUP_UNUSABLE) /* forget it */
 426                         return 1;
 427                 pfd->first_complete_group = fg; /* remember it */
 428                 return 1;
 429         }
 430         /* we have two complete groups, let's go */
 431         k = h->data_slices_per_group;
 432         n = h->slices_per_group;
 433         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 434         ret = fec_new(k, n, &pfd->fec);
 435         if (ret < 0)
 436                 return ret;
 437         pfd->btrp = btr_pool_new("fecdec", 20 * k *  h->slice_bytes);
 438         /* decode and clear the first group */
 439         ret = decode_group(pfd->first_complete_group, fn);
 440         if (ret < 0)
 441                 return ret;
 442         clear_group(pfd->first_complete_group);
 443         pfd->first_complete_group = NULL;
 444 decode:
 445         ret = decode_group(fg, fn);
 446         if (ret < 0)
 447                 return ret;
 448         return 1;
 449 }
 450
 451 static void fecdec_close(struct filter_node *fn)
 452 {
 453         struct private_fecdec_data *pfd = fn->private_data;
 454         struct fecdec_group *fg;
 455
 456         FOR_EACH_FECDEC_GROUP(fg, pfd)
 457                 clear_group(fg);
 458         free(fn->buf);
 459         fn->buf = NULL;
 460         fec_free(pfd->fec);
 461         free(fn->private_data);
 462         fn->private_data = NULL;
 463         fn->conf = NULL;
 464 }
 465
 466 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
 467 {
 468         struct filter_node *fn = container_of(t, struct filter_node, task);
 469         struct btr_node *btrn = fn->btrn;
 470         int ret;
 471         struct fec_header h;
 472         char *buf;
 473         size_t len;
 474
 475 next_buffer:
 476         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 477         if (ret <= 0)
 478                 goto out;
 479         btr_merge(btrn, fn->min_iqs);
 480         len = btr_next_buffer(btrn, &buf);
 481         ret = read_fec_header(buf, len, &h);
 482         if (ret <= 0)
 483                 goto out;
 484         ret = -E_BAD_SLICE_SIZE;
 485         if (!h.slice_bytes)
 486                 goto out;
 487         ret = -E_BAD_SLICE_NUM;
 488         if (h.slice_num > h.slices_per_group)
 489                 goto out;
 490         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 491                 &h, fn);
 492         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 493         if (ret <= 0)
 494                 goto out;
 495         btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
 496         goto next_buffer;
 497 out:
 498         t->error = ret;
 499         if (ret < 0)
 500                 btr_remove_node(btrn);
 501 }
 502
 503 static void fecdec_open(struct filter_node *fn)
 504 {
 505         struct private_fecdec_data *pfd;
 506         fn->bufsize = FECDEC_DEFAULT_OUTBUF_SIZE;
 507         fn->buf = para_malloc(fn->bufsize);
 508         pfd = para_calloc(sizeof(*pfd));
 509         fn->private_data = pfd;
 510         fn->loaded = 0;
 511         fn->min_iqs = FEC_HEADER_SIZE;
 512 }
 513
 514 /**
 515  * The init function of the fecdec filter.
 516  *
 517  * \param f Struct to initialize.
 518  */
 519 void fecdec_filter_init(struct filter *f)
 520 {
 521         f->close = fecdec_close;
 522         f->open = fecdec_open;
 523         f->pre_select = generic_filter_pre_select;
 524         f->post_select = fecdec_post_select;
 525 }